Update of /cvsroot/fb-contrib/fb-contrib/src/com/mebigfatguy/fbcontrib/detect
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv1245/src/com/mebigfatguy/fbcontrib/detect
Modified Files:
BloatedSynchronizedBlock.java
Log Message:
keep track of local variables that are aliases to the results of methods calls on this. Consider all such loads on these variables as unsafe.
Index: BloatedSynchronizedBlock.java
===================================================================
RCS file: /cvsroot/fb-contrib/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/BloatedSynchronizedBlock.java,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -d -r1.4 -r1.5
--- BloatedSynchronizedBlock.java 2 Jan 2006 14:57:11 -0000 1.4
+++ BloatedSynchronizedBlock.java 2 Jan 2006 16:44:01 -0000 1.5
@@ -18,7 +18,11 @@
*/
package com.mebigfatguy.fbcontrib.detect;
+import java.util.HashSet;
+import java.util.Set;
+
import org.apache.bcel.classfile.Method;
+import org.apache.bcel.generic.Type;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
@@ -31,11 +35,12 @@
private BugReporter bugReporter;
private static final String BSB_MIN_SAFE_CODE_SIZE = "fb-contrib.bsb.minsize";
private OpcodeStack stack = new OpcodeStack();
+ private Set<Integer> unsafeAliases = new HashSet<Integer>();
private int syncPC;
private int lastPC;
- private int monitorReg;
private boolean isStatic;
private int minSafeCodeLength;
+ private boolean thisCallOccurred;
/**
* constructs a BSB detector given the reporter to report bugs on
@@ -68,8 +73,9 @@
else
syncPC = -1;
lastPC = -1;
- monitorReg = -1;
isStatic = obj.isStatic();
+ unsafeAliases.clear();
+ thisCallOccurred = false;
stack.resetForMethodEntry(this);
}
@@ -81,12 +87,39 @@
*/
public void sawOpcode(int seen) {
try {
+ if (thisCallOccurred && ((seen == ASTORE) || ((seen >= ASTORE_0) && (seen <= ASTORE_3)))) {
+ int storeReg = astoreReg(seen);
+ if (storeReg >= 0)
+ unsafeAliases.add(new Integer(storeReg));
+ }
+
+ if ((seen == INVOKEVIRTUAL)
+ || (seen == INVOKESPECIAL)
+ || (seen == INVOKEINTERFACE)) {
+ String methodSig = getSigConstantOperand();
+ Type returnType = Type.getReturnType(methodSig);
+ if (!(returnType.equals(Type.VOID)) {
+ int parmCount = Type.getArgumentTypes(methodSig).length;
+ if (stack.getStackDepth() > parmCount) {
+ OpcodeStack.Item itm = stack.getStackItem(parmCount);
+ thisCallOccurred = (itm.getRegisterNumber() == 0);
+ } else
+ thisCallOccurred = false;
+ } else
+ thisCallOccurred = false;
+ }
+ else
+ thisCallOccurred = false;
+
if (seen == MONITORENTER) {
if (syncPC < 0) {
syncPC = getPC();
if (stack.getStackDepth() > 0) {
OpcodeStack.Item itm = stack.getStackItem(0);
- monitorReg = itm.getRegisterNumber();
+ int monitorReg = itm.getRegisterNumber();
+ if (monitorReg >= 0) {
+ unsafeAliases.add(new Integer(monitorReg));
+ }
}
}
}
@@ -95,7 +128,8 @@
else if (syncPC >= 0) {
boolean unsafe = ((seen == PUTFIELD) || (seen == GETFIELD));
unsafe |= (!isStatic) && ((seen == ALOAD_0) || (seen == ASTORE_0));
- unsafe |= (monitorReg >= 0) && (aloadReg(seen) == monitorReg);
+ int aloadReg = aloadReg(seen);
+ unsafe |= (aloadReg >= 0) && unsafeAliases.contains(new Integer(aloadReg));
if (unsafe) {
if ((getPC() - syncPC) > minSafeCodeLength) {
bugReporter.reportBug(new BugInstance(this, "BSB_BLOATED_SYNCHRONIZED_BLOCK", NORMAL_PRIORITY)
@@ -126,4 +160,19 @@
return seen - ALOAD_0;
return -1;
}
+
+ /**
+ * return the register number used in this ASTORE method, if it is an astore instruction
+ *
+ * @param seen the currently visited opcode
+ *
+ * @return the register used if it's an astore instruction, or -1 otherwise
+ */
+ public int astoreReg(int seen) {
+ if (seen == ASTORE)
+ return getRegisterOperand();
+ if ((seen >= ASTORE_0) && (seen <= ASTORE_3))
+ return seen - ASTORE_0;
+ return -1;
+ }
}
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