/*
* Copyright (C) 2007 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.rop.code;
import com.android.dx.rop.type.StdTypeList;
import com.android.dx.rop.type.TypeList;
import com.android.dx.util.Hex;
import com.android.dx.util.IntList;
import com.android.dx.util.LabeledList;
/**
* List of {@link BasicBlock} instances.
*/
public final class BasicBlockList extends LabeledList {
/**
* {@code >= -1;} the count of registers required by this method or
* {@code -1} if not yet calculated
*/
private int regCount;
/**
* Constructs an instance. All indices initially contain {@code null},
* and the first-block label is initially {@code -1}.
*
* @param size the size of the list
*/
public BasicBlockList(int size) {
super(size);
regCount = -1;
}
/**
* Constructs a mutable copy for {@code getMutableCopy()}.
*
* @param old block to copy
*/
private BasicBlockList (BasicBlockList old) {
super(old);
regCount = old.regCount;
}
/**
* Gets the element at the given index. It is an error to call
* this with the index for an element which was never set; if you
* do that, this will throw {@code NullPointerException}.
*
* @param n {@code >= 0, < size();} which index
* @return {@code non-null;} element at that index
*/
public BasicBlock get(int n) {
return (BasicBlock) get0(n);
}
/**
* Sets the basic block at the given index.
*
* @param n {@code >= 0, < size();} which index
* @param bb {@code null-ok;} the element to set at {@code n}
*/
public void set(int n, BasicBlock bb) {
super.set(n, bb);
// Reset regCount, since it will need to be recalculated.
regCount = -1;
}
/**
* Returns how many registers this method requires. This is simply
* the maximum of register-number-plus-category referred to by this
* instance's instructions (indirectly through {@link BasicBlock}
* instances).
*
* @return {@code >= 0;} the register count
*/
public int getRegCount() {
if (regCount == -1) {
RegCountVisitor visitor = new RegCountVisitor();
forEachInsn(visitor);
regCount = visitor.getRegCount();
}
return regCount;
}
/**
* Gets the total instruction count for this instance. This is the
* sum of the instruction counts of each block.
*
* @return {@code >= 0;} the total instruction count
*/
public int getInstructionCount() {
int sz = size();
int result = 0;
for (int i = 0; i < sz; i++) {
BasicBlock one = (BasicBlock) getOrNull0(i);
if (one != null) {
result += one.getInsns().size();
}
}
return result;
}
/**
* Gets the total instruction count for this instance, ignoring
* mark-local instructions which are not actually emitted.
*
* @return {@code >= 0;} the total instruction count
*/
public int getEffectiveInstructionCount() {
int sz = size();
int result = 0;
for (int i = 0; i < sz; i++) {
BasicBlock one = (BasicBlock) getOrNull0(i);
if (one != null) {
InsnList insns = one.getInsns();
int insnsSz = insns.size();
for (int j = 0; j < insnsSz; j++) {
Insn insn = insns.get(j);
if (insn.getOpcode().getOpcode() != RegOps.MARK_LOCAL) {
result++;
}
}
}
}
return result;
}
/**
* Gets the first block in the list with the given label, if any.
*
* @param label {@code >= 0;} the label to look for
* @return {@code non-null;} the so-labelled block
* @throws IllegalArgumentException thrown if the label isn't found
*/
public BasicBlock labelToBlock(int label) {
int idx = indexOfLabel(label);
if (idx < 0) {
throw new IllegalArgumentException("no such label: "
+ Hex.u2(label));
}
return get(idx);
}
/**
* Visits each instruction of each block in the list, in order.
*
* @param visitor {@code non-null;} visitor to use
*/
public void forEachInsn(Insn.Visitor visitor) {
int sz = size();
for (int i = 0; i < sz; i++) {
BasicBlock one = get(i);
InsnList insns = one.getInsns();
insns.forEach(visitor);
}
}
/**
* Returns an instance that is identical to this one, except that
* the registers in each instruction are offset by the given
* amount. Mutability of the result is inherited from the
* original.
*
* @param delta the amount to offset register numbers by
* @return {@code non-null;} an appropriately-constructed instance
*/
public BasicBlockList withRegisterOffset(int delta) {
int sz = size();
BasicBlockList result = new BasicBlockList(sz);
for (int i = 0; i < sz; i++) {
BasicBlock one = (BasicBlock) get0(i);
if (one != null) {
result.set(i, one.withRegisterOffset(delta));
}
}
if (isImmutable()) {
result.setImmutable();
}
return result;
}
/**
* Returns a mutable copy of this list.
*
* @return {@code non-null;} an appropriately-constructed instance
*/
public BasicBlockList getMutableCopy() {
return new BasicBlockList(this);
}
/**
* Gets the preferred successor for the given block. If the block
* only has one successor, then that is the preferred successor.
* Otherwise, if the block has a primay successor, then that is
* the preferred successor. If the block has no successors, then
* this returns {@code null}.
*
* @param block {@code non-null;} the block in question
* @return {@code null-ok;} the preferred successor, if any
*/
public BasicBlock preferredSuccessorOf(BasicBlock block) {
int primarySuccessor = block.getPrimarySuccessor();
IntList successors = block.getSuccessors();
int succSize = successors.size();
switch (succSize) {
case 0: {
return null;
}
case 1: {
return labelToBlock(successors.get(0));
}
}
if (primarySuccessor != -1) {
return labelToBlock(primarySuccessor);
} else {
return labelToBlock(successors.get(0));
}
}
/**
* Compares the catches of two blocks for equality. This includes
* both the catch types and target labels.
*
* @param block1 {@code non-null;} one block to compare
* @param block2 {@code non-null;} the other block to compare
* @return {@code true} if the two blocks' non-primary successors
* are identical
*/
public boolean catchesEqual(BasicBlock block1,
BasicBlock block2) {
TypeList catches1 = block1.getExceptionHandlerTypes();
TypeList catches2 = block2.getExceptionHandlerTypes();
if (!StdTypeList.equalContents(catches1, catches2)) {
return false;
}
IntList succ1 = block1.getSuccessors();
IntList succ2 = block2.getSuccessors();
int size = succ1.size(); // Both are guaranteed to be the same size.
int primary1 = block1.getPrimarySuccessor();
int primary2 = block2.getPrimarySuccessor();
if (((primary1 == -1) || (primary2 == -1))
&& (primary1 != primary2)) {
/*
* For the current purpose, both blocks in question must
* either both have a primary or both not have a primary to
* be considered equal, and it turns out here that that's not
* the case.
*/
return false;
}
for (int i = 0; i < size; i++) {
int label1 = succ1.get(i);
int label2 = succ2.get(i);
if (label1 == primary1) {
/*
* It should be the case that block2's primary is at the
* same index. If not, we consider the blocks unequal for
* the current purpose.
*/
if (label2 != primary2) {
return false;
}
continue;
}
if (label1 != label2) {
return false;
}
}
return true;
}
/**
* Instruction visitor class for counting registers used.
*/
private static class RegCountVisitor
implements Insn.Visitor {
/** {@code >= 0;} register count in-progress */
private int regCount;
/**
* Constructs an instance.
*/
public RegCountVisitor() {
regCount = 0;
}
/**
* Gets the register count.
*
* @return {@code >= 0;} the count
*/
public int getRegCount() {
return regCount;
}
/** {@inheritDoc} */
public void visitPlainInsn(PlainInsn insn) {
visit(insn);
}
/** {@inheritDoc} */
public void visitPlainCstInsn(PlainCstInsn insn) {
visit(insn);
}
/** {@inheritDoc} */
public void visitSwitchInsn(SwitchInsn insn) {
visit(insn);
}
/** {@inheritDoc} */
public void visitThrowingCstInsn(ThrowingCstInsn insn) {
visit(insn);
}
/** {@inheritDoc} */
public void visitThrowingInsn(ThrowingInsn insn) {
visit(insn);
}
/** {@inheritDoc} */
public void visitFillArrayDataInsn(FillArrayDataInsn insn) {
visit(insn);
}
/**
* Helper for all the {@code visit*} methods.
*
* @param insn {@code non-null;} instruction being visited
*/
private void visit(Insn insn) {
RegisterSpec result = insn.getResult();
if (result != null) {
processReg(result);
}
RegisterSpecList sources = insn.getSources();
int sz = sources.size();
for (int i = 0; i < sz; i++) {
processReg(sources.get(i));
}
}
/**
* Processes the given register spec.
*
* @param spec {@code non-null;} the register spec
*/
private void processReg(RegisterSpec spec) {
int reg = spec.getNextReg();
if (reg > regCount) {
regCount = reg;
}
}
}
}