Change constant pool marker to be the unconditional, permanently undefined instruction.

src/arm/constants-arm.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 66 matching lines @@
 
 // Using blx may yield better code, so use it when required or when available
 #if defined(USE_THUMB_INTERWORK) || defined(CAN_USE_ARMV5_INSTRUCTIONS)
 #define USE_BLX 1
 #endif
 
 namespace v8 {
 namespace internal {
 
 // Constant pool marker.
-const int kConstantPoolMarkerMask = 0xffe00000;
-const int kConstantPoolMarker = 0x0c000000;
-const int kConstantPoolLengthMask = 0x001ffff;
+// Use UDF, the permanently undefined instruction.
+const int kConstantPoolMarkerMask = 0xfff000f0;
+const int kConstantPoolMarker = 0xe7f000f0;
+const int kConstantPoolLengthMaxMask = 0xffff;
+inline int EncodeConstantPoolLength(int length) {
+  ASSERT((length & kConstantPoolLengthMaxMask) == length);
+  return ((length & 0xfff0) << 4) | (length & 0xf);
+}
+inline int DecodeConstantPoolLength(int instr) {
+  ASSERT((instr & kConstantPoolMarkerMask) == kConstantPoolMarker);
+  return ((instr >> 4) & 0xfff0) | (instr & 0xf);
+}
 
 // Number of registers in normal ARM mode.
 const int kNumRegisters = 16;
 
 // VFP support.
 const int kNumVFPSingleRegisters = 32;
 const int kNumVFPDoubleRegisters = 16;
 const int kNumVFPRegisters = kNumVFPSingleRegisters + kNumVFPDoubleRegisters;
 
 // PC is register 15.
@@ skipping 665 matching lines @@
   static int Number(const char* name, bool* is_double);
 
  private:
   static const char* names_[kNumVFPRegisters];
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_CONSTANTS_ARM_H_