Changeset 103292 in webkit for trunk/Source/JavaScriptCore

Timestamp:

Dec 19, 2011, 6:42:06 PM (13 years ago)

Author:

[email protected]

Message:

If we detect that we can use the JIT, don't use computed opcode lookups
​https://bugs.webkit.org/show_bug.cgi?id=74899
<rdar://problem/10604551>

Reviewed by Gavin Barraclough.

• interpreter/Interpreter.cpp:

(JSC::Interpreter::Interpreter):
(JSC::Interpreter::initialize):
(JSC::Interpreter::privateExecute):

• interpreter/Interpreter.h:

(JSC::Interpreter::getOpcode):
(JSC::Interpreter::getOpcodeID):

• runtime/JSGlobalData.cpp:

(JSC::JSGlobalData::JSGlobalData):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• interpreter/Interpreter.cpp (modified) (2 diffs)
• interpreter/Interpreter.h (modified) (3 diffs)
• runtime/JSGlobalData.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-12-19  Filip Pizlo  <[email protected]>
+
+        If we detect that we can use the JIT, don't use computed opcode lookups
+        https://bugs.webkit.org/show_bug.cgi?id=74899
+        <rdar://problem/10604551>
+
+        Reviewed by Gavin Barraclough.
+
+        * interpreter/Interpreter.cpp:
+        (JSC::Interpreter::Interpreter):
+        (JSC::Interpreter::initialize):
+        (JSC::Interpreter::privateExecute):
+        * interpreter/Interpreter.h:
+        (JSC::Interpreter::getOpcode):
+        (JSC::Interpreter::getOpcodeID):
+        * runtime/JSGlobalData.cpp:
+        (JSC::JSGlobalData::JSGlobalData):
+
 2011-12-19  Geoffrey Garen  <[email protected]>
 

trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp

@@ -541 +541 @@
     : m_sampleEntryDepth(0)
     , m_reentryDepth(0)
+#if !ASSERT_DISABLED
+    , m_initialized(false)
+#endif
+    , m_enabled(false)
+{
+}
+
+void Interpreter::initialize(bool canUseJIT)
 {
 #if ENABLE(COMPUTED_GOTO_INTERPRETER)
-    privateExecute(InitializeAndReturn, 0, 0);
-
-    for (int i = 0; i < numOpcodeIDs; ++i)
-        m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));
+    if (canUseJIT) {
+        // If the JIT is present, don't use jump destinations for opcodes.
+        
+        for (int i = 0; i < numOpcodeIDs; ++i) {
+            Opcode opcode = bitwise_cast<void*>(static_cast<uintptr_t>(i));
+            m_opcodeTable[i] = opcode;
+            m_opcodeIDTable.add(opcode, static_cast<OpcodeID>(i));
+        }
+    } else {
+        privateExecute(InitializeAndReturn, 0, 0);
+        
+        for (int i = 0; i < numOpcodeIDs; ++i)
+            m_opcodeIDTable.add(m_opcodeTable[i], static_cast<OpcodeID>(i));
+        
+        m_enabled = true;
+    }
+#else
+    UNUSED_PARAM(canUseJIT);
+#if ENABLE(INTERPRETER)
+    m_enabled = true;
+#else
+    m_enabled = false;
+#endif
 #endif // ENABLE(COMPUTED_GOTO_INTERPRETER)
+#if !ASSERT_DISABLED
+    m_initialized = true;
+#endif
 
 #if ENABLE(OPCODE_SAMPLING)
@@ -1654 +1684 @@
     }
     
+    ASSERT(m_initialized);
+    ASSERT(m_enabled);
+    
 #if ENABLE(JIT)
 #if ENABLE(INTERPRETER)

trunk/Source/JavaScriptCore/interpreter/Interpreter.h

@@ -95 +95 @@
     public:
         Interpreter();
+        
+        void initialize(bool canUseJIT);
 
         RegisterFile& registerFile() { return m_registerFile; }
@@ -100 +102 @@
         Opcode getOpcode(OpcodeID id)
         {
-            #if ENABLE(COMPUTED_GOTO_INTERPRETER)
-                return m_opcodeTable[id];
-            #else
-                return id;
-            #endif
+            ASSERT(m_initialized);
+#if ENABLE(COMPUTED_GOTO_INTERPRETER)
+            return m_opcodeTable[id];
+#else
+            return id;
+#endif
         }
 
         OpcodeID getOpcodeID(Opcode opcode)
         {
-            #if ENABLE(COMPUTED_GOTO_INTERPRETER)
-                ASSERT(isOpcode(opcode));
-                return m_opcodeIDTable.get(opcode);
-            #else
-                return opcode;
-            #endif
+            ASSERT(m_initialized);
+#if ENABLE(COMPUTED_GOTO_INTERPRETER)
+            ASSERT(isOpcode(opcode));
+            if (!m_enabled) {
+                OpcodeID result = static_cast<OpcodeID>(bitwise_cast<uintptr_t>(opcode));
+                ASSERT(result == m_opcodeIDTable.get(opcode));
+                return result;
+            }
+            return m_opcodeIDTable.get(opcode);
+#else
+            return opcode;
+#endif
         }
 
@@ -187 +196 @@
         HashMap<Opcode, OpcodeID> m_opcodeIDTable; // Maps Opcode => OpcodeID for decompiling
 #endif
+
+#if !ASSERT_DISABLED
+        bool m_initialized;
+#endif
+        bool m_enabled;
     };
 

trunk/Source/JavaScriptCore/runtime/JSGlobalData.cpp

@@ -228 +228 @@
 #endif
 
+    interpreter->initialize(this->canUseJIT());
+
     heap.notifyIsSafeToCollect();
 }