On Fri, 2022-07-15 at 21:08 +0530, Immad Mir wrote:
Thanks for the patch.
Various review comments:
The patch is missing a ChangeLog.
> ---
> gcc/analyzer/sm-fd.cc | 257 ++++++++++++++++++++++++---
> gcc/c-family/c-attribs.cc | 115 ++++++++++++
> gcc/doc/extend.texi | 19 ++
> gcc/testsuite/gcc.dg/analyzer/fd-5.c | 53 ++++++
> gcc/testsuite/gcc.dg/analyzer/fd-6.c | 14 ++
> 5 files changed, 431 insertions(+), 27 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/analyzer/fd-5.c
> create mode 100644 gcc/testsuite/gcc.dg/analyzer/fd-6.c
>
> diff --git a/gcc/analyzer/sm-fd.cc b/gcc/analyzer/sm-fd.cc
> index 8e4300b06e2..20018dfd12b 100644
> --- a/gcc/analyzer/sm-fd.cc
> +++ b/gcc/analyzer/sm-fd.cc
[...snip...]
> +enum fd_access_direction
> +{
> + DIR_READ_WRITE,
> + DIR_READ,
> + DIR_WRITE
> +};
Don't we already have DIR_READ and DIR_WRITE in enum access_direction
in analyzer.h? I wonder why this isn't an error due to the naming
collision?
The new enum refers to a *set* of valid access directions, so maybe
rename the new enum to "enum access_directions" (note the plural), and
rename the elements from DIR_ to DIRS_. Please carefully check all
usage of DIR_* in sm-fd.cc.
Maybe instead we should convert the values in enum access_direction
from indexes into bitfield masks.
[...snip...]
> @@ -317,19 +335,27 @@ public:
> bool
> emit (rich_location *rich_loc) final override
> {
> + bool warned;
> switch (m_fd_dir)
> {
> case DIR_READ:
> - return warning_at (rich_loc, get_controlling_option (),
> + warned = warning_at (rich_loc, get_controlling_option (),
> "%qE on %<read-only%> file descriptor %qE",
> m_callee_fndecl, m_arg);
> + break;
> case DIR_WRITE:
> - return warning_at (rich_loc, get_controlling_option (),
> + warned = warning_at (rich_loc, get_controlling_option (),
> "%qE on %<write-only%> file descriptor %qE",
> m_callee_fndecl, m_arg);
> + break;
...i.e. which DIR_READ/DIR_WRITE values are these cases using?
> default:
> gcc_unreachable ();
> }
> + if (warned && m_attr)
> + {
> + m_sm.inform_filedescriptor_attribute (m_callee_fndecl, m_arg_idx, m_fd_dir);
> + }
Redundant braces here ^^^
> + return warned;
> }
>
> bool
> @@ -359,8 +385,10 @@ public:
> }
>
> private:
> - enum access_direction m_fd_dir;
> + enum fd_access_direction m_fd_dir;
> const tree m_callee_fndecl;
> + bool m_attr;
> + int m_arg_idx;
> };
Most (all?) of the concrete subclasses seem to be adding the two fields
m_attr and m_arg_idx, so can you add them to class fd_diagnostic, or
introduce a common subclass, rather than repeating them in each
subclass?
I suspect the code would be simpler if inform_filedescriptor_attribute
were a method of fd_diagnostic, rather than of the state_machine: you
could move the (&& m_attr) part of the conditional into there, rather
than having every emit vfunc do the same test, and having to pass the
same fields to it each time (except perhaps the access dir?).
[...snip...]
> @@ -466,25 +510,29 @@ public:
> describe_final_event (const evdesc::final_event &ev) final override
> {
> if (m_first_close_event.known_p ())
> - return ev.formatted_print (
> - "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
> - m_arg, "close", &m_first_close_event);
> - else
> - return ev.formatted_print ("%qE on closed file descriptor %qE",
> - m_callee_fndecl, m_arg);
> + return ev.formatted_print (
> + "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
> + m_arg, "close", &m_first_close_event);
> + else
> + return ev.formatted_print ("%qE on closed file descriptor %qE",
> + m_callee_fndecl, m_arg);
What changed here? Is this just whitespace changes?
[...snip...]
> fd_state_machine::fd_state_machine (logger *logger)
> : state_machine ("file-descriptor", logger),
> m_constant_fd (add_state ("fd-constant")),
> @@ -647,11 +733,126 @@ fd_state_machine::on_stmt (sm_context *sm_ctxt, const supernode *node,
> on_read (sm_ctxt, node, stmt, call, callee_fndecl);
> return true;
> } // "read"
> +
> +
> + {
> + // Handle __attribute__((fd_arg))
> + bitmap argmap = get_fd_attrs ("fd_arg", callee_fndecl);
> + if (argmap)
> + check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, argmap, DIR_READ_WRITE);
> +
> + // Handle __attribute__((fd_arg_read))
> + bitmap read_argmap = get_fd_attrs ("fd_arg_read", callee_fndecl);
> + if(read_argmap)
> + check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, read_argmap, DIR_READ);
> +
> + // Handle __attribute__((fd_arg_write))
> + bitmap write_argmap = get_fd_attrs ("fd_arg_write", callee_fndecl);
> + if (write_argmap)
> + check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, write_argmap, DIR_WRITE);
I think there are three memory leaks here, anytime the bitmap is non-
null you need a
BITMAP_FREE (foo_argmap);
on it.
Rather than repeating that logic three times, it's probably much
cleaner to combine get_fd_attrs and check_for_fd_attrs into a single
function that:
- builds the bitmap
- bails out early for the common case where there's no attribute
- use the bitmap
- frees it, or, better, uses auto_bitmap rather than bitmap so that
the cleanup happens implicitly
Then the above logic could read:
handle_any_fd_attrs (callee_fndecl, sm_ctxt, node, stmt, call,
"fd_arg", DIR_READ_WRITE);
handle_any_fd_attrs (callee_fndecl, sm_ctxt, node, stmt, call,
"fd_arg_read", DIR_READ);
handle_any_fd_attrs (callee_fndecl, sm_ctxt, node, stmt, call,
"fd_arg_write", DIR_WRITE);
or similar.
> +
> + return true;
> + }
> +
> }
>
> return false;
> }
[...snip...]
> +bitmap
> +fd_state_machine::get_fd_attrs (const char *attr_name, tree callee_fndecl) const
> +{
> + bitmap argmap = NULL;
> + tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (callee_fndecl));
> + attrs = lookup_attribute (attr_name, attrs);
> + if (!attrs)
> + return argmap;
> +
> + if (!TREE_VALUE (attrs))
> + return argmap;
> +
> + argmap = BITMAP_ALLOC (NULL);
> +
> + for (tree idx = TREE_VALUE (attrs); idx; idx = TREE_CHAIN (idx))
> + {
> + unsigned int val = TREE_INT_CST_LOW (TREE_VALUE (idx)) - 1;
We need to be sure that the attribute-validation logic in c-attribs.cc
rejects argument numbers that aren't >= 1. I think the above will
crash if the user supplies an argument number that's 0, negative, or
not an integer. I *think* positional_argument checks for all this and
will reject such attributes, but let's have coverage for each of these
in the test suite.
> + bitmap_set_bit (argmap, val);
> + }
> + return argmap;
> +}
> +
> +
> void
> fd_state_machine::on_open (sm_context *sm_ctxt, const supernode *node,
> const gimple *stmt, const gcall *call) const
> @@ -729,7 +930,7 @@ void
> fd_state_machine::check_for_open_fd (
> sm_context *sm_ctxt, const supernode *node, const gimple *stmt,
> const gcall *call, const tree callee_fndecl,
> - enum access_direction callee_fndecl_dir) const
> + enum fd_access_direction callee_fndecl_dir) const
> {
> tree arg = gimple_call_arg (call, 0);
> tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
> @@ -738,7 +939,7 @@ fd_state_machine::check_for_open_fd (
> if (is_closed_fd_p (state))
> {
> sm_ctxt->warn (node, stmt, arg,
> - new fd_use_after_close (*this, diag_arg, callee_fndecl));
> + new fd_use_after_close (*this, diag_arg, callee_fndecl, false, -1));
I'd prefer overloaded constructors for these fd_diagnostic subclasses,
one for the for the hardcoded case, another for the attribute case, so
that the -1 for the "this is meaningless" attribute argno is only in
the fd_diagnostic constructor.
[...snip...]
> diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
[...snip...]
> +/* Handle the "fd_arg" attribute */
> +
> +static tree
> +handle_fd_arg_attribute (tree *node, tree name, tree args,
> + int ARG_UNUSED (flags), bool *no_add_attrs)
> +{
Am I right in thinking that all three of the handle_fd_arg*_attribute
callback functions are identical? If so, let's just have a single
callback shared by all three entries in the array.
> + tree type = *node;
> + if (!args)
> + {
> + if (!prototype_p (type))
> + {
> + error ("%qE attribute without arguments on a non-prototype", name);
> + *no_add_attrs = true;
> + }
> + return NULL_TREE;
> + }
> +
> + for (int i = 1; args; ++i)
> + {
> + tree pos = TREE_VALUE (args);
> + tree next = TREE_CHAIN (args);
> + if (tree val = positional_argument (type, name, pos, INTEGER_TYPE,
> + next || i > 1 ? i : 0))
> + TREE_VALUE (args) = val;
> + else
> + {
> + *no_add_attrs = true;
> + break;
> + }
> + args = next;
> + }
Looks like you've copied and pasted the above loop from
handle_alloc_size_attribute, which can take multiple args.
The new attributes only take a single argument, so I think
handle_alloc_align_attribute is a better model.
> + return NULL_TREE;
> +}
[...snip...]
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index dfbe33ac652..eba86e9f7ef 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -3007,6 +3007,25 @@ produced by @command{gold}.
> For other linkers that cannot generate resolution file,
> explicit @code{externally_visible} attributes are still necessary.
>
> +@item fd_arg (@Var{N}, @Var{...})
The @var directives should have lower-case "v".
You should add a @cindex line below the @item for each of these; see
the existing function attributes for how to do that.
> +
> +The @Var{fd_arg} attribute may be applied to a function that takes an open file
@Var should be @code here.
> +descriptor at referenced argument @Var{N}. It indicates that the passed file
> +descriptor must not have been closed.
Please spell out which analyzer warnings are affected by this
attribute.
> +
> +@item fd_arg_read (@Var{N}, @Var{...})
Aha: you're supporting 1 or more multiple arguments, rather than just
1?
I don't think we need this, almost every API I can think of takes a
single FD (or is a special-case, like dup2).
So for simplicity, let's just support a single argument per attribute;
if there's a rare case where an API takes two fd_arg_read, the user can
simply supply the attribute twice.
> +
> +The @Var{fd_arg_read} attribute may be applied to function that takes an open file
> +descriptor at referenced argument @Var{N} that it might read from. It
> +indicates that the passed file descriptor must not have been closed or
> +not opened as write-only.
It's probably simplest to document this as: "This attribute is
identical to @code{fd_arg}, but with the additional requirement
that..." or somesuch.
> +
> +@item fd_arg_write (@Var{N}, @Var{...})
> +
> +The @Var{fd_arg_write} attribute may be applied to a function that takes an open
> +file descriptor at referenced argument @Var{N} that it might write to. It indicates
> +that the passed file descriptor must not have been closed or not opened as read-only.
Likewise.
[...snip...]
> diff --git a/gcc/testsuite/gcc.dg/analyzer/fd-6.c b/gcc/testsuite/gcc.dg/analyzer/fd-6.c
> new file mode 100644
> index 00000000000..7efb9e69b58
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/analyzer/fd-6.c
> @@ -0,0 +1,14 @@
> +
> +int not_a_fn __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute only applies to function types" } */
> +
> +void f (char *p) __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute argument value '1' refers to parameter type 'char \\\*'" } */
> +
> +
> +int not_a_fn_b __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute only applies to function types" } */
> +
> +void g (char *p) __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute argument value '1' refers to parameter type 'char \\\*'" } */
> +
> +
> +int not_a_fn_c __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute only applies to function types" } */
> +
> +void f (char *p) __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute argument value '1' refers to parameter type 'char \\\*'" } */
> \ No newline at end of file
The attribute-parsing code isn't analyzer-specific, so move this test
file to c-c++-common/attr-fd.c
Hope the above makes sense; thanks again for the patch
Dave
@@ -39,10 +39,13 @@ along with GCC; see the file COPYING3. If not see
#include "analyzer/analyzer-selftests.h"
#include "tristate.h"
#include "selftest.h"
+#include "stringpool.h"
+#include "attribs.h"
#include "analyzer/call-string.h"
#include "analyzer/program-point.h"
#include "analyzer/store.h"
#include "analyzer/region-model.h"
+#include "bitmap.h"
#if ENABLE_ANALYZER
@@ -59,6 +62,13 @@ enum access_mode
WRITE_ONLY
};
+enum fd_access_direction
+{
+ DIR_READ_WRITE,
+ DIR_READ,
+ DIR_WRITE
+};
+
class fd_state_machine : public state_machine
{
public:
@@ -104,6 +114,8 @@ public:
bool is_readonly_fd_p (state_t s) const;
bool is_writeonly_fd_p (state_t s) const;
enum access_mode get_access_mode_from_flag (int flag) const;
+ void inform_filedescriptor_attribute (tree callee_fndecl, int arg,
+ fd_access_direction fd_dir) const;
/* State for a constant file descriptor (>= 0) */
state_t m_constant_fd;
@@ -146,7 +158,7 @@ private:
void check_for_open_fd (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call,
const tree callee_fndecl,
- enum access_direction access_fn) const;
+ enum fd_access_direction access_fn) const;
void make_valid_transitions_on_condition (sm_context *sm_ctxt,
const supernode *node,
@@ -156,6 +168,12 @@ private:
const supernode *node,
const gimple *stmt,
const svalue *lhs) const;
+ bitmap get_fd_attrs (const char *attr_name, tree callee_fndecl) const;
+ void check_for_fd_attrs (sm_context *sm_ctxt, const supernode *node,
+ const gimple *stmt, const gcall *call,
+ const tree callee_fndecl, bitmap argmap,
+ fd_access_direction fd_attr_access_dir) const;
+
};
/* Base diagnostic class relative to fd_state_machine. */
@@ -294,10 +312,10 @@ class fd_access_mode_mismatch : public fd_diagnostic
{
public:
fd_access_mode_mismatch (const fd_state_machine &sm, tree arg,
- enum access_direction fd_dir,
- const tree callee_fndecl)
+ enum fd_access_direction fd_dir,
+ const tree callee_fndecl, bool attr, int arg_idx)
: fd_diagnostic (sm, arg), m_fd_dir (fd_dir),
- m_callee_fndecl (callee_fndecl)
+ m_callee_fndecl (callee_fndecl), m_attr (attr), m_arg_idx (arg_idx)
{
}
@@ -317,19 +335,27 @@ public:
bool
emit (rich_location *rich_loc) final override
{
+ bool warned;
switch (m_fd_dir)
{
case DIR_READ:
- return warning_at (rich_loc, get_controlling_option (),
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on %<read-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
+ break;
case DIR_WRITE:
- return warning_at (rich_loc, get_controlling_option (),
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on %<write-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
+ break;
default:
gcc_unreachable ();
}
+ if (warned && m_attr)
+ {
+ m_sm.inform_filedescriptor_attribute (m_callee_fndecl, m_arg_idx, m_fd_dir);
+ }
+ return warned;
}
bool
@@ -359,8 +385,10 @@ public:
}
private:
- enum access_direction m_fd_dir;
+ enum fd_access_direction m_fd_dir;
const tree m_callee_fndecl;
+ bool m_attr;
+ int m_arg_idx;
};
class double_close : public fd_diagnostic
@@ -422,8 +450,9 @@ class fd_use_after_close : public fd_diagnostic
{
public:
fd_use_after_close (const fd_state_machine &sm, tree arg,
- const tree callee_fndecl)
- : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl)
+ const tree callee_fndecl, bool attr, int arg_idx)
+ : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl), m_attr (attr),
+ m_arg_idx (arg_idx)
{
}
@@ -439,12 +468,27 @@ public:
return OPT_Wanalyzer_fd_use_after_close;
}
+ bool
+ subclass_equal_p (const pending_diagnostic &base_other) const override
+ {
+ const fd_use_after_close &sub_other
+ = (const fd_use_after_close &)base_other;
+ return (same_tree_p (m_arg, sub_other.m_arg)
+ && m_callee_fndecl == sub_other.m_callee_fndecl
+ && m_attr == sub_other.m_attr
+ && m_arg_idx == sub_other.m_arg_idx);
+ }
+
bool
emit (rich_location *rich_loc) final override
{
- return warning_at (rich_loc, get_controlling_option (),
+ bool warned;
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on closed file descriptor %qE", m_callee_fndecl,
m_arg);
+ if (warned && m_attr)
+ m_sm.inform_filedescriptor_attribute (m_callee_fndecl, m_arg_idx, DIR_READ_WRITE);
+ return warned;
}
label_text
@@ -466,25 +510,29 @@ public:
describe_final_event (const evdesc::final_event &ev) final override
{
if (m_first_close_event.known_p ())
- return ev.formatted_print (
- "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
- m_arg, "close", &m_first_close_event);
- else
- return ev.formatted_print ("%qE on closed file descriptor %qE",
- m_callee_fndecl, m_arg);
+ return ev.formatted_print (
+ "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
+ m_arg, "close", &m_first_close_event);
+ else
+ return ev.formatted_print ("%qE on closed file descriptor %qE",
+ m_callee_fndecl, m_arg);
}
private:
diagnostic_event_id_t m_first_close_event;
const tree m_callee_fndecl;
+ bool m_attr;
+ int m_arg_idx;
};
class unchecked_use_of_fd : public fd_diagnostic
{
public:
unchecked_use_of_fd (const fd_state_machine &sm, tree arg,
- const tree callee_fndecl)
- : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl)
+ const tree callee_fndecl, bool attr,
+ int arg_idx)
+ : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl),
+ m_attr (attr), m_arg_idx (arg_idx)
{
}
@@ -503,9 +551,13 @@ public:
bool
emit (rich_location *rich_loc) final override
{
- return warning_at (rich_loc, get_controlling_option (),
- "%qE on possibly invalid file descriptor %qE",
- m_callee_fndecl, m_arg);
+ bool warned;
+ warned = warning_at (rich_loc, get_controlling_option (),
+ "%qE on possibly invalid file descriptor %qE",
+ m_callee_fndecl, m_arg);
+ if (warned && m_attr)
+ m_sm.inform_filedescriptor_attribute (m_callee_fndecl, m_arg_idx,
+ DIR_READ_WRITE);
}
bool
@@ -514,7 +566,9 @@ public:
const unchecked_use_of_fd &sub_other
= (const unchecked_use_of_fd &)base_other;
return (same_tree_p (m_arg, sub_other.m_arg)
- && m_callee_fndecl == sub_other.m_callee_fndecl);
+ && m_callee_fndecl == sub_other.m_callee_fndecl
+ && m_attr == sub_other.m_attr
+ && m_arg_idx == sub_other.m_arg_idx);
}
label_text
@@ -543,8 +597,40 @@ public:
private:
diagnostic_event_id_t m_first_open_event;
const tree m_callee_fndecl;
+ bool m_attr;
+ int m_arg_idx;
+
};
+/* Issue a note regarding misuse of a file descriptor.
+ ARG_IDX here is 0-based.
+ */
+void
+fd_state_machine::inform_filedescriptor_attribute (
+ tree callee_fndecl, int arg_idx, fd_access_direction fd_dir) const
+{
+ switch (fd_dir)
+ {
+ case READ_WRITE:
+ inform (DECL_SOURCE_LOCATION (callee_fndecl),
+ "argument %d of %qD must be an open file descriptor", arg_idx + 1,
+ callee_fndecl);
+ break;
+ case DIR_WRITE:
+ inform (DECL_SOURCE_LOCATION (callee_fndecl),
+ "argument %d of %qD must be a read-only file descriptor",
+ arg_idx + 1, callee_fndecl);
+ break;
+ case DIR_READ:
+ inform (DECL_SOURCE_LOCATION (callee_fndecl),
+ "argument %d of %qD must be a write-only file descriptor",
+ arg_idx + 1, callee_fndecl);
+ break;
+ }
+}
+
+
+
fd_state_machine::fd_state_machine (logger *logger)
: state_machine ("file-descriptor", logger),
m_constant_fd (add_state ("fd-constant")),
@@ -647,11 +733,126 @@ fd_state_machine::on_stmt (sm_context *sm_ctxt, const supernode *node,
on_read (sm_ctxt, node, stmt, call, callee_fndecl);
return true;
} // "read"
+
+
+ {
+ // Handle __attribute__((fd_arg))
+ bitmap argmap = get_fd_attrs ("fd_arg", callee_fndecl);
+ if (argmap)
+ check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, argmap, DIR_READ_WRITE);
+
+ // Handle __attribute__((fd_arg_read))
+ bitmap read_argmap = get_fd_attrs ("fd_arg_read", callee_fndecl);
+ if(read_argmap)
+ check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, read_argmap, DIR_READ);
+
+ // Handle __attribute__((fd_arg_write))
+ bitmap write_argmap = get_fd_attrs ("fd_arg_write", callee_fndecl);
+ if (write_argmap)
+ check_for_fd_attrs (sm_ctxt, node, stmt, call, callee_fndecl, write_argmap, DIR_WRITE);
+
+ return true;
+ }
+
}
return false;
}
+void
+fd_state_machine::check_for_fd_attrs (sm_context *sm_ctxt,
+ const supernode *node, const gimple *stmt,
+ const gcall *call,
+ const tree callee_fndecl, bitmap argmap,
+ fd_access_direction fd_attr_access_dir) const
+{
+ for (unsigned i = 0; i < gimple_call_num_args (stmt); i++)
+ {
+ unsigned int arg_idx = i;
+ tree arg = gimple_call_arg (stmt, i);
+ tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
+ state_t state = sm_ctxt->get_state (stmt, arg);
+ if (TREE_CODE (TREE_TYPE (arg)) != INTEGER_TYPE)
+ continue;
+ if (bitmap_bit_p (argmap, arg_idx)) // check if the arg is any of the file
+ // descriptor attributes
+ {
+
+ if (is_closed_fd_p (state))
+ {
+
+ sm_ctxt->warn (node, stmt, arg,
+ new fd_use_after_close (*this, diag_arg,
+ callee_fndecl, true,
+ arg_idx));
+ continue;
+ }
+ else
+ {
+ if (!(is_valid_fd_p (state) || (state == m_stop)))
+ {
+ if (!is_constant_fd_p (state))
+ sm_ctxt->warn (node, stmt, arg,
+ new unchecked_use_of_fd (*this, diag_arg,
+ callee_fndecl, true,
+ arg_idx));
+ }
+ }
+ }
+ switch (fd_attr_access_dir)
+ {
+ case DIR_READ:
+ if (bitmap_bit_p (argmap, arg_idx)) // check if the arg is marked by
+ // reads_from_fd attribute
+ {
+ if (is_writeonly_fd_p (state))
+ {
+ sm_ctxt->warn (node, stmt, arg,
+ new fd_access_mode_mismatch (*this, diag_arg,
+ DIR_WRITE,
+ callee_fndecl, true, i));
+ }
+ }
+ break;
+ case DIR_WRITE:
+ if (bitmap_bit_p (argmap, arg_idx)) // check if the arg is marked by
+ // writes_to_fd attribute
+ {
+ if (is_readonly_fd_p (state))
+ {
+ sm_ctxt->warn (node, stmt, arg,
+ new fd_access_mode_mismatch (
+ *this, diag_arg, DIR_READ, callee_fndecl, true, i));
+ }
+ }
+ break;
+ }
+ }
+}
+
+bitmap
+fd_state_machine::get_fd_attrs (const char *attr_name, tree callee_fndecl) const
+{
+ bitmap argmap = NULL;
+ tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (callee_fndecl));
+ attrs = lookup_attribute (attr_name, attrs);
+ if (!attrs)
+ return argmap;
+
+ if (!TREE_VALUE (attrs))
+ return argmap;
+
+ argmap = BITMAP_ALLOC (NULL);
+
+ for (tree idx = TREE_VALUE (attrs); idx; idx = TREE_CHAIN (idx))
+ {
+ unsigned int val = TREE_INT_CST_LOW (TREE_VALUE (idx)) - 1;
+ bitmap_set_bit (argmap, val);
+ }
+ return argmap;
+}
+
+
void
fd_state_machine::on_open (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call) const
@@ -729,7 +930,7 @@ void
fd_state_machine::check_for_open_fd (
sm_context *sm_ctxt, const supernode *node, const gimple *stmt,
const gcall *call, const tree callee_fndecl,
- enum access_direction callee_fndecl_dir) const
+ enum fd_access_direction callee_fndecl_dir) const
{
tree arg = gimple_call_arg (call, 0);
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
@@ -738,7 +939,7 @@ fd_state_machine::check_for_open_fd (
if (is_closed_fd_p (state))
{
sm_ctxt->warn (node, stmt, arg,
- new fd_use_after_close (*this, diag_arg, callee_fndecl));
+ new fd_use_after_close (*this, diag_arg, callee_fndecl, false, -1));
}
else
@@ -748,7 +949,7 @@ fd_state_machine::check_for_open_fd (
if (!is_constant_fd_p (state))
sm_ctxt->warn (
node, stmt, arg,
- new unchecked_use_of_fd (*this, diag_arg, callee_fndecl));
+ new unchecked_use_of_fd (*this, diag_arg, callee_fndecl, false, -1));
}
switch (callee_fndecl_dir)
{
@@ -758,7 +959,7 @@ fd_state_machine::check_for_open_fd (
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
sm_ctxt->warn (node, stmt, arg,
new fd_access_mode_mismatch (
- *this, diag_arg, DIR_WRITE, callee_fndecl));
+ *this, diag_arg, DIR_WRITE, callee_fndecl, false, -1));
}
break;
@@ -769,9 +970,11 @@ fd_state_machine::check_for_open_fd (
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
sm_ctxt->warn (node, stmt, arg,
new fd_access_mode_mismatch (
- *this, diag_arg, DIR_READ, callee_fndecl));
+ *this, diag_arg, DIR_READ, callee_fndecl, false, -1));
}
break;
+ default:
+ gcc_unreachable ();
}
}
}
@@ -173,6 +173,10 @@ static tree handle_objc_nullability_attribute (tree *, tree, tree, int, bool *);
static tree handle_signed_bool_precision_attribute (tree *, tree, tree, int,
bool *);
static tree handle_retain_attribute (tree *, tree, tree, int, bool *);
+static tree handle_fd_arg_attribute (tree *, tree, tree, int, bool *);
+static tree handle_fd_arg_read_attribute (tree *, tree, tree, int, bool *);
+static tree handle_fd_arg_write_attribute (tree *, tree, tree, int, bool *);
+
/* Helper to define attribute exclusions. */
#define ATTR_EXCL(name, function, type, variable) \
@@ -427,6 +431,12 @@ const struct attribute_spec c_common_attribute_table[] =
handle_tls_model_attribute, NULL },
{ "nonnull", 0, -1, false, true, true, false,
handle_nonnull_attribute, NULL },
+ { "fd_arg", 0, -1, false, true, true, false,
+ handle_fd_arg_attribute, NULL},
+ { "fd_arg_read", 0, -1, false, true, true, false,
+ handle_fd_arg_read_attribute, NULL},
+ { "fd_arg_write", 0, -1, false, true, true, false,
+ handle_fd_arg_write_attribute, NULL},
{ "nonstring", 0, 0, true, false, false, false,
handle_nonstring_attribute, NULL },
{ "nothrow", 0, 0, true, false, false, false,
@@ -4521,6 +4531,111 @@ handle_nonnull_attribute (tree *node, tree name,
return NULL_TREE;
}
+/* Handle the "fd_arg" attribute */
+
+static tree
+handle_fd_arg_attribute (tree *node, tree name, tree args,
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ tree type = *node;
+ if (!args)
+ {
+ if (!prototype_p (type))
+ {
+ error ("%qE attribute without arguments on a non-prototype", name);
+ *no_add_attrs = true;
+ }
+ return NULL_TREE;
+ }
+
+ for (int i = 1; args; ++i)
+ {
+ tree pos = TREE_VALUE (args);
+ tree next = TREE_CHAIN (args);
+ if (tree val = positional_argument (type, name, pos, INTEGER_TYPE,
+ next || i > 1 ? i : 0))
+ TREE_VALUE (args) = val;
+ else
+ {
+ *no_add_attrs = true;
+ break;
+ }
+ args = next;
+ }
+ return NULL_TREE;
+}
+
+/* Handle the "fd_arg_read" attribute. */
+
+static tree
+handle_fd_arg_read_attribute (tree *node, tree name, tree ARG_UNUSED (args),
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ tree type = *node;
+ if (!args)
+ {
+ if (!prototype_p (type))
+ {
+ error ("%qE attribute without arguments on a non-prototype", name);
+ *no_add_attrs = true;
+ }
+ return NULL_TREE;
+ }
+
+ for (int i = 1; args; ++i)
+ {
+ tree pos = TREE_VALUE (args);
+ tree next = TREE_CHAIN (args);
+ if (tree val = positional_argument (type, name, pos, INTEGER_TYPE,
+ next || i > 1 ? i : 0))
+ TREE_VALUE (args) = val;
+ else
+ {
+ *no_add_attrs = true;
+ break;
+ }
+ args = next;
+ }
+ return NULL_TREE;
+}
+
+
+/* Handle the "fd_arg_write" attribute. */
+static tree
+handle_fd_arg_write_attribute (tree *node, tree name, tree ARG_UNUSED (args),
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ tree type = *node;
+ if (!args)
+ {
+ if (!prototype_p (type))
+ {
+ error ("%qE attribute without arguments on a non-prototype", name);
+ *no_add_attrs = true;
+ }
+ return NULL_TREE;
+ }
+
+ for (int i = 1; args; ++i)
+ {
+ tree pos = TREE_VALUE (args);
+ tree next = TREE_CHAIN (args);
+ if (tree val = positional_argument (type, name, pos, INTEGER_TYPE,
+ next || i > 1 ? i : 0))
+ TREE_VALUE (args) = val;
+ else
+ {
+ *no_add_attrs = true;
+ break;
+ }
+ args = next;
+ }
+ return NULL_TREE;
+}
+
+
+
+
/* Handle the "nonstring" variable attribute. */
static tree
@@ -3007,6 +3007,25 @@ produced by @command{gold}.
For other linkers that cannot generate resolution file,
explicit @code{externally_visible} attributes are still necessary.
+@item fd_arg (@Var{N}, @Var{...})
+
+The @Var{fd_arg} attribute may be applied to a function that takes an open file
+descriptor at referenced argument @Var{N}. It indicates that the passed file
+descriptor must not have been closed.
+
+@item fd_arg_read (@Var{N}, @Var{...})
+
+The @Var{fd_arg_read} attribute may be applied to function that takes an open file
+descriptor at referenced argument @Var{N} that it might read from. It
+indicates that the passed file descriptor must not have been closed or
+not opened as write-only.
+
+@item fd_arg_write (@Var{N}, @Var{...})
+
+The @Var{fd_arg_write} attribute may be applied to a function that takes an open
+file descriptor at referenced argument @Var{N} that it might write to. It indicates
+that the passed file descriptor must not have been closed or not opened as read-only.
+
@item flatten
@cindex @code{flatten} function attribute
Generally, inlining into a function is limited. For a function marked with
new file mode 100644
@@ -0,0 +1,53 @@
+int open(const char *, int mode);
+void close(int fd);
+int write (int fd, void *buf, int nbytes);
+int read (int fd, void *buf, int nbytes);
+
+#define O_RDONLY 0
+#define O_WRONLY 1
+#define O_RDWR 2
+
+void f (int fd) __attribute__((fd_arg(1))); /* { dg-message "argument 1 of 'f' must be an open file descriptor" } */
+
+void
+test_1 (const char *path)
+{
+ int fd = open (path, O_RDWR);
+ close(fd);
+ f(fd); /* { dg-warning "'f' on closed file descriptor 'fd'" } */
+ /* { dg-message "\\(3\\) 'f' on closed file descriptor 'fd'; 'close' was at \\(2\\)" "" { target *-*-* } .-1 } */
+}
+
+void g (int fd) __attribute__((fd_arg_read(1))); /* { dg-message "argument 1 of 'g' must be a read-only file descriptor" } */
+
+void
+test_2 (const char *path)
+{
+ int fd = open (path, O_WRONLY);
+ if (fd != -1)
+ {
+ g (fd); /* { dg-warning "'g' on 'write-only' file descriptor 'fd'" } */
+ }
+ close (fd);
+}
+
+void h (int fd) __attribute__((fd_arg_write(1))); /* { dg-message "argument 1 of 'h' must be a write-only file descriptor" } */
+void
+test_3 (const char *path)
+{
+ int fd = open (path, O_RDONLY);
+ if (fd != -1)
+ {
+ h (fd); /* { dg-warning "'h' on 'read-only' file descriptor 'fd'" } */
+ }
+ close(fd);
+}
+
+void ff (int fd) __attribute__((fd_arg(1))); /* { dg-message "argument 1 of 'ff' must be an open file descriptor" } */
+
+void test_4 (const char *path)
+{
+ int fd = open (path, O_RDWR);
+ ff (fd); /* { dg-warning "'ff' on possibly invalid file descriptor 'fd'" } */
+ close(fd);
+}
\ No newline at end of file
new file mode 100644
@@ -0,0 +1,14 @@
+
+int not_a_fn __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute only applies to function types" } */
+
+void f (char *p) __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute argument value '1' refers to parameter type 'char \\\*'" } */
+
+
+int not_a_fn_b __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute only applies to function types" } */
+
+void g (char *p) __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute argument value '1' refers to parameter type 'char \\\*'" } */
+
+
+int not_a_fn_c __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute only applies to function types" } */
+
+void f (char *p) __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute argument value '1' refers to parameter type 'char \\\*'" } */
\ No newline at end of file