MIPS: Turn ToNumberStub into a PlatformCodeStub again.

Port 724a15e8bf3fb8697a950c8e0f96158c8e56ec71
Port r25187

The HydrogenCodeStub is too expensive and there's no easy way to reduce
this cost, so turning it into a PlatformCodeStub solves that problem
until we can use TurboFan for code stubs.

TEST=mjsunit
BUG=
R=dusan.milosavljevic@imgtec.com

Review URL: https://codereview.chromium.org/707863002

Cr-Commit-Position: refs/heads/master@{#25202}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25202 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -3351,6 +3351,26 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 }
 
 
+void ToNumberStub::Generate(MacroAssembler* masm) {
+  // The ToNumber stub takes one argument in a0.
+  Label check_heap_number, call_builtin;
+  __ JumpIfNotSmi(a0, &check_heap_number);
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, a0);
+
+  __ bind(&check_heap_number);
+  __ lw(a1, FieldMemOperand(a0, HeapObject::kMapOffset));
+  __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
+  __ Branch(&call_builtin, ne, a1, Operand(at));
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, a0);
+
+  __ bind(&call_builtin);
+  __ push(a0);
+  __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_FUNCTION);
+}
+
+
 void StringHelper::GenerateFlatOneByteStringEquals(
     MacroAssembler* masm, Register left, Register right, Register scratch1,
     Register scratch2, Register scratch3) {

src/mips64/code-stubs-mips64.cc

@@ -3376,6 +3376,26 @@ void SubStringStub::Generate(MacroAssembler* masm) {
 }
 
 
+void ToNumberStub::Generate(MacroAssembler* masm) {
+  // The ToNumber stub takes one argument in a0.
+  Label check_heap_number, call_builtin;
+  __ JumpIfNotSmi(a0, &check_heap_number);
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, a0);
+
+  __ bind(&check_heap_number);
+  __ ld(a1, FieldMemOperand(a0, HeapObject::kMapOffset));
+  __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
+  __ Branch(&call_builtin, ne, a1, Operand(at));
+  __ Ret(USE_DELAY_SLOT);
+  __ mov(v0, a0);
+
+  __ bind(&call_builtin);
+  __ push(a0);
+  __ InvokeBuiltin(Builtins::TO_NUMBER, JUMP_FUNCTION);
+}
+
+
 void StringHelper::GenerateFlatOneByteStringEquals(
     MacroAssembler* masm, Register left, Register right, Register scratch1,
     Register scratch2, Register scratch3) {