add option WASM_USE_EH to ignore exception support because currently not supported

src/de/inetsoftware/jwebassembly/JWebAssembly.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2018 Volker Berlin (i-net software)
+ * Copyright 2017 - 2020 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.
@@ -93,6 +93,11 @@ public class JWebAssembly {
      */
     public static final String WASM_USE_GC = "wasm.use_gc";
 
+    /**
+     * If the exception handling feature of WASM should be use or an unreachable instruction. If true use the exception instructions of WASM.
+     */
+    public static final String WASM_USE_EH = "wasm.use_eh";
+
     /**
      * The logger instance
      */

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

@@ -1248,8 +1248,12 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
                 codeStream.writeOpCode( CATCH );
                 break;
             case THROW:
-                codeStream.writeOpCode( THROW );
+                if( options.useEH() ) {
-                codeStream.writeVaruint32( 0 );             // event/exception ever 0 because currently there is only one with signature anyref
+                    codeStream.writeOpCode( THROW );
+                    codeStream.writeVaruint32( 0 );             // event/exception ever 0 because currently there is only one with signature anyref
+                } else {
+                    codeStream.writeOpCode( UNREACHABLE );
+                }
                 break;
             case RETHROW:
                 codeStream.writeOpCode( RETHROW );

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

@@ -514,7 +514,9 @@ public class ModuleGenerator {
                             case CATCH:
                             case THROW:
                             case RETHROW:
-                                writer.writeException();
+                                if( writer.options.useEH() ) {
+                                    writer.writeException();
+                                }
                                 break;
                             default:
                         }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2019 Volker Berlin (i-net software)
+ * Copyright 2017 - 2020 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.
@@ -762,7 +762,7 @@ public class TextModuleWriter extends ModuleWriter {
                 insetAfter++;
                 break;
             case THROW:
-                name = "throw 0"; // currently there is only one event/exception with anyref
+                name = options.useEH() ? "throw 0" : "unreachable"; // currently there is only one event/exception with anyref
                 break;
             case RETHROW:
                 name = "rethrow";

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 - 2019 Volker Berlin (i-net software)
+ * Copyright 2017 - 2020 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.
@@ -33,6 +33,8 @@ public class WasmOptions {
 
     private final boolean useGC;
 
+    private final boolean useEH;
+
     @Nonnull
     private final String  sourceMapBase;
 
@@ -50,6 +52,7 @@ public class WasmOptions {
     public WasmOptions( HashMap<String, String> properties ) {
         debugNames = Boolean.parseBoolean( properties.get( JWebAssembly.DEBUG_NAMES ) );
         useGC = Boolean.parseBoolean( properties.getOrDefault( JWebAssembly.WASM_USE_GC, "false" ) );
+        useEH = Boolean.parseBoolean( properties.getOrDefault( JWebAssembly.WASM_USE_EH, "false" ) );
         String base = properties.getOrDefault( JWebAssembly.SOURCE_MAP_BASE, "" );
         if( !base.isEmpty() && !base.endsWith( "/" ) ) {
             base += "/";
@@ -75,6 +78,15 @@ public class WasmOptions {
         return useGC;
     }
 
+    /**
+     * If the exception handling feature of WASM should be use or an unreachable instruction.
+     * 
+     * @return true, use the EH instructions of WASM; false, generate an unreachable instruction
+     */
+    public boolean useEH() {
+        return useEH;
+    }
+
     /**
      * Get the relative path between the final wasm file location and the source files location.
      * If not empty it should end with a slash like "../../src/main/java/". 

test/de/inetsoftware/jwebassembly/runtime/Exceptions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018 - 2019 Volker Berlin (i-net software)
+ * Copyright 2018 - 2020 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.
@@ -23,6 +23,7 @@ import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runners.Parameterized.Parameters;
 
+import de.inetsoftware.jwebassembly.JWebAssembly;
 import de.inetsoftware.jwebassembly.ScriptEngine;
 import de.inetsoftware.jwebassembly.WasmRule;
 import de.inetsoftware.jwebassembly.api.annotation.Export;
@@ -47,6 +48,7 @@ public class Exceptions extends AbstractBaseTest {
             addParam( list, script, "complex" );
         }
         rule.setTestParameters( list );
+        rule.setProperty( JWebAssembly.WASM_USE_EH, "true" );
         return list;
     }