From 221484c1c6871d6fa93d4338df52d03d76a436dc Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 14 Feb 2019 09:12:57 -0800
Subject: [PATCH] i386: Don't insert ENDBR after NOTE_INSN_DELETED_LABEL
NOTE_INSN_DELETED_LABEL is used to mark what used to be a 'code_label',
but was not used for other purposes than taking its address which cannot
be used as target for indirect jumps.
Since LABEL_PRESERVE_P is true only if the label address was taken, don't
set LABEL_PRESERVE_P on label used to initialize PIC register.
Tested on Linux/x86-64 with -fcf-protection.
For x86-64 libc.so on glibc master branch (commit f43b8dd55588c3),
Before: 2961 endbr64
After: 2943 endbr64
2019-05-31 H.J. Lu <hongjiu.lu@intel.com>
Hongtao Liu <hongtao.liu@intel.com>
gcc/
PR target/89355
* config/i386/i386-features.c (rest_of_insert_endbranch): Remove
NOTE_INSN_DELETED_LABEL check.
* config/i386/i386.c (ix86_init_large_pic_reg): Don't set
LABEL_PRESERVE_P.
gcc/testsuite/
PR target/89355
* gcc.target/i386/cet-label-3.c: New test.
* gcc.target/i386/cet-label-4.c: Likewise.
* gcc.target/i386/cet-label-5.c: Likewise.
---
gcc/config/i386/i386-features.c | 5 +----
gcc/config/i386/i386.c | 1 -
gcc/testsuite/gcc.target/i386/cet-label-3.c | 23 +++++++++++++++++++++
gcc/testsuite/gcc.target/i386/cet-label-4.c | 12 +++++++++++
gcc/testsuite/gcc.target/i386/cet-label-5.c | 13 ++++++++++++
5 files changed, 49 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/cet-label-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/cet-label-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/cet-label-5.c
@@ -1911,10 +1911,7 @@ rest_of_insert_endbranch (void)
continue;
}
- if ((LABEL_P (insn) && LABEL_PRESERVE_P (insn))
- || (NOTE_P (insn)
- && NOTE_KIND (insn) == NOTE_INSN_DELETED_LABEL))
- /* TODO. Check /s bit also. */
+ if (LABEL_P (insn) && LABEL_PRESERVE_P (insn))
{
cet_eb = gen_nop_endbr ();
emit_insn_after (cet_eb, insn);
@@ -1651,7 +1651,6 @@ ix86_init_large_pic_reg (unsigned int tmp_regno)
gcc_assert (Pmode == DImode);
label = gen_label_rtx ();
emit_label (label);
- LABEL_PRESERVE_P (label) = 1;
tmp_reg = gen_rtx_REG (Pmode, tmp_regno);
gcc_assert (REGNO (pic_offset_table_rtx) != tmp_regno);
emit_insn (gen_set_rip_rex64 (pic_offset_table_rtx,
new file mode 100644
@@ -0,0 +1,23 @@
+/* PR target/89355 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* { dg-final { scan-assembler-times "endbr32" 1 { target ia32 } } } */
+/* { dg-final { scan-assembler-times "endbr64" 1 { target { ! ia32 } } } } */
+int
+test (int* val)
+{
+ int status = 99;
+
+ if (!val)
+ {
+ status = 22;
+ goto end;
+ }
+
+ extern int x;
+ *val = x;
+
+ status = 0;
+end:
+ return status;
+}
new file mode 100644
@@ -0,0 +1,12 @@
+/* PR target/89355 */
+/* { dg-do compile { target { fpic && lp64 } } } */
+/* { dg-options "-O2 -fcf-protection -fPIC -mcmodel=large" } */
+/* { dg-final { scan-assembler-times "endbr64" 1 } } */
+
+extern int val;
+
+int
+test (void)
+{
+ return val;
+}
new file mode 100644
@@ -0,0 +1,13 @@
+/* PR target/89355 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection -Wno-return-local-addr" } */
+/* { dg-final { scan-assembler-times "endbr32" 1 { target ia32 } } } */
+/* { dg-final { scan-assembler-times "endbr64" 1 { target { ! ia32 } } } } */
+
+void *
+func (void)
+{
+ return &&bar;
+bar:
+ return 0;
+}
--
2.20.1