From patchwork Thu Apr 9 20:04:12 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Wingo X-Patchwork-Id: 6120 Received: (qmail 71506 invoked by alias); 9 Apr 2015 20:04:30 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 71468 invoked by uid 89); 9 Apr 2015 20:04:28 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_LOW, SPF_NEUTRAL autolearn=ham version=3.3.2 X-HELO: sasl.smtp.pobox.com Received: from pb-sasl1.int.icgroup.com (HELO sasl.smtp.pobox.com) (208.72.237.25) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 09 Apr 2015 20:04:19 +0000 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 3E2C8465D6; Thu, 9 Apr 2015 16:04:17 -0400 (EDT) Received: from pb-sasl1.int.icgroup.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 34AE8465D5; Thu, 9 Apr 2015 16:04:17 -0400 (EDT) Received: from rusty (unknown [88.160.190.192]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pb-sasl1.pobox.com (Postfix) with ESMTPSA id 436EE465D4; Thu, 9 Apr 2015 16:04:14 -0400 (EDT) From: Andy Wingo To: gdb-patches@sourceware.org Cc: dje@google.com Subject: [PATCH v5] Add Guile frame unwinder interface Date: Thu, 09 Apr 2015 22:04:12 +0200 Message-ID: <87zj6hdq6b.fsf@igalia.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 X-Pobox-Relay-ID: 990F9DA6-DEF3-11E4-A0D2-99D0625725FD-02397024!pb-sasl1.pobox.com X-IsSubscribed: yes Hi, Changes in this patch: * Remove enable-frame-unwinder!, disable-frame-unwinder! * set-frame-unwinder-enabled! takes frame unwinder object only, not a name * Removed priority; instead, first the unwinders for the current objfile are run, then the ones from the current progspace, then the global ones, but in an unspecified order within each locus * Renamed "scope" to "locus" * Names required to be unique only within locus * s/ephemeral frame/pending frame/ * Documentation updates * make-unwind-info takes a frame-id object; added a make-frame-id constructor. * There's no recursion check in scm-frame-unwinder.c; instead the check in frame_unwind_is_unwinding is sufficient. * I kept the #:enabled init keyword to make-frame-unwinder, as it matches what frame filters do, as well as python filters/unwinders. Let me know if that was an error. * Removed dead "has-active-frame-unwinders?" * Fixed docstring on "all-frame-unwinders" * (prune-frame-unwinders!) doesn't cons if all unwinders are valid (i.e. their loci haven't gone away), and fix prune-frame-unwinders! docstring. * Renamed unregister-frame-unwinder! to remove-frame-unwinder!, as requested. * Fixed test coding style * Fixed some trailing .* in pattern * Test unwind before and after enabling unwinder Still to do: * Make the test architecture-independent if possible There were a couple of questions on the review from v4 of this patch that I address specifically in the thread for v4 and don't mention above. WDYT? :) Andy From 898b8fd80dc5b533be9219472af7645e91d37985 Mon Sep 17 00:00:00 2001 From: Andy Wingo Date: Thu, 5 Mar 2015 16:40:20 +0100 Subject: [PATCH] Add Guile frame unwinder interface gdb/doc/ChangeLog: * guile.texi (Guile Frame Unwinder API): New section. gdb/ChangeLog: * guile/scm-symbol.c (gdbscm_lookup_symbol): Don't error if there is no selected frame and no block is selected; instead, fall back to the current frame. * guile/scm-frame-unwinder.c: New file. * guile/lib/gdb/frame-unwinders.scm: New file. * guile/guile.c (initialize_gdb_module): Call gdbscm_initialize_frame_unwinders. * guile/guile-internal.h (gdbscm_initialize_frame_unwinders): New declaration. * frame.c (get_prev_frame): Detect recursive unwinds, returning NULL in that case. * frame-unwind.h (frame_unwind_got_bytes): Make buf arg const. (frame_unwind_is_unwinding): New declaration. * frame-unwind.c (is_unwinding): New file-local variable. (set_is_unwinding, unset_is_unwinding): New file-local helpers. (frame_unwind_is_unwinding): New exported predicate. (frame_unwind_try_handler): Arrange for frame_unwind_is_unwinding to return true when unwinding the innermost frame. (frame_unwind_got_bytes): Make buf arg const. * data-directory/Makefile.in (GUILE_SOURCE_FILES): Add frame-unwinders.scm. (GUILE_COMPILED_FILES): Add frame-unwinders.go. * Makefile.in (SUBDIR_GUILE_OBS): Add scm-frame-unwinder.o. (SUBDIR_GUILE_SRCS): Add scm-frame-unwinder.c (scm-frame-unwinder.o): New target. gdb/testsuite/ChangeLog: * gdb.guile/scm-frame-unwinder.exp: * gdb.guile/scm-frame-unwinder.c: * gdb.guile/scm-frame-unwinder-gdb.scm.in: * gdb.guile/scm-frame-unwinder.scm: Add unwinder tests. --- gdb/ChangeLog | 29 ++ gdb/Makefile.in | 6 + gdb/data-directory/Makefile.in | 2 + gdb/doc/ChangeLog | 4 + gdb/doc/guile.texi | 210 ++++++++ gdb/frame-unwind.c | 38 +- gdb/frame-unwind.h | 7 +- gdb/frame.c | 16 + gdb/guile/guile-internal.h | 1 + gdb/guile/guile.c | 1 + gdb/guile/lib/gdb/frame-unwinders.scm | 235 +++++++++ gdb/guile/scm-frame-unwinder.c | 570 +++++++++++++++++++++ gdb/guile/scm-symbol.c | 4 +- gdb/testsuite/ChangeLog | 7 + .../gdb.guile/scm-frame-unwinder-gdb.scm.in | 31 ++ gdb/testsuite/gdb.guile/scm-frame-unwinder.c | 35 ++ gdb/testsuite/gdb.guile/scm-frame-unwinder.exp | 90 ++++ gdb/testsuite/gdb.guile/scm-frame-unwinder.scm | 41 ++ 18 files changed, 1324 insertions(+), 3 deletions(-) create mode 100644 gdb/guile/lib/gdb/frame-unwinders.scm create mode 100644 gdb/guile/scm-frame-unwinder.c create mode 100644 gdb/testsuite/gdb.guile/scm-frame-unwinder-gdb.scm.in create mode 100644 gdb/testsuite/gdb.guile/scm-frame-unwinder.c create mode 100644 gdb/testsuite/gdb.guile/scm-frame-unwinder.exp create mode 100644 gdb/testsuite/gdb.guile/scm-frame-unwinder.scm diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 1f15ae6..9af328d 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,34 @@ 2015-04-09 Andy Wingo + * guile/scm-symbol.c (gdbscm_lookup_symbol): Don't error if there + is no selected frame and no block is selected; instead, fall back + to the current frame. + * guile/scm-frame-unwinder.c: New file. + * guile/lib/gdb/frame-unwinders.scm: New file. + * guile/guile.c (initialize_gdb_module): Call + gdbscm_initialize_frame_unwinders. + * guile/guile-internal.h (gdbscm_initialize_frame_unwinders): New + declaration. + * frame.c (get_prev_frame): Detect recursive unwinds, returning + NULL in that case. + * frame-unwind.h (frame_unwind_got_bytes): Make buf arg const. + (frame_unwind_is_unwinding): New declaration. + * frame-unwind.c (is_unwinding): New file-local variable. + (set_is_unwinding, unset_is_unwinding): New file-local helpers. + (frame_unwind_is_unwinding): New exported predicate. + (frame_unwind_try_handler): Arrange for + frame_unwind_is_unwinding to return true when unwinding the + innermost frame. + (frame_unwind_got_bytes): Make buf arg const. + * data-directory/Makefile.in (GUILE_SOURCE_FILES): Add + frame-unwinders.scm. + (GUILE_COMPILED_FILES): Add frame-unwinders.go. + * Makefile.in (SUBDIR_GUILE_OBS): Add scm-frame-unwinder.o. + (SUBDIR_GUILE_SRCS): Add scm-frame-unwinder.c + (scm-frame-unwinder.o): New target. + +2015-04-09 Andy Wingo + * guile/scm-frame-filter.c: * guile/lib/gdb/frame-filters.scm: New files. * guile/guile.c (guile_extension_ops): Add the Guile frame diff --git a/gdb/Makefile.in b/gdb/Makefile.in index 4c664ae..08f432b 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -322,6 +322,7 @@ SUBDIR_GUILE_OBS = \ scm-exception.o \ scm-frame.o \ scm-frame-filter.o \ + scm-frame-unwinder.o \ scm-gsmob.o \ scm-iterator.o \ scm-lazy-string.o \ @@ -349,6 +350,7 @@ SUBDIR_GUILE_SRCS = \ guile/scm-exception.c \ guile/scm-frame.c \ guile/scm-frame-filter.c \ + guile/scm-frame-unwinder.c \ guile/scm-gsmob.c \ guile/scm-iterator.c \ guile/scm-lazy-string.c \ @@ -2440,6 +2442,10 @@ scm-frame-filter.o: $(srcdir)/guile/scm-frame-filter.c $(COMPILE) $(srcdir)/guile/scm-frame-filter.c $(POSTCOMPILE) +scm-frame-unwinder.o: $(srcdir)/guile/scm-frame-unwinder.c + $(COMPILE) $(srcdir)/guile/scm-frame-unwinder.c + $(POSTCOMPILE) + scm-gsmob.o: $(srcdir)/guile/scm-gsmob.c $(COMPILE) $(srcdir)/guile/scm-gsmob.c $(POSTCOMPILE) diff --git a/gdb/data-directory/Makefile.in b/gdb/data-directory/Makefile.in index 21e44b9..b36506c 100644 --- a/gdb/data-directory/Makefile.in +++ b/gdb/data-directory/Makefile.in @@ -90,6 +90,7 @@ GUILE_SOURCE_FILES = \ gdb/boot.scm \ gdb/experimental.scm \ gdb/frame-filters.scm \ + gdb/frame-unwinders.scm \ gdb/init.scm \ gdb/iterator.scm \ gdb/printing.scm \ @@ -102,6 +103,7 @@ GUILE_NO_UNBOUND_WARNING_COMPILED_FILES = \ GUILE_COMPILED_FILES = \ gdb/experimental.go \ gdb/frame-filters.go \ + gdb/frame-unwinders.go \ gdb/iterator.go \ gdb/printing.go \ gdb/support.go \ diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index bcff616..d637482 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,5 +1,9 @@ 2015-04-09 Andy Wingo + * guile.texi (Guile Frame Unwinder API): New section. + +2015-04-09 Andy Wingo + * guile.texi (Guile Frame Filter API) (Writing a Frame Filter in Guile): New sections. diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi index e2826f0..6c850a4 100644 --- a/gdb/doc/guile.texi +++ b/gdb/doc/guile.texi @@ -143,6 +143,7 @@ from the Guile interactive prompt. * Writing a Guile Pretty-Printer:: Writing a pretty-printer * Guile Frame Filter API:: Filtering frames. * Writing a Frame Filter in Guile:: Writing a frame filter. +* Guile Frame Unwinder API:: Programmatically unwinding stack frames * Commands In Guile:: Implementing new commands in Guile * Parameters In Guile:: Adding new @value{GDBN} parameters * Progspaces In Guile:: Program spaces @@ -2119,6 +2120,215 @@ also possible to do the job of an decorator with a filter. Still, avoiding the stream interfaces can often be a good reason to use the simpler decorator layer. +@node Guile Frame Unwinder API +@subsubsection Unwinding Frames in Guile +@cindex frame unwinder api, guile + +In @value{GDBN} terminology, ``unwinding'' is the process of finding +an older (outer) frame on the stack. Unwinders form the core of +backtrace computation in @value{GDBN}. @value{GDBN} comes with +unwinders for each target architecture that it supports, and these +usually suffice to unwind the stack. However, some target programs +can have non-standard frame layouts that cannot be unwound by the +standard unwinders. This is often the case when working with +just-in-time compilation environments, for example in JavaScript +implementations. In such cases, users can define custom code in Guile +to programmatically unwind the problematic stack frames. + +Before getting into the API, we should discuss how unwinders work in +@value{GDBN}. + +As an example, consider a stack in which we have already computed +frame 0 and we want to compute frame 1. We say that frame 0 is the +``inner'' frame, and frame 1 will be the ``outer'' frame. + +Unwinding starts with a model of the state of all registers in an +inner, already unwound frame. In our case, we start with frame 0. +@value{GDBN} then constructs a provisional frame object for the outer +frame that is being built (frame 1) and links it to the inner frame +(frame 0). @value{GDBN} then goes through its list of registered +unwinders, searching for one that knows how to compute the register +state in frame 1, given the state of frame 0. @value{GDBN} will then +ask the chosen unwinder to compute a frame identifier for the outer +frame. Once the unwinder has done so, the frame is marked as +``valid'' and can be accessed using the normal frame API. + +A frame identifier (frame ID) consists of code and data pointers +associated with a frame which will remain valid as long as the frame +is still alive. Usually a frame ID is built from the code and stack +pointers as they were when control entered the function associated +with the frame, though as described below there are other ways to +build a frame ID@. However as you can see, computing the frame ID +requires some input from the unwinder to determine the start code +address (PC) and the frame pointer (FP), especially on platforms that +don't dedicate a register to the FP. + +(Given this description, you might wonder how the frame ID for the +innermost frame (frame 0) is unwound, given that unwinding requires an +inner frame. The answer is that internally, @value{GDBN} always has a +``sentinel'' frame that is inner to the innermost frame, and which has +a pre-computed unwinder that just returns the registers as they are, +without unwinding.) + +The Guile frame unwinder API loosely follows this protocol as +described above. Guile will build a special ``pending frame object'' +corresponding the frame being unwound (in our example, frame 1). It +allows the user to read registers from that pending frame, which in +reality are unwound from the already-existing frame 0. If the +unwinder decides that it can handle the frame in question, it then +creates and returns an ``unwind info'' object for that frame. The +unwind info object contains a frame ID for the pending frame. It also +records the values of any registers saved in the frame, for use when +unwinding its outer frame (frame 2). + +Frame unwinder objects are managed in Guile much in the same way as +frame filters. Indeed, users will often want to implement both frame +unwinders and frame filters: unwinders will compute the correct +backtrace and register state, and filters can fill in function names, +line numbers, and the like. @xref{Guile Frame Filter API}, for more +on frame filters. + +As with frame filters, there can be multiple frame unwinders +registered with @value{GDBN}, and each one may be individually enabled +or disabled at will. The filters will be tried in priority order, +from highest to lowest priority, and the first one that sets the frame +ID will take responsibility for the frame. + +To use frame unwinders, first load the @code{(gdb frame-unwinders)} module +to have access to the procedures that manipulate frame unwinders: + +@example +(use-modules (gdb frame-unwinders)) +@end example + +@deffn {Scheme Procedure} make-frame-unwinder name procedure @ + @r{[}#:priority priority@r{]} @r{[}#:enabled? boolean@r{]} +Make a new frame unwinder. + +The unwinder will be identified by the string @var{name}. +@var{procedure} should be a function of one argument, taking a pending +frame object. If the unwinder procedure decides to handle the frame, +it should return an unwind info object. Otherwise if the unwinder +returns @code{#f}, @value{GDBN} will continue to search its list for +an unwinder. + +The unwinder will be initially enabled, unless the keyword argument +@code{#:enabled? #f} is given. Even if the unwinder is marked as +enabled, it will need to be registered with @value{GDBN} via +@code{register-frame-unwinder!} in order to take effect. +@end deffn + +@deffn {Scheme Procedure} all-frame-unwinders +Return a list of all frame unwinders. +@end deffn + +@deffn {Scheme Procedure} register-frame-unwinder! unwinder @ + @r{[}#:locus locus@r{]} +Register the frame unwinder @var{unwinder} with @value{GDBN}. + +The unwinder will be associated with a specific ``locus'', which may +be an objfile, a progspace, or the ``global'' locus, indicating that +the unwinder should run for all progspaces. The default value of +@code{#f} for @var{locus} indicates that the unwinder should be +registered globally. Pass an objfile or a progspace as the +@code{#:locus} keyword argument to associate the unwinder with a +specific objfile or progspace, respectively. +@end deffn + +Registering an unwinder on an objfile or a progspace locus has the +advantage that the unwinder will go away when the objfile or progspace +is unloaded. To explicitly remove an unwinder from GDB, use +@code{remove-frame-unwinder!}. + +@deffn {Scheme Procedure} remove-frame-unwinder! unwinder +Removes the frame unwinder @var{unwinder} from @value{GDBN}. +@end deffn + +@deffn {Scheme Procedure} set-frame-unwinder-enabled! unwinder enabled? +Mark a frame unwinder as enabled, if @var{enabled?} is true, or as +disabled otherwise. +@end deffn + +Unwinders are enabled when they are created, unless @code{#:enabled? +#f} is passed to @code{make-frame-unwinder}. + +@deffn {Scheme Procedure} frame-unwinder-name unwinder +@deffnx {Scheme Procedure} frame-unwinder-enabled? unwinder +@deffnx {Scheme Procedure} frame-unwinder-registered? unwinder +@deffnx {Scheme Procedure} frame-unwinder-priority unwinder +@deffnx {Scheme Procedure} frame-unwinder-procedure unwinder +@deffnx {Scheme Procedure} frame-unwinder-locus unwinder +Accessors for a frame unwinder object's fields. The +@code{registered?} field indicates whether a unwinder has been added +to @value{GDBN} or not. @code{locus} is the objfile or progspace in +which the unwinder was registered, or @code{#f} otherwise. +@end deffn + +Frame unwinders operate on ``pending frames''. Pending frames are +valid only while they are being unwound; any access to a pending frame +outside the extent of their unwind operation will signal an error. +Currently, pending frames can only be used in two limited ways: to +read registers from the frame, and to construct an unwind info object +for a successful unwinder return. + +@deffn {Scheme Procedure} pending-frame-read-register frame register +Return the value of a register in the pending frame @var{frame}. +@var{register} should be given as a string. +@end deffn + +If an unwinder successfully unwinds a frame, it should return an +unwind info object created via the @code{make-unwind-info} procedure. +An unwind info object specifies the frame ID for its associated +pending frame, and also records values of registers that are saved +within the frame. + +@deffn {Scheme Procedure} make-unwind-info frame frame-id +Make an unwind info object for the pending frame @var{frame}, +specifying @var{frame-id} as its frame ID. @var{frame-id} should be +the result of a call to @code{make-frame-id}. +@end deffn + +@deffn {Scheme Procedure} make-frame-id fp @r{[}#:pc pc@r{]} @r{[}#:special special@r{]} +Build a frame ID object from the given @var{fp}, @var{pc}, and +@var{special} values. + +A frame ID is a unique name for a frame that remains valid as long as +the frame itself is valid. Usually the frame ID is built from from +the frame's stack address and code address. The stack address +@var{fp} should normally be a pointer to the new end of the stack when +the function was called, as a @value{GDBN} value. Similarly the code +address @var{pc} should be given as the address of the entry point of +the function. + +The @var{fp} argument is required. While it is a good idea to specify +a @var{pc}, a code address is not required to build a frame ID, and so +@var{pc} is a keyword argument. Call @code{make-frame-id} with +a @code{#:pc @var{pc}} argument to specify a code address. + +Some architectures have another stack or some other frame state store; +currently this is only the case for ia64. For these odd platforms the +frame ID needs an additional address, which may be passed as the +@var{special} argument, via the @code{#:special} keyword. +@end deffn. + +After building an unwind info object for a pending frame, an unwinder +can call @code{unwind-info-add-saved-register!} to record saved +registers. The values of the saved registers logically belong to the +frame that is older than the pending frame being unwound, not to the +pending frame itself. + +@deffn {Scheme Procedure} unwind-info-add-saved-register! unwind-info register value +Set the saved value of a register in a pending frame. + +@var{register} names a register, and should be a string, for example +@samp{rip}. @var{value} is the register value, as a @value{GDBN} +value. +@end deffn + +Any register whose value is not recorded as saved via +@code{unwind-info-add-saved-register!} will be marked as ``not saved'' +in the outer frame. + @node Commands In Guile @subsubsection Commands In Guile diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c index bba1ae7..4347dca 100644 --- a/gdb/frame-unwind.c +++ b/gdb/frame-unwind.c @@ -87,6 +87,34 @@ frame_unwind_append_unwinder (struct gdbarch *gdbarch, (*ip)->unwinder = unwinder; } +/* Nonzero if we are finding the unwinder for a frame; see + frame_unwind_try_handler. */ +static int is_unwinding = 0; + +/* Return nonzero if we are inside a sniffer call. */ + +int +frame_unwind_is_unwinding (void) +{ + return is_unwinding; +} + +/* Cleanup helpers for is_unwinding. */ + +static void +unset_is_unwinding (void *unused) +{ + is_unwinding = 0; +} + +static struct cleanup* +set_is_unwinding (void) +{ + is_unwinding = 1; + + return make_cleanup (unset_is_unwinding, NULL); +} + /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME unchanged and returns 0. */ @@ -98,11 +126,18 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache, struct cleanup *old_cleanup; int res = 0; + if (is_unwinding) + internal_error (__FILE__, __LINE__, + _("Recursion detected while finding an unwinder.")); old_cleanup = frame_prepare_for_sniffer (this_frame, unwinder); TRY { + struct cleanup *cleanup = set_is_unwinding (); + res = unwinder->sniffer (unwinder, this_frame, this_cache); + + do_cleanups (cleanup); } CATCH (ex, RETURN_MASK_ERROR) { @@ -252,7 +287,8 @@ frame_unwind_got_constant (struct frame_info *frame, int regnum, } struct value * -frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf) +frame_unwind_got_bytes (struct frame_info *frame, int regnum, + const gdb_byte *buf) { struct gdbarch *gdbarch = frame_unwind_arch (frame); struct value *reg_val; diff --git a/gdb/frame-unwind.h b/gdb/frame-unwind.h index 44add12..3e322f2 100644 --- a/gdb/frame-unwind.h +++ b/gdb/frame-unwind.h @@ -179,6 +179,11 @@ extern void frame_unwind_append_unwinder (struct gdbarch *gdbarch, extern void frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache); +/* Return nonzero if we are in the process of finding an unwinder for a frame. + See the comments in get_current_frame. */ + +extern int frame_unwind_is_unwinding (void); + /* Helper functions for value-based register unwinding. These return a (possibly lazy) value of the appropriate type. */ @@ -210,7 +215,7 @@ struct value *frame_unwind_got_constant (struct frame_info *frame, int regnum, inside BUF. */ struct value *frame_unwind_got_bytes (struct frame_info *frame, int regnum, - gdb_byte *buf); + const gdb_byte *buf); /* Return a value which indicates that FRAME's saved version of REGNUM has a known constant (computed) value of ADDR. Convert the diff --git a/gdb/frame.c b/gdb/frame.c index b3cbf23..9e63f21 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -2212,6 +2212,22 @@ get_prev_frame (struct frame_info *this_frame) return NULL; } + /* Unwinders implemented in Python or Scheme could eventually make an API call + that would cause GDB to try to unwind a frame while unwinding a frame. + Because already-unwound frames will be found in the frame cache, unwinding + will only happen at the old end of the stack, which means that any + recursive unwinding attempt will surely lead to unbounded recursion. Ways + this can happen include such common functions as `get_current_arch' or + `lookup_symbol', via `get_selected_frame', so it's impractical to simply + declare these an error. Instead, we detect this case and return NULL, + indicating that the known stack of frames ends here. */ + if (frame_unwind_is_unwinding ()) + { + frame_debug_got_null_frame (this_frame, + "get_prev_frame within unwinder sniffer"); + return NULL; + } + return get_prev_frame_always (this_frame); } diff --git a/gdb/guile/guile-internal.h b/gdb/guile/guile-internal.h index d7c166c..9ca807e 100644 --- a/gdb/guile/guile-internal.h +++ b/gdb/guile/guile-internal.h @@ -598,6 +598,7 @@ extern void gdbscm_initialize_disasm (void); extern void gdbscm_initialize_exceptions (void); extern void gdbscm_initialize_frames (void); extern void gdbscm_initialize_frame_filters (void); +extern void gdbscm_initialize_frame_unwinders (void); extern void gdbscm_initialize_iterators (void); extern void gdbscm_initialize_lazy_strings (void); extern void gdbscm_initialize_math (void); diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c index 176e97e..d1850e7 100644 --- a/gdb/guile/guile.c +++ b/gdb/guile/guile.c @@ -670,6 +670,7 @@ initialize_gdb_module (void *data) gdbscm_initialize_disasm (); gdbscm_initialize_frames (); gdbscm_initialize_frame_filters (); + gdbscm_initialize_frame_unwinders (); gdbscm_initialize_iterators (); gdbscm_initialize_lazy_strings (); gdbscm_initialize_math (); diff --git a/gdb/guile/lib/gdb/frame-unwinders.scm b/gdb/guile/lib/gdb/frame-unwinders.scm new file mode 100644 index 0000000..d668d01 --- /dev/null +++ b/gdb/guile/lib/gdb/frame-unwinders.scm @@ -0,0 +1,235 @@ +;; Frame unwinder support. +;; +;; Copyright (C) 2015 Free Software Foundation, Inc. +;; +;; This file is part of GDB. +;; +;; 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 . + +(define-module (gdb frame-unwinders) + #:use-module ((gdb) #:hide (frame? symbol?)) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-9) + #:use-module (ice-9 match) + #:export (pending-frame-read-register + + make-frame-id + + make-unwind-info + unwind-info-add-saved-register! + + make-frame-unwinder + frame-unwinder? + frame-unwinder-name + frame-unwinder-enabled? + frame-unwinder-registered? + frame-unwinder-procedure + frame-unwinder-locus + + find-frame-unwinder-by-name + + register-frame-unwinder! + remove-frame-unwinder! + set-frame-unwinder-enabled! + + all-frame-unwinders)) + +(define-record-type + (%make-frame-id sp pc special) + frame-id? + (sp frame-id-sp) + (pc frame-id-pc) + (special frame-id-special)) + +(define* (make-frame-id sp #:key pc special) + "Make a new frame identifier, or \"frame ID\". + +A frame ID is a unique name for a frame that remains valid as long as +the frame itself is valid. + +Usually the frame ID is built from from the frame's stack address and +code address. The stack address, SP, should normally be a pointer to +the new end of the stack when the function was called, as a GDB value. + +It is possible to create a frame ID with just an SP, but it's better to +specify a code address (PC) via the #:pc keyword argument. The PC +indicates the address of the entry point of the function. + +Some architectures have another stack or some other frame state store, +like ia64, and they need an additional address, which may be passed as +the #:special keyword argument." + (%make-frame-id sp pc special)) + +;; Silence unbound-toplevel warnings until we can load the extension. +(define %make-unwind-info #f) + +(define (make-unwind-info pending-frame frame-id) + "Make an unwind info object for a given pending frame. FRAME-ID will +the frame ID of the frame." + (%make-unwind-info pending-frame + (frame-id-sp frame-id) + (frame-id-pc frame-id) + (frame-id-special frame-id))) + +(define-record-type + (%make-frame-unwinder name enabled? registered? procedure locus) + frame-unwinder? + ;; string + (name frame-unwinder-name) + ;; bool + (enabled? frame-unwinder-enabled? set-enabled?!) + ;; bool + (registered? frame-unwinder-registered? set-registered?!) + ;; pending-frame -> unwind-info | #f + (procedure frame-unwinder-procedure) + ;; objfile | progspace | #f + (locus frame-unwinder-locus set-locus!)) + +(define* (make-frame-unwinder name procedure #:key (enabled? #t)) + "Make and return a new frame unwinder. NAME and PROCEDURE are +required arguments. Specify #:enabled? to set the enabled status of the +unwinder. + +The unwinder must be registered with GDB via `register-frame-unwinder!' +before it is active." + (let ((registered? #f) (locus #f)) + (%make-frame-unwinder name enabled? registered? procedure locus))) + +;; List of frame unwinders. +(define *frame-unwinders* '()) + +(define (same-scope? a b) + "Return #t if A and B represent the same scope, for the purposes of +frame unwinder selection." + (cond + ;; If either is the global locus, they share a scope. + ((or (not a) (not b)) #t) + ;; If either is an objfile, compare their progspaces, unless the + ;; objfile is invalid. + ((objfile? a) (and (objfile-valid? a) + (same-scope? (objfile-progspace a) b))) + ((objfile? b) (and (objfile-valid? b) + (same-scope? a (objfile-progspace b)))) + ;; Otherwise they are progspaces. If they eq?, it's the same scope. + (else (eq? a b)))) + +(define (is-valid? unwinder) + "Return #t if the locus of UNWINDER is still valid, or otherwise #f if +the objfile or progspace has been removed from GDB." + (let ((locus (frame-unwinder-locus unwinder))) + (cond + ((progspace? locus) (progspace-valid? locus)) + ((objfile? locus) (objfile-valid? locus)) + (else #t)))) + +(define (prune-frame-unwinders!) + "Prune frame unwinders whose objfile or progspace has gone away." + (unless (and-map is-valid? *frame-unwinders*) + (set! *frame-unwinders* + (let lp ((unwinders *frame-unwinders*)) + (match unwinders + (() '()) + ((f . unwinders) + (cond + ((is-valid? f) + (cons f (lp unwinders))) + (else + (set-registered?! f #f) + (lp unwinders))))))))) + +(define (all-frame-unwinders) + "Return a list of all registered frame unwinders." + (prune-frame-unwinders!) + ;; Copy the list to prevent callers from mutating our state. + (list-copy *frame-unwinders*)) + +(define* (register-frame-unwinder! unwinder #:key locus replace?) + "Register a frame unwinder with GDB. Frame unwinders must be +registered before they will be used to unwinder backtraces. + +By default, the unwinder will be registered globally. Specify an +objfile or a progspace as the #:locus keyword argument to instead +register the unwinder as belonging to a specific objfile or progspace. + +The unwinder's name must be unique within its locus. GDB will raise an +exception if the locus already has a unwinder registered with the given +name, unless a true value is passed as the #:replace? keyword argument, +in which case any existing unwinder will be removed from its locus." + (define (check-locus!) + (cond + ((objfile? locus) + (unless (objfile-valid? locus) + (error "Objfile is not valid" locus))) + ((progspace? locus) + (unless (progspace-valid? locus) + (error "Progspace is not valid" locus))) + (locus + (error "Invalid locus" locus)))) + (define (duplicate-unwinder? other) + (and (equal? (frame-unwinder-name other) + (frame-unwinder-name unwinder)) + (eq? (frame-unwinder-locus other) locus))) + + (when (frame-unwinder-registered? unwinder) + (error "Frame unwinder is already registered with GDB" unwinder)) + (check-locus!) + (prune-frame-unwinders!) + (let ((found (find duplicate-unwinder? *frame-unwinders*))) + (when found + (if replace? + (remove-frame-unwinder! found) + (error "Frame unwinder with this name already present in locus" + (frame-unwinder-name filter))))) + (set-registered?! unwinder #t) + (set-locus! unwinder locus) + (set! *frame-unwinders* (cons unwinder *frame-unwinders*))) + +(define (unregister-frame-unwinder! unwinder) + "Unregister a frame unwinder." + (set-registered?! unwinder #f) + (set-locus! unwinder #f) + (set! *frame-unwinders* (delq unwinder *frame-unwinders*))) + +(define* (find-frame-unwinder-by-name name #:optional locus) + (prune-frame-unwinders!) + ;; First check for names within the locus, then within the scope. + (or (find (lambda (unwinder) + (and (equal? name (frame-unwinder-name unwinder)) + (eq? (frame-unwinder-locus unwinder) locus))) + *frame-unwinders*) + (find (lambda (unwinder) + (and (equal? name (frame-unwinder-name unwinder)) + (same-scope? (frame-unwinder-locus unwinder) locus))) + *frame-unwinders*) + (error "no frame unwinder found with name" name))) + +(define (set-frame-unwinder-enabled! unwinder enabled?) + "Enable or disable a frame unwinder." + (set-enabled?! unwinder enabled?) + *unspecified*) + +(define (unwind-frame frame) + (define (try-unwind locus) + (or-map (lambda (unwinder) + (and (frame-unwinder-enabled? unwinder) + (eq? (frame-unwinder-locus unwinder) locus) + ((frame-unwinder-procedure unwinder) frame))) + *frame-unwinders*)) + (prune-frame-unwinders!) + (or (try-unwind (current-objfile)) + (try-unwind (current-progspace)) + ;; Try global unwinders last. + (try-unwind #f))) + +(load-extension "gdb" "gdbscm_load_frame_unwinders") diff --git a/gdb/guile/scm-frame-unwinder.c b/gdb/guile/scm-frame-unwinder.c new file mode 100644 index 0000000..363830c --- /dev/null +++ b/gdb/guile/scm-frame-unwinder.c @@ -0,0 +1,570 @@ +/* Scheme frame unwinding interface. + + Copyright (C) 2015 Free Software Foundation, Inc. + + This file is part of GDB. + + 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 . */ + +/* See README file in this directory for implementation notes, coding + conventions, et.al. */ + +#include "defs.h" +#include "arch-utils.h" +#include "frame-unwind.h" +#include "gdb_obstack.h" +#include "guile-internal.h" +#include "inferior.h" +#include "language.h" +#include "observer.h" +#include "regcache.h" +#include "user-regs.h" +#include "value.h" + +/* Non-zero if the (gdb frame-unwinders) module has been loaded. */ +static int gdbscm_frame_unwinders_loaded = 0; + +/* The captured unwind-frame variable. */ +static SCM unwind_frame = SCM_BOOL_F; + +/* Key that we use when associating data with an architecture. */ +static struct gdbarch_data *uwscm_gdbarch_data; + +/* The frame unwinder interface makes pending frame objects when trying + to unwind frames, and unwind info objects when unwinding is successful. + Here we define the names for the pending frame and unwind info Scheme + data types. */ +static const char pending_frame_smob_name[] = "gdb:pending-frame"; +static const char unwind_info_smob_name[] = "gdb:unwind-info"; + +/* SMOB tag for pending frames and unwind info. */ +static scm_t_bits pending_frame_smob_tag; +static scm_t_bits unwind_info_smob_tag; + +/* Data associated with a pending frame. */ +struct uwscm_pending_frame +{ + /* The frame being unwound, used for the read-register interface. */ + struct frame_info *this_frame; + + /* The architecture of the frame, here for convenience. */ + struct gdbarch *gdbarch; +}; + +/* Data associated with an unwind info object. */ +struct uwscm_unwind_info +{ + /* The associated pending frame. */ + SCM frame; + + /* The frame_id for the associated pending frame. */ + struct frame_id frame_id; + + /* A list of (REGNUM . VALUE) pairs, indicating register values for the + associated pending frame. */ + SCM registers; +}; + +/* Type predicate for pending frames. */ + +static int +uwscm_is_pending_frame (SCM obj) +{ + return SCM_SMOB_PREDICATE (pending_frame_smob_tag, obj); +} + +/* Data accessor for pending frames. */ + +static struct uwscm_pending_frame * +uwscm_pending_frame_data (SCM obj) +{ + gdb_assert (uwscm_is_pending_frame (obj)); + return (struct uwscm_pending_frame *) SCM_SMOB_DATA (obj); +} + +/* Type predicate for unwind info. */ + +static int +uwscm_is_unwind_info (SCM obj) +{ + return SCM_SMOB_PREDICATE (unwind_info_smob_tag, obj); +} + +/* Data accessor for unwind_info. */ + +static struct uwscm_unwind_info * +uwscm_unwind_info_data (SCM obj) +{ + gdb_assert (uwscm_is_unwind_info (obj)); + return (struct uwscm_unwind_info *) SCM_SMOB_DATA (obj); +} + +/* Build a pending frame. */ + +static SCM +uwscm_make_pending_frame (struct frame_info *this_frame) +{ + struct uwscm_pending_frame *data; + + data = scm_gc_malloc (sizeof (*data), pending_frame_smob_name); + + data->this_frame = this_frame; + TRY + { + data->gdbarch = get_frame_arch (this_frame); + } + CATCH (except, RETURN_MASK_ALL) + { + GDBSCM_HANDLE_GDB_EXCEPTION (except); + } + END_CATCH + + SCM_RETURN_NEWSMOB (pending_frame_smob_tag, data); +} + +/* Pending frames may only be accessed from Scheme within the dynamic + extent of the unwind callback. */ + +static int +uwscm_pending_frame_is_valid (SCM pending_frame) +{ + return uwscm_pending_frame_data (pending_frame)->this_frame != NULL; +} + +/* Is this a pending frame that is accessible from Scheme? */ + +static int +uwscm_is_valid_pending_frame (SCM obj) +{ + return uwscm_is_pending_frame (obj) && uwscm_pending_frame_is_valid (obj); +} + +/* Is this an unwind info whose associated pending frame is valid? */ + +static int +uwscm_is_valid_unwind_info (SCM obj) +{ + return uwscm_is_unwind_info (obj) + && uwscm_pending_frame_is_valid (uwscm_unwind_info_data (obj)->frame); +} + +/* Called as the unwind callback finishes to invalidate the pending + frame. */ + +static void +uwscm_invalidate_pending_frame (SCM pending_frame) +{ + gdb_assert (uwscm_pending_frame_is_valid (pending_frame)); + uwscm_pending_frame_data (pending_frame)->this_frame = NULL; +} + +/* Raise a Scheme exception if OBJ is not a valid pending frame. */ + +static void +uwscm_assert_valid_pending_frame (SCM obj, const char *func_name, int pos) +{ + if (!uwscm_is_valid_pending_frame (obj)) + gdbscm_throw (gdbscm_make_type_error (func_name, pos, obj, + "valid ")); +} + +/* Raise a Scheme exception if OBJ is not an unwind info object whose + associated pending frame is valid. */ + +static void +uwscm_assert_valid_unwind_info (SCM obj, const char *func_name, int pos) +{ + if (!uwscm_is_valid_unwind_info (obj)) + gdbscm_throw (gdbscm_make_type_error (func_name, pos, obj, + "valid ")); +} + +/* Helper to convert a frame ID component to a CORE_ADDR. */ + +static CORE_ADDR +uwscm_value_to_addr (SCM value, int arg) +{ + struct value *c_value; + CORE_ADDR ret; + + if (!vlscm_is_value (value)) + gdbscm_throw (gdbscm_make_type_error ("make-unwind-info", + arg, value, " object")); + + c_value = vlscm_scm_to_value (value); + + TRY + { + ret = value_as_address (c_value); + } + CATCH (except, RETURN_MASK_ALL) + { + GDBSCM_HANDLE_GDB_EXCEPTION (except); + } + END_CATCH + + return ret; +} + +/* (%make-unwind-info pending-frame sp pc special) + + Create an unwind info structure for this pending frame. Wrapped in Scheme to + take a frame ID record. */ + +static SCM +gdbscm_make_unwind_info (SCM pending_frame, SCM sp, SCM pc, SCM special) +{ + struct uwscm_unwind_info *data; + struct frame_id frame_id; + + uwscm_assert_valid_pending_frame (pending_frame, FUNC_NAME, SCM_ARG1); + + if (gdbscm_is_false (pc)) + frame_id = frame_id_build_wild (uwscm_value_to_addr (sp, SCM_ARG2)); + else if (gdbscm_is_false (special)) + frame_id = frame_id_build (uwscm_value_to_addr (sp, SCM_ARG2), + uwscm_value_to_addr (pc, SCM_ARG3)); + else + frame_id = frame_id_build_special (uwscm_value_to_addr (sp, SCM_ARG2), + uwscm_value_to_addr (pc, SCM_ARG3), + uwscm_value_to_addr (special, SCM_ARG4)); + + data = scm_gc_malloc (sizeof (*data), unwind_info_smob_name); + + data->frame = pending_frame; + data->frame_id = frame_id; + data->registers = SCM_EOL; + + SCM_RETURN_NEWSMOB (unwind_info_smob_tag, data); +} + +/* Convert the string REGISTER_SCM to a register number for the given + architecture. */ + +static int +uwscm_scm_to_regnum (SCM register_scm, struct gdbarch *gdbarch, + const char *func_name, int arg) +{ + int regnum; + struct cleanup *cleanup; + char *register_str; + + gdbscm_parse_function_args (func_name, arg, NULL, + "s", register_scm, ®ister_str); + cleanup = make_cleanup (xfree, register_str); + + TRY + { + regnum = user_reg_map_name_to_regnum (gdbarch, register_str, + strlen (register_str)); + } + CATCH (except, RETURN_MASK_ALL) + { + do_cleanups (cleanup); + GDBSCM_HANDLE_GDB_EXCEPTION (except); + } + END_CATCH + + do_cleanups (cleanup); + + if (regnum < 0) + gdbscm_out_of_range_error (func_name, arg, + register_scm, _("unknown register")); + + return regnum; +} + +/* (pending-frame-read-register string) + -> + + Sniffs a register value from a pending frame. */ + +static SCM +gdbscm_pending_frame_read_register (SCM pending_frame, SCM register_scm) +{ + struct uwscm_pending_frame *data; + struct value *value = NULL; + int regnum; + + uwscm_assert_valid_pending_frame (pending_frame, FUNC_NAME, SCM_ARG1); + data = uwscm_pending_frame_data (pending_frame); + regnum = uwscm_scm_to_regnum (register_scm, data->gdbarch, FUNC_NAME, + SCM_ARG2); + + TRY + { + value = get_frame_register_value (data->this_frame, regnum); + } + CATCH (except, RETURN_MASK_ALL) + { + GDBSCM_HANDLE_GDB_EXCEPTION (except); + } + END_CATCH + + if (value == NULL) + gdbscm_out_of_range_error (FUNC_NAME, SCM_ARG2, register_scm, + _("cannot read register from frame")); + + return vlscm_scm_from_value (value); +} + +/* (unwind-info-add-saved-register! unwind-info register value) + + Records the saved value of a particular register in UNWIND_INFO's + corresponding pending frame. REGISTER_SCM names the register, as a + string, and VALUE_SCM is a . */ + +static SCM +gdbscm_unwind_info_add_saved_register_x (SCM unwind_info, SCM register_scm, + SCM value_scm) +{ + struct uwscm_unwind_info *data; + struct uwscm_pending_frame *frame_data; + struct value *value; + int regnum; + int value_size; + + uwscm_assert_valid_unwind_info (unwind_info, FUNC_NAME, SCM_ARG1); + data = uwscm_unwind_info_data (unwind_info); + frame_data = uwscm_pending_frame_data (data->frame); + regnum = uwscm_scm_to_regnum (register_scm, frame_data->gdbarch, + FUNC_NAME, SCM_ARG2); + + if (!vlscm_is_value (value_scm)) + gdbscm_throw (gdbscm_make_type_error (FUNC_NAME, SCM_ARG3, + value_scm, + " object")); + + value = vlscm_scm_to_value (value_scm); + value_size = TYPE_LENGTH (value_enclosing_type (value)); + + if (value_size != register_size (frame_data->gdbarch, regnum)) + gdbscm_invalid_object_error ("unwind-info-add-saved-register!", + SCM_ARG3, value_scm, + "wrong sized value for register"); + + data->registers = scm_assv_set_x (data->registers, + scm_from_int (regnum), + value_scm); + + return SCM_UNSPECIFIED; +} + +/* frame_unwind.this_id method. */ + +static void +uwscm_this_id (struct frame_info *this_frame, void **cache_ptr, + struct frame_id *this_id) +{ + SCM unwind_info = PTR2SCM (*cache_ptr); + struct uwscm_unwind_info *data; + + data = uwscm_unwind_info_data (unwind_info); + *this_id = data->frame_id; +} + +/* frame_unwind.prev_register. */ + +static struct value * +uwscm_prev_register (struct frame_info *this_frame, void **cache_ptr, + int regnum) +{ + SCM unwind_info = PTR2SCM (*cache_ptr); + struct uwscm_unwind_info *data; + SCM value_scm; + struct value *c_value; + const gdb_byte *buf; + + data = uwscm_unwind_info_data (unwind_info); + value_scm = scm_assv_ref (data->registers, scm_from_int (regnum)); + if (gdbscm_is_false (value_scm)) + return frame_unwind_got_optimized (this_frame, regnum); + + c_value = vlscm_scm_to_value (value_scm); + buf = value_contents (c_value); + + return frame_unwind_got_bytes (this_frame, regnum, buf); +} + +/* Call unwind-frame on the pending frame and check that the return + value is either a valid unwind info object, for a successful unwind, or + #f otherwise. */ + +static SCM +do_call_unwind_frame (void *data) +{ + SCM pending_frame = PTR2SCM (data); + SCM result; + + result = scm_call_1 (scm_variable_ref (unwind_frame), pending_frame); + + if (!gdbscm_is_false (result)) + uwscm_assert_valid_unwind_info (result, "unwind-frame", 0); + + return result; +} + +/* Sniffer implementation. */ + +static int +uwscm_sniffer (const struct frame_unwind *self, struct frame_info *this_frame, + void **cache_ptr) +{ + SCM pending_frame; + SCM result; + + /* Note that it's possible to have loaded the Guile interface, but not yet + loaded (gdb frame-unwinders), so checking gdb_scheme_initialized is not + sufficient. */ + if (!gdbscm_frame_unwinders_loaded) + return 0; + + pending_frame = uwscm_make_pending_frame (this_frame); + /* Recurse through gdbscm_call_guile so that we can just throw + exceptions on error. */ + result = gdbscm_call_guile (do_call_unwind_frame, + SCM2PTR (pending_frame), + gdbscm_memory_error_p); + + /* Drop the reference to this_frame, so that future use of + pending_frame from Scheme will signal an error. */ + uwscm_invalidate_pending_frame (pending_frame); + + if (gdbscm_is_exception (result)) + { + gdbscm_print_gdb_exception (SCM_BOOL_F, result); + return 0; + } + + if (gdbscm_is_false (result)) + return 0; + + *cache_ptr = SCM2PTR (scm_gc_protect_object (result)); + + return 1; +} + +/* Frame cache release shim. */ + +static void +uwscm_dealloc_cache (struct frame_info *this_frame, void *cache) +{ + scm_gc_unprotect_object (PTR2SCM (cache)); +} + +struct uwscm_gdbarch_data_type +{ + /* Has the unwinder shim been prepended? */ + int unwinder_registered; +}; + +static void * +uwscm_gdbarch_data_init (struct gdbarch *gdbarch) +{ + return GDBARCH_OBSTACK_ZALLOC (gdbarch, struct uwscm_gdbarch_data_type); +} + +/* New inferior architecture callback: register the Guile sniffers + intermediary. */ + +static void +uwscm_on_new_gdbarch (struct gdbarch *newarch) +{ + struct uwscm_gdbarch_data_type *data = + gdbarch_data (newarch, uwscm_gdbarch_data); + + if (!data->unwinder_registered) + { + struct frame_unwind *unwinder + = GDBARCH_OBSTACK_ZALLOC (newarch, struct frame_unwind); + + unwinder->type = NORMAL_FRAME; + unwinder->stop_reason = default_frame_unwind_stop_reason; + unwinder->this_id = uwscm_this_id; + unwinder->prev_register = uwscm_prev_register; + unwinder->unwind_data = (void *) newarch; + unwinder->sniffer = uwscm_sniffer; + unwinder->dealloc_cache = uwscm_dealloc_cache; + frame_unwind_prepend_unwinder (newarch, unwinder); + data->unwinder_registered = 1; + } +} + +static const scheme_function unwind_functions[] = +{ + { "%make-unwind-info", 4, 0, 0, gdbscm_make_unwind_info, + /* Wrapped and documented in Scheme; no need for docs here. */ + ""}, + + { "pending-frame-read-register", 2, 0, 0, + gdbscm_pending_frame_read_register, + "\ +Return the value of a register in a pending frame.\n\ +\n\ + Arguments: string" }, + + { "unwind-info-add-saved-register!", 3, 0, 0, + gdbscm_unwind_info_add_saved_register_x, + "\ +Record the saved value of a register for a pending frame.\n\ +\n\ +After reading a pending frame's registers and determining that it\n\ +can handle the frame, an unwinder will create an unwind info object and\n\ +call this function to record saved registers for the frame. The values\n\ +of the saved registers logically belong to the frame that is older than\n\ +the pending frame being unwound, not to the pending frame itself.\n\ +\n\ +The first argument should be a object. The second\n\ +names a register, and should be a string, for example \"rip\". The\n\ +third argument is the value, as a GDB value. By default, any register\n\ +whose value is not added to the unwind info's saved register set\n\ +will be marked as \"not saved\" in the outer frame." }, + + END_FUNCTIONS +}; + +/* Called by lib/gdb/frame-unwinders.scm. */ + +static void +gdbscm_load_frame_unwinders (void *unused) +{ + if (gdbscm_frame_unwinders_loaded) + return; + + gdbscm_frame_unwinders_loaded = 1; + + gdbscm_define_functions (unwind_functions, 0); + + unwind_frame = scm_c_lookup ("unwind-frame"); +} + +/* Initialize the opaque pending frame and unwind info types and + register gdbscm_load_frame_unwinders for calling by (gdb + frame-unwinders). */ + +void +gdbscm_initialize_frame_unwinders (void) +{ + pending_frame_smob_tag = + gdbscm_make_smob_type (pending_frame_smob_name, 0); + unwind_info_smob_tag = + gdbscm_make_smob_type (unwind_info_smob_name, 0); + + uwscm_gdbarch_data = + gdbarch_data_register_post_init (uwscm_gdbarch_data_init); + observer_attach_architecture_changed (uwscm_on_new_gdbarch); + + scm_c_register_extension ("gdb", "gdbscm_load_frame_unwinders", + gdbscm_load_frame_unwinders, NULL); +} diff --git a/gdb/guile/scm-symbol.c b/gdb/guile/scm-symbol.c index 99ef928..1ad6d0c 100644 --- a/gdb/guile/scm-symbol.c +++ b/gdb/guile/scm-symbol.c @@ -605,7 +605,9 @@ gdbscm_lookup_symbol (SCM name_scm, SCM rest) TRY { - selected_frame = get_selected_frame (_("no frame selected")); + selected_frame = get_selected_frame_if_set (); + if (selected_frame == NULL) + selected_frame = get_current_frame (); block = get_frame_block (selected_frame, NULL); } CATCH (except, RETURN_MASK_ALL) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index e156f57..20e6a70 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,5 +1,12 @@ 2015-04-09 Andy Wingo + * gdb.guile/scm-frame-unwinder.exp: New file. + * gdb.guile/scm-frame-unwinder.c: New file. + * gdb.guile/scm-frame-unwinder-gdb.scm.in: New file. + * gdb.guile/scm-frame-unwinder.scm: New file. + +2015-04-09 Andy Wingo + * gdb.guile/amd64-scm-frame-filter-invalidarg.S: * gdb.guile/scm-frame-filter-gdb.scm.in: * gdb.guile/scm-frame-filter-invalidarg-gdb.scm.in: diff --git a/gdb/testsuite/gdb.guile/scm-frame-unwinder-gdb.scm.in b/gdb/testsuite/gdb.guile/scm-frame-unwinder-gdb.scm.in new file mode 100644 index 0000000..5c658d5 --- /dev/null +++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder-gdb.scm.in @@ -0,0 +1,31 @@ +;; Copyright (C) 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 . + +;; This file is part of the GDB test-suite. It tests Guile-based frame +;; filters. + +(use-modules (gdb) + (gdb frame-unwinders)) + +(define* (install-unwinders! #:optional (locus (current-objfile))) + (define (unwind-frame frame) + #f) + (define (add-unwinder! name) + (register-frame-unwinder! (make-frame-unwinder name unwind-frame) + #:locus locus)) + (add-unwinder! "Auto-loaded dummy") + (add-unwinder! "Auto-loaded dummy 2")) + +(install-unwinders!) diff --git a/gdb/testsuite/gdb.guile/scm-frame-unwinder.c b/gdb/testsuite/gdb.guile/scm-frame-unwinder.c new file mode 100644 index 0000000..6546c67 --- /dev/null +++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder.c @@ -0,0 +1,35 @@ +/* Test file for the Scheme frame unwinding interface. + + Copyright (C) 2015 Free Software Foundation, Inc. + + This file is part of GDB. + + 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 . */ + +int +f2 (int a) +{ + return ++a; +} + +int +f1 (int a, int b) +{ + return f2 (a) + b; +} + +int main (int argc, char *argv[]) +{ + return f1 (1, 2); +} diff --git a/gdb/testsuite/gdb.guile/scm-frame-unwinder.exp b/gdb/testsuite/gdb.guile/scm-frame-unwinder.exp new file mode 100644 index 0000000..6fbe48a --- /dev/null +++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder.exp @@ -0,0 +1,90 @@ +# Copyright (C) 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 . + +# This file is part of the GDB testsuite. It tests Guile-based +# frame-filters. + +load_lib gdb-guile.exp + +standard_testfile + +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } { + return -1 +} + +# Skip all tests if Guile scripting is not enabled. +if { [skip_guile_tests] } { continue } + +# Make the -gdb.scm script available to gdb, it is automagically loaded by gdb. +# Care is taken to put it in the same directory as the binary so that +# gdb will find it. +set remote_obj_guile_file \ + [remote_download \ + host ${srcdir}/${subdir}/${testfile}-gdb.scm.in \ + [standard_output_file ${testfile}-gdb.scm]] + +gdb_reinitialize_dir $srcdir/$subdir +gdb_test_no_output "set auto-load safe-path ${remote_obj_guile_file}" \ + "set auto-load safe-path" +gdb_load ${binfile} +# Verify gdb loaded the script. +gdb_test "info auto-load guile-scripts" "Yes.*/${testfile}-gdb.scm.*" \ + "Test auto-load had loaded guile scripts" + +if ![runto_main] then { + return -1 +} + +# Load global frame-unwinders +set remote_guile_file [gdb_remote_download host \ + ${srcdir}/${subdir}/${testfile}.scm] +gdb_scm_load_file ${remote_guile_file} + +# Test query +gdb_test "guile (map frame-unwinder-name (all-frame-unwinders))" \ + "\\(\"Synthetic\" \"Dummy\" \"Auto-loaded dummy 2\" \"Auto-loaded dummy\"\\)" \ + "all frame unwinders" +gdb_test "guile (map frame-unwinder-enabled? (all-frame-unwinders))" \ + "\\(#f #t #t #t\\)" \ + "all frame unwinders enabled?" + +gdb_test_no_output "guile (set-frame-unwinder-enabled! (find-frame-unwinder-by-name \"Dummy\") #f)" \ + "disable dummy" +gdb_test "guile (frame-unwinder-enabled? (find-frame-unwinder-by-name \"Dummy\"))"\ + "#f" \ + "dummy not enabled" +gdb_test_no_output "guile (set-frame-unwinder-enabled! (find-frame-unwinder-by-name \"Dummy\") #t)" \ + "re-enable dummy" +gdb_test "guile (frame-unwinder-enabled? (find-frame-unwinder-by-name \"Dummy\"))"\ + "#t" \ + "dummy re-enabled" + +gdb_test "bt 10" \ + "\#0 main .*scm-frame-unwinder.c:34" \ + "backtrace from main" + +gdb_test_no_output "guile (set-frame-unwinder-enabled! (find-frame-unwinder-by-name \"Synthetic\") #t)" \ + "enable synthetic unwinder" + +gdb_breakpoint "f2" +gdb_continue_to_breakpoint "breakpoint at f2" + +# It would be nice to the backtrace at this position with and without +# the unwinder, but currently enabling an unwinder doesn't invalidate +# the frame cache. + +gdb_test "bt 10"\ + "\#0 f2 .*scm-frame-unwinder.c:23\r\n\#1 .*\#9 0x0*cabba9e5 in \\?\\? \\(\\)\r\n\\(More stack frames follow...\\)" \ + "backtrace full of cabbages" diff --git a/gdb/testsuite/gdb.guile/scm-frame-unwinder.scm b/gdb/testsuite/gdb.guile/scm-frame-unwinder.scm new file mode 100644 index 0000000..8f91527 --- /dev/null +++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder.scm @@ -0,0 +1,41 @@ +;; Copyright (C) 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 . + +;; This file is part of the GDB test-suite. It tests Guile-based frame +;; filters. + +(use-modules (gdb) + (gdb frame-unwinders)) + +(define (dummy-unwinder frame) + #f) + +(register-frame-unwinder! (make-frame-unwinder "Dummy" dummy-unwinder)) + + +(define (synthetic-unwinder frame) + ;; Increment the stack pointer, set IP to 0xdeadbeef + (let* ((this-pc (pending-frame-read-register frame "rip")) + (this-sp (pending-frame-read-register frame "rsp")) + (prev-pc (value-cast (make-value #xcabba9e5) (value-type this-pc))) + (prev-sp (value-add this-sp 32)) + (frame-id (make-frame-id this-sp #:pc this-pc)) + (unwind-info (make-unwind-info frame frame-id))) + (unwind-info-add-saved-register! unwind-info "rip" prev-pc) + (unwind-info-add-saved-register! unwind-info "rsp" prev-sp) + unwind-info)) + +(register-frame-unwinder! + (make-frame-unwinder "Synthetic" synthetic-unwinder #:enabled? #f))