Avoid trying to decode the raw inline constant which is part of the aged code prologue.

BUG=v8:3007
LOG=N
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/88303003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18097 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/constants-arm.h

@@ -50,6 +50,9 @@ inline int DecodeConstantPoolLength(int instr) {
   return ((instr >> 4) & 0xfff0) | (instr & 0xf);
 }
 
+// Used in code age prologue - ldr(pc, MemOperand(pc, -4))
+const int kCodeAgeJumpInstruction = 0xe51ff004;
+
 // Number of registers in normal ARM mode.
 const int kNumRegisters = 16;
 

src/arm/disasm-arm.cc

@@ -1679,6 +1679,14 @@ int Decoder::InstructionDecode(byte* instr_ptr) {
                                     "constant pool begin (length %d)",
                                     DecodeConstantPoolLength(instruction_bits));
     return Instruction::kInstrSize;
+  } else if (instruction_bits == kCodeAgeJumpInstruction) {
+    // The code age prologue has a constant immediatly following the jump
+    // instruction.
+    Instruction* target = Instruction::At(instr_ptr + Instruction::kInstrSize);
+    DecodeType2(instr);
+    OS::SNPrintF(out_buffer_ + out_buffer_pos_,
+                 " (0x%08x)", target->InstructionBits());
+    return 2 * Instruction::kInstrSize;
   }
   switch (instr->TypeValue()) {
     case 0: