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[PATCH] 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: Thu, 05 Mar 2015 16:57:53 +0100
- Subject: [PATCH] Add Guile frame unwinder interface
- Authentication-results: sourceware.org; auth=none
Hi,
This is an implementation of a frame unwinder interface in the spirit of
Alexander's work in this thread:
http://thread.gmane.org/gmane.comp.gdb.patches/103360/focus=105202
No documentation yet, and I am still wondering how to test it
appropriately. However it does seem some feedback could be useful
before I document the wrong thing; particualarly I would like feedback
on the changes to frame-unwind.c and frame.c.
However happily it does work in V8; eliding some helpers, the
implementation looks like this:
(use-modules (gdb frame-unwinders))
(define (unwind-v8-frame frame)
(let ((isolate (cached-current-isolate)))
(when isolate
(let* ((this-pc (ephemeral-frame-read-register frame "rip"))
(this-fp (ephemeral-frame-read-register frame "rbp"))
(code (lookup-code-for-pc this-pc isolate)))
(when code
(set-ephemeral-frame-id! frame this-fp (code-instruction-start code))
(let* ((type (if (code-optimized? code) 'javascript 'optimized))
(prev-pc-address (compute-standard-frame-pc-address this-fp))
(prev-sp (compute-frame-older-sp this-fp type))
(prev-fp (compute-standard-frame-older-fp this-fp))
(prev-pc (value-dereference prev-pc-address)))
(ephemeral-frame-add-saved-register! frame "rsp" prev-sp)
(ephemeral-frame-add-saved-register! frame "rbp" prev-fp)
(ephemeral-frame-add-saved-register! frame "rip" prev-pc)))))))
(define* (install-frame-unwinders #:optional (objfile (current-objfile)))
(add-frame-unwinder!
(make-frame-unwinder "guile-v8-frame-unwinder" unwind-v8-frame)))
And most happily, it requires no changes in V8 itself. Yaaay :) With
an appropriate frame filter, a backtrace looks like this:
#0 0x00000d3c5b0661a1 in TestCase () at /hack/v8/test/mjsunit/debug-step-4-in-frame.js:94
#1 0x00000d3c5b06a3d3 in () at /hack/v8/test/mjsunit/debug-step-4-in-frame.js:112
#2 0x00000d3c5b02c620 in [internal frame] ()
#3 0x00000d3c5b014d31 in [entry frame] ()
#4 0x0000000000b4e949 in v8::internal::Invoke([...]) at ../src/execution.cc:128
#5 0x0000000000b4ed23 in v8::internal::Execution::Call([...]) at ../src/execution.cc:179
#6 0x0000000000a3f813 in v8::Script::Run([...]) at ../src/api.cc:1514
#7 0x0000000000a149fa in v8::Shell::ExecuteString([...]) at ../src/d8.cc:281
#8 0x0000000000a194eb in v8::SourceGroup::Execute([...]) at ../src/d8.cc:1213
#9 0x0000000000a1a128 in v8::Shell::RunMain([...]) at ../src/d8.cc:1448
#10 0x0000000000a1efdc in v8::Shell::Main([...]) at ../src/d8.cc:1721
#11 0x0000000000a1f143 in main([...]) at ../src/d8.cc:1757
instead of this:
#0 0x00000d3c5b0661a1 in ?? ()
#1 0x0000000002404940 in ?? ()
#2 0x0000219b8fc5d779 in ?? ()
#3 0x000018a8ddbf01d9 in ?? ()
#4 0x0000219b8fc62a81 in ?? ()
#5 0x000018a8ddbf0179 in ?? ()
#6 0x00007fffffffd500 in ?? ()
#7 0x00000d3c5b06a3d3 in ?? ()
#8 0x00001df7db238fb1 in ?? ()
#9 0x0000000000000000 in ?? ()
Yaaaaaaaaaaay :)
Regards,
Andy
>From 948e1bba3bd08fba22c44e4afe18436d84220147 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/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 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.
---
gdb/ChangeLog | 32 ++
gdb/Makefile.in | 6 +
gdb/data-directory/Makefile.in | 2 +
gdb/frame-unwind.c | 43 ++-
gdb/frame-unwind.h | 7 +-
gdb/frame.c | 13 +
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 +-
11 files changed, 882 insertions(+), 6 deletions(-)
create mode 100644 gdb/guile/lib/gdb/frame-unwinders.scm
create mode 100644 gdb/guile/scm-frame-unwinder.c
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/frame-unwind.c b/gdb/frame-unwind.c
index e73650a..67f19ec 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -129,6 +129,33 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
gdb_assert_not_reached ("frame_unwind_try_unwinder");
}
+/* Nonzero if we are finding the unwinder for the innermost frame. */
+static int unwinding_innermost_frame = 0;
+
+static void
+innermost_frame_unwind_begin (void)
+{
+ if (unwinding_innermost_frame)
+ internal_error (__FILE__, __LINE__,
+ _("Recursion detected while unwinding innermost frame."));
+
+ unwinding_innermost_frame = 1;
+}
+
+static void
+innermost_frame_unwind_end (void)
+{
+ gdb_assert (unwinding_innermost_frame);
+
+ unwinding_innermost_frame = 0;
+}
+
+int
+frame_unwind_is_unwinding_innermost_frame (void)
+{
+ return unwinding_innermost_frame;
+}
+
/* Iterate through sniffers for THIS_FRAME frame until one returns with an
unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set
by this function. Possibly initialize THIS_CACHE. */
@@ -141,23 +168,30 @@ frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
struct frame_unwind_table_entry *entry;
const struct frame_unwind *unwinder_from_target;
+ if (frame_relative_level (this_frame) == 0)
+ innermost_frame_unwind_begin ();
+
unwinder_from_target = target_get_unwinder ();
if (unwinder_from_target != NULL
&& frame_unwind_try_unwinder (this_frame, this_cache,
unwinder_from_target))
- return;
+ goto done;
unwinder_from_target = target_get_tailcall_unwinder ();
if (unwinder_from_target != NULL
&& frame_unwind_try_unwinder (this_frame, this_cache,
unwinder_from_target))
- return;
+ goto done;
for (entry = table->list; entry != NULL; entry = entry->next)
if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder))
- return;
+ goto done;
internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed"));
+
+ done:
+ if (frame_relative_level (this_frame) == 0)
+ innermost_frame_unwind_end ();
}
/* A default frame sniffer which always accepts the frame. Used by
@@ -249,7 +283,8 @@ 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..7f12211 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 a nonzero if we are in the process of finding an unwinder for the
+ innermost frame. See the comments in get_current_frame(). */
+
+extern int frame_unwind_is_unwinding_innermost_frame (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..46bb8a7 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -2209,6 +2209,19 @@ get_prev_frame (struct frame_info *this_frame)
return NULL;
}
+ /* Unwinders implemented in Python or Scheme could end up calling a GDB
+ function that gets the current frame, for example to get the current
+ architecture. When in the process of unwinding the innermost frame, this
+ would cause unbounded recursion. Instead short-circuit the computation,
+ which will cause callers to fall back to the sentinel frame. */
+ if (this_frame->level == -1
+ && frame_unwind_is_unwinding_innermost_frame ())
+ {
+ frame_debug_got_null_frame (this_frame,
+ "recursive unwind of innermost frame");
+ 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);
--
2.1.4