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fix drop exnref in a try/finally structure

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This commit is contained in:
Volker Berlin 2020-04-19 17:35:56 +02:00
parent df8aade0fa
commit d99eb77de8
1 changed files with 50 additions and 11 deletions
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61
src/de/inetsoftware/jwebassembly/module/BranchManger.java
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@ -89,6 +89,10 @@ class BranchManger {
root.endPos = code.getCodeSize();
exceptionTable = code.getExceptionTable();
for( TryCatchFinally ex : exceptionTable ) {
if ( ex.getStart() == ex.getHandler() ) {
// see with end of synchronized block, compiled with Eclipse 2019-09
continue;
}
allParsedOperations.add( new TryCatchParsedBlock( ex ) );
}
}
@ -937,10 +941,10 @@ class BranchManger {
TryCatchFinally tryCat = catches.get( i );
int blockGotoPos = tryCat.getHandler()-3;
for( int p = 0; p < parsedOperations.size(); p++ ) {
ParsedBlock parsedBlock = parsedOperations.get( p );
for( idx = 0; idx < parsedOperations.size(); idx++ ) {
ParsedBlock parsedBlock = parsedOperations.get( idx );
if( parsedBlock.startPosition == blockGotoPos && parsedBlock.op == JavaBlockOperator.GOTO && parsedBlock.startPosition < parsedBlock.endPosition ) {
parsedOperations.remove( p );
parsedOperations.remove( idx );
break;
}
if( parsedBlock.startPosition > blockGotoPos ) {
@ -956,17 +960,35 @@ class BranchManger {
instructions.remove( instrPos ); // every catch block store the exception from the stack but in WASM we can do this only once for all exceptions
}
// calculate branch operations inside the CATCH/FINALLY blocks
do {
for( idx = 0; idx < parsedOperations.size(); idx++ ) {
ParsedBlock parsedBlock = parsedOperations.get( idx );
if( parsedBlock.startPosition > node.endPos ) {
break;
}
}
if( idx > 0 ) {
calculate( node, parsedOperations.subList( 0, idx ) );
}
if( node == catchNode ) {
break;
}
node = node.parent;
} while( node != catchNode );
// Create the unboxing and the type check of the exceptions from the catch blocks
if( tryCatch.isFinally() ) {
catchNode.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.DROP, null ) );
int instrPos = findIdxOfCodePos( catchPos ) + 1;
WasmInstruction instr = instructions.get( instrPos );
if( instr.getType() == Type.Block && ((WasmBlockInstruction)instr).getOperation() == WasmBlockOperator.DROP ) {
// occur with a RETURN in a finally block
// We does not need to unbox if the value will be drop
} else {
addUnboxExnref( catchNode );
}
} else {
// unboxing the exnref on the stack to a reference of the exception
BranchNode unBoxing = new BranchNode( catchPos, catchPos, WasmBlockOperator.BLOCK, WasmBlockOperator.END, options.getCatchType() );
catchNode.add( 0, unBoxing );
//TODO localVariables.getTempVariable( ValueType.exnref, catchPos, endPos ); https://github.com/WebAssembly/wabt/issues/1388
unBoxing.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.BR_ON_EXN, null, 0 ) );
unBoxing.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.RETHROW, null ) );
addUnboxExnref( catchNode );
// add a "if $exception instanceof type" check to the WASM code
StructType type = options.types.valueOf( tryCatch.getType().getName() );
@ -987,6 +1009,23 @@ class BranchManger {
}
}
/**
* Add an unboxing of the WASm exnref on the stack
*
* @param catchNode
* the catch node
*/
private void addUnboxExnref( BranchNode catchNode ) {
// unboxing the exnref on the stack to a reference of the exception
int catchPos = catchNode.startPos;
BranchNode unBoxing = new BranchNode( catchPos, catchPos, WasmBlockOperator.BLOCK, WasmBlockOperator.END, options.getCatchType() );
catchNode.add( 0, unBoxing );
//TODO localVariables.getTempVariable( ValueType.exnref, catchPos, endPos ); https://github.com/WebAssembly/wabt/issues/1388
unBoxing.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.BR_ON_EXN, null, 0 ) );
unBoxing.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.RETHROW, null ) );
}
/**
* Check if there are a start of a catch block on the code position.
*