Add proper handling for non-local references in nested functions
Commit Message
Kevin,
On 07/23/2015 02:39 AM, Kevin Buettner wrote:
> I had to make the following change in order to obtain a clean build
> using your patches:
>
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index e20aead..d6e3d55 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -11457,7 +11457,7 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
>
> newobj = pop_context ();
> /* Make a block for the local symbols within. */
> - block = finish_block (newobj->name, &newobj->static_link,
> + block = finish_block (newobj->name, newobj->static_link,
> &local_symbols, newobj->old_blocks,
> lowpc, highpc);
Huh, I actually have a warning I did not notice but not an error, so I
guess you built GDB as C++. Anyway, this is a big mistake that should
have broken the feature I intend to add: quite bad! Thank you very much
for pointing me at it.
I had a look at why testsuite was clean even with this error, and I
realized that all my testing was with the wrong compiler[1]: this part
of the code was actually not exercized... So I picked the proper
compiler and this time I saw this was not working! This time I fixed the
feature, built in C++ mode just to be sure. Here's the updated patch:
- I fixed yacc parsers in all languages so that block information
from symbol lookups are properly transmitted to returned expressions.
- I fixed the usage of hash table to save static link (I do mappings
in objfiles.c, not sets so my usage of htab was invalid).
So this time, tested both with a GCC release and a patched GCC: no
regression on x86_64-linux. I kept the "static link" terminology because
I'm waiting for a consensus before changing everything. ;-)
[1] In nested functions, an unpatched GCC creates local variables that
are references to the non-local ones, so the feature works at the user
level, but not using the static link machinery. The aim of my change is
to make GDB work even without these "fake" local reference variables.
Comments
On Thu, 23 Jul 2015 12:44:19 +0200
Pierre-Marie de Rodat <derodat@adacore.com> wrote:
> Kevin,
>
> On 07/23/2015 02:39 AM, Kevin Buettner wrote:
> > I had to make the following change in order to obtain a clean build
> > using your patches:
> >
> > diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> > index e20aead..d6e3d55 100644
> > --- a/gdb/dwarf2read.c
> > +++ b/gdb/dwarf2read.c
> > @@ -11457,7 +11457,7 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
> >
> > newobj = pop_context ();
> > /* Make a block for the local symbols within. */
> > - block = finish_block (newobj->name, &newobj->static_link,
> > + block = finish_block (newobj->name, newobj->static_link,
> > &local_symbols, newobj->old_blocks,
> > lowpc, highpc);
>
> Huh, I actually have a warning I did not notice but not an error, so I
> guess you built GDB as C++. Anyway, this is a big mistake that should
> have broken the feature I intend to add: quite bad! Thank you very much
> for pointing me at it.
I built it using GCC's C compiler, but with -Werror enabled. This flag
turns warnings into errors.
I'll test your new patch today. I've encountered a GDB bug related to
examining variables with within a nested function. I'm hoping that
your patch will fix it...
Kevin
On 07/23/2015 03:44 PM, Kevin Buettner wrote:
> I built it using GCC's C compiler, but with -Werror enabled. This flag
> turns warnings into errors.
I see... Thank you.
> I'll test your new patch today. I've encountered a GDB bug related to
> examining variables with within a nested function. I'm hoping that
> your patch will fix it...
I am as well: keep me updated! ;-)
On Thu, 23 Jul 2015 18:14:12 +0200
Pierre-Marie de Rodat <derodat@adacore.com> wrote:
> On 07/23/2015 03:44 PM, Kevin Buettner wrote:
>
> > I'll test your new patch today. I've encountered a GDB bug related to
> > examining variables with within a nested function. I'm hoping that
> > your patch will fix it...
>
> I am as well: keep me updated! ;-)
I ran into another issue, both yesterday and today, when attempting to
apply your patch. Apparently, it adds some test cases,
gdb.base/nested-subp1.c, gdb.base/nested-subp1.exp, etc. which already
exist. As can be seen in the log below, I told patch to not assume -R
as well as to not apply the patch. I'm using sources, current as of
yesterday, upon which I first applied your other patch,
0001-Replace-the-block_found-global-with-explicit-data-fl.patch.
Here's the log showing the issue I ran into:
[kev@pinnacle gdb]$ patch -p2 </tmp/0001-DWARF-handle-non-local-references-in-nested-function.patch
patching file ada-lang.c
patching file block.c
patching file block.h
patching file buildsym.c
patching file buildsym.h
patching file c-exp.y
patching file coffread.c
patching file compile/compile-c-symbols.c
patching file compile/compile-loc2c.c
patching file d-exp.y
patching file dbxread.c
patching file dwarf2loc.c
patching file dwarf2loc.h
patching file dwarf2read.c
patching file f-exp.y
patching file findvar.c
patching file gdbtypes.c
patching file go-exp.y
patching file infcmd.c
patching file infrun.c
patching file jv-exp.y
patching file language.h
patching file m2-exp.y
patching file objfiles.c
patching file objfiles.h
patching file p-exp.y
patching file printcmd.c
patching file python/py-finishbreakpoint.c
patching file python/py-frame.c
patching file python/py-framefilter.c
patching file python/py-symbol.c
patching file stack.c
patching file symtab.h
The next patch would create the file testsuite/gdb.base/nested-subp1.c,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
The next patch would create the file testsuite/gdb.base/nested-subp1.exp,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
The next patch would create the file testsuite/gdb.base/nested-subp2.c,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
The next patch would create the file testsuite/gdb.base/nested-subp2.exp,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
The next patch would create the file testsuite/gdb.base/nested-subp3.c,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
The next patch would create the file testsuite/gdb.base/nested-subp3.exp,
which already exists! Assume -R? [n] n
Apply anyway? [n] n
Skipping patch.
1 out of 1 hunk ignored
patching file valops.c
patching file value.h
patching file xcoffread.c
On 07/23/2015 07:21 PM, Kevin Buettner wrote:
> I ran into another issue, both yesterday and today, when attempting to
> apply your patch. Apparently, it adds some test cases,
> gdb.base/nested-subp1.c, gdb.base/nested-subp1.exp, etc. which already
> exist. As can be seen in the log below, I told patch to not assume -R
> as well as to not apply the patch. I'm using sources, current as of
> yesterday, upon which I first applied your other patch,
> 0001-Replace-the-block_found-global-with-explicit-data-fl.patch.
Huh, strange! I think you have a dirty source tree: I just fetched the
upstream repository and I have this:
$ git annotate fsf/master -- gdb/testsuite/gdb.base/nested-subp1.exp
fatal: no such path gdb/testsuite/gdb.base/nested-subp1.exp in
fsf/master
So I guess you should check the state of your source tree with "git status".
> Here's the log showing the issue I ran into:
>
> [kev@pinnacle gdb]$ patch -p2 </tmp/0001-DWARF-handle-non-local-references-in-nested-function.patch
> patching file ada-lang.c
> [...]
> The next patch would create the file testsuite/gdb.base/nested-subp1.c,
> which already exists! Assume -R? [n] n
> Apply anyway? [n] n
> [...]
I would suggest you to use "git am" to import patches: this will keep
track of which change comes from which commit. If you want a quick
discussion for this matter, I'm on IRC (#gdb), by the way.
On Thu, 23 Jul 2015 19:33:52 +0200
Pierre-Marie de Rodat <derodat@adacore.com> wrote:
> On 07/23/2015 07:21 PM, Kevin Buettner wrote:
> > I ran into another issue, both yesterday and today, when attempting to
> > apply your patch. Apparently, it adds some test cases,
> > gdb.base/nested-subp1.c, gdb.base/nested-subp1.exp, etc. which already
> > exist. As can be seen in the log below, I told patch to not assume -R
> > as well as to not apply the patch. I'm using sources, current as of
> > yesterday, upon which I first applied your other patch,
> > 0001-Replace-the-block_found-global-with-explicit-data-fl.patch.
>
> Huh, strange! I think you have a dirty source tree: I just fetched the
> upstream repository and I have this:
>
> $ git annotate fsf/master -- gdb/testsuite/gdb.base/nested-subp1.exp
> fatal: no such path gdb/testsuite/gdb.base/nested-subp1.exp in
> fsf/master
>
> So I guess you should check the state of your source tree with "git status".
I think you're right. Sorry for the false alarm!
> > Here's the log showing the issue I ran into:
> >
> > [kev@pinnacle gdb]$ patch -p2 </tmp/0001-DWARF-handle-non-local-references-in-nested-function.patch
> > patching file ada-lang.c
> > [...]
> > The next patch would create the file testsuite/gdb.base/nested-subp1.c,
> > which already exists! Assume -R? [n] n
> > Apply anyway? [n] n
> > [...]
>
> I would suggest you to use "git am" to import patches: this will keep
> track of which change comes from which commit. If you want a quick
> discussion for this matter, I'm on IRC (#gdb), by the way.
I'll look into this too. Thanks!
Kevin
On Thu, 23 Jul 2015 18:14:12 +0200
Pierre-Marie de Rodat <derodat@adacore.com> wrote:
> On 07/23/2015 03:44 PM, Kevin Buettner wrote:
>
> > I'll test your new patch today. I've encountered a GDB bug related to
> > examining variables with within a nested function. I'm hoping that
> > your patch will fix it...
>
> I am as well: keep me updated! ;-)
Your patch did indeed fix my problem.
Given this test case (which I cobbled together while looking at another
matter)...
--- nested.c ---
int
main ()
{
static int a = 1, b = 2, c = 3;
int d = 4, e = 5, f = 6;
void p (void)
{
c = 7;
f = 8;
__builtin_printf ("%d %d %d %d\n", b, c, e, f);
}
p ();
a = 101; b = 102; c = 103;
d = 104; e = 105; f = 106;
p ();
return 0;
}
--- end nested.c ---
...this is the behavior that I was seeing (without your patch):
Breakpoint 1, p () at nested.c:11
11 __builtin_printf ("%d %d %d %d\n", b, c, e, f);
(gdb) p a
$1 = 1
(gdb) p b
$2 = 2
(gdb) p c
$3 = 7
(gdb) p d
$4 = 32767
(gdb) p e
$5 = 5
(gdb) p f
$6 = 8
Note that the value of d is wrong.
Now, with your patch, this is what I see:
Breakpoint 1, p () at nested.c:11
11 __builtin_printf ("%d %d %d %d\n", b, c, e, f);
(gdb) p a
$1 = 1
(gdb) p b
$2 = 2
(gdb) p c
$3 = 7
(gdb) p d
$4 = 4
(gdb) p e
$5 = 5
(gdb) p f
$6 = 8
So, with your patch, the value of d is correct.
I don't know why, but with your patch from yesterday, I was still
seeing the faulty behavior. (It is possible that I messed up with
my testing...)
Kevin
Hi Pierre-Marie,
On Thu, 23 Jul 2015 11:06:53 -0700
Kevin Buettner <kevinb@redhat.com> wrote:
> --- nested.c ---
> int
> main ()
> {
> static int a = 1, b = 2, c = 3;
> int d = 4, e = 5, f = 6;
>
> void p (void)
> {
> c = 7;
> f = 8;
> __builtin_printf ("%d %d %d %d\n", b, c, e, f);
> }
>
> p ();
>
> a = 101; b = 102; c = 103;
> d = 104; e = 105; f = 106;
>
> p ();
>
> return 0;
> }
> --- end nested.c ---
I came across something else (for someone) to ponder while playing with
the above code. I don't necessarily expect your current patch to handle
this case, but since you've been looking at nested subprograms, you may
have some insight into what's happening.
The situation is that I want to place a breakpoint on the function p().
How do I do this?
This is what I've tried:
1) Placing a breakpoint on p without qualification does not work:
(gdb) b p
Function "p" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
2) Placing a breakpoint on main::p doesn't work:
(gdb) b main::p
Function "main::p" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
3a) However, the completion mechanism seems to think that p is a viable
candidate for a breakpoint:
(gdb) b p
p printf printf@plt
3b) But, as in (1), when we try it (by hitting <Enter> here), it
does not work:
Function "p" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
4) Perhaps p will be visible if we run to a breakpoint in main? (Nope.)
(gdb) b main
Breakpoint 1 at 0x400525: file nested.c, line 5.
(gdb) run
Starting program: /mesquite2/.ironwood2/1158876/nested
Breakpoint 1, main () at nested.c:5
5 int d = 4, e = 5, f = 6;
(gdb) b p
Function "p" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
(gdb)
So, there it is.
I want to be perfectly clear that I do NOT want this issue to hold up
your patch. I'm just throwing it out there in case you want to look
at it.
Kevin
On 07/23/2015 08:06 PM, Kevin Buettner wrote:
> Your patch did indeed fix my problem.
>
> Given this test case (which I cobbled together while looking at another
> matter)...
> [...]
> Breakpoint 1, p () at nested.c:11
> 11 __builtin_printf ("%d %d %d %d\n", b, c, e, f);
> (gdb) p a
> $1 = 1
> (gdb) p b
> $2 = 2
> (gdb) p c
> $3 = 7
> (gdb) p d
> $4 = 32767
> (gdb) p e
> $5 = 5
> (gdb) p f
> $6 = 8
>
> Note that the value of d is wrong.
Out of curiosity, I had a quick look and I understood what is going on
(without my most recent patch) in this example:
a, b and c are static variables, so they aren't on the stack and thus
GDB locates/prints them correctly. The e and f non-local variables are
referenced from p and thus GCC materializes them as local references in
the debug. info. for p, so GDB locates/prints the correctly.
d is both located on the outer frame and not referenced from p, so the
only description GDB has is the outer scope variable... which is
incorrectly used to locate/print the variable as of today.
> So, with your patch, the value of d is correct.
>
> I don't know why, but with your patch from yesterday, I was still
> seeing the faulty behavior. (It is possible that I messed up with
> my testing...)
That's most likely because my previous patch was broken, as I said in
the first mail I sent on Thursday. ;-)
On 07/23/2015 08:22 PM, Kevin Buettner wrote:
> I came across something else (for someone) to ponder while playing with
> the above code. I don't necessarily expect your current patch to handle
> this case, but since you've been looking at nested subprograms, you may
> have some insight into what's happening.
>
> The situation is that I want to place a breakpoint on the function p().
> How do I do this?
> 1) Placing a breakpoint on p without qualification does not work:
>
> (gdb) b p
> Function "p" not defined.
> Make breakpoint pending on future shared library load? (y or [n]) n
For the record, this works in Ada:
-- foo.adb
procedure Foo is
procedure Nested is
begin
null;
end Nested;
begin
Nested;
end Foo;
# Program isn't even started.
(gdb) b nested
Breakpoint 1 at 0x401cca: file foo.adb, line 4.
Bottom line is: the difference between the C and the Ada examples
resides in the partial symbols lookup: in the C example, only the outer
function has a partial symbol while in the Ada example, Nested has one
too. Why? Well, in dwarf2read.c:add_partial_subprogram there's a special
case for Ada that recurses over the child DIE. Stopping investigation
here. ;-)
> 4) Perhaps p will be visible if we run to a breakpoint in main? (Nope.)
>
> (gdb) b main
> Breakpoint 1 at 0x400525: file nested.c, line 5.
> (gdb) run
> Starting program: /mesquite2/.ironwood2/1158876/nested
I had a quick look at how breakpoints resolution works: it sems that
lookups don't take into account the block corresponding to the selected
frame. So trying to put the breakpoint during execution looks pointless.
> I want to be perfectly clear that I do NOT want this issue to hold up
> your patch. I'm just throwing it out there in case you want to look
> at it.
Sure. It was interesting to look at this, anyway.
Pierre-Marie de Rodat <derodat@adacore.com> writes:
> On 07/23/2015 08:22 PM, Kevin Buettner wrote:
>> I came across something else (for someone) to ponder while playing with
>> the above code. I don't necessarily expect your current patch to handle
>> this case, but since you've been looking at nested subprograms, you may
>> have some insight into what's happening.
>>
>> The situation is that I want to place a breakpoint on the function p().
>> How do I do this?
>
>> 1) Placing a breakpoint on p without qualification does not work:
>>
>> (gdb) b p
>> Function "p" not defined.
>> Make breakpoint pending on future shared library load? (y or [n]) n
>
> For the record, this works in Ada:
>
> -- foo.adb
> procedure Foo is
> procedure Nested is
> begin
> null;
> end Nested;
> begin
> Nested;
> end Foo;
>
> # Program isn't even started.
> (gdb) b nested
> Breakpoint 1 at 0x401cca: file foo.adb, line 4.
>
> Bottom line is: the difference between the C and the Ada examples
> resides in the partial symbols lookup: in the C example, only the
> outer function has a partial symbol while in the Ada example, Nested
> has one too. Why? Well, in dwarf2read.c:add_partial_subprogram there's
> a special case for Ada that recurses over the child DIE. Stopping
> investigation here. ;-)
Yeah, I can imagine that this is at least part of the reason.
We need to be as lazy as possible when reading partial syms
as it's a serious perf issue. OTOH sometimes we're too lazy
and then some things don't work.
Requiring hyperfast reading of partial syms is becoming
less important now that we have .gdb_index and soon something
in the DWARF standard. So I'm working on being more complete
in the partial sym reader.
>> 4) Perhaps p will be visible if we run to a breakpoint in main? (Nope.)
>>
>> (gdb) b main
>> Breakpoint 1 at 0x400525: file nested.c, line 5.
>> (gdb) run
>> Starting program: /mesquite2/.ironwood2/1158876/nested
>
> I had a quick look at how breakpoints resolution works: it sems that
> lookups don't take into account the block corresponding to the
> selected frame. So trying to put the breakpoint during execution looks
> pointless.
Yeah. We could probably do better here.
Pierre-Marie de Rodat <derodat@adacore.com> writes:
> Kevin,
>
> On 07/23/2015 02:39 AM, Kevin Buettner wrote:
>> I had to make the following change in order to obtain a clean build
>> using your patches:
>>
>> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
>> index e20aead..d6e3d55 100644
>> --- a/gdb/dwarf2read.c
>> +++ b/gdb/dwarf2read.c
>> @@ -11457,7 +11457,7 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
>>
>> newobj = pop_context ();
>> /* Make a block for the local symbols within. */
>> - block = finish_block (newobj->name, &newobj->static_link,
>> + block = finish_block (newobj->name, newobj->static_link,
>> &local_symbols, newobj->old_blocks,
>> lowpc, highpc);
>
> Huh, I actually have a warning I did not notice but not an error, so I
> guess you built GDB as C++. Anyway, this is a big mistake that should
> have broken the feature I intend to add: quite bad! Thank you very
> much for pointing me at it.
>
> I had a look at why testsuite was clean even with this error, and I
> realized that all my testing was with the wrong compiler[1]: this part
> of the code was actually not exercized... So I picked the proper
> compiler and this time I saw this was not working! This time I fixed
> the feature, built in C++ mode just to be sure. Here's the updated
> patch:
>
> - I fixed yacc parsers in all languages so that block information
> from symbol lookups are properly transmitted to returned expressions.
>
> - I fixed the usage of hash table to save static link (I do mappings
> in objfiles.c, not sets so my usage of htab was invalid).
>
> So this time, tested both with a GCC release and a patched GCC: no
> regression on x86_64-linux. I kept the "static link" terminology
> because I'm waiting for a consensus before changing everything. ;-)
>
>
> [1] In nested functions, an unpatched GCC creates local variables that
> are references to the non-local ones, so the feature works at the user
> level, but not using the static link machinery. The aim of my change
> is to make GDB work even without these "fake" local reference
> variables.
>
> --
> Pierre-Marie de Rodat
>
> From 2e65051fd50bb99985bbc2c8ed13c67514e9cc08 Mon Sep 17 00:00:00 2001
> From: Pierre-Marie de Rodat <derodat@adacore.com>
> Date: Thu, 5 Feb 2015 17:00:06 +0100
> Subject: [PATCH] DWARF: handle non-local references in nested functions
>
> GDB's current behavior when dealing with non-local references in the
> context of nested fuctions is approximative:
>
> - code using valops.c:value_of_variable read the first available stack
> frame that holds the corresponding variable (whereas there can be
> multiple candidates for this);
>
> - code directly relying on read_var_value will instead read non-local
> variables in frames where they are not even defined.
>
> This change adds the necessary context to symbol reads (to get the block
> they belong to) and to blocks (the static link property, if any) so that
> GDB can make the proper decisions when dealing with non-local varibale
> references.
>
> gdb/ChangeLog:
>
> * ada-lang.c (ada_read_var_value): Add a VAR_BLOCK argument and pass
> it to default_read_var_value.
> * block.c (block_static_link): New accessor.
> * block.h (block_static_link): Declare it.
> * buildsym.c (finish_block_internal): Add a static_link
> argument. If there is a static link, associate it to the new
> block.
> (finish_block): Add a static link argument and pass it to
> finish_block_internal.
> (end_symtab_get_static_block): Update calls to finish_block and
> to finish_block_internal.
> (end_symtab_with_blockvector): Update call to
> finish_block_internal.
> * buildsym.h: Forward-declare struct dynamic_prop.
> (struct context_stack): Add a static_link field.
> (finish_block): Add a static link argument.
> * c-exp.y: Remove an obsolete
> comment (evaluation of variables already start from the selected
> frame, and now they climb *up* the call stack) and propagate the
> block information to the produced expression.
> * d-exp.y: Likewise.
> * f-exp.y: Likewise.
> * go-exp.y: Likewise.
> * jv-exp.y: Likewise.
> * m2-exp.y: Likewise.
> * p-exp.y: Likewise.
> * coffread.c (coff_symtab_read): Update calls to finish_block.
> * dbxread.c (process_one_symbol): Likewise.
> * xcoffread.c (read_xcoff_symtab): Likewise.
> * compile/compile-c-symbols.c (convert_one_symbol): Add a
> VAR_BLOCK parameter and pass it to calls to read_var_value.
> (convert_symbol_sym): Pass the block corresponding to SYM to the
> call to convert_one_symbol.
> * compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Update
> call to read_var_value.
> * dwarf2loc.c (block_op_get_frame_base): New.
> (dwarf2_block_frame_base_locexpr_funcs): Implement the
> get_frame_base method.
> (dwarf2_block_frame_base_loclist_funcs): Likewise.
> (dwarf2locexpr_baton_eval): Add a frame argument and use it
> instead of the selected frame in order to evaluate the
> expression.
> (dwarf2_evaluate_property): Add a frame argument. Update call
> to dwarf2_locexpr_baton_eval to provide a frame in available and
> to handle the absence of address stack.
> * dwarf2loc.h (dwarf2_evaluate_property): Add a frame argument.
> * dwarf2read.c (attr_to_dynamic_prop): Add a forward
> declaration.
> (read_func_scope): Record any available static link description.
> Update call to finish_block.
> (read_lexical_block_scope): Update call to finish_block.
> * findvar.c (follow_static_link): New.
> (get_hosting_frame): New.
> (default_read_var_value): Add a VAR_BLOCK argument. Use
> get_hosting_frame to handle non-local references.
> (read_var_value): Add a VAR_BLOCK argument and pass it to the
> LA_READ_VAR_VALUE method.
> * gdbtypes.c (resolve_dynamic_range): Update calls to
> dwarf2_evaluate_property.
> (resolve_dynamic_type_internal): Likewise.
> * infcmd.c (finish_command_continuation): Update call to
> read_var_value, passing it the block coming from symbol lookup.
> * infrun.c (insert_exception_resume_breakpoint): Likewise.
> * language.h (struct language_defn): Add a VAR_BLOCK argument to
> the LA_READ_VAR_VALUE method.
> * objfiles.c (objfile_register_static_link): New.
> (objfile_lookup_static_link): New.
> (free_objfile): Free the STATIC_LINKS hashed map if needed.
> * objfiles.h: Include hashtab.h.
> (struct objfile): Add a STATIC_LINKS field.
> (objfile_register_static_link): New.
> (objfile_lookup_static_link): New.
> * printcmd.c (print_variable_and_value): Update call to
> read_var_value.
> * python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
> * python/py-frame.c (frapy_read_var): Update call to
> read_var_value, passing it the block coming from symbol lookup.
> * python/py-framefilter.c (extract_sym): Add a SYM_BLOCK
> parameter and set the pointed value to NULL (TODO).
> (enumerate_args): Update call to extract_sym.
> (enumerate_locals): Update calls to extract_sym and to
> read_var_value.
> * python/py-symbol.c (sympy_value): Update call to
> read_var_value (TODO).
> * stack.c (read_frame_local): Update call to read_var_value.
> (read_frame_arg): Likewise.
> (return_command): Likewise.
> * symtab.h (struct symbol_block_ops): Add a get_frame_base
> method.
> (struct symbol): Add a block field.
> (SYMBOL_BLOCK): New accessor.
> * valops.c (value_of_variable): Remove frame/block handling and
> pass the block argument to read_var_value, which does this job
> now.
> (value_struct_elt_for_reference): Update calls to
> read_var_value.
> (value_of_this): Pass the block found to read_var_value.
> * value.h (read_var_value): Add a VAR_BLOCK argument.
> (default_read_var_value): Likewise.
>
> gdb/testsuite/ChangeLog:
>
> * gdb.base/nested-subp1.exp: New file.
> * gdb.base/nested-subp1.c: New file.
> * gdb.base/nested-subp2.exp: New file.
> * gdb.base/nested-subp2.c: New file.
> * gdb.base/nested-subp3.exp: New file.
> * gdb.base/nested-subp3.c: New file.
>...
Hi.
Several nits and questions inline. grep for ====.
One thing I still want to do is take this patch and run it through
the perf testsuite.
Also, I still need to look at follow_static_link, get_hosting_frame closer.
Cool stuff though, there's clearly missing functionality we need here.
>
> diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
> index ded195f..5c43a7a 100644
> --- a/gdb/ada-lang.c
> +++ b/gdb/ada-lang.c
> @@ -13750,7 +13750,8 @@ ada_get_symbol_name_cmp (const char *lookup_name)
> /* Implement the "la_read_var_value" language_defn method for Ada. */
>
> static struct value *
> -ada_read_var_value (struct symbol *var, struct frame_info *frame)
> +ada_read_var_value (struct symbol *var, const struct block *var_block,
> + struct frame_info *frame)
> {
> const struct block *frame_block = NULL;
> struct symbol *renaming_sym = NULL;
> @@ -13766,7 +13767,7 @@ ada_read_var_value (struct symbol *var, struct frame_info *frame)
>
> /* This is a typical case where we expect the default_read_var_value
> function to work. */
> - return default_read_var_value (var, frame);
> + return default_read_var_value (var, var_block, frame);
> }
>
> const struct language_defn ada_language_defn = {
> diff --git a/gdb/block.c b/gdb/block.c
> index f7621aa..f4b8e4f 100644
> --- a/gdb/block.c
> +++ b/gdb/block.c
> @@ -428,6 +428,21 @@ set_block_compunit_symtab (struct block *block, struct compunit_symtab *cu)
> gb->compunit_symtab = cu;
> }
>
> +/* See block.h. */
> +
> +struct dynamic_prop *
> +block_static_link (const struct block *block)
> +{
> + struct objfile *objfile = block_objfile (block);
> +
> + /* Only objfile-owned blocks that materialize top function scopes can have
> + static links. */
> + if (objfile == NULL || BLOCK_FUNCTION (block) == NULL)
> + return NULL;
> +
> + return (struct dynamic_prop *) objfile_lookup_static_link (objfile, block);
> +}
> +
> /* Return the compunit of the global block. */
>
> static struct compunit_symtab *
> diff --git a/gdb/block.h b/gdb/block.h
> index d8ad343..6e7d247 100644
> --- a/gdb/block.h
> +++ b/gdb/block.h
> @@ -190,6 +190,12 @@ extern struct block *allocate_global_block (struct obstack *obstack);
> extern void set_block_compunit_symtab (struct block *,
> struct compunit_symtab *);
>
> +/* Return a property to evaluate the static link associated to BLOCK. Note
> + that only objfile-owned and function-level blocks can have a static link.
> + Return NULL if there is no such property. */
> +
====
Add a comment here stating that the term "static_link" is derived from
DW_AT_static_link.
> +extern struct dynamic_prop *block_static_link (const struct block *block);
> +
> /* A block iterator. This structure should be treated as though it
> were opaque; it is only defined here because we want to support
> stack allocation of iterators. */
> diff --git a/gdb/buildsym.c b/gdb/buildsym.c
> index 2a24a25..a2be2cb 100644
> --- a/gdb/buildsym.c
> +++ b/gdb/buildsym.c
> @@ -331,7 +331,8 @@ free_pending_blocks (void)
> file). Put the block on the list of pending blocks. */
>
> static struct block *
> -finish_block_internal (struct symbol *symbol, struct pending **listhead,
> +finish_block_internal (struct symbol *symbol, struct dynamic_prop *static_link,
> + struct pending **listhead,
> struct pending_block *old_blocks,
====
Move the static_link property here.
[Arguments to functions aren't in completely random order,
and here static_link is among the collection of random things
about the block like start,end. So it reads better to me if
static_link appears with start,end]
> CORE_ADDR start, CORE_ADDR end,
> int is_global, int expandable)
> @@ -422,6 +423,9 @@ finish_block_internal (struct symbol *symbol, struct pending **listhead,
> BLOCK_FUNCTION (block) = NULL;
> }
>
> + if (static_link != NULL)
> + objfile_register_static_link (objfile, block, static_link);
> +
> /* Now "free" the links of the list, and empty the list. */
>
> for (next = *listhead; next; next = next1)
> @@ -512,11 +516,12 @@ finish_block_internal (struct symbol *symbol, struct pending **listhead,
> }
>
> struct block *
> -finish_block (struct symbol *symbol, struct pending **listhead,
> +finish_block (struct symbol *symbol, struct dynamic_prop *static_link,
> + struct pending **listhead,
> struct pending_block *old_blocks,
> CORE_ADDR start, CORE_ADDR end)
> {
> - return finish_block_internal (symbol, listhead, old_blocks,
> + return finish_block_internal (symbol, static_link, listhead, old_blocks,
> start, end, 0, 0);
> }
>
> @@ -1218,7 +1223,7 @@ end_symtab_get_static_block (CORE_ADDR end_addr, int expandable, int required)
> struct context_stack *cstk = pop_context ();
>
> /* Make a block for the local symbols within. */
> - finish_block (cstk->name, &local_symbols, cstk->old_blocks,
> + finish_block (cstk->name, NULL, &local_symbols, cstk->old_blocks,
> cstk->start_addr, end_addr);
>
> if (context_stack_depth > 0)
> @@ -1289,7 +1294,7 @@ end_symtab_get_static_block (CORE_ADDR end_addr, int expandable, int required)
> else
> {
> /* Define the STATIC_BLOCK. */
> - return finish_block_internal (NULL, &file_symbols, NULL,
> + return finish_block_internal (NULL, NULL, &file_symbols, NULL,
> last_source_start_addr, end_addr,
> 0, expandable);
> }
> @@ -1317,7 +1322,7 @@ end_symtab_with_blockvector (struct block *static_block,
> end_addr = BLOCK_END (static_block);
>
> /* Create the GLOBAL_BLOCK and build the blockvector. */
> - finish_block_internal (NULL, &global_symbols, NULL,
> + finish_block_internal (NULL, NULL, &global_symbols, NULL,
> last_source_start_addr, end_addr,
> 1, expandable);
> blockvector = make_blockvector ();
> diff --git a/gdb/buildsym.h b/gdb/buildsym.h
> index f98203e..8828ad2 100644
> --- a/gdb/buildsym.h
> +++ b/gdb/buildsym.h
> @@ -39,6 +39,8 @@ struct compunit_symtab;
> struct block;
> struct pending_block;
>
> +struct dynamic_prop;
> +
> #ifndef EXTERN
> #define EXTERN extern
> #endif
> @@ -141,6 +143,11 @@ struct context_stack
>
> struct symbol *name;
>
> + /* Expression that computes the frame base of the lexically enclosing
> + function, if any. NULL otherwise. */
> +
> + struct dynamic_prop *static_link;
> +
> /* PC where this context starts */
>
> CORE_ADDR start_addr;
> @@ -192,9 +199,10 @@ extern struct symbol *find_symbol_in_list (struct pending *list,
> char *name, int length);
>
> extern struct block *finish_block (struct symbol *symbol,
> - struct pending **listhead,
> - struct pending_block *old_blocks,
> - CORE_ADDR start, CORE_ADDR end);
> + struct dynamic_prop *static_link,
> + struct pending **listhead, struct
> + pending_block *old_blocks, CORE_ADDR start,
> + CORE_ADDR end);
>
> extern void record_block_range (struct block *,
> CORE_ADDR start, CORE_ADDR end_inclusive);
> diff --git a/gdb/c-exp.y b/gdb/c-exp.y
> index b408215..3b7e572 100644
> --- a/gdb/c-exp.y
> +++ b/gdb/c-exp.y
> @@ -1070,10 +1070,7 @@ variable: name_not_typename
> }
>
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> - /* We want to use the selected frame, not
> - another more inner frame which happens to
> - be in the same block. */
> - write_exp_elt_block (pstate, NULL);
> + write_exp_elt_block (pstate, sym.block);
> write_exp_elt_sym (pstate, sym.symbol);
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> }
> diff --git a/gdb/coffread.c b/gdb/coffread.c
> index 7722cdb..e41e9a5 100644
> --- a/gdb/coffread.c
> +++ b/gdb/coffread.c
> @@ -1144,7 +1144,7 @@ coff_symtab_read (long symtab_offset, unsigned int nsyms,
> enter_linenos (fcn_line_ptr, fcn_first_line,
> fcn_last_line, objfile);
>
> - finish_block (newobj->name, &local_symbols,
> + finish_block (newobj->name, NULL, &local_symbols,
> newobj->old_blocks, newobj->start_addr,
> fcn_cs_saved.c_value
> + fcn_aux_saved.x_sym.x_misc.x_fsize
> @@ -1188,7 +1188,7 @@ coff_symtab_read (long symtab_offset, unsigned int nsyms,
> cs->c_value + ANOFFSET (objfile->section_offsets,
> SECT_OFF_TEXT (objfile));
> /* Make a block for the local symbols within. */
> - finish_block (0, &local_symbols, newobj->old_blocks,
> + finish_block (0, NULL, &local_symbols, newobj->old_blocks,
> newobj->start_addr, tmpaddr);
> }
> /* Now pop locals of block just finished. */
> diff --git a/gdb/compile/compile-c-symbols.c b/gdb/compile/compile-c-symbols.c
> index 5f27583..f1dfccf 100644
> --- a/gdb/compile/compile-c-symbols.c
> +++ b/gdb/compile/compile-c-symbols.c
> @@ -134,16 +134,16 @@ symbol_substitution_name (struct symbol *sym)
> return concat ("__", SYMBOL_NATURAL_NAME (sym), "_ptr", (char *) NULL);
> }
>
> -/* Convert a given symbol, SYM, to the compiler's representation.
> - CONTEXT is the compiler instance. IS_GLOBAL is true if the
> - symbol came from the global scope. IS_LOCAL is true if the symbol
> - came from a local scope. (Note that the two are not strictly
> - inverses because the symbol might have come from the static
> - scope.) */
> +/* Convert a given symbol, SYM (located in VAR_BLOCK, if any), to the
> + compiler's representation. CONTEXT is the compiler instance. IS_GLOBAL is
> + true if the symbol came from the global scope. IS_LOCAL is true if the
> + symbol came from a local scope. (Note that the two are not strictly
> + inverses because the symbol might have come from the static scope.) */
>
> static void
> convert_one_symbol (struct compile_c_instance *context,
> struct symbol *sym,
> + const struct block *var_block,
> int is_global,
> int is_local)
> {
> @@ -247,7 +247,7 @@ convert_one_symbol (struct compile_c_instance *context,
> SYMBOL_PRINT_NAME (sym));
> }
>
> - val = read_var_value (sym, frame);
> + val = read_var_value (sym, var_block, frame);
> if (VALUE_LVAL (val) != lval_memory)
> error (_("Symbol \"%s\" cannot be used for compilation "
> "evaluation as its address has not been found."),
> @@ -339,7 +339,8 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
> fprintf_unfiltered (gdb_stdlog,
> "gcc_convert_symbol \"%s\": global symbol\n",
> identifier);
> - convert_one_symbol (context, global_sym.symbol, 1, 0);
> + convert_one_symbol (context, global_sym.symbol, global_sym.block, 1,
> + 0);
> }
> }
>
> @@ -347,7 +348,7 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
> fprintf_unfiltered (gdb_stdlog,
> "gcc_convert_symbol \"%s\": local symbol\n",
> identifier);
> - convert_one_symbol (context, sym, 0, is_local_symbol);
> + convert_one_symbol (context, sym, block, 0, is_local_symbol);
> }
>
> /* Convert a minimal symbol to its gcc form. CONTEXT is the compiler
> diff --git a/gdb/compile/compile-loc2c.c b/gdb/compile/compile-loc2c.c
> index 6f53814..18ca4ae 100644
> --- a/gdb/compile/compile-loc2c.c
> +++ b/gdb/compile/compile-loc2c.c
> @@ -636,7 +636,7 @@ do_compile_dwarf_expr_to_c (int indent, struct ui_file *stream,
> "there is no selected frame"),
> SYMBOL_PRINT_NAME (sym));
>
> - val = read_var_value (sym, frame);
> + val = read_var_value (sym, NULL, frame);
> if (VALUE_LVAL (val) != lval_memory)
> error (_("Symbol \"%s\" cannot be used for compilation evaluation "
> "as its address has not been found."),
> diff --git a/gdb/d-exp.y b/gdb/d-exp.y
> index c95222b..336b671 100644
> --- a/gdb/d-exp.y
> +++ b/gdb/d-exp.y
> @@ -1066,9 +1066,7 @@ push_variable (struct parser_state *ps, struct stoken name)
> }
>
> write_exp_elt_opcode (ps, OP_VAR_VALUE);
> - /* We want to use the selected frame, not another more inner frame
> - which happens to be in the same block. */
> - write_exp_elt_block (ps, NULL);
> + write_exp_elt_block (ps, sym.block);
> write_exp_elt_sym (ps, sym.symbol);
> write_exp_elt_opcode (ps, OP_VAR_VALUE);
> return 1;
> diff --git a/gdb/dbxread.c b/gdb/dbxread.c
> index 6098b35..32893f6 100644
> --- a/gdb/dbxread.c
> +++ b/gdb/dbxread.c
> @@ -2766,8 +2766,8 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
> newobj = pop_context ();
>
> /* Make a block for the local symbols within. */
> - block = finish_block (newobj->name, &local_symbols,
> - newobj->old_blocks,
> + block = finish_block (newobj->name, NULL,
> + &local_symbols, newobj->old_blocks,
> newobj->start_addr, newobj->start_addr + valu);
>
> /* For C++, set the block's scope. */
> @@ -2868,7 +2868,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
> newobj->start_addr = valu;
> }
> /* Make a block for the local symbols within. */
> - finish_block (0, &local_symbols, newobj->old_blocks,
> + finish_block (0, NULL, &local_symbols, newobj->old_blocks,
> newobj->start_addr, valu);
> }
> }
> @@ -3165,7 +3165,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
>
> newobj = pop_context ();
> /* Make a block for the local symbols within. */
> - block = finish_block (newobj->name, &local_symbols,
> + block = finish_block (newobj->name, NULL, &local_symbols,
> newobj->old_blocks, newobj->start_addr,
> valu);
>
> diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
> index c75767e..edfa220 100644
> --- a/gdb/dwarf2loc.c
> +++ b/gdb/dwarf2loc.c
> @@ -381,12 +381,42 @@ locexpr_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
> *start = symbaton->data;
> }
>
> +/* Implement the struct symbol_block_ops::get_frame_base method. */
> +
> +static CORE_ADDR
> +block_op_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
> +{
> + if (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL)
> + {
> + struct gdbarch *gdbarch = get_frame_arch (frame);
> + struct type *type = builtin_type (gdbarch)->builtin_data_ptr;
> + struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (framefunc);
> + const gdb_byte *start;
> + size_t length;
> + struct value *result;
> +
> + SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
> + (framefunc, get_frame_pc (frame), &start, &length);
> + result = dwarf2_evaluate_loc_desc (type, frame, start, length,
> + dlbaton->per_cu);
> +
> + /* The DW_AT_frame_base attribute contains a location description which
> + computes the base address itself. However, the call to
> + dwarf2_evaluate_loc_desc returns a value representing a variable at
> + that address. The frame base address is thus this variable's
> + address. */
> + return value_address (result);
> + }
> + return 0;
> +}
====
If this is implemented on top of symbol_block_ops::find_frame_base_location,
do we need another method? Or can we just have a wrapper that calls
find_frame_base_location?
For one, I see block_op_get_frame_base being used for both
dwarf2_block_frame_base_locexpr_funcs and
dwarf2_block_frame_base_loclist_funcs.
> +
> /* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
> function uses DWARF expression for its DW_AT_frame_base. */
>
> const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs =
> {
> - locexpr_find_frame_base_location
> + locexpr_find_frame_base_location,
> + block_op_get_frame_base
> };
>
> /* Implement find_frame_base_location method for LOC_BLOCK functions using
> @@ -406,7 +436,8 @@ loclist_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
>
> const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs =
> {
> - loclist_find_frame_base_location
> + loclist_find_frame_base_location,
> + block_op_get_frame_base
> };
>
> /* See dwarf2loc.h. */
> @@ -2396,13 +2427,14 @@ dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
> }
>
> /* Evaluates a dwarf expression and stores the result in VAL, expecting
> - that the dwarf expression only produces a single CORE_ADDR. ADDR is a
> - context (location of a variable) and might be needed to evaluate the
> - location expression.
> + that the dwarf expression only produces a single CORE_ADDR. FRAME is the
> + frame in which the expression is evaluated. ADDR is a context (location of
> + a variable) and might be needed to evaluate the location expression.
> Returns 1 on success, 0 otherwise. */
>
> static int
> dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
> + struct frame_info *frame,
> CORE_ADDR addr,
> CORE_ADDR *valp)
> {
> @@ -2417,7 +2449,7 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
> ctx = new_dwarf_expr_context ();
> cleanup = make_cleanup_free_dwarf_expr_context (ctx);
>
> - baton.frame = get_selected_frame (NULL);
> + baton.frame = frame;
> baton.per_cu = dlbaton->per_cu;
> baton.obj_address = addr;
>
> @@ -2461,19 +2493,24 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
>
> int
> dwarf2_evaluate_property (const struct dynamic_prop *prop,
> + struct frame_info *frame,
> struct property_addr_info *addr_stack,
> CORE_ADDR *value)
> {
> if (prop == NULL)
> return 0;
>
> + if (frame == NULL && has_stack_frames ())
> + frame = get_selected_frame (NULL);
> +
> switch (prop->kind)
> {
> case PROP_LOCEXPR:
> {
> const struct dwarf2_property_baton *baton = prop->data.baton;
>
> - if (dwarf2_locexpr_baton_eval (&baton->locexpr, addr_stack->addr,
> + if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
> + addr_stack ? addr_stack->addr : 0,
> value))
> {
> if (baton->referenced_type)
> @@ -2490,7 +2527,6 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
> case PROP_LOCLIST:
> {
> struct dwarf2_property_baton *baton = prop->data.baton;
> - struct frame_info *frame = get_selected_frame (NULL);
> CORE_ADDR pc = get_frame_address_in_block (frame);
> const gdb_byte *data;
> struct value *val;
> diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
> index f3630ac..2415656 100644
> --- a/gdb/dwarf2loc.h
> +++ b/gdb/dwarf2loc.h
> @@ -122,12 +122,19 @@ struct property_addr_info
> struct property_addr_info *next;
> };
>
> -/* Converts a dynamic property into a static one. ADDR_STACK is the stack
> - of addresses that might be needed to evaluate the property.
> +/* Converts a dynamic property into a static one. FRAME is the frame in which
> + the property is evaluated; if NULL, the selected frame (if any) is used
> + instead.
> +
> + ADDR_STACK is the stack of addresses that might be needed to evaluate the
> + property. When evaluating a property that is not related to a type, it can
> + be NULL.
> +
> Returns 1 if PROP could be converted and the static value is passed back
> into VALUE, otherwise returns 0. */
>
> int dwarf2_evaluate_property (const struct dynamic_prop *prop,
> + struct frame_info *frame,
> struct property_addr_info *addr_stack,
> CORE_ADDR *value);
>
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index f440956..d6e3d55 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -1736,6 +1736,10 @@ static void load_full_type_unit (struct dwarf2_per_cu_data *per_cu);
>
> static void read_signatured_type (struct signatured_type *);
>
> +static int attr_to_dynamic_prop (const struct attribute *attr,
> + struct die_info *die, struct dwarf2_cu *cu,
> + struct dynamic_prop *prop);
> +
> /* memory allocation interface */
>
> static struct dwarf_block *dwarf_alloc_block (struct dwarf2_cu *);
> @@ -11393,6 +11397,16 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
> if (attr)
> dwarf2_symbol_mark_computed (attr, newobj->name, cu, 1);
>
> + /* If there is a location for the static link, record it. */
> + newobj->static_link = NULL;
> + attr = dwarf2_attr (die, DW_AT_static_link, cu);
> + if (attr)
> + {
> + newobj->static_link = obstack_alloc (&objfile->objfile_obstack,
> + sizeof (*newobj->static_link));
> + attr_to_dynamic_prop (attr, die, cu, newobj->static_link);
> + }
> +
> cu->list_in_scope = &local_symbols;
>
> if (die->child != NULL)
> @@ -11443,7 +11457,8 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
>
> newobj = pop_context ();
> /* Make a block for the local symbols within. */
> - block = finish_block (newobj->name, &local_symbols, newobj->old_blocks,
> + block = finish_block (newobj->name, newobj->static_link,
> + &local_symbols, newobj->old_blocks,
> lowpc, highpc);
>
> /* For C++, set the block's scope. */
> @@ -11529,7 +11544,7 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
> if (local_symbols != NULL || using_directives != NULL)
> {
> struct block *block
> - = finish_block (0, &local_symbols, newobj->old_blocks,
> + = finish_block (0, NULL, &local_symbols, newobj->old_blocks,
> newobj->start_addr, highpc);
>
> /* Note that recording ranges after traversing children, as we
> diff --git a/gdb/f-exp.y b/gdb/f-exp.y
> index c57f919..07892e0 100644
> --- a/gdb/f-exp.y
> +++ b/gdb/f-exp.y
> @@ -521,10 +521,7 @@ variable: name_not_typename
> innermost_block = sym.block;
> }
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> - /* We want to use the selected frame, not
> - another more inner frame which happens to
> - be in the same block. */
> - write_exp_elt_block (pstate, NULL);
> + write_exp_elt_block (pstate, sym.block);
> write_exp_elt_sym (pstate, sym.symbol);
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> break;
> diff --git a/gdb/findvar.c b/gdb/findvar.c
> index 2079b4b..38b9515 100644
> --- a/gdb/findvar.c
> +++ b/gdb/findvar.c
> @@ -32,6 +32,7 @@
> #include "block.h"
> #include "objfiles.h"
> #include "language.h"
> +#include "dwarf2loc.h"
>
> /* Basic byte-swapping routines. All 'extract' functions return a
> host-format integer from a target-format integer at ADDR which is
> @@ -409,11 +410,166 @@ minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data)
> return (data->result.minsym != NULL);
> }
>
> +/* Given static link expression and the frame it lives in, look for the frame
> + the static links points to and return it. Return NULL if we could not find
> + such a frame. */
> +
> +static struct frame_info *
> +follow_static_link (struct frame_info *frame,
> + const struct dynamic_prop *static_link)
> +{
> + CORE_ADDR upper_frame_base;
> +
> + if (!dwarf2_evaluate_property (static_link, frame, NULL, &upper_frame_base))
====
It gets harder and harder to reason about correctness the more
we blur lines between foo-independent and foo-dependent parts of gdb.
[In debug case "foo" == "debug-format".]
I guess to begin with, why are we calling a dwarf-specific function here
and what guarantees are in place (and easily discernable from reading
the code!) that the right thing will happen for non-dwarf targets?
> + return NULL;
> +
> + /* Now climb up the stack frame until we reach the frame we are interested
> + in. */
> + for (; frame != NULL; frame = get_prev_frame (frame))
> + {
> + struct symbol *framefunc = get_frame_function (frame);
> +
> + /* Protect ourselves against bad things such as circular call stacks. */
====
Here's a good question.
gdb has other mechanisms to catch corrupt (e.g., circular) stacks
(e.g., UNWIND_INNER_ID). Is this QUIT here for protection or in case
of really large stacks (e.g., due to infinite recursion)?
> + QUIT;
> +
> + /* If we don't know how to compute FRAME's base address, don't give up:
> + maybe the frame we are looking for is upper in the stace frame. */
> + if (framefunc != NULL
> + && SYMBOL_BLOCK_OPS (framefunc)->get_frame_base
====
!= NULL
> + && (SYMBOL_BLOCK_OPS (framefunc)->get_frame_base (framefunc, frame)
> + == upper_frame_base))
> + break;
> + }
> +
> + return frame;
> +}
> +
> +/* Assuming VAR is a symbol that can be reached from FRAME thanks to lexical
> + rules, look for the frame that is actually hosting VAR and return it. If,
> + for some reason, we found no such frame, return NULL.
> +
> + This kind of computation is necessary to correctly handle lexically nested
> + functions.
> +
> + Note that in some cases, we know what scope VAR comes from but we cannot
> + reach the specific frame that hosts the instance of VAR we are looking for.
> + For backward compatibility purposes (with old compilers), we then look for
> + the first frame that can host it. */
> +
> +static struct frame_info *
> +get_hosting_frame (struct symbol *var, const struct block *var_block,
> + struct frame_info *frame)
> +{
> + const struct block *frame_block = NULL;
> +
> + if (!symbol_read_needs_frame (var))
> + return NULL;
> +
> + /* Some symbols for local variables have no block: this happens when they are
> + not produced by a debug information reader, for instance when GDB creates
> + synthetic symbols. Without block information, we must assume they are
> + local to FRAME. In this case, there is nothing to do. */
> + else if (var_block == NULL)
> + return frame;
> +
> + /* We currently assume that all symbols with a location list need a frame.
> + This is true in practice because selecting the location description
> + requires to compute the CFA, hence requires a frame. However we have
> + tests that embed global/static symbols with null location lists.
> + We want to get <optimized out> instead of <frame required> when evaluating
> + them so return a frame instead of raising an error. */
> + else if (var_block == block_global_block (var_block)
> + || var_block == block_static_block (var_block))
> + return frame;
> +
> + /* We have to handle the "my_func::my_local_var" notation. This requires us
> + to look for upper frames when we find no block for the current frame: here
> + and below, handle when frame_block == NULL. */
> + if (frame != NULL)
> + frame_block = get_frame_block (frame, NULL);
> +
> + /* Climb up the call stack until reaching the frame we are looking for. */
> + while (frame != NULL && frame_block != var_block)
> + {
> + /* Protect ourselves against bad things such as circular call stacks. */
> + QUIT;
> +
> + if (frame_block == NULL)
> + {
> + frame = get_prev_frame (frame);
> + if (frame == NULL)
> + break;
> + frame_block = get_frame_block (frame, NULL);
> + }
> +
> + /* If we failed to find the proper frame, fallback to the heuristic
> + method below. */
> + else if (frame_block == block_global_block (frame_block))
> + {
> + frame = NULL;
> + break;
> + }
> +
> + /* Assuming we have a block for this frame: if we are at the function
> + level, the immediate upper lexical block is in an outer function:
> + follow the static link. */
> + else if (BLOCK_FUNCTION (frame_block))
> + {
> + const struct dynamic_prop *static_link
> + = block_static_link (frame_block);
> + int could_climb_up = 0;
> +
> + if (static_link != NULL)
> + {
> + frame = follow_static_link (frame, static_link);
> + if (frame != NULL)
> + {
> + frame_block = get_frame_block (frame, NULL);
> + could_climb_up = frame_block != NULL;
> + }
> + }
> + if (!could_climb_up)
> + {
> + frame = NULL;
> + break;
> + }
> + }
> +
> + else
> + /* We must be in some function nested lexical block. Just get the
> + outer block: both must share the same frame. */
> + frame_block = BLOCK_SUPERBLOCK (frame_block);
> + }
> +
> + /* Old compilers may not provide a static link, or they may provide an
> + invalid one. For such cases, fallback on the old way to evaluate
> + non-local references: just climb up the call stack and pick the first
> + frame that contains the variable we are looking for. */
> + if (frame == NULL)
> + {
> + frame = block_innermost_frame (var_block);
> + if (!frame)
> + {
> + if (BLOCK_FUNCTION (var_block)
> + && !block_inlined_p (var_block)
> + && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)))
> + error (_("No frame is currently executing in block %s."),
> + SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)));
> + else
> + error (_("No frame is currently executing in specified"
> + " block"));
> + }
> + }
> +
> + return frame;
> +}
> +
> /* A default implementation for the "la_read_var_value" hook in
> the language vector which should work in most situations. */
>
> struct value *
> -default_read_var_value (struct symbol *var, struct frame_info *frame)
> +default_read_var_value (struct symbol *var, const struct block *var_block,
> + struct frame_info *frame)
> {
> struct value *v;
> struct type *type = SYMBOL_TYPE (var);
> @@ -427,7 +583,10 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
> check_typedef (type);
>
> if (symbol_read_needs_frame (var))
> - gdb_assert (frame);
> + gdb_assert (frame != NULL);
> +
> + if (frame != NULL)
> + frame = get_hosting_frame (var, var_block, frame);
>
> if (SYMBOL_COMPUTED_OPS (var) != NULL)
> return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame);
> @@ -610,14 +769,15 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
> /* Calls VAR's language la_read_var_value hook with the given arguments. */
>
> struct value *
> -read_var_value (struct symbol *var, struct frame_info *frame)
> +read_var_value (struct symbol *var, const struct block *var_block,
> + struct frame_info *frame)
> {
> const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var));
>
> gdb_assert (lang != NULL);
> gdb_assert (lang->la_read_var_value != NULL);
>
> - return lang->la_read_var_value (var, frame);
> + return lang->la_read_var_value (var, var_block, frame);
> }
>
> /* Install default attributes for register values. */
> diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
> index be761e6..fe6af7c 100644
> --- a/gdb/gdbtypes.c
> +++ b/gdb/gdbtypes.c
> @@ -1874,7 +1874,7 @@ resolve_dynamic_range (struct type *dyn_range_type,
> gdb_assert (TYPE_CODE (dyn_range_type) == TYPE_CODE_RANGE);
>
> prop = &TYPE_RANGE_DATA (dyn_range_type)->low;
> - if (dwarf2_evaluate_property (prop, addr_stack, &value))
> + if (dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
> {
> low_bound.kind = PROP_CONST;
> low_bound.data.const_val = value;
> @@ -1886,7 +1886,7 @@ resolve_dynamic_range (struct type *dyn_range_type,
> }
>
> prop = &TYPE_RANGE_DATA (dyn_range_type)->high;
> - if (dwarf2_evaluate_property (prop, addr_stack, &value))
> + if (dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
> {
> high_bound.kind = PROP_CONST;
> high_bound.data.const_val = value;
> @@ -2128,7 +2128,8 @@ resolve_dynamic_type_internal (struct type *type,
>
> /* Resolve data_location attribute. */
> prop = TYPE_DATA_LOCATION (resolved_type);
> - if (prop != NULL && dwarf2_evaluate_property (prop, addr_stack, &value))
> + if (prop != NULL
> + && dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
> {
> TYPE_DYN_PROP_ADDR (prop) = value;
> TYPE_DYN_PROP_KIND (prop) = PROP_CONST;
> diff --git a/gdb/go-exp.y b/gdb/go-exp.y
> index 1f43306..9fa1bbd 100644
> --- a/gdb/go-exp.y
> +++ b/gdb/go-exp.y
> @@ -611,10 +611,7 @@ variable: name_not_typename
> }
>
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> - /* We want to use the selected frame, not
> - another more inner frame which happens to
> - be in the same block. */
> - write_exp_elt_block (pstate, NULL);
> + write_exp_elt_block (pstate, sym.block);
> write_exp_elt_sym (pstate, sym.symbol);
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> }
> diff --git a/gdb/infcmd.c b/gdb/infcmd.c
> index 4948d27..2872292 100644
> --- a/gdb/infcmd.c
> +++ b/gdb/infcmd.c
> @@ -1660,7 +1660,7 @@ finish_command_continuation (void *arg, int err)
> {
> struct value *func;
>
> - func = read_var_value (a->function, get_current_frame ());
> + func = read_var_value (a->function, NULL, get_current_frame ());
> TRY
> {
> /* print_return_value can throw an exception in some
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 9a46242..0844823 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -6082,14 +6082,13 @@ insert_exception_resume_breakpoint (struct thread_info *tp,
> {
> TRY
> {
> - struct symbol *vsym;
> + struct symbol_in_block vsym;
> struct value *value;
> CORE_ADDR handler;
> struct breakpoint *bp;
>
> - vsym = lookup_symbol (SYMBOL_LINKAGE_NAME (sym), b, VAR_DOMAIN,
> - NULL).symbol;
> - value = read_var_value (vsym, frame);
> + vsym = lookup_symbol (SYMBOL_LINKAGE_NAME (sym), b, VAR_DOMAIN, NULL);
> + value = read_var_value (vsym.symbol, vsym.block, frame);
> /* If the value was optimized out, revert to the old behavior. */
> if (! value_optimized_out (value))
> {
> diff --git a/gdb/jv-exp.y b/gdb/jv-exp.y
> index 2e6de6f..bbdb330 100644
> --- a/gdb/jv-exp.y
> +++ b/gdb/jv-exp.y
> @@ -1284,9 +1284,7 @@ push_variable (struct parser_state *par_state, struct stoken name)
> }
>
> write_exp_elt_opcode (par_state, OP_VAR_VALUE);
> - /* We want to use the selected frame, not another more inner frame
> - which happens to be in the same block. */
> - write_exp_elt_block (par_state, NULL);
> + write_exp_elt_block (par_state, sym.block);
> write_exp_elt_sym (par_state, sym.symbol);
> write_exp_elt_opcode (par_state, OP_VAR_VALUE);
> return 1;
> diff --git a/gdb/language.h b/gdb/language.h
> index 2675b82..ea8442f 100644
> --- a/gdb/language.h
> +++ b/gdb/language.h
> @@ -241,13 +241,19 @@ struct language_defn
> void (*la_value_print) (struct value *, struct ui_file *,
> const struct value_print_options *);
>
> - /* Given a symbol VAR, and a stack frame id FRAME, read the value
> - of the variable an return (pointer to a) struct value containing
> - the value.
> + /* Given a symbol VAR, the corresponding block VAR_BLOCK (if any) and a
> + stack frame id FRAME, read the value of the variable and return (pointer
> + to a) struct value containing the value.
> +
> + VAR_BLOCK is needed if there's a possibility for VAR to be outside
> + FRAME. This is what happens if FRAME correspond to a nested function
> + and VAR is defined in the outer function. If callers know that VAR is
> + located in FRAME, NULL can be passed as VAR_BLOCK.
====
"If callers know that VAR is located in FRAME or is global, ..." ?
>
> Throw an error if the variable cannot be found. */
>
> struct value *(*la_read_var_value) (struct symbol *var,
> + const struct block *var_block,
> struct frame_info *frame);
>
> /* PC is possibly an unknown languages trampoline.
> diff --git a/gdb/m2-exp.y b/gdb/m2-exp.y
> index a203218..5c5652e 100644
> --- a/gdb/m2-exp.y
> +++ b/gdb/m2-exp.y
> @@ -636,10 +636,7 @@ variable: NAME
> }
>
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> - /* We want to use the selected frame, not
> - another more inner frame which happens to
> - be in the same block. */
> - write_exp_elt_block (pstate, NULL);
> + write_exp_elt_block (pstate, sym.block);
> write_exp_elt_sym (pstate, sym.symbol);
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> }
> diff --git a/gdb/objfiles.c b/gdb/objfiles.c
> index c6f9f00..95b4a97 100644
> --- a/gdb/objfiles.c
> +++ b/gdb/objfiles.c
> @@ -199,6 +199,77 @@ set_objfile_main_name (struct objfile *objfile,
> objfile->per_bfd->language_of_main = lang;
> }
>
> +/* Helper structure to map blocks to static link properties in hash tables. */
> +
> +struct static_link_htab_entry
> +{
> + const struct block *block;
> + struct dynamic_prop *static_link;
====
It's too bad this isn't const struct dynamic_prop *static_link;
I'm guessing it can't be that without fixing some laxness elsewhere
(which I wouldn't impose on this patch), but can you check?
> +};
> +
> +/* Return whether P1 (a struct static_link_htab_entry *) is a mapping from P2
> + (a struct block *). */
> +
> +static int
> +static_link_htab_entry_eq (const void *p1, const void *p2)
> +{
> + const struct static_link_htab_entry *entry
> + = (const struct static_link_htab_entry *) p1;
> + const struct block *block = (const struct block *) p2;
====
blank line here
Also, this is a non-standard implementation of an htab eq function.
Generally both p1 and p2 point to an element in the hash table.
I see hashtab.h has this:
/* Compare a table entry with a possible entry. The entry already in
the table always comes first, so the second element can be of a
different type (but in this case htab_find and htab_find_slot
cannot be used; instead the variants that accept a hash value
must be used). */
typedef int (*htab_eq) (const void *, const void *);
so this eq function is possibly ok, except I also see calls to
htab_find,htab_find_slot below. AIUC, one of these needs to change.
> + return block == entry->block;
> +}
> +
> +/* Register STATIC_LINK as the static link for BLOCK, which is part of OBJFILE.
> + Must not be called more than once for each BLOCK. */
> +
> +void
> +objfile_register_static_link (struct objfile *objfile,
> + const struct block *block,
> + struct dynamic_prop *static_link)
> +{
> + void **slot;
> + struct static_link_htab_entry *entry;
> +
> + if (objfile->static_links == NULL)
> + objfile->static_links = htab_create_alloc
> + (1, htab_hash_pointer, static_link_htab_entry_eq, NULL,
> + xcalloc, xfree);
> +
> + /* Create a slot for the mapping, make sure it's the first mapping for this
> + block and then create the mapping itself. */
> + slot = htab_find_slot (objfile->static_links, block, INSERT);
> + gdb_assert (*slot == NULL);
> +
> + entry = (struct static_link_htab_entry *) obstack_alloc
> + (&objfile->objfile_obstack, sizeof (*entry));
> + entry->block = block;
> + entry->static_link = static_link;
> + *slot = (void *) entry;
> +}
> +
> +/* Look for a static link for BLOCK, which is part of OBJFILE. Return NULL if
> + none was found. */
> +
> +struct dynamic_prop *
> +objfile_lookup_static_link (struct objfile *objfile,
> + const struct block *block)
> +{
> + struct static_link_htab_entry *entry;
> +
> + if (objfile->static_links == NULL)
> + return NULL;
> + entry
> + = (struct static_link_htab_entry *) htab_find (objfile->static_links,
> + block);
> + if (entry == NULL)
> + return NULL;
> + else
====
I don't know how others feel, but "else" clauses in particular situations
like this are just noise. How about removing it?
> + {
> + gdb_assert (entry->block == block);
> + return entry->static_link;
> + }
> +}
> +
>
>
> /* Called via bfd_map_over_sections to build up the section table that
> @@ -653,6 +724,11 @@ free_objfile (struct objfile *objfile)
> /* Rebuild section map next time we need it. */
> get_objfile_pspace_data (objfile->pspace)->section_map_dirty = 1;
>
> + /* Free the map for static links. There's no need to free static link
> + themselves since they were allocated on the objstack. */
> + if (objfile->static_links != NULL)
> + htab_delete (objfile->static_links);
> +
> /* The last thing we do is free the objfile struct itself. */
> xfree (objfile);
> }
> diff --git a/gdb/objfiles.h b/gdb/objfiles.h
> index a0dc69b..aa2e966 100644
> --- a/gdb/objfiles.h
> +++ b/gdb/objfiles.h
> @@ -20,6 +20,7 @@
> #if !defined (OBJFILES_H)
> #define OBJFILES_H
>
> +#include "hashtab.h"
> #include "gdb_obstack.h" /* For obstack internals. */
> #include "symfile.h" /* For struct psymbol_allocation_list. */
> #include "progspace.h"
> @@ -412,6 +413,16 @@ struct objfile
> table, so we have to keep them here to relocate them
> properly. */
> struct symbol *template_symbols;
> +
> + /* Associate a static link (struct dynamic_prop *) to all blocks (struct
> + block *) that have one. For nested functions, the static link is the
> + expression that computes the frame base of the lexically enclosing
> + function.
> +
> + Very few blocks have a static link, so it's more memory efficient to
> + store these here. Static links must be allocated on the objfile's
> + obstack. */
> + struct htab *static_links;
====
s/struct htab */htab_t /
> };
>
> /* Defines for the objfile flag word. */
> @@ -719,4 +730,11 @@ extern const char *objfile_debug_name (const struct objfile *objfile);
> extern void set_objfile_main_name (struct objfile *objfile,
> const char *name, enum language lang);
>
> +extern void objfile_register_static_link (struct objfile *objfile,
> + const struct block *block,
> + struct dynamic_prop *static_link);
> +
> +extern struct dynamic_prop *objfile_lookup_static_link
> + (struct objfile *objfile, const struct block *block);
> +
> #endif /* !defined (OBJFILES_H) */
> diff --git a/gdb/p-exp.y b/gdb/p-exp.y
> index a2f86d6..173d9fb 100644
> --- a/gdb/p-exp.y
> +++ b/gdb/p-exp.y
> @@ -769,10 +769,7 @@ variable: name_not_typename
> }
>
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> - /* We want to use the selected frame, not
> - another more inner frame which happens to
> - be in the same block. */
> - write_exp_elt_block (pstate, NULL);
> + write_exp_elt_block (pstate, sym.block);
> write_exp_elt_sym (pstate, sym.symbol);
> write_exp_elt_opcode (pstate, OP_VAR_VALUE);
> current_type = sym.symbol->type; }
> diff --git a/gdb/printcmd.c b/gdb/printcmd.c
> index f51e25c..553cc71 100644
> --- a/gdb/printcmd.c
> +++ b/gdb/printcmd.c
> @@ -1988,7 +1988,11 @@ print_variable_and_value (const char *name, struct symbol *var,
> struct value *val;
> struct value_print_options opts;
>
> - val = read_var_value (var, frame);
> + /* READ_VAR_VALUE needs a block in order to deal with non-local
> + references (i.e. to handle nested functions). In this context, we
> + print variables that are local to this frame, so we can avoid passing
> + a block to it. */
> + val = read_var_value (var, NULL, frame);
> get_user_print_options (&opts);
> opts.deref_ref = 1;
> common_val_print (val, stream, indent, &opts, current_language);
> diff --git a/gdb/python/py-finishbreakpoint.c b/gdb/python/py-finishbreakpoint.c
> index e3d4867..345642e 100644
> --- a/gdb/python/py-finishbreakpoint.c
> +++ b/gdb/python/py-finishbreakpoint.c
> @@ -265,7 +265,7 @@ bpfinishpy_init (PyObject *self, PyObject *args, PyObject *kwargs)
> /* Ignore Python errors at this stage. */
> self_bpfinish->return_type = type_to_type_object (ret_type);
> PyErr_Clear ();
> - func_value = read_var_value (function, frame);
> + func_value = read_var_value (function, NULL, frame);
> self_bpfinish->function_value =
> value_to_value_object (func_value);
> PyErr_Clear ();
> diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
> index 7290056..fa7937a 100644
> --- a/gdb/python/py-frame.c
> +++ b/gdb/python/py-frame.c
> @@ -504,6 +504,7 @@ frapy_read_var (PyObject *self, PyObject *args)
> struct frame_info *frame;
> PyObject *sym_obj, *block_obj = NULL;
> struct symbol *var = NULL; /* gcc-4.3.2 false warning. */
> + const struct block *block = NULL;
> struct value *val = NULL;
>
> if (!PyArg_ParseTuple (args, "O|O", &sym_obj, &block_obj))
> @@ -514,7 +515,6 @@ frapy_read_var (PyObject *self, PyObject *args)
> else if (gdbpy_is_string (sym_obj))
> {
> char *var_name;
> - const struct block *block = NULL;
> struct cleanup *cleanup;
>
> var_name = python_string_to_target_string (sym_obj);
> @@ -536,11 +536,14 @@ frapy_read_var (PyObject *self, PyObject *args)
>
> TRY
> {
> + struct symbol_in_block lookup_sym;
> FRAPY_REQUIRE_VALID (self, frame);
>
> if (!block)
> block = get_frame_block (frame, NULL);
> - var = lookup_symbol (var_name, block, VAR_DOMAIN, NULL).symbol;
> + lookup_sym = lookup_symbol (var_name, block, VAR_DOMAIN, NULL);
> + var = lookup_sym.symbol;
> + block = lookup_sym.block;
> }
> CATCH (except, RETURN_MASK_ALL)
> {
> @@ -572,7 +575,7 @@ frapy_read_var (PyObject *self, PyObject *args)
> {
> FRAPY_REQUIRE_VALID (self, frame);
>
> - val = read_var_value (var, frame);
> + val = read_var_value (var, block, frame);
> }
> CATCH (except, RETURN_MASK_ALL)
> {
> diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
> index e3336b1..397ac86 100644
> --- a/gdb/python/py-framefilter.c
> +++ b/gdb/python/py-framefilter.c
> @@ -43,16 +43,17 @@ enum mi_print_types
> NAME is a pass-through argument where the name of the symbol will
> be written. NAME is allocated in this function, but the caller is
> responsible for clean up. SYM is a pass-through argument where the
> - symbol will be written. In the case of the API returning a string,
> - this will be set to NULL. LANGUAGE is also a pass-through argument
> - denoting the language attributed to the Symbol. In the case of SYM
> - being NULL, this will be set to the current language. Returns
> - EXT_LANG_BT_ERROR on error with the appropriate Python exception set, and
> - EXT_LANG_BT_OK on success. */
> + symbol will be written and SYM_BLOCK is a pass-through argument to
> + write the block where the symbol lies in. In the case of the API
> + returning a string, this will be set to NULL. LANGUAGE is also a
> + pass-through argument denoting the language attributed to the
> + Symbol. In the case of SYM being NULL, this will be set to the
> + current language. Returns EXT_LANG_BT_ERROR on error with the
> + appropriate Python exception set, and EXT_LANG_BT_OK on success. */
>
> static enum ext_lang_bt_status
> extract_sym (PyObject *obj, char **name, struct symbol **sym,
> - const struct language_defn **language)
> + struct block **sym_block, const struct language_defn **language)
> {
> PyObject *result = PyObject_CallMethod (obj, "symbol", NULL);
>
> @@ -75,12 +76,17 @@ extract_sym (PyObject *obj, char **name, struct symbol **sym,
> python_language. */
> *language = python_language;
> *sym = NULL;
> + *sym_block = NULL;
> }
> else
> {
> /* This type checks 'result' during the conversion so we
> just call it unconditionally and check the return. */
> *sym = symbol_object_to_symbol (result);
> + /* TODO: How should we find the corresponding block for this symbol?
> + Should we lookup all blocks in the owning objfile? Should we store
> + the bloc kin the Symbol object? */
> + *sym_block = NULL;
>
> Py_DECREF (result);
>
> @@ -537,10 +543,11 @@ enumerate_args (PyObject *iter,
> const struct language_defn *language;
> char *sym_name;
> struct symbol *sym;
> + struct block *sym_block;
> struct value *val;
> enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
>
> - success = extract_sym (item, &sym_name, &sym, &language);
> + success = extract_sym (item, &sym_name, &sym, &sym_block, &language);
> if (success == EXT_LANG_BT_ERROR)
> {
> Py_DECREF (item);
> @@ -736,12 +743,13 @@ enumerate_locals (PyObject *iter,
> struct value *val;
> enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
> struct symbol *sym;
> + struct block *sym_block;
> int local_indent = 8 + (8 * indent);
> struct cleanup *locals_cleanups;
>
> locals_cleanups = make_cleanup_py_decref (item);
>
> - success = extract_sym (item, &sym_name, &sym, &language);
> + success = extract_sym (item, &sym_name, &sym, &sym_block, &language);
> if (success == EXT_LANG_BT_ERROR)
> {
> do_cleanups (locals_cleanups);
> @@ -769,7 +777,7 @@ enumerate_locals (PyObject *iter,
> {
> TRY
> {
> - val = read_var_value (sym, frame);
> + val = read_var_value (sym, sym_block, frame);
> }
> CATCH (except, RETURN_MASK_ERROR)
> {
> diff --git a/gdb/python/py-symbol.c b/gdb/python/py-symbol.c
> index 401e7e9..b58e59d 100644
> --- a/gdb/python/py-symbol.c
> +++ b/gdb/python/py-symbol.c
> @@ -278,7 +278,10 @@ sympy_value (PyObject *self, PyObject *args)
> if (symbol_read_needs_frame (symbol) && frame_info == NULL)
> error (_("symbol requires a frame to compute its value"));
>
> - value = read_var_value (symbol, frame_info);
> + /* TODO: How should we find the corresponding block for this symbol?
> + Should we lookup all blocks in the owning objfile? Should we store
> + the block in the Symbol object? */
> + value = read_var_value (symbol, NULL, frame_info);
> }
> CATCH (except, RETURN_MASK_ALL)
> {
> diff --git a/gdb/stack.c b/gdb/stack.c
> index b4cfdbd..5a18a06 100644
> --- a/gdb/stack.c
> +++ b/gdb/stack.c
> @@ -318,7 +318,7 @@ read_frame_local (struct symbol *sym, struct frame_info *frame,
>
> TRY
> {
> - argp->val = read_var_value (sym, frame);
> + argp->val = read_var_value (sym, NULL, frame);
> }
> CATCH (except, RETURN_MASK_ERROR)
> {
> @@ -344,7 +344,7 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
> {
> TRY
> {
> - val = read_var_value (sym, frame);
> + val = read_var_value (sym, NULL, frame);
> }
> CATCH (except, RETURN_MASK_ERROR)
> {
> @@ -471,7 +471,7 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
>
> TRY
> {
> - val = read_var_value (sym, frame);
> + val = read_var_value (sym, NULL, frame);
> }
> CATCH (except, RETURN_MASK_ERROR)
> {
> @@ -2424,7 +2424,7 @@ return_command (char *retval_exp, int from_tty)
> value_fetch_lazy (return_value);
>
> if (thisfun != NULL)
> - function = read_var_value (thisfun, thisframe);
> + function = read_var_value (thisfun, NULL, thisframe);
>
> rv_conv = RETURN_VALUE_REGISTER_CONVENTION;
> if (TYPE_CODE (return_type) == TYPE_CODE_VOID)
> diff --git a/gdb/symtab.h b/gdb/symtab.h
> index 73026b3..509537b 100644
> --- a/gdb/symtab.h
> +++ b/gdb/symtab.h
> @@ -665,6 +665,24 @@ struct symbol_block_ops
> uninitialized in such case. */
> void (*find_frame_base_location) (struct symbol *framefunc, CORE_ADDR pc,
> const gdb_byte **start, size_t *length);
> +
> + /* Return the frame base address. FRAME is the frame for which we want to
> + compute the base address while FRAMEFUNC is the symbol for the
> + corresponding function.
> +
> + This method is designed to work with static links (nested functions
> + handling). Static links are function properties whose evaluation return
====
s/return/returns/
> + the frame base address for the enclosing frame. However, there are
> + multiple definitions for "frame base": the content of the frame base
> + register, the CFA as defined by DWARF unwinding information, ...
> +
> + So this specific method is supposed to compute the frame base address such
> + as for nested fuctions, the static link computes the same address. For
> + instance, considering DWARF debugging information, the static link is
> + computed with DW_AT_static_link and this method must be used to compute
> + the corresponding DW_AT_frame_base attribute. */
> + CORE_ADDR (*get_frame_base) (struct symbol *framefunc,
> + struct frame_info *frame);
> };
>
> /* Functions used with LOC_REGISTER and LOC_REGPARM_ADDR. */
> diff --git a/gdb/testsuite/gdb.base/nested-subp1.c b/gdb/testsuite/gdb.base/nested-subp1.c
> new file mode 100644
> index 0000000..967eb2f
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp1.c
> @@ -0,0 +1,37 @@
> +/* This test program is part of GDB, the GNU debugger.
> +
> + Copyright 2015 Free Software Foundation, Inc.
> +
> + This program is free software; you can redistribute it and/or modify
> + it under the terms of the GNU General Public License as published by
> + the Free Software Foundation; either version 3 of the License, or
> + (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
> +
> +int
> +foo (int i1)
> +{
> + int
> + nested (int i2)
> + {
> + /* Here with i1 and i2, we can test that GDB can fetch both a local and a
> + non-local variable in the most simple nested function situation: the
> + parent block instance is accessible as the directly upper frame. */
> + return i1 * i2; /* STOP */
> + }
> +
> + return nested (i1 + 1);
> +}
> +
> +int
> +main ()
> +{
> + return !foo (1);
> +}
> diff --git a/gdb/testsuite/gdb.base/nested-subp1.exp b/gdb/testsuite/gdb.base/nested-subp1.exp
> new file mode 100644
> index 0000000..9720f5b
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp1.exp
> @@ -0,0 +1,55 @@
> +# Copyright 2015 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
> +
> +# This file is part of the gdb testsuite.
> +
> +#
> +# Test nested functions related functionality.
> +#
> +
> +standard_testfile
> +
> +
> +set testcase "nested-subp1"
> +
> +if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
> + [standard_output_file "${testcase}"] \
> + "${testcase}" \
> + [list debug "additional_flags=-std=gnu99"]] != "" } {
> + return -1
> +}
> +
> +
> +# Run until the variables we are interested in are visible.
> +
> +clean_restart "${testcase}"
> +if ![runto_main] {
> + perror "could not run to main"
> + continue
> +}
> +
> +set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
> +gdb_test "break ${testcase}.c:${bp_location}" \
> + "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
> + "breakpoint to the STOP marker"
> +gdb_test "continue" \
> + "Breakpoint \[0-9\]+, nested .*" \
> + "continue to the STOP marker"
> +
> +
> +# Check we get correct values for both local and non-local variable references.
> +
> +gdb_test "print i1" "1"
> +gdb_test "print i2" "2"
> diff --git a/gdb/testsuite/gdb.base/nested-subp2.c b/gdb/testsuite/gdb.base/nested-subp2.c
> new file mode 100644
> index 0000000..a6449e34
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp2.c
> @@ -0,0 +1,48 @@
> +/* This test program is part of GDB, the GNU debugger.
> +
> + Copyright 2015 Free Software Foundation, Inc.
> +
> + This program is free software; you can redistribute it and/or modify
> + it under the terms of the GNU General Public License as published by
> + the Free Software Foundation; either version 3 of the License, or
> + (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
> +
> +void
> +iter_str (const char *str, void (*callback) (char c))
> +{
> + for (; *str != '\0'; ++str)
> + callback (*str);
> +}
> +
> +int
> +length_str (const char *str)
> +{
> + int count = 0;
> +
> + void
> + increment (char c)
> + {
> + /* Here with COUNT, we can test that GDB can read a non-local variable even
> + though it's not directly in the upper stack frame. */
> + count += 1; /* STOP */
> + }
> +
> + iter_str (str, &increment);
> + return count;
> +}
> +
> +int
> +main ()
> +{
> + if (length_str ("foo") == 3)
> + return 0;
> + return 1;
> +}
> diff --git a/gdb/testsuite/gdb.base/nested-subp2.exp b/gdb/testsuite/gdb.base/nested-subp2.exp
> new file mode 100644
> index 0000000..a107d1c
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp2.exp
> @@ -0,0 +1,64 @@
> +# Copyright 2015 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
> +
> +# This file is part of the gdb testsuite.
> +
> +#
> +# Test nested functions related functionality.
> +#
> +
> +standard_testfile
> +
> +
> +set testcase "nested-subp2"
> +
> +if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
> + [standard_output_file "${testcase}"] \
> + "${testcase}" \
> + [list debug "additional_flags=-std=gnu99"]] != "" } {
> + return -1
> +}
> +
> +
> +# Run until the variables we are interested in are visible.
> +
> +clean_restart "${testcase}"
> +if ![runto_main] {
> + perror "could not run to main"
> + continue
> +}
> +
> +set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
> +gdb_test "break ${testcase}.c:${bp_location}" \
> + "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
> + "breakpoint to the STOP marker"
> +gdb_test "continue" \
> + "Breakpoint \[0-9\]+, increment .*" \
> + "continue to the STOP marker"
> +
> +
> +# Check we get correct values for both local and non-local variable references.
> +
> +gdb_test "print c" "102 'f'"
> +gdb_test "print count" "0"
> +
> +
> +# Same but a little later: make sure we were looking at the proper places.
> +
> +gdb_test "continue" \
> + "Breakpoint \[0-9\]+, increment .*" \
> + "continue to the STOP marker"
> +gdb_test "print c" "111 'o'"
> +gdb_test "print count" "1"
> diff --git a/gdb/testsuite/gdb.base/nested-subp3.c b/gdb/testsuite/gdb.base/nested-subp3.c
> new file mode 100644
> index 0000000..a51f417
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp3.c
> @@ -0,0 +1,66 @@
> +/* This test program is part of GDB, the GNU debugger.
> +
> + Copyright 2015 Free Software Foundation, Inc.
> +
> + This program is free software; you can redistribute it and/or modify
> + it under the terms of the GNU General Public License as published by
> + the Free Software Foundation; either version 3 of the License, or
> + (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <http://www.gnu.org/licenses/>. */
> +
> +#include <stdlib.h>
> +
> +typedef void (*callback_t) (void);
> +
> +extern void process (callback_t cb);
> +extern void parent (int first, callback_t cb);
> +
> +void
> +ignore (int unused)
> +{
> + (void) unused;
> +}
> +
> +void
> +process (callback_t cb)
> +{
> + parent (0, cb);
> +}
> +
> +void
> +parent (int first, callback_t cb)
> +{
> + void child (void)
> + {
> + /* When reaching this, there are two block instances for PARENT on the
> + stack: the one that is right in the upper frame is not the one actually
> + used for non-local references, so GDB has to follow the static link in
> + order to get the correct instance, and thus in order to read the proper
> + variables.
> +
> + As a simple check, we can verify that under GDB, the following is true:
> + parent_first == first (which should be one: see the IF block below). */
> + const int parent_first = first;
> + ignore (parent_first); /* STOP */
> + ignore (first);
> + }
> +
> + if (first)
> + process (&child);
> + else
> + cb ();
> +}
> +
> +int
> +main ()
> +{
> + parent (1, NULL);
> + return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/nested-subp3.exp b/gdb/testsuite/gdb.base/nested-subp3.exp
> new file mode 100644
> index 0000000..8f9b522
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/nested-subp3.exp
> @@ -0,0 +1,55 @@
> +# Copyright 2015 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program. If not, see <http://www.gnu.org/licenses/>.
> +
> +# This file is part of the gdb testsuite.
> +
> +#
> +# Test nested functions related functionality.
> +#
> +
> +standard_testfile
> +
> +
> +set testcase "nested-subp3"
> +
> +if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
> + [standard_output_file "${testcase}"] \
> + "${testcase}" \
> + [list debug "additional_flags=-std=gnu99"]] != "" } {
> + return -1
> +}
> +
> +
> +# Run until the variables we are interested in are visible.
> +
> +clean_restart "${testcase}"
> +if ![runto_main] {
> + perror "could not run to main"
> + continue
> +}
> +
> +set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
> +gdb_test "break ${testcase}.c:${bp_location}" \
> + "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
> + "breakpoint to the STOP marker"
> +gdb_test "continue" \
> + "Breakpoint \[0-9\]+, child .*" \
> + "continue to the STOP marker"
> +
> +
> +# Check we get correct values for both local and non-local variable references.
> +
> +gdb_test "print first" "1"
> +gdb_test "print parent_first" "1"
> diff --git a/gdb/valops.c b/gdb/valops.c
> index d326f93..94182c5 100644
> --- a/gdb/valops.c
> +++ b/gdb/valops.c
> @@ -1288,27 +1288,12 @@ value_repeat (struct value *arg1, int count)
> struct value *
> value_of_variable (struct symbol *var, const struct block *b)
> {
> - struct frame_info *frame;
> + struct frame_info *frame = NULL;
>
> - if (!symbol_read_needs_frame (var))
> - frame = NULL;
> - else if (!b)
> + if (symbol_read_needs_frame (var))
> frame = get_selected_frame (_("No frame selected."));
> - else
> - {
> - frame = block_innermost_frame (b);
> - if (!frame)
> - {
> - if (BLOCK_FUNCTION (b) && !block_inlined_p (b)
> - && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)))
> - error (_("No frame is currently executing in block %s."),
> - SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)));
> - else
> - error (_("No frame is currently executing in specified block"));
> - }
> - }
>
> - return read_var_value (var, frame);
> + return read_var_value (var, b, frame);
> }
>
> struct value *
> @@ -3459,9 +3444,9 @@ value_struct_elt_for_reference (struct type *domain, int offset,
> return NULL;
>
> if (want_address)
> - return value_addr (read_var_value (s, 0));
> + return value_addr (read_var_value (s, 0, 0));
> else
> - return read_var_value (s, 0);
> + return read_var_value (s, 0, 0);
> }
>
> if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
> @@ -3489,7 +3474,7 @@ value_struct_elt_for_reference (struct type *domain, int offset,
> if (s == NULL)
> return NULL;
>
> - v = read_var_value (s, 0);
> + v = read_var_value (s, 0, 0);
> if (!want_address)
> result = v;
> else
> @@ -3725,7 +3710,7 @@ value_full_object (struct value *argp,
> struct value *
> value_of_this (const struct language_defn *lang)
> {
> - struct symbol *sym;
> + struct symbol_in_block sym;
> const struct block *b;
> struct frame_info *frame;
>
> @@ -3736,12 +3721,12 @@ value_of_this (const struct language_defn *lang)
>
> b = get_frame_block (frame, NULL);
>
> - sym = lookup_language_this (lang, b).symbol;
> - if (sym == NULL)
> + sym = lookup_language_this (lang, b);
> + if (sym.symbol == NULL)
> error (_("current stack frame does not contain a variable named `%s'"),
> lang->la_name_of_this);
>
> - return read_var_value (sym, frame);
> + return read_var_value (sym.symbol, sym.block, frame);
> }
>
> /* Return the value of the local variable, if one exists. Return NULL
> diff --git a/gdb/value.h b/gdb/value.h
> index 7ff6aa8..c35a876 100644
> --- a/gdb/value.h
> +++ b/gdb/value.h
> @@ -670,9 +670,11 @@ struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
> extern int symbol_read_needs_frame (struct symbol *);
>
> extern struct value *read_var_value (struct symbol *var,
> + const struct block *var_block,
> struct frame_info *frame);
>
> extern struct value *default_read_var_value (struct symbol *var,
> + const struct block *var_block,
> struct frame_info *frame);
>
> extern struct value *allocate_value (struct type *type);
> diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
> index b5b2a1d..dea24a4 100644
> --- a/gdb/xcoffread.c
> +++ b/gdb/xcoffread.c
> @@ -1388,8 +1388,8 @@ read_xcoff_symtab (struct objfile *objfile, struct partial_symtab *pst)
> break;
> }
>
> - finish_block (newobj->name, &local_symbols, newobj->old_blocks,
> - newobj->start_addr,
> + finish_block (newobj->name, NULL, &local_symbols,
> + newobj->old_blocks, newobj->start_addr,
> (fcn_cs_saved.c_value
> + fcn_aux_saved.x_sym.x_misc.x_fsize
> + ANOFFSET (objfile->section_offsets,
From 2e65051fd50bb99985bbc2c8ed13c67514e9cc08 Mon Sep 17 00:00:00 2001
From: Pierre-Marie de Rodat <derodat@adacore.com>
Date: Thu, 5 Feb 2015 17:00:06 +0100
Subject: [PATCH] DWARF: handle non-local references in nested functions
GDB's current behavior when dealing with non-local references in the
context of nested fuctions is approximative:
- code using valops.c:value_of_variable read the first available stack
frame that holds the corresponding variable (whereas there can be
multiple candidates for this);
- code directly relying on read_var_value will instead read non-local
variables in frames where they are not even defined.
This change adds the necessary context to symbol reads (to get the block
they belong to) and to blocks (the static link property, if any) so that
GDB can make the proper decisions when dealing with non-local varibale
references.
gdb/ChangeLog:
* ada-lang.c (ada_read_var_value): Add a VAR_BLOCK argument and pass
it to default_read_var_value.
* block.c (block_static_link): New accessor.
* block.h (block_static_link): Declare it.
* buildsym.c (finish_block_internal): Add a static_link
argument. If there is a static link, associate it to the new
block.
(finish_block): Add a static link argument and pass it to
finish_block_internal.
(end_symtab_get_static_block): Update calls to finish_block and
to finish_block_internal.
(end_symtab_with_blockvector): Update call to
finish_block_internal.
* buildsym.h: Forward-declare struct dynamic_prop.
(struct context_stack): Add a static_link field.
(finish_block): Add a static link argument.
* c-exp.y: Remove an obsolete
comment (evaluation of variables already start from the selected
frame, and now they climb *up* the call stack) and propagate the
block information to the produced expression.
* d-exp.y: Likewise.
* f-exp.y: Likewise.
* go-exp.y: Likewise.
* jv-exp.y: Likewise.
* m2-exp.y: Likewise.
* p-exp.y: Likewise.
* coffread.c (coff_symtab_read): Update calls to finish_block.
* dbxread.c (process_one_symbol): Likewise.
* xcoffread.c (read_xcoff_symtab): Likewise.
* compile/compile-c-symbols.c (convert_one_symbol): Add a
VAR_BLOCK parameter and pass it to calls to read_var_value.
(convert_symbol_sym): Pass the block corresponding to SYM to the
call to convert_one_symbol.
* compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Update
call to read_var_value.
* dwarf2loc.c (block_op_get_frame_base): New.
(dwarf2_block_frame_base_locexpr_funcs): Implement the
get_frame_base method.
(dwarf2_block_frame_base_loclist_funcs): Likewise.
(dwarf2locexpr_baton_eval): Add a frame argument and use it
instead of the selected frame in order to evaluate the
expression.
(dwarf2_evaluate_property): Add a frame argument. Update call
to dwarf2_locexpr_baton_eval to provide a frame in available and
to handle the absence of address stack.
* dwarf2loc.h (dwarf2_evaluate_property): Add a frame argument.
* dwarf2read.c (attr_to_dynamic_prop): Add a forward
declaration.
(read_func_scope): Record any available static link description.
Update call to finish_block.
(read_lexical_block_scope): Update call to finish_block.
* findvar.c (follow_static_link): New.
(get_hosting_frame): New.
(default_read_var_value): Add a VAR_BLOCK argument. Use
get_hosting_frame to handle non-local references.
(read_var_value): Add a VAR_BLOCK argument and pass it to the
LA_READ_VAR_VALUE method.
* gdbtypes.c (resolve_dynamic_range): Update calls to
dwarf2_evaluate_property.
(resolve_dynamic_type_internal): Likewise.
* infcmd.c (finish_command_continuation): Update call to
read_var_value, passing it the block coming from symbol lookup.
* infrun.c (insert_exception_resume_breakpoint): Likewise.
* language.h (struct language_defn): Add a VAR_BLOCK argument to
the LA_READ_VAR_VALUE method.
* objfiles.c (objfile_register_static_link): New.
(objfile_lookup_static_link): New.
(free_objfile): Free the STATIC_LINKS hashed map if needed.
* objfiles.h: Include hashtab.h.
(struct objfile): Add a STATIC_LINKS field.
(objfile_register_static_link): New.
(objfile_lookup_static_link): New.
* printcmd.c (print_variable_and_value): Update call to
read_var_value.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-frame.c (frapy_read_var): Update call to
read_var_value, passing it the block coming from symbol lookup.
* python/py-framefilter.c (extract_sym): Add a SYM_BLOCK
parameter and set the pointed value to NULL (TODO).
(enumerate_args): Update call to extract_sym.
(enumerate_locals): Update calls to extract_sym and to
read_var_value.
* python/py-symbol.c (sympy_value): Update call to
read_var_value (TODO).
* stack.c (read_frame_local): Update call to read_var_value.
(read_frame_arg): Likewise.
(return_command): Likewise.
* symtab.h (struct symbol_block_ops): Add a get_frame_base
method.
(struct symbol): Add a block field.
(SYMBOL_BLOCK): New accessor.
* valops.c (value_of_variable): Remove frame/block handling and
pass the block argument to read_var_value, which does this job
now.
(value_struct_elt_for_reference): Update calls to
read_var_value.
(value_of_this): Pass the block found to read_var_value.
* value.h (read_var_value): Add a VAR_BLOCK argument.
(default_read_var_value): Likewise.
gdb/testsuite/ChangeLog:
* gdb.base/nested-subp1.exp: New file.
* gdb.base/nested-subp1.c: New file.
* gdb.base/nested-subp2.exp: New file.
* gdb.base/nested-subp2.c: New file.
* gdb.base/nested-subp3.exp: New file.
* gdb.base/nested-subp3.c: New file.
---
gdb/ada-lang.c | 5 +-
gdb/block.c | 15 +++
gdb/block.h | 6 ++
gdb/buildsym.c | 17 ++--
gdb/buildsym.h | 14 ++-
gdb/c-exp.y | 5 +-
gdb/coffread.c | 4 +-
gdb/compile/compile-c-symbols.c | 19 ++--
gdb/compile/compile-loc2c.c | 2 +-
gdb/d-exp.y | 4 +-
gdb/dbxread.c | 8 +-
gdb/dwarf2loc.c | 52 ++++++++--
gdb/dwarf2loc.h | 11 ++-
gdb/dwarf2read.c | 19 +++-
gdb/f-exp.y | 5 +-
gdb/findvar.c | 168 +++++++++++++++++++++++++++++++-
gdb/gdbtypes.c | 7 +-
gdb/go-exp.y | 5 +-
gdb/infcmd.c | 2 +-
gdb/infrun.c | 7 +-
gdb/jv-exp.y | 4 +-
gdb/language.h | 12 ++-
gdb/m2-exp.y | 5 +-
gdb/objfiles.c | 76 +++++++++++++++
gdb/objfiles.h | 18 ++++
gdb/p-exp.y | 5 +-
gdb/printcmd.c | 6 +-
gdb/python/py-finishbreakpoint.c | 2 +-
gdb/python/py-frame.c | 9 +-
gdb/python/py-framefilter.c | 28 ++++--
gdb/python/py-symbol.c | 5 +-
gdb/stack.c | 8 +-
gdb/symtab.h | 18 ++++
gdb/testsuite/gdb.base/nested-subp1.c | 37 +++++++
gdb/testsuite/gdb.base/nested-subp1.exp | 55 +++++++++++
gdb/testsuite/gdb.base/nested-subp2.c | 48 +++++++++
gdb/testsuite/gdb.base/nested-subp2.exp | 64 ++++++++++++
gdb/testsuite/gdb.base/nested-subp3.c | 66 +++++++++++++
gdb/testsuite/gdb.base/nested-subp3.exp | 55 +++++++++++
gdb/valops.c | 35 ++-----
gdb/value.h | 2 +
gdb/xcoffread.c | 4 +-
42 files changed, 810 insertions(+), 127 deletions(-)
create mode 100644 gdb/testsuite/gdb.base/nested-subp1.c
create mode 100644 gdb/testsuite/gdb.base/nested-subp1.exp
create mode 100644 gdb/testsuite/gdb.base/nested-subp2.c
create mode 100644 gdb/testsuite/gdb.base/nested-subp2.exp
create mode 100644 gdb/testsuite/gdb.base/nested-subp3.c
create mode 100644 gdb/testsuite/gdb.base/nested-subp3.exp
@@ -13750,7 +13750,8 @@ ada_get_symbol_name_cmp (const char *lookup_name)
/* Implement the "la_read_var_value" language_defn method for Ada. */
static struct value *
-ada_read_var_value (struct symbol *var, struct frame_info *frame)
+ada_read_var_value (struct symbol *var, const struct block *var_block,
+ struct frame_info *frame)
{
const struct block *frame_block = NULL;
struct symbol *renaming_sym = NULL;
@@ -13766,7 +13767,7 @@ ada_read_var_value (struct symbol *var, struct frame_info *frame)
/* This is a typical case where we expect the default_read_var_value
function to work. */
- return default_read_var_value (var, frame);
+ return default_read_var_value (var, var_block, frame);
}
const struct language_defn ada_language_defn = {
@@ -428,6 +428,21 @@ set_block_compunit_symtab (struct block *block, struct compunit_symtab *cu)
gb->compunit_symtab = cu;
}
+/* See block.h. */
+
+struct dynamic_prop *
+block_static_link (const struct block *block)
+{
+ struct objfile *objfile = block_objfile (block);
+
+ /* Only objfile-owned blocks that materialize top function scopes can have
+ static links. */
+ if (objfile == NULL || BLOCK_FUNCTION (block) == NULL)
+ return NULL;
+
+ return (struct dynamic_prop *) objfile_lookup_static_link (objfile, block);
+}
+
/* Return the compunit of the global block. */
static struct compunit_symtab *
@@ -190,6 +190,12 @@ extern struct block *allocate_global_block (struct obstack *obstack);
extern void set_block_compunit_symtab (struct block *,
struct compunit_symtab *);
+/* Return a property to evaluate the static link associated to BLOCK. Note
+ that only objfile-owned and function-level blocks can have a static link.
+ Return NULL if there is no such property. */
+
+extern struct dynamic_prop *block_static_link (const struct block *block);
+
/* A block iterator. This structure should be treated as though it
were opaque; it is only defined here because we want to support
stack allocation of iterators. */
@@ -331,7 +331,8 @@ free_pending_blocks (void)
file). Put the block on the list of pending blocks. */
static struct block *
-finish_block_internal (struct symbol *symbol, struct pending **listhead,
+finish_block_internal (struct symbol *symbol, struct dynamic_prop *static_link,
+ struct pending **listhead,
struct pending_block *old_blocks,
CORE_ADDR start, CORE_ADDR end,
int is_global, int expandable)
@@ -422,6 +423,9 @@ finish_block_internal (struct symbol *symbol, struct pending **listhead,
BLOCK_FUNCTION (block) = NULL;
}
+ if (static_link != NULL)
+ objfile_register_static_link (objfile, block, static_link);
+
/* Now "free" the links of the list, and empty the list. */
for (next = *listhead; next; next = next1)
@@ -512,11 +516,12 @@ finish_block_internal (struct symbol *symbol, struct pending **listhead,
}
struct block *
-finish_block (struct symbol *symbol, struct pending **listhead,
+finish_block (struct symbol *symbol, struct dynamic_prop *static_link,
+ struct pending **listhead,
struct pending_block *old_blocks,
CORE_ADDR start, CORE_ADDR end)
{
- return finish_block_internal (symbol, listhead, old_blocks,
+ return finish_block_internal (symbol, static_link, listhead, old_blocks,
start, end, 0, 0);
}
@@ -1218,7 +1223,7 @@ end_symtab_get_static_block (CORE_ADDR end_addr, int expandable, int required)
struct context_stack *cstk = pop_context ();
/* Make a block for the local symbols within. */
- finish_block (cstk->name, &local_symbols, cstk->old_blocks,
+ finish_block (cstk->name, NULL, &local_symbols, cstk->old_blocks,
cstk->start_addr, end_addr);
if (context_stack_depth > 0)
@@ -1289,7 +1294,7 @@ end_symtab_get_static_block (CORE_ADDR end_addr, int expandable, int required)
else
{
/* Define the STATIC_BLOCK. */
- return finish_block_internal (NULL, &file_symbols, NULL,
+ return finish_block_internal (NULL, NULL, &file_symbols, NULL,
last_source_start_addr, end_addr,
0, expandable);
}
@@ -1317,7 +1322,7 @@ end_symtab_with_blockvector (struct block *static_block,
end_addr = BLOCK_END (static_block);
/* Create the GLOBAL_BLOCK and build the blockvector. */
- finish_block_internal (NULL, &global_symbols, NULL,
+ finish_block_internal (NULL, NULL, &global_symbols, NULL,
last_source_start_addr, end_addr,
1, expandable);
blockvector = make_blockvector ();
@@ -39,6 +39,8 @@ struct compunit_symtab;
struct block;
struct pending_block;
+struct dynamic_prop;
+
#ifndef EXTERN
#define EXTERN extern
#endif
@@ -141,6 +143,11 @@ struct context_stack
struct symbol *name;
+ /* Expression that computes the frame base of the lexically enclosing
+ function, if any. NULL otherwise. */
+
+ struct dynamic_prop *static_link;
+
/* PC where this context starts */
CORE_ADDR start_addr;
@@ -192,9 +199,10 @@ extern struct symbol *find_symbol_in_list (struct pending *list,
char *name, int length);
extern struct block *finish_block (struct symbol *symbol,
- struct pending **listhead,
- struct pending_block *old_blocks,
- CORE_ADDR start, CORE_ADDR end);
+ struct dynamic_prop *static_link,
+ struct pending **listhead, struct
+ pending_block *old_blocks, CORE_ADDR start,
+ CORE_ADDR end);
extern void record_block_range (struct block *,
CORE_ADDR start, CORE_ADDR end_inclusive);
@@ -1070,10 +1070,7 @@ variable: name_not_typename
}
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
- /* We want to use the selected frame, not
- another more inner frame which happens to
- be in the same block. */
- write_exp_elt_block (pstate, NULL);
+ write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
}
@@ -1144,7 +1144,7 @@ coff_symtab_read (long symtab_offset, unsigned int nsyms,
enter_linenos (fcn_line_ptr, fcn_first_line,
fcn_last_line, objfile);
- finish_block (newobj->name, &local_symbols,
+ finish_block (newobj->name, NULL, &local_symbols,
newobj->old_blocks, newobj->start_addr,
fcn_cs_saved.c_value
+ fcn_aux_saved.x_sym.x_misc.x_fsize
@@ -1188,7 +1188,7 @@ coff_symtab_read (long symtab_offset, unsigned int nsyms,
cs->c_value + ANOFFSET (objfile->section_offsets,
SECT_OFF_TEXT (objfile));
/* Make a block for the local symbols within. */
- finish_block (0, &local_symbols, newobj->old_blocks,
+ finish_block (0, NULL, &local_symbols, newobj->old_blocks,
newobj->start_addr, tmpaddr);
}
/* Now pop locals of block just finished. */
@@ -134,16 +134,16 @@ symbol_substitution_name (struct symbol *sym)
return concat ("__", SYMBOL_NATURAL_NAME (sym), "_ptr", (char *) NULL);
}
-/* Convert a given symbol, SYM, to the compiler's representation.
- CONTEXT is the compiler instance. IS_GLOBAL is true if the
- symbol came from the global scope. IS_LOCAL is true if the symbol
- came from a local scope. (Note that the two are not strictly
- inverses because the symbol might have come from the static
- scope.) */
+/* Convert a given symbol, SYM (located in VAR_BLOCK, if any), to the
+ compiler's representation. CONTEXT is the compiler instance. IS_GLOBAL is
+ true if the symbol came from the global scope. IS_LOCAL is true if the
+ symbol came from a local scope. (Note that the two are not strictly
+ inverses because the symbol might have come from the static scope.) */
static void
convert_one_symbol (struct compile_c_instance *context,
struct symbol *sym,
+ const struct block *var_block,
int is_global,
int is_local)
{
@@ -247,7 +247,7 @@ convert_one_symbol (struct compile_c_instance *context,
SYMBOL_PRINT_NAME (sym));
}
- val = read_var_value (sym, frame);
+ val = read_var_value (sym, var_block, frame);
if (VALUE_LVAL (val) != lval_memory)
error (_("Symbol \"%s\" cannot be used for compilation "
"evaluation as its address has not been found."),
@@ -339,7 +339,8 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
fprintf_unfiltered (gdb_stdlog,
"gcc_convert_symbol \"%s\": global symbol\n",
identifier);
- convert_one_symbol (context, global_sym.symbol, 1, 0);
+ convert_one_symbol (context, global_sym.symbol, global_sym.block, 1,
+ 0);
}
}
@@ -347,7 +348,7 @@ convert_symbol_sym (struct compile_c_instance *context, const char *identifier,
fprintf_unfiltered (gdb_stdlog,
"gcc_convert_symbol \"%s\": local symbol\n",
identifier);
- convert_one_symbol (context, sym, 0, is_local_symbol);
+ convert_one_symbol (context, sym, block, 0, is_local_symbol);
}
/* Convert a minimal symbol to its gcc form. CONTEXT is the compiler
@@ -636,7 +636,7 @@ do_compile_dwarf_expr_to_c (int indent, struct ui_file *stream,
"there is no selected frame"),
SYMBOL_PRINT_NAME (sym));
- val = read_var_value (sym, frame);
+ val = read_var_value (sym, NULL, frame);
if (VALUE_LVAL (val) != lval_memory)
error (_("Symbol \"%s\" cannot be used for compilation evaluation "
"as its address has not been found."),
@@ -1066,9 +1066,7 @@ push_variable (struct parser_state *ps, struct stoken name)
}
write_exp_elt_opcode (ps, OP_VAR_VALUE);
- /* We want to use the selected frame, not another more inner frame
- which happens to be in the same block. */
- write_exp_elt_block (ps, NULL);
+ write_exp_elt_block (ps, sym.block);
write_exp_elt_sym (ps, sym.symbol);
write_exp_elt_opcode (ps, OP_VAR_VALUE);
return 1;
@@ -2766,8 +2766,8 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
newobj = pop_context ();
/* Make a block for the local symbols within. */
- block = finish_block (newobj->name, &local_symbols,
- newobj->old_blocks,
+ block = finish_block (newobj->name, NULL,
+ &local_symbols, newobj->old_blocks,
newobj->start_addr, newobj->start_addr + valu);
/* For C++, set the block's scope. */
@@ -2868,7 +2868,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
newobj->start_addr = valu;
}
/* Make a block for the local symbols within. */
- finish_block (0, &local_symbols, newobj->old_blocks,
+ finish_block (0, NULL, &local_symbols, newobj->old_blocks,
newobj->start_addr, valu);
}
}
@@ -3165,7 +3165,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
newobj = pop_context ();
/* Make a block for the local symbols within. */
- block = finish_block (newobj->name, &local_symbols,
+ block = finish_block (newobj->name, NULL, &local_symbols,
newobj->old_blocks, newobj->start_addr,
valu);
@@ -381,12 +381,42 @@ locexpr_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
*start = symbaton->data;
}
+/* Implement the struct symbol_block_ops::get_frame_base method. */
+
+static CORE_ADDR
+block_op_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
+{
+ if (SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location != NULL)
+ {
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct type *type = builtin_type (gdbarch)->builtin_data_ptr;
+ struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (framefunc);
+ const gdb_byte *start;
+ size_t length;
+ struct value *result;
+
+ SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
+ (framefunc, get_frame_pc (frame), &start, &length);
+ result = dwarf2_evaluate_loc_desc (type, frame, start, length,
+ dlbaton->per_cu);
+
+ /* The DW_AT_frame_base attribute contains a location description which
+ computes the base address itself. However, the call to
+ dwarf2_evaluate_loc_desc returns a value representing a variable at
+ that address. The frame base address is thus this variable's
+ address. */
+ return value_address (result);
+ }
+ return 0;
+}
+
/* Vector for inferior functions as represented by LOC_BLOCK, if the inferior
function uses DWARF expression for its DW_AT_frame_base. */
const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs =
{
- locexpr_find_frame_base_location
+ locexpr_find_frame_base_location,
+ block_op_get_frame_base
};
/* Implement find_frame_base_location method for LOC_BLOCK functions using
@@ -406,7 +436,8 @@ loclist_find_frame_base_location (struct symbol *framefunc, CORE_ADDR pc,
const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs =
{
- loclist_find_frame_base_location
+ loclist_find_frame_base_location,
+ block_op_get_frame_base
};
/* See dwarf2loc.h. */
@@ -2396,13 +2427,14 @@ dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
}
/* Evaluates a dwarf expression and stores the result in VAL, expecting
- that the dwarf expression only produces a single CORE_ADDR. ADDR is a
- context (location of a variable) and might be needed to evaluate the
- location expression.
+ that the dwarf expression only produces a single CORE_ADDR. FRAME is the
+ frame in which the expression is evaluated. ADDR is a context (location of
+ a variable) and might be needed to evaluate the location expression.
Returns 1 on success, 0 otherwise. */
static int
dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
+ struct frame_info *frame,
CORE_ADDR addr,
CORE_ADDR *valp)
{
@@ -2417,7 +2449,7 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
ctx = new_dwarf_expr_context ();
cleanup = make_cleanup_free_dwarf_expr_context (ctx);
- baton.frame = get_selected_frame (NULL);
+ baton.frame = frame;
baton.per_cu = dlbaton->per_cu;
baton.obj_address = addr;
@@ -2461,19 +2493,24 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
int
dwarf2_evaluate_property (const struct dynamic_prop *prop,
+ struct frame_info *frame,
struct property_addr_info *addr_stack,
CORE_ADDR *value)
{
if (prop == NULL)
return 0;
+ if (frame == NULL && has_stack_frames ())
+ frame = get_selected_frame (NULL);
+
switch (prop->kind)
{
case PROP_LOCEXPR:
{
const struct dwarf2_property_baton *baton = prop->data.baton;
- if (dwarf2_locexpr_baton_eval (&baton->locexpr, addr_stack->addr,
+ if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
+ addr_stack ? addr_stack->addr : 0,
value))
{
if (baton->referenced_type)
@@ -2490,7 +2527,6 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
case PROP_LOCLIST:
{
struct dwarf2_property_baton *baton = prop->data.baton;
- struct frame_info *frame = get_selected_frame (NULL);
CORE_ADDR pc = get_frame_address_in_block (frame);
const gdb_byte *data;
struct value *val;
@@ -122,12 +122,19 @@ struct property_addr_info
struct property_addr_info *next;
};
-/* Converts a dynamic property into a static one. ADDR_STACK is the stack
- of addresses that might be needed to evaluate the property.
+/* Converts a dynamic property into a static one. FRAME is the frame in which
+ the property is evaluated; if NULL, the selected frame (if any) is used
+ instead.
+
+ ADDR_STACK is the stack of addresses that might be needed to evaluate the
+ property. When evaluating a property that is not related to a type, it can
+ be NULL.
+
Returns 1 if PROP could be converted and the static value is passed back
into VALUE, otherwise returns 0. */
int dwarf2_evaluate_property (const struct dynamic_prop *prop,
+ struct frame_info *frame,
struct property_addr_info *addr_stack,
CORE_ADDR *value);
@@ -1736,6 +1736,10 @@ static void load_full_type_unit (struct dwarf2_per_cu_data *per_cu);
static void read_signatured_type (struct signatured_type *);
+static int attr_to_dynamic_prop (const struct attribute *attr,
+ struct die_info *die, struct dwarf2_cu *cu,
+ struct dynamic_prop *prop);
+
/* memory allocation interface */
static struct dwarf_block *dwarf_alloc_block (struct dwarf2_cu *);
@@ -11393,6 +11397,16 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
if (attr)
dwarf2_symbol_mark_computed (attr, newobj->name, cu, 1);
+ /* If there is a location for the static link, record it. */
+ newobj->static_link = NULL;
+ attr = dwarf2_attr (die, DW_AT_static_link, cu);
+ if (attr)
+ {
+ newobj->static_link = obstack_alloc (&objfile->objfile_obstack,
+ sizeof (*newobj->static_link));
+ attr_to_dynamic_prop (attr, die, cu, newobj->static_link);
+ }
+
cu->list_in_scope = &local_symbols;
if (die->child != NULL)
@@ -11443,7 +11457,8 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
newobj = pop_context ();
/* Make a block for the local symbols within. */
- block = finish_block (newobj->name, &local_symbols, newobj->old_blocks,
+ block = finish_block (newobj->name, newobj->static_link,
+ &local_symbols, newobj->old_blocks,
lowpc, highpc);
/* For C++, set the block's scope. */
@@ -11529,7 +11544,7 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
if (local_symbols != NULL || using_directives != NULL)
{
struct block *block
- = finish_block (0, &local_symbols, newobj->old_blocks,
+ = finish_block (0, NULL, &local_symbols, newobj->old_blocks,
newobj->start_addr, highpc);
/* Note that recording ranges after traversing children, as we
@@ -521,10 +521,7 @@ variable: name_not_typename
innermost_block = sym.block;
}
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
- /* We want to use the selected frame, not
- another more inner frame which happens to
- be in the same block. */
- write_exp_elt_block (pstate, NULL);
+ write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
break;
@@ -32,6 +32,7 @@
#include "block.h"
#include "objfiles.h"
#include "language.h"
+#include "dwarf2loc.h"
/* Basic byte-swapping routines. All 'extract' functions return a
host-format integer from a target-format integer at ADDR which is
@@ -409,11 +410,166 @@ minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data)
return (data->result.minsym != NULL);
}
+/* Given static link expression and the frame it lives in, look for the frame
+ the static links points to and return it. Return NULL if we could not find
+ such a frame. */
+
+static struct frame_info *
+follow_static_link (struct frame_info *frame,
+ const struct dynamic_prop *static_link)
+{
+ CORE_ADDR upper_frame_base;
+
+ if (!dwarf2_evaluate_property (static_link, frame, NULL, &upper_frame_base))
+ return NULL;
+
+ /* Now climb up the stack frame until we reach the frame we are interested
+ in. */
+ for (; frame != NULL; frame = get_prev_frame (frame))
+ {
+ struct symbol *framefunc = get_frame_function (frame);
+
+ /* Protect ourselves against bad things such as circular call stacks. */
+ QUIT;
+
+ /* If we don't know how to compute FRAME's base address, don't give up:
+ maybe the frame we are looking for is upper in the stace frame. */
+ if (framefunc != NULL
+ && SYMBOL_BLOCK_OPS (framefunc)->get_frame_base
+ && (SYMBOL_BLOCK_OPS (framefunc)->get_frame_base (framefunc, frame)
+ == upper_frame_base))
+ break;
+ }
+
+ return frame;
+}
+
+/* Assuming VAR is a symbol that can be reached from FRAME thanks to lexical
+ rules, look for the frame that is actually hosting VAR and return it. If,
+ for some reason, we found no such frame, return NULL.
+
+ This kind of computation is necessary to correctly handle lexically nested
+ functions.
+
+ Note that in some cases, we know what scope VAR comes from but we cannot
+ reach the specific frame that hosts the instance of VAR we are looking for.
+ For backward compatibility purposes (with old compilers), we then look for
+ the first frame that can host it. */
+
+static struct frame_info *
+get_hosting_frame (struct symbol *var, const struct block *var_block,
+ struct frame_info *frame)
+{
+ const struct block *frame_block = NULL;
+
+ if (!symbol_read_needs_frame (var))
+ return NULL;
+
+ /* Some symbols for local variables have no block: this happens when they are
+ not produced by a debug information reader, for instance when GDB creates
+ synthetic symbols. Without block information, we must assume they are
+ local to FRAME. In this case, there is nothing to do. */
+ else if (var_block == NULL)
+ return frame;
+
+ /* We currently assume that all symbols with a location list need a frame.
+ This is true in practice because selecting the location description
+ requires to compute the CFA, hence requires a frame. However we have
+ tests that embed global/static symbols with null location lists.
+ We want to get <optimized out> instead of <frame required> when evaluating
+ them so return a frame instead of raising an error. */
+ else if (var_block == block_global_block (var_block)
+ || var_block == block_static_block (var_block))
+ return frame;
+
+ /* We have to handle the "my_func::my_local_var" notation. This requires us
+ to look for upper frames when we find no block for the current frame: here
+ and below, handle when frame_block == NULL. */
+ if (frame != NULL)
+ frame_block = get_frame_block (frame, NULL);
+
+ /* Climb up the call stack until reaching the frame we are looking for. */
+ while (frame != NULL && frame_block != var_block)
+ {
+ /* Protect ourselves against bad things such as circular call stacks. */
+ QUIT;
+
+ if (frame_block == NULL)
+ {
+ frame = get_prev_frame (frame);
+ if (frame == NULL)
+ break;
+ frame_block = get_frame_block (frame, NULL);
+ }
+
+ /* If we failed to find the proper frame, fallback to the heuristic
+ method below. */
+ else if (frame_block == block_global_block (frame_block))
+ {
+ frame = NULL;
+ break;
+ }
+
+ /* Assuming we have a block for this frame: if we are at the function
+ level, the immediate upper lexical block is in an outer function:
+ follow the static link. */
+ else if (BLOCK_FUNCTION (frame_block))
+ {
+ const struct dynamic_prop *static_link
+ = block_static_link (frame_block);
+ int could_climb_up = 0;
+
+ if (static_link != NULL)
+ {
+ frame = follow_static_link (frame, static_link);
+ if (frame != NULL)
+ {
+ frame_block = get_frame_block (frame, NULL);
+ could_climb_up = frame_block != NULL;
+ }
+ }
+ if (!could_climb_up)
+ {
+ frame = NULL;
+ break;
+ }
+ }
+
+ else
+ /* We must be in some function nested lexical block. Just get the
+ outer block: both must share the same frame. */
+ frame_block = BLOCK_SUPERBLOCK (frame_block);
+ }
+
+ /* Old compilers may not provide a static link, or they may provide an
+ invalid one. For such cases, fallback on the old way to evaluate
+ non-local references: just climb up the call stack and pick the first
+ frame that contains the variable we are looking for. */
+ if (frame == NULL)
+ {
+ frame = block_innermost_frame (var_block);
+ if (!frame)
+ {
+ if (BLOCK_FUNCTION (var_block)
+ && !block_inlined_p (var_block)
+ && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)))
+ error (_("No frame is currently executing in block %s."),
+ SYMBOL_PRINT_NAME (BLOCK_FUNCTION (var_block)));
+ else
+ error (_("No frame is currently executing in specified"
+ " block"));
+ }
+ }
+
+ return frame;
+}
+
/* A default implementation for the "la_read_var_value" hook in
the language vector which should work in most situations. */
struct value *
-default_read_var_value (struct symbol *var, struct frame_info *frame)
+default_read_var_value (struct symbol *var, const struct block *var_block,
+ struct frame_info *frame)
{
struct value *v;
struct type *type = SYMBOL_TYPE (var);
@@ -427,7 +583,10 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
check_typedef (type);
if (symbol_read_needs_frame (var))
- gdb_assert (frame);
+ gdb_assert (frame != NULL);
+
+ if (frame != NULL)
+ frame = get_hosting_frame (var, var_block, frame);
if (SYMBOL_COMPUTED_OPS (var) != NULL)
return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame);
@@ -610,14 +769,15 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
/* Calls VAR's language la_read_var_value hook with the given arguments. */
struct value *
-read_var_value (struct symbol *var, struct frame_info *frame)
+read_var_value (struct symbol *var, const struct block *var_block,
+ struct frame_info *frame)
{
const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var));
gdb_assert (lang != NULL);
gdb_assert (lang->la_read_var_value != NULL);
- return lang->la_read_var_value (var, frame);
+ return lang->la_read_var_value (var, var_block, frame);
}
/* Install default attributes for register values. */
@@ -1874,7 +1874,7 @@ resolve_dynamic_range (struct type *dyn_range_type,
gdb_assert (TYPE_CODE (dyn_range_type) == TYPE_CODE_RANGE);
prop = &TYPE_RANGE_DATA (dyn_range_type)->low;
- if (dwarf2_evaluate_property (prop, addr_stack, &value))
+ if (dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
{
low_bound.kind = PROP_CONST;
low_bound.data.const_val = value;
@@ -1886,7 +1886,7 @@ resolve_dynamic_range (struct type *dyn_range_type,
}
prop = &TYPE_RANGE_DATA (dyn_range_type)->high;
- if (dwarf2_evaluate_property (prop, addr_stack, &value))
+ if (dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
{
high_bound.kind = PROP_CONST;
high_bound.data.const_val = value;
@@ -2128,7 +2128,8 @@ resolve_dynamic_type_internal (struct type *type,
/* Resolve data_location attribute. */
prop = TYPE_DATA_LOCATION (resolved_type);
- if (prop != NULL && dwarf2_evaluate_property (prop, addr_stack, &value))
+ if (prop != NULL
+ && dwarf2_evaluate_property (prop, NULL, addr_stack, &value))
{
TYPE_DYN_PROP_ADDR (prop) = value;
TYPE_DYN_PROP_KIND (prop) = PROP_CONST;
@@ -611,10 +611,7 @@ variable: name_not_typename
}
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
- /* We want to use the selected frame, not
- another more inner frame which happens to
- be in the same block. */
- write_exp_elt_block (pstate, NULL);
+ write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
}
@@ -1660,7 +1660,7 @@ finish_command_continuation (void *arg, int err)
{
struct value *func;
- func = read_var_value (a->function, get_current_frame ());
+ func = read_var_value (a->function, NULL, get_current_frame ());
TRY
{
/* print_return_value can throw an exception in some
@@ -6082,14 +6082,13 @@ insert_exception_resume_breakpoint (struct thread_info *tp,
{
TRY
{
- struct symbol *vsym;
+ struct symbol_in_block vsym;
struct value *value;
CORE_ADDR handler;
struct breakpoint *bp;
- vsym = lookup_symbol (SYMBOL_LINKAGE_NAME (sym), b, VAR_DOMAIN,
- NULL).symbol;
- value = read_var_value (vsym, frame);
+ vsym = lookup_symbol (SYMBOL_LINKAGE_NAME (sym), b, VAR_DOMAIN, NULL);
+ value = read_var_value (vsym.symbol, vsym.block, frame);
/* If the value was optimized out, revert to the old behavior. */
if (! value_optimized_out (value))
{
@@ -1284,9 +1284,7 @@ push_variable (struct parser_state *par_state, struct stoken name)
}
write_exp_elt_opcode (par_state, OP_VAR_VALUE);
- /* We want to use the selected frame, not another more inner frame
- which happens to be in the same block. */
- write_exp_elt_block (par_state, NULL);
+ write_exp_elt_block (par_state, sym.block);
write_exp_elt_sym (par_state, sym.symbol);
write_exp_elt_opcode (par_state, OP_VAR_VALUE);
return 1;
@@ -241,13 +241,19 @@ struct language_defn
void (*la_value_print) (struct value *, struct ui_file *,
const struct value_print_options *);
- /* Given a symbol VAR, and a stack frame id FRAME, read the value
- of the variable an return (pointer to a) struct value containing
- the value.
+ /* Given a symbol VAR, the corresponding block VAR_BLOCK (if any) and a
+ stack frame id FRAME, read the value of the variable and return (pointer
+ to a) struct value containing the value.
+
+ VAR_BLOCK is needed if there's a possibility for VAR to be outside
+ FRAME. This is what happens if FRAME correspond to a nested function
+ and VAR is defined in the outer function. If callers know that VAR is
+ located in FRAME, NULL can be passed as VAR_BLOCK.
Throw an error if the variable cannot be found. */
struct value *(*la_read_var_value) (struct symbol *var,
+ const struct block *var_block,
struct frame_info *frame);
/* PC is possibly an unknown languages trampoline.
@@ -636,10 +636,7 @@ variable: NAME
}
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
- /* We want to use the selected frame, not
- another more inner frame which happens to
- be in the same block. */
- write_exp_elt_block (pstate, NULL);
+ write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
}
@@ -199,6 +199,77 @@ set_objfile_main_name (struct objfile *objfile,
objfile->per_bfd->language_of_main = lang;
}
+/* Helper structure to map blocks to static link properties in hash tables. */
+
+struct static_link_htab_entry
+{
+ const struct block *block;
+ struct dynamic_prop *static_link;
+};
+
+/* Return whether P1 (a struct static_link_htab_entry *) is a mapping from P2
+ (a struct block *). */
+
+static int
+static_link_htab_entry_eq (const void *p1, const void *p2)
+{
+ const struct static_link_htab_entry *entry
+ = (const struct static_link_htab_entry *) p1;
+ const struct block *block = (const struct block *) p2;
+ return block == entry->block;
+}
+
+/* Register STATIC_LINK as the static link for BLOCK, which is part of OBJFILE.
+ Must not be called more than once for each BLOCK. */
+
+void
+objfile_register_static_link (struct objfile *objfile,
+ const struct block *block,
+ struct dynamic_prop *static_link)
+{
+ void **slot;
+ struct static_link_htab_entry *entry;
+
+ if (objfile->static_links == NULL)
+ objfile->static_links = htab_create_alloc
+ (1, htab_hash_pointer, static_link_htab_entry_eq, NULL,
+ xcalloc, xfree);
+
+ /* Create a slot for the mapping, make sure it's the first mapping for this
+ block and then create the mapping itself. */
+ slot = htab_find_slot (objfile->static_links, block, INSERT);
+ gdb_assert (*slot == NULL);
+
+ entry = (struct static_link_htab_entry *) obstack_alloc
+ (&objfile->objfile_obstack, sizeof (*entry));
+ entry->block = block;
+ entry->static_link = static_link;
+ *slot = (void *) entry;
+}
+
+/* Look for a static link for BLOCK, which is part of OBJFILE. Return NULL if
+ none was found. */
+
+struct dynamic_prop *
+objfile_lookup_static_link (struct objfile *objfile,
+ const struct block *block)
+{
+ struct static_link_htab_entry *entry;
+
+ if (objfile->static_links == NULL)
+ return NULL;
+ entry
+ = (struct static_link_htab_entry *) htab_find (objfile->static_links,
+ block);
+ if (entry == NULL)
+ return NULL;
+ else
+ {
+ gdb_assert (entry->block == block);
+ return entry->static_link;
+ }
+}
+
/* Called via bfd_map_over_sections to build up the section table that
@@ -653,6 +724,11 @@ free_objfile (struct objfile *objfile)
/* Rebuild section map next time we need it. */
get_objfile_pspace_data (objfile->pspace)->section_map_dirty = 1;
+ /* Free the map for static links. There's no need to free static link
+ themselves since they were allocated on the objstack. */
+ if (objfile->static_links != NULL)
+ htab_delete (objfile->static_links);
+
/* The last thing we do is free the objfile struct itself. */
xfree (objfile);
}
@@ -20,6 +20,7 @@
#if !defined (OBJFILES_H)
#define OBJFILES_H
+#include "hashtab.h"
#include "gdb_obstack.h" /* For obstack internals. */
#include "symfile.h" /* For struct psymbol_allocation_list. */
#include "progspace.h"
@@ -412,6 +413,16 @@ struct objfile
table, so we have to keep them here to relocate them
properly. */
struct symbol *template_symbols;
+
+ /* Associate a static link (struct dynamic_prop *) to all blocks (struct
+ block *) that have one. For nested functions, the static link is the
+ expression that computes the frame base of the lexically enclosing
+ function.
+
+ Very few blocks have a static link, so it's more memory efficient to
+ store these here. Static links must be allocated on the objfile's
+ obstack. */
+ struct htab *static_links;
};
/* Defines for the objfile flag word. */
@@ -719,4 +730,11 @@ extern const char *objfile_debug_name (const struct objfile *objfile);
extern void set_objfile_main_name (struct objfile *objfile,
const char *name, enum language lang);
+extern void objfile_register_static_link (struct objfile *objfile,
+ const struct block *block,
+ struct dynamic_prop *static_link);
+
+extern struct dynamic_prop *objfile_lookup_static_link
+ (struct objfile *objfile, const struct block *block);
+
#endif /* !defined (OBJFILES_H) */
@@ -769,10 +769,7 @@ variable: name_not_typename
}
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
- /* We want to use the selected frame, not
- another more inner frame which happens to
- be in the same block. */
- write_exp_elt_block (pstate, NULL);
+ write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
current_type = sym.symbol->type; }
@@ -1988,7 +1988,11 @@ print_variable_and_value (const char *name, struct symbol *var,
struct value *val;
struct value_print_options opts;
- val = read_var_value (var, frame);
+ /* READ_VAR_VALUE needs a block in order to deal with non-local
+ references (i.e. to handle nested functions). In this context, we
+ print variables that are local to this frame, so we can avoid passing
+ a block to it. */
+ val = read_var_value (var, NULL, frame);
get_user_print_options (&opts);
opts.deref_ref = 1;
common_val_print (val, stream, indent, &opts, current_language);
@@ -265,7 +265,7 @@ bpfinishpy_init (PyObject *self, PyObject *args, PyObject *kwargs)
/* Ignore Python errors at this stage. */
self_bpfinish->return_type = type_to_type_object (ret_type);
PyErr_Clear ();
- func_value = read_var_value (function, frame);
+ func_value = read_var_value (function, NULL, frame);
self_bpfinish->function_value =
value_to_value_object (func_value);
PyErr_Clear ();
@@ -504,6 +504,7 @@ frapy_read_var (PyObject *self, PyObject *args)
struct frame_info *frame;
PyObject *sym_obj, *block_obj = NULL;
struct symbol *var = NULL; /* gcc-4.3.2 false warning. */
+ const struct block *block = NULL;
struct value *val = NULL;
if (!PyArg_ParseTuple (args, "O|O", &sym_obj, &block_obj))
@@ -514,7 +515,6 @@ frapy_read_var (PyObject *self, PyObject *args)
else if (gdbpy_is_string (sym_obj))
{
char *var_name;
- const struct block *block = NULL;
struct cleanup *cleanup;
var_name = python_string_to_target_string (sym_obj);
@@ -536,11 +536,14 @@ frapy_read_var (PyObject *self, PyObject *args)
TRY
{
+ struct symbol_in_block lookup_sym;
FRAPY_REQUIRE_VALID (self, frame);
if (!block)
block = get_frame_block (frame, NULL);
- var = lookup_symbol (var_name, block, VAR_DOMAIN, NULL).symbol;
+ lookup_sym = lookup_symbol (var_name, block, VAR_DOMAIN, NULL);
+ var = lookup_sym.symbol;
+ block = lookup_sym.block;
}
CATCH (except, RETURN_MASK_ALL)
{
@@ -572,7 +575,7 @@ frapy_read_var (PyObject *self, PyObject *args)
{
FRAPY_REQUIRE_VALID (self, frame);
- val = read_var_value (var, frame);
+ val = read_var_value (var, block, frame);
}
CATCH (except, RETURN_MASK_ALL)
{
@@ -43,16 +43,17 @@ enum mi_print_types
NAME is a pass-through argument where the name of the symbol will
be written. NAME is allocated in this function, but the caller is
responsible for clean up. SYM is a pass-through argument where the
- symbol will be written. In the case of the API returning a string,
- this will be set to NULL. LANGUAGE is also a pass-through argument
- denoting the language attributed to the Symbol. In the case of SYM
- being NULL, this will be set to the current language. Returns
- EXT_LANG_BT_ERROR on error with the appropriate Python exception set, and
- EXT_LANG_BT_OK on success. */
+ symbol will be written and SYM_BLOCK is a pass-through argument to
+ write the block where the symbol lies in. In the case of the API
+ returning a string, this will be set to NULL. LANGUAGE is also a
+ pass-through argument denoting the language attributed to the
+ Symbol. In the case of SYM being NULL, this will be set to the
+ current language. Returns EXT_LANG_BT_ERROR on error with the
+ appropriate Python exception set, and EXT_LANG_BT_OK on success. */
static enum ext_lang_bt_status
extract_sym (PyObject *obj, char **name, struct symbol **sym,
- const struct language_defn **language)
+ struct block **sym_block, const struct language_defn **language)
{
PyObject *result = PyObject_CallMethod (obj, "symbol", NULL);
@@ -75,12 +76,17 @@ extract_sym (PyObject *obj, char **name, struct symbol **sym,
python_language. */
*language = python_language;
*sym = NULL;
+ *sym_block = NULL;
}
else
{
/* This type checks 'result' during the conversion so we
just call it unconditionally and check the return. */
*sym = symbol_object_to_symbol (result);
+ /* TODO: How should we find the corresponding block for this symbol?
+ Should we lookup all blocks in the owning objfile? Should we store
+ the bloc kin the Symbol object? */
+ *sym_block = NULL;
Py_DECREF (result);
@@ -537,10 +543,11 @@ enumerate_args (PyObject *iter,
const struct language_defn *language;
char *sym_name;
struct symbol *sym;
+ struct block *sym_block;
struct value *val;
enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
- success = extract_sym (item, &sym_name, &sym, &language);
+ success = extract_sym (item, &sym_name, &sym, &sym_block, &language);
if (success == EXT_LANG_BT_ERROR)
{
Py_DECREF (item);
@@ -736,12 +743,13 @@ enumerate_locals (PyObject *iter,
struct value *val;
enum ext_lang_bt_status success = EXT_LANG_BT_ERROR;
struct symbol *sym;
+ struct block *sym_block;
int local_indent = 8 + (8 * indent);
struct cleanup *locals_cleanups;
locals_cleanups = make_cleanup_py_decref (item);
- success = extract_sym (item, &sym_name, &sym, &language);
+ success = extract_sym (item, &sym_name, &sym, &sym_block, &language);
if (success == EXT_LANG_BT_ERROR)
{
do_cleanups (locals_cleanups);
@@ -769,7 +777,7 @@ enumerate_locals (PyObject *iter,
{
TRY
{
- val = read_var_value (sym, frame);
+ val = read_var_value (sym, sym_block, frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
@@ -278,7 +278,10 @@ sympy_value (PyObject *self, PyObject *args)
if (symbol_read_needs_frame (symbol) && frame_info == NULL)
error (_("symbol requires a frame to compute its value"));
- value = read_var_value (symbol, frame_info);
+ /* TODO: How should we find the corresponding block for this symbol?
+ Should we lookup all blocks in the owning objfile? Should we store
+ the block in the Symbol object? */
+ value = read_var_value (symbol, NULL, frame_info);
}
CATCH (except, RETURN_MASK_ALL)
{
@@ -318,7 +318,7 @@ read_frame_local (struct symbol *sym, struct frame_info *frame,
TRY
{
- argp->val = read_var_value (sym, frame);
+ argp->val = read_var_value (sym, NULL, frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
@@ -344,7 +344,7 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
{
TRY
{
- val = read_var_value (sym, frame);
+ val = read_var_value (sym, NULL, frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
@@ -471,7 +471,7 @@ read_frame_arg (struct symbol *sym, struct frame_info *frame,
TRY
{
- val = read_var_value (sym, frame);
+ val = read_var_value (sym, NULL, frame);
}
CATCH (except, RETURN_MASK_ERROR)
{
@@ -2424,7 +2424,7 @@ return_command (char *retval_exp, int from_tty)
value_fetch_lazy (return_value);
if (thisfun != NULL)
- function = read_var_value (thisfun, thisframe);
+ function = read_var_value (thisfun, NULL, thisframe);
rv_conv = RETURN_VALUE_REGISTER_CONVENTION;
if (TYPE_CODE (return_type) == TYPE_CODE_VOID)
@@ -665,6 +665,24 @@ struct symbol_block_ops
uninitialized in such case. */
void (*find_frame_base_location) (struct symbol *framefunc, CORE_ADDR pc,
const gdb_byte **start, size_t *length);
+
+ /* Return the frame base address. FRAME is the frame for which we want to
+ compute the base address while FRAMEFUNC is the symbol for the
+ corresponding function.
+
+ This method is designed to work with static links (nested functions
+ handling). Static links are function properties whose evaluation return
+ the frame base address for the enclosing frame. However, there are
+ multiple definitions for "frame base": the content of the frame base
+ register, the CFA as defined by DWARF unwinding information, ...
+
+ So this specific method is supposed to compute the frame base address such
+ as for nested fuctions, the static link computes the same address. For
+ instance, considering DWARF debugging information, the static link is
+ computed with DW_AT_static_link and this method must be used to compute
+ the corresponding DW_AT_frame_base attribute. */
+ CORE_ADDR (*get_frame_base) (struct symbol *framefunc,
+ struct frame_info *frame);
};
/* Functions used with LOC_REGISTER and LOC_REGPARM_ADDR. */
new file mode 100644
@@ -0,0 +1,37 @@
+/* This test program is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+int
+foo (int i1)
+{
+ int
+ nested (int i2)
+ {
+ /* Here with i1 and i2, we can test that GDB can fetch both a local and a
+ non-local variable in the most simple nested function situation: the
+ parent block instance is accessible as the directly upper frame. */
+ return i1 * i2; /* STOP */
+ }
+
+ return nested (i1 + 1);
+}
+
+int
+main ()
+{
+ return !foo (1);
+}
new file mode 100644
@@ -0,0 +1,55 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+#
+# Test nested functions related functionality.
+#
+
+standard_testfile
+
+
+set testcase "nested-subp1"
+
+if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
+ [standard_output_file "${testcase}"] \
+ "${testcase}" \
+ [list debug "additional_flags=-std=gnu99"]] != "" } {
+ return -1
+}
+
+
+# Run until the variables we are interested in are visible.
+
+clean_restart "${testcase}"
+if ![runto_main] {
+ perror "could not run to main"
+ continue
+}
+
+set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
+gdb_test "break ${testcase}.c:${bp_location}" \
+ "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
+ "breakpoint to the STOP marker"
+gdb_test "continue" \
+ "Breakpoint \[0-9\]+, nested .*" \
+ "continue to the STOP marker"
+
+
+# Check we get correct values for both local and non-local variable references.
+
+gdb_test "print i1" "1"
+gdb_test "print i2" "2"
new file mode 100644
@@ -0,0 +1,48 @@
+/* This test program is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+void
+iter_str (const char *str, void (*callback) (char c))
+{
+ for (; *str != '\0'; ++str)
+ callback (*str);
+}
+
+int
+length_str (const char *str)
+{
+ int count = 0;
+
+ void
+ increment (char c)
+ {
+ /* Here with COUNT, we can test that GDB can read a non-local variable even
+ though it's not directly in the upper stack frame. */
+ count += 1; /* STOP */
+ }
+
+ iter_str (str, &increment);
+ return count;
+}
+
+int
+main ()
+{
+ if (length_str ("foo") == 3)
+ return 0;
+ return 1;
+}
new file mode 100644
@@ -0,0 +1,64 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+#
+# Test nested functions related functionality.
+#
+
+standard_testfile
+
+
+set testcase "nested-subp2"
+
+if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
+ [standard_output_file "${testcase}"] \
+ "${testcase}" \
+ [list debug "additional_flags=-std=gnu99"]] != "" } {
+ return -1
+}
+
+
+# Run until the variables we are interested in are visible.
+
+clean_restart "${testcase}"
+if ![runto_main] {
+ perror "could not run to main"
+ continue
+}
+
+set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
+gdb_test "break ${testcase}.c:${bp_location}" \
+ "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
+ "breakpoint to the STOP marker"
+gdb_test "continue" \
+ "Breakpoint \[0-9\]+, increment .*" \
+ "continue to the STOP marker"
+
+
+# Check we get correct values for both local and non-local variable references.
+
+gdb_test "print c" "102 'f'"
+gdb_test "print count" "0"
+
+
+# Same but a little later: make sure we were looking at the proper places.
+
+gdb_test "continue" \
+ "Breakpoint \[0-9\]+, increment .*" \
+ "continue to the STOP marker"
+gdb_test "print c" "111 'o'"
+gdb_test "print count" "1"
new file mode 100644
@@ -0,0 +1,66 @@
+/* This test program is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <stdlib.h>
+
+typedef void (*callback_t) (void);
+
+extern void process (callback_t cb);
+extern void parent (int first, callback_t cb);
+
+void
+ignore (int unused)
+{
+ (void) unused;
+}
+
+void
+process (callback_t cb)
+{
+ parent (0, cb);
+}
+
+void
+parent (int first, callback_t cb)
+{
+ void child (void)
+ {
+ /* When reaching this, there are two block instances for PARENT on the
+ stack: the one that is right in the upper frame is not the one actually
+ used for non-local references, so GDB has to follow the static link in
+ order to get the correct instance, and thus in order to read the proper
+ variables.
+
+ As a simple check, we can verify that under GDB, the following is true:
+ parent_first == first (which should be one: see the IF block below). */
+ const int parent_first = first;
+ ignore (parent_first); /* STOP */
+ ignore (first);
+ }
+
+ if (first)
+ process (&child);
+ else
+ cb ();
+}
+
+int
+main ()
+{
+ parent (1, NULL);
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,55 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+#
+# Test nested functions related functionality.
+#
+
+standard_testfile
+
+
+set testcase "nested-subp3"
+
+if { [gdb_compile "${srcdir}/${subdir}/${testcase}.c" \
+ [standard_output_file "${testcase}"] \
+ "${testcase}" \
+ [list debug "additional_flags=-std=gnu99"]] != "" } {
+ return -1
+}
+
+
+# Run until the variables we are interested in are visible.
+
+clean_restart "${testcase}"
+if ![runto_main] {
+ perror "could not run to main"
+ continue
+}
+
+set bp_location [gdb_get_line_number "STOP" "${testcase}.c"]
+gdb_test "break ${testcase}.c:${bp_location}" \
+ "Breakpoint \[0-9\]+ at 0x\[0-9a-fA-F\]+: .*" \
+ "breakpoint to the STOP marker"
+gdb_test "continue" \
+ "Breakpoint \[0-9\]+, child .*" \
+ "continue to the STOP marker"
+
+
+# Check we get correct values for both local and non-local variable references.
+
+gdb_test "print first" "1"
+gdb_test "print parent_first" "1"
@@ -1288,27 +1288,12 @@ value_repeat (struct value *arg1, int count)
struct value *
value_of_variable (struct symbol *var, const struct block *b)
{
- struct frame_info *frame;
+ struct frame_info *frame = NULL;
- if (!symbol_read_needs_frame (var))
- frame = NULL;
- else if (!b)
+ if (symbol_read_needs_frame (var))
frame = get_selected_frame (_("No frame selected."));
- else
- {
- frame = block_innermost_frame (b);
- if (!frame)
- {
- if (BLOCK_FUNCTION (b) && !block_inlined_p (b)
- && SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)))
- error (_("No frame is currently executing in block %s."),
- SYMBOL_PRINT_NAME (BLOCK_FUNCTION (b)));
- else
- error (_("No frame is currently executing in specified block"));
- }
- }
- return read_var_value (var, frame);
+ return read_var_value (var, b, frame);
}
struct value *
@@ -3459,9 +3444,9 @@ value_struct_elt_for_reference (struct type *domain, int offset,
return NULL;
if (want_address)
- return value_addr (read_var_value (s, 0));
+ return value_addr (read_var_value (s, 0, 0));
else
- return read_var_value (s, 0);
+ return read_var_value (s, 0, 0);
}
if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
@@ -3489,7 +3474,7 @@ value_struct_elt_for_reference (struct type *domain, int offset,
if (s == NULL)
return NULL;
- v = read_var_value (s, 0);
+ v = read_var_value (s, 0, 0);
if (!want_address)
result = v;
else
@@ -3725,7 +3710,7 @@ value_full_object (struct value *argp,
struct value *
value_of_this (const struct language_defn *lang)
{
- struct symbol *sym;
+ struct symbol_in_block sym;
const struct block *b;
struct frame_info *frame;
@@ -3736,12 +3721,12 @@ value_of_this (const struct language_defn *lang)
b = get_frame_block (frame, NULL);
- sym = lookup_language_this (lang, b).symbol;
- if (sym == NULL)
+ sym = lookup_language_this (lang, b);
+ if (sym.symbol == NULL)
error (_("current stack frame does not contain a variable named `%s'"),
lang->la_name_of_this);
- return read_var_value (sym, frame);
+ return read_var_value (sym.symbol, sym.block, frame);
}
/* Return the value of the local variable, if one exists. Return NULL
@@ -670,9 +670,11 @@ struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
extern int symbol_read_needs_frame (struct symbol *);
extern struct value *read_var_value (struct symbol *var,
+ const struct block *var_block,
struct frame_info *frame);
extern struct value *default_read_var_value (struct symbol *var,
+ const struct block *var_block,
struct frame_info *frame);
extern struct value *allocate_value (struct type *type);
@@ -1388,8 +1388,8 @@ read_xcoff_symtab (struct objfile *objfile, struct partial_symtab *pst)
break;
}
- finish_block (newobj->name, &local_symbols, newobj->old_blocks,
- newobj->start_addr,
+ finish_block (newobj->name, NULL, &local_symbols,
+ newobj->old_blocks, newobj->start_addr,
(fcn_cs_saved.c_value
+ fcn_aux_saved.x_sym.x_misc.x_fsize
+ ANOFFSET (objfile->section_offsets,
--
2.4.5