From 924e2261d50475d5d185e4710620a496d1071d50 Mon Sep 17 00:00:00 2001
From: Jeff Law <law@redhat.com>
Date: Wed, 24 Jan 2018 15:13:15 -0700
Subject: [PATCH] - Fix -fstack-clash-protection codegen issue on 32 bit x86
 (#1536555)

---
 gcc.spec             |  7 +++-
 gcc7-rh1536555.patch | 98 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 1 deletion(-)
 create mode 100644 gcc7-rh1536555.patch

diff --git a/gcc.spec b/gcc.spec
index ea11ab8..8a570d2 100644
--- a/gcc.spec
+++ b/gcc.spec
@@ -4,7 +4,7 @@
 %global gcc_major 7
 # Note, gcc_release must be integer, if you want to add suffixes to
 # %{release}, append them after %{gcc_release} on Release: line.
-%global gcc_release 7
+%global gcc_release 8
 %global nvptx_tools_gitrev c28050f60193b3b95a18866a96f03334e874e78f
 %global nvptx_newlib_gitrev aadc8eb0ec43b7cd0dd2dfb484bae63c8b05ef24
 %global _unpackaged_files_terminate_build 0
@@ -237,6 +237,7 @@ Patch10: gcc7-foffload-default.patch
 Patch11: gcc7-Wno-format-security.patch
 Patch12: gcc7-aarch64-sanitizer-fix.patch
 Patch13: gcc7-rh1512529-aarch64.patch
+Patch14: gcc7-rh1536555.patch
 
 Patch1000: nvptx-tools-no-ptxas.patch
 Patch1001: nvptx-tools-build.patch
@@ -832,6 +833,7 @@ package or when debugging this package.
 %patch12 -p0 -b .aarch64-sanitizer-fix~
 %endif
 %patch13 -p0 -b .rh1512529-aarch64~
+%patch14 -p0 -b .rh1537979~
 
 cd nvptx-tools-%{nvptx_tools_gitrev}
 %patch1000 -p1 -b .nvptx-tools-no-ptxas~
@@ -3259,6 +3261,9 @@ fi
 %endif
 
 %changelog
+* Wed Jan 24 2018 Jeff Law <law@redhat.com> 7.2.1-8
+- Fix -fstack-clash-protection codegen issue on 32 bit x86 (#1536555)
+
 * Wed Jan 17 2018 Jakub Jelinek <jakub@redhat.com> 7.2.1-7
 - update from the 7 branch
   - PRs fortran/78814, fortran/82367, fortran/82841, fortran/83093,
diff --git a/gcc7-rh1536555.patch b/gcc7-rh1536555.patch
new file mode 100644
index 0000000..65714ee
--- /dev/null
+++ b/gcc7-rh1536555.patch
@@ -0,0 +1,98 @@
+diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
+index 346fb4f..f0b8346 100644
+--- gcc/config/i386/i386.c
++++ gcc/config/i386/i386.c
+@@ -12763,6 +12763,18 @@ ix86_builtin_setjmp_frame_value (void)
+   return stack_realign_fp ? hard_frame_pointer_rtx : virtual_stack_vars_rtx;
+ }
+ 
++/* Return the probing interval for -fstack-clash-protection.  */
++
++static HOST_WIDE_INT
++get_probe_interval (void)
++{
++  if (flag_stack_clash_protection)
++    return (HOST_WIDE_INT_1U
++	    << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL));
++  else
++    return (HOST_WIDE_INT_1U << STACK_CHECK_PROBE_INTERVAL_EXP);
++}
++
+ /* When using -fsplit-stack, the allocation routines set a field in
+    the TCB to the bottom of the stack plus this much space, measured
+    in bytes.  */
+@@ -12948,7 +12960,14 @@ ix86_compute_frame_layout (void)
+   to_allocate = offset - frame->sse_reg_save_offset;
+ 
+   if ((!to_allocate && frame->nregs <= 1)
+-      || (TARGET_64BIT && to_allocate >= HOST_WIDE_INT_C (0x80000000)))
++      || (TARGET_64BIT && to_allocate >= HOST_WIDE_INT_C (0x80000000))
++      /* If stack clash probing needs a loop, then it needs a
++	 scratch register.  But the returned register is only guaranteed
++	 to be safe to use after register saves are complete.  So if
++	 stack clash protections are enabled and the allocated frame is
++	 larger than the probe interval, then use pushes to save
++	 callee saved registers.  */
++      || (flag_stack_clash_protection && to_allocate > get_probe_interval ()))
+     frame->save_regs_using_mov = false;
+ 
+   if (ix86_using_red_zone ()
+@@ -13619,18 +13638,6 @@ release_scratch_register_on_entry (struct scratch_reg *sr)
+     }
+ }
+ 
+-/* Return the probing interval for -fstack-clash-protection.  */
+-
+-static HOST_WIDE_INT
+-get_probe_interval (void)
+-{
+-  if (flag_stack_clash_protection)
+-    return (HOST_WIDE_INT_1U
+-	    << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL));
+-  else
+-    return (HOST_WIDE_INT_1U << STACK_CHECK_PROBE_INTERVAL_EXP);
+-}
+-
+ /* Emit code to adjust the stack pointer by SIZE bytes while probing it.
+ 
+    This differs from the next routine in that it tries hard to prevent
+@@ -14558,12 +14565,11 @@ ix86_expand_prologue (void)
+       && (flag_stack_check == STATIC_BUILTIN_STACK_CHECK
+ 	  || flag_stack_clash_protection))
+     {
+-      /* This assert wants to verify that integer registers were saved
+-	 prior to probing.  This is necessary when probing may be implemented
+-	 as a function call (Windows).  It is not necessary for stack clash
+-	 protection probing.  */
+-      if (!flag_stack_clash_protection)
+-	gcc_assert (int_registers_saved);
++      /* We expect the GP registers to be saved when probes are used
++	 as the probing sequences might need a scratch register and
++	 the routine to allocate one assumes the integer registers
++	 have already been saved.  */
++      gcc_assert (int_registers_saved);
+ 
+       if (flag_stack_clash_protection)
+ 	{
+diff --git a/gcc/testsuite/gcc.target/i386/pr83994.c b/gcc/testsuite/gcc.target/i386/pr83994.c
+new file mode 100644
+index 0000000..dc0b7cb
+--- /dev/null
++++ gcc/testsuite/gcc.target/i386/pr83994.c
+@@ -0,0 +1,16 @@
++/* { dg-do compile } */
++/* { dg-options "-O2 -march=i686 -fpic -fstack-clash-protection" } */
++/* { dg-require-effective-target ia32 } */
++
++void f1 (char *);
++
++__attribute__ ((regparm (3)))
++int
++f2 (int arg1, int arg2, int arg3)
++{
++  char buf[16384];
++  f1 (buf);
++  f1 (buf);
++  return 0;
++}
++