Changeset 126718 in webkit for trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Aug 26, 2012, 5:49:25 PM (13 years ago)

Author:

[email protected]

Message:

Finally inlining should correctly track the catch context
​https://bugs.webkit.org/show_bug.cgi?id=94986
<rdar://problem/11753784>

Reviewed by Sam Weinig.

Source/JavaScriptCore:

This fixes two behaviors:

1) Throwing from a finally block. Previously, we would seem to reenter the finally

block - though only once.

2) Executing a finally block from some nested context, for example due to a

'continue', 'break', or 'return' in the try. This would execute the finally
block in the context of of the try block, which could lead to either scope depth
mismatches or reexecutions of the finally block on throw, similarly to (1) but
for different reasons.

• bytecompiler/BytecodeGenerator.cpp:

(JSC):
(JSC::BytecodeGenerator::pushFinallyContext):
(JSC::BytecodeGenerator::emitComplexJumpScopes):
(JSC::BytecodeGenerator::pushTry):
(JSC::BytecodeGenerator::popTryAndEmitCatch):

• bytecompiler/BytecodeGenerator.h:

(FinallyContext):
(TryData):
(JSC):
(TryContext):
(TryRange):
(BytecodeGenerator):

• bytecompiler/NodesCodegen.cpp:

(JSC::TryNode::emitBytecode):

LayoutTests:

• fast/js/jsc-test-list:
• fast/js/script-tests/throw-from-finally.js: Added.
• fast/js/throw-from-finally.html: Added.
• fast/js/throw-from-finally-expected.txt: Added.

File:

• trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -1971 +1971 @@
     generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine(), column());
 
+    ASSERT(m_catchBlock || m_finallyBlock);
+
     RefPtr<Label> tryStartLabel = generator.newLabel();
+    generator.emitLabel(tryStartLabel.get());
+    
     if (m_finallyBlock)
         generator.pushFinallyContext(m_finallyBlock);
-
-    generator.emitLabel(tryStartLabel.get());
+    TryData* tryData = generator.pushTry(tryStartLabel.get());
+
     generator.emitNode(dst, m_tryBlock);
 
@@ -1986 +1990 @@
         // Uncaught exception path: the catch block.
         RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());
-        RefPtr<RegisterID> exceptionRegister = generator.emitCatch(generator.newTemporary(), tryStartLabel.get(), here.get());
+        RefPtr<RegisterID> exceptionRegister = generator.popTryAndEmitCatch(tryData, generator.newTemporary(), here.get());
+        
+        if (m_finallyBlock) {
+            // If the catch block throws an exception and we have a finally block, then the finally
+            // block should "catch" that exception.
+            tryData = generator.pushTry(here.get());
+        }
+        
         generator.emitPushNewScope(exceptionRegister.get(), m_exceptionIdent, exceptionRegister.get());
         generator.emitNode(dst, m_catchBlock);
@@ -1994 +2005 @@
 
     if (m_finallyBlock) {
+        RefPtr<Label> preFinallyLabel = generator.emitLabel(generator.newLabel().get());
+        
         generator.popFinallyContext();
 
@@ -2003 +2016 @@
 
         // Uncaught exception path: invoke the finally block, then re-throw the exception.
-        RefPtr<Label> here = generator.emitLabel(generator.newLabel().get());
-        RefPtr<RegisterID> tempExceptionRegister = generator.emitCatch(generator.newTemporary(), tryStartLabel.get(), here.get());
+        RefPtr<RegisterID> tempExceptionRegister = generator.popTryAndEmitCatch(tryData, generator.newTemporary(), preFinallyLabel.get());
         generator.emitNode(dst, m_finallyBlock);
         generator.emitThrow(tempExceptionRegister.get());