Hi! As the following testcase shows, unwind.h on ARM can't be (starting with GCC 10) compiled with -std=c* modes, only -std=gnu* modes. The problem is it uses asm keyword, which isn't a keyword in those modes (system headers vs. non-system ones don't make a difference here). glibc and other installed headers use __asm or __asm__ keywords instead that work fine in both standard and gnu modes.
While there, as it is an installed header, I think it is also wrong to completely ignore any identifier namespace rules. The generic unwind.h defines just _Unwind* namespace identifiers plus _sleb128_t/_uleb128_t (but e.g. unlike libstdc++/glibc headers doesn't uglify operand names), the ARM unwind.h is much worse here. I've just changed the gnu_Unwind_Find_got function at least not be in user identifier namespace, but perhaps it would be good to go further and rename e.g. #define UNWIND_STACK_REG 13 #define UNWIND_POINTER_REG 12 #define FDPIC_REGNUM 9 #define STR(x) #x #define XSTR(x) STR(x) or e.g. typedef _Unwind_Reason_Code (*personality_routine) (_Unwind_State, _Unwind_Control_Block *, _Unwind_Context *); in unwind-arm-common.h. Bootstrapped/regtested on armv7hl-linux-gnueabi, ok for trunk? 2020-02-07 Jakub Jelinek <ja...@redhat.com> PR target/93615 * config/arm/unwind-arm.h (gnu_Unwind_Find_got): Rename to ... (_Unwind_gnu_Find_got): ... this. Use __asm instead of asm. Remove trailing :s in asm. Formatting fixes. (_Unwind_decode_typeinfo_ptr): Adjust caller. * gcc.dg/pr93615.c: New test. --- libgcc/config/arm/unwind-arm.h.jj 2020-01-12 11:54:38.616380172 +0100 +++ libgcc/config/arm/unwind-arm.h 2020-02-06 16:16:54.244624408 +0100 @@ -43,19 +43,15 @@ extern "C" { #endif _Unwind_Ptr __attribute__((weak)) __gnu_Unwind_Find_got (_Unwind_Ptr); -static inline _Unwind_Ptr gnu_Unwind_Find_got (_Unwind_Ptr ptr) +static inline _Unwind_Ptr _Unwind_gnu_Find_got (_Unwind_Ptr ptr) { _Unwind_Ptr res; if (__gnu_Unwind_Find_got) - res = __gnu_Unwind_Find_got (ptr); + res = __gnu_Unwind_Find_got (ptr); else - { - asm volatile ("mov %[result], r" XSTR(FDPIC_REGNUM) - : [result]"=r" (res) - : - :); - } + __asm volatile ("mov %[result], r" XSTR(FDPIC_REGNUM) + : [result] "=r" (res)); return res; } @@ -75,7 +71,7 @@ static inline _Unwind_Ptr gnu_Unwind_Fin #if __FDPIC__ /* For FDPIC, we store the offset of the GOT entry. */ /* So, first get GOT from dynamic linker and then use indirect access. */ - tmp += gnu_Unwind_Find_got (ptr); + tmp += _Unwind_gnu_Find_got (ptr); tmp = *(_Unwind_Word *) tmp; #elif (defined(linux) && !defined(__uClinux__)) || defined(__NetBSD__) \ || defined(__FreeBSD__) || defined(__fuchsia__) --- gcc/testsuite/gcc.dg/pr93615.c.jj 2020-02-06 22:40:00.921472574 +0100 +++ gcc/testsuite/gcc.dg/pr93615.c 2020-02-06 22:39:52.937591443 +0100 @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-std=c11" } */ +/* { dg-require-effective-target exceptions } */ + +#include <unwind.h> + +int +main () +{ + return 0; +} Jakub