Wasm: working on parser

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

@@ -0,0 +1,105 @@
+/*
+ *  Copyright 2022 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.backend.wasm.disasm;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.util.function.Consumer;
+import org.teavm.backend.wasm.model.WasmType;
+import org.teavm.backend.wasm.parser.CodeSectionListener;
+import org.teavm.backend.wasm.parser.CodeSectionParser;
+import org.teavm.backend.wasm.parser.ModuleParser;
+import org.teavm.common.ByteArrayAsyncInputStream;
+
+public class DisasmCodeSectionListener implements CodeSectionListener {
+    private PrintWriter writer;
+
+    public DisasmCodeSectionListener(PrintWriter writer) {
+        this.writer = writer;
+    }
+
+    @Override
+    public void address(int address) {
+        writer.print("(; ");
+        for (int i = 7; i >= 0; --i) {
+            var digit = (address >>> (i * 4)) & 0xF;
+            writer.print(Character.forDigit(digit, 16));
+        }
+        writer.print(" ;)");
+        writer.println();
+    }
+
+    @Override
+    public void sectionStart(int functionCount) {
+        writer.println("  .code functions=" + functionCount);
+    }
+
+    @Override
+    public boolean functionStart(int index, int size) {
+        writer.println("  function fn_" + index);
+        return true;
+    }
+
+    @Override
+    public void localsStart(int count) {
+        writer.println("  locals " + count);
+    }
+
+    @Override
+    public void local(int start, int count, WasmType type) {
+        for (int i = 0; i < count; ++i) {
+            writer.println("  local " + (i + start) + ": " + type);
+        }
+    }
+
+    @Override
+    public void localsEnd() {
+        writer.println("  end_locals");
+    }
+
+    @Override
+    public void functionEnd() {
+        writer.println("  end_function");
+    }
+
+    @Override
+    public void sectionEnd() {
+        writer.println("  end_code");
+    }
+
+    public static void main(String[] args) throws IOException {
+        var file = new File(args[0]);
+        var bytes = Files.readAllBytes(file.toPath());
+        var input = new ByteArrayAsyncInputStream(bytes);
+        var parser = new ModuleParser(input) {
+            @Override
+            protected Consumer<byte[]> getSectionConsumer(int code, int pos, String name) {
+                if (code == 10) {
+                    return bytes -> {
+                        var writer = new PrintWriter(System.out);
+                        var sectionParser = new CodeSectionParser(new DisasmCodeSectionListener(writer));
+                        sectionParser.parse(bytes);
+                        writer.flush();
+                    };
+                }
+                return null;
+            }
+        };
+        input.readFully(parser::parse);
+    }
+}

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

@@ -0,0 +1,36 @@
+/*
+ *  Copyright 2022 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.backend.wasm.parser;
+
+import org.teavm.backend.wasm.model.WasmType;
+
+public interface CodeSectionListener {
+    void address(int address);
+
+    void sectionStart(int functionCount);
+
+    boolean functionStart(int index, int size);
+
+    void localsStart(int count);
+
+    void local(int start, int count, WasmType type);
+
+    void localsEnd();
+
+    void functionEnd();
+
+    void sectionEnd();
+}

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

@@ -0,0 +1,115 @@
+/*
+ *  Copyright 2022 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.backend.wasm.parser;
+
+import org.teavm.backend.wasm.model.WasmType;
+
+public class CodeSectionParser {
+    private CodeSectionListener listener;
+    private byte[] data;
+    private int ptr;
+    private int lastReportedPtr = -1;
+
+    public CodeSectionParser(CodeSectionListener listener) {
+        this.listener = listener;
+    }
+
+    public void parse(byte[] data) {
+        this.data = data;
+        ptr = 0;
+        try {
+            parseFunctions();
+        } finally {
+            this.data = null;
+        }
+    }
+
+    private void parseFunctions() {
+        reportAddress();
+        int count = readLEB();
+        listener.sectionStart(count);
+        for (var i = 0; i < count; ++i) {
+            parseFunction(i);
+        }
+        reportAddress();
+        listener.sectionEnd();
+    }
+
+    private void parseFunction(int index) {
+        reportAddress();
+        var functionSize = readLEB();
+        var end = ptr + functionSize;
+        if (listener.functionStart(index, functionSize)) {
+            parseLocals();
+        }
+        ptr = end;
+        reportAddress();
+        listener.functionEnd();
+    }
+
+    private void parseLocals() {
+        reportAddress();
+        var localEntries = readLEB();
+        listener.localsStart(localEntries);
+        var localIndex = 0;
+        for (int i = 0; i < localEntries; ++i) {
+            reportAddress();
+            var countInGroup = readLEB();
+            var type = readType();
+            listener.local(localIndex, countInGroup, type);
+            localIndex += countInGroup;
+        }
+        reportAddress();
+        listener.localsEnd();
+    }
+
+    private WasmType readType() {
+        var typeId = data[ptr];
+        switch (typeId) {
+            case 0x7F:
+                return WasmType.INT32;
+            case 0x7E:
+                return WasmType.INT64;
+            case 0x7D:
+                return WasmType.FLOAT32;
+            case 0x7C:
+                return WasmType.FLOAT64;
+            default:
+                return null;
+        }
+    }
+
+    private void reportAddress() {
+        if (ptr != lastReportedPtr) {
+            lastReportedPtr = ptr;
+            listener.address(ptr);
+        }
+    }
+
+    private int readLEB() {
+        var result = 0;
+        var shift = 0;
+        while (true) {
+            var digit = data[ptr++];
+            result |= (digit & 0x7F) << shift;
+            if ((digit & 0x80) == 0) {
+                break;
+            }
+            shift += 7;
+        }
+        return result;
+    }
+}