* [PATCH v2 2/5] [gdb/tdep] Fix amd64/i386_stack_frame_destroyed_p
2023-02-13 14:23 [PATCH v2 0/5] [gdb/symtab] Assume epilogue unwind info is valid unless gcc < 4.5.0 Tom de Vries
2023-02-13 14:23 ` [PATCH v2 1/5] [gdb/symtab] Factor out compunit_epilogue_unwind_valid Tom de Vries
@ 2023-02-13 14:23 ` Tom de Vries
2023-02-13 14:23 ` [PATCH v2 3/5] [gdb/tdep] Add amd64/i386 epilogue override unwinders Tom de Vries
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Tom de Vries @ 2023-02-13 14:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
The use of compunit_epilogue_unwind_valid in both amd64_stack_frame_destroyed_p
and i386_stack_frame_destroyed_p is problematic, in the sense that the
functions no longer match their documented behaviour.
Fix this by moving the use of compunit_epilogue_unwind_valid to
amd64_epilogue_frame_sniffer and i386_epilogue_frame_sniffer. NFC.
---
gdb/amd64-tdep.c | 19 ++++++++++++-------
gdb/i386-tdep.c | 20 ++++++++++++--------
2 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index d2e683b6fa8..0ec9b23922d 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2903,9 +2903,6 @@ amd64_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
gdb_byte insn;
- if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
- return 0;
-
if (target_read_memory (pc, &insn, 1))
return 0; /* Can't read memory at pc. */
@@ -2920,11 +2917,19 @@ amd64_epilogue_frame_sniffer (const struct frame_unwind *self,
frame_info_ptr this_frame,
void **this_prologue_cache)
{
- if (frame_relative_level (this_frame) == 0)
- return amd64_stack_frame_destroyed_p (get_frame_arch (this_frame),
- get_frame_pc (this_frame));
- else
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ CORE_ADDR pc = get_frame_pc (this_frame);
+
+ if (frame_relative_level (this_frame) != 0)
+ /* We're not in the inner frame, so assume we're not in an epilogue. */
return 0;
+
+ if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
+ /* Don't override the symtab unwinders. */
+ return 0;
+
+ /* Check whether we're in an epilogue. */
+ return amd64_stack_frame_destroyed_p (gdbarch, pc);
}
static struct amd64_frame_cache *
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 3fe548d8c68..5e797d098e8 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -2219,10 +2219,6 @@ static int
i386_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
gdb_byte insn;
-
- if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
- return 0;
-
if (target_read_memory (pc, &insn, 1))
return 0; /* Can't read memory at pc. */
@@ -2237,11 +2233,19 @@ i386_epilogue_frame_sniffer (const struct frame_unwind *self,
frame_info_ptr this_frame,
void **this_prologue_cache)
{
- if (frame_relative_level (this_frame) == 0)
- return i386_stack_frame_destroyed_p (get_frame_arch (this_frame),
- get_frame_pc (this_frame));
- else
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ CORE_ADDR pc = get_frame_pc (this_frame);
+
+ if (frame_relative_level (this_frame) != 0)
+ /* We're not in the inner frame, so assume we're not in an epilogue. */
+ return 0;
+
+ if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
+ /* Don't override the symtab unwinders. */
return 0;
+
+ /* Check whether we're in an epilogue. */
+ return i386_stack_frame_destroyed_p (gdbarch, pc);
}
static struct i386_frame_cache *
--
2.35.3
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCH v2 3/5] [gdb/tdep] Add amd64/i386 epilogue override unwinders
2023-02-13 14:23 [PATCH v2 0/5] [gdb/symtab] Assume epilogue unwind info is valid unless gcc < 4.5.0 Tom de Vries
2023-02-13 14:23 ` [PATCH v2 1/5] [gdb/symtab] Factor out compunit_epilogue_unwind_valid Tom de Vries
2023-02-13 14:23 ` [PATCH v2 2/5] [gdb/tdep] Fix amd64/i386_stack_frame_destroyed_p Tom de Vries
@ 2023-02-13 14:23 ` Tom de Vries
2023-02-13 14:23 ` [PATCH v2 4/5] [gdb/symtab] Trust epilogue unwind info for unknown producer (-g0 case) Tom de Vries
2023-02-13 14:23 ` [PATCH v2 5/5] [gdb/symtab] Trust epilogue unwind info for unknown or non-gcc producer Tom de Vries
4 siblings, 0 replies; 9+ messages in thread
From: Tom de Vries @ 2023-02-13 14:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
For amd64 the current frame-unwinders are:
...
$ gdb -q -batch -ex "set arch i386:x86-64" -ex "maint info frame-unwinders"
The target architecture is set to "i386:x86-64".
dummy DUMMY_FRAME
dwarf2 tailcall TAILCALL_FRAME
inline INLINE_FRAME
python NORMAL_FRAME
amd64 epilogue NORMAL_FRAME
dwarf2 NORMAL_FRAME
dwarf2 signal SIGTRAMP_FRAME
amd64 sigtramp SIGTRAMP_FRAME
amd64 prologue NORMAL_FRAME
...
For a -g0 -fasynchronous-unwind-tables exec (without .debug_info but with
.eh_frame section), we'd like to start using the dwarf2 unwinder instead of
the "amd64 epilogue" unwinder, by returning true in
compunit_epilogue_unwind_valid for cust == nullptr.
But we'd run into the following problem for a -g0
-fno-asynchronous-unwind-tables (without .debug_info and .eh_frame section)
exec:
- the "amd64 epilogue" unwinder would not run
(because compunit_epilogue_unwind_valid () == true)
- the dwarf2 unwinder would also not run
(because there's no .eh_frame info).
Fix this by:
- renaming the "amd64 epilogue" unwinder to "amd64 epilogue override", and
- adding a fallback "amd64 epilogue" after the dwarf unwinders,
while making sure that only one of the two is active. Likewise for i386. NFC.
For amd64, this results in this change:
...
$ gdb -q -batch -ex "set arch i386:x86-64" -ex "maint info frame-unwinders"
The target architecture is set to "i386:x86-64".
dummy DUMMY_FRAME
dwarf2 tailcall TAILCALL_FRAME
inline INLINE_FRAME
python NORMAL_FRAME
-amd64 epilogue NORMAL_FRAME
+amd64 epilogue override NORMAL_FRAME
dwarf2 NORMAL_FRAME
dwarf2 signal SIGTRAMP_FRAME
+amd64 epilogue NORMAL_FRAME
amd64 sigtramp SIGTRAMP_FRAME
amd64 prologue NORMAL_FRAME
...
And for i386:
...
$ gdb -q -batch -ex "set arch i386" -ex "maint info frame-unwinders"
The target architecture is set to "i386".
dummy DUMMY_FRAME
dwarf2 tailcall TAILCALL_FRAME
iline INLINE_FRAME
-i386 epilogue NORMAL_FRAME
+i386 epilogue override NORMAL_FRAME
dwarf2 NORMAL_FRAME
dwarf2 signal SIGTRAMP_FRAME
+i386 epilogue NORMAL_FRAME
i386 stack tramp NORMAL_FRAME
i386 sigtramp SIGTRAMP_FRAME
i386 prologue NORMAL_FRAME
...
---
gdb/amd64-tdep.c | 58 +++++++++++++++++++++++++++++++++++++++++------
gdb/i386-tdep.c | 59 ++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 103 insertions(+), 14 deletions(-)
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 0ec9b23922d..c0c62bdd696 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2913,9 +2913,9 @@ amd64_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
}
static int
-amd64_epilogue_frame_sniffer (const struct frame_unwind *self,
- frame_info_ptr this_frame,
- void **this_prologue_cache)
+amd64_epilogue_frame_sniffer_1 (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache, bool override_p)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
CORE_ADDR pc = get_frame_pc (this_frame);
@@ -2924,14 +2924,45 @@ amd64_epilogue_frame_sniffer (const struct frame_unwind *self,
/* We're not in the inner frame, so assume we're not in an epilogue. */
return 0;
- if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
- /* Don't override the symtab unwinders. */
- return 0;
+ bool unwind_valid_p
+ = compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc));
+ if (override_p)
+ {
+ if (unwind_valid_p)
+ /* Don't override the symtab unwinders, skip
+ "amd64 epilogue override". */
+ return 0;
+ }
+ else
+ {
+ if (!unwind_valid_p)
+ /* "amd64 epilogue override" unwinder already ran, skip
+ "amd64 epilogue". */
+ return 0;
+ }
/* Check whether we're in an epilogue. */
return amd64_stack_frame_destroyed_p (gdbarch, pc);
}
+static int
+amd64_epilogue_override_frame_sniffer (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache)
+{
+ return amd64_epilogue_frame_sniffer_1 (self, this_frame, this_prologue_cache,
+ true);
+}
+
+static int
+amd64_epilogue_frame_sniffer (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache)
+{
+ return amd64_epilogue_frame_sniffer_1 (self, this_frame, this_prologue_cache,
+ false);
+}
+
static struct amd64_frame_cache *
amd64_epilogue_frame_cache (frame_info_ptr this_frame, void **this_cache)
{
@@ -3000,6 +3031,17 @@ amd64_epilogue_frame_this_id (frame_info_ptr this_frame,
(*this_id) = frame_id_build (cache->base + 16, cache->pc);
}
+static const struct frame_unwind amd64_epilogue_override_frame_unwind =
+{
+ "amd64 epilogue override",
+ NORMAL_FRAME,
+ amd64_epilogue_frame_unwind_stop_reason,
+ amd64_epilogue_frame_this_id,
+ amd64_frame_prev_register,
+ NULL,
+ amd64_epilogue_override_frame_sniffer
+};
+
static const struct frame_unwind amd64_epilogue_frame_unwind =
{
"amd64 epilogue",
@@ -3257,7 +3299,9 @@ amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
/* Hook the function epilogue frame unwinder. This unwinder is
appended to the list first, so that it supercedes the other
unwinders in function epilogues. */
- frame_unwind_prepend_unwinder (gdbarch, &amd64_epilogue_frame_unwind);
+ frame_unwind_prepend_unwinder (gdbarch, &amd64_epilogue_override_frame_unwind);
+
+ frame_unwind_append_unwinder (gdbarch, &amd64_epilogue_frame_unwind);
/* Hook the prologue-based frame unwinders. */
frame_unwind_append_unwinder (gdbarch, &amd64_sigtramp_frame_unwind);
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 5e797d098e8..d765c1e95d7 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -2229,9 +2229,9 @@ i386_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
}
static int
-i386_epilogue_frame_sniffer (const struct frame_unwind *self,
- frame_info_ptr this_frame,
- void **this_prologue_cache)
+i386_epilogue_frame_sniffer_1 (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache, bool override_p)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
CORE_ADDR pc = get_frame_pc (this_frame);
@@ -2240,14 +2240,45 @@ i386_epilogue_frame_sniffer (const struct frame_unwind *self,
/* We're not in the inner frame, so assume we're not in an epilogue. */
return 0;
- if (compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc)))
- /* Don't override the symtab unwinders. */
- return 0;
+ bool unwind_valid_p
+ = compunit_epilogue_unwind_valid (find_pc_compunit_symtab (pc));
+ if (override_p)
+ {
+ if (unwind_valid_p)
+ /* Don't override the symtab unwinders, skip
+ "i386 epilogue override". */
+ return 0;
+ }
+ else
+ {
+ if (!unwind_valid_p)
+ /* "i386 epilogue override" unwinder already ran, skip
+ "i386 epilogue". */
+ return 0;
+ }
/* Check whether we're in an epilogue. */
return i386_stack_frame_destroyed_p (gdbarch, pc);
}
+static int
+i386_epilogue_override_frame_sniffer (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache)
+{
+ return i386_epilogue_frame_sniffer_1 (self, this_frame, this_prologue_cache,
+ true);
+}
+
+static int
+i386_epilogue_frame_sniffer (const struct frame_unwind *self,
+ frame_info_ptr this_frame,
+ void **this_prologue_cache)
+{
+ return i386_epilogue_frame_sniffer_1 (self, this_frame, this_prologue_cache,
+ false);
+}
+
static struct i386_frame_cache *
i386_epilogue_frame_cache (frame_info_ptr this_frame, void **this_cache)
{
@@ -2320,6 +2351,17 @@ i386_epilogue_frame_prev_register (frame_info_ptr this_frame,
return i386_frame_prev_register (this_frame, this_cache, regnum);
}
+static const struct frame_unwind i386_epilogue_override_frame_unwind =
+{
+ "i386 epilogue override",
+ NORMAL_FRAME,
+ i386_epilogue_frame_unwind_stop_reason,
+ i386_epilogue_frame_this_id,
+ i386_epilogue_frame_prev_register,
+ NULL,
+ i386_epilogue_override_frame_sniffer
+};
+
static const struct frame_unwind i386_epilogue_frame_unwind =
{
"i386 epilogue",
@@ -8616,13 +8658,16 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
unwinder in function epilogues (where the DWARF unwinder
currently fails). */
if (info.bfd_arch_info->bits_per_word == 32)
- frame_unwind_append_unwinder (gdbarch, &i386_epilogue_frame_unwind);
+ frame_unwind_append_unwinder (gdbarch, &i386_epilogue_override_frame_unwind);
/* Hook in the DWARF CFI frame unwinder. This unwinder is appended
to the list before the prologue-based unwinders, so that DWARF
CFI info will be used if it is available. */
dwarf2_append_unwinders (gdbarch);
+ if (info.bfd_arch_info->bits_per_word == 32)
+ frame_unwind_append_unwinder (gdbarch, &i386_epilogue_frame_unwind);
+
frame_base_set_default (gdbarch, &i386_frame_base);
/* Pseudo registers may be changed by amd64_init_abi. */
--
2.35.3
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCH v2 4/5] [gdb/symtab] Trust epilogue unwind info for unknown producer (-g0 case)
2023-02-13 14:23 [PATCH v2 0/5] [gdb/symtab] Assume epilogue unwind info is valid unless gcc < 4.5.0 Tom de Vries
` (2 preceding siblings ...)
2023-02-13 14:23 ` [PATCH v2 3/5] [gdb/tdep] Add amd64/i386 epilogue override unwinders Tom de Vries
@ 2023-02-13 14:23 ` Tom de Vries
2023-02-13 14:23 ` [PATCH v2 5/5] [gdb/symtab] Trust epilogue unwind info for unknown or non-gcc producer Tom de Vries
4 siblings, 0 replies; 9+ messages in thread
From: Tom de Vries @ 2023-02-13 14:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
For a -g0 -fasynchronous-unwind-tables exec (without .debug_info but with
.eh_frame section), start using the dwarf2 unwinder instead of the
"amd64 epilogue override" unwinder, by returning true in
compunit_epilogue_unwind_valid for cust == nullptr.
This has effect both on the amd64 and i386 targets, but only add amd64
test-case gdb.base/unwind-on-each-insn-amd64-2.exp.
---
gdb/symtab.h | 4 +-
.../gdb.base/unwind-on-each-insn-amd64-2.exp | 52 ++++++++++++++++++
.../gdb.base/unwind-on-each-insn-amd64-2.s | 54 +++++++++++++++++++
3 files changed, 108 insertions(+), 2 deletions(-)
create mode 100644 gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.exp
create mode 100644 gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.s
diff --git a/gdb/symtab.h b/gdb/symtab.h
index cd6b5f722fd..17d2746fd48 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -1924,9 +1924,9 @@ static inline bool
compunit_epilogue_unwind_valid (struct compunit_symtab *cust)
{
/* In absence of producer information, assume epilogue unwind info is
- invalid. */
+ valid. */
if (cust == nullptr)
- return false;
+ return true;
return cust->epilogue_unwind_valid ();
}
diff --git a/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.exp b/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.exp
new file mode 100644
index 00000000000..c8a94ccef4f
--- /dev/null
+++ b/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.exp
@@ -0,0 +1,52 @@
+# Copyright 2023 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/>. */
+
+# Check that epilogue unwind info is used, even if no debug info is available.
+
+require is_x86_64_m64_target
+
+set srcfile_flags {debug}
+set srcfile2_flags {nodebug}
+
+if [info exists COMPILE] {
+ # Make sure that we use .eh_frame info, by generating it
+ # using -fasynchronous-unwind-tables.
+ if { [gdb_can_simple_compile fasynchronous-unwind-tables \
+ { void foo () { } } object -fasynchronous-unwind-tables] } {
+ lappend srcfile2_flags additional_flags=-fasynchronous-unwind-tables
+ } else {
+ unsupported "required: .eh_frame"
+ return
+ }
+ standard_testfile unwind-on-each-insn.c unwind-on-each-insn-foo.c
+ # When updating the .s file, use these flags to generate the file:
+ #lappend srcfile2_flags additional_flags=-save-temps
+ #lappend srcfile2_flags additional_flags=-dA
+ # and do the following:
+ # - copy it in place, run the test-case and verify that all tests pass.
+ # - confuse the amd64 epilogue unwinder by inserting the following
+ # in foo:
+ # nop
+ # + pushq $.L1
+ # + ret
+ # + .L1:
+ # + nop
+ # popq %rbp
+ # - verify that the test-case passes.
+} else {
+ standard_testfile unwind-on-each-insn.c .s
+}
+
+source $srcdir/$subdir/unwind-on-each-insn.exp.tcl
diff --git a/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.s b/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.s
new file mode 100644
index 00000000000..c141f71817c
--- /dev/null
+++ b/gdb/testsuite/gdb.base/unwind-on-each-insn-amd64-2.s
@@ -0,0 +1,54 @@
+ .file "unwind-on-each-insn-foo.c"
+ .text
+ .globl foo
+ .type foo, @function
+foo:
+.LFB0:
+ .cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset 6, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register 6
+ movq %rdi, -8(%rbp)
+ nop
+ pushq $.L1
+ ret
+.L1:
+ nop
+ popq %rbp
+ .cfi_def_cfa 7, 8
+# SUCC: EXIT [100.0%]
+ ret
+ .cfi_endproc
+.LFE0:
+ .size foo, .-foo
+ .globl bar
+ .type bar, @function
+bar:
+.LFB1:
+ .cfi_startproc
+# BLOCK 2 seq:0
+# PRED: ENTRY (FALLTHRU)
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset 6, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register 6
+ subq $8, %rsp
+ movq %rdi, -8(%rbp)
+ movq -8(%rbp), %rax
+ movq %rax, %rdi
+ call foo
+ nop
+ leave
+ .cfi_def_cfa 7, 8
+# SUCC: EXIT [100.0%]
+ ret
+ .cfi_endproc
+.LFE1:
+ .size bar, .-bar
+ .ident "GCC: (SUSE Linux) 7.5.0"
+ .section .note.GNU-stack,"",@progbits
--
2.35.3
^ permalink raw reply [flat|nested] 9+ messages in thread