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[PATCH] Fix -fsplit-stack with non-local gotos (PR target/79494)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Uros Bizjak <ubizjak at gmail dot com>, Segher Boessenkool <segher at kernel dot crashing dot org>, Ian Lance Taylor <iant at golang dot org>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 20 Feb 2017 21:42:26 +0100
- Subject: [PATCH] Fix -fsplit-stack with non-local gotos (PR target/79494)
- Authentication-results: sourceware.org; auth=none
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
We ICE on the following testcase, because we have abnormal edges
from both __morestack call (which is before prologue) and call
to the nested function (which is in between prologue and epilogue)
to a label reachable through non-local goto. This is something
dwarf2cfi doesn't allow, it doesn't know what CFI state should
be at that label.
As __morestack really doesn't do non-local gotos and while it probably
can throw, it is never something that can be caught in the function that
calls __morestack, the following patch fixes it by telling middle-end
that __morestack can't do nl goto.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2017-02-20 Jakub Jelinek <jakub@redhat.com>
PR target/79494
* config/i386/i386.c (ix86_expand_split_stack_prologue): Call
make_reg_eh_region_note_nothrow_nononlocal on call_insn.
* config/rs6000/rs6000.c: Include except.h.
(rs6000_expand_split_stack_prologue): Call
make_reg_eh_region_note_nothrow_nononlocal on the call insn.
* gcc.dg/pr79494.c: New test.
--- gcc/config/i386/i386.c.jj 2017-02-20 13:51:22.000000000 +0100
+++ gcc/config/i386/i386.c 2017-02-20 15:26:04.184793980 +0100
@@ -15057,6 +15057,8 @@ ix86_expand_split_stack_prologue (void)
add_function_usage_to (call_insn, call_fusage);
if (!TARGET_64BIT)
add_reg_note (call_insn, REG_ARGS_SIZE, GEN_INT (0));
+ /* Indicate that this function can't jump to non-local gotos. */
+ make_reg_eh_region_note_nothrow_nononlocal (as_a <rtx_insn *> (call_insn));
/* In order to make call/return prediction work right, we now need
to execute a return instruction. See
--- gcc/config/rs6000/rs6000.c.jj 2017-02-18 14:12:36.000000000 +0100
+++ gcc/config/rs6000/rs6000.c 2017-02-20 15:47:56.602798893 +0100
@@ -66,6 +66,7 @@
#include "builtins.h"
#include "context.h"
#include "tree-pass.h"
+#include "except.h"
#if TARGET_XCOFF
#include "xcoffout.h" /* get declarations of xcoff_*_section_name */
#endif
@@ -31680,6 +31681,8 @@ rs6000_expand_split_stack_prologue (void
split_stack_return use r0. */
use_reg (&call_fusage, r0);
add_function_usage_to (insn, call_fusage);
+ /* Indicate that this function can't jump to non-local gotos. */
+ make_reg_eh_region_note_nothrow_nononlocal (insn);
emit_insn (gen_frame_load (r0, r1, info->lr_save_offset));
insn = emit_move_insn (lr, r0);
add_reg_note (insn, REG_CFA_RESTORE, lr);
--- gcc/testsuite/gcc.dg/pr79494.c.jj 2017-02-20 15:51:12.970247250 +0100
+++ gcc/testsuite/gcc.dg/pr79494.c 2017-02-20 15:52:59.753859680 +0100
@@ -0,0 +1,22 @@
+/* PR target/79494 */
+/* { dg-do compile } */
+/* { dg-require-effective-target split_stack } */
+/* { dg-options "-O2 -fsplit-stack" } */
+
+void
+foo (int a)
+{
+ __label__ lab;
+ __attribute__((noinline, noclone)) void bar (int b)
+ {
+ switch (b)
+ {
+ case 1:
+ goto lab;
+ case 2:
+ goto lab;
+ }
+ }
+ bar (a);
+lab:;
+}
Jakub