[builtins] Unify the String constructor.

src/mips/builtins-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 123 matching lines @@
 
   // Run the native code for the Array function called as a normal function.
   // Tail call a stub.
   __ mov(a3, a1);
   __ LoadRoot(a2, Heap::kUndefinedValueRootIndex);
   ArrayConstructorStub stub(masm->isolate());
   __ TailCallStub(&stub);
 }
 
 
-void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+// static
+void Builtins::Generate_StringConstructor(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0                     : number of arguments
   //  -- a1                     : constructor function
+  //  -- ra                     : return address
+  //  -- sp[(argc - n - 1) * 4] : arg[n] (zero based)
+  //  -- sp[argc * 4]           : receiver
+  // -----------------------------------
+
+  // 1. Load the first argument into a0 and get rid of the rest (including the
+  // receiver).
+  Label no_arguments;
+  {
+    __ Branch(USE_DELAY_SLOT, &no_arguments, eq, a0, Operand(zero_reg));
+    __ Subu(a0, a0, Operand(1));
+    __ sll(a0, a0, kPointerSizeLog2);
+    __ Addu(sp, a0, sp);
+    __ lw(a0, MemOperand(sp));
+    __ Drop(2);
+  }
+
+  // 2a. At least one argument, return a0 if it's a string, otherwise
+  // dispatch to appropriate conversion.
+  Label to_string, symbol_descriptive_string;
+  {
+    __ JumpIfSmi(a0, &to_string);
+    __ GetObjectType(a0, a1, a1);
+    STATIC_ASSERT(FIRST_NONSTRING_TYPE == SYMBOL_TYPE);
+    __ Subu(a1, a1, Operand(FIRST_NONSTRING_TYPE));
+    __ Branch(&symbol_descriptive_string, eq, a1, Operand(zero_reg));
+    __ Branch(&to_string, gt, a1, Operand(zero_reg));
+    __ Ret(USE_DELAY_SLOT);
+    __ mov(v0, a0);
+  }
+
+  // 2b. No arguments, return the empty string (and pop the receiver).
+  __ bind(&no_arguments);
+  {
+    __ LoadRoot(v0, Heap::kempty_stringRootIndex);
+    __ DropAndRet(1);
+  }
+
+  // 3a. Convert a0 to a string.
+  __ bind(&to_string);
+  {
+    ToStringStub stub(masm->isolate());
+    __ TailCallStub(&stub);
+  }
+
+  // 3b. Convert symbol in a0 to a string.
+  __ bind(&symbol_descriptive_string);
+  {
+    __ Push(a0);
+    __ TailCallRuntime(Runtime::kSymbolDescriptiveString, 1, 1);
+  }
+}
+
+
+// static
+void Builtins::Generate_StringConstructor_ConstructStub(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- a0                     : number of arguments
+  //  -- a1                     : constructor function
   //  -- ra                     : return address
   //  -- sp[(argc - n - 1) * 4] : arg[n] (zero based)
   //  -- sp[argc * 4]           : receiver
   // -----------------------------------
 
   // 1. Load the first argument into a0 and get rid of the rest (including the
   // receiver).
   {
     Label no_arguments, done;
-    __ Branch(&no_arguments, eq, a0, Operand(zero_reg));
+    __ Branch(USE_DELAY_SLOT, &no_arguments, eq, a0, Operand(zero_reg));
     __ Subu(a0, a0, Operand(1));
     __ sll(a0, a0, kPointerSizeLog2);
     __ Addu(sp, a0, sp);
     __ lw(a0, MemOperand(sp));
     __ Drop(2);
     __ jmp(&done);
     __ bind(&no_arguments);
     __ LoadRoot(a0, Heap::kempty_stringRootIndex);
     __ Drop(1);
     __ bind(&done);
@@ skipping 29 matching lines @@
     Label allocate, done_allocate;
     __ Allocate(JSValue::kSize, v0, a2, a3, &allocate, TAG_OBJECT);
     __ bind(&done_allocate);
 
     // Initialize the JSValue in eax.
     __ LoadGlobalFunctionInitialMap(a1, a2, a3);
     __ sw(a2, FieldMemOperand(v0, HeapObject::kMapOffset));
     __ LoadRoot(a3, Heap::kEmptyFixedArrayRootIndex);
     __ sw(a3, FieldMemOperand(v0, JSObject::kPropertiesOffset));
     __ sw(a3, FieldMemOperand(v0, JSObject::kElementsOffset));
+    __ Ret(USE_DELAY_SLOT);
     __ sw(a0, FieldMemOperand(v0, JSValue::kValueOffset));
     STATIC_ASSERT(JSValue::kSize == 4 * kPointerSize);
-    __ Ret();
 
     // Fallback to the runtime to allocate in new space.
     __ bind(&allocate);
     {
       FrameScope scope(masm, StackFrame::INTERNAL);
       __ Move(a2, Smi::FromInt(JSValue::kSize));
       __ Push(a0, a1, a2);
       __ CallRuntime(Runtime::kAllocateInNewSpace, 1);
       __ Pop(a0, a1);
     }
@@ skipping 1580 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS