improve the compiling of exceptions

src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java

@@ -847,7 +847,7 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
                 break;
             case BLOCK:
                 codeStream.writeOpCode( BLOCK );
-                codeStream.writeValueType( ValueType.empty ); // void; the return type of the block. currently we does not use it
+                codeStream.writeValueType( data == null ? ValueType.empty : (ValueType)data ); // void; the return type of the block. 
                 break;
             case BR:
                 codeStream.writeOpCode( BR );
@@ -879,6 +879,18 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
             case CATCH:
                 codeStream.writeOpCode( CATCH );
                 break;
+            case THROW:
+                codeStream.writeOpCode( THROW );
+                codeStream.writeVaruint32( 0 );             // event/exception ever 0 because currently there is only one with signature anyref
+                break;
+            case RETHROW:
+                codeStream.writeOpCode( RETHROW );
+                break;
+            case BR_ON_EXN:
+                codeStream.writeOpCode( BR_ON_EXN );
+                codeStream.writeVaruint32( (Integer)data ); // break depth
+                codeStream.writeVaruint32( 0 );             // event/exception ever 0 because currently there is only one with signature anyref
+                break;
             default:
                 throw new Error( "Unknown block: " + op );
         }

src/de/inetsoftware/jwebassembly/module/BranchManger.java

@@ -48,7 +48,9 @@ class BranchManger {
 
     private final HashMap<Integer, ParsedBlock> loops               = new HashMap<>();
 
-    private final List<WasmInstruction> instructions;
+    private final List<WasmInstruction>         instructions;
+
+    private TryCatchFinally[]                   exceptionTable;
 
     /**
      * Create a branch manager.
@@ -71,7 +73,7 @@ class BranchManger {
         root.clear();
         loops.clear();
         root.endPos = code.getCodeSize();
-        TryCatchFinally[] exceptionTable = code.getExceptionTable();
+        exceptionTable = code.getExceptionTable();
         for( TryCatchFinally ex : exceptionTable ) {
             allParsedOperations.add( new TryCatchParsedBlock( ex ) );
         }
@@ -588,6 +590,36 @@ class BranchManger {
 
     /**
      * Calculate the needed nodes for try/catch
+     * Sample: The follow Java code:
+     * 
+     * <pre>
+     * try {
+     *   code1
+     * catch(Exception ex)
+     *   code2
+     * }
+     * code3
+     * </pre>
+     *
+     * Should be converted to the follow Wasm code for tableswitch:
+     * 
+     * <pre>
+     * block
+     *   block (result anyref)
+     *     try
+     *       code1
+     *     catch
+     *       br_on_exn 1 0
+     *       rethrow
+     *     end
+     *     br 1
+     *   end
+     *   local.set x
+     *   code2
+     * end
+     * code3
+     * </pre>
+     *
      * @param parent
      *            the parent branch
      * @param tryBlock
@@ -595,14 +627,14 @@ class BranchManger {
      * @param parsedOperations
      *            the not consumed operations in the parent branch
      */
-    private void calculateTry ( BranchNode parent, TryCatchParsedBlock tryBlock, List<ParsedBlock> parsedOperations ) {
+    private void calculateTry( BranchNode parent, TryCatchParsedBlock tryBlock, List<ParsedBlock> parsedOperations ) {
         TryCatchFinally tryCatch = tryBlock.tryCatch;
 
         int gotoPos = tryCatch.getEnd(); // alternativ we can use tryCatch.getHandler()-3
         int endPos = parent.endPos;
         for( int i = 0; i < parsedOperations.size(); i++ ) {
             ParsedBlock parsedBlock = parsedOperations.get( i );
-            if( parsedBlock.startPosition == gotoPos && parsedBlock.op == JavaBlockOperator.GOTO && parsedBlock.startPosition < parsedBlock.endPosition) {
+            if( parsedBlock.startPosition == gotoPos && parsedBlock.op == JavaBlockOperator.GOTO && parsedBlock.startPosition < parsedBlock.endPosition ) {
                 parsedOperations.remove( i );
                 endPos = parsedBlock.endPosition;
                 break;
@@ -611,8 +643,40 @@ class BranchManger {
                 break;
             }
         }
-        parent.add( new BranchNode( tryBlock.startPosition, tryCatch.getHandler(), WasmBlockOperator.TRY, null ) );
+        int startPos = tryBlock.startPosition;
-        parent.add( new BranchNode( tryCatch.getHandler(), endPos, WasmBlockOperator.CATCH, WasmBlockOperator.END ) );
+        int catchPos = tryCatch.getHandler();
+        BranchNode node = new BranchNode( startPos, endPos, WasmBlockOperator.BLOCK, WasmBlockOperator.END );
+        parent.add( node );
+        parent = node;
+
+        node = new BranchNode( startPos, catchPos, WasmBlockOperator.BLOCK, WasmBlockOperator.END, ValueType.anyref );
+        parent.add( node );
+        parent = node;
+
+        parent.add( new BranchNode( startPos, catchPos, WasmBlockOperator.TRY, null ) );
+        BranchNode catchNode = new BranchNode( catchPos, catchPos, WasmBlockOperator.CATCH, WasmBlockOperator.END );
+        parent.add( catchNode );
+
+        catchNode.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.BR_ON_EXN, null, 1 ) );
+        catchNode.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.RETHROW, null ) );
+
+        parent.add( new BranchNode( catchPos, catchPos, WasmBlockOperator.BR, null, 1 ) );
+    }
+
+    /**
+     * Check if there are a start of a catch block on the code position.
+     * 
+     * @param codePosition
+     *            the code position
+     * @return true, if there is a catch block
+     */
+    boolean isCatch( int codePosition ) {
+        for( TryCatchFinally tryCatch : exceptionTable ) {
+            if( tryCatch.getHandler() == codePosition ) {
+                return true;
+            }
+        }
+        return false;
     }
 
     /**

src/de/inetsoftware/jwebassembly/module/JavaMethodWasmCodeBuilder.java

@@ -241,7 +241,11 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
                     case 76: // astore_1
                     case 77: // astore_2
                     case 78: // astore_3
-                        storeType = findPreviousPushInstructionPushValueType();
+                        if( branchManager.isCatch( codePos ) ) {
+                            storeType = ValueType.anyref; // for the catch there are no previous instructions
+                        } else {
+                            storeType = findPreviousPushInstructionPushValueType();
+                        }
                         addLoadStoreInstruction( storeType, false, op - 75, codePos );
                         break;
                     case 79: // iastore
@@ -556,7 +560,7 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
                         ref = (ConstantRef)constantPool.get( byteCode.readUnsignedShort() );
                         addStructInstruction( StructOperator.SET, ref.getClassName(), ref.getName(), codePos );
                         break;
-                    //TODO case 182: // invokevirtual
+                    case 182: // invokevirtual
                     case 183: // invokespecial, invoke a constructor
                     case 184: // invokestatic
                         idx = byteCode.readUnsignedShort();
@@ -603,7 +607,9 @@ class JavaMethodWasmCodeBuilder extends WasmCodeBuilder {
                     case 190: // arraylength
                         addArrayInstruction( ArrayOperator.LENGTH, ValueType.i32, codePos );
                         break;
-                    //TODO case 191: // athrow
+                    case 191: // athrow
+                        addBlockInstruction( WasmBlockOperator.THROW, null, codePos );
+                        break;
                     //TODO case 192: // checkcast
                     //TODO case 193: // instanceof
                     //TODO case 194: // monitorenter

src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java

@@ -389,6 +389,9 @@ public class TextModuleWriter extends ModuleWriter {
                 break;
             case BLOCK:
                 name = "block";
+                if( data != null ) {
+                    name += " (result " + data + ")";
+                }
                 insetAfter++;
                 break;
             case BR:
@@ -420,6 +423,15 @@ public class TextModuleWriter extends ModuleWriter {
                 name = "catch";
                 insetAfter++;
                 break;
+            case THROW:
+                name = "throw 0"; // currently there is only one event/exception with anyref
+                break;
+            case RETHROW:
+                name = "rethrow";
+                break;
+            case BR_ON_EXN:
+                name = "br_on_exn " + data + " 0"; // br_on_exn, break depth, event; // currently there is only one event/exception with anyref
+                break;
             default:
                 throw new Error( "Unknown block: " + op );
         }

src/de/inetsoftware/jwebassembly/wasm/WasmBlockOperator.java

@@ -1,5 +1,5 @@
 /*
-   Copyright 2018 Volker Berlin (i-net software)
+   Copyright 2018 - 2019 Volker Berlin (i-net software)
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
@@ -36,4 +36,7 @@ public enum WasmBlockOperator {
     UNREACHABLE,
     TRY,
     CATCH,
+    THROW,
+    RETHROW,
+    BR_ON_EXN,
 }