commit 33839c8f8aa7857cc5f22ddb3f0960999cb0dfc7

Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>

Date:   Wed Jan 31 05:02:30 2018 +0000

            PR target/84064

            * i386.c (ix86_adjust_stack_and_probe_stack_clash): New argument

            INT_REGISTERS_SAVED.  Check it prior to calling

            get_scratch_register_on_entry.

            (ix86_adjust_stack_and_probe): Similarly.

            (ix86_emit_probe_stack_range): Similarly.

            (ix86_expand_prologue): Corresponding changes.

            PR target/84064

            * gcc.target/i386/pr84064: New test.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c

index 5230227..2fe2a0c 100644

--- a/gcc/config/i386/i386.c

+++ b/gcc/config/i386/i386.c

@@ -10206,10 +10206,14 @@ release_scratch_register_on_entry (struct scratch_reg *sr)

    This differs from the next routine in that it tries hard to prevent

    attacks that jump the stack guard.  Thus it is never allowed to allocate

    more than PROBE_INTERVAL bytes of stack space without a suitable

-   probe.  */

+   probe.

+

+   INT_REGISTERS_SAVED is true if integer registers have already been

+   pushed on the stack.  */

 static void

-ix86_adjust_stack_and_probe_stack_clash (const HOST_WIDE_INT size)

+ix86_adjust_stack_and_probe_stack_clash (const HOST_WIDE_INT size,

+					 const bool int_registers_saved)

 {

   struct machine_function *m = cfun->machine;

   struct ix86_frame frame;

@@ -10318,6 +10322,12 @@ ix86_adjust_stack_and_probe_stack_clash (const HOST_WIDE_INT size)

     }

   else

     {

+      /* 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);

+

       struct scratch_reg sr;

       get_scratch_register_on_entry (&sr);

@@ -10376,10 +10386,14 @@ ix86_adjust_stack_and_probe_stack_clash (const HOST_WIDE_INT size)

   emit_insn (gen_blockage ());

 }

-/* Emit code to adjust the stack pointer by SIZE bytes while probing it.  */

+/* Emit code to adjust the stack pointer by SIZE bytes while probing it.

+

+   INT_REGISTERS_SAVED is true if integer registers have already been

+   pushed on the stack.  */

 static void

-ix86_adjust_stack_and_probe (const HOST_WIDE_INT size)

+ix86_adjust_stack_and_probe (const HOST_WIDE_INT size,

+			     const bool int_registers_saved)

 {

   /* We skip the probe for the first interval + a small dope of 4 words and

      probe that many bytes past the specified size to maintain a protection

@@ -10440,6 +10454,12 @@ ix86_adjust_stack_and_probe (const HOST_WIDE_INT size)

      equality test for the loop condition.  */

   else

     {

+      /* 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);

+

       HOST_WIDE_INT rounded_size;

       struct scratch_reg sr;

@@ -10564,10 +10584,14 @@ output_adjust_stack_and_probe (rtx reg)

 }

 /* Emit code to probe a range of stack addresses from FIRST to FIRST+SIZE,

-   inclusive.  These are offsets from the current stack pointer.  */

+   inclusive.  These are offsets from the current stack pointer.

+

+   INT_REGISTERS_SAVED is true if integer registers have already been

+   pushed on the stack.  */

 static void

-ix86_emit_probe_stack_range (HOST_WIDE_INT first, HOST_WIDE_INT size)

+ix86_emit_probe_stack_range (HOST_WIDE_INT first, HOST_WIDE_INT size,

+			     const bool int_registers_saved)

 {

   /* See if we have a constant small number of probes to generate.  If so,

      that's the easy case.  The run-time loop is made up of 7 insns in the

@@ -10595,6 +10619,12 @@ ix86_emit_probe_stack_range (HOST_WIDE_INT first, HOST_WIDE_INT size)

      equality test for the loop condition.  */

   else

     {

+      /* 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);

+

       HOST_WIDE_INT rounded_size, last;

       struct scratch_reg sr;

@@ -11072,20 +11102,15 @@ ix86_expand_prologue (void)

       && (flag_stack_check == STATIC_BUILTIN_STACK_CHECK

 	  || flag_stack_clash_protection))

     {

-      /* 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)

 	{

-	  ix86_adjust_stack_and_probe_stack_clash (allocate);

+	  ix86_adjust_stack_and_probe_stack_clash (allocate,

+						   int_registers_saved);

 	  allocate = 0;

 	}

       else if (STACK_CHECK_MOVING_SP)

 	{

-	  ix86_adjust_stack_and_probe (allocate);

+	  ix86_adjust_stack_and_probe (allocate, int_registers_saved);

 	  allocate = 0;

 	}

       else

@@ -11096,9 +11121,11 @@ ix86_expand_prologue (void)

 	    size = 0x80000000 - get_stack_check_protect () - 1;

 	  if (TARGET_STACK_PROBE)

-	    ix86_emit_probe_stack_range (0, size + get_stack_check_protect ());

+	    ix86_emit_probe_stack_range (0, size + get_stack_check_protect (),

+					 int_registers_saved);

 	  else

-	    ix86_emit_probe_stack_range (get_stack_check_protect (), size);

+	    ix86_emit_probe_stack_range (get_stack_check_protect (), size,

+					 int_registers_saved);

 	}

     }

diff --git a/gcc/testsuite/gcc.target/i386/pr84064.c b/gcc/testsuite/gcc.target/i386/pr84064.c

new file mode 100644

index 0000000..01f8d9e

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/pr84064.c

@@ -0,0 +1,10 @@

+/* { dg-do compile } */

+/* { dg-options "-O2 -march=i686 -fstack-clash-protection" } */

+/* { dg-require-effective-target ia32 } */

+

+void

+f (void *p1, void *p2)

+{

+  __builtin_memcpy (p1, p2, 1000);

+}

+