wasm gc: optimize null checks, casts and try/catch using branching instructions

core/src/main/java/org/teavm/backend/wasm/disasm/DisassemblyCodeListener.java

@@ -143,7 +143,7 @@ public class DisassemblyCodeListener extends BaseDisassemblyListener implements
         writer.write(" ");
         writeType(sourceType);
         writer.write(" ");
-        writeType(sourceType);
+        writeType(targetType);
         writer.eol();
     }
 

core/src/main/java/org/teavm/backend/wasm/generate/WasmGenerationVisitor.java

@@ -179,16 +179,6 @@ public class WasmGenerationVisitor extends BaseWasmGenerationVisitor {
         return true;
     }
 
-    @Override
-    protected void catchException(TextLocation location, List<WasmExpression> target, WasmLocal local,
-            String exceptionClass, WasmLocal exceptionVar) {
-        if (local != null) {
-            var save = new WasmSetLocal(local, new WasmGetLocal(exceptionVar));
-            save.setLocation(location);
-            target.add(save);
-        }
-    }
-
     @Override
     protected WasmType mapType(ValueType type) {
         return WasmGeneratorUtil.mapType(type);

core/src/main/java/org/teavm/backend/wasm/generate/common/methods/BaseWasmGenerationVisitor.java

@@ -1300,12 +1300,16 @@ public abstract class BaseWasmGenerationVisitor implements StatementVisitor, Exp
         for (int i = tryCatchStatements.size() - 1; i >= 0; --i) {
             var tryCatch = tryCatchStatements.get(i);
             var catchBlock = catchBlocks.get(i);
+            var blockType = mapType(tryCatch.getExceptionType() != null
+                    ? ValueType.object(tryCatch.getExceptionType())
+                    : ValueType.object("java.lang.Throwable"));
+            currentBlock.setType(blockType);
             if (tryCatch.getExceptionType() != null && !tryCatch.getExceptionType().equals(Throwable.class.getName())) {
-                var exceptionType = ValueType.object(tryCatch.getExceptionType());
+                checkExceptionType(tryCatch, exceptionVar, innerCatchBlock.getBody(), currentBlock);
-                var isMatched = generateInstanceOf(new WasmGetLocal(exceptionVar), exceptionType);
-                innerCatchBlock.getBody().add(new WasmBranch(isMatched, currentBlock));
             } else {
-                innerCatchBlock.getBody().add(new WasmBreak(currentBlock));
+                var br = new WasmBreak(currentBlock);
+                br.setResult(new WasmGetLocal(exceptionVar));
+                innerCatchBlock.getBody().add(br);
                 catchesAll = true;
             }
             currentBlock = catchBlock;
@@ -1320,12 +1324,16 @@ public abstract class BaseWasmGenerationVisitor implements StatementVisitor, Exp
         for (int i = tryCatchStatements.size() - 1; i >= 0; --i) {
             var tryCatch = tryCatchStatements.get(i);
             var catchBlock = catchBlocks.get(i);
-            catchBlock.getBody().add(currentBlock);
 
             var catchLocal = tryCatch.getExceptionVariable() != null
                     ? localVar(tryCatch.getExceptionVariable())
                     : null;
-            catchException(null, catchBlock.getBody(), catchLocal, tryCatch.getExceptionType(), exceptionVar);
+            if (catchLocal != null) {
+                var save = new WasmSetLocal(localVar(tryCatch.getExceptionVariable()), currentBlock);
+                catchBlock.getBody().add(save);
+            } else {
+                catchBlock.getBody().add(new WasmDrop(currentBlock));
+            }
             visitMany(tryCatch.getHandler(), catchBlock.getBody());
             if (!catchBlock.isTerminating() && catchBlock != outerCatchBlock) {
                 catchBlock.getBody().add(new WasmBreak(outerCatchBlock));
@@ -1337,8 +1345,12 @@ public abstract class BaseWasmGenerationVisitor implements StatementVisitor, Exp
         tempVars.release(exceptionVar);
     }
 
-    protected abstract void catchException(TextLocation location, List<WasmExpression> target, WasmLocal local,
+    protected void checkExceptionType(TryCatchStatement tryCatch, WasmLocal exceptionVar, List<WasmExpression> target,
-            String exceptionClass, WasmLocal exceptionVar);
+            WasmBlock targetBlock) {
+        var exceptionType = ValueType.object(tryCatch.getExceptionType());
+        var isMatched = generateInstanceOf(new WasmGetLocal(exceptionVar), exceptionType);
+        target.add(new WasmBranch(isMatched, targetBlock));
+    }
 
     private void visitMany(List<Statement> statements, List<WasmExpression> target) {
         var oldTarget = resultConsumer;

core/src/main/java/org/teavm/backend/wasm/generate/gc/methods/WasmGCGenerationVisitor.java

@@ -19,12 +19,15 @@ import java.util.List;
 import java.util.function.Supplier;
 import org.teavm.ast.ArrayType;
 import org.teavm.ast.BinaryExpr;
+import org.teavm.ast.CastExpr;
 import org.teavm.ast.ConditionalExpr;
 import org.teavm.ast.Expr;
+import org.teavm.ast.InstanceOfExpr;
 import org.teavm.ast.InvocationExpr;
 import org.teavm.ast.InvocationType;
 import org.teavm.ast.QualificationExpr;
 import org.teavm.ast.SubscriptExpr;
+import org.teavm.ast.TryCatchStatement;
 import org.teavm.backend.wasm.BaseWasmFunctionRepository;
 import org.teavm.backend.wasm.WasmFunctionTypes;
 import org.teavm.backend.wasm.gc.PreciseTypeInference;
@@ -50,6 +53,8 @@ import org.teavm.backend.wasm.model.expression.WasmBlock;
 import org.teavm.backend.wasm.model.expression.WasmCall;
 import org.teavm.backend.wasm.model.expression.WasmCallReference;
 import org.teavm.backend.wasm.model.expression.WasmCast;
+import org.teavm.backend.wasm.model.expression.WasmCastBranch;
+import org.teavm.backend.wasm.model.expression.WasmCastCondition;
 import org.teavm.backend.wasm.model.expression.WasmDrop;
 import org.teavm.backend.wasm.model.expression.WasmExpression;
 import org.teavm.backend.wasm.model.expression.WasmGetGlobal;
@@ -68,9 +73,11 @@ import org.teavm.backend.wasm.model.expression.WasmSignedType;
 import org.teavm.backend.wasm.model.expression.WasmStructGet;
 import org.teavm.backend.wasm.model.expression.WasmStructNewDefault;
 import org.teavm.backend.wasm.model.expression.WasmStructSet;
+import org.teavm.backend.wasm.model.expression.WasmTest;
 import org.teavm.backend.wasm.model.expression.WasmThrow;
 import org.teavm.backend.wasm.model.expression.WasmUnreachable;
 import org.teavm.model.ClassHierarchy;
+import org.teavm.model.ElementModifier;
 import org.teavm.model.FieldReference;
 import org.teavm.model.MethodReference;
 import org.teavm.model.TextLocation;
@@ -245,18 +252,14 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
         }
         result.acceptVisitor(typeInference);
         block.setType(typeInference.getResult());
-        var cachedValue = exprCache.create(result, typeInference.getResult(), location, block.getBody());
+        var check = new WasmNullBranch(WasmNullCondition.NOT_NULL, result, block);
-
+        block.getBody().add(check);
-        var check = new WasmNullBranch(WasmNullCondition.NOT_NULL, cachedValue.expr(), block);
-        check.setResult(cachedValue.expr());
-        block.getBody().add(new WasmDrop(check));
 
         var callSiteId = generateCallSiteId(location);
         callSiteId.generateRegister(block.getBody(), location);
         generateThrowNPE(location, block.getBody());
         callSiteId.generateThrow(block.getBody(), location);
 
-        cachedValue.release();
         return block;
     }
 
@@ -382,6 +385,59 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
         return supertypeCall;
     }
 
+    @Override
+    public void visit(InstanceOfExpr expr) {
+        var type = expr.getType();
+        if (canCastNatively(type)) {
+            var wasmType = context.classInfoProvider().getClassInfo(type).getStructure().getNonNullReference();
+            acceptWithType(expr.getExpr(), type);
+            var wasmValue = result;
+            result.acceptVisitor(typeInference);
+
+            result = new WasmTest(wasmValue, wasmType);
+            result.setLocation(expr.getLocation());
+        } else {
+            super.visit(expr);
+        }
+    }
+
+    @Override
+    public void visit(CastExpr expr) {
+        var type = expr.getTarget();
+        if (!expr.isWeak() && canCastNatively(type)) {
+            var wasmType = context.classInfoProvider().getClassInfo(type).getType();
+            var block = new WasmBlock(false);
+            acceptWithType(expr.getValue(), type);
+            var wasmValue = result;
+            result.acceptVisitor(typeInference);
+            var sourceWasmType = (WasmType.Reference) typeInference.getResult();
+            if (sourceWasmType == null || !validateCastTypes(sourceWasmType, wasmType, expr.getLocation())) {
+                return;
+            }
+
+            block.setType(wasmType);
+            block.setLocation(expr.getLocation());
+            block.getBody().add(new WasmCastBranch(WasmCastCondition.SUCCESS, wasmValue, sourceWasmType,
+                    wasmType, block));
+            generateThrowCCE(expr.getLocation(), block.getBody());
+            result = block;
+        } else {
+            super.visit(expr);
+        }
+    }
+
+    private boolean canCastNatively(ValueType type) {
+        if (type instanceof ValueType.Array) {
+            return true;
+        }
+        var className = ((ValueType.Object) type).getClassName();
+        var cls = context.classes().get(className);
+        if (cls == null) {
+            return false;
+        }
+        return !cls.hasModifier(ElementModifier.INTERFACE);
+    }
+
     @Override
     protected WasmExpression generateCast(WasmExpression value, WasmType targetType) {
         return new WasmCast(value, (WasmType.Reference) targetType);
@@ -435,18 +491,13 @@ public class WasmGCGenerationVisitor extends BaseWasmGenerationVisitor {
     }
 
     @Override
-    protected void catchException(TextLocation location, List<WasmExpression> target, WasmLocal local,
+    protected void checkExceptionType(TryCatchStatement tryCatch, WasmLocal exceptionVar, List<WasmExpression> target,
-            String exceptionClass, WasmLocal exceptionVar) {
+            WasmBlock targetBlock) {
-        if (local != null) {
+        var wasmType = context.classInfoProvider().getClassInfo(tryCatch.getExceptionType()).getType();
-            WasmExpression exception = new WasmGetLocal(exceptionVar);
+        var wasmSourceType = context.classInfoProvider().getClassInfo("java.lang.Throwable").getType();
-            if (exceptionClass != null && !exceptionClass.equals("java.lang.Throwable")) {
+        var br = new WasmCastBranch(WasmCastCondition.SUCCESS, new WasmGetLocal(exceptionVar),
-                exception = new WasmCast(exception, context.classInfoProvider().getClassInfo(exceptionClass)
+                wasmSourceType, wasmType, targetBlock);
-                        .getStructure().getNonNullReference());
+        target.add(br);
-            }
-            var save = new WasmSetLocal(local, exception);
-            save.setLocation(location);
-            target.add(save);
-        }
     }
 
     @Override

core/src/main/java/org/teavm/backend/wasm/model/expression/WasmCastBranch.java

@@ -30,6 +30,7 @@ public class WasmCastBranch extends WasmExpression {
             WasmType.Reference type, WasmBlock target) {
         this.condition = Objects.requireNonNull(condition);
         this.value = Objects.requireNonNull(value);
+        this.sourceType = Objects.requireNonNull(sourceType);
         this.type = Objects.requireNonNull(type);
         this.target = Objects.requireNonNull(target);
     }

core/src/main/java/org/teavm/backend/wasm/parser/CodeParser.java

@@ -816,9 +816,9 @@ public class CodeParser extends BaseSectionParser {
     }
 
     private void parseCastBranch(boolean success) {
+        var flags = reader.data[reader.ptr++];
         var depth = readLEB();
         var target = blockStack.get(blockStack.size() - depth - 1);
-        var flags = reader.data[reader.ptr++];
         var sourceType = reader.readHeapType((flags & 1) != 0);
         var targetType = reader.readHeapType((flags & 2) != 0);
         codeListener.castBranch(success, depth, target.token, sourceType, targetType);

core/src/main/java/org/teavm/backend/wasm/render/WasmBinaryRenderingVisitor.java

@@ -236,7 +236,6 @@ class WasmBinaryRenderingVisitor implements WasmExpressionVisitor {
                 writer.writeByte(25);
                 break;
         }
-        writeLabel(expression.getTarget());
         var flags = 0;
         if (expression.getSourceType().isNullable()) {
             flags |= 1;
@@ -245,6 +244,7 @@ class WasmBinaryRenderingVisitor implements WasmExpressionVisitor {
             flags |= 2;
         }
         writer.writeByte(flags);
+        writeLabel(expression.getTarget());
         writer.writeHeapType(expression.getSourceType(), module);
         writer.writeHeapType(expression.getType(), module);
         popLocation();