gcc/gcc7-pr84064.patch

2018-01-30  Jeff Law  <law@redhat.com>

	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.

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

--- gcc/config/i386/i386.c
+++ gcc/config/i386/i386.c
@@ -12591,10 +12591,14 @@ 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;
 
@@ -12700,6 +12704,12 @@ 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);
 
@@ -12758,10 +12768,14 @@ 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
@@ -12822,6 +12836,12 @@ 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;
 
@@ -12949,10 +12969,14 @@ 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 6 insns in the
@@ -12980,6 +13004,12 @@ 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;
 
@@ -13733,15 +13763,10 @@ 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)
@@ -13749,7 +13774,7 @@ ix86_expand_prologue (void)
 	  if (!(crtl->is_leaf && !cfun->calls_alloca
 		&& allocate <= get_probe_interval ()))
 	    {
-	      ix86_adjust_stack_and_probe (allocate);
+	      ix86_adjust_stack_and_probe (allocate, int_registers_saved);
 	      allocate = 0;
 	    }
 	}
@@ -13765,11 +13790,12 @@ ix86_expand_prologue (void)
 	      if (crtl->is_leaf && !cfun->calls_alloca)
 		{
 		  if (size > get_probe_interval ())
-		    ix86_emit_probe_stack_range (0, size);
+		    ix86_emit_probe_stack_range (0, size, int_registers_saved);
 		}
 	      else
 		ix86_emit_probe_stack_range (0,
-					     size + get_stack_check_protect ());
+					     size + get_stack_check_protect (),
+					     int_registers_saved);
 	    }
 	  else
 	    {
@@ -13778,10 +13804,13 @@ ix86_expand_prologue (void)
 		  if (size > get_probe_interval ()
 		      && size > get_stack_check_protect ())
 		    ix86_emit_probe_stack_range (get_stack_check_protect (),
-						 size - get_stack_check_protect ());
+						 (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);
 	    }
 	}
     }
--- gcc/testsuite/gcc.target/i386/pr84064.c
+++ 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);
+}
+