/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.dx.ssa;
import com.android.dx.rop.code.Exceptions;
import com.android.dx.rop.code.FillArrayDataInsn;
import com.android.dx.rop.code.Insn;
import com.android.dx.rop.code.PlainCstInsn;
import com.android.dx.rop.code.PlainInsn;
import com.android.dx.rop.code.RegOps;
import com.android.dx.rop.code.RegisterSpec;
import com.android.dx.rop.code.RegisterSpecList;
import com.android.dx.rop.code.Rop;
import com.android.dx.rop.code.Rops;
import com.android.dx.rop.code.ThrowingCstInsn;
import com.android.dx.rop.code.ThrowingInsn;
import com.android.dx.rop.cst.Constant;
import com.android.dx.rop.cst.CstLiteralBits;
import com.android.dx.rop.cst.CstMethodRef;
import com.android.dx.rop.cst.CstNat;
import com.android.dx.rop.cst.CstString;
import com.android.dx.rop.cst.CstType;
import com.android.dx.rop.cst.TypedConstant;
import com.android.dx.rop.cst.Zeroes;
import com.android.dx.rop.type.StdTypeList;
import com.android.dx.rop.type.Type;
import com.android.dx.rop.type.TypeBearer;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.HashSet;
import java.util.List;
/**
* Simple intraprocedural escape analysis. Finds new arrays that don't escape
* the method they are created in and replaces the array values with registers.
*/
public class EscapeAnalysis {
/**
* Struct used to generate and maintain escape analysis results.
*/
static class EscapeSet {
/** set containing all registers related to an object */
BitSet regSet;
/** escape state of the object */
EscapeState escape;
/** list of objects that are put into this object */
ArrayList<EscapeSet> childSets;
/** list of objects that this object is put into */
ArrayList<EscapeSet> parentSets;
/** flag to indicate this object is a scalar replaceable array */
boolean replaceableArray;
/**
* Constructs an instance of an EscapeSet
*
* @param reg the SSA register that defines the object
* @param size the number of registers in the method
* @param escState the lattice value to initially set this to
*/
EscapeSet(int reg, int size, EscapeState escState) {
regSet = new BitSet(size);
regSet.set(reg);
escape = escState;
childSets = new ArrayList<EscapeSet>();
parentSets = new ArrayList<EscapeSet>();
replaceableArray = false;
}
}
/**
* Lattice values used to indicate escape state for an object. Analysis can
* only raise escape state values, not lower them.
*
* TOP - Used for objects that haven't been analyzed yet
* NONE - Object does not escape, and is eligible for scalar replacement.
* METHOD - Object remains local to method, but can't be scalar replaced.
* INTER - Object is passed between methods. (treated as globally escaping
* since this is an intraprocedural analysis)
* GLOBAL - Object escapes globally.
*/
public enum EscapeState {
TOP, NONE, METHOD, INTER, GLOBAL
}
/** method we're processing */
private SsaMethod ssaMeth;
/** ssaMeth.getRegCount() */
private int regCount;
/** Lattice values for each object register group */
private ArrayList<EscapeSet> latticeValues;
/**
* Constructs an instance.
*
* @param ssaMeth method to process
*/
private EscapeAnalysis(SsaMethod ssaMeth) {
this.ssaMeth = ssaMeth;
this.regCount = ssaMeth.getRegCount();
this.latticeValues = new ArrayList<EscapeSet>();
}
/**
* Finds the index in the lattice for a particular register.
* Returns the size of the lattice if the register wasn't found.
*
* @param reg {@code non-null;} register being looked up
* @return index of the register or size of the lattice if it wasn't found.
*/
private int findSetIndex(RegisterSpec reg) {
int i;
for (i = 0; i < latticeValues.size(); i++) {
EscapeSet e = latticeValues.get(i);
if (e.regSet.get(reg.getReg())) {
return i;
}
}
return i;
}
/**
* Finds the corresponding instruction for a given move result
*
* @param moveInsn {@code non-null;} a move result instruction
* @return {@code non-null;} the instruction that produces the result for
* the move
*/
private SsaInsn getInsnForMove(SsaInsn moveInsn) {
int pred = moveInsn.getBlock().getPredecessors().nextSetBit(0);
ArrayList<SsaInsn> predInsns = ssaMeth.getBlocks().get(pred).getInsns();
return predInsns.get(predInsns.size()-1);
}
/**
* Finds the corresponding move result for a given instruction
*
* @param insn {@code non-null;} an instruction that must always be
* followed by a move result
* @return {@code non-null;} the move result for the given instruction
*/
private SsaInsn getMoveForInsn(SsaInsn insn) {
int succ = insn.getBlock().getSuccessors().nextSetBit(0);
ArrayList<SsaInsn> succInsns = ssaMeth.getBlocks().get(succ).getInsns();
return succInsns.get(0);
}
/**
* Creates a link in the lattice between two EscapeSets due to a put
* instruction. The object being put is the child and the object being put
* into is the parent. A child set must always have an escape state at
* least as high as its parent.
*
* @param parentSet {@code non-null;} the EscapeSet for the object being put
* into
* @param childSet {@code non-null;} the EscapeSet for the object being put
*/
private void addEdge(EscapeSet parentSet, EscapeSet childSet) {
if (!childSet.parentSets.contains(parentSet)) {
childSet.parentSets.add(parentSet);
}
if (!parentSet.childSets.contains(childSet)) {
parentSet.childSets.add(childSet);
}
}
/**
* Merges all links in the lattice among two EscapeSets. On return, the
* newNode will have its old links as well as all links from the oldNode.
* The oldNode has all its links removed.
*
* @param newNode {@code non-null;} the EscapeSet to merge all links into
* @param oldNode {@code non-null;} the EscapeSet to remove all links from
*/
private void replaceNode(EscapeSet newNode, EscapeSet oldNode) {
for (EscapeSet e : oldNode.parentSets) {
e.childSets.remove(oldNode);
e.childSets.add(newNode);
newNode.parentSets.add(e);
}
for (EscapeSet e : oldNode.childSets) {
e.parentSets.remove(oldNode);
e.parentSets.add(newNode);
newNode.childSets.add(e);
}
}
/**
* Performs escape analysis on a method. Finds scalar replaceable arrays and
* replaces them with equivalent registers.
*
* @param ssaMethod {@code non-null;} method to process
*/
public static void process(SsaMethod ssaMethod) {
new EscapeAnalysis(ssaMethod).run();
}
/**
* Process a single instruction, looking for new objects resulting from
* move result or move param.
*
* @param insn {@code non-null;} instruction to process
*/
private void processInsn(SsaInsn insn) {
int op = insn.getOpcode().getOpcode();
RegisterSpec result = insn.getResult();
EscapeSet escSet;
// Identify new objects
if (op == RegOps.MOVE_RESULT_PSEUDO &&
result.getTypeBearer().getBasicType() == Type.BT_OBJECT) {
// Handle objects generated through move_result_pseudo
escSet = processMoveResultPseudoInsn(insn);
processRegister(result, escSet);
} else if (op == RegOps.MOVE_PARAM &&
result.getTypeBearer().getBasicType() == Type.BT_OBJECT) {
// Track method arguments that are objects
escSet = new EscapeSet(result.getReg(), regCount, EscapeState.NONE);
latticeValues.add(escSet);
processRegister(result, escSet);
} else if (op == RegOps.MOVE_RESULT &&
result.getTypeBearer().getBasicType() == Type.BT_OBJECT) {
// Track method return values that are objects
escSet = new EscapeSet(result.getReg(), regCount, EscapeState.NONE);
latticeValues.add(escSet);
processRegister(result, escSet);
}
}
/**
* Determine the origin of a move result pseudo instruction that generates
* an object. Creates a new EscapeSet for the new object accordingly.
*
* @param insn {@code non-null;} move result pseudo instruction to process
* @return {@code non-null;} an EscapeSet for the object referred to by the
* move result pseudo instruction
*/
private EscapeSet processMoveResultPseudoInsn(SsaInsn insn) {
RegisterSpec result = insn.getResult();
SsaInsn prevSsaInsn = getInsnForMove(insn);
int prevOpcode = prevSsaInsn.getOpcode().getOpcode();
EscapeSet escSet;
RegisterSpec prevSource;
switch(prevOpcode) {
// New instance / Constant
case RegOps.NEW_INSTANCE:
case RegOps.CONST:
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.NONE);
break;
// New array
case RegOps.NEW_ARRAY:
case RegOps.FILLED_NEW_ARRAY:
prevSource = prevSsaInsn.getSources().get(0);
if (prevSource.getTypeBearer().isConstant()) {
// New fixed array
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.NONE);
escSet.replaceableArray = true;
} else {
// New variable array
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.GLOBAL);
}
break;
// Loading a static object
case RegOps.GET_STATIC:
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.GLOBAL);
break;
// Type cast / load an object from a field or array
case RegOps.CHECK_CAST:
case RegOps.GET_FIELD:
case RegOps.AGET:
prevSource = prevSsaInsn.getSources().get(0);
int setIndex = findSetIndex(prevSource);
// Set should already exist, try to find it
if (setIndex != latticeValues.size()) {
escSet = latticeValues.get(setIndex);
escSet.regSet.set(result.getReg());
return escSet;
}
// Set not found, must be either null or unknown
if (prevSource.getType() == Type.KNOWN_NULL) {
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.NONE);
} else {
escSet = new EscapeSet(result.getReg(), regCount,
EscapeState.GLOBAL);
}
break;
default:
return null;
}
// Add the newly created escSet to the lattice and return it
latticeValues.add(escSet);
return escSet;
}
/**
* Iterate through all the uses of a new object.
*
* @param result {@code non-null;} register where new object is stored
* @param escSet {@code non-null;} EscapeSet for the new object
*/
private void processRegister(RegisterSpec result, EscapeSet escSet) {
ArrayList<RegisterSpec> regWorklist = new ArrayList<RegisterSpec>();
regWorklist.add(result);
// Go through the worklist
while (!regWorklist.isEmpty()) {
int listSize = regWorklist.size() - 1;
RegisterSpec def = regWorklist.remove(listSize);
List<SsaInsn> useList = ssaMeth.getUseListForRegister(def.getReg());
// Handle all the uses of this register
for (SsaInsn use : useList) {
Rop useOpcode = use.getOpcode();
if (useOpcode == null) {
// Handle phis
processPhiUse(use, escSet, regWorklist);
} else {
// Handle other opcodes
processUse(def, use, escSet, regWorklist);
}
}
}
}
/**
* Handles phi uses of new objects. Will merge together the sources of a phi
* into a single EscapeSet. Adds the result of the phi to the worklist so
* its uses can be followed.
*
* @param use {@code non-null;} phi use being processed
* @param escSet {@code non-null;} EscapeSet for the object
* @param regWorklist {@code non-null;} worklist of instructions left to
* process for this object
*/
private void processPhiUse(SsaInsn use, EscapeSet escSet,
ArrayList<RegisterSpec> regWorklist) {
int setIndex = findSetIndex(use.getResult());
if (setIndex != latticeValues.size()) {
// Check if result is in a set already
EscapeSet mergeSet = latticeValues.get(setIndex);
if (mergeSet != escSet) {
// If it is, merge the sets and states, then delete the copy
escSet.replaceableArray = false;
escSet.regSet.or(mergeSet.regSet);
if (escSet.escape.compareTo(mergeSet.escape) < 0) {
escSet.escape = mergeSet.escape;
}
replaceNode(escSet, mergeSet);
latticeValues.remove(setIndex);
}
} else {
// If no set is found, add it to this escSet and the worklist
escSet.regSet.set(use.getResult().getReg());
regWorklist.add(use.getResult());
}
}
/**
* Handles non-phi uses of new objects. Checks to see how instruction is
* used and updates the escape state accordingly.
*
* @param def {@code non-null;} register holding definition of new object
* @param use {@code non-null;} use of object being processed
* @param escSet {@code non-null;} EscapeSet for the object
* @param regWorklist {@code non-null;} worklist of instructions left to
* process for this object
*/
private void processUse(RegisterSpec def, SsaInsn use, EscapeSet escSet,
ArrayList<RegisterSpec> regWorklist) {
int useOpcode = use.getOpcode().getOpcode();
switch (useOpcode) {
case RegOps.MOVE:
// Follow uses of the move by adding it to the worklist
escSet.regSet.set(use.getResult().getReg());
regWorklist.add(use.getResult());
break;
case RegOps.IF_EQ:
case RegOps.IF_NE:
case RegOps.CHECK_CAST:
// Compared objects can't be replaced, so promote if necessary
if (escSet.escape.compareTo(EscapeState.METHOD) < 0) {
escSet.escape = EscapeState.METHOD;
}
break;
case RegOps.APUT:
// For array puts, check for a constant array index
RegisterSpec putIndex = use.getSources().get(2);
if (!putIndex.getTypeBearer().isConstant()) {
// If not constant, array can't be replaced
escSet.replaceableArray = false;
}
// Intentional fallthrough
case RegOps.PUT_FIELD:
// Skip non-object puts
RegisterSpec putValue = use.getSources().get(0);
if (putValue.getTypeBearer().getBasicType() != Type.BT_OBJECT) {
break;
}
escSet.replaceableArray = false;
// Raise 1st object's escape state to 2nd if 2nd is higher
RegisterSpecList sources = use.getSources();
if (sources.get(0).getReg() == def.getReg()) {
int setIndex = findSetIndex(sources.get(1));
if (setIndex != latticeValues.size()) {
EscapeSet parentSet = latticeValues.get(setIndex);
addEdge(parentSet, escSet);
if (escSet.escape.compareTo(parentSet.escape) < 0) {
escSet.escape = parentSet.escape;
}
}
} else {
int setIndex = findSetIndex(sources.get(0));
if (setIndex != latticeValues.size()) {
EscapeSet childSet = latticeValues.get(setIndex);
addEdge(escSet, childSet);
if (childSet.escape.compareTo(escSet.escape) < 0) {
childSet.escape = escSet.escape;
}
}
}
break;
case RegOps.AGET:
// For array gets, check for a constant array index
RegisterSpec getIndex = use.getSources().get(1);
if (!getIndex.getTypeBearer().isConstant()) {
// If not constant, array can't be replaced
escSet.replaceableArray = false;
}
break;
case RegOps.PUT_STATIC:
// Static puts cause an object to escape globally
escSet.escape = EscapeState.GLOBAL;
break;
case RegOps.INVOKE_STATIC:
case RegOps.INVOKE_VIRTUAL:
case RegOps.INVOKE_SUPER:
case RegOps.INVOKE_DIRECT:
case RegOps.INVOKE_INTERFACE:
case RegOps.RETURN:
case RegOps.THROW:
// These operations cause an object to escape interprocedurally
escSet.escape = EscapeState.INTER;
break;
default:
break;
}
}
/**
* Performs scalar replacement on all eligible arrays.
*/
private void scalarReplacement() {
// Iterate through lattice, looking for non-escaping replaceable arrays
for (EscapeSet escSet : latticeValues) {
if (!escSet.replaceableArray || escSet.escape != EscapeState.NONE) {
continue;
}
// Get the instructions for the definition and move of the array
int e = escSet.regSet.nextSetBit(0);
SsaInsn def = ssaMeth.getDefinitionForRegister(e);
SsaInsn prev = getInsnForMove(def);
// Create a map for the new registers that will be created
TypeBearer lengthReg = prev.getSources().get(0).getTypeBearer();
int length = ((CstLiteralBits) lengthReg).getIntBits();
ArrayList<RegisterSpec> newRegs =
new ArrayList<RegisterSpec>(length);
HashSet<SsaInsn> deletedInsns = new HashSet<SsaInsn>();
// Replace the definition of the array with registers
replaceDef(def, prev, length, newRegs);
// Mark definition instructions for deletion
deletedInsns.add(prev);
deletedInsns.add(def);
// Go through all uses of the array
List<SsaInsn> useList = ssaMeth.getUseListForRegister(e);
for (SsaInsn use : useList) {
// Replace the use with scalars and then mark it for deletion
replaceUse(use, prev, newRegs, deletedInsns);
deletedInsns.add(use);
}
// Delete all marked instructions
ssaMeth.deleteInsns(deletedInsns);
ssaMeth.onInsnsChanged();
// Convert the method back to SSA form
SsaConverter.updateSsaMethod(ssaMeth, regCount);
// Propagate and remove extra moves added by scalar replacement
movePropagate();
}
}
/**
* Replaces the instructions that define an array with equivalent registers.
* For each entry in the array, a register is created, initialized to zero.
* A mapping between this register and the corresponding array index is
* added.
*
* @param def {@code non-null;} move result instruction for array
* @param prev {@code non-null;} instruction for instantiating new array
* @param length size of the new array
* @param newRegs {@code non-null;} mapping of array indices to new
* registers to be populated
*/
private void replaceDef(SsaInsn def, SsaInsn prev, int length,
ArrayList<RegisterSpec> newRegs) {
Type resultType = def.getResult().getType();
// Create new zeroed out registers for each element in the array
for (int i = 0; i < length; i++) {
Constant newZero = Zeroes.zeroFor(resultType.getComponentType());
TypedConstant typedZero = (TypedConstant) newZero;
RegisterSpec newReg =
RegisterSpec.make(ssaMeth.makeNewSsaReg(), typedZero);
newRegs.add(newReg);
insertPlainInsnBefore(def, RegisterSpecList.EMPTY, newReg,
RegOps.CONST, newZero);
}
}
/**
* Replaces the use for a scalar replaceable array. Gets and puts become
* move instructions, and array lengths and fills are handled. Can also
* identify ArrayIndexOutOfBounds exceptions and throw them if detected.
*
* @param use {@code non-null;} move result instruction for array
* @param prev {@code non-null;} instruction for instantiating new array
* @param newRegs {@code non-null;} mapping of array indices to new
* registers
* @param deletedInsns {@code non-null;} set of instructions marked for
* deletion
*/
private void replaceUse(SsaInsn use, SsaInsn prev,
ArrayList<RegisterSpec> newRegs,
HashSet<SsaInsn> deletedInsns) {
int index;
int length = newRegs.size();
SsaInsn next;
RegisterSpecList sources;
RegisterSpec source, result;
CstLiteralBits indexReg;
switch (use.getOpcode().getOpcode()) {
case RegOps.AGET:
// Replace array gets with moves
next = getMoveForInsn(use);
sources = use.getSources();
indexReg = ((CstLiteralBits) sources.get(1).getTypeBearer());
index = indexReg.getIntBits();
if (index < length) {
source = newRegs.get(index);
result = source.withReg(next.getResult().getReg());
insertPlainInsnBefore(next, RegisterSpecList.make(source),
result, RegOps.MOVE, null);
} else {
// Throw an exception if the index is out of bounds
insertExceptionThrow(next, sources.get(1), deletedInsns);
deletedInsns.add(next.getBlock().getInsns().get(2));
}
deletedInsns.add(next);
break;
case RegOps.APUT:
// Replace array puts with moves
sources = use.getSources();
indexReg = ((CstLiteralBits) sources.get(2).getTypeBearer());
index = indexReg.getIntBits();
if (index < length) {
source = sources.get(0);
result = source.withReg(newRegs.get(index).getReg());
insertPlainInsnBefore(use, RegisterSpecList.make(source),
result, RegOps.MOVE, null);
// Update the newReg entry to mark value as unknown now
newRegs.set(index, result.withSimpleType());
} else {
// Throw an exception if the index is out of bounds
insertExceptionThrow(use, sources.get(2), deletedInsns);
}
break;
case RegOps.ARRAY_LENGTH:
// Replace array lengths with const instructions
TypeBearer lengthReg = prev.getSources().get(0).getTypeBearer();
//CstInteger lengthReg = CstInteger.make(length);
next = getMoveForInsn(use);
insertPlainInsnBefore(next, RegisterSpecList.EMPTY,
next.getResult(), RegOps.CONST,
(Constant) lengthReg);
deletedInsns.add(next);
break;
case RegOps.MARK_LOCAL:
// Remove mark local instructions
break;
case RegOps.FILL_ARRAY_DATA:
// Create const instructions for each fill value
Insn ropUse = use.getOriginalRopInsn();
FillArrayDataInsn fill = (FillArrayDataInsn) ropUse;
ArrayList<Constant> constList = fill.getInitValues();
for (int i = 0; i < length; i++) {
RegisterSpec newFill =
RegisterSpec.make(newRegs.get(i).getReg(),
(TypeBearer) constList.get(i));
insertPlainInsnBefore(use, RegisterSpecList.EMPTY, newFill,
RegOps.CONST, constList.get(i));
// Update the newRegs to hold the new const value
newRegs.set(i, newFill);
}
break;
default:
}
}
/**
* Identifies extra moves added by scalar replacement and propagates the
* source of the move to any users of the result.
*/
private void movePropagate() {
for (int i = 0; i < ssaMeth.getRegCount(); i++) {
SsaInsn insn = ssaMeth.getDefinitionForRegister(i);
// Look for move instructions only
if (insn == null || insn.getOpcode() == null ||
insn.getOpcode().getOpcode() != RegOps.MOVE) {
continue;
}
final ArrayList<SsaInsn>[] useList = ssaMeth.getUseListCopy();
final RegisterSpec source = insn.getSources().get(0);
final RegisterSpec result = insn.getResult();
// Ignore moves that weren't added due to scalar replacement
if (source.getReg() < regCount && result.getReg() < regCount) {
continue;
}
// Create a mapping from source to result
RegisterMapper mapper = new RegisterMapper() {
@Override
public int getNewRegisterCount() {
return ssaMeth.getRegCount();
}
@Override
public RegisterSpec map(RegisterSpec registerSpec) {
if (registerSpec.getReg() == result.getReg()) {
return source;
}
return registerSpec;
}
};
// Modify all uses of the move to use the source of the move instead
for (SsaInsn use : useList[result.getReg()]) {
use.mapSourceRegisters(mapper);
}
}
}
/**
* Runs escape analysis and scalar replacement of arrays.
*/
private void run() {
ssaMeth.forEachBlockDepthFirstDom(new SsaBasicBlock.Visitor() {
public void visitBlock (SsaBasicBlock block,
SsaBasicBlock unused) {
block.forEachInsn(new SsaInsn.Visitor() {
public void visitMoveInsn(NormalSsaInsn insn) {
// do nothing
}
public void visitPhiInsn(PhiInsn insn) {
// do nothing
}
public void visitNonMoveInsn(NormalSsaInsn insn) {
processInsn(insn);
}
});
}
});
// Go through lattice and promote fieldSets as necessary
for (EscapeSet e : latticeValues) {
if (e.escape != EscapeState.NONE) {
for (EscapeSet field : e.childSets) {
if (e.escape.compareTo(field.escape) > 0) {
field.escape = e.escape;
}
}
}
}
// Perform scalar replacement for arrays
scalarReplacement();
}
/**
* Replaces instructions that trigger an ArrayIndexOutofBounds exception
* with an actual throw of the exception.
*
* @param insn {@code non-null;} instruction causing the exception
* @param index {@code non-null;} index value that is out of bounds
* @param deletedInsns {@code non-null;} set of instructions marked for
* deletion
*/
private void insertExceptionThrow(SsaInsn insn, RegisterSpec index,
HashSet<SsaInsn> deletedInsns) {
// Create a new ArrayIndexOutOfBoundsException
CstType exception =
new CstType(Exceptions.TYPE_ArrayIndexOutOfBoundsException);
insertThrowingInsnBefore(insn, RegisterSpecList.EMPTY, null,
RegOps.NEW_INSTANCE, exception);
// Add a successor block with a move result pseudo for the exception
SsaBasicBlock currBlock = insn.getBlock();
SsaBasicBlock newBlock =
currBlock.insertNewSuccessor(currBlock.getPrimarySuccessor());
SsaInsn newInsn = newBlock.getInsns().get(0);
RegisterSpec newReg =
RegisterSpec.make(ssaMeth.makeNewSsaReg(), exception);
insertPlainInsnBefore(newInsn, RegisterSpecList.EMPTY, newReg,
RegOps.MOVE_RESULT_PSEUDO, null);
// Add another successor block to initialize the exception
SsaBasicBlock newBlock2 =
newBlock.insertNewSuccessor(newBlock.getPrimarySuccessor());
SsaInsn newInsn2 = newBlock2.getInsns().get(0);
CstNat newNat = new CstNat(new CstString("<init>"), new CstString("(I)V"));
CstMethodRef newRef = new CstMethodRef(exception, newNat);
insertThrowingInsnBefore(newInsn2, RegisterSpecList.make(newReg, index),
null, RegOps.INVOKE_DIRECT, newRef);
deletedInsns.add(newInsn2);
// Add another successor block to throw the new exception
SsaBasicBlock newBlock3 =
newBlock2.insertNewSuccessor(newBlock2.getPrimarySuccessor());
SsaInsn newInsn3 = newBlock3.getInsns().get(0);
insertThrowingInsnBefore(newInsn3, RegisterSpecList.make(newReg), null,
RegOps.THROW, null);
newBlock3.replaceSuccessor(newBlock3.getPrimarySuccessorIndex(),
ssaMeth.getExitBlock().getIndex());
deletedInsns.add(newInsn3);
}
/**
* Inserts a new PlainInsn before the given instruction.
* TODO: move this somewhere more appropriate
*
* @param insn {@code non-null;} instruction to insert before
* @param newSources {@code non-null;} sources of new instruction
* @param newResult {@code non-null;} result of new instruction
* @param newOpcode opcode of new instruction
* @param cst {@code null-ok;} constant for new instruction, if any
*/
private void insertPlainInsnBefore(SsaInsn insn,
RegisterSpecList newSources, RegisterSpec newResult, int newOpcode,
Constant cst) {
Insn originalRopInsn = insn.getOriginalRopInsn();
Rop newRop;
if (newOpcode == RegOps.MOVE_RESULT_PSEUDO) {
newRop = Rops.opMoveResultPseudo(newResult.getType());
} else {
newRop = Rops.ropFor(newOpcode, newResult, newSources, cst);
}
Insn newRopInsn;
if (cst == null) {
newRopInsn = new PlainInsn(newRop,
originalRopInsn.getPosition(), newResult, newSources);
} else {
newRopInsn = new PlainCstInsn(newRop,
originalRopInsn.getPosition(), newResult, newSources, cst);
}
NormalSsaInsn newInsn = new NormalSsaInsn(newRopInsn, insn.getBlock());
List<SsaInsn> insns = insn.getBlock().getInsns();
insns.add(insns.lastIndexOf(insn), newInsn);
ssaMeth.onInsnAdded(newInsn);
}
/**
* Inserts a new ThrowingInsn before the given instruction.
* TODO: move this somewhere more appropriate
*
* @param insn {@code non-null;} instruction to insert before
* @param newSources {@code non-null;} sources of new instruction
* @param newResult {@code non-null;} result of new instruction
* @param newOpcode opcode of new instruction
* @param cst {@code null-ok;} constant for new instruction, if any
*/
private void insertThrowingInsnBefore(SsaInsn insn,
RegisterSpecList newSources, RegisterSpec newResult, int newOpcode,
Constant cst) {
Insn origRopInsn = insn.getOriginalRopInsn();
Rop newRop = Rops.ropFor(newOpcode, newResult, newSources, cst);
Insn newRopInsn;
if (cst == null) {
newRopInsn = new ThrowingInsn(newRop,
origRopInsn.getPosition(), newSources, StdTypeList.EMPTY);
} else {
newRopInsn = new ThrowingCstInsn(newRop,
origRopInsn.getPosition(), newSources, StdTypeList.EMPTY, cst);
}
NormalSsaInsn newInsn = new NormalSsaInsn(newRopInsn, insn.getBlock());
List<SsaInsn> insns = insn.getBlock().getInsns();
insns.add(insns.lastIndexOf(insn), newInsn);
ssaMeth.onInsnAdded(newInsn);
}
}
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