A64: Fix sampling of fp register for CPU profile and bailout if sp or fp is zero.

src/a64/simulator-a64.h

Index: src/a64/simulator-a64.h
diff --git a/src/a64/simulator-a64.h b/src/a64/simulator-a64.h
index af4b9a59257c3a25127467f757dc1b146b3faf38..e20ce685b5c6bd742003c2e4600138ec875070f8 100644
--- a/src/a64/simulator-a64.h
+++ b/src/a64/simulator-a64.h
@@ -440,6 +440,7 @@ class Simulator : public DecoderVisitor {
 
   inline int64_t sp() { return xreg(31, Reg31IsStackPointer); }
   inline int64_t jssp() { return xreg(kJSSPCode, Reg31IsStackPointer); }
+  inline int64_t fp() { return xreg(29, Reg31IsStackPointer); }

[jbramley, 2014/01/27 10:40:21]

We have a kFramePointerRegCode.

[ulan, 2014/01/27 10:55:06]

Done.

   inline Instruction* lr() { return reg<Instruction*>(kLinkRegCode); }
 
   // Return 'size' bits of the value of a floating-point register, as the