Changeset 207060 in webkit

Timestamp:

Oct 11, 2016 12:28:08 AM (8 years ago)

Author:

sbarati@apple.com

Message:

ValueAdd should be constant folded if the operands are constant String,Primitive or Primitive,String
​https://bugs.webkit.org/show_bug.cgi?id=163182

Reviewed by Filip Pizlo.

JSTests:

• microbenchmarks/string-add-constant-folding.js: Added.

(assert):
(runTests):
(add):
(test):

Source/JavaScriptCore:

This code pattern shows up in Dromaeo, so it's worth optimizing for.
This might also show up in real world JS code due to inlining and other
types of constant folding.

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::parseBlock):

• dfg/DFGLazyJSValue.cpp:

(JSC::DFG::LazyJSValue::getValue):

• dfg/DFGStrengthReductionPhase.cpp:

(JSC::DFG::StrengthReductionPhase::handleNode):

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/microbenchmarks/string-add-constant-folding.js (added)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp (modified) (1 diff)
• Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp (modified) (1 diff)
• Source/JavaScriptCore/dfg/DFGStrengthReductionPhase.cpp (modified) (1 diff)

trunk/JSTests/ChangeLog

@@ +1 @@
+2016-10-11  Saam Barati  <sbarati@apple.com>
+
+        ValueAdd should be constant folded if the operands are constant String,Primitive or Primitive,String
+        https://bugs.webkit.org/show_bug.cgi?id=163182
+
+        Reviewed by Filip Pizlo.
+
+        * microbenchmarks/string-add-constant-folding.js: Added.
+        (assert):
+        (runTests):
+        (add):
+        (test):
+
 2016-10-07  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-10-11  Saam Barati  <sbarati@apple.com>
+
+        ValueAdd should be constant folded if the operands are constant String,Primitive or Primitive,String
+        https://bugs.webkit.org/show_bug.cgi?id=163182
+
+        Reviewed by Filip Pizlo.
+
+        This code pattern shows up in Dromaeo, so it's worth optimizing for.
+        This might also show up in real world JS code due to inlining and other
+        types of constant folding.
+
+        * dfg/DFGByteCodeParser.cpp:
+        (JSC::DFG::ByteCodeParser::parseBlock):
+        * dfg/DFGLazyJSValue.cpp:
+        (JSC::DFG::LazyJSValue::getValue):
+        * dfg/DFGStrengthReductionPhase.cpp:
+        (JSC::DFG::StrengthReductionPhase::handleNode):
+
 2016-10-10  Zan Dobersek  <zdobersek@igalia.com>
 

trunk/Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp

@@ -4240 +4240 @@
                 // FIXME: When the bytecode is not compiled in the baseline JIT, byValInfo becomes null.
                 // At that time, there is no information.
-                if (byValInfo && byValInfo->stubInfo && !byValInfo->tookSlowPath && !m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadIdent) && !m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadCell)) {
+                if (byValInfo 
+                    && byValInfo->stubInfo
+                    && !byValInfo->tookSlowPath
+                    && !m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadIdent)
+                    && !m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadType)
+                    && !m_inlineStackTop->m_exitProfile.hasExitSite(m_currentIndex, BadCell)) {
                     compiledAsPutById = true;
                     unsigned identifierNumber = m_graph.identifiers().ensure(byValInfo->cachedId.impl());

trunk/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp

@@ -52 +52 @@
         return jsSingleCharacterString(&vm, u.character);
     case KnownStringImpl:
-    case NewStringImpl:
         return jsString(&vm, u.stringImpl);
+    case NewStringImpl:
+        return jsString(&vm, AtomicStringImpl::add(u.stringImpl));
     }
     RELEASE_ASSERT_NOT_REACHED();

trunk/Source/JavaScriptCore/dfg/DFGStrengthReductionPhase.cpp

@@ -323 +323 @@
         // https://bugs.webkit.org/show_bug.cgi?id=155204
 
+        case ValueAdd: {
+            if (m_node->child1()->isConstant()
+                && m_node->child2()->isConstant()
+                && (!!m_node->child1()->tryGetString(m_graph) || !!m_node->child2()->tryGetString(m_graph))) {
+                auto tryGetConstantString = [&] (Node* node) -> String {
+                    String string = node->tryGetString(m_graph);
+                    if (!string.isEmpty())
+                        return string;
+                    JSValue value = node->constant()->value();
+                    if (!value)
+                        return String();
+                    if (value.isInt32())
+                        return String::number(value.asInt32());
+                    if (value.isNumber())
+                        return String::numberToStringECMAScript(value.asNumber());
+                    if (value.isBoolean())
+                        return value.asBoolean() ? ASCIILiteral("true") : ASCIILiteral("false");
+                    if (value.isNull())
+                        return ASCIILiteral("null");
+                    if (value.isUndefined())
+                        return ASCIILiteral("undefined");
+                    return String();
+                };
+
+                String leftString = tryGetConstantString(m_node->child1().node());
+                if (!leftString)
+                    break;
+                String rightString = tryGetConstantString(m_node->child2().node());
+                if (!rightString)
+                    break;
+
+                StringBuilder builder;
+                builder.append(leftString);
+                builder.append(rightString);
+                m_node->convertToLazyJSConstant(
+                    m_graph, LazyJSValue::newString(m_graph, builder.toString()));
+                m_changed = true;
+            }
+            break;
+        }
+
         case MakeRope:
-        case ValueAdd:
         case StrCat: {
             String leftString = m_node->child1()->tryGetString(m_graph);