Fixed bug #316360.

src/org/objectweb/asm/ClassReader.java

@@ -1142,7 +1142,7 @@ public class ClassReader {
         u += 2;
 
         // generates the first (implicit) stack map frame
-        if (FRAMES && (stackMap != 0 || unzip)) {
+        if (FRAMES && stackMap != 0) {
             /*
              * for the first explicit frame the offset is not offset_delta + 1
              * but only offset_delta; setting the implicit frame offset to -1
@@ -1159,8 +1159,6 @@ public class ClassReader {
             if (unzip) {
                 getImplicitFrame(context);
             }
-        }
-        if (FRAMES && stackMap != 0) {
             /*
              * Finds labels for UNINITIALIZED frame types. Instead of decoding
              * each element of the stack map table, we look for 3 consecutive
@@ -1198,17 +1196,19 @@ public class ClassReader {
                 }
             }
 
-            // visits the frame(s) for this offset, if any
+            // visits the frame for this offset, if any
             while (FRAMES && frame != null
                     && (frame.offset == offset || frame.offset == -1)) {
                 // if there is a frame for this offset, makes the visitor visit
                 // it, and reads the next frame if there is one.
-                if (!zip || unzip) {
-                    mv.visitFrame(Opcodes.F_NEW, frame.localCount, frame.local,
-                            frame.stackCount, frame.stack);
-                } else if (frame.offset != -1) {
-                    mv.visitFrame(frame.mode, frame.localDiff, frame.local,
-                            frame.stackCount, frame.stack);
+                if (frame.offset != -1) {
+                    if (!zip || unzip) {
+                        mv.visitFrame(Opcodes.F_NEW, frame.localCount,
+                                frame.local, frame.stackCount, frame.stack);
+                    } else {
+                        mv.visitFrame(frame.mode, frame.localDiff, frame.local,
+                                frame.stackCount, frame.stack);
+                    }
                 }
                 if (frameCount > 0) {
                     stackMap = readFrame(stackMap, zip, unzip, labels, frame);

src/org/objectweb/asm/MethodVisitor.java

@@ -184,13 +184,9 @@ public abstract class MethodVisitor {
      * compressed form (all frames must use the same format, i.e. you must not
      * mix expanded and compressed frames within a single method):
      * <ul>
-     * <li>In expanded form, all frames must have the F_NEW type, and a first
-     * frame corresponding to the method signature must be explicitly visited
-     * before the first instruction.</li>
+     * <li>In expanded form, all frames must have the F_NEW type.</li>
      * <li>In compressed form, frames are basically "deltas" from the state of
-     * the previous frame (the first frame, corresponding to the method's
-     * parameters and access flags, is implicit in this form, and must not be
-     * visited):
+     * the previous frame:
      * <ul>
      * <li>{@link Opcodes#F_SAME} representing frame with exactly the same
      * locals as the previous frame and with the empty stack.</li>
@@ -207,7 +203,11 @@ public abstract class MethodVisitor {
      * are absent and with the empty stack (<code>nLocals</code> is 1, 2 or 3).</li>
      * <li>{@link Opcodes#F_FULL} representing complete frame data.</li></li>
      * </ul>
-     * </ul>
+     * </ul> <br>
+     * In both cases the first frame, corresponding to the method's parameters
+     * and access flags, is implicit and must not be visited. Also, it is
+     * illegal to visit two or more frames for the same code location (i.e., at
+     * least one instruction must be visited between two calls to visitFrame).
      * 
      * @param type
      *            the type of this stack map frame. Must be

src/org/objectweb/asm/MethodWriter.java

@@ -42,8 +42,8 @@ class MethodWriter extends MethodVisitor {
     /**
      * Pseudo access flag used to denote constructors.
      */
-    static final int ACC_CONSTRUCTOR = 262144;
-
+    static final int ACC_CONSTRUCTOR = 0x80000;
+    
     /**
      * Frame has exactly the same locals as the previous stack map frame and
      * number of stack items is zero.
@@ -256,11 +256,6 @@ class MethodWriter extends MethodVisitor {
      */
     private int[] previousFrame;
 
-    /**
-     * Index of the next element to be added in {@link #frame}.
-     */
-    private int frameIndex;
-
     /**
      * The current stack map frame. The first element contains the offset of the
      * instruction to which the frame corresponds, the second element is the
@@ -430,6 +425,9 @@ class MethodWriter extends MethodVisitor {
         cw.lastMethod = this;
         this.cw = cw;
         this.access = access;
+        if ("<init>".equals(name)) {
+            this.access |= ACC_CONSTRUCTOR;
+        }
         this.name = cw.newUTF8(name);
         this.desc = cw.newUTF8(desc);
         this.descriptor = desc;
@@ -445,9 +443,6 @@ class MethodWriter extends MethodVisitor {
         }
         this.compute = computeFrames ? FRAMES : (computeMaxs ? MAXS : NOTHING);
         if (computeMaxs || computeFrames) {
-            if (computeFrames && "<init>".equals(name)) {
-                this.access |= ACC_CONSTRUCTOR;
-            }
             // updates maxLocals
             int size = Type.getArgumentsAndReturnSizes(descriptor) >> 2;
             if ((access & Opcodes.ACC_STATIC) != 0) {
@@ -550,8 +545,11 @@ class MethodWriter extends MethodVisitor {
         }
 
         if (type == Opcodes.F_NEW) {
+            if (previousFrame == null) {
+                visitImplicitFirstFrame();
+            }
             currentLocals = nLocal;
-            startFrame(code.length, nLocal, nStack);
+            int frameIndex = startFrame(code.length, nLocal, nStack);
             for (int i = 0; i < nLocal; ++i) {
                 if (local[i] instanceof String) {
                     frame[frameIndex++] = Frame.OBJECT
@@ -1334,8 +1332,8 @@ class MethodWriter extends MethodVisitor {
                         }
                         code.data[end] = (byte) Opcodes.ATHROW;
                         // emits a frame for this unreachable block
-                        startFrame(start, 0, 1);
-                        frame[frameIndex++] = Frame.OBJECT
+                        int frameIndex = startFrame(start, 0, 1);
+                        frame[frameIndex] = Frame.OBJECT
                                 | cw.addType("java/lang/Throwable");
                         endFrame();
                         // removes the start-end range from the exception
@@ -1562,7 +1560,7 @@ class MethodWriter extends MethodVisitor {
             }
         }
         // visits the frame and its content
-        startFrame(f.owner.position, nLocal, nStack);
+        int frameIndex = startFrame(f.owner.position, nLocal, nStack);
         for (i = 0; nLocal > 0; ++i, --nLocal) {
             t = locals[i];
             frame[frameIndex++] = t;
@@ -1580,6 +1578,67 @@ class MethodWriter extends MethodVisitor {
         endFrame();
     }
 
+    /**
+     * Visit the implicit first frame of this method.
+     */
+    private void visitImplicitFirstFrame() {
+        // There can be at most descriptor.length() + 1 locals
+        int frameIndex = startFrame(0, descriptor.length() + 1, 0);
+        if ((access & Opcodes.ACC_STATIC) == 0) {
+            if ((access & ACC_CONSTRUCTOR) == 0) {
+                frame[frameIndex++] = Frame.OBJECT | cw.addType(cw.thisName);
+            } else {
+                frame[frameIndex++] = 6; // Opcodes.UNINITIALIZED_THIS;
+            }
+        }
+        int i = 1;
+        loop: while (true) {
+            int j = i;
+            switch (descriptor.charAt(i++)) {
+            case 'Z':
+            case 'C':
+            case 'B':
+            case 'S':
+            case 'I':
+                frame[frameIndex++] = 1; // Opcodes.INTEGER;
+                break;
+            case 'F':
+                frame[frameIndex++] = 2; // Opcodes.FLOAT;
+                break;
+            case 'J':
+                frame[frameIndex++] = 4; // Opcodes.LONG;
+                break;
+            case 'D':
+                frame[frameIndex++] = 3; // Opcodes.DOUBLE;
+                break;
+            case '[':
+                while (descriptor.charAt(i) == '[') {
+                    ++i;
+                }
+                if (descriptor.charAt(i) == 'L') {
+                    ++i;
+                    while (descriptor.charAt(i) != ';') {
+                        ++i;
+                    }
+                }
+                frame[frameIndex++] = Frame.OBJECT
+                        | cw.addType(descriptor.substring(j, ++i));
+                break;
+            case 'L':
+                while (descriptor.charAt(i) != ';') {
+                    ++i;
+                }
+                frame[frameIndex++] = Frame.OBJECT
+                        | cw.addType(descriptor.substring(j + 1, i++));
+                break;
+            default:
+                break loop;
+            }
+        }
+        frame[1] = frameIndex - 3;
+        endFrame();
+    }
+
     /**
      * Starts the visit of a stack map frame.
      * 
@@ -1589,8 +1648,9 @@ class MethodWriter extends MethodVisitor {
      *            the number of local variables in the frame.
      * @param nStack
      *            the number of stack elements in the frame.
+     * @return the index of the next element to be written in this frame.
      */
-    private void startFrame(final int offset, final int nLocal, final int nStack) {
+    private int startFrame(final int offset, final int nLocal, final int nStack) {
         int n = 3 + nLocal + nStack;
         if (frame == null || frame.length < n) {
             frame = new int[n];
@@ -1598,7 +1658,7 @@ class MethodWriter extends MethodVisitor {
         frame[0] = offset;
         frame[1] = nLocal;
         frame[2] = nStack;
-        frameIndex = 3;
+        return 3;
     }
 
     /**
@@ -1896,7 +1956,8 @@ class MethodWriter extends MethodVisitor {
      */
     final void put(final ByteVector out) {
         final int FACTOR = ClassWriter.TO_ACC_SYNTHETIC;
-        int mask = Opcodes.ACC_DEPRECATED | ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
+        int mask = ACC_CONSTRUCTOR | Opcodes.ACC_DEPRECATED
+                | ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
                 | ((access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) / FACTOR);
         out.putShort(access & ~mask).putShort(name).putShort(desc);
         if (classReaderOffset != 0) {

src/org/objectweb/asm/optimizer/shrink.properties

@@ -194,7 +194,7 @@ org/objectweb/asm/MethodWriter.frameCount=u
 org/objectweb/asm/MethodWriter.stackMap=v
 org/objectweb/asm/MethodWriter.previousFrameOffset=w
 org/objectweb/asm/MethodWriter.previousFrame=x
-org/objectweb/asm/MethodWriter.frameIndex=y
+#org/objectweb/asm/MethodWriter.frameIndex=y
 org/objectweb/asm/MethodWriter.frame=z
 org/objectweb/asm/MethodWriter.handlerCount=A
 org/objectweb/asm/MethodWriter.firstHandler=B
@@ -333,7 +333,8 @@ org/objectweb/asm/MethodWriter.readShort([BI)S=b
 org/objectweb/asm/MethodWriter.readUnsignedShort([BI)I=c
 org/objectweb/asm/MethodWriter.writeShort([BII)V=a
 org/objectweb/asm/MethodWriter.visitFrame(Lorg/objectweb/asm/Frame;)V=b
-org/objectweb/asm/MethodWriter.startFrame(III)V=a
+org/objectweb/asm/MethodWriter.visitImplicitFirstFrame()V=f
+org/objectweb/asm/MethodWriter.startFrame(III)I=a
 org/objectweb/asm/MethodWriter.endFrame()V=b
 org/objectweb/asm/MethodWriter.writeFrame()V=c
 org/objectweb/asm/MethodWriter.resizeInstructions()V=d

src/org/objectweb/asm/util/CheckMethodAdapter.java

@@ -111,11 +111,6 @@ public class CheckMethodAdapter extends MethodVisitor {
      */
     private Set<Label> usedLabels;
 
-    /**
-     * If an explicit first frame has been visited before the first instruction.
-     */
-    private boolean hasExplicitFirstFrame;
-
     /**
      * Number of visited frames in expanded form.
      */
@@ -126,6 +121,11 @@ public class CheckMethodAdapter extends MethodVisitor {
      */
     private int compressedFrames;
 
+    /**
+     * Number of instructions before the last visited frame.
+     */
+    private int lastFrame = -1;
+
     /**
      * The exception handler ranges. Each pair of list element contains the
      * start and end labels of an exception handler block.
@@ -506,6 +506,11 @@ public class CheckMethodAdapter extends MethodVisitor {
     @Override
     public void visitFrame(final int type, final int nLocal,
             final Object[] local, final int nStack, final Object[] stack) {
+        if (insnCount == lastFrame) {
+            throw new IllegalStateException(
+                    "At most one frame can be visited at a given code location.");
+        }
+        lastFrame = insnCount;
         int mLocal;
         int mStack;
         switch (type) {
@@ -561,13 +566,6 @@ public class CheckMethodAdapter extends MethodVisitor {
             checkFrameValue(stack[i]);
         }
         if (type == Opcodes.F_NEW) {
-            if (insnCount == 0) {
-                hasExplicitFirstFrame = true;
-            } else if (!hasExplicitFirstFrame) {
-                throw new RuntimeException(
-                        "In expanded form, a first frame must be explicitly "
-                                + "visited before the first instruction.");
-            }
             ++expandedFrames;
         } else {
             ++compressedFrames;