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      1 // Copyright 2006-2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #include "v8.h"
     29 
     30 #include "codegen-inl.h"
     31 #include "debug.h"
     32 #include "runtime.h"
     33 
     34 namespace v8 {
     35 namespace internal {
     36 
     37 
     38 #define __ ACCESS_MASM(masm)
     39 
     40 
     41 void Builtins::Generate_Adaptor(MacroAssembler* masm,
     42                                 CFunctionId id,
     43                                 BuiltinExtraArguments extra_args) {
     44   // ----------- S t a t e -------------
     45   //  -- r0                 : number of arguments excluding receiver
     46   //  -- r1                 : called function (only guaranteed when
     47   //                          extra_args requires it)
     48   //  -- cp                 : context
     49   //  -- sp[0]              : last argument
     50   //  -- ...
     51   //  -- sp[4 * (argc - 1)] : first argument (argc == r0)
     52   //  -- sp[4 * argc]       : receiver
     53   // -----------------------------------
     54 
     55   // Insert extra arguments.
     56   int num_extra_args = 0;
     57   if (extra_args == NEEDS_CALLED_FUNCTION) {
     58     num_extra_args = 1;
     59     __ push(r1);
     60   } else {
     61     ASSERT(extra_args == NO_EXTRA_ARGUMENTS);
     62   }
     63 
     64   // JumpToRuntime expects r0 to contain the number of arguments
     65   // including the receiver and the extra arguments.
     66   __ add(r0, r0, Operand(num_extra_args + 1));
     67   __ JumpToRuntime(ExternalReference(id));
     68 }
     69 
     70 
     71 // Load the built-in Array function from the current context.
     72 static void GenerateLoadArrayFunction(MacroAssembler* masm, Register result) {
     73   // Load the global context.
     74 
     75   __ ldr(result, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
     76   __ ldr(result,
     77          FieldMemOperand(result, GlobalObject::kGlobalContextOffset));
     78   // Load the Array function from the global context.
     79   __ ldr(result,
     80          MemOperand(result,
     81                     Context::SlotOffset(Context::ARRAY_FUNCTION_INDEX)));
     82 }
     83 
     84 
     85 // This constant has the same value as JSArray::kPreallocatedArrayElements and
     86 // if JSArray::kPreallocatedArrayElements is changed handling of loop unfolding
     87 // below should be reconsidered.
     88 static const int kLoopUnfoldLimit = 4;
     89 
     90 
     91 // Allocate an empty JSArray. The allocated array is put into the result
     92 // register. An elements backing store is allocated with size initial_capacity
     93 // and filled with the hole values.
     94 static void AllocateEmptyJSArray(MacroAssembler* masm,
     95                                  Register array_function,
     96                                  Register result,
     97                                  Register scratch1,
     98                                  Register scratch2,
     99                                  Register scratch3,
    100                                  int initial_capacity,
    101                                  Label* gc_required) {
    102   ASSERT(initial_capacity > 0);
    103   // Load the initial map from the array function.
    104   __ ldr(scratch1, FieldMemOperand(array_function,
    105                                    JSFunction::kPrototypeOrInitialMapOffset));
    106 
    107   // Allocate the JSArray object together with space for a fixed array with the
    108   // requested elements.
    109   int size = JSArray::kSize + FixedArray::SizeFor(initial_capacity);
    110   __ AllocateInNewSpace(size / kPointerSize,
    111                         result,
    112                         scratch2,
    113                         scratch3,
    114                         gc_required,
    115                         TAG_OBJECT);
    116 
    117   // Allocated the JSArray. Now initialize the fields except for the elements
    118   // array.
    119   // result: JSObject
    120   // scratch1: initial map
    121   // scratch2: start of next object
    122   __ str(scratch1, FieldMemOperand(result, JSObject::kMapOffset));
    123   __ LoadRoot(scratch1, Heap::kEmptyFixedArrayRootIndex);
    124   __ str(scratch1, FieldMemOperand(result, JSArray::kPropertiesOffset));
    125   // Field JSArray::kElementsOffset is initialized later.
    126   __ mov(scratch3,  Operand(0));
    127   __ str(scratch3, FieldMemOperand(result, JSArray::kLengthOffset));
    128 
    129   // Calculate the location of the elements array and set elements array member
    130   // of the JSArray.
    131   // result: JSObject
    132   // scratch2: start of next object
    133   __ lea(scratch1, MemOperand(result, JSArray::kSize));
    134   __ str(scratch1, FieldMemOperand(result, JSArray::kElementsOffset));
    135 
    136   // Clear the heap tag on the elements array.
    137   __ and_(scratch1, scratch1, Operand(~kHeapObjectTagMask));
    138 
    139   // Initialize the FixedArray and fill it with holes. FixedArray length is not
    140   // stored as a smi.
    141   // result: JSObject
    142   // scratch1: elements array (untagged)
    143   // scratch2: start of next object
    144   __ LoadRoot(scratch3, Heap::kFixedArrayMapRootIndex);
    145   ASSERT_EQ(0 * kPointerSize, FixedArray::kMapOffset);
    146   __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
    147   __ mov(scratch3,  Operand(initial_capacity));
    148   ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
    149   __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
    150 
    151   // Fill the FixedArray with the hole value.
    152   ASSERT_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
    153   ASSERT(initial_capacity <= kLoopUnfoldLimit);
    154   __ LoadRoot(scratch3, Heap::kTheHoleValueRootIndex);
    155   for (int i = 0; i < initial_capacity; i++) {
    156     __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
    157   }
    158 }
    159 
    160 // Allocate a JSArray with the number of elements stored in a register. The
    161 // register array_function holds the built-in Array function and the register
    162 // array_size holds the size of the array as a smi. The allocated array is put
    163 // into the result register and beginning and end of the FixedArray elements
    164 // storage is put into registers elements_array_storage and elements_array_end
    165 // (see  below for when that is not the case). If the parameter fill_with_holes
    166 // is true the allocated elements backing store is filled with the hole values
    167 // otherwise it is left uninitialized. When the backing store is filled the
    168 // register elements_array_storage is scratched.
    169 static void AllocateJSArray(MacroAssembler* masm,
    170                             Register array_function,  // Array function.
    171                             Register array_size,  // As a smi.
    172                             Register result,
    173                             Register elements_array_storage,
    174                             Register elements_array_end,
    175                             Register scratch1,
    176                             Register scratch2,
    177                             bool fill_with_hole,
    178                             Label* gc_required) {
    179   Label not_empty, allocated;
    180 
    181   // Load the initial map from the array function.
    182   __ ldr(elements_array_storage,
    183          FieldMemOperand(array_function,
    184                          JSFunction::kPrototypeOrInitialMapOffset));
    185 
    186   // Check whether an empty sized array is requested.
    187   __ tst(array_size, array_size);
    188   __ b(nz, &not_empty);
    189 
    190   // If an empty array is requested allocate a small elements array anyway. This
    191   // keeps the code below free of special casing for the empty array.
    192   int size = JSArray::kSize +
    193              FixedArray::SizeFor(JSArray::kPreallocatedArrayElements);
    194   __ AllocateInNewSpace(size / kPointerSize,
    195                         result,
    196                         elements_array_end,
    197                         scratch1,
    198                         gc_required,
    199                         TAG_OBJECT);
    200   __ jmp(&allocated);
    201 
    202   // Allocate the JSArray object together with space for a FixedArray with the
    203   // requested number of elements.
    204   __ bind(&not_empty);
    205   ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
    206   __ mov(elements_array_end,
    207          Operand((JSArray::kSize + FixedArray::kHeaderSize) / kPointerSize));
    208   __ add(elements_array_end,
    209          elements_array_end,
    210          Operand(array_size, ASR, kSmiTagSize));
    211   __ AllocateInNewSpace(elements_array_end,
    212                         result,
    213                         scratch1,
    214                         scratch2,
    215                         gc_required,
    216                         TAG_OBJECT);
    217 
    218   // Allocated the JSArray. Now initialize the fields except for the elements
    219   // array.
    220   // result: JSObject
    221   // elements_array_storage: initial map
    222   // array_size: size of array (smi)
    223   __ bind(&allocated);
    224   __ str(elements_array_storage, FieldMemOperand(result, JSObject::kMapOffset));
    225   __ LoadRoot(elements_array_storage, Heap::kEmptyFixedArrayRootIndex);
    226   __ str(elements_array_storage,
    227          FieldMemOperand(result, JSArray::kPropertiesOffset));
    228   // Field JSArray::kElementsOffset is initialized later.
    229   __ str(array_size, FieldMemOperand(result, JSArray::kLengthOffset));
    230 
    231   // Calculate the location of the elements array and set elements array member
    232   // of the JSArray.
    233   // result: JSObject
    234   // array_size: size of array (smi)
    235   __ add(elements_array_storage, result, Operand(JSArray::kSize));
    236   __ str(elements_array_storage,
    237          FieldMemOperand(result, JSArray::kElementsOffset));
    238 
    239   // Clear the heap tag on the elements array.
    240   __ and_(elements_array_storage,
    241           elements_array_storage,
    242           Operand(~kHeapObjectTagMask));
    243   // Initialize the fixed array and fill it with holes. FixedArray length is not
    244   // stored as a smi.
    245   // result: JSObject
    246   // elements_array_storage: elements array (untagged)
    247   // array_size: size of array (smi)
    248   ASSERT(kSmiTag == 0);
    249   __ LoadRoot(scratch1, Heap::kFixedArrayMapRootIndex);
    250   ASSERT_EQ(0 * kPointerSize, FixedArray::kMapOffset);
    251   __ str(scratch1, MemOperand(elements_array_storage, kPointerSize, PostIndex));
    252   // Convert array_size from smi to value.
    253   __ mov(array_size,
    254          Operand(array_size, ASR, kSmiTagSize));
    255   __ tst(array_size, array_size);
    256   // Length of the FixedArray is the number of pre-allocated elements if
    257   // the actual JSArray has length 0 and the size of the JSArray for non-empty
    258   // JSArrays. The length of a FixedArray is not stored as a smi.
    259   __ mov(array_size, Operand(JSArray::kPreallocatedArrayElements), LeaveCC, eq);
    260   ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
    261   __ str(array_size,
    262          MemOperand(elements_array_storage, kPointerSize, PostIndex));
    263 
    264   // Calculate elements array and elements array end.
    265   // result: JSObject
    266   // elements_array_storage: elements array element storage
    267   // array_size: size of elements array
    268   __ add(elements_array_end,
    269          elements_array_storage,
    270          Operand(array_size, LSL, kPointerSizeLog2));
    271 
    272   // Fill the allocated FixedArray with the hole value if requested.
    273   // result: JSObject
    274   // elements_array_storage: elements array element storage
    275   // elements_array_end: start of next object
    276   if (fill_with_hole) {
    277     Label loop, entry;
    278     __ LoadRoot(scratch1, Heap::kTheHoleValueRootIndex);
    279     __ jmp(&entry);
    280     __ bind(&loop);
    281     __ str(scratch1,
    282            MemOperand(elements_array_storage, kPointerSize, PostIndex));
    283     __ bind(&entry);
    284     __ cmp(elements_array_storage, elements_array_end);
    285     __ b(lt, &loop);
    286   }
    287 }
    288 
    289 // Create a new array for the built-in Array function. This function allocates
    290 // the JSArray object and the FixedArray elements array and initializes these.
    291 // If the Array cannot be constructed in native code the runtime is called. This
    292 // function assumes the following state:
    293 //   r0: argc
    294 //   r1: constructor (built-in Array function)
    295 //   lr: return address
    296 //   sp[0]: last argument
    297 // This function is used for both construct and normal calls of Array. The only
    298 // difference between handling a construct call and a normal call is that for a
    299 // construct call the constructor function in r1 needs to be preserved for
    300 // entering the generic code. In both cases argc in r0 needs to be preserved.
    301 // Both registers are preserved by this code so no need to differentiate between
    302 // construct call and normal call.
    303 static void ArrayNativeCode(MacroAssembler* masm,
    304                             Label* call_generic_code) {
    305   Label argc_one_or_more, argc_two_or_more;
    306 
    307   // Check for array construction with zero arguments or one.
    308   __ cmp(r0, Operand(0));
    309   __ b(ne, &argc_one_or_more);
    310 
    311   // Handle construction of an empty array.
    312   AllocateEmptyJSArray(masm,
    313                        r1,
    314                        r2,
    315                        r3,
    316                        r4,
    317                        r5,
    318                        JSArray::kPreallocatedArrayElements,
    319                        call_generic_code);
    320   __ IncrementCounter(&Counters::array_function_native, 1, r3, r4);
    321   // Setup return value, remove receiver from stack and return.
    322   __ mov(r0, r2);
    323   __ add(sp, sp, Operand(kPointerSize));
    324   __ Jump(lr);
    325 
    326   // Check for one argument. Bail out if argument is not smi or if it is
    327   // negative.
    328   __ bind(&argc_one_or_more);
    329   __ cmp(r0, Operand(1));
    330   __ b(ne, &argc_two_or_more);
    331   ASSERT(kSmiTag == 0);
    332   __ ldr(r2, MemOperand(sp));  // Get the argument from the stack.
    333   __ and_(r3, r2, Operand(kIntptrSignBit | kSmiTagMask), SetCC);
    334   __ b(ne, call_generic_code);
    335 
    336   // Handle construction of an empty array of a certain size. Bail out if size
    337   // is too large to actually allocate an elements array.
    338   ASSERT(kSmiTag == 0);
    339   __ cmp(r2, Operand(JSObject::kInitialMaxFastElementArray << kSmiTagSize));
    340   __ b(ge, call_generic_code);
    341 
    342   // r0: argc
    343   // r1: constructor
    344   // r2: array_size (smi)
    345   // sp[0]: argument
    346   AllocateJSArray(masm,
    347                   r1,
    348                   r2,
    349                   r3,
    350                   r4,
    351                   r5,
    352                   r6,
    353                   r7,
    354                   true,
    355                   call_generic_code);
    356   __ IncrementCounter(&Counters::array_function_native, 1, r2, r4);
    357   // Setup return value, remove receiver and argument from stack and return.
    358   __ mov(r0, r3);
    359   __ add(sp, sp, Operand(2 * kPointerSize));
    360   __ Jump(lr);
    361 
    362   // Handle construction of an array from a list of arguments.
    363   __ bind(&argc_two_or_more);
    364   __ mov(r2, Operand(r0, LSL, kSmiTagSize));  // Convet argc to a smi.
    365 
    366   // r0: argc
    367   // r1: constructor
    368   // r2: array_size (smi)
    369   // sp[0]: last argument
    370   AllocateJSArray(masm,
    371                   r1,
    372                   r2,
    373                   r3,
    374                   r4,
    375                   r5,
    376                   r6,
    377                   r7,
    378                   false,
    379                   call_generic_code);
    380   __ IncrementCounter(&Counters::array_function_native, 1, r2, r6);
    381 
    382   // Fill arguments as array elements. Copy from the top of the stack (last
    383   // element) to the array backing store filling it backwards. Note:
    384   // elements_array_end points after the backing store therefore PreIndex is
    385   // used when filling the backing store.
    386   // r0: argc
    387   // r3: JSArray
    388   // r4: elements_array storage start (untagged)
    389   // r5: elements_array_end (untagged)
    390   // sp[0]: last argument
    391   Label loop, entry;
    392   __ jmp(&entry);
    393   __ bind(&loop);
    394   __ ldr(r2, MemOperand(sp, kPointerSize, PostIndex));
    395   __ str(r2, MemOperand(r5, -kPointerSize, PreIndex));
    396   __ bind(&entry);
    397   __ cmp(r4, r5);
    398   __ b(lt, &loop);
    399 
    400   // Remove caller arguments and receiver from the stack, setup return value and
    401   // return.
    402   // r0: argc
    403   // r3: JSArray
    404   // sp[0]: receiver
    405   __ add(sp, sp, Operand(kPointerSize));
    406   __ mov(r0, r3);
    407   __ Jump(lr);
    408 }
    409 
    410 
    411 void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
    412   // ----------- S t a t e -------------
    413   //  -- r0     : number of arguments
    414   //  -- lr     : return address
    415   //  -- sp[...]: constructor arguments
    416   // -----------------------------------
    417   Label generic_array_code, one_or_more_arguments, two_or_more_arguments;
    418 
    419   // Get the Array function.
    420   GenerateLoadArrayFunction(masm, r1);
    421 
    422   if (FLAG_debug_code) {
    423     // Initial map for the builtin Array function shoud be a map.
    424     __ ldr(r2, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
    425     __ tst(r2, Operand(kSmiTagMask));
    426     __ Assert(ne, "Unexpected initial map for Array function");
    427     __ CompareObjectType(r2, r3, r4, MAP_TYPE);
    428     __ Assert(eq, "Unexpected initial map for Array function");
    429   }
    430 
    431   // Run the native code for the Array function called as a normal function.
    432   ArrayNativeCode(masm, &generic_array_code);
    433 
    434   // Jump to the generic array code if the specialized code cannot handle
    435   // the construction.
    436   __ bind(&generic_array_code);
    437   Code* code = Builtins::builtin(Builtins::ArrayCodeGeneric);
    438   Handle<Code> array_code(code);
    439   __ Jump(array_code, RelocInfo::CODE_TARGET);
    440 }
    441 
    442 
    443 void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
    444   // ----------- S t a t e -------------
    445   //  -- r0     : number of arguments
    446   //  -- r1     : constructor function
    447   //  -- lr     : return address
    448   //  -- sp[...]: constructor arguments
    449   // -----------------------------------
    450   Label generic_constructor;
    451 
    452   if (FLAG_debug_code) {
    453     // The array construct code is only set for the builtin Array function which
    454     // always have a map.
    455     GenerateLoadArrayFunction(masm, r2);
    456     __ cmp(r1, r2);
    457     __ Assert(eq, "Unexpected Array function");
    458     // Initial map for the builtin Array function should be a map.
    459     __ ldr(r2, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
    460     __ tst(r2, Operand(kSmiTagMask));
    461     __ Assert(ne, "Unexpected initial map for Array function");
    462     __ CompareObjectType(r2, r3, r4, MAP_TYPE);
    463     __ Assert(eq, "Unexpected initial map for Array function");
    464   }
    465 
    466   // Run the native code for the Array function called as a constructor.
    467   ArrayNativeCode(masm, &generic_constructor);
    468 
    469   // Jump to the generic construct code in case the specialized code cannot
    470   // handle the construction.
    471   __ bind(&generic_constructor);
    472   Code* code = Builtins::builtin(Builtins::JSConstructStubGeneric);
    473   Handle<Code> generic_construct_stub(code);
    474   __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
    475 }
    476 
    477 
    478 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
    479   // ----------- S t a t e -------------
    480   //  -- r0     : number of arguments
    481   //  -- r1     : constructor function
    482   //  -- lr     : return address
    483   //  -- sp[...]: constructor arguments
    484   // -----------------------------------
    485 
    486   Label non_function_call;
    487   // Check that the function is not a smi.
    488   __ tst(r1, Operand(kSmiTagMask));
    489   __ b(eq, &non_function_call);
    490   // Check that the function is a JSFunction.
    491   __ CompareObjectType(r1, r2, r2, JS_FUNCTION_TYPE);
    492   __ b(ne, &non_function_call);
    493 
    494   // Jump to the function-specific construct stub.
    495   __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
    496   __ ldr(r2, FieldMemOperand(r2, SharedFunctionInfo::kConstructStubOffset));
    497   __ add(pc, r2, Operand(Code::kHeaderSize - kHeapObjectTag));
    498 
    499   // r0: number of arguments
    500   // r1: called object
    501   __ bind(&non_function_call);
    502   // CALL_NON_FUNCTION expects the non-function constructor as receiver
    503   // (instead of the original receiver from the call site).  The receiver is
    504   // stack element argc.
    505   __ str(r1, MemOperand(sp, r0, LSL, kPointerSizeLog2));
    506   // Set expected number of arguments to zero (not changing r0).
    507   __ mov(r2, Operand(0));
    508   __ GetBuiltinEntry(r3, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
    509   __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
    510           RelocInfo::CODE_TARGET);
    511 }
    512 
    513 
    514 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
    515                                            bool is_api_function) {
    516   // Enter a construct frame.
    517   __ EnterConstructFrame();
    518 
    519   // Preserve the two incoming parameters on the stack.
    520   __ mov(r0, Operand(r0, LSL, kSmiTagSize));
    521   __ push(r0);  // Smi-tagged arguments count.
    522   __ push(r1);  // Constructor function.
    523 
    524   // Use r7 for holding undefined which is used in several places below.
    525   __ LoadRoot(r7, Heap::kUndefinedValueRootIndex);
    526 
    527   // Try to allocate the object without transitioning into C code. If any of the
    528   // preconditions is not met, the code bails out to the runtime call.
    529   Label rt_call, allocated;
    530   if (FLAG_inline_new) {
    531     Label undo_allocation;
    532 #ifdef ENABLE_DEBUGGER_SUPPORT
    533     ExternalReference debug_step_in_fp =
    534         ExternalReference::debug_step_in_fp_address();
    535     __ mov(r2, Operand(debug_step_in_fp));
    536     __ ldr(r2, MemOperand(r2));
    537     __ tst(r2, r2);
    538     __ b(nz, &rt_call);
    539 #endif
    540 
    541     // Load the initial map and verify that it is in fact a map.
    542     // r1: constructor function
    543     // r7: undefined
    544     __ ldr(r2, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
    545     __ tst(r2, Operand(kSmiTagMask));
    546     __ b(eq, &rt_call);
    547     __ CompareObjectType(r2, r3, r4, MAP_TYPE);
    548     __ b(ne, &rt_call);
    549 
    550     // Check that the constructor is not constructing a JSFunction (see comments
    551     // in Runtime_NewObject in runtime.cc). In which case the initial map's
    552     // instance type would be JS_FUNCTION_TYPE.
    553     // r1: constructor function
    554     // r2: initial map
    555     // r7: undefined
    556     __ CompareInstanceType(r2, r3, JS_FUNCTION_TYPE);
    557     __ b(eq, &rt_call);
    558 
    559     // Now allocate the JSObject on the heap.
    560     // r1: constructor function
    561     // r2: initial map
    562     // r7: undefined
    563     __ ldrb(r3, FieldMemOperand(r2, Map::kInstanceSizeOffset));
    564     __ AllocateInNewSpace(r3, r4, r5, r6, &rt_call, NO_ALLOCATION_FLAGS);
    565 
    566     // Allocated the JSObject, now initialize the fields. Map is set to initial
    567     // map and properties and elements are set to empty fixed array.
    568     // r1: constructor function
    569     // r2: initial map
    570     // r3: object size
    571     // r4: JSObject (not tagged)
    572     // r7: undefined
    573     __ LoadRoot(r6, Heap::kEmptyFixedArrayRootIndex);
    574     __ mov(r5, r4);
    575     ASSERT_EQ(0 * kPointerSize, JSObject::kMapOffset);
    576     __ str(r2, MemOperand(r5, kPointerSize, PostIndex));
    577     ASSERT_EQ(1 * kPointerSize, JSObject::kPropertiesOffset);
    578     __ str(r6, MemOperand(r5, kPointerSize, PostIndex));
    579     ASSERT_EQ(2 * kPointerSize, JSObject::kElementsOffset);
    580     __ str(r6, MemOperand(r5, kPointerSize, PostIndex));
    581 
    582     // Fill all the in-object properties with undefined.
    583     // r1: constructor function
    584     // r2: initial map
    585     // r3: object size (in words)
    586     // r4: JSObject (not tagged)
    587     // r5: First in-object property of JSObject (not tagged)
    588     // r7: undefined
    589     __ add(r6, r4, Operand(r3, LSL, kPointerSizeLog2));  // End of object.
    590     ASSERT_EQ(3 * kPointerSize, JSObject::kHeaderSize);
    591     { Label loop, entry;
    592       __ b(&entry);
    593       __ bind(&loop);
    594       __ str(r7, MemOperand(r5, kPointerSize, PostIndex));
    595       __ bind(&entry);
    596       __ cmp(r5, Operand(r6));
    597       __ b(lt, &loop);
    598     }
    599 
    600     // Add the object tag to make the JSObject real, so that we can continue and
    601     // jump into the continuation code at any time from now on. Any failures
    602     // need to undo the allocation, so that the heap is in a consistent state
    603     // and verifiable.
    604     __ add(r4, r4, Operand(kHeapObjectTag));
    605 
    606     // Check if a non-empty properties array is needed. Continue with allocated
    607     // object if not fall through to runtime call if it is.
    608     // r1: constructor function
    609     // r4: JSObject
    610     // r5: start of next object (not tagged)
    611     // r7: undefined
    612     __ ldrb(r3, FieldMemOperand(r2, Map::kUnusedPropertyFieldsOffset));
    613     // The field instance sizes contains both pre-allocated property fields and
    614     // in-object properties.
    615     __ ldr(r0, FieldMemOperand(r2, Map::kInstanceSizesOffset));
    616     __ and_(r6,
    617             r0,
    618             Operand(0x000000FF << Map::kPreAllocatedPropertyFieldsByte * 8));
    619     __ add(r3, r3, Operand(r6, LSR, Map::kPreAllocatedPropertyFieldsByte * 8));
    620     __ and_(r6, r0, Operand(0x000000FF << Map::kInObjectPropertiesByte * 8));
    621     __ sub(r3, r3, Operand(r6, LSR, Map::kInObjectPropertiesByte * 8), SetCC);
    622 
    623     // Done if no extra properties are to be allocated.
    624     __ b(eq, &allocated);
    625     __ Assert(pl, "Property allocation count failed.");
    626 
    627     // Scale the number of elements by pointer size and add the header for
    628     // FixedArrays to the start of the next object calculation from above.
    629     // r1: constructor
    630     // r3: number of elements in properties array
    631     // r4: JSObject
    632     // r5: start of next object
    633     // r7: undefined
    634     __ add(r0, r3, Operand(FixedArray::kHeaderSize / kPointerSize));
    635     __ AllocateInNewSpace(r0,
    636                           r5,
    637                           r6,
    638                           r2,
    639                           &undo_allocation,
    640                           RESULT_CONTAINS_TOP);
    641 
    642     // Initialize the FixedArray.
    643     // r1: constructor
    644     // r3: number of elements in properties array
    645     // r4: JSObject
    646     // r5: FixedArray (not tagged)
    647     // r7: undefined
    648     __ LoadRoot(r6, Heap::kFixedArrayMapRootIndex);
    649     __ mov(r2, r5);
    650     ASSERT_EQ(0 * kPointerSize, JSObject::kMapOffset);
    651     __ str(r6, MemOperand(r2, kPointerSize, PostIndex));
    652     ASSERT_EQ(1 * kPointerSize, Array::kLengthOffset);
    653     __ str(r3, MemOperand(r2, kPointerSize, PostIndex));
    654 
    655     // Initialize the fields to undefined.
    656     // r1: constructor function
    657     // r2: First element of FixedArray (not tagged)
    658     // r3: number of elements in properties array
    659     // r4: JSObject
    660     // r5: FixedArray (not tagged)
    661     // r7: undefined
    662     __ add(r6, r2, Operand(r3, LSL, kPointerSizeLog2));  // End of object.
    663     ASSERT_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
    664     { Label loop, entry;
    665       __ b(&entry);
    666       __ bind(&loop);
    667       __ str(r7, MemOperand(r2, kPointerSize, PostIndex));
    668       __ bind(&entry);
    669       __ cmp(r2, Operand(r6));
    670       __ b(lt, &loop);
    671     }
    672 
    673     // Store the initialized FixedArray into the properties field of
    674     // the JSObject
    675     // r1: constructor function
    676     // r4: JSObject
    677     // r5: FixedArray (not tagged)
    678     __ add(r5, r5, Operand(kHeapObjectTag));  // Add the heap tag.
    679     __ str(r5, FieldMemOperand(r4, JSObject::kPropertiesOffset));
    680 
    681     // Continue with JSObject being successfully allocated
    682     // r1: constructor function
    683     // r4: JSObject
    684     __ jmp(&allocated);
    685 
    686     // Undo the setting of the new top so that the heap is verifiable. For
    687     // example, the map's unused properties potentially do not match the
    688     // allocated objects unused properties.
    689     // r4: JSObject (previous new top)
    690     __ bind(&undo_allocation);
    691     __ UndoAllocationInNewSpace(r4, r5);
    692   }
    693 
    694   // Allocate the new receiver object using the runtime call.
    695   // r1: constructor function
    696   __ bind(&rt_call);
    697   __ push(r1);  // argument for Runtime_NewObject
    698   __ CallRuntime(Runtime::kNewObject, 1);
    699   __ mov(r4, r0);
    700 
    701   // Receiver for constructor call allocated.
    702   // r4: JSObject
    703   __ bind(&allocated);
    704   __ push(r4);
    705 
    706   // Push the function and the allocated receiver from the stack.
    707   // sp[0]: receiver (newly allocated object)
    708   // sp[1]: constructor function
    709   // sp[2]: number of arguments (smi-tagged)
    710   __ ldr(r1, MemOperand(sp, kPointerSize));
    711   __ push(r1);  // Constructor function.
    712   __ push(r4);  // Receiver.
    713 
    714   // Reload the number of arguments from the stack.
    715   // r1: constructor function
    716   // sp[0]: receiver
    717   // sp[1]: constructor function
    718   // sp[2]: receiver
    719   // sp[3]: constructor function
    720   // sp[4]: number of arguments (smi-tagged)
    721   __ ldr(r3, MemOperand(sp, 4 * kPointerSize));
    722 
    723   // Setup pointer to last argument.
    724   __ add(r2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
    725 
    726   // Setup number of arguments for function call below
    727   __ mov(r0, Operand(r3, LSR, kSmiTagSize));
    728 
    729   // Copy arguments and receiver to the expression stack.
    730   // r0: number of arguments
    731   // r2: address of last argument (caller sp)
    732   // r1: constructor function
    733   // r3: number of arguments (smi-tagged)
    734   // sp[0]: receiver
    735   // sp[1]: constructor function
    736   // sp[2]: receiver
    737   // sp[3]: constructor function
    738   // sp[4]: number of arguments (smi-tagged)
    739   Label loop, entry;
    740   __ b(&entry);
    741   __ bind(&loop);
    742   __ ldr(ip, MemOperand(r2, r3, LSL, kPointerSizeLog2 - 1));
    743   __ push(ip);
    744   __ bind(&entry);
    745   __ sub(r3, r3, Operand(2), SetCC);
    746   __ b(ge, &loop);
    747 
    748   // Call the function.
    749   // r0: number of arguments
    750   // r1: constructor function
    751   if (is_api_function) {
    752     __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
    753     Handle<Code> code = Handle<Code>(
    754         Builtins::builtin(Builtins::HandleApiCallConstruct));
    755     ParameterCount expected(0);
    756     __ InvokeCode(code, expected, expected,
    757                   RelocInfo::CODE_TARGET, CALL_FUNCTION);
    758   } else {
    759     ParameterCount actual(r0);
    760     __ InvokeFunction(r1, actual, CALL_FUNCTION);
    761   }
    762 
    763   // Pop the function from the stack.
    764   // sp[0]: constructor function
    765   // sp[2]: receiver
    766   // sp[3]: constructor function
    767   // sp[4]: number of arguments (smi-tagged)
    768   __ pop();
    769 
    770   // Restore context from the frame.
    771   // r0: result
    772   // sp[0]: receiver
    773   // sp[1]: constructor function
    774   // sp[2]: number of arguments (smi-tagged)
    775   __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
    776 
    777   // If the result is an object (in the ECMA sense), we should get rid
    778   // of the receiver and use the result; see ECMA-262 section 13.2.2-7
    779   // on page 74.
    780   Label use_receiver, exit;
    781 
    782   // If the result is a smi, it is *not* an object in the ECMA sense.
    783   // r0: result
    784   // sp[0]: receiver (newly allocated object)
    785   // sp[1]: constructor function
    786   // sp[2]: number of arguments (smi-tagged)
    787   __ tst(r0, Operand(kSmiTagMask));
    788   __ b(eq, &use_receiver);
    789 
    790   // If the type of the result (stored in its map) is less than
    791   // FIRST_JS_OBJECT_TYPE, it is not an object in the ECMA sense.
    792   __ CompareObjectType(r0, r3, r3, FIRST_JS_OBJECT_TYPE);
    793   __ b(ge, &exit);
    794 
    795   // Throw away the result of the constructor invocation and use the
    796   // on-stack receiver as the result.
    797   __ bind(&use_receiver);
    798   __ ldr(r0, MemOperand(sp));
    799 
    800   // Remove receiver from the stack, remove caller arguments, and
    801   // return.
    802   __ bind(&exit);
    803   // r0: result
    804   // sp[0]: receiver (newly allocated object)
    805   // sp[1]: constructor function
    806   // sp[2]: number of arguments (smi-tagged)
    807   __ ldr(r1, MemOperand(sp, 2 * kPointerSize));
    808   __ LeaveConstructFrame();
    809   __ add(sp, sp, Operand(r1, LSL, kPointerSizeLog2 - 1));
    810   __ add(sp, sp, Operand(kPointerSize));
    811   __ IncrementCounter(&Counters::constructed_objects, 1, r1, r2);
    812   __ Jump(lr);
    813 }
    814 
    815 
    816 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
    817   Generate_JSConstructStubHelper(masm, false);
    818 }
    819 
    820 
    821 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
    822   Generate_JSConstructStubHelper(masm, true);
    823 }
    824 
    825 
    826 static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
    827                                              bool is_construct) {
    828   // Called from Generate_JS_Entry
    829   // r0: code entry
    830   // r1: function
    831   // r2: receiver
    832   // r3: argc
    833   // r4: argv
    834   // r5-r7, cp may be clobbered
    835 
    836   // Clear the context before we push it when entering the JS frame.
    837   __ mov(cp, Operand(0));
    838 
    839   // Enter an internal frame.
    840   __ EnterInternalFrame();
    841 
    842   // Set up the context from the function argument.
    843   __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
    844 
    845   // Set up the roots register.
    846   ExternalReference roots_address = ExternalReference::roots_address();
    847   __ mov(r10, Operand(roots_address));
    848 
    849   // Push the function and the receiver onto the stack.
    850   __ push(r1);
    851   __ push(r2);
    852 
    853   // Copy arguments to the stack in a loop.
    854   // r1: function
    855   // r3: argc
    856   // r4: argv, i.e. points to first arg
    857   Label loop, entry;
    858   __ add(r2, r4, Operand(r3, LSL, kPointerSizeLog2));
    859   // r2 points past last arg.
    860   __ b(&entry);
    861   __ bind(&loop);
    862   __ ldr(r0, MemOperand(r4, kPointerSize, PostIndex));  // read next parameter
    863   __ ldr(r0, MemOperand(r0));  // dereference handle
    864   __ push(r0);  // push parameter
    865   __ bind(&entry);
    866   __ cmp(r4, Operand(r2));
    867   __ b(ne, &loop);
    868 
    869   // Initialize all JavaScript callee-saved registers, since they will be seen
    870   // by the garbage collector as part of handlers.
    871   __ LoadRoot(r4, Heap::kUndefinedValueRootIndex);
    872   __ mov(r5, Operand(r4));
    873   __ mov(r6, Operand(r4));
    874   __ mov(r7, Operand(r4));
    875   if (kR9Available == 1) {
    876     __ mov(r9, Operand(r4));
    877   }
    878 
    879   // Invoke the code and pass argc as r0.
    880   __ mov(r0, Operand(r3));
    881   if (is_construct) {
    882     __ Call(Handle<Code>(Builtins::builtin(Builtins::JSConstructCall)),
    883             RelocInfo::CODE_TARGET);
    884   } else {
    885     ParameterCount actual(r0);
    886     __ InvokeFunction(r1, actual, CALL_FUNCTION);
    887   }
    888 
    889   // Exit the JS frame and remove the parameters (except function), and return.
    890   // Respect ABI stack constraint.
    891   __ LeaveInternalFrame();
    892   __ Jump(lr);
    893 
    894   // r0: result
    895 }
    896 
    897 
    898 void Builtins::Generate_JSEntryTrampoline(MacroAssembler* masm) {
    899   Generate_JSEntryTrampolineHelper(masm, false);
    900 }
    901 
    902 
    903 void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
    904   Generate_JSEntryTrampolineHelper(masm, true);
    905 }
    906 
    907 
    908 void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
    909   // 1. Make sure we have at least one argument.
    910   // r0: actual number of arguments
    911   { Label done;
    912     __ tst(r0, Operand(r0));
    913     __ b(ne, &done);
    914     __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
    915     __ push(r2);
    916     __ add(r0, r0, Operand(1));
    917     __ bind(&done);
    918   }
    919 
    920   // 2. Get the function to call (passed as receiver) from the stack, check
    921   //    if it is a function.
    922   // r0: actual number of arguments
    923   Label non_function;
    924   __ ldr(r1, MemOperand(sp, r0, LSL, kPointerSizeLog2));
    925   __ tst(r1, Operand(kSmiTagMask));
    926   __ b(eq, &non_function);
    927   __ CompareObjectType(r1, r2, r2, JS_FUNCTION_TYPE);
    928   __ b(ne, &non_function);
    929 
    930   // 3a. Patch the first argument if necessary when calling a function.
    931   // r0: actual number of arguments
    932   // r1: function
    933   Label shift_arguments;
    934   { Label convert_to_object, use_global_receiver, patch_receiver;
    935     // Change context eagerly in case we need the global receiver.
    936     __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
    937 
    938     __ add(r2, sp, Operand(r0, LSL, kPointerSizeLog2));
    939     __ ldr(r2, MemOperand(r2, -kPointerSize));
    940     // r0: actual number of arguments
    941     // r1: function
    942     // r2: first argument
    943     __ tst(r2, Operand(kSmiTagMask));
    944     __ b(eq, &convert_to_object);
    945 
    946     __ LoadRoot(r3, Heap::kNullValueRootIndex);
    947     __ cmp(r2, r3);
    948     __ b(eq, &use_global_receiver);
    949     __ LoadRoot(r3, Heap::kUndefinedValueRootIndex);
    950     __ cmp(r2, r3);
    951     __ b(eq, &use_global_receiver);
    952 
    953     __ CompareObjectType(r2, r3, r3, FIRST_JS_OBJECT_TYPE);
    954     __ b(lt, &convert_to_object);
    955     __ cmp(r3, Operand(LAST_JS_OBJECT_TYPE));
    956     __ b(le, &shift_arguments);
    957 
    958     __ bind(&convert_to_object);
    959     __ EnterInternalFrame();  // In order to preserve argument count.
    960     __ mov(r0, Operand(r0, LSL, kSmiTagSize));  // Smi-tagged.
    961     __ push(r0);
    962 
    963     __ push(r2);
    964     __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_JS);
    965     __ mov(r2, r0);
    966 
    967     __ pop(r0);
    968     __ mov(r0, Operand(r0, ASR, kSmiTagSize));
    969     __ LeaveInternalFrame();
    970     // Restore the function to r1.
    971     __ ldr(r1, MemOperand(sp, r0, LSL, kPointerSizeLog2));
    972     __ jmp(&patch_receiver);
    973 
    974     // Use the global receiver object from the called function as the
    975     // receiver.
    976     __ bind(&use_global_receiver);
    977     const int kGlobalIndex =
    978         Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
    979     __ ldr(r2, FieldMemOperand(cp, kGlobalIndex));
    980     __ ldr(r2, FieldMemOperand(r2, GlobalObject::kGlobalContextOffset));
    981     __ ldr(r2, FieldMemOperand(r2, kGlobalIndex));
    982     __ ldr(r2, FieldMemOperand(r2, GlobalObject::kGlobalReceiverOffset));
    983 
    984     __ bind(&patch_receiver);
    985     __ add(r3, sp, Operand(r0, LSL, kPointerSizeLog2));
    986     __ str(r2, MemOperand(r3, -kPointerSize));
    987 
    988     __ jmp(&shift_arguments);
    989   }
    990 
    991   // 3b. Patch the first argument when calling a non-function.  The
    992   //     CALL_NON_FUNCTION builtin expects the non-function callee as
    993   //     receiver, so overwrite the first argument which will ultimately
    994   //     become the receiver.
    995   // r0: actual number of arguments
    996   // r1: function
    997   __ bind(&non_function);
    998   __ add(r2, sp, Operand(r0, LSL, kPointerSizeLog2));
    999   __ str(r1, MemOperand(r2, -kPointerSize));
   1000   // Clear r1 to indicate a non-function being called.
   1001   __ mov(r1, Operand(0));
   1002 
   1003   // 4. Shift arguments and return address one slot down on the stack
   1004   //    (overwriting the original receiver).  Adjust argument count to make
   1005   //    the original first argument the new receiver.
   1006   // r0: actual number of arguments
   1007   // r1: function
   1008   __ bind(&shift_arguments);
   1009   { Label loop;
   1010     // Calculate the copy start address (destination). Copy end address is sp.
   1011     __ add(r2, sp, Operand(r0, LSL, kPointerSizeLog2));
   1012 
   1013     __ bind(&loop);
   1014     __ ldr(ip, MemOperand(r2, -kPointerSize));
   1015     __ str(ip, MemOperand(r2));
   1016     __ sub(r2, r2, Operand(kPointerSize));
   1017     __ cmp(r2, sp);
   1018     __ b(ne, &loop);
   1019     // Adjust the actual number of arguments and remove the top element
   1020     // (which is a copy of the last argument).
   1021     __ sub(r0, r0, Operand(1));
   1022     __ pop();
   1023   }
   1024 
   1025   // 5a. Call non-function via tail call to CALL_NON_FUNCTION builtin.
   1026   // r0: actual number of arguments
   1027   // r1: function
   1028   { Label function;
   1029     __ tst(r1, r1);
   1030     __ b(ne, &function);
   1031     __ mov(r2, Operand(0));  // expected arguments is 0 for CALL_NON_FUNCTION
   1032     __ GetBuiltinEntry(r3, Builtins::CALL_NON_FUNCTION);
   1033     __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
   1034                          RelocInfo::CODE_TARGET);
   1035     __ bind(&function);
   1036   }
   1037 
   1038   // 5b. Get the code to call from the function and check that the number of
   1039   //     expected arguments matches what we're providing.  If so, jump
   1040   //     (tail-call) to the code in register edx without checking arguments.
   1041   // r0: actual number of arguments
   1042   // r1: function
   1043   __ ldr(r3, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
   1044   __ ldr(r2,
   1045          FieldMemOperand(r3, SharedFunctionInfo::kFormalParameterCountOffset));
   1046   __ ldr(r3, FieldMemOperand(r3, SharedFunctionInfo::kCodeOffset));
   1047   __ add(r3, r3, Operand(Code::kHeaderSize - kHeapObjectTag));
   1048   __ cmp(r2, r0);  // Check formal and actual parameter counts.
   1049   __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
   1050           RelocInfo::CODE_TARGET, ne);
   1051 
   1052   ParameterCount expected(0);
   1053   __ InvokeCode(r3, expected, expected, JUMP_FUNCTION);
   1054 }
   1055 
   1056 
   1057 void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
   1058   const int kIndexOffset    = -5 * kPointerSize;
   1059   const int kLimitOffset    = -4 * kPointerSize;
   1060   const int kArgsOffset     =  2 * kPointerSize;
   1061   const int kRecvOffset     =  3 * kPointerSize;
   1062   const int kFunctionOffset =  4 * kPointerSize;
   1063 
   1064   __ EnterInternalFrame();
   1065 
   1066   __ ldr(r0, MemOperand(fp, kFunctionOffset));  // get the function
   1067   __ push(r0);
   1068   __ ldr(r0, MemOperand(fp, kArgsOffset));  // get the args array
   1069   __ push(r0);
   1070   __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_JS);
   1071 
   1072   // Check the stack for overflow. We are not trying need to catch
   1073   // interruptions (e.g. debug break and preemption) here, so the "real stack
   1074   // limit" is checked.
   1075   Label okay;
   1076   __ LoadRoot(r2, Heap::kRealStackLimitRootIndex);
   1077   // Make r2 the space we have left. The stack might already be overflowed
   1078   // here which will cause r2 to become negative.
   1079   __ sub(r2, sp, r2);
   1080   // Check if the arguments will overflow the stack.
   1081   __ cmp(r2, Operand(r0, LSL, kPointerSizeLog2 - kSmiTagSize));
   1082   __ b(gt, &okay);  // Signed comparison.
   1083 
   1084   // Out of stack space.
   1085   __ ldr(r1, MemOperand(fp, kFunctionOffset));
   1086   __ push(r1);
   1087   __ push(r0);
   1088   __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_JS);
   1089   // End of stack check.
   1090 
   1091   // Push current limit and index.
   1092   __ bind(&okay);
   1093   __ push(r0);  // limit
   1094   __ mov(r1, Operand(0));  // initial index
   1095   __ push(r1);
   1096 
   1097   // Change context eagerly to get the right global object if necessary.
   1098   __ ldr(r0, MemOperand(fp, kFunctionOffset));
   1099   __ ldr(cp, FieldMemOperand(r0, JSFunction::kContextOffset));
   1100 
   1101   // Compute the receiver.
   1102   Label call_to_object, use_global_receiver, push_receiver;
   1103   __ ldr(r0, MemOperand(fp, kRecvOffset));
   1104   __ tst(r0, Operand(kSmiTagMask));
   1105   __ b(eq, &call_to_object);
   1106   __ LoadRoot(r1, Heap::kNullValueRootIndex);
   1107   __ cmp(r0, r1);
   1108   __ b(eq, &use_global_receiver);
   1109   __ LoadRoot(r1, Heap::kUndefinedValueRootIndex);
   1110   __ cmp(r0, r1);
   1111   __ b(eq, &use_global_receiver);
   1112 
   1113   // Check if the receiver is already a JavaScript object.
   1114   // r0: receiver
   1115   __ CompareObjectType(r0, r1, r1, FIRST_JS_OBJECT_TYPE);
   1116   __ b(lt, &call_to_object);
   1117   __ cmp(r1, Operand(LAST_JS_OBJECT_TYPE));
   1118   __ b(le, &push_receiver);
   1119 
   1120   // Convert the receiver to a regular object.
   1121   // r0: receiver
   1122   __ bind(&call_to_object);
   1123   __ push(r0);
   1124   __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_JS);
   1125   __ b(&push_receiver);
   1126 
   1127   // Use the current global receiver object as the receiver.
   1128   __ bind(&use_global_receiver);
   1129   const int kGlobalOffset =
   1130       Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
   1131   __ ldr(r0, FieldMemOperand(cp, kGlobalOffset));
   1132   __ ldr(r0, FieldMemOperand(r0, GlobalObject::kGlobalContextOffset));
   1133   __ ldr(r0, FieldMemOperand(r0, kGlobalOffset));
   1134   __ ldr(r0, FieldMemOperand(r0, GlobalObject::kGlobalReceiverOffset));
   1135 
   1136   // Push the receiver.
   1137   // r0: receiver
   1138   __ bind(&push_receiver);
   1139   __ push(r0);
   1140 
   1141   // Copy all arguments from the array to the stack.
   1142   Label entry, loop;
   1143   __ ldr(r0, MemOperand(fp, kIndexOffset));
   1144   __ b(&entry);
   1145 
   1146   // Load the current argument from the arguments array and push it to the
   1147   // stack.
   1148   // r0: current argument index
   1149   __ bind(&loop);
   1150   __ ldr(r1, MemOperand(fp, kArgsOffset));
   1151   __ push(r1);
   1152   __ push(r0);
   1153 
   1154   // Call the runtime to access the property in the arguments array.
   1155   __ CallRuntime(Runtime::kGetProperty, 2);
   1156   __ push(r0);
   1157 
   1158   // Use inline caching to access the arguments.
   1159   __ ldr(r0, MemOperand(fp, kIndexOffset));
   1160   __ add(r0, r0, Operand(1 << kSmiTagSize));
   1161   __ str(r0, MemOperand(fp, kIndexOffset));
   1162 
   1163   // Test if the copy loop has finished copying all the elements from the
   1164   // arguments object.
   1165   __ bind(&entry);
   1166   __ ldr(r1, MemOperand(fp, kLimitOffset));
   1167   __ cmp(r0, r1);
   1168   __ b(ne, &loop);
   1169 
   1170   // Invoke the function.
   1171   ParameterCount actual(r0);
   1172   __ mov(r0, Operand(r0, ASR, kSmiTagSize));
   1173   __ ldr(r1, MemOperand(fp, kFunctionOffset));
   1174   __ InvokeFunction(r1, actual, CALL_FUNCTION);
   1175 
   1176   // Tear down the internal frame and remove function, receiver and args.
   1177   __ LeaveInternalFrame();
   1178   __ add(sp, sp, Operand(3 * kPointerSize));
   1179   __ Jump(lr);
   1180 }
   1181 
   1182 
   1183 static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
   1184   __ mov(r0, Operand(r0, LSL, kSmiTagSize));
   1185   __ mov(r4, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
   1186   __ stm(db_w, sp, r0.bit() | r1.bit() | r4.bit() | fp.bit() | lr.bit());
   1187   __ add(fp, sp, Operand(3 * kPointerSize));
   1188 }
   1189 
   1190 
   1191 static void LeaveArgumentsAdaptorFrame(MacroAssembler* masm) {
   1192   // ----------- S t a t e -------------
   1193   //  -- r0 : result being passed through
   1194   // -----------------------------------
   1195   // Get the number of arguments passed (as a smi), tear down the frame and
   1196   // then tear down the parameters.
   1197   __ ldr(r1, MemOperand(fp, -3 * kPointerSize));
   1198   __ mov(sp, fp);
   1199   __ ldm(ia_w, sp, fp.bit() | lr.bit());
   1200   __ add(sp, sp, Operand(r1, LSL, kPointerSizeLog2 - kSmiTagSize));
   1201   __ add(sp, sp, Operand(kPointerSize));  // adjust for receiver
   1202 }
   1203 
   1204 
   1205 void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
   1206   // ----------- S t a t e -------------
   1207   //  -- r0 : actual number of arguments
   1208   //  -- r1 : function (passed through to callee)
   1209   //  -- r2 : expected number of arguments
   1210   //  -- r3 : code entry to call
   1211   // -----------------------------------
   1212 
   1213   Label invoke, dont_adapt_arguments;
   1214 
   1215   Label enough, too_few;
   1216   __ cmp(r0, Operand(r2));
   1217   __ b(lt, &too_few);
   1218   __ cmp(r2, Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
   1219   __ b(eq, &dont_adapt_arguments);
   1220 
   1221   {  // Enough parameters: actual >= expected
   1222     __ bind(&enough);
   1223     EnterArgumentsAdaptorFrame(masm);
   1224 
   1225     // Calculate copy start address into r0 and copy end address into r2.
   1226     // r0: actual number of arguments as a smi
   1227     // r1: function
   1228     // r2: expected number of arguments
   1229     // r3: code entry to call
   1230     __ add(r0, fp, Operand(r0, LSL, kPointerSizeLog2 - kSmiTagSize));
   1231     // adjust for return address and receiver
   1232     __ add(r0, r0, Operand(2 * kPointerSize));
   1233     __ sub(r2, r0, Operand(r2, LSL, kPointerSizeLog2));
   1234 
   1235     // Copy the arguments (including the receiver) to the new stack frame.
   1236     // r0: copy start address
   1237     // r1: function
   1238     // r2: copy end address
   1239     // r3: code entry to call
   1240 
   1241     Label copy;
   1242     __ bind(&copy);
   1243     __ ldr(ip, MemOperand(r0, 0));
   1244     __ push(ip);
   1245     __ cmp(r0, r2);  // Compare before moving to next argument.
   1246     __ sub(r0, r0, Operand(kPointerSize));
   1247     __ b(ne, &copy);
   1248 
   1249     __ b(&invoke);
   1250   }
   1251 
   1252   {  // Too few parameters: Actual < expected
   1253     __ bind(&too_few);
   1254     EnterArgumentsAdaptorFrame(masm);
   1255 
   1256     // Calculate copy start address into r0 and copy end address is fp.
   1257     // r0: actual number of arguments as a smi
   1258     // r1: function
   1259     // r2: expected number of arguments
   1260     // r3: code entry to call
   1261     __ add(r0, fp, Operand(r0, LSL, kPointerSizeLog2 - kSmiTagSize));
   1262 
   1263     // Copy the arguments (including the receiver) to the new stack frame.
   1264     // r0: copy start address
   1265     // r1: function
   1266     // r2: expected number of arguments
   1267     // r3: code entry to call
   1268     Label copy;
   1269     __ bind(&copy);
   1270     // Adjust load for return address and receiver.
   1271     __ ldr(ip, MemOperand(r0, 2 * kPointerSize));
   1272     __ push(ip);
   1273     __ cmp(r0, fp);  // Compare before moving to next argument.
   1274     __ sub(r0, r0, Operand(kPointerSize));
   1275     __ b(ne, &copy);
   1276 
   1277     // Fill the remaining expected arguments with undefined.
   1278     // r1: function
   1279     // r2: expected number of arguments
   1280     // r3: code entry to call
   1281     __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   1282     __ sub(r2, fp, Operand(r2, LSL, kPointerSizeLog2));
   1283     __ sub(r2, r2, Operand(4 * kPointerSize));  // Adjust for frame.
   1284 
   1285     Label fill;
   1286     __ bind(&fill);
   1287     __ push(ip);
   1288     __ cmp(sp, r2);
   1289     __ b(ne, &fill);
   1290   }
   1291 
   1292   // Call the entry point.
   1293   __ bind(&invoke);
   1294   __ Call(r3);
   1295 
   1296   // Exit frame and return.
   1297   LeaveArgumentsAdaptorFrame(masm);
   1298   __ Jump(lr);
   1299 
   1300 
   1301   // -------------------------------------------
   1302   // Dont adapt arguments.
   1303   // -------------------------------------------
   1304   __ bind(&dont_adapt_arguments);
   1305   __ Jump(r3);
   1306 }
   1307 
   1308 
   1309 #undef __
   1310 
   1311 } }  // namespace v8::internal
   1312