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correct LOOP detection in an ELSE block

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This commit is contained in:
Volker Berlin 2022-02-20 18:32:07 +01:00
parent d4cf26ee05
commit d629fbcd02
1 changed files with 17 additions and 3 deletions
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20
src/de/inetsoftware/jwebassembly/module/BranchManager.java
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@ -126,7 +126,7 @@ class BranchManager {
* the current line number
*/
void addReturnOperator( int startPosition, int nextPosition, int lineNumber ) {
allParsedOperations.add( new ParsedBlock( JavaBlockOperator.RETURN, startPosition, 0, nextPosition, lineNumber ) );
allParsedOperations.add( new ParsedBlock( JavaBlockOperator.RETURN, startPosition, Integer.MAX_VALUE - startPosition, nextPosition, lineNumber ) );
}
/**
@ -188,6 +188,7 @@ class BranchManager {
* the parsed operations
*/
private void addLoops( List<ParsedBlock> parsedOperations ) {
MAIN:
for( int b = 0; b < parsedOperations.size(); b++ ) {
ParsedBlock parsedBlock = parsedOperations.get( b );
if( parsedBlock.startPosition > parsedBlock.endPosition ) {
@ -229,6 +230,15 @@ class BranchManager {
// if<cond> START:
// we can not match this in WASM because a missing GOTO that we need to move the condition to the start of the loop
int nextPos = parsedBlock.nextPosition;
for( int n = b - 1; n >= 0; n-- ) {
ParsedBlock block = parsedOperations.get( n );
if( block.op == JavaBlockOperator.IF && block.endPosition == nextPos ) {
// a normal GOTO before the ELSE
continue MAIN;
}
}
for( int n = b + 1; n < parsedOperations.size(); n++ ) {
ParsedBlock nextBlock = parsedOperations.get( n );
if( nextBlock.op == JavaBlockOperator.IF && nextBlock.endPosition == nextPos ) { // Eclipse loop with normal goto
@ -242,7 +252,7 @@ class BranchManager {
// The GOTO from the ELSE and the jump to the end of the WHILE loop is merged to one GOTO.
for( n = b - 1; n >= 0; n-- ) {
ParsedBlock prevBlock = parsedOperations.get( n );
if( prevBlock.endPosition > nextPos ) {
if( prevBlock.endPosition > nextPos && prevBlock.endPosition < conditionStart ) {
conditionStart = prevBlock.endPosition;
prevBlock.endPosition = parsedBlock.nextPosition;
// Create the second GOTO
@ -252,6 +262,9 @@ class BranchManager {
break;
}
}
if( conditionStart == conditionEnd ) {
throw new WasmException( "Loop condition start not found. Jump from " + parsedBlock.startPosition + " to " + parsedBlock.endPosition, parsedBlock.lineNumber );
}
}
convertToLoop( parsedBlock, conditionStart, conditionEnd );
@ -1064,6 +1077,7 @@ class BranchManager {
parent = parent.parent;
deep++;
}
throw new WasmException( "GOTO code without target loop/block. Jump from " + start + " to " + jump, gotoBlock.lineNumber );
} else {
if( gotoBlock.nextPosition == jump ) {
//A GOTO to the next position is like a NOP and can be ignored.
@ -1838,7 +1852,7 @@ class BranchManager {
* @param endPosition
* the Jump position
*/
public BreakBlock( BranchNode branch, int breakPos, int endPosition ) {
public BreakBlock( @Nonnull BranchNode branch, int breakPos, int endPosition ) {
this.breakPos = breakPos;
this.endPosition = endPosition;
this.branch = branch;