Changeset 35533 in webkit for trunk/JavaScriptCore/VM/Machine.cpp

Timestamp:

Aug 3, 2008, 2:58:21 AM (17 years ago)

Author:

[email protected]

Message:

Bug 19359: JavaScriptCore behaves differently from FF2/3 and IE when handling context in catch statement
<​https://bugs.webkit.org/show_bug.cgi?id=19359>

Reviewed by Cameron Zwarich

Make our catch behave like Firefox and IE, we do this by using a StaticScopeObject
instead of a generic JSObject for the scope node. We still don't make use of the
fact that we have a static scope inside the catch block, so the internal performance
of the catch block is not improved, even though technically it would be possible to
do so.

File:

• trunk/JavaScriptCore/VM/Machine.cpp (modified) (3 diffs)

trunk/JavaScriptCore/VM/Machine.cpp

@@ -41 +41 @@
 #include "JSNotAnObject.h"
 #include "JSPropertyNameIterator.h"
+#include "JSStaticScopeObject.h"
 #include "JSString.h"
 #include "ObjectPrototype.h"
@@ -999 +1000 @@
 }
 
+static NEVER_INLINE ScopeChainNode* createExceptionScope(ExecState* exec, CodeBlock* codeBlock, const Instruction* vPC, Register* r, ScopeChainNode* scopeChain)
+{
+    int dst = (++vPC)->u.operand;
+    Identifier& property = codeBlock->identifiers[(++vPC)->u.operand];
+    JSValue* value = r[(++vPC)->u.operand].jsValue(exec);
+    JSObject* scope = new (exec) JSStaticScopeObject(property, value, DontDelete);
+    r[dst] = scope;
+    return scopeChain->push(scope);
+}
+
 JSValue* Machine::privateExecute(ExecutionFlag flag, ExecState* exec, RegisterFile* registerFile, Register* r, ScopeChainNode* scopeChain, CodeBlock* codeBlock, JSValue** exception)
 {
@@ -2603 +2614 @@
         NEXT_OPCODE;
     }
+#if HAVE(COMPUTED_GOTO)
+    // Appease GCC
+    goto *(&&skip_new_scope);
+#endif
+    BEGIN_OPCODE(op_push_new_scope) {
+        /* new_scope dst(r) property(id) value(r)
+         
+           Constructs a new StaticScopeObject with property set to value.  That scope
+           object is then pushed onto the ScopeChain.  The scope object is then stored
+           in dst for GC.
+         */
+        setScopeChain(exec, scopeChain, createExceptionScope(exec, codeBlock, vPC, r, scopeChain));
+        vPC += 4;
+        NEXT_OPCODE;
+    }
+#if HAVE(COMPUTED_GOTO)
+    skip_new_scope:
+#endif
     BEGIN_OPCODE(op_catch) {
         /* catch ex(r)