DASCA
/
WALA
2
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

comments and formatting 

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@3523 f5eafffb-2e1d-0410-98e4-8ec43c5233c4
This commit is contained in:
sjfink 2009-04-22 19:12:11 +00:00
parent 3fb8781d9d
commit 565532c7ff
1 changed files with 33 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
com.ibm.wala.core/src/com/ibm/wala/analysis/stackMachine/AbstractIntStackMachine.java
View File

@ -58,18 +58,11 @@ import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.shrike.ShrikeUtil;
/**
*
* Skeleton of functionality to propagate information through the Java bytecode
* stack machine using ShrikeBT.
*
* This class computes properties the Java operand stack and of the local
* variables at the beginning of each basic block.
*
* In this implementation, each dataflow variable value is an integer, and the
* "meeter" object provides the meets
*
* @author sfink
* @author roca (some code stolen from ShrikeBT verifier)
* Skeleton of functionality to propagate information through the Java bytecode stack machine using ShrikeBT.
* <p>
* This class computes properties the Java operand stack and of the local variables at the beginning of each basic block.
* <p>
* In this implementation, each dataflow variable value is an integer, and the "meeter" object provides the meets
*/
public abstract class AbstractIntStackMachine implements FixedPointConstants {
@ -104,8 +97,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
final protected int maxLocals;
/**
* Should uninitialized variables be considered TOP (optimistic) or BOTTOM
* (pessimistic);
* Should uninitialized variables be considered TOP (optimistic) or BOTTOM (pessimistic);
*/
final public static boolean OPTIMISTIC = true;
@ -320,45 +312,34 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
}
/**
* A Meeter object provides the dataflow logic needed to meet the abstract
* machine state for a dataflow meet.
* A Meeter object provides the dataflow logic needed to meet the abstract machine state for a dataflow meet.
*/
protected interface Meeter {
/**
* Return the integer that represents the meet of a particular stack slot at
* the entry to a basic block.
* Return the integer that represents the meet of a particular stack slot at the entry to a basic block.
*
* @param slot
* The stack slot to meet
* @param rhs
* The values to meet
* @param bb
* The basic block at whose entry this meet occurs
* @param slot The stack slot to meet
* @param rhs The values to meet
* @param bb The basic block at whose entry this meet occurs
* @return The value result of the meet
*/
int meetStack(int slot, int[] rhs, BasicBlock bb);
/**
* Return the integer that represents stack slot 0 after a meet at the entry
* to a catch block.
* Return the integer that represents stack slot 0 after a meet at the entry to a catch block.
*
* @param bb
* The basic block at whose entry this meet occurs
* @param bb The basic block at whose entry this meet occurs
* @return The value of stack slot 0 after the meet
*/
int meetStackAtCatchBlock(BasicBlock bb);
/**
* Return the integer that represents the meet of a particular local at the
* entry to a basic block.
* Return the integer that represents the meet of a particular local at the entry to a basic block.
*
* @param n
* The number of the local
* @param rhs
* The values to meet
* @param bb
* The basic block at whose entry this meet occurs
* @param n The number of the local
* @param rhs The values to meet
* @param bb The basic block at whose entry this meet occurs
* @return The value of local n after the meet.
*/
int meetLocal(int n, int[] rhs, BasicBlock bb);
@ -369,8 +350,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
*
* TODO: add some efficiency shortcuts. TODO: clean up and refactor.
*
* @param bb
* the basic block at whose entry the meet occurs
* @param bb the basic block at whose entry the meet occurs
* @return true if the lhs value changes. false otherwise.
*/
private boolean meet(IVariable lhs, IVariable[] rhs, BasicBlock bb, Meeter meeter) {
@ -386,8 +366,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
*
* TODO: add some efficiency shortcuts. TODO: clean up and refactor.
*
* @param bb
* the basic block at whose entry the meet occurs
* @param bb the basic block at whose entry the meet occurs
* @return true if the lhs value changes. false otherwise.
*/
private boolean meetForCatchBlock(IVariable lhs, IVariable[] rhs, BasicBlock bb, Meeter meeter) {
@ -398,13 +377,11 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
}
/**
* Evaluate a meet of the stacks of machine states at the entry of a catch
* block.
* Evaluate a meet of the stacks of machine states at the entry of a catch block.
*
* TODO: add some efficiency shortcuts. TODO: clean up and refactor.
*
* @param bb
* the basic block at whose entry the meet occurs
* @param bb the basic block at whose entry the meet occurs
* @return true if the lhs value changes. false otherwise.
*/
private boolean meetStacksAtCatchBlock(IVariable lhs, BasicBlock bb, Meeter meeter) {
@ -435,13 +412,11 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
}
/**
* Evaluate a meet of the stacks of machine states at the entry of a basic
* block.
* Evaluate a meet of the stacks of machine states at the entry of a basic block.
*
* TODO: add some efficiency shortcuts. TODO: clean up and refactor.
*
* @param bb
* the basic block at whose entry the meet occurs
* @param bb the basic block at whose entry the meet occurs
* @return true if the lhs value changes. false otherwise.
*/
private boolean meetStacks(IVariable lhs, IVariable[] rhs, BasicBlock bb, Meeter meeter) {
@ -494,8 +469,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
*
* TODO: add some efficiency shortcuts. TODO: clean up and refactor.
*
* @param bb
* the basic block at whose entry the meet occurs
* @param bb the basic block at whose entry the meet occurs
* @return true if the lhs value changes. false otherwise.
*/
private boolean meetLocals(IVariable lhs, IVariable[] rhs, BasicBlock bb, Meeter meeter) {
@ -529,10 +503,8 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
}
/**
* @return the number of locals to meet. Return -1 if there is no local meet
* necessary.
* @param operands
* The operands for this operator. operands[0] is the left-hand side.
* @return the number of locals to meet. Return -1 if there is no local meet necessary.
* @param operands The operands for this operator. operands[0] is the left-hand side.
*/
private static int computeMeetNLocals(IVariable[] operands) {
MachineState lhs = (MachineState) operands[0];
@ -552,10 +524,8 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
}
/**
* @return the height of stacks that are being meeted. Return -1 if there is
* no stack meet necessary.
* @param operands
* The operands for this operator. operands[0] is the left-hand side.
* @return the height of stacks that are being meeted. Return -1 if there is no stack meet necessary.
* @param operands The operands for this operator. operands[0] is the left-hand side.
*/
private static int computeMeetStackHeight(IVariable[] operands) {
MachineState lhs = (MachineState) operands[0];
@ -588,8 +558,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
private final BasicBlock bb;
/**
* I'm not using clone because I don't want to necessarily inherit the
* AbstractVariable state from the superclass
* I'm not using clone because I don't want to necessarily inherit the AbstractVariable state from the superclass
*/
public MachineState duplicate() {
MachineState result = new MachineState(bb);
@ -799,7 +768,7 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
public int getStackHeight() {
return stackHeight;
}
/**
* Use with care.
*/
@ -827,21 +796,18 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
public boolean needsEdgeFlow();
/**
* Compute the MachineState at the exit of a basic block, given a
* MachineState at the block's entry.
* Compute the MachineState at the exit of a basic block, given a MachineState at the block's entry.
*/
public MachineState flow(MachineState entry, BasicBlock basicBlock);
/**
* Compute the MachineState at the end of an edge, given a MachineState at
* the edges's entry.
* Compute the MachineState at the end of an edge, given a MachineState at the edges's entry.
*/
public MachineState flow(MachineState entry, BasicBlock from, BasicBlock to);
}
/**
* This gives some basic facilities for shoving things around on the stack.
* Client analyses should subclass this as needed.
* This gives some basic facilities for shoving things around on the stack. Client analyses should subclass this as needed.
*/
protected static abstract class BasicStackFlowProvider implements FlowProvider, Constants {
private final ShrikeCFG cfg;
@ -934,7 +900,6 @@ public abstract class AbstractIntStackMachine implements FixedPointConstants {
return currentSuccessorBlock;
}
public abstract IInstruction[] getInstructions();
/**