Author: kohsuke
Date: Wed Dec 28 17:03:25 2005
New Revision: 359670
URL: http://svn.apache.org/viewcvs?rev=359670&view=rev
Log:
fixed another instrumentation issue in a rather ad-hoc way.
A proper fix would require more sophisticated stack analysis.
for now just do a simple pattern-match to find what javac often produces.
-----
// if there are any dup_x2 following new and dup,
replace them with dup.
// some java compiler generates such bytecode for code
like
// someObject.someStringField += "abc"
//
// which yield
// NEW StringBuffer
// DUP
// ALOAD // someObject
// DUP_x2
// GETFIELD someStringField
// INVOKESPECIAL StringBuffer.<init>
// LDC "abc"
// INVOKEVIRTUAL StringBuffer.append
// INVOKEVIRTUAL StringBuffer.toString
// PUTFIELD someStringField
//
// replacing this DUP_x2 -> DUP is required for moving
the new.
Modified:
jakarta/commons/sandbox/javaflow/trunk/src/java/org/apache/commons/javaflow/bytecode/transformation/bcel/BcelClassTransformer.java
Modified:
jakarta/commons/sandbox/javaflow/trunk/src/java/org/apache/commons/javaflow/bytecode/transformation/bcel/BcelClassTransformer.java
URL:
http://svn.apache.org/viewcvs/jakarta/commons/sandbox/javaflow/trunk/src/java/org/apache/commons/javaflow/bytecode/transformation/bcel/BcelClassTransformer.java?rev=359670&r1=359669&r2=359670&view=diff
==============================================================================
---
jakarta/commons/sandbox/javaflow/trunk/src/java/org/apache/commons/javaflow/bytecode/transformation/bcel/BcelClassTransformer.java
(original)
+++
jakarta/commons/sandbox/javaflow/trunk/src/java/org/apache/commons/javaflow/bytecode/transformation/bcel/BcelClassTransformer.java
Wed Dec 28 17:03:25 2005
@@ -438,6 +438,30 @@
insList.delete(next);
next = newnext;
}
+ // if there are any dup_x2 following new and dup,
replace them with dup.
+ // some java compiler generates such bytecode for code
like
+ // someObject.someStringField += "abc"
+ //
+ // which yield
+ // NEW StringBuffer
+ // DUP
+ // ALOAD // someObject
+ // DUP_x2
+ // GETFIELD someStringField
+ // INVOKESPECIAL StringBuffer.<init>
+ // LDC "abc"
+ // INVOKEVIRTUAL StringBuffer.append
+ // INVOKEVIRTUAL StringBuffer.toString
+ // PUTFIELD someStringField
+ //
+ // replacing this DUP_x2 -> DUP is required for moving
the new.
+ if(next!=null && next.getNext()!=null &&
next.getNext().getInstruction().getOpcode() == Constants.DUP_X2) {
+ InstructionHandle dupx2ptr = next.getNext();
+ final InstructionHandle newnext =
dupx2ptr.getNext();
+ insList.insert(dupx2ptr, InstructionConstants.DUP);
+ insList.delete(dupx2ptr);
+ next = newnext;
+ }
final InstructionTargeter[] targeter =
ins.getTargeters();
if (targeter != null) {
final InstructionHandle newnext = ins.getNext();
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