On Wed, Nov 14, 2012 at 7:51 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> Hi,
>
> X32 uses 32-bit pointer in software. But its hardware pointer is
> 64-bit. We must use hardware pointer to unwind frames. This patch
> adds uhwptr for hardware pointer and uses it to unwind stack frames.
> Tested on Linux/x32, Linux/x86-64 and Linux/ia32. Please review it
> for upstream.
>
> Thanks.
>
>
> H.J.
> ---
> 2012-11-14 H.J. Lu <hongjiu...@intel.com>
>
> PR other/55333
> * include/sanitizer/common_interface_defs.h (uhwptr): New type
> for hardware pointer.
> * sanitizer_common/sanitizer_stacktrace.cc
> (StackTrace::FastUnwindStack):
> Replace uptr with uhwptr for frame unwind.
Can't you use the mode __unwind_word__ instead if we are compiling
with GCC? This way it will always be correct even for x86_64 and x32?
Also I think StackTrace::FastUnwindStack should never be enabled in
general for GCC since it depends on the frame pointer being enabled
which is not always true on either i686 or x86_64 and it is not very
portable at all.
Thanks,
Andrew Pinski
>
> diff --git a/libsanitizer/include/sanitizer/common_interface_defs.h
> b/libsanitizer/include/sanitizer/common_interface_defs.h
> index 4ac7609..64b8232 100644
> --- a/libsanitizer/include/sanitizer/common_interface_defs.h
> +++ b/libsanitizer/include/sanitizer/common_interface_defs.h
> @@ -46,6 +46,11 @@ typedef signed long long sptr; // NOLINT
> typedef unsigned long uptr; // NOLINT
> typedef signed long sptr; // NOLINT
> #endif // defined(_WIN64)
> +#if defined(__x86_64__)
> +typedef unsigned long long uhwptr; // NOLINT
> +#else
> +typedef uptr uhwptr; // NOLINT
> +#endif
> typedef unsigned char u8;
> typedef unsigned short u16; // NOLINT
> typedef unsigned int u32;
> diff --git a/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> b/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> index f6d7a09..915c4b8 100644
> --- a/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> +++ b/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> @@ -120,18 +120,18 @@ void StackTrace::FastUnwindStack(uptr pc, uptr bp,
> uptr stack_top, uptr stack_bottom) {
> CHECK(size == 0 && trace[0] == pc);
> size = 1;
> - uptr *frame = (uptr*)bp;
> - uptr *prev_frame = frame;
> + uhwptr *frame = (uhwptr *)bp;
> + uhwptr *prev_frame = frame;
> while (frame >= prev_frame &&
> - frame < (uptr*)stack_top - 2 &&
> - frame > (uptr*)stack_bottom &&
> + frame < (uhwptr *)stack_top - 2 &&
> + frame > (uhwptr *)stack_bottom &&
> size < max_size) {
> - uptr pc1 = frame[1];
> + uhwptr pc1 = frame[1];
> if (pc1 != pc) {
> - trace[size++] = pc1;
> + trace[size++] = (uptr) pc1;
> }
> prev_frame = frame;
> - frame = (uptr*)frame[0];
> + frame = (uhwptr *)frame[0];
> }
> }
>
