Merge bleeding edge into the GC branch up to 7948. The asserts

src/mips/macro-assembler-mips.h

-// Copyright 2010 the V8 project authors. All rights reserved.
+// 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
 //       with the distribution.
@@ skipping 33 matching lines @@
 // but won't touch other registers except in special cases.
 //
 // Per the MIPS ABI, register t9 must be used for indirect function call
 // via 'jalr t9' or 'jr t9' instructions. This is relied upon by gcc when
 // trying to update gp register for position-independent-code. Whenever
 // MIPS generated code calls C code, it must be via t9 register.
 
 // Registers aliases
 // cp is assumed to be a callee saved register.
 const Register roots = s6;  // Roots array pointer.
-const Register cp = s7;     // JavaScript context pointer
-const Register fp = s8_fp;  // Alias fp
-// Register used for condition evaluation.
+const Register cp = s7;     // JavaScript context pointer.
+const Register fp = s8_fp;  // Alias for fp.
+// Registers used for condition evaluation.
 const Register condReg1 = s4;
 const Register condReg2 = s5;
 
 
 // Flags used for the AllocateInNewSpace functions.
 enum AllocationFlags {
   // No special flags.
   NO_ALLOCATION_FLAGS = 0,
   // Return the pointer to the allocated already tagged as a heap object.
   TAG_OBJECT = 1 << 0,
@@ skipping 17 matching lines @@
 
 // Allow programmer to use Branch Delay Slot of Branches, Jumps, Calls.
 enum BranchDelaySlot {
   USE_DELAY_SLOT,
   PROTECT
 };
 
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler: public Assembler {
  public:
-  MacroAssembler(void* buffer, int size);
+  // The isolate parameter can be NULL if the macro assembler should
+  // not use isolate-dependent functionality. In this case, it's the
+  // responsibility of the caller to never invoke such function on the
+  // macro assembler.
+  MacroAssembler(Isolate* isolate, void* buffer, int size);
 
-// Arguments macros
+// Arguments macros.
 #define COND_TYPED_ARGS Condition cond, Register r1, const Operand& r2
 #define COND_ARGS cond, r1, r2
 
-// ** Prototypes
+// Prototypes.
 
-// * Prototypes for functions with no target (eg Ret()).
+// Prototypes for functions with no target (eg Ret()).
 #define DECLARE_NOTARGET_PROTOTYPE(Name) \
   void Name(BranchDelaySlot bd = PROTECT); \
   void Name(COND_TYPED_ARGS, BranchDelaySlot bd = PROTECT); \
   inline void Name(BranchDelaySlot bd, COND_TYPED_ARGS) { \
     Name(COND_ARGS, bd); \
   }
 
-// * Prototypes for functions with a target.
+// Prototypes for functions with a target.
 
 // Cases when relocation may be needed.
 #define DECLARE_RELOC_PROTOTYPE(Name, target_type) \
   void Name(target_type target, \
             RelocInfo::Mode rmode, \
             BranchDelaySlot bd = PROTECT); \
   inline void Name(BranchDelaySlot bd, \
                    target_type target, \
                    RelocInfo::Mode rmode) { \
     Name(target, rmode, bd); \
@@ skipping 17 matching lines @@
   } \
   void Name(target_type target, \
             COND_TYPED_ARGS, \
             BranchDelaySlot bd = PROTECT); \
   inline void Name(BranchDelaySlot bd, \
                    target_type target, \
                    COND_TYPED_ARGS) { \
     Name(target, COND_ARGS, bd); \
   }
 
-// ** Target prototypes.
+// Target prototypes.
 
 #define DECLARE_JUMP_CALL_PROTOTYPES(Name) \
   DECLARE_NORELOC_PROTOTYPE(Name, Register) \
   DECLARE_NORELOC_PROTOTYPE(Name, const Operand&) \
   DECLARE_RELOC_PROTOTYPE(Name, byte*) \
   DECLARE_RELOC_PROTOTYPE(Name, Handle<Code>)
 
 #define DECLARE_BRANCH_PROTOTYPES(Name) \
   DECLARE_NORELOC_PROTOTYPE(Name, Label*) \
   DECLARE_NORELOC_PROTOTYPE(Name, int16_t)
 
 
 DECLARE_JUMP_CALL_PROTOTYPES(Jump)
 DECLARE_JUMP_CALL_PROTOTYPES(Call)
 
 DECLARE_BRANCH_PROTOTYPES(Branch)
 DECLARE_BRANCH_PROTOTYPES(BranchAndLink)
 
 DECLARE_NOTARGET_PROTOTYPE(Ret)
 
 #undef COND_TYPED_ARGS
 #undef COND_ARGS
 #undef DECLARE_NOTARGET_PROTOTYPE
 #undef DECLARE_NORELOC_PROTOTYPE
 #undef DECLARE_RELOC_PROTOTYPE
 #undef DECLARE_JUMP_CALL_PROTOTYPES
 #undef DECLARE_BRANCH_PROTOTYPES
 
+  void CallWithAstId(Handle<Code> code,
+                     RelocInfo::Mode rmode,
+                     unsigned ast_id,
+                     Condition cond = al,
+                     Register r1 = zero_reg,
+                     const Operand& r2 = Operand(zero_reg));
+
+  int CallSize(Register reg);
+  int CallSize(Handle<Code> code, RelocInfo::Mode rmode);
+
   // Emit code to discard a non-negative number of pointer-sized elements
   // from the stack, clobbering only the sp register.
   void Drop(int count,
             Condition cond = cc_always,
             Register reg = no_reg,
             const Operand& op = Operand(no_reg));
 
   void DropAndRet(int drop = 0,
                   Condition cond = cc_always,
                   Register reg = no_reg,
@@ skipping 61 matching lines @@
   // [address] dirty. The object address must be in the first 8K of an
   // allocated page.  All 3 registers are clobbered by the operation,
   // as well as the ip register. RecordWrite updates the write barrier
   // even when storing smis.
   void RecordWrite(Register object,
                    Register address,
                    Register scratch);
 
 
   // ---------------------------------------------------------------------------
-  // Inline caching support
+  // Inline caching support.
 
   // Generate code for checking access rights - used for security checks
   // on access to global objects across environments. The holder register
   // is left untouched, whereas both scratch registers are clobbered.
   void CheckAccessGlobalProxy(Register holder_reg,
                               Register scratch,
                               Label* miss);
 
   inline void MarkCode(NopMarkerTypes type) {
     nop(type);
@@ skipping 23 matching lines @@
     int type =
         (sllzz && FIRST_IC_MARKER <= sa && sa < LAST_CODE_MARKER) ? sa : -1;
     ASSERT((type == -1) ||
            ((FIRST_IC_MARKER <= type) && (type < LAST_CODE_MARKER)));
     return type;
   }
 
 
 
   // ---------------------------------------------------------------------------
-  // Allocation support
+  // Allocation support.
 
   // Allocate an object in new space. The object_size is specified
   // either in bytes or in words if the allocation flag SIZE_IN_WORDS
   // is passed. If the new space is exhausted control continues at the
   // gc_required label. The allocated object is returned in result. If
   // the flag tag_allocated_object is true the result is tagged as as
   // a heap object. All registers are clobbered also when control
   // continues at the gc_required label.
   void AllocateInNewSpace(int object_size,
                           Register result,
@@ skipping 46 matching lines @@
                           Register scratch2,
                           Register heap_number_map,
                           Label* gc_required);
   void AllocateHeapNumberWithValue(Register result,
                                    FPURegister value,
                                    Register scratch1,
                                    Register scratch2,
                                    Label* gc_required);
 
   // ---------------------------------------------------------------------------
-  // Instruction macros
+  // Instruction macros.
 
 #define DEFINE_INSTRUCTION(instr)                                              \
   void instr(Register rd, Register rs, const Operand& rt);                     \
   void instr(Register rd, Register rs, Register rt) {                          \
     instr(rd, rs, Operand(rt));                                                \
   }                                                                            \
   void instr(Register rs, Register rt, int32_t j) {                            \
     instr(rs, rt, Operand(j));                                                 \
   }
 
@@ skipping 11 matching lines @@
   DEFINE_INSTRUCTION(Mul);
   DEFINE_INSTRUCTION2(Mult);
   DEFINE_INSTRUCTION2(Multu);
   DEFINE_INSTRUCTION2(Div);
   DEFINE_INSTRUCTION2(Divu);
 
   DEFINE_INSTRUCTION(And);
   DEFINE_INSTRUCTION(Or);
   DEFINE_INSTRUCTION(Xor);
   DEFINE_INSTRUCTION(Nor);
+  DEFINE_INSTRUCTION2(Neg);
 
   DEFINE_INSTRUCTION(Slt);
   DEFINE_INSTRUCTION(Sltu);
 
   // MIPS32 R2 instruction macro.
   DEFINE_INSTRUCTION(Ror);
 
 #undef DEFINE_INSTRUCTION
 #undef DEFINE_INSTRUCTION2
 
 
-  //------------Pseudo-instructions-------------
+  // ---------------------------------------------------------------------------
+  // Pseudo-instructions.
 
   void mov(Register rd, Register rt) { or_(rd, rt, zero_reg); }
 
-
-  // load int32 in the rd register
+  // Load int32 in the rd register.
   void li(Register rd, Operand j, bool gen2instr = false);
   inline void li(Register rd, int32_t j, bool gen2instr = false) {
     li(rd, Operand(j), gen2instr);
   }
   inline void li(Register dst, Handle<Object> value, bool gen2instr = false) {
     li(dst, Operand(value), gen2instr);
   }
 
-  // Exception-generating instructions and debugging support
+  // Exception-generating instructions and debugging support.
   void stop(const char* msg);
 
-
   // Push multiple registers on the stack.
   // Registers are saved in numerical order, with higher numbered registers
-  // saved in higher memory addresses
+  // saved in higher memory addresses.
   void MultiPush(RegList regs);
   void MultiPushReversed(RegList regs);
 
-  void Push(Register src) {
+  // Lower case push() for compatibility with arch-independent code.
+  void push(Register src) {
     Addu(sp, sp, Operand(-kPointerSize));
     sw(src, MemOperand(sp, 0));
   }
 
-  // Push two registers.  Pushes leftmost register first (to highest address).
-  void Push(Register src1, Register src2, Condition cond = al) {
-    ASSERT(cond == al);  // Do not support conditional versions yet.
+  // Push two registers. Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2) {
     Subu(sp, sp, Operand(2 * kPointerSize));
     sw(src1, MemOperand(sp, 1 * kPointerSize));
     sw(src2, MemOperand(sp, 0 * kPointerSize));
   }
 
-  // Push three registers.  Pushes leftmost register first (to highest address).
-  void Push(Register src1, Register src2, Register src3, Condition cond = al) {
-    ASSERT(cond == al);  // Do not support conditional versions yet.
-    Addu(sp, sp, Operand(3 * -kPointerSize));
+  // Push three registers. Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2, Register src3) {
+    Subu(sp, sp, Operand(3 * kPointerSize));
     sw(src1, MemOperand(sp, 2 * kPointerSize));
     sw(src2, MemOperand(sp, 1 * kPointerSize));
     sw(src3, MemOperand(sp, 0 * kPointerSize));
   }
 
-  // Push four registers.  Pushes leftmost register first (to highest address).
-  void Push(Register src1, Register src2,
-            Register src3, Register src4, Condition cond = al) {
-    ASSERT(cond == al);  // Do not support conditional versions yet.
-    Addu(sp, sp, Operand(4 * -kPointerSize));
+  // Push four registers. Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2, Register src3, Register src4) {
+    Subu(sp, sp, Operand(4 * kPointerSize));
     sw(src1, MemOperand(sp, 3 * kPointerSize));
     sw(src2, MemOperand(sp, 2 * kPointerSize));
     sw(src3, MemOperand(sp, 1 * kPointerSize));
     sw(src4, MemOperand(sp, 0 * kPointerSize));
   }
 
-  inline void push(Register src) { Push(src); }
-  inline void pop(Register src) { Pop(src); }
-
   void Push(Register src, Condition cond, Register tst1, Register tst2) {
-    // Since we don't have conditionnal execution we use a Branch.
+    // Since we don't have conditional execution we use a Branch.
     Branch(3, cond, tst1, Operand(tst2));
-    Addu(sp, sp, Operand(-kPointerSize));
+    Subu(sp, sp, Operand(kPointerSize));
     sw(src, MemOperand(sp, 0));
   }
 
-
   // Pops multiple values from the stack and load them in the
   // registers specified in regs. Pop order is the opposite as in MultiPush.
   void MultiPop(RegList regs);
   void MultiPopReversed(RegList regs);
-  void Pop(Register dst) {
+
+  // Lower case pop() for compatibility with arch-independent code.
+  void pop(Register dst) {
     lw(dst, MemOperand(sp, 0));
     Addu(sp, sp, Operand(kPointerSize));
   }
+
+  // Pop two registers. Pops rightmost register first (from lower address).
+  void Pop(Register src1, Register src2) {
+    ASSERT(!src1.is(src2));
+    lw(src2, MemOperand(sp, 0 * kPointerSize));
+    lw(src1, MemOperand(sp, 1 * kPointerSize));
+    Addu(sp, sp, 2 * kPointerSize);
+  }
+
   void Pop(uint32_t count = 1) {
     Addu(sp, sp, Operand(count * kPointerSize));
   }
 
   // ---------------------------------------------------------------------------
   // These functions are only used by crankshaft, so they are currently
   // unimplemented.
 
   // Push and pop the registers that can hold pointers, as defined by the
   // RegList constant kSafepointSavedRegisters.
@@ skipping 36 matching lines @@
   // dest. If the HeapNumber does not fit into a 32bits signed integer branch
   // to not_int32 label. If FPU is available double_scratch is used but not
   // scratch2.
   void ConvertToInt32(Register source,
                       Register dest,
                       Register scratch,
                       Register scratch2,
                       FPURegister double_scratch,
                       Label *not_int32);
 
+  // Helper for EmitECMATruncate.
+  // This will truncate a floating-point value outside of the singed 32bit
+  // integer range to a 32bit signed integer.
+  // Expects the double value loaded in input_high and input_low.
+  // Exits with the answer in 'result'.
+  // Note that this code does not work for values in the 32bit range!
+  void EmitOutOfInt32RangeTruncate(Register result,
+                                   Register input_high,
+                                   Register input_low,
+                                   Register scratch);
+
   // -------------------------------------------------------------------------
-  // Activation frames
+  // Activation frames.
 
   void EnterInternalFrame() { EnterFrame(StackFrame::INTERNAL); }
   void LeaveInternalFrame() { LeaveFrame(StackFrame::INTERNAL); }
 
   void EnterConstructFrame() { EnterFrame(StackFrame::CONSTRUCT); }
   void LeaveConstructFrame() { LeaveFrame(StackFrame::CONSTRUCT); }
 
   // Enter exit frame.
-  // Expects the number of arguments in register a0 and
-  // the builtin function to call in register a1.
-  // On output hold_argc, hold_function, and hold_argv are setup.
-  void EnterExitFrame(Register hold_argc,
-                      Register hold_argv,
-                      Register hold_function,
-                      bool save_doubles);
+  // argc - argument count to be dropped by LeaveExitFrame.
+  // save_doubles - saves FPU registers on stack, currently disabled.
+  // stack_space - extra stack space.
+  void EnterExitFrame(bool save_doubles,
+                      int stack_space = 0);
 
-  // Leave the current exit frame. Expects the return value in v0.
-  void LeaveExitFrame(bool save_doubles);
-
-  // Align the stack by optionally pushing a Smi zero.
-  void AlignStack(int offset);    // TODO(mips) : remove this function.
+  // Leave the current exit frame.
+  void LeaveExitFrame(bool save_doubles, Register arg_count);
 
   // Get the actual activation frame alignment for target environment.
   static int ActivationFrameAlignment();
 
+  // Make sure the stack is aligned. Only emits code in debug mode.
+  void AssertStackIsAligned();
+
   void LoadContext(Register dst, int context_chain_length);
 
   void LoadGlobalFunction(int index, Register function);
 
   // Load the initial map from the global function. The registers
   // function and map can be the same, function is then overwritten.
   void LoadGlobalFunctionInitialMap(Register function,
                                     Register map,
                                     Register scratch);
 
   // -------------------------------------------------------------------------
-  // JavaScript invokes
+  // JavaScript invokes.
 
   // Invoke the JavaScript function code by either calling or jumping.
   void InvokeCode(Register code,
                   const ParameterCount& expected,
                   const ParameterCount& actual,
                   InvokeFlag flag,
                   const CallWrapper& call_wrapper = NullCallWrapper());
 
   void InvokeCode(Handle<Code> code,
                   const ParameterCount& expected,
@@ skipping 21 matching lines @@
   void IsInstanceJSObjectType(Register map,
                               Register scratch,
                               Label* fail);
 
   void IsObjectJSStringType(Register object,
                             Register scratch,
                             Label* fail);
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // -------------------------------------------------------------------------
-  // Debugger Support
+  // Debugger Support.
 
   void DebugBreak();
 #endif
 
 
   // -------------------------------------------------------------------------
-  // Exception handling
+  // Exception handling.
 
   // Push a new try handler and link into try handler chain.
   // The return address must be passed in register ra.
   // Clobber t0, t1, t2.
   void PushTryHandler(CodeLocation try_location, HandlerType type);
 
   // Unlink the stack handler on top of the stack from the try handler chain.
   // Must preserve the result register.
   void PopTryHandler();
 
+  // Passes thrown value (in v0) to the handler of top of the try handler chain.
+  void Throw(Register value);
+
+  // Propagates an uncatchable exception to the top of the current JS stack's
+  // handler chain.
+  void ThrowUncatchable(UncatchableExceptionType type, Register value);
+
   // Copies a fixed number of fields of heap objects from src to dst.
   void CopyFields(Register dst, Register src, RegList temps, int field_count);
 
+  // Copies a number of bytes from src to dst. All registers are clobbered. On
+  // exit src and dst will point to the place just after where the last byte was
+  // read or written and length will be zero.
+  void CopyBytes(Register src,
+                 Register dst,
+                 Register length,
+                 Register scratch);
+
   // -------------------------------------------------------------------------
   // Support functions.
 
   // Try to get function prototype of a function and puts the value in
   // the result register. Checks that the function really is a
   // function and jumps to the miss label if the fast checks fail. The
   // function register will be untouched; the other registers may be
   // clobbered.
   void TryGetFunctionPrototype(Register function,
                                Register result,
                                Register scratch,
                                Label* miss);
 
   void GetObjectType(Register function,
                      Register map,
                      Register type_reg);
 
   // Check if the map of an object is equal to a specified map (either
   // given directly or as an index into the root list) and branch to
   // label if not. Skip the smi check if not required (object is known
-  // to be a heap object)
+  // to be a heap object).
   void CheckMap(Register obj,
                 Register scratch,
                 Handle<Map> map,
                 Label* fail,
                 bool is_heap_object);
 
   void CheckMap(Register obj,
                 Register scratch,
                 Heap::RootListIndex index,
                 Label* fail,
                 bool is_heap_object);
 
   // Generates code for reporting that an illegal operation has
   // occurred.
   void IllegalOperation(int num_arguments);
 
   // Picks out an array index from the hash field.
   // Register use:
   //   hash - holds the index's hash. Clobbered.
   //   index - holds the overwritten index on exit.
   void IndexFromHash(Register hash, Register index);
 
+  // Get the number of least significant bits from a register.
+  void GetLeastBitsFromSmi(Register dst, Register src, int num_least_bits);
+  void GetLeastBitsFromInt32(Register dst, Register src, int mun_least_bits);
+
   // Load the value of a number object into a FPU double register. If the
   // object is not a number a jump to the label not_number is performed
   // and the FPU double register is unchanged.
   void ObjectToDoubleFPURegister(
       Register object,
       FPURegister value,
       Register scratch1,
       Register scratch2,
       Register heap_number_map,
       Label* not_number,
       ObjectToDoubleFlags flags = NO_OBJECT_TO_DOUBLE_FLAGS);
 
   // Load the value of a smi object into a FPU double register. The register
   // scratch1 can be the same register as smi in which case smi will hold the
   // untagged value afterwards.
   void SmiToDoubleFPURegister(Register smi,
                               FPURegister value,
                               Register scratch1);
 
   // -------------------------------------------------------------------------
-  // Runtime calls
+  // Overflow handling functions.
+  // Usage: first call the appropriate arithmetic function, then call one of the
+  // jump functions with the overflow_dst register as the second parameter.
+
+  void AdduAndCheckForOverflow(Register dst,
+                               Register left,
+                               Register right,
+                               Register overflow_dst,
+                               Register scratch = at);
+
+  void SubuAndCheckForOverflow(Register dst,
+                               Register left,
+                               Register right,
+                               Register overflow_dst,
+                               Register scratch = at);
+
+  void BranchOnOverflow(Label* label,
+                        Register overflow_check,
+                        BranchDelaySlot bd = PROTECT) {
+    Branch(label, lt, overflow_check, Operand(zero_reg), bd);
+  }
+
+  void BranchOnNoOverflow(Label* label,
+                          Register overflow_check,
+                          BranchDelaySlot bd = PROTECT) {
+    Branch(label, ge, overflow_check, Operand(zero_reg), bd);
+  }
+
+  void RetOnOverflow(Register overflow_check, BranchDelaySlot bd = PROTECT) {
+    Ret(lt, overflow_check, Operand(zero_reg), bd);
+  }
+
+  void RetOnNoOverflow(Register overflow_check, BranchDelaySlot bd = PROTECT) {
+    Ret(ge, overflow_check, Operand(zero_reg), bd);
+  }
+
+  // -------------------------------------------------------------------------
+  // Runtime calls.
 
   // Call a code stub.
   void CallStub(CodeStub* stub, Condition cond = cc_always,
                 Register r1 = zero_reg, const Operand& r2 = Operand(zero_reg));
 
+  // Call a code stub and return the code object called.  Try to generate
+  // the code if necessary.  Do not perform a GC but instead return a retry
+  // after GC failure.
+  MUST_USE_RESULT MaybeObject* TryCallStub(CodeStub* stub,
+                                           Condition cond = cc_always,
+                                           Register r1 = zero_reg,
+                                           const Operand& r2 =
+                                               Operand(zero_reg));
+
   // Tail call a code stub (jump).
   void TailCallStub(CodeStub* stub);
 
+  // Tail call a code stub (jump) and return the code object called.  Try to
+  // generate the code if necessary.  Do not perform a GC but instead return
+  // a retry after GC failure.
+  MUST_USE_RESULT MaybeObject* TryTailCallStub(CodeStub* stub,
+                                               Condition cond = cc_always,
+                                               Register r1 = zero_reg,
+                                               const Operand& r2 =
+                                                   Operand(zero_reg));
+
   void CallJSExitStub(CodeStub* stub);
 
   // Call a runtime routine.
   void CallRuntime(const Runtime::Function* f, int num_arguments);
   void CallRuntimeSaveDoubles(Runtime::FunctionId id);
 
   // Convenience function: Same as above, but takes the fid instead.
   void CallRuntime(Runtime::FunctionId fid, int num_arguments);
 
   // Convenience function: call an external reference.
   void CallExternalReference(const ExternalReference& ext,
                              int num_arguments);
 
   // Tail call of a runtime routine (jump).
   // Like JumpToExternalReference, but also takes care of passing the number
   // of parameters.
   void TailCallExternalReference(const ExternalReference& ext,
                                  int num_arguments,
                                  int result_size);
 
+  // Tail call of a runtime routine (jump). Try to generate the code if
+  // necessary. Do not perform a GC but instead return a retry after GC
+  // failure.
+  MUST_USE_RESULT MaybeObject* TryTailCallExternalReference(
+      const ExternalReference& ext, int num_arguments, int result_size);
+
   // Convenience function: tail call a runtime routine (jump).
   void TailCallRuntime(Runtime::FunctionId fid,
                        int num_arguments,
                        int result_size);
 
   // Before calling a C-function from generated code, align arguments on stack
   // and add space for the four mips argument slots.
   // After aligning the frame, non-register arguments must be stored on the
   // stack, after the argument-slots using helper: CFunctionArgumentOperand().
   // The argument count assumes all arguments are word sized.
   // Some compilers/platforms require the stack to be aligned when calling
   // C++ code.
   // Needs a scratch register to do some arithmetic. This register will be
   // trashed.
   void PrepareCallCFunction(int num_arguments, Register scratch);
 
   // Arguments 1-4 are placed in registers a0 thru a3 respectively.
   // Arguments 5..n are stored to stack using following:
   //  sw(t0, CFunctionArgumentOperand(5));
 
   // Calls a C function and cleans up the space for arguments allocated
   // by PrepareCallCFunction. The called function is not allowed to trigger a
   // garbage collection, since that might move the code and invalidate the
   // return address (unless this is somehow accounted for by the called
   // function).
   void CallCFunction(ExternalReference function, int num_arguments);
   void CallCFunction(Register function, Register scratch, int num_arguments);
+  void GetCFunctionDoubleResult(const DoubleRegister dst);
+
+  // Calls an API function. Allocates HandleScope, extracts returned value
+  // from handle and propagates exceptions. Restores context.
+  MaybeObject* TryCallApiFunctionAndReturn(ExternalReference function,
+                                           int stack_space);
 
   // Jump to the builtin routine.
   void JumpToExternalReference(const ExternalReference& builtin);
 
+  MaybeObject* TryJumpToExternalReference(const ExternalReference& ext);
+
   // Invoke specified builtin JavaScript function. Adds an entry to
   // the unresolved list if the name does not resolve.
   void InvokeBuiltin(Builtins::JavaScript id,
                      InvokeFlag flag,
                      const CallWrapper& call_wrapper = NullCallWrapper());
 
   // Store the code object for the given builtin in the target register and
   // setup the function in a1.
   void GetBuiltinEntry(Register target, Builtins::JavaScript id);
 
   // Store the function for the given builtin in the target register.
   void GetBuiltinFunction(Register target, Builtins::JavaScript id);
 
   struct Unresolved {
     int pc;
-    uint32_t flags;  // see Bootstrapper::FixupFlags decoders/encoders.
+    uint32_t flags;  // See Bootstrapper::FixupFlags decoders/encoders.
     const char* name;
   };
 
-  Handle<Object> CodeObject() { return code_object_; }
+  Handle<Object> CodeObject() {
+    ASSERT(!code_object_.is_null());
+    return code_object_;
+  }
 
   // -------------------------------------------------------------------------
-  // StatsCounter support
+  // StatsCounter support.
 
   void SetCounter(StatsCounter* counter, int value,
                   Register scratch1, Register scratch2);
   void IncrementCounter(StatsCounter* counter, int value,
                         Register scratch1, Register scratch2);
   void DecrementCounter(StatsCounter* counter, int value,
                         Register scratch1, Register scratch2);
 
 
   // -------------------------------------------------------------------------
-  // Debugging
+  // Debugging.
 
   // Calls Abort(msg) if the condition cc is not satisfied.
   // Use --debug_code to enable.
   void Assert(Condition cc, const char* msg, Register rs, Operand rt);
   void AssertRegisterIsRoot(Register reg, Heap::RootListIndex index);
   void AssertFastElements(Register elements);
 
   // Like Assert(), but always enabled.
   void Check(Condition cc, const char* msg, Register rs, Operand rt);
 
   // Print a message to stdout and abort execution.
   void Abort(const char* msg);
 
   // Verify restrictions about code generated in stubs.
   void set_generating_stub(bool value) { generating_stub_ = value; }
   bool generating_stub() { return generating_stub_; }
   void set_allow_stub_calls(bool value) { allow_stub_calls_ = value; }
   bool allow_stub_calls() { return allow_stub_calls_; }
 
   // ---------------------------------------------------------------------------
-  // Number utilities
+  // Number utilities.
 
   // Check whether the value of reg is a power of two and not zero. If not
   // control continues at the label not_power_of_two. If reg is a power of two
   // the register scratch contains the value of (reg - 1) when control falls
   // through.
   void JumpIfNotPowerOfTwoOrZero(Register reg,
                                  Register scratch,
                                  Label* not_power_of_two_or_zero);
 
   // -------------------------------------------------------------------------
-  // Smi utilities
+  // Smi utilities.
 
   // Try to convert int32 to smi. If the value is to large, preserve
   // the original value and jump to not_a_smi. Destroys scratch and
   // sets flags.
   // This is only used by crankshaft atm so it is unimplemented on MIPS.
   void TrySmiTag(Register reg, Label* not_a_smi, Register scratch) {
     UNIMPLEMENTED_MIPS();
   }
 
   void SmiTag(Register reg) {
@@ skipping 30 matching lines @@
 
   // Jump if either of the registers contain a non-smi.
   void JumpIfNotBothSmi(Register reg1, Register reg2, Label* on_not_both_smi);
   // Jump if either of the registers contain a smi.
   void JumpIfEitherSmi(Register reg1, Register reg2, Label* on_either_smi);
 
   // Abort execution if argument is a smi. Used in debug code.
   void AbortIfSmi(Register object);
   void AbortIfNotSmi(Register object);
 
+  // Abort execution if argument is a string. Used in debug code.
+  void AbortIfNotString(Register object);
+
   // Abort execution if argument is not the root value with the given index.
   void AbortIfNotRootValue(Register src,
                            Heap::RootListIndex root_value_index,
                            const char* message);
 
   // ---------------------------------------------------------------------------
-  // HeapNumber utilities
+  // HeapNumber utilities.
 
   void JumpIfNotHeapNumber(Register object,
                            Register heap_number_map,
                            Register scratch,
                            Label* on_not_heap_number);
 
   // -------------------------------------------------------------------------
-  // String utilities
+  // String utilities.
 
   // Checks if both instance types are sequential ASCII strings and jumps to
   // label if either is not.
   void JumpIfBothInstanceTypesAreNotSequentialAscii(
       Register first_object_instance_type,
       Register second_object_instance_type,
       Register scratch1,
       Register scratch2,
       Label* failure);
 
@@ skipping 60 matching lines @@
                            Register scratch2);
 
 
   bool generating_stub_;
   bool allow_stub_calls_;
   // This handle will be patched with the code object on installation.
   Handle<Object> code_object_;
 };
 
 
-#ifdef ENABLE_DEBUGGER_SUPPORT
 // The code patcher is used to patch (typically) small parts of code e.g. for
 // debugging and other types of instrumentation. When using the code patcher
 // the exact number of bytes specified must be emitted. It is not legal to emit
 // relocation information. If any of these constraints are violated it causes
 // an assertion to fail.
 class CodePatcher {
  public:
   CodePatcher(byte* address, int instructions);
   virtual ~CodePatcher();
 
   // Macro assembler to emit code.
   MacroAssembler* masm() { return &masm_; }
 
   // Emit an instruction directly.
-  void Emit(Instr x);
+  void Emit(Instr instr);
 
   // Emit an address directly.
   void Emit(Address addr);
 
+  // Change the condition part of an instruction leaving the rest of the current
+  // instruction unchanged.
+  void ChangeBranchCondition(Condition cond);
+
  private:
   byte* address_;  // The address of the code being patched.
   int instructions_;  // Number of instructions of the expected patch size.
   int size_;  // Number of bytes of the expected patch size.
   MacroAssembler masm_;  // Macro assembler used to generate the code.
 };
-#endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 // -----------------------------------------------------------------------------
 // Static helper functions.
 
 static MemOperand ContextOperand(Register context, int index) {
   return MemOperand(context, Context::SlotOffset(index));
 }
 
 
 static inline MemOperand GlobalObjectOperand()  {
   return ContextOperand(cp, Context::GLOBAL_INDEX);
 }
 
 
 // Generate a MemOperand for loading a field from an object.
 static inline MemOperand FieldMemOperand(Register object, int offset) {
   return MemOperand(object, offset - kHeapObjectTag);
 }
 
 
+// Generate a MemOperand for storing arguments 5..N on the stack
+// when calling CallCFunction().
+static inline MemOperand CFunctionArgumentOperand(int index) {
+  ASSERT(index > StandardFrameConstants::kCArgSlotCount);
+  // Argument 5 takes the slot just past the four Arg-slots.
+  int offset =
+      (index - 5) * kPointerSize + StandardFrameConstants::kCArgsSlotsSize;
+  return MemOperand(sp, offset);
+}
+
 
 #ifdef GENERATED_CODE_COVERAGE
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_