Handle all kind of arguments in the ToBooleanStub. While this is not very...

Handle all kind of arguments in the ToBooleanStub. While this is not very thrilling in itself, it is one of several steps to add type recording to this stub. Removed a duplicate check for null in the ARM stub and made a tiny simplification, removing a sub instruction.

As a side note, this change has some positive impact on the performace, e.g. imaging-darkroom is 8.3% faster and ws-ieee754conv is even 19.9% faster. No idea why the speedup is so big in some cases, but never look a gift horse in the mouth... ;-)
Review URL: http://codereview.chromium.org/7042004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -1616,12 +1616,36 @@ void CompareStub::Generate(MacroAssembler* masm) {
 // The stub returns zero for false, and a non-zero value for true.
 void ToBooleanStub::Generate(MacroAssembler* masm) {
   // This stub uses VFP3 instructions.
-  ASSERT(CpuFeatures::IsEnabled(VFP3));
+  CpuFeatures::Scope scope(VFP3);
 
   Label false_result;
   Label not_heap_number;
   Register scratch = r9.is(tos_) ? r7 : r9;
 
+  // undefined -> false
+  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
+  __ cmp(tos_, ip);
+  __ b(eq, &false_result);
+
+  // Boolean -> its value
+  __ LoadRoot(ip, Heap::kFalseValueRootIndex);
+  __ cmp(tos_, ip);
+  __ b(eq, &false_result);
+  __ LoadRoot(ip, Heap::kTrueValueRootIndex);
+  __ cmp(tos_, ip);
+  // "tos_" is a register and contains a non-zero value.  Hence we implicitly
+  // return true if the equal condition is satisfied.
+  __ Ret(eq);
+
+  // Smis: 0 -> false, all other -> true
+  __ tst(tos_, tos_);
+  __ b(eq, &false_result);
+  __ tst(tos_, Operand(kSmiTagMask));
+  // "tos_" is a register and contains a non-zero value.  Hence we implicitly
+  // return true if the not equal condition is satisfied.
+  __ Ret(eq);
+
+  // 'null' -> false
   __ LoadRoot(ip, Heap::kNullValueRootIndex);
   __ cmp(tos_, ip);
   __ b(eq, &false_result);
@@ -1631,9 +1655,7 @@ void ToBooleanStub::Generate(MacroAssembler* masm) {
   __ LoadRoot(ip, Heap::kHeapNumberMapRootIndex);
   __ cmp(scratch, ip);
   __ b(&not_heap_number, ne);
-
-  __ sub(ip, tos_, Operand(kHeapObjectTag));
-  __ vldr(d1, ip, HeapNumber::kValueOffset);
+  __ vldr(d1, FieldMemOperand(tos_, HeapNumber::kValueOffset));
   __ VFPCompareAndSetFlags(d1, 0.0);
   // "tos_" is a register, and contains a non zero value by default.
   // Hence we only need to overwrite "tos_" with zero to return false for
@@ -1644,12 +1666,6 @@ void ToBooleanStub::Generate(MacroAssembler* masm) {
 
   __ bind(&not_heap_number);
 
-  // Check if the value is 'null'.
-  // 'null' => false.
-  __ LoadRoot(ip, Heap::kNullValueRootIndex);
-  __ cmp(tos_, ip);
-  __ b(&false_result, eq);
-
   // It can be an undetectable object.
   // Undetectable => false.
   __ ldr(ip, FieldMemOperand(tos_, HeapObject::kMapOffset));

src/arm/full-codegen-arm.cc

@@ -562,23 +562,6 @@ void FullCodeGenerator::DoTest(Label* if_true,
                                Label* if_false,
                                Label* fall_through) {
   if (CpuFeatures::IsSupported(VFP3)) {
-    CpuFeatures::Scope scope(VFP3);
-    // Emit the inlined tests assumed by the stub.
-    __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
-    __ cmp(result_register(), ip);
-    __ b(eq, if_false);
-    __ LoadRoot(ip, Heap::kTrueValueRootIndex);
-    __ cmp(result_register(), ip);
-    __ b(eq, if_true);
-    __ LoadRoot(ip, Heap::kFalseValueRootIndex);
-    __ cmp(result_register(), ip);
-    __ b(eq, if_false);
-    STATIC_ASSERT(kSmiTag == 0);
-    __ tst(result_register(), result_register());
-    __ b(eq, if_false);
-    __ JumpIfSmi(result_register(), if_true);
-
-    // Call the ToBoolean stub for all other cases.
     ToBooleanStub stub(result_register());
     __ CallStub(&stub);
     __ tst(result_register(), result_register());
@@ -590,8 +573,6 @@ void FullCodeGenerator::DoTest(Label* if_true,
     __ LoadRoot(ip, Heap::kFalseValueRootIndex);
     __ cmp(r0, ip);
   }
-
-  // The stub returns nonzero for true.
   Split(ne, if_true, if_false, fall_through);
 }
 

src/ia32/code-stubs-ia32.cc

@@ -244,9 +244,25 @@ void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
 void ToBooleanStub::Generate(MacroAssembler* masm) {
   Label false_result, true_result, not_string;
   __ mov(eax, Operand(esp, 1 * kPointerSize));
+  Factory* factory = masm->isolate()->factory();
+
+  // undefined -> false
+  __ cmp(eax, factory->undefined_value());
+  __ j(equal, &false_result);
+
+  // Boolean -> its value
+  __ cmp(eax, factory->true_value());
+  __ j(equal, &true_result);
+  __ cmp(eax, factory->false_value());
+  __ j(equal, &false_result);
+
+  // Smis: 0 -> false, all other -> true
+  __ test(eax, Operand(eax));
+  __ j(zero, &false_result);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &true_result);
 
   // 'null' => false.
-  Factory* factory = masm->isolate()->factory();
   __ cmp(eax, factory->null_value());
   __ j(equal, &false_result, Label::kNear);
 

src/ia32/full-codegen-ia32.cc

@@ -548,25 +548,10 @@ void FullCodeGenerator::TestContext::Plug(bool flag) const {
 void FullCodeGenerator::DoTest(Label* if_true,
                                Label* if_false,
                                Label* fall_through) {
-  // Emit the inlined tests assumed by the stub.
-  __ cmp(result_register(), isolate()->factory()->undefined_value());
-  __ j(equal, if_false);
-  __ cmp(result_register(), isolate()->factory()->true_value());
-  __ j(equal, if_true);
-  __ cmp(result_register(), isolate()->factory()->false_value());
-  __ j(equal, if_false);
-  STATIC_ASSERT(kSmiTag == 0);
-  __ test(result_register(), Operand(result_register()));
-  __ j(zero, if_false);
-  __ test(result_register(), Immediate(kSmiTagMask));
-  __ j(zero, if_true);
-
-  // Call the ToBoolean stub for all other cases.
   ToBooleanStub stub;
   __ push(result_register());
   __ CallStub(&stub);
   __ test(eax, Operand(eax));
-
   // The stub returns nonzero for true.
   Split(not_zero, if_true, if_false, fall_through);
 }

src/x64/code-stubs-x64.cc

@@ -235,6 +235,22 @@ void ToBooleanStub::Generate(MacroAssembler* masm) {
   Label false_result, true_result, not_string;
   __ movq(rax, Operand(rsp, 1 * kPointerSize));
 
+  // undefined -> false
+  __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
+  __ j(equal, &false_result);
+
+  // Boolean -> its value
+  __ CompareRoot(rax, Heap::kFalseValueRootIndex);
+  __ j(equal, &false_result);
+  __ CompareRoot(rax, Heap::kTrueValueRootIndex);
+  __ j(equal, &true_result);
+
+  // Smis: 0 -> false, all other -> true
+  __ Cmp(rax, Smi::FromInt(0));
+  __ j(equal, &false_result);
+  Condition is_smi = __ CheckSmi(rax);
+  __ j(is_smi, &true_result);
+
   // 'null' => false.
   __ CompareRoot(rax, Heap::kNullValueRootIndex);
   __ j(equal, &false_result, Label::kNear);

src/x64/full-codegen-x64.cc

@@ -553,25 +553,10 @@ void FullCodeGenerator::TestContext::Plug(bool flag) const {
 void FullCodeGenerator::DoTest(Label* if_true,
                                Label* if_false,
                                Label* fall_through) {
-  // Emit the inlined tests assumed by the stub.
-  __ CompareRoot(result_register(), Heap::kUndefinedValueRootIndex);
-  __ j(equal, if_false);
-  __ CompareRoot(result_register(), Heap::kTrueValueRootIndex);
-  __ j(equal, if_true);
-  __ CompareRoot(result_register(), Heap::kFalseValueRootIndex);
-  __ j(equal, if_false);
-  STATIC_ASSERT(kSmiTag == 0);
-  __ Cmp(result_register(), Smi::FromInt(0));
-  __ j(equal, if_false);
-  Condition is_smi = masm_->CheckSmi(result_register());
-  __ j(is_smi, if_true);
-
-  // Call the ToBoolean stub for all other cases.
   ToBooleanStub stub;
   __ push(result_register());
   __ CallStub(&stub);
   __ testq(rax, rax);
-
   // The stub returns nonzero for true.
   Split(not_zero, if_true, if_false, fall_through);
 }