[PATCH][RFA/RFC] Stack clash mitigation patch 03/08 V2

[Jeff Law]

I don't think this patch changed in any significant way since V1.
--

One of the painful aspects of all this code is the amount of target
dependent bits that have to be written and tested.

I didn't want to be scanning assembly code or RTL for prologues.  Each
target would have to have its own scanner which was too painful to
contemplate.

So instead I settled on having a routine that the target dependent
prologue expanders could call to dump information about what they were
doing.

This greatly simplifies the testing side of things by having a standard
way to dump decisions.  When combined with the dejagnu routines from
patch #1 which describe key attributes of the target's prologue
generation I can write tests in a fairly generic way.

This will be used by every target dependent prologue expander in this
series.

OK for the trunk?

commit ff99b9cb21a195fb2b2c0e4d580db2b1e806ec97
Author: Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Date:   Thu Apr 14 10:52:45 2016 +0100

    [AArch64] From Andrew Pinski: Work around PR target/64971

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index da85a7f..a9e811e 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -855,6 +855,13 @@ (define_expand "sibcall"
 	   || aarch64_is_noplt_call_p (callee)))
       XEXP (operands[0], 0) = force_reg (Pmode, callee);
 
+    /* FIXME: This is a band-aid.  Need to analyze why expand_expr_addr_expr
+       is generating an SImode symbol reference.  See PR 64971.  */
+    if (TARGET_ILP32
+	&& GET_CODE (XEXP (operands[0], 0)) == SYMBOL_REF
+	&& GET_MODE (XEXP (operands[0], 0)) == SImode)
+      XEXP (operands[0], 0) = convert_memory_address (Pmode,
+						      XEXP (operands[0], 0));
     if (operands[2] == NULL_RTX)
       operands[2] = const0_rtx;
 
@@ -886,6 +893,14 @@ (define_expand "sibcall_value"
 	   || aarch64_is_noplt_call_p (callee)))
       XEXP (operands[1], 0) = force_reg (Pmode, callee);
 
+    /* FIXME: This is a band-aid.  Need to analyze why expand_expr_addr_expr
+       is generating an SImode symbol reference.  See PR 64971.  */
+    if (TARGET_ILP32
+	&& GET_CODE (XEXP (operands[1], 0)) == SYMBOL_REF
+	&& GET_MODE (XEXP (operands[1], 0)) == SImode)
+      XEXP (operands[1], 0) = convert_memory_address (Pmode,
+						      XEXP (operands[1], 0));
+
     if (operands[3] == NULL_RTX)
       operands[3] = const0_rtx;
 
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr37433-1.c b/gcc/testsuite/gcc.c-torture/compile/pr37433-1.c
new file mode 100644
index 0000000..322c167
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr37433-1.c
@@ -0,0 +1,11 @@
+void regex_subst(void)
+{
+  const void *subst = "";
+  (*(void (*)(int))subst) (0);
+}
+
+void foobar (void)
+{
+  int x;
+  (*(void (*)(void))&x) ();
+}