Changeset 145578 in webkit

Timestamp:

Mar 12, 2013 1:38:26 PM (11 years ago)

Author:

fpizlo@apple.com

Message:

DFG generic array access cases should not be guarded by CheckStructure even of the profiling tells us that it could be
​https://bugs.webkit.org/show_bug.cgi?id=112183

Reviewed by Oliver Hunt.

Slight speed-up on string-unpack-code.

• dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::findAndRemoveUnnecessaryStructureCheck):
(FixupPhase):
(JSC::DFG::FixupPhase::checkArray):
(JSC::DFG::FixupPhase::blessArrayOperation):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• dfg/DFGFixupPhase.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2013-03-12  Filip Pizlo  <fpizlo@apple.com>
+
+        DFG generic array access cases should not be guarded by CheckStructure even of the profiling tells us that it could be
+        https://bugs.webkit.org/show_bug.cgi?id=112183
+
+        Reviewed by Oliver Hunt.
+        
+        Slight speed-up on string-unpack-code.
+
+        * dfg/DFGFixupPhase.cpp:
+        (JSC::DFG::FixupPhase::findAndRemoveUnnecessaryStructureCheck):
+        (FixupPhase):
+        (JSC::DFG::FixupPhase::checkArray):
+        (JSC::DFG::FixupPhase::blessArrayOperation):
+
 2013-03-12  Gabor Rapcsanyi  <rgabor@webkit.org>
 

trunk/Source/JavaScriptCore/dfg/DFGFixupPhase.cpp

@@ -839 +839 @@
     }
     
-    Node* checkArray(ArrayMode arrayMode, CodeOrigin codeOrigin, Node* array, Node* index, bool (*storageCheck)(const ArrayMode&) = canCSEStorage)
+    void findAndRemoveUnnecessaryStructureCheck(Node* array, const CodeOrigin& codeOrigin)
+    {
+        for (unsigned index = m_indexInBlock; index--;) {
+            Node* previousNode = m_block->at(index);
+            if (previousNode->codeOrigin != codeOrigin)
+                return;
+            
+            if (previousNode->op() != CheckStructure)
+                continue;
+            
+            if (previousNode->child1() != array)
+                continue;
+            
+            previousNode->child1() = Edge();
+            previousNode->convertToPhantom();
+            return; // Assume we were smart enough to only insert one CheckStructure on the array.
+        }
+    }
+    
+    Node* checkArray(ArrayMode arrayMode, const CodeOrigin& codeOrigin, Node* array, Node* index, bool (*storageCheck)(const ArrayMode&) = canCSEStorage)
     {
         ASSERT(arrayMode.isSpecific());
@@ -851 +870 @@
                 if (m_indexInBlock > 0) {
                     // If the previous node was a CheckStructure inserted because of stuff
-                    // that the array profile told us, then remove it.
-                    Node* previousNode = m_block->at(m_indexInBlock - 1);
-                    if (previousNode->op() == CheckStructure
-                        && previousNode->child1() == array
-                        && previousNode->codeOrigin == codeOrigin)
-                        previousNode->convertToPhantom();
+                    // that the array profile told us, then remove it, since we're going to be
+                    // doing arrayification instead.
+                    findAndRemoveUnnecessaryStructureCheck(array, codeOrigin);
                 }
                 
@@ -909 +925 @@
             
         case Array::Generic:
+            findAndRemoveUnnecessaryStructureCheck(base.node(), node->codeOrigin);
             return;