Changeset 103292 in webkit for trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp

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):

File:

• trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp (modified) (2 diffs)

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)