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first steps to compile loops

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This commit is contained in:
Volker Berlin 2018-05-20 11:54:06 +02:00
parent 652d6c3d6a
commit c8ef4fd3c7
2 changed files with 110 additions and 3 deletions
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112
src/de/inetsoftware/jwebassembly/module/BranchManger.java
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@ -19,6 +19,8 @@ package de.inetsoftware.jwebassembly.module;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import de.inetsoftware.classparser.CodeInputStream;
@ -32,9 +34,11 @@ import de.inetsoftware.jwebassembly.WasmException;
*/
class BranchManger {
private final ArrayList<ParsedBlock> allParsedOperations = new ArrayList<>();
private final ArrayList<ParsedBlock> allParsedOperations = new ArrayList<>();
private final BranchNode root = new BranchNode( 0, Integer.MAX_VALUE, null, null );
private final BranchNode root = new BranchNode( 0, Integer.MAX_VALUE, null, null );
private final HashMap<Integer, ParsedBlock> loops = new HashMap<>();
/**
* Remove all branch information for reusing the manager.
@ -42,6 +46,7 @@ class BranchManger {
void reset() {
allParsedOperations.clear();
root.clear();
loops.clear();
}
/**
@ -84,9 +89,40 @@ class BranchManger {
* Calculate all block operators from the parsed information.
*/
void calculate() {
addLoops();
Collections.sort( allParsedOperations, (a,b) -> Integer.compare( a.startPosition, b.startPosition ) );
calculate( root, allParsedOperations );
}
/**
* In the compiled Java byte code there is no marker for the start of loop. But we need this marker. That we add a
* virtual loop operator on the target position of GOTO operators with a negative offset.
*/
private void addLoops() {
for( ParsedBlock parsedBlock : allParsedOperations ) {
if( parsedBlock.op == JavaBlockOperator.GOTO && parsedBlock.startPosition > parsedBlock.endPosition ) {
int start = parsedBlock.endPosition;
ParsedBlock loop = loops.get( start );
if( loop == null ) {
loop = new ParsedBlock( JavaBlockOperator.LOOP, start, 0, parsedBlock.lineNumber );
loops.put( start, loop );
}
loop.endPosition = parsedBlock.startPosition + 3;
}
}
for( ParsedBlock loop : loops.values() ) {
for( int i = 0; i < allParsedOperations.size(); i++ ) {
ParsedBlock parsedBlock = allParsedOperations.get( i );
if( loop.startPosition < parsedBlock.startPosition && loop.endPosition < parsedBlock.endPosition ) {
// fix overlapping from structures
loop.endPosition = parsedBlock.endPosition;
}
}
}
allParsedOperations.addAll( loops.values() );
}
/**
* Calculate the branch tree for the given branch and parsed sub operations.
*
@ -103,6 +139,12 @@ class BranchManger {
case SWITCH:
caculateSwitch( parent, (SwitchParsedBlock)parsedBlock, parsedOperations );
break;
case GOTO:
caculateGoto( parent, parsedBlock, parsedOperations );
break;
case LOOP:
caculateLoop( parent, parsedBlock, parsedOperations );
break;
default:
throw new WasmException( "Unimplemented block code operation: " + parsedBlock.op, null, parsedBlock.lineNumber );
}
@ -126,7 +168,7 @@ class BranchManger {
BranchNode branch = null;
for( ; i < parsedOperations.size(); i++ ) {
ParsedBlock parsedBlock = parsedOperations.get( i );
if( parsedBlock.startPosition == gotoPos && parsedBlock.op == JavaBlockOperator.GOTO ) {
if( parsedBlock.startPosition == gotoPos && parsedBlock.op == JavaBlockOperator.GOTO && parsedBlock.startPosition < parsedBlock.endPosition) {
parsedOperations.remove( i );
branch = new BranchNode( startBlock.startPosition, startBlock.endPosition, WasmBlockOperator.IF, null );
parent.add( branch );
@ -323,6 +365,59 @@ class BranchManger {
int block;
}
/**
* The not consumed GOTO operators of IF THEN ELSE must be break or continue in a loop.
*
* @param parent
* the parent branch
* @param gotoBlock
* the GOTO operation
* @param parsedOperations
* the not consumed operations in the parent branch
*/
private void caculateGoto ( BranchNode parent, ParsedBlock gotoBlock, List<ParsedBlock> parsedOperations ) {
int start = gotoBlock.endPosition;
int end = gotoBlock.startPosition;
if( end > start ) {
int deep = 0;
while( parent != null ) {
if( parent.startOp == WasmBlockOperator.LOOP && parent.startPos == start ) {
parent.add( new BranchNode( end, end, WasmBlockOperator.BR, null, deep ) ); // continue to the start of the loop
return;
}
parent = parent.parent;
deep++;
}
}
throw new WasmException( "GOTO code without target loop/block", null, gotoBlock.lineNumber );
}
/**
* Calculate the needed nodes for a loop.
* @param parent
* the parent branch
* @param loopBlock
* the virtual LOOP operation
* @param parsedOperations
* the not consumed operations in the parent branch
*/
private void caculateLoop ( BranchNode parent, ParsedBlock loopBlock, List<ParsedBlock> parsedOperations ) {
BranchNode loopNode = new BranchNode( loopBlock.startPosition, loopBlock.endPosition, WasmBlockOperator.LOOP, WasmBlockOperator.END );
parent.add( loopNode );
int idx = 0;
for( ; idx < parsedOperations.size(); idx++ ) {
ParsedBlock parsedBlock = parsedOperations.get( idx );
if( parsedBlock.startPosition >= loopBlock.endPosition ) {
break;
}
}
calculate( loopNode, parsedOperations.subList( 0, idx ) );
// add the "br 0" as last child to receive the right order
loopNode.add( new BranchNode( loopBlock.endPosition, loopBlock.endPosition, WasmBlockOperator.BR, null, 0 ) ); // continue to the start of the loop
}
/**
* Check on every instruction position if there any branch is ending
*
@ -390,6 +485,8 @@ class BranchManger {
private Object data;
private BranchNode parent;
/**
* Create a new description.
*
@ -428,6 +525,15 @@ class BranchManger {
this.data = data;
}
/**
* {@inheritDoc}
*/
@Override
public boolean add( BranchNode e ) {
e.parent = this;
return super.add( e );
}
void handle( int codePositions, ModuleWriter writer ) throws IOException {
if( codePositions < startPos || codePositions > endPos ) {
return;

1
src/de/inetsoftware/jwebassembly/module/JavaBlockOperator.java
View File

@ -26,4 +26,5 @@ public enum JavaBlockOperator {
IF,
GOTO,
SWITCH,
LOOP,
}