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[PATCH v2] Add Guile frame unwinder interface
- From: Andy Wingo <wingo at igalia dot com>
- To: gdb-patches at sourceware dot org
- Cc: asmundak at google dot com
- Date: Mon, 09 Mar 2015 11:34:33 +0100
- Subject: [PATCH v2] Add Guile frame unwinder interface
- Authentication-results: sourceware.org; auth=none
- References: <87oao7wi66 dot fsf at igalia dot com>
Hi,
New patch adds documentation and tests and cleans up the
frame_unwind_is_unwinding() hack. At this point I am actually OK with
the hack; it's simple enough and has a sensible meaning.
WDYT?
Andy
>From 6cefad33932909549cfbba7e9c1364a2f8279854 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@igalia.com>
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.
(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 | 32 ++
gdb/Makefile.in | 6 +
gdb/data-directory/Makefile.in | 2 +
gdb/doc/ChangeLog | 4 +
gdb/doc/guile.texi | 188 +++++++
gdb/frame-unwind.c | 20 +-
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 | 213 ++++++++
gdb/guile/scm-frame-unwinder.c | 566 +++++++++++++++++++++
gdb/guile/scm-symbol.c | 4 +-
gdb/testsuite/ChangeLog | 7 +
.../gdb.guile/scm-frame-unwinder-gdb.scm.in | 32 ++
gdb/testsuite/gdb.guile/scm-frame-unwinder.c | 30 ++
gdb/testsuite/gdb.guile/scm-frame-unwinder.exp | 84 +++
gdb/testsuite/gdb.guile/scm-frame-unwinder.scm | 41 ++
18 files changed, 1251 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 d55daf6..f9ea8e2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,35 @@
+2015-03-05 Andy Wingo <wingo@igalia.com>
+
+ * 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 an attempt to recursively
+ unwind from the sentinel, and return NULL.
+ * frame-unwind.h (frame_unwind_got_bytes): Make buf arg const.
+ (frame_unwind_is_unwinding_innermost_frame): New declaration.
+ * frame-unwind.c (unwinding_innermost_frame): New file-local
+ variable.
+ (innermost_frame_unwind_begin, innermost_frame_unwind_end): New
+ functions.
+ (frame_unwind_is_unwinding_innermost_frame): New exported
+ predicate.
+ (frame_unwind_find_by_frame): Arrange for
+ frame_unwind_is_unwinding_innermost_frame 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.
+
2015-02-20 Andy Wingo <wingo@igalia.com>
* guile/scm-value.c (gdbscm_value_dynamic_type): Fix typo in which
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 0ab4c51..c9110f0 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -315,6 +315,7 @@ 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 \
@@ -342,6 +343,7 @@ 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 \
@@ -2418,6 +2420,10 @@ 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 75aab1b..bb2722d 100644
--- a/gdb/data-directory/Makefile.in
+++ b/gdb/data-directory/Makefile.in
@@ -91,6 +91,7 @@ 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 \
@@ -101,6 +102,7 @@ GUILE_COMPILED_FILES = \
./gdb.go \
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 a8cfbd9..8f9faae 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2015-03-06 Andy Wingo <wingo@igalia.com>
+
+ * guile.texi (Guile Frame Unwinder API): New section.
+
2015-02-20 Andy Wingo <wingo@igalia.com>
* guile.texi (Frames In Guile): Describe frame-read-register.
diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi
index 05a7806..cc9a332 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
@@ -2125,6 +2126,193 @@ 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}, computing the register state in
+each frame. @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 ephemeral 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 unwind the frame. When
+it finds one, @value{GDBN} will ask the 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 a pair of 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 ``ephemeral frame
+object'' corresponding the frame being unwound (in our example,
+frame 1). It allows the user to read registers from that ephemeral
+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 sets the frame ID on the ephemeral 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{]} @
+ @r{[}#:objfile objfile@r{]} @r{[}#:progspace progspace@r{]}
+
+Make a new frame unwinder. @var{procedure} should be a function of one
+argument, taking an ephemeral frame object. If the unwinder procedure
+decides to handle the frame, it should call
+@code{set-ephemeral-frame-id!} to set the frame ID@. Otherwise,
+@value{GDBN} will continue to search its list for an unwinder.
+
+By default, the scope of the unwinder is global, meaning that it is
+associated with all objfiles and progspaces. Pass one of
+@code{#:objfile} or @code{#:progspace} to instead scope the unwinder
+into a specific objfile or progspace, respectively.
+
+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 added to @value{GDBN}'s set of active
+unwinders via @code{add-frame-unwinder!} in order to take effect.
+When added, the unwinder will be inserted into the list of registered
+unwinders with the given @var{priority}, which should be a number, and
+which defaults to 20 if not given. Higher priority unwinders will be
+tried before lower-priority unwinders.
+@end deffn
+
+@deffn {Scheme Procedure} all-frame-unwinders
+Return a list of all frame unwinders.
+@end deffn
+
+@deffn {Scheme Procedure} add-frame-unwinder! unwinder
+@deffnx {Scheme Procedure} remove-frame-unwinder! unwinder
+Register or unregister the frame unwinder @var{unwinder} with
+@value{GDBN}. Frame unwinders are also implicitly unregistered when
+their objfile or progspace goes away.
+@end deffn
+
+@deffn {Scheme Procedure} enable-frame-unwinder! unwinder
+@deffnx {Scheme Procedure} disable-frame-unwinder! unwinder
+Enable or disable a frame unwinder, respectively. @var{unwinder} can
+either be a frame unwinder object, or it can be a string naming a
+unwinder in the current scope. If no such unwinder is found, an error
+is signalled.
+@end deffn
+
+@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-scope 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{scope} is the objfile or progspace in
+which the unwinder was registered, or @code{#f} otherwise.
+@end deffn
+
+Frame unwinders operate on ``ephemeral frames''. Ephemeral frames are
+valid only while they are being unwound; any access to an ephemeral
+frame outside the extent of their unwind operation will signal an
+error. Only three operations are supported on ephemeral frames:
+reading their registers, setting their frame ID, and adding saved
+register values.
+
+@deffn {Scheme Procedure} ephemeral-frame-read-register frame register
+Return the value of a register in the ephemeral frame @var{frame}.
+@var{register} should be given as a string.
+@end deffn
+
+@deffn {Scheme Procedure} set-ephemeral-frame-id! frame fp [pc [special]]
+Set the frame ID on ephemeral frame @var{frame}, thereby taking
+responsibility for unwinding the frame.
+
+@var{fp}, @var{pc}, and @var{special} are used to build the 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
+@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.
+
+For most architectures, it is sufficient to just specify just the
+stack and code pointers @var{fp} and @var{pc}. Some architectures
+have another stack or some other frame state store, like ia64. For
+these platforms the frame ID needs an additional address, which may be
+passed as the @var{special} optional argument.
+
+It is possible to create a frame ID with just a stack address, but
+it's better to specify a code address as well if possible.
+@end deffn
+
+@deffn {Scheme Procedure} ephemeral-frame-add-saved-register! frame register value
+Set the saved value of a register in a ephemeral frame.
+
+After reading an ephemeral frame's registers and determining that it
+can handle the frame, an unwinder will call this function to record
+saved registers. The values of the saved registers logically belong
+to the frame that is older than the ephemeral frame being unwound, not
+the ephemeral frame itself.
+
+@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. Alternately, passing @code{#f} as the value will mark the
+register as unavailable.
+@end deffn
+
@node Commands In Guile
@subsubsection Commands In Guile
diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index e73650a..6507ee1 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -87,6 +87,18 @@ 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;
+}
+
/* 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. */
@@ -99,12 +111,17 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
volatile struct gdb_exception ex;
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);
+ is_unwinding = 1;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
res = unwinder->sniffer (unwinder, this_frame, this_cache);
}
+ is_unwinding = 0;
if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
{
/* This usually means that not even the PC is available,
@@ -249,7 +266,8 @@ 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..f706e54 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 6b1be94..81431bb 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -2209,6 +2209,22 @@ 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 4ed8cbb..5231f93 100644
--- a/gdb/guile/guile-internal.h
+++ b/gdb/guile/guile-internal.h
@@ -610,6 +610,7 @@ 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 bbc4340..4726d5f 100644
--- a/gdb/guile/guile.c
+++ b/gdb/guile/guile.c
@@ -664,6 +664,7 @@ 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..494a571
--- /dev/null
+++ b/gdb/guile/lib/gdb/frame-unwinders.scm
@@ -0,0 +1,213 @@
+;; 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 <http://www.gnu.org/licenses/>.
+
+(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 (set-ephemeral-frame-id!
+ ephemeral-frame-read-register
+ ephemeral-frame-add-saved-register!
+
+ make-frame-unwinder
+ frame-unwinder?
+ frame-unwinder-name
+ frame-unwinder-enabled?
+ frame-unwinder-registered?
+ frame-unwinder-priority
+ frame-unwinder-procedure
+ frame-unwinder-scope
+
+ find-frame-unwinder-by-name
+
+ add-frame-unwinder!
+ remove-frame-unwinder!
+ enable-frame-unwinder!
+ disable-frame-unwinder!
+
+ all-frame-unwinders))
+
+(define-record-type <frame-unwinder>
+ (%make-frame-unwinder name priority enabled? registered? procedure scope)
+ frame-unwinder?
+ ;; string
+ (name frame-unwinder-name)
+ ;; real
+ (priority frame-unwinder-priority set-priority!)
+ ;; bool
+ (enabled? frame-unwinder-enabled? set-enabled?!)
+ ;; bool
+ (registered? frame-unwinder-registered? set-registered?!)
+ ;; ephemeral-frame -> *
+ (procedure frame-unwinder-procedure)
+ ;; objfile | progspace | #f
+ (scope frame-unwinder-scope))
+
+(define* (make-frame-unwinder name procedure #:key
+ objfile progspace (priority 20) (enabled? #t))
+ "Make and return a new frame unwinder. NAME and PROCEDURE are
+required arguments. Specify #:objfile or #:progspace to limit the frame
+unwinder to a given scope, and #:priority or #:enabled? to set the
+priority and enabled status of the unwinder.
+
+The unwinder must be added to the active set via `add-frame-unwinder!'
+before it is active."
+ (define (compute-scope objfile progspace)
+ (cond
+ (objfile
+ (when progspace
+ (error "Only one of #:objfile or #:progspace may be given"))
+ (unless (objfile? objfile)
+ (error "Not an objfile" objfile))
+ objfile)
+ (progspace
+ (unless (progspace? progspace)
+ (error "Not a progspace" progspace))
+ progspace)
+ (else #f)))
+ (let ((registered? #f)
+ (scope (compute-scope objfile progspace)))
+ (%make-frame-unwinder name priority enabled? registered? procedure scope)))
+
+;; List of frame unwinders, sorted by priority from highest to lowest.
+(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 scope, they share a scope.
+ ((or (not a) (not b)) #t)
+ ;; If either is an objfile, compare their progspaces.
+ ((objfile? a) (same-scope? (objfile-progspace a) b))
+ ((objfile? 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 scope of UNWINDER is still valid, or otherwise #f if
+the objfile or progspace has been removed from GDB."
+ (let ((scope (frame-unwinder-scope unwinder)))
+ (cond
+ ((progspace? scope) (progspace-valid? scope))
+ ((objfile? scope) (objfile-valid? scope))
+ (else #t))))
+
+(define (all-frame-unwinders)
+ "Return a list of all active frame unwinders, ordered from highest to
+lowest priority."
+ ;; Copy the list to prevent callers from mutating our state.
+ (list-copy *frame-unwinders*))
+
+(define* (has-active-frame-unwinders? #:optional
+ (scope (current-progspace)))
+ "Return #t if there are active frame unwinders for the given scope, or
+#f otherwise."
+ (let lp ((unwinders *frame-unwinders*))
+ (match unwinders
+ (() #f)
+ ((unwinder . unwinders)
+ (or (and (frame-unwinder-enabled? unwinder)
+ (same-scope? (frame-unwinder-scope unwinder) scope))
+ (lp unwinders))))))
+
+(define (prune-frame-unwinders!)
+ "Prune frame unwinders whose objfile or progspace has gone away,
+returning a fresh list of 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 (add-frame-unwinder! unwinder)
+ "Add a frame unwinder to the active set. Frame unwinders must be
+added before they will be used to unwinder backtraces."
+ (define (duplicate-unwinder? other)
+ (and (equal? (frame-unwinder-name other)
+ (frame-unwinder-name unwinder))
+ (same-scope? (frame-unwinder-scope other)
+ (frame-unwinder-scope unwinder))))
+ (define (priority>=? a b)
+ (>= (frame-unwinder-priority a) (frame-unwinder-priority b)))
+ (define (insert-sorted elt xs <=?)
+ (let lp ((xs xs))
+ (match xs
+ (() (list elt))
+ ((x . xs*)
+ (if (<=? elt x)
+ (cons elt xs)
+ (cons x (lp xs*)))))))
+
+ (prune-frame-unwinders!)
+ (when (or-map duplicate-unwinder? *frame-unwinders*)
+ (error "Frame unwinder with this name already present in scope"
+ (frame-unwinder-name unwinder)))
+ (set-registered?! unwinder #t)
+ (set! *frame-unwinders*
+ (insert-sorted unwinder *frame-unwinders* priority>=?)))
+
+(define (remove-frame-unwinder! unwinder)
+ "Remove a frame unwinder from the active set."
+ (set-registered?! unwinder #f)
+ (set! *frame-unwinders* (delq unwinder *frame-unwinders*)))
+
+(define* (find-frame-unwinder-by-name name #:optional
+ (scope (current-progspace)))
+ (prune-frame-unwinders!)
+ (or (find (lambda (unwinder)
+ (and (equal? name (frame-unwinder-name unwinder))
+ (same-scope? (frame-unwinder-scope unwinder) scope)))
+ *frame-unwinders*)
+ (error "no frame unwinder found with name" name)))
+
+(define (enable-frame-unwinder! unwinder)
+ "Mark a frame unwinder as enabled."
+ (let ((unwinder (if (frame-unwinder? unwinder)
+ unwinder
+ (find-frame-unwinder-by-name unwinder))))
+ (set-enabled?! unwinder #t)
+ *unspecified*))
+
+(define (disable-frame-unwinder! unwinder)
+ "Mark a frame unwinder as disabled."
+ (let ((unwinder (if (frame-unwinder? unwinder)
+ unwinder
+ (find-frame-unwinder-by-name unwinder))))
+ (set-enabled?! unwinder #f)
+ *unspecified*))
+
+(define (unwind-frame frame)
+ (let ((scope (current-progspace)))
+ (or-map (lambda (unwinder)
+ (and (frame-unwinder-enabled? unwinder)
+ (same-scope? (frame-unwinder-scope unwinder) scope)
+ (begin
+ ((frame-unwinder-procedure unwinder) frame)
+ (ephemeral-frame-has-id? frame))))
+ *frame-unwinders*)))
+
+(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..009b13d
--- /dev/null
+++ b/gdb/guile/scm-frame-unwinder.c
@@ -0,0 +1,566 @@
+/* Scheme interface to the JIT reader.
+
+ 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 <http://www.gnu.org/licenses/>. */
+
+/* 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 apply-frame-filter 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 computes ephemeral frame objects when it
+ is able to unwind a frame. Here we define the name for the ephemeral
+ frame Scheme data type. */
+static const char ephemeral_frame_smob_name[] = "gdb:ephemeral-frame";
+
+/* SMOB tag for ephemeral frames. */
+static scm_t_bits ephemeral_frame_smob_tag;
+
+/* Data associated with a ephemeral frame. */
+struct uwscm_ephemeral_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;
+
+ /* The frame_id for the ephemeral frame; initially unset. */
+ struct frame_id frame_id;
+
+ /* Nonzero if the frame_id has been set. */
+ int has_frame_id;
+
+ /* A list of (REGNUM . VALUE) pairs, indicating register values for the
+ ephemeral frame. */
+ SCM registers;
+};
+
+/* Type predicate for ephemeral frames. */
+
+static int
+uwscm_is_ephemeral_frame (SCM obj)
+{
+ return SCM_SMOB_PREDICATE (ephemeral_frame_smob_tag, obj);
+}
+
+/* Data accessor for ephemeral frames. */
+
+static struct uwscm_ephemeral_frame *
+uwscm_ephemeral_frame_data (SCM obj)
+{
+ gdb_assert (uwscm_is_ephemeral_frame (obj));
+ return (struct uwscm_ephemeral_frame *) SCM_SMOB_DATA (obj);
+}
+
+/* Build a ephemeral frame. */
+
+static SCM
+uwscm_make_ephemeral_frame (struct frame_info *this_frame)
+{
+ struct uwscm_ephemeral_frame *data;
+ volatile struct gdb_exception except;
+
+ data = scm_gc_malloc (sizeof (*data), ephemeral_frame_smob_name);
+
+ data->this_frame = this_frame;
+ TRY_CATCH (except, RETURN_MASK_ALL)
+ {
+ data->gdbarch = get_frame_arch (this_frame);
+ }
+ GDBSCM_HANDLE_GDB_EXCEPTION (except);
+ data->has_frame_id = 0;
+ data->registers = SCM_EOL;
+
+ SCM_RETURN_NEWSMOB (ephemeral_frame_smob_tag, data);
+}
+
+/* Ephemeral frames may only be accessed from Scheme within the dynamic
+ extent of the unwind callback. */
+
+static int
+uwscm_ephemeral_frame_is_valid (SCM ephemeral_frame)
+{
+ return uwscm_ephemeral_frame_data (ephemeral_frame)->this_frame != NULL;
+}
+
+/* Is this an ephemeral frame that is accessible from Scheme? */
+
+static int
+uwscm_is_valid_ephemeral_frame (SCM obj)
+{
+ return uwscm_is_ephemeral_frame (obj) && uwscm_ephemeral_frame_is_valid (obj);
+}
+
+/* Called as the unwind callback finishes to invalidate the ephemeral
+ frame. */
+
+static void
+uwscm_invalidate_ephemeral_frame (SCM ephemeral_frame)
+{
+ gdb_assert(uwscm_ephemeral_frame_is_valid (ephemeral_frame));
+ uwscm_ephemeral_frame_data (ephemeral_frame)->this_frame = NULL;
+}
+
+/* Raise a Scheme exception if OBJ is not a valid ephemeral frame. */
+
+static void
+uwscm_assert_valid_ephemeral_frame (SCM obj, const char *func_name, int pos)
+{
+ if (!uwscm_is_valid_ephemeral_frame (obj))
+ gdbscm_throw (gdbscm_make_type_error (func_name, pos, obj,
+ "valid <gdb:ephemeral-frame>"));
+}
+
+/* (ephemeral-frame-has-id? ephemeral-frame) -> bool
+
+ Has this ephemeral frame been given a frame ID? */
+
+static SCM
+uwscm_ephemeral_frame_has_id_p (SCM ephemeral_frame)
+{
+ struct uwscm_ephemeral_frame *data;
+
+ uwscm_assert_valid_ephemeral_frame (ephemeral_frame, FUNC_NAME, SCM_ARG1);
+
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ return scm_from_bool (data->has_frame_id);
+}
+
+/* Helper to convert a frame ID component to a CORE_ADDR. */
+
+static CORE_ADDR
+uwscm_value_to_addr (SCM value, int arg)
+{
+ volatile struct gdb_exception except;
+ struct value *c_value;
+ CORE_ADDR ret;
+
+ if (!vlscm_is_value (value))
+ gdbscm_throw (gdbscm_make_type_error ("set-ephemeral-frame-id!",
+ arg, value, "<gdb:value> object"));
+
+ c_value = vlscm_scm_to_value (value);
+
+ TRY_CATCH (except, RETURN_MASK_ALL)
+ {
+ ret = value_as_address (c_value);
+ }
+ GDBSCM_HANDLE_GDB_EXCEPTION (except);
+
+ return ret;
+}
+
+/* (set-ephemeral-frame-id! ephemeral-frame stack-address
+ [code-address [special-address]])
+
+ Set the frame ID on this ephemeral frame. */
+
+static SCM
+uwscm_set_ephemeral_frame_id_x (SCM ephemeral_frame, SCM sp, SCM ip,
+ SCM special)
+{
+ struct uwscm_ephemeral_frame *data;
+ struct frame_id frame_id;
+
+ uwscm_assert_valid_ephemeral_frame (ephemeral_frame, FUNC_NAME, SCM_ARG1);
+
+ if (SCM_UNBNDP (ip))
+ frame_id = frame_id_build_wild (uwscm_value_to_addr (sp, SCM_ARG2));
+ if (SCM_UNBNDP (special))
+ frame_id = frame_id_build (uwscm_value_to_addr (sp, SCM_ARG2),
+ uwscm_value_to_addr (ip, SCM_ARG3));
+ else
+ frame_id = frame_id_build_special (uwscm_value_to_addr (sp, SCM_ARG2),
+ uwscm_value_to_addr (ip, SCM_ARG3),
+ uwscm_value_to_addr (special, SCM_ARG4));
+
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ data->frame_id = frame_id;
+ data->has_frame_id = 1;
+
+ return SCM_UNSPECIFIED;
+}
+
+/* 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)
+{
+ int regnum;
+
+ volatile struct gdb_exception except;
+ struct cleanup *cleanup;
+ char *register_str;
+
+ gdbscm_parse_function_args ("ephemeral-frame-add-saved-register!", SCM_ARG2,
+ NULL, "s", register_scm, ®ister_str);
+ cleanup = make_cleanup (xfree, register_str);
+
+ TRY_CATCH (except, RETURN_MASK_ALL)
+ {
+ regnum = user_reg_map_name_to_regnum (gdbarch, register_str,
+ strlen (register_str));
+ }
+ do_cleanups (cleanup);
+ GDBSCM_HANDLE_GDB_EXCEPTION (except);
+
+ if (regnum < 0)
+ gdbscm_out_of_range_error ("ephemeral-frame-add-saved-register!", SCM_ARG2,
+ register_scm, _("unknown register"));
+
+ return regnum;
+}
+
+/* (ephemeral-frame-read-register <gdb:ephemeral-frame> string)
+ -> <gdb:value>
+
+ Sniffs a register value from an ephemeral frame. */
+
+static SCM
+uwscm_ephemeral_frame_read_register (SCM ephemeral_frame, SCM register_scm)
+{
+ volatile struct gdb_exception except;
+ struct uwscm_ephemeral_frame *data;
+ struct value *value = NULL;
+ int regnum;
+
+ uwscm_assert_valid_ephemeral_frame (ephemeral_frame, FUNC_NAME, SCM_ARG1);
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ regnum = uwscm_scm_to_regnum (register_scm, data->gdbarch);
+
+ TRY_CATCH (except, RETURN_MASK_ALL)
+ {
+ gdb_byte buffer[MAX_REGISTER_SIZE];
+
+ value = get_frame_register_value (data->this_frame, regnum);
+ }
+ GDBSCM_HANDLE_GDB_EXCEPTION (except);
+
+ 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);
+}
+
+/* (ephemeral-frame-add-saved-register! ephemeral-frame register value)
+
+ Records the saved value of a particular register in EPHEMERAL_FRAME.
+ REGISTER_SCM names the register, as a string, and VALUE_SCM is a
+ <gdb:value>, or #f to indicate that the register was not saved by the
+ ephemeral frame. */
+
+static SCM
+uwscm_ephemeral_frame_add_saved_register_x (SCM ephemeral_frame,
+ SCM register_scm,
+ SCM value_scm)
+{
+ struct uwscm_ephemeral_frame *data;
+ struct value *value;
+ int regnum;
+ int value_size;
+
+ uwscm_assert_valid_ephemeral_frame (ephemeral_frame, FUNC_NAME, SCM_ARG1);
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ regnum = uwscm_scm_to_regnum (register_scm, data->gdbarch);
+
+ if (!gdbscm_is_false (value_scm))
+ {
+ if (!vlscm_is_value (value_scm))
+ gdbscm_throw (gdbscm_make_type_error (FUNC_NAME, SCM_ARG3,
+ value_scm,
+ "<gdb:value> object"));
+
+ value = vlscm_scm_to_value (value_scm);
+ value_size = TYPE_LENGTH (value_enclosing_type (value));
+
+ if (value_size != register_size (data->gdbarch, regnum))
+ gdbscm_invalid_object_error ("ephemeral-frame-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 ephemeral_frame = PTR2SCM (*cache_ptr);
+ struct uwscm_ephemeral_frame *data;
+
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ *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 ephemeral_frame = PTR2SCM (*cache_ptr);
+ struct uwscm_ephemeral_frame *data;
+ SCM value_scm;
+ struct value *c_value;
+ const gdb_byte *buf;
+
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ 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);
+}
+
+/* Sniffer implementation. */
+
+static int
+uwscm_sniffer (const struct frame_unwind *self, struct frame_info *this_frame,
+ void **cache_ptr)
+{
+ static int unwind_active = 0;
+ static int recursive_unwind_detected = 0;
+ struct frame_info *next_frame;
+ struct uwscm_ephemeral_frame *data;
+ SCM ephemeral_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;
+
+ /* Recursively unwinding indicates a problem in the user's frame
+ unwinder. Detect recursion, and cause it to cancel the unwind that
+ is in progress. */
+ if (unwind_active)
+ {
+ recursive_unwind_detected = 1;
+ return 0;
+ }
+
+ ephemeral_frame = uwscm_make_ephemeral_frame (this_frame);
+ data = uwscm_ephemeral_frame_data (ephemeral_frame);
+ unwind_active = 1;
+ recursive_unwind_detected = 0;
+
+ result = gdbscm_safe_call_1 (scm_variable_ref (unwind_frame),
+ ephemeral_frame,
+ gdbscm_memory_error_p);
+
+ /* Drop the reference to this_frame, so that future use of
+ ephemeral_frame from Scheme will signal an error. */
+ uwscm_invalidate_ephemeral_frame (ephemeral_frame);
+ unwind_active = 0;
+
+ if (gdbscm_is_exception (result))
+ {
+ gdbscm_print_gdb_exception (SCM_BOOL_F, result);
+ return 0;
+ }
+
+ if (recursive_unwind_detected)
+ {
+ fprintf_filtered (gdb_stderr,
+ _("Recursion detected while unwinding frame %d."),
+ frame_relative_level (this_frame));
+ return 0;
+ }
+
+ /* The unwinder indicates success by calling
+ set-ephemeral-frame-id!. */
+ if (uwscm_ephemeral_frame_data (ephemeral_frame)->has_frame_id)
+ {
+ scm_gc_protect_object (ephemeral_frame);
+ *cache_ptr = SCM2PTR (ephemeral_frame);
+ return 1;
+ }
+
+ return 0;
+}
+
+/* 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[] =
+{
+ { "ephemeral-frame-has-id?", 1, 0, 0, uwscm_ephemeral_frame_has_id_p,
+ "\
+Return #t if the given ephemeral frame has been given a frame ID\n\
+already, or #f otherwise." },
+
+ { "set-ephemeral-frame-id!", 2, 2, 0, uwscm_set_ephemeral_frame_id_x,
+ "\
+Set the identifier on an ephemeral frame, thereby taking responsibility for\n\
+unwinding this frame.\n\
+\n\
+This function takes two required arguments and two optional arguments.\n\
+The first argument is the ephemeral frame that is being unwound, as a\n\
+<gdb:ephemeral-frame>. The rest of the arguments are used to build an\n\
+identifier for the frame.\n\
+\n\
+Ephemeral frame objects are created by the custom unwinder interface, and\n\
+initially have no frame identifier. A frame identifier is a unique name\n\
+for a frame that remains valid as long as the frame itself is valid.\n\
+Usually the frame identifier is built from from the frame's stack address\n\
+and code address. The stack address, passed as the second argument,\n\
+should normally be a pointer to the new end of the stack when the function\n\
+was called, as a GDB value. Similarly the code address, the third\n\
+argument, should be given as the address of the entry point of the\n\
+function.\n\
+\n\
+For most architectures, it is sufficient to just specify just the stack\n\
+and code pointers. Some architectures have another stack or some other\n\
+frame state store, like ia64, and they need an additional address, which\n\
+may be passed as the fourth argument.\n\
+\n\
+It is possible to create a frame ID with just a stack address, but it's\n\
+better to specify a code address as well if possible."},
+
+ { "ephemeral-frame-read-register", 2, 0, 0,
+ uwscm_ephemeral_frame_read_register,
+ "\
+Return the value of a register in an ephemeral frame.\n\
+\n\
+ Arguments: <gdb:ephemeral-frame> string" },
+
+ { "ephemeral-frame-add-saved-register!", 3, 0, 0,
+ uwscm_ephemeral_frame_add_saved_register_x,
+ "\
+Set the saved value of a register in a ephemeral frame.\n\
+\n\
+After reading an ephemeral frame's registers and determining that it\n\
+can handle the frame, an unwinder will call this function to record\n\
+saved registers. The values of the saved registers logically belong\n\
+to the frame that is older than the ephemeral frame being unwound, not\n\
+the ephemeral frame itself.\n\
+\n\
+The first argument should be a <gdb:ephemeral-frame> 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. Alternately, passing #f\n\
+as the value will mark the register as unavailable." },
+
+ 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 ephemeral frame type and register
+ gdbscm_load_frame_unwinders for calling by (gdb frame-unwinders). */
+
+void
+gdbscm_initialize_frame_unwinders (void)
+{
+ ephemeral_frame_smob_tag =
+ gdbscm_make_smob_type (ephemeral_frame_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 1891237..9037c92 100644
--- a/gdb/guile/scm-symbol.c
+++ b/gdb/guile/scm-symbol.c
@@ -599,7 +599,9 @@ gdbscm_lookup_symbol (SCM name_scm, SCM rest)
TRY_CATCH (except, RETURN_MASK_ALL)
{
- 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);
}
GDBSCM_HANDLE_GDB_EXCEPTION_WITH_CLEANUPS (except, cleanups);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 2265764..6666896 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2015-03-06 Andy Wingo <wingo@igalia.com>
+
+ * 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.
+
2015-02-20 Andy Wingo <wingo@igalia.com>
* gdb.guile/scm-frame.exp: Add frame-read-register tests, modelled
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..96981ed
--- /dev/null
+++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder-gdb.scm.in
@@ -0,0 +1,32 @@
+;; 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 <http://www.gnu.org/licenses/>.
+
+;; 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 (objfile (current-objfile)))
+ (define (unwind-frame frame)
+ #f)
+ (define (add-unwinder! name priority)
+ (add-frame-unwinder! (make-frame-unwinder name unwind-frame
+ #:priority priority
+ #:objfile objfile)))
+ (add-unwinder! "Auto-loaded dummy" 100)
+ (add-unwinder! "Auto-loaded dummy 2" 200))
+
+(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..82db341
--- /dev/null
+++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder.c
@@ -0,0 +1,30 @@
+int f2 (int a)
+{
+ return ++a;
+}
+
+int f1 (int a, int b)
+{
+ return f2(a) + b;
+}
+
+int block (void)
+{
+ int i = 99;
+ {
+ double i = 1.1;
+ double f = 2.2;
+ {
+ const char *i = "stuff";
+ const char *f = "foo";
+ const char *b = "bar";
+ return 0; /* Block break here. */
+ }
+ }
+}
+
+int main (int argc, char *argv[])
+{
+ block ();
+ 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..699b170
--- /dev/null
+++ b/gdb/testsuite/gdb.guile/scm-frame-unwinder.exp
@@ -0,0 +1,84 @@
+# 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 <http://www.gnu.org/licenses/>.
+
+# 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 {
+ perror "couldn't run to breakpoint"
+ return
+}
+
+# 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 (all-frame-unwinders)" \
+ ".*Dummy.*Auto-loaded dummy 2.*Synthetic.*Auto-loaded dummy.*" \
+ "all frame unwinders"
+gdb_test "guile (map frame-unwinder-priority (all-frame-unwinders))" \
+ ".*300 200 150 100.*" \
+ "all frame unwinder priorities"
+gdb_test "guile (map frame-unwinder-enabled? (all-frame-unwinders))" \
+ ".*#t #t #f #t.*" \
+ "all frame unwinders enabled?"
+
+gdb_test_no_output "guile (disable-frame-unwinder! \"Dummy\")" \
+ "disable dummy"
+gdb_test "guile (frame-unwinder-enabled? (find-frame-unwinder-by-name \"Dummy\"))"\
+ ".*#f.*" \
+ "dummy not enabled"
+gdb_test_no_output "guile (enable-frame-unwinder! \"Dummy\")" \
+ "re-enable dummy"
+gdb_test "guile (frame-unwinder-enabled? (find-frame-unwinder-by-name \"Dummy\"))"\
+ ".*#t.*" \
+ "dummy re-enabled"
+
+gdb_test_no_output "guile (enable-frame-unwinder! \"Synthetic\")" \
+ "enable synthetic unwinder"
+
+gdb_breakpoint "f2"
+gdb_continue_to_breakpoint "breakpoint at f2"
+
+gdb_test "bt 10" " f2 .*deadbeef .*deadbeef .*"
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..e5cf2fa
--- /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 <http://www.gnu.org/licenses/>.
+
+;; 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)
+
+(add-frame-unwinder!
+ (make-frame-unwinder "Dummy" dummy-unwinder #:priority 300))
+
+
+(define (synthetic-unwinder frame)
+ ;; Increment the stack pointer, set IP to 0xdeadbeef
+ (let* ((this-pc (ephemeral-frame-read-register frame "rip"))
+ (this-sp (ephemeral-frame-read-register frame "rsp")))
+ (set-ephemeral-frame-id! frame this-sp this-pc)
+ (ephemeral-frame-add-saved-register! frame "rip"
+ (value-cast (make-value #xdeadbeef)
+ (value-type this-pc)))
+ (ephemeral-frame-add-saved-register! frame "rsp" (value-add this-sp 32))))
+
+(add-frame-unwinder!
+ (make-frame-unwinder "Synthetic" synthetic-unwinder #:priority 150
+ #:enabled? #f))
--
2.1.4