https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58372
--- Comment #15 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to David Grayson from comment #14)
> Does anyone have an idea of how to fix this bug for real? What values
> should crtl->preferred_stack_boundary crtl->stack_alignment_needed really
> have on Windows, and should they be controllable from the command-line?
> Where do they get set?
>
> --David
Reading symbols from /ssd/uros/gcc-build-xxx/gcc/cc1plus...done.
(gdb) watch x_rtl.preferred_stack_boundary
Hardware watchpoint 1: x_rtl.preferred_stack_boundary
(gdb) r
Starting program: /ssd/uros/gcc-build-xxx/gcc/cc1plus pr58372.C
Hardware watchpoint 1: x_rtl.preferred_stack_boundary
Old value = 0
New value = 32
0x0000000000b930dc in rtl_data::init_stack_alignment (this=0x23c8ac0 <x_rtl>)
at /home/uros/gcc-svn/trunk/gcc/emit-rtl.c:6636
6636 preferred_stack_boundary = STACK_BOUNDARY;
Hardware watchpoint 1: x_rtl.preferred_stack_boundary
Old value = 32
New value = 128
emit_library_call_value_1(int, rtx_def*, rtx_def*, libcall_type, machine_mode,
int, std::pair<rtx_def*, machine_mode>*) ()
at /home/uros/gcc-svn/trunk/gcc/calls.c:4744
4744 if (outmode != VOIDmode)
(gdb) list
4739 if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
4740 crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
4741
4742 /* If this kind of value comes back in memory,
4743 decide where in memory it should come back. */
4744 if (outmode != VOIDmode)
4745 {
4746 tfom = lang_hooks.types.type_for_mode (outmode, 0);
4747 if (aggregate_value_p (tfom, 0))
4748 {
This happen when building SjLj landing pads:
#0 emit_library_call_value_1(int, rtx_def*, rtx_def*, libcall_type,
machine_mode, int, std::pair<rtx_def*, machine_mode>*)
() at /home/uros/gcc-svn/trunk/gcc/calls.c:4744
#1 0x0000000000b9b36c in emit_library_call (arg1_mode=<optimized out>,
arg1=<optimized out>, outmode=E_VOIDmode,
fn_type=LCT_NORMAL, fun=<optimized out>) at
/home/uros/gcc-svn/trunk/gcc/rtl.h:4123
#2 sjlj_emit_function_enter(rtx_code_label*) () at
/home/uros/gcc-svn/trunk/gcc/except.c:1202
#3 0x0000000000b9f20a in sjlj_build_landing_pads () at
/home/uros/gcc-svn/trunk/gcc/except.c:1481
#4 finish_eh_generation() () at /home/uros/gcc-svn/trunk/gcc/except.c:1510
Adding -mpreferred-stack-boundary=2 "fixes" compilation.
If you want to experiment, try the following patch:
Index: config/i386/mingw32.h
===================================================================
--- config/i386/mingw32.h (revision 265582)
+++ config/i386/mingw32.h (working copy)
@@ -251,6 +251,10 @@
#undef CHECK_EXECUTE_STACK_ENABLED
#define CHECK_EXECUTE_STACK_ENABLED flag_setstackexecutable
+#undef PREFERRED_STACK_BOUNDARY_DEFAULT
+#define PREFERRED_STACK_BOUNDARY_DEFAULT \
+ (TARGET_64BIT ? 128 : MIN_STACK_BOUNDARY)
+
/* This matches SHLIB_SONAME and SHLIB_SOVERSION in t-cygming. */
/* This matches SHLIB_SONAME and SHLIB_SOVERSION in t-cygwin. */
#if DWARF2_UNWIND_INFO
But I don't know the details of MS ABI, so I can't tell if the patch is
correct.
