You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

59 lines
2.5 KiB

* config/i386/i386.c (ix86_emit_restore_reg_using_pop): Prototype.
(ix86_adjust_stack_and_probe_stack_clash): Use a push/pop sequence
to probe at the start of a noreturn function.
* gcc.target/i386/stack-check-12.c: New test
diff -Nrup a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
--- a/gcc/config/i386/i386.c 2017-11-03 13:35:17.641528205 -0600
+++ b/gcc/config/i386/i386.c 2017-11-03 13:37:39.489361692 -0600
@@ -64,6 +64,7 @@ along with GCC; see the file COPYING3.
#include "tree-flow.h"
static rtx legitimize_dllimport_symbol (rtx, bool);
+static void ix86_emit_restore_reg_using_pop (rtx);
#ifndef CHECK_STACK_LIMIT
#define CHECK_STACK_LIMIT (-1)
@@ -9884,8 +9885,14 @@ ix86_adjust_stack_and_probe_stack_clash
we just probe when we cross PROBE_INTERVAL. */
if (TREE_THIS_VOLATILE (cfun->decl))
{
- emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
- -GET_MODE_SIZE (word_mode)));
+ /* We can safely use any register here since we're just going to push
+ its value and immediately pop it back. But we do try and avoid
+ argument passing registers so as not to introduce dependencies in
+ the pipeline. For 32 bit we use %esi and for 64 bit we use %rax. */
+ rtx dummy_reg = gen_rtx_REG (word_mode, TARGET_64BIT ? AX_REG : SI_REG);
+ rtx insn = emit_insn (gen_push (dummy_reg));
+ RTX_FRAME_RELATED_P (insn) = 1;
+ ix86_emit_restore_reg_using_pop (dummy_reg);
emit_insn (gen_blockage ());
}
diff -Nrup a/gcc/testsuite/gcc.target/i386/stack-check-12.c b/gcc/testsuite/gcc.target/i386/stack-check-12.c
--- a/gcc/testsuite/gcc.target/i386/stack-check-12.c 1969-12-31 17:00:00.000000000 -0700
+++ b/gcc/testsuite/gcc.target/i386/stack-check-12.c 2017-11-03 13:36:15.104055651 -0600
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-clash-protection -mtune=generic -fomit-frame-pointer" } */
+/* { dg-require-effective-target supports_stack_clash_protection } */
+
+__attribute__ ((noreturn)) void exit (int);
+
+__attribute__ ((noreturn)) void
+f (void)
+{
+ asm volatile ("nop" ::: "edi");
+ exit (1);
+}
+
+/* { dg-final { scan-assembler-not "or\[ql\]" } } */
+/* { dg-final { scan-assembler "pushl %esi" { target ia32 } } } */
+/* { dg-final { scan-assembler "popl %esi" { target ia32 } } }*/
+/* { dg-final { scan-assembler "pushq %rax" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "popq %rax" { target { ! ia32 } } } }*/
+