Fix the full compiler on ARM to always generate the same code

src/arm/assembler-arm.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 406 matching lines @@
   explicit Operand(Register rm, ShiftOp shift_op, Register rs);
 
   // Return true if this is a register operand.
   INLINE(bool is_reg() const);
 
   // Return true if this operand fits in one instruction so that no
   // 2-instruction solution with a load into the ip register is necessary. If
   // the instruction this operand is used for is a MOV or MVN instruction the
   // actual instruction to use is required for this calculation. For other
   // instructions instr is ignored.
-  bool is_single_instruction(Instr instr = 0) const;
-  bool must_use_constant_pool() const;
+  bool is_single_instruction(const Assembler* assembler, Instr instr = 0) const;
+  bool must_use_constant_pool(const Assembler* assembler) const;
 
   inline int32_t immediate() const {
     ASSERT(!rm_.is_valid());
     return imm32_;
   }
 
   Register rm() const { return rm_; }
   Register rs() const { return rs_; }
   ShiftOp shift_op() const { return shift_op_; }
 
@@ skipping 202 matching lines @@
   // If the provided buffer is not NULL, the assembler uses the provided buffer
   // for code generation and assumes its size to be buffer_size. If the buffer
   // is too small, a fatal error occurs. No deallocation of the buffer is done
   // upon destruction of the assembler.
   Assembler(Isolate* isolate, void* buffer, int buffer_size);
   ~Assembler();
 
   // Overrides the default provided by FLAG_debug_code.
   void set_emit_debug_code(bool value) { emit_debug_code_ = value; }
 
-  // Dummy for cross platform compatibility.
-  void set_predictable_code_size(bool value) { }
+  // Avoids using instructions that vary in size in unpredictable ways between
+  // the snapshot and the running VM.  This is needed by the full compiler so
+  // that it can recompile code with debug support and fix the PC.
+  void set_predictable_code_size(bool value) { predictable_code_size_ = value; }
 
   // GetCode emits any pending (non-emitted) code and fills the descriptor
   // desc. GetCode() is idempotent; it returns the same result if no other
   // Assembler functions are invoked in between GetCode() calls.
   void GetCode(CodeDesc* desc);
 
   // Label operations & relative jumps (PPUM Appendix D)
   //
   // Takes a branch opcode (cc) and a label (L) and generates
   // either a backward branch or a forward branch and links it
@@ skipping 500 matching lines @@
     ldr(dst, MemOperand(sp, 4, PostIndex), cond);
   }
 
   void pop() {
     add(sp, sp, Operand(kPointerSize));
   }
 
   // Jump unconditionally to given label.
   void jmp(Label* L) { b(L, al); }
 
+  bool predictable_code_size() const { return predictable_code_size_; }
+
   // Check the code size generated from label to here.
   int SizeOfCodeGeneratedSince(Label* label) {
     return pc_offset() - label->pos();
   }
 
   // Check the number of instructions generated from label to here.
   int InstructionsGeneratedSince(Label* label) {
     return SizeOfCodeGeneratedSince(label) / kInstrSize;
   }
 
@@ skipping 260 matching lines @@
 
   // Record reloc info for current pc_
   void RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data = 0);
 
   friend class RegExpMacroAssemblerARM;
   friend class RelocInfo;
   friend class CodePatcher;
   friend class BlockConstPoolScope;
 
   PositionsRecorder positions_recorder_;
+
   bool emit_debug_code_;
+  bool predictable_code_size_;
+
   friend class PositionsRecorder;
   friend class EnsureSpace;
 };
 
 
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBuffer();
   }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_ASSEMBLER_ARM_H_