Track prologue offset of Code and use for more precise return addresses

runtime/vm/instructions_ia32.h

Index: runtime/vm/instructions_ia32.h
diff --git a/runtime/vm/instructions_ia32.h b/runtime/vm/instructions_ia32.h
index 7f9f1885b8c4f5825a091c5996aa93c4c28ef03d..683668d0fd47e6da335ae5cff34dd815c5e50908 100644
--- a/runtime/vm/instructions_ia32.h
+++ b/runtime/vm/instructions_ia32.h
@@ -106,6 +106,30 @@ class ReturnPattern : public InstructionPattern {
   static const int kLengthInBytes = 1;
 };
 
+

[srdjan, 2015/05/21 16:06:33]

Please add tests for these two new patterns, best use Assembler::EnterFrame
since the pattern is tied to this. Also for X64. 

Maybe instead of tests add an assert in EnterFrame, that the pattern matches
what EnterFrame is emitting.

[Cutch, 2015/05/22 01:11:14]

Done.

+class ProloguePattern : public InstructionPattern {
+ public:
+  explicit ProloguePattern(uword pc) : InstructionPattern(pc) {}
+
+  virtual const int* pattern() const;

[srdjan, 2015/05/21 16:06:33]

I wonder why we are using int instead of intptr_t here. It is not the objective
of this CL to do that cleanup.

[Cutch, 2015/05/22 01:11:14]

Acknowledged.

+  virtual int pattern_length_in_bytes() const { return kLengthInBytes; }
+
+ private:
+  static const int kLengthInBytes = 3;
+};
+
+
+class SetFramePointerPattern : public InstructionPattern {
+ public:
+  explicit SetFramePointerPattern(uword pc) : InstructionPattern(pc) {}
+
+  virtual const int* pattern() const;
+  virtual int pattern_length_in_bytes() const { return kLengthInBytes; }
+
+ private:
+  static const int kLengthInBytes = 2;
+};
+
 }  // namespace dart
 
 #endif  // VM_INSTRUCTIONS_IA32_H_