https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83905
Bug ID: 83905
Summary: ix86_expand_epilogue modifies the copy of
cfun->machine->frame
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: mliska at suse dot cz, ubizjak at gmail dot com
Target Milestone: ---
Target: x86
Created attachment 43155
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43155&action=edit
A patch to demonstrate the ix86_expand_epilogue issue
With the patch in this bug report:
Subject: [PATCH] i386: More use reference of struct ix86_frame to avoid copy
When there is no need to make a copy of ix86_frame, we can use reference
of struct ix86_frame to avoid copy.
* config/i386/i386.c (ix86_expand_prologue): Use reference of
struct ix86_frame.
(ix86_expand_epilogue): Likewise.
I got
raised STORAGE_ERROR : stack overflow or erroneous memory access
make[5]: *** [/export/gnu/import/git/sources/gcc/gcc/ada/Make-generated.in:45:
a
da/sinfo.h] Error 1
on trunk when bootstrapping GCC with ada on x86-64. Revert the change
in ix86_expand_epilogue:
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index bfb31db8752..9eba3ffd5d6 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -14291,7 +14290,6 @@ ix86_expand_epilogue (int style)
{
struct machine_function *m = cfun->machine;
struct machine_frame_state frame_state_save = m->fs;
- struct ix86_frame frame;
bool restore_regs_via_mov;
bool using_drap;
bool restore_stub_is_tail = false;
@@ -14304,7 +14302,7 @@ ix86_expand_epilogue (int style)
}
ix86_finalize_stack_frame_flags ();
- frame = m->frame;
+ struct ix86_frame &frame = cfun->machine->frame;
m->fs.sp_realigned = stack_realign_fp;
m->fs.sp_valid = stack_realign_fp
fixed GCC bootstrap. ix86_expand_epilogue has
/* Special care must be taken for the normal return case of a function
using eh_return: the eax and edx registers are marked as saved, but
not restored along this path. Adjust the save location to match. */
if (crtl->calls_eh_return && style != 2)
frame.reg_save_offset -= 2 * UNITS_PER_WORD;
It works only if "frame" is a copy, not a reference to cfun->machine->frame.
