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[compiler] Reduce the code size of the ToBoolean stub.

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We effectively have 4 different cases to deal with, including the default, but on some platform where we emit the jump table inline (e.g. arm64) we end up emitting an unconditional jump to the same address 127 times.

BUG=

Review-Url: https://codereview.chromium.org/1765883002
Cr-Commit-Position: refs/heads/master@{#35859}
This commit is contained in:
epertoso 2016-04-28 05:21:54 -07:00 committed by Commit bot
parent 9e16f72a63
commit 914c6c52a5
1 changed files with 26 additions and 55 deletions
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81
src/code-stubs.cc
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@ -3549,7 +3549,8 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
typedef CodeStubAssembler::Label Label;
Node* value = assembler->Parameter(0);
Label if_valueissmi(assembler), if_valueisnotsmi(assembler);
Label if_valueissmi(assembler), if_valueisnotsmi(assembler),
return_true(assembler), return_false(assembler);
// Check if {value} is a Smi or a HeapObject.
assembler->Branch(assembler->WordIsSmi(value), &if_valueissmi,
@ -3558,21 +3559,15 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
assembler->Bind(&if_valueissmi);
{
// The {value} is a Smi, only need to check against zero.
Label if_valueiszero(assembler), if_valueisnotzero(assembler);
assembler->Branch(assembler->SmiEqual(value, assembler->SmiConstant(0)),
&if_valueiszero, &if_valueisnotzero);
assembler->Bind(&if_valueiszero);
assembler->Return(assembler->BooleanConstant(false));
assembler->Bind(&if_valueisnotzero);
assembler->Return(assembler->BooleanConstant(true));
&return_false, &return_true);
}
assembler->Bind(&if_valueisnotsmi);
{
Label if_valueisstring(assembler), if_valueisheapnumber(assembler),
if_valueisoddball(assembler), if_valueisother(assembler);
Label if_valueisstring(assembler), if_valueisnotstring(assembler),
if_valueisheapnumber(assembler), if_valueisoddball(assembler),
if_valueisother(assembler);
// The {value} is a HeapObject, load its map.
Node* value_map = assembler->LoadMap(value);
@ -3584,24 +3579,20 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
// Dispatch based on the instance type; we distinguish all String instance
// types, the HeapNumber type and the Oddball type.
size_t const kNumCases = FIRST_NONSTRING_TYPE + 2;
assembler->Branch(assembler->Int32LessThan(
value_instance_type,
assembler->Int32Constant(FIRST_NONSTRING_TYPE)),
&if_valueisstring, &if_valueisnotstring);
assembler->Bind(&if_valueisnotstring);
size_t const kNumCases = 2;
Label* case_labels[kNumCases];
int32_t case_values[kNumCases];
for (int32_t i = 0; i < FIRST_NONSTRING_TYPE; ++i) {
case_labels[i] = new Label(assembler);
case_values[i] = i;
}
case_labels[FIRST_NONSTRING_TYPE + 0] = &if_valueisheapnumber;
case_values[FIRST_NONSTRING_TYPE + 0] = HEAP_NUMBER_TYPE;
case_labels[FIRST_NONSTRING_TYPE + 1] = &if_valueisoddball;
case_values[FIRST_NONSTRING_TYPE + 1] = ODDBALL_TYPE;
case_labels[0] = &if_valueisheapnumber;
case_values[0] = HEAP_NUMBER_TYPE;
case_labels[1] = &if_valueisoddball;
case_values[1] = ODDBALL_TYPE;
assembler->Switch(value_instance_type, &if_valueisother, case_values,
case_labels, arraysize(case_values));
for (int32_t i = 0; i < FIRST_NONSTRING_TYPE; ++i) {
assembler->Bind(case_labels[i]);
assembler->Goto(&if_valueisstring);
delete case_labels[i];
}
assembler->Bind(&if_valueisstring);
{
@ -3610,16 +3601,9 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
assembler->LoadObjectField(value, String::kLengthOffset);
// Check if the {value} is the empty string.
Label if_valueisempty(assembler), if_valueisnotempty(assembler);
assembler->Branch(
assembler->SmiEqual(value_length, assembler->SmiConstant(0)),
&if_valueisempty, &if_valueisnotempty);
assembler->Bind(&if_valueisempty);
assembler->Return(assembler->BooleanConstant(false));
assembler->Bind(&if_valueisnotempty);
assembler->Return(assembler->BooleanConstant(true));
&return_false, &return_true);
}
assembler->Bind(&if_valueisheapnumber);
@ -3628,25 +3612,15 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
MachineType::Float64(), value,
assembler->IntPtrConstant(HeapNumber::kValueOffset - kHeapObjectTag));
Label if_valueispositive(assembler), if_valueisnotpositive(assembler),
if_valueisnegative(assembler), if_valueisnanorzero(assembler);
Label if_valueisnotpositive(assembler);
assembler->Branch(assembler->Float64LessThan(
assembler->Float64Constant(0.0), value_value),
&if_valueispositive, &if_valueisnotpositive);
assembler->Bind(&if_valueispositive);
assembler->Return(assembler->BooleanConstant(true));
&return_true, &if_valueisnotpositive);
assembler->Bind(&if_valueisnotpositive);
assembler->Branch(assembler->Float64LessThan(
value_value, assembler->Float64Constant(0.0)),
&if_valueisnegative, &if_valueisnanorzero);
assembler->Bind(&if_valueisnegative);
assembler->Return(assembler->BooleanConstant(true));
assembler->Bind(&if_valueisnanorzero);
assembler->Return(assembler->BooleanConstant(false));
&return_true, &return_false);
}
assembler->Bind(&if_valueisoddball);
@ -3667,19 +3641,16 @@ void ToBooleanStub::GenerateAssembly(CodeStubAssembler* assembler) const {
assembler->Int32Constant(1 << Map::kIsUndetectable));
// Check if the {value} is undetectable.
Label if_valueisundetectable(assembler),
if_valueisnotundetectable(assembler);
assembler->Branch(assembler->Word32Equal(value_map_undetectable,
assembler->Int32Constant(0)),
&if_valueisnotundetectable, &if_valueisundetectable);
assembler->Bind(&if_valueisundetectable);
assembler->Return(assembler->BooleanConstant(false));
assembler->Bind(&if_valueisnotundetectable);
assembler->Return(assembler->BooleanConstant(true));
&return_true, &return_false);
}
}
assembler->Bind(&return_false);
assembler->Return(assembler->BooleanConstant(false));
assembler->Bind(&return_true);
assembler->Return(assembler->BooleanConstant(true));
}
void ToIntegerStub::GenerateAssembly(CodeStubAssembler* assembler) const {