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authorTom de Vries <tdevries@suse.de>2023-02-11 09:04:51 +0100
committerTom de Vries <tdevries@suse.de>2023-02-11 09:04:51 +0100
commitaf0d0f34d8bf7482e598308b54e7ba0ae9b0c349 (patch)
treea122635588c7beebfbce5af5c0a2a45b0d12beb1
parent0a3137ce4c4b38ee8b26c09824633b827fed4cb1 (diff)
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[gdb/tdep] Don't use i386 unwinder for amd64
For i386 we have these unwinders: ... $ 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 inline INLINE_FRAME i386 epilogue NORMAL_FRAME dwarf2 NORMAL_FRAME dwarf2 signal SIGTRAMP_FRAME i386 stack tramp NORMAL_FRAME i386 sigtramp SIGTRAMP_FRAME i386 prologue NORMAL_FRAME ... and for amd64: ... $ 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 i386 epilogue NORMAL_FRAME dwarf2 NORMAL_FRAME dwarf2 signal SIGTRAMP_FRAME amd64 sigtramp SIGTRAMP_FRAME amd64 prologue NORMAL_FRAME i386 stack tramp NORMAL_FRAME i386 sigtramp SIGTRAMP_FRAME i386 prologue NORMAL_FRAME ... ISTM me there's no reason for the i386 unwinders to be there for amd64. Furthermore, there's a generic need to play around with enabling and disabling unwinders, see PR8434. Currently, that's only available for both the dwarf2 unwinders at once using "maint set dwarf unwinders on/off". If I manually disable the "amd64 epilogue" unwinder, the "i386 epilogue" unwinder becomes active and gives the wrong answer, while I'm actually interested in the result of the dwarf2 unwinder. Of course I can also manually disable the "i386 epilogue", but I take the fact that I have to do that as evidence that on amd64, the "i386 epilogue" is not only unnecessary, but in the way. Fix this by only adding the i386 unwinders if "info.bfd_arch_info->bits_per_word == 32". Note that the x32 abi (x86_64/-mx32): - has the same unwinder list as amd64 (x86_64/-m64) before this commit, - has info.bfd_arch_info->bits_per_word == 64, the same as amd64, and consequently, - has the same unwinder list as amd64 after this commit. Tested on x86_64-linux, -m64 and -m32. Not tested with -mx32. Reviewed-By: John Baldwin <jhb@freebsd.org> PR tdep/30102 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30102
-rw-r--r--gdb/i386-tdep.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 580664d..8dccae6 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -8613,7 +8613,8 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
appended to the list first, so that it supercedes the DWARF
unwinder in function epilogues (where the DWARF unwinder
currently fails). */
- frame_unwind_append_unwinder (gdbarch, &i386_epilogue_frame_unwind);
+ if (info.bfd_arch_info->bits_per_word == 32)
+ frame_unwind_append_unwinder (gdbarch, &i386_epilogue_frame_unwind);
/* Hook in the DWARF CFI frame unwinder. This unwinder is appended
to the list before the prologue-based unwinders, so that DWARF
@@ -8792,9 +8793,12 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdep-> bnd0_regnum = -1;
/* Hook in the legacy prologue-based unwinders last (fallback). */
- frame_unwind_append_unwinder (gdbarch, &i386_stack_tramp_frame_unwind);
- frame_unwind_append_unwinder (gdbarch, &i386_sigtramp_frame_unwind);
- frame_unwind_append_unwinder (gdbarch, &i386_frame_unwind);
+ if (info.bfd_arch_info->bits_per_word == 32)
+ {
+ frame_unwind_append_unwinder (gdbarch, &i386_stack_tramp_frame_unwind);
+ frame_unwind_append_unwinder (gdbarch, &i386_sigtramp_frame_unwind);
+ frame_unwind_append_unwinder (gdbarch, &i386_frame_unwind);
+ }
/* If we have a register mapping, enable the generic core file
support, unless it has already been enabled. */