x86: Define LIBGCC2_UNWIND_ATTRIBUTE on ia32 [PR104781]

On Mon, Mar 07, 2022 at 07:06:28AM -0800, H.J. Lu wrote:
> Since eh_return doesn't work with stack realignment, disable SSE on
> unwind-c.c and unwind-dw2.c to avoid stack realignment with the 4-byte
> incoming stack to avoid SSE usage which is caused by

The following change does that using LIBGCC2_UNWIND_ATTRIBUTE macro instead,
for ia32 only by forcing -mgeneral-regs-only on routines that call
__builtin_eh_return in libgcc.

2022-03-09  Jakub Jelinek  <jakub@redhat.com>

	PR target/104781
	* config/i386/i386.h (LIBGCC2_UNWIND_ATTRIBUTE): Define for ia32.

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index b37d4a9966a9d4ba11950c591e4c746118e2c66c..0d28e57f8f2aec0a0d2313aa3d940c284626b682 100644 (file)
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2848,6 +2848,12 @@ extern enum attr_cpu ix86_schedule;
 #define NUM_X86_64_MS_CLOBBERED_REGS 12
 #endif
 
+/* __builtin_eh_return can't handle stack realignment, so restrict to
+   general regs in 32-bit libgcc functions that call it.  */
+#ifndef __x86_64__
+#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("general-regs-only")))
+#endif
+
 /*
 Local variables:
 version-control: t