Changeset 89058 in webkit

Timestamp:

Jun 16, 2011 12:30:57 PM (13 years ago)

Author:

oliver@apple.com

Message:

2011-06-15 Oliver Hunt <​oliver@apple.com>

Reviewed by Geoffrey Garen.

Reduce memory usage of resolve_global
​https://bugs.webkit.org/show_bug.cgi?id=62765

If we have a large number of resolve_globals in a single
block start planting plain resolve instructions instead
whenever we aren't in a loop. This allows us to reduce
the code size for extremely large functions without
losing the performance benefits of op_resolve_global.

• bytecode/CodeBlock.h: (JSC::CodeBlock::globalResolveInfoCount):
• bytecompiler/BytecodeGenerator.cpp: (JSC::BytecodeGenerator::shouldAvoidResolveGlobal): (JSC::BytecodeGenerator::emitResolve): (JSC::BytecodeGenerator::emitResolveWithBase):
• bytecompiler/BytecodeGenerator.h:

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• bytecode/CodeBlock.h (modified) (1 diff)
• bytecompiler/BytecodeGenerator.cpp (modified) (3 diffs)
• bytecompiler/BytecodeGenerator.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-06-15  Oliver Hunt  <oliver@apple.com>
+
+        Reviewed by Geoffrey Garen.
+
+        Reduce memory usage of resolve_global
+        https://bugs.webkit.org/show_bug.cgi?id=62765
+
+        If we have a large number of resolve_globals in a single
+        block start planting plain resolve instructions instead 
+        whenever we aren't in a loop.  This allows us to reduce
+        the code size for extremely large functions without
+        losing the performance benefits of op_resolve_global.
+
+        * bytecode/CodeBlock.h:
+        (JSC::CodeBlock::globalResolveInfoCount):
+        * bytecompiler/BytecodeGenerator.cpp:
+        (JSC::BytecodeGenerator::shouldAvoidResolveGlobal):
+        (JSC::BytecodeGenerator::emitResolve):
+        (JSC::BytecodeGenerator::emitResolveWithBase):
+        * bytecompiler/BytecodeGenerator.h:
+
 2011-06-16  Qi Zhang  <qi.2.zhang@nokia.com>
 

trunk/Source/JavaScriptCore/bytecode/CodeBlock.h

@@ -373 +373 @@
         MethodCallLinkInfo& methodCallLinkInfo(int index) { return m_methodCallLinkInfos[index]; }
 #endif
+        unsigned globalResolveInfoCount() const
+        {
+#if ENABLE(JIT)    
+            if (m_globalData->canUseJIT())
+                return m_globalResolveInfos.size();
+#endif
+            return 0;
+        }
 
         // Exception handling support

trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

@@ -1202 +1202 @@
 }
 
+static const unsigned maxGlobalResolves = 128;
+
+bool BytecodeGenerator::shouldAvoidResolveGlobal()
+{
+    return m_codeBlock->globalResolveInfoCount() > maxGlobalResolves && !m_labelScopes.size();
+}
+
 RegisterID* BytecodeGenerator::emitResolve(RegisterID* dst, const Identifier& property)
 {
@@ -1215 +1222 @@
         return dst;
     }
-
+    if (shouldAvoidResolveGlobal()) {
+        globalObject = 0;
+        requiresDynamicChecks = true;
+    }
+        
     if (globalObject) {
         bool forceGlobalResolve = false;
@@ -1364 +1375 @@
         return baseDst;
     }
-
+    if (shouldAvoidResolveGlobal()) {
+        emitOpcode(op_resolve);
+        instructions().append(propDst->index());
+        instructions().append(addConstant(property));
+        return baseDst;
+    }
 #if ENABLE(JIT)
     m_codeBlock->addGlobalResolveInfo(instructions().size());

trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h

@@ -460 +460 @@
         
         void preserveLastVar();
+        bool shouldAvoidResolveGlobal();
 
         RegisterID& registerFor(int index)