Commit d75b34db authored by olivf@chromium.org's avatar olivf@chromium.org

There is no undefined Literal.

BUG=
R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/18429005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15724 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
parent 22f2fd83
......@@ -71,8 +71,14 @@ bool Expression::IsNullLiteral() {
}
bool Expression::IsUndefinedLiteral() {
return AsLiteral() != NULL && AsLiteral()->value()->IsUndefined();
bool Expression::IsUndefinedLiteral(Isolate* isolate) {
VariableProxy* var_proxy = AsVariableProxy();
if (var_proxy == NULL) return false;
Variable* var = var_proxy->var();
// The global identifier "undefined" is immutable. Everything
// else could be reassigned.
return var != NULL && var->location() == Variable::UNALLOCATED &&
var_proxy->name()->Equals(isolate->heap()->undefined_string());
}
......@@ -385,12 +391,13 @@ static bool IsVoidOfLiteral(Expression* expr) {
static bool MatchLiteralCompareUndefined(Expression* left,
Token::Value op,
Expression* right,
Expression** expr) {
Expression** expr,
Isolate* isolate) {
if (IsVoidOfLiteral(left) && Token::IsEqualityOp(op)) {
*expr = right;
return true;
}
if (left->IsUndefinedLiteral() && Token::IsEqualityOp(op)) {
if (left->IsUndefinedLiteral(isolate) && Token::IsEqualityOp(op)) {
*expr = right;
return true;
}
......@@ -398,9 +405,10 @@ static bool MatchLiteralCompareUndefined(Expression* left,
}
bool CompareOperation::IsLiteralCompareUndefined(Expression** expr) {
return MatchLiteralCompareUndefined(left_, op_, right_, expr) ||
MatchLiteralCompareUndefined(right_, op_, left_, expr);
bool CompareOperation::IsLiteralCompareUndefined(
Expression** expr, Isolate* isolate) {
return MatchLiteralCompareUndefined(left_, op_, right_, expr, isolate) ||
MatchLiteralCompareUndefined(right_, op_, left_, expr, isolate);
}
......
......@@ -353,8 +353,8 @@ class Expression: public AstNode {
// True iff the expression is the null literal.
bool IsNullLiteral();
// True iff the expression is the undefined literal.
bool IsUndefinedLiteral();
// True if we can prove that the expression is the undefined literal.
bool IsUndefinedLiteral(Isolate* isolate);
// Expression type bounds
Bounds bounds() { return bounds_; }
......@@ -1994,7 +1994,7 @@ class CompareOperation: public Expression {
// Match special cases.
bool IsLiteralCompareTypeof(Expression** expr, Handle<String>* check);
bool IsLiteralCompareUndefined(Expression** expr);
bool IsLiteralCompareUndefined(Expression** expr, Isolate* isolate);
bool IsLiteralCompareNull(Expression** expr);
protected:
......
......@@ -1605,7 +1605,7 @@ bool FullCodeGenerator::TryLiteralCompare(CompareOperation* expr) {
return true;
}
if (expr->IsLiteralCompareUndefined(&sub_expr)) {
if (expr->IsLiteralCompareUndefined(&sub_expr, isolate())) {
EmitLiteralCompareNil(expr, sub_expr, kUndefinedValue);
return true;
}
......
......@@ -8164,7 +8164,7 @@ void HOptimizedGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
if (expr->IsLiteralCompareTypeof(&sub_expr, &check)) {
return HandleLiteralCompareTypeof(expr, sub_expr, check);
}
if (expr->IsLiteralCompareUndefined(&sub_expr)) {
if (expr->IsLiteralCompareUndefined(&sub_expr, isolate())) {
return HandleLiteralCompareNil(expr, sub_expr, kUndefinedValue);
}
if (expr->IsLiteralCompareNull(&sub_expr)) {
......
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