* Richard Earnshaw: > On 11/07/2023 10:37, Florian Weimer via Gcc-patches wrote: >> libgcc/ >> * config/aarch64/aarch64-unwind.h >> (aarch64_cie_signed_with_b_key): >> Add missing const qualifier. Cast from const unsigned char * >> to const char *. Use __builtin_strchr to avoid an implicit >> function declaration. >> * config/aarch64/linux-unwind.h (aarch64_fallback_frame_state): >> Add missing cast. >> --- >> diff --git a/libgcc/config/aarch64/linux-unwind.h >> b/libgcc/config/aarch64/linux-unwind.h >> index 00eba866049..93da7a9537d 100644 >> --- a/libgcc/config/aarch64/linux-unwind.h >> +++ b/libgcc/config/aarch64/linux-unwind.h >> @@ -77,7 +77,7 @@ aarch64_fallback_frame_state (struct _Unwind_Context >> *context, >> } >> rt_ = context->cfa; >> - sc = &rt_->uc.uc_mcontext; >> + sc = (struct sigcontext *) &rt_->uc.uc_mcontext; >> /* This define duplicates the definition in aarch64.md */ >> #define SP_REGNUM 31 >> > > This looks somewhat dubious. I'm not particularly familiar with the > kernel headers, but a quick look suggests an mcontext_t is nothing > like a sigcontext_t. So isn't the cast just papering over some more > fundamental problem?
I agree it looks dubious. Note that it's struct sigcontext, not (not-struct) sigcontext_t. I don't know why the uc_mcontext members aren't accessed directly, so I can't really write a good comment about it. Obviously it works quite well as-is. 8-) Similar code is present in many, many Linux targets. Thanks, Florian
