Reviewers: mvstanton,
Message:
Hey Michael,
This is an obvious optimization for inline binary operations in crankshaft.
PTAL
-- Benedikt
Description:
Don't generate useless string checks for string adds.
If we know that one side of a string add is definitely a string
(i.e. if it's a string constant), then we don't need to emit a
string check for the argument.
This adds a new BuildCheckString() method to the graph builder,
which does "the right thing".
TEST=mjsunit/string-add
Please review this at https://codereview.chromium.org/78063002/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+19, -8 lines):
M src/hydrogen.h
M src/hydrogen.cc
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
22da9477e53608ce1b4df08357bfce25960e2e53..b47bb956630b35dfdb9457c9c80934440e9d21f4
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1273,6 +1273,20 @@ HValue* HGraphBuilder::BuildCheckMap(HValue* obj,
Handle<Map> map) {
}
+HValue* HGraphBuilder::BuildCheckString(
+ HValue* object, const char* failure_reason) {
+ if (!object->type().IsString()) {
+ ASSERT(!object->IsConstant() ||
+ !HConstant::cast(object)->HasStringValue());
+ IfBuilder if_isstring(this);
+ if_isstring.If<HIsStringAndBranch>(object);
+ if_isstring.Then();
+ if_isstring.ElseDeopt(failure_reason);
+ }
+ return object;
+}
+
+
HValue* HGraphBuilder::BuildWrapReceiver(HValue* object, HValue* function)
{
if (object->type().IsJSObject()) return object;
return Add<HWrapReceiver>(object, function);
@@ -8631,18 +8645,14 @@ HInstruction* HGraphBuilder::BuildBinaryOperation(
(left_type->Is(Type::String()) || right_type->Is(Type::String()))) {
// Validate type feedback for left argument.
if (left_type->Is(Type::String())) {
- IfBuilder if_isstring(this);
- if_isstring.If<HIsStringAndBranch>(left);
- if_isstring.Then();
- if_isstring.ElseDeopt("Expected string for LHS of binary operation");
+ left = BuildCheckString(
+ left, "Expected string for LHS of binary operation");
}
// Validate type feedback for right argument.
if (right_type->Is(Type::String())) {
- IfBuilder if_isstring(this);
- if_isstring.If<HIsStringAndBranch>(right);
- if_isstring.Then();
- if_isstring.ElseDeopt("Expected string for RHS of binary operation");
+ right = BuildCheckString(
+ right, "Expected string for RHS of binary operation");
}
// Convert left argument as necessary.
Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index
9aa9489aa3f376701f73aa5dc775714ae7d405f1..723bb440537f7ac1f1612057c70212b9c1a2b5ed
100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -1256,6 +1256,7 @@ class HGraphBuilder {
HValue* BuildCheckHeapObject(HValue* object);
HValue* BuildCheckMap(HValue* obj, Handle<Map> map);
+ HValue* BuildCheckString(HValue* object, const char* failure_reason);
HValue* BuildWrapReceiver(HValue* object, HValue* function);
// Building common constructs
--
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
---
You received this message because you are subscribed to the Google Groups "v8-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
