Merge branch '317748-non-regression' into 'master'

Add a non-regression test for issue #317748.

See merge request asm/asm!97

asm/src/main/java/org/objectweb/asm/Attribute.java

@@ -277,4 +277,47 @@ public class Attribute {
       attribute = attribute.nextAttribute;
     }
   }
+
+  /** A set of attribute prototypes (attributes with the same type are considered equal). */
+  static final class Set {
+
+    private static final int SIZE_INCREMENT = 6;
+
+    private int size;
+    private Attribute[] data = new Attribute[SIZE_INCREMENT];
+
+    void addAttributes(final Attribute attributeList) {
+      Attribute attribute = attributeList;
+      while (attribute != null) {
+        if (!contains(attribute)) {
+          add(attribute);
+        }
+        attribute = attribute.nextAttribute;
+      }
+    }
+
+    Attribute[] toArray() {
+      Attribute[] result = new Attribute[size];
+      System.arraycopy(data, 0, result, 0, size);
+      return result;
+    }
+
+    private boolean contains(final Attribute attribute) {
+      for (int i = 0; i < size; ++i) {
+        if (data[i].type.equals(attribute.type)) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    private void add(final Attribute attribute) {
+      if (size >= data.length) {
+        Attribute[] newData = new Attribute[data.length + SIZE_INCREMENT];
+        System.arraycopy(data, 0, newData, 0, size);
+        data = newData;
+      }
+      data[size++] = attribute;
+    }
+  }
 }

asm/src/main/java/org/objectweb/asm/ClassWriter.java

@@ -601,6 +601,7 @@ public class ClassWriter extends ClassVisitor {
     // Third step: do a ClassReader->ClassWriter round trip if the generated class contains ASM
     // specific instructions due to large forward jumps.
     if (hasAsmInstructions) {
+      Attribute[] attributes = getAttributePrototypes();
       firstField = null;
       lastField = null;
       firstMethod = null;
@@ -613,13 +614,37 @@ public class ClassWriter extends ClassVisitor {
       firstAttribute = null;
       compute = hasFrames ? MethodWriter.COMPUTE_INSERTED_FRAMES : MethodWriter.COMPUTE_NOTHING;
       new ClassReader(result.data, 0, /* checkClassVersion = */ false)
-          .accept(this, (hasFrames ? ClassReader.EXPAND_FRAMES : 0) | ClassReader.EXPAND_ASM_INSNS);
+          .accept(
+              this,
+              attributes,
+              (hasFrames ? ClassReader.EXPAND_FRAMES : 0) | ClassReader.EXPAND_ASM_INSNS);
       return toByteArray();
     } else {
       return result.data;
     }
   }
 
+  /**
+   * Returns the prototypes of the attributes used by this class, its fields and its methods.
+   *
+   * @return the prototypes of the attributes used by this class, its fields and its methods.
+   */
+  private Attribute[] getAttributePrototypes() {
+    Attribute.Set attributePrototypes = new Attribute.Set();
+    attributePrototypes.addAttributes(firstAttribute);
+    FieldWriter fieldWriter = firstField;
+    while (fieldWriter != null) {
+      fieldWriter.collectAttributePrototypes(attributePrototypes);
+      fieldWriter = (FieldWriter) fieldWriter.fv;
+    }
+    MethodWriter methodWriter = firstMethod;
+    while (methodWriter != null) {
+      methodWriter.collectAttributePrototypes(attributePrototypes);
+      methodWriter = (MethodWriter) methodWriter.mv;
+    }
+    return attributePrototypes.toArray();
+  }
+
   // -----------------------------------------------------------------------------------------------
   // Utility methods: constant pool management for Attribute sub classes
   // -----------------------------------------------------------------------------------------------

asm/src/main/java/org/objectweb/asm/FieldWriter.java

@@ -334,4 +334,13 @@ final class FieldWriter extends FieldVisitor {
       firstAttribute.putAttributes(symbolTable, output);
     }
   }
+
+  /**
+   * Collects the attributes of this field into the given set of attribute prototypes.
+   *
+   * @param attributePrototypes a set of attribute prototypes.
+   */
+  final void collectAttributePrototypes(final Attribute.Set attributePrototypes) {
+    attributePrototypes.addAttributes(firstAttribute);
+  }
 }

asm/src/main/java/org/objectweb/asm/MethodWriter.java

@@ -2303,4 +2303,14 @@ final class MethodWriter extends MethodVisitor {
       firstAttribute.putAttributes(symbolTable, output);
     }
   }
+
+  /**
+   * Collects the attributes of this method into the given set of attribute prototypes.
+   *
+   * @param attributePrototypes a set of attribute prototypes.
+   */
+  final void collectAttributePrototypes(final Attribute.Set attributePrototypes) {
+    attributePrototypes.addAttributes(firstAttribute);
+    attributePrototypes.addAttributes(firstCodeAttribute);
+  }
 }

asm/src/test/java/org/objectweb/asm/ClassWriterTest.java

@@ -325,13 +325,21 @@ public class ClassWriterTest extends AsmTest {
 
     ClassReader classReader = new ClassReader(classFile);
     ClassWriter classWriter = new ClassWriter(0);
-    ClassVisitor classVisitor = new NopInserter(apiParameter.value(), classWriter);
+    ForwardJumpNopInserter forwardJumpNopInserter =
+        new ForwardJumpNopInserter(apiParameter.value(), classWriter);
 
     if (classParameter.isMoreRecentThan(apiParameter)) {
-      assertThrows(RuntimeException.class, () -> classReader.accept(classVisitor, attributes(), 0));
+      assertThrows(
+          RuntimeException.class,
+          () -> classReader.accept(forwardJumpNopInserter, attributes(), 0));
       return;
     }
-    classReader.accept(classVisitor, attributes(), 0);
+    classReader.accept(forwardJumpNopInserter, attributes(), 0);
+    if (!forwardJumpNopInserter.transformed) {
+      classWriter = new ClassWriter(0);
+      classReader.accept(
+          new WideForwardJumpInserter(apiParameter.value(), classWriter), attributes(), 0);
+    }
 
     byte[] transformedClass = classWriter.toByteArray();
     assertThat(() -> loadAndInstantiate(classParameter.getName(), transformedClass))
@@ -559,11 +567,12 @@ public class ClassWriterTest extends AsmTest {
     }
   }
 
-  private static class NopInserter extends ClassVisitor {
+  /** Inserts NOP instructions after the first forward jump found, to get a wide jump. */
+  private static class ForwardJumpNopInserter extends ClassVisitor {
 
-    boolean transformed = false;
+    boolean transformed;
 
-    NopInserter(final int api, final ClassVisitor classVisitor) {
+    ForwardJumpNopInserter(final int api, final ClassVisitor classVisitor) {
       super(api, classVisitor);
     }
 
@@ -597,4 +606,61 @@ public class ClassWriterTest extends AsmTest {
       };
     }
   }
+
+  /** Inserts a wide forward jump in the first non-abstract method that is found. */
+  private static class WideForwardJumpInserter extends ClassVisitor {
+
+    private boolean needFrames;
+    private boolean transformed;
+
+    WideForwardJumpInserter(final int api, final ClassVisitor classVisitor) {
+      super(api, classVisitor);
+    }
+
+    @Override
+    public void visit(
+        final int version,
+        final int access,
+        final String name,
+        final String signature,
+        final String superName,
+        final String[] interfaces) {
+      needFrames = (version & 0xFFFF) >= Opcodes.V1_7;
+      super.visit(version, access, name, signature, superName, interfaces);
+    }
+
+    @Override
+    public MethodVisitor visitMethod(
+        final int access,
+        final String name,
+        final String descriptor,
+        final String signature,
+        final String[] exceptions) {
+      return new MethodVisitor(
+          api, super.visitMethod(access, name, descriptor, signature, exceptions)) {
+
+        @Override
+        public void visitCode() {
+          super.visitCode();
+          if (!transformed) {
+            Label startLabel = new Label();
+            visitJumpInsn(Opcodes.GOTO, startLabel);
+            if (needFrames) {
+              visitLabel(new Label());
+              visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+            }
+            for (int i = 0; i <= Short.MAX_VALUE; ++i) {
+              visitInsn(Opcodes.NOP);
+            }
+            visitLabel(startLabel);
+            if (needFrames) {
+              visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+              visitInsn(Opcodes.NOP);
+            }
+            transformed = true;
+          }
+        }
+      };
+    }
+  }
 }