Author: olehougaard
Date: Wed Feb 25 23:54:22 2009
New Revision: 1372
Added:
branches/bleeding_edge/test/mjsunit/top-level-assignments.js
Modified:
branches/bleeding_edge/src/ast.h
branches/bleeding_edge/src/codegen-ia32.cc
branches/bleeding_edge/src/parser.cc
branches/bleeding_edge/src/runtime.cc
branches/bleeding_edge/src/runtime.h
Log:
Go into slow case when encountering object initialization on the top level
to optimize performance of code like
C.prototype.x = ...;
C.prototype.y = ...;
...
C.prototype.z = ...;
Review URL: http://codereview.chromium.org/27128
Modified: branches/bleeding_edge/src/ast.h
==============================================================================
--- branches/bleeding_edge/src/ast.h (original)
+++ branches/bleeding_edge/src/ast.h Wed Feb 25 23:54:22 2009
@@ -1106,7 +1106,8 @@
class Assignment: public Expression {
public:
Assignment(Token::Value op, Expression* target, Expression* value, int
pos)
- : op_(op), target_(target), value_(value), pos_(pos) {
+ : op_(op), target_(target), value_(value), pos_(pos),
+ block_start_(false), block_end_(false) {
ASSERT(Token::IsAssignmentOp(op));
}
@@ -1120,11 +1121,22 @@
Expression* value() const { return value_; }
int position() { return pos_; }
+ // An initialization block is a series of statments of the form
+ // x.y.z.a = ...; x.y.z.b = ...; etc. The parser marks the beginning and
+ // ending of these blocks to allow for optimizations of initialization
+ // blocks.
+ bool starts_initialization_block() { return block_start_; }
+ bool ends_initialization_block() { return block_end_; }
+ void mark_block_start() { block_start_ = true; }
+ void mark_block_end() { block_end_ = true; }
+
private:
Token::Value op_;
Expression* target_;
Expression* value_;
int pos_;
+ bool block_start_;
+ bool block_end_;
};
Modified: branches/bleeding_edge/src/codegen-ia32.cc
==============================================================================
--- branches/bleeding_edge/src/codegen-ia32.cc (original)
+++ branches/bleeding_edge/src/codegen-ia32.cc Wed Feb 25 23:54:22 2009
@@ -2758,6 +2758,15 @@
Reference target(this, node->target());
if (target.is_illegal()) return;
+ if (node->starts_initialization_block()) {
+ ASSERT(target.type() == Reference::NAMED ||
+ target.type() == Reference::KEYED);
+ // Change to slow case in the beginning of an initialization block
+ // to avoid the quadratic behavior of repeatedly adding fast
properties.
+ int stack_position = (target.type() == Reference::NAMED) ? 0 : 1;
+ frame_->Push(Operand(esp, stack_position * kPointerSize));
+ __ CallRuntime(Runtime::kToSlowProperties, 1);
+ }
if (node->op() == Token::ASSIGN ||
node->op() == Token::INIT_VAR ||
node->op() == Token::INIT_CONST) {
@@ -2789,6 +2798,14 @@
target.SetValue(CONST_INIT);
} else {
target.SetValue(NOT_CONST_INIT);
+ if (node->ends_initialization_block()) {
+ ASSERT(target.type() == Reference::NAMED ||
+ target.type() == Reference::KEYED);
+ // End of initialization block. Revert to fast case.
+ int stack_position = (target.type() == Reference::NAMED) ? 1 : 2;
+ frame_->Push(Operand(esp, stack_position * kPointerSize));
+ __ CallRuntime(Runtime::kToFastProperties, 1);
+ }
}
}
}
Modified: branches/bleeding_edge/src/parser.cc
==============================================================================
--- branches/bleeding_edge/src/parser.cc (original)
+++ branches/bleeding_edge/src/parser.cc Wed Feb 25 23:54:22 2009
@@ -69,6 +69,11 @@
Handle<String> name,
int start_position, bool is_expression);
+ // The minimum number of contiguous assignment that will
+ // be treated as an initialization block. Benchmarks show that
+ // the overhead exceeds the savings below this limit.
+ static const int kMinInitializationBlock = 3;
+
protected:
enum Mode {
@@ -1215,6 +1220,110 @@
}
+// An InitializationBlockFinder finds and marks sequences of statements of
the
+// form x.y.z.a = ...; x.y.z.b = ...; etc.
+class InitializationBlockFinder {
+ public:
+ InitializationBlockFinder()
+ : first_in_block_(NULL), last_in_block_(NULL), block_size_(0) {}
+
+ ~InitializationBlockFinder() {
+ if (InBlock()) EndBlock();
+ }
+
+ void Update(Statement* stat) {
+ Assignment* assignment = AsAssignment(stat);
+ if (InBlock()) {
+ if (BlockContinues(assignment)) {
+ UpdateBlock(assignment);
+ } else {
+ EndBlock();
+ }
+ }
+ if (!InBlock() && (assignment != NULL) &&
+ (assignment->op() == Token::ASSIGN)) {
+ StartBlock(assignment);
+ }
+ }
+
+ private:
+ static Assignment* AsAssignment(Statement* stat) {
+ if (stat == NULL) return NULL;
+ ExpressionStatement* exp_stat = stat->AsExpressionStatement();
+ if (exp_stat == NULL) return NULL;
+ return exp_stat->expression()->AsAssignment();
+ }
+
+ // Returns true if the expressions appear to denote the same object.
+ // In the context of initialization blocks, we only consider expressions
+ // of the form 'x.y.z'.
+ static bool SameObject(Expression* e1, Expression* e2) {
+ VariableProxy* v1 = e1->AsVariableProxy();
+ VariableProxy* v2 = e2->AsVariableProxy();
+ if (v1 != NULL && v2 != NULL) {
+ return v1->name()->Equals(*v2->name());
+ }
+ Property* p1 = e1->AsProperty();
+ Property* p2 = e2->AsProperty();
+ if ((p1 == NULL) || (p2 == NULL)) return false;
+ Literal* key1 = p1->key()->AsLiteral();
+ Literal* key2 = p2->key()->AsLiteral();
+ if ((key1 == NULL) || (key2 == NULL)) return false;
+ if (!key1->handle()->IsString() || !key2->handle()->IsString()) {
+ return false;
+ }
+ String* name1 = String::cast(*key1->handle());
+ String* name2 = String::cast(*key2->handle());
+ if (!name1->Equals(name2)) return false;
+ return SameObject(p1->obj(), p2->obj());
+ }
+
+ // Returns true if the expressions appear to denote different properties
+ // of the same object.
+ static bool PropertyOfSameObject(Expression* e1, Expression* e2) {
+ Property* p1 = e1->AsProperty();
+ Property* p2 = e2->AsProperty();
+ if ((p1 == NULL) || (p2 == NULL)) return false;
+ return SameObject(p1->obj(), p2->obj());
+ }
+
+ bool BlockContinues(Assignment* assignment) {
+ if ((assignment == NULL) || (first_in_block_ == NULL)) return false;
+ if (assignment->op() != Token::ASSIGN) return false;
+ return PropertyOfSameObject(first_in_block_->target(),
+ assignment->target());
+ }
+
+ void StartBlock(Assignment* assignment) {
+ first_in_block_ = assignment;
+ last_in_block_ = assignment;
+ block_size_ = 1;
+ }
+
+ void UpdateBlock(Assignment* assignment) {
+ last_in_block_ = assignment;
+ ++block_size_;
+ }
+
+ void EndBlock() {
+ if (block_size_ >= Parser::kMinInitializationBlock) {
+ first_in_block_->mark_block_start();
+ last_in_block_->mark_block_end();
+ }
+ last_in_block_ = first_in_block_ = NULL;
+ block_size_ = 0;
+ }
+
+ bool InBlock() { return first_in_block_ != NULL; }
+
+ Assignment* first_in_block_;
+ Assignment* last_in_block_;
+ int block_size_;
+
+ DISALLOW_COPY_AND_ASSIGN(InitializationBlockFinder);
+};
+
+
void* Parser::ParseSourceElements(ZoneListWrapper<Statement>* processor,
int end_token,
bool* ok) {
@@ -1228,9 +1337,15 @@
TargetScope scope(this);
ASSERT(processor != NULL);
+ InitializationBlockFinder block_finder;
while (peek() != end_token) {
Statement* stat = ParseStatement(NULL, CHECK_OK);
- if (stat && !stat->IsEmpty()) processor->Add(stat);
+ if (stat == NULL || stat->IsEmpty()) continue;
+ // We find and mark the initialization blocks on top level code only.
+ // This is because the optimization prevents reuse of the map
transitions,
+ // so it should be used only for code that will only be run once.
+ if (top_scope_->is_global_scope()) block_finder.Update(stat);
+ processor->Add(stat);
}
return 0;
}
Modified: branches/bleeding_edge/src/runtime.cc
==============================================================================
--- branches/bleeding_edge/src/runtime.cc (original)
+++ branches/bleeding_edge/src/runtime.cc Wed Feb 25 23:54:22 2009
@@ -2151,6 +2151,22 @@
}
+static Object* Runtime_ToFastProperties(Arguments args) {
+ ASSERT(args.length() == 1);
+ CONVERT_ARG_CHECKED(JSObject, object, 0);
+ object->TransformToFastProperties(0);
+ return *object;
+}
+
+
+static Object* Runtime_ToSlowProperties(Arguments args) {
+ ASSERT(args.length() == 1);
+ CONVERT_ARG_CHECKED(JSObject, object, 0);
+ object->NormalizeProperties(CLEAR_INOBJECT_PROPERTIES);
+ return *object;
+}
+
+
static Object* Runtime_ToBool(Arguments args) {
NoHandleAllocation ha;
ASSERT(args.length() == 1);
Modified: branches/bleeding_edge/src/runtime.h
==============================================================================
--- branches/bleeding_edge/src/runtime.h (original)
+++ branches/bleeding_edge/src/runtime.h Wed Feb 25 23:54:22 2009
@@ -49,6 +49,8 @@
F(GetPropertyNames, 1) \
F(GetPropertyNamesFast, 1) \
F(GetArgumentsProperty, 1) \
+ F(ToFastProperties, 1) \
+ F(ToSlowProperties, 1) \
\
F(IsInPrototypeChain, 2) \
\
Added: branches/bleeding_edge/test/mjsunit/top-level-assignments.js
==============================================================================
--- (empty file)
+++ branches/bleeding_edge/test/mjsunit/top-level-assignments.js Wed Feb
25
23:54:22 2009
@@ -0,0 +1,96 @@
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Testing that optimization of top-level object initialization doesn't
+// break V8.
+
+var x = new Object();
+x.a = 7;
+x.b = function() { return 42; };
+x.c = 88;
+x.d = "A Man Called Horse";
+
+assertEquals(7, x.a);
+assertEquals(42, x.b());
+assertEquals(88, x.c);
+assertEquals("A Man Called Horse", x.d);
+
+var y = new Object();
+y.a = 7;
+y.b = function() { return 42; };
+y.c = 12 * y.a;
+y.d = "A Man Called Horse";
+
+assertEquals(84, y.c);
+
+var z = new Object();
+z.a = 3;
+function forty_two() { return 42; };
+z.a += 4;
+z.b = forty_two;
+z.c = 12;
+z.c *= z.a;
+z.d = "A Man Called Horse";
+
+assertEquals(84, z.c);
+
+var x1 = new Object();
+var x2 = new Object();
+x1.a = 7;
+x1.b = function() { return 42; };
+x2.a = 7;
+x2.b = function() { return 42; };
+x1.c = 88;
+x1.d = "A Man Called Horse";
+x2.c = 88;
+x2.d = "A Man Called Horse";
+
+assertEquals(7, x1.a);
+assertEquals(42, x1.b());
+assertEquals(88, x1.c);
+assertEquals("A Man Called Horse", x1.d);
+
+assertEquals(7, x2.a);
+assertEquals(42, x2.b());
+assertEquals(88, x2.c);
+assertEquals("A Man Called Horse", x2.d);
+
+function Calculator(x, y) {
+ this.x = x;
+ this.y = y;
+}
+
+Calculator.prototype.sum = function() { return this.x + this.y; };
+Calculator.prototype.difference = function() { return this.x - this.y; };
+Calculator.prototype.product = function() { return this.x * this.y; };
+Calculator.prototype.quotient = function() { return this.x / this.y; };
+
+var calc = new Calculator(20, 10);
+assertEquals(30, calc.sum());
+assertEquals(10, calc.difference());
+assertEquals(200, calc.product());
+assertEquals(2, calc.quotient());
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