Add map method for method local variables

.mailmap

@@ -5,4 +5,5 @@ Remi Forax <forax>
 Remi Forax <forax@univ-mlv.fr>
 Eugene Kuleshov <ekuleshov>
 Andrei Loskutov <andrei>
+Jamie Mansfield <jmansfield@cadixdev.org> <dev@jamierocks.uk>
 

asm-commons/src/main/java/org/objectweb/asm/commons/ClassRemapper.java

@@ -192,7 +192,7 @@ public class ClassRemapper extends ClassVisitor {
             remappedDescriptor,
             remapper.mapSignature(signature, false),
             exceptions == null ? null : remapper.mapTypes(exceptions));
-    return methodVisitor == null ? null : createMethodRemapper(methodVisitor);
+    return methodVisitor == null ? null : createMethodRemapper(methodVisitor, name, descriptor);
   }
 
   @Override
@@ -244,10 +244,13 @@ public class ClassRemapper extends ClassVisitor {
    * {@link MethodRemapper}.
    *
    * @param methodVisitor the MethodVisitor the remapper must delegate to.
+   * @param name the name of the method
+   * @param descriptor the descriptor of the method
    * @return the newly created remapper.
    */
-  protected MethodVisitor createMethodRemapper(final MethodVisitor methodVisitor) {
-    return new MethodRemapper(api, methodVisitor, remapper);
+  protected MethodVisitor createMethodRemapper(
+      final MethodVisitor methodVisitor, final String name, final String descriptor) {
+    return new MethodRemapper(api, methodVisitor, remapper, className, name, descriptor);
   }
 
   /**

asm-commons/src/main/java/org/objectweb/asm/commons/MethodRemapper.java

@@ -45,15 +45,39 @@ public class MethodRemapper extends MethodVisitor {
   /** The remapper used to remap the types in the visited field. */
   protected final Remapper remapper;
 
+  /** The name of the class that contains the method. */
+  private final String className;
+
+  /** The name of the method itself. */
+  private final String methodName;
+
+  /** The descriptor of the method itself. */
+  private final String methodDescriptor;
+
   /**
    * Constructs a new {@link MethodRemapper}. <i>Subclasses must not use this constructor</i>.
-   * Instead, they must use the {@link #MethodRemapper(int,MethodVisitor,Remapper)} version.
+   * Instead, they must use the {@link
+   * #MethodRemapper(int,MethodVisitor,Remapper,String,String,String)} version.
    *
    * @param methodVisitor the method visitor this remapper must delegate to.
    * @param remapper the remapper to use to remap the types in the visited method.
+   * @param className the name of the class
+   * @param methodName the name of the method
+   * @param methodDescriptor the descriptor of the method
    */
-  public MethodRemapper(final MethodVisitor methodVisitor, final Remapper remapper) {
-    this(/* latest api = */ Opcodes.ASM9, methodVisitor, remapper);
+  public MethodRemapper(
+      final MethodVisitor methodVisitor,
+      final Remapper remapper,
+      final String className,
+      final String methodName,
+      final String methodDescriptor) {
+    this(
+        /* latest api = */ Opcodes.ASM9,
+        methodVisitor,
+        remapper,
+        className,
+        methodName,
+        methodDescriptor);
   }
 
   /**
@@ -65,11 +89,22 @@ public class MethodRemapper extends MethodVisitor {
    *     org.objectweb.asm.Opcodes#ASM8} or {@link org.objectweb.asm.Opcodes#ASM9}.
    * @param methodVisitor the method visitor this remapper must delegate to.
    * @param remapper the remapper to use to remap the types in the visited method.
+   * @param className the name of the class
+   * @param methodName the name of the method
+   * @param methodDescriptor the descriptor of the method
    */
   protected MethodRemapper(
-      final int api, final MethodVisitor methodVisitor, final Remapper remapper) {
+      final int api,
+      final MethodVisitor methodVisitor,
+      final Remapper remapper,
+      final String className,
+      final String methodName,
+      final String methodDescriptor) {
     super(api, methodVisitor);
     this.remapper = remapper;
+    this.className = className;
+    this.methodName = methodName;
+    this.methodDescriptor = methodDescriptor;
   }
 
   @Override
@@ -238,7 +273,8 @@ public class MethodRemapper extends MethodVisitor {
       final Label end,
       final int index) {
     super.visitLocalVariable(
-        name,
+        remapper.mapMethodLocalVariableName(
+            className, methodName, methodDescriptor, name, descriptor, index),
         remapper.mapDesc(descriptor),
         remapper.mapSignature(signature, true),
         start,

asm-commons/src/main/java/org/objectweb/asm/commons/Remapper.java

@@ -286,6 +286,27 @@ public abstract class Remapper {
     return name;
   }
 
+  /**
+   * Maps a local variable within a method to its new name. The default implementation of this
+   * method returns the given name, unchanged. Subclasses can override.
+   *
+   * @param owner the internal name of the owner class of the method.
+   * @param methodName the name of the method.
+   * @param name the name of the local variable.
+   * @param descriptor the descriptor of the local variable.
+   * @param index the index of the local variable.
+   * @return the new name of the local variable
+   */
+  public String mapMethodLocalVariableName(
+      final String owner,
+      final String methodName,
+      final String methodDescriptor,
+      final String name,
+      final String descriptor,
+      final int index) {
+    return name;
+  }
+
   /**
    * Maps an invokedynamic or a constant dynamic method name to its new name. The default
    * implementation of this method returns the given name, unchanged. Subclasses can override.

asm-commons/src/test/java/org/objectweb/asm/commons/ClassRemapperTest.java

@@ -44,6 +44,7 @@ import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.ConstantDynamic;
 import org.objectweb.asm.Handle;
+import org.objectweb.asm.Label;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
@@ -147,6 +148,40 @@ public class ClassRemapperTest extends AsmTest {
     assertEquals("b", classNode.innerClasses.get(0).innerName);
   }
 
+  @Test
+  public void testVisitMethod_visitLocalVariable() {
+    ClassNode classNode = new ClassNode();
+    ClassRemapper remapper =
+        new ClassRemapper(
+            classNode,
+            new Remapper() {
+              @Override
+              public String mapMethodLocalVariableName(
+                  final String owner,
+                  final String methodName,
+                  final String methodDescriptor,
+                  final String name,
+                  final String descriptor,
+                  final int index) {
+                if ("a".equals(name)) {
+                  return "param1";
+                }
+                if ("b".equals(name)) {
+                  return "param2";
+                }
+                return name;
+              }
+            });
+    remapper.visit(Opcodes.V1_5, Opcodes.ACC_PUBLIC, "pkg/C", null, "java/lang/Object", null);
+
+    MethodVisitor visitor = remapper.visitMethod(Opcodes.ACC_PUBLIC, "a", "(IZ)V", null, null);
+    visitor.visitLocalVariable("a", "I", null, new Label(), new Label(), 1);
+    visitor.visitLocalVariable("b", "Z", null, new Label(), new Label(), 2);
+
+    assertEquals("param1", classNode.methods.get(0).localVariables.get(0).name);
+    assertEquals("param2", classNode.methods.get(0).localVariables.get(1).name);
+  }
+
   @Test
   public void testVisitAttribute_moduleHashes() {
     ClassNode classNode = new ClassNode();