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/*
* 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 org.snapscript.dx.dex.code;
import java.util.ArrayList;
import org.snapscript.dx.dex.DexOptions;
import org.snapscript.dx.io.Opcodes;
import org.snapscript.dx.rop.code.BasicBlock;
import org.snapscript.dx.rop.code.BasicBlockList;
import org.snapscript.dx.rop.code.FillArrayDataInsn;
import org.snapscript.dx.rop.code.Insn;
import org.snapscript.dx.rop.code.LocalVariableInfo;
import org.snapscript.dx.rop.code.PlainCstInsn;
import org.snapscript.dx.rop.code.PlainInsn;
import org.snapscript.dx.rop.code.RegOps;
import org.snapscript.dx.rop.code.RegisterSpec;
import org.snapscript.dx.rop.code.RegisterSpecList;
import org.snapscript.dx.rop.code.RegisterSpecSet;
import org.snapscript.dx.rop.code.Rop;
import org.snapscript.dx.rop.code.RopMethod;
import org.snapscript.dx.rop.code.SourcePosition;
import org.snapscript.dx.rop.code.SwitchInsn;
import org.snapscript.dx.rop.code.ThrowingCstInsn;
import org.snapscript.dx.rop.code.ThrowingInsn;
import org.snapscript.dx.rop.cst.Constant;
import org.snapscript.dx.rop.cst.CstInteger;
import org.snapscript.dx.util.Bits;
import org.snapscript.dx.util.IntList;
/**
* Translator from {@link RopMethod} to {@link DalvCode}. The {@link
* #translate} method is the thing to call on this class.
*/
public final class RopTranslator {
/** {@code non-null;} options for dex output */
private final DexOptions dexOptions;
/** {@code non-null;} method to translate */
private final RopMethod method;
/**
* how much position info to preserve; one of the static
* constants in {@link PositionList}
*/
private final int positionInfo;
/** {@code null-ok;} local variable info to use */
private final LocalVariableInfo locals;
/** {@code non-null;} container for all the address objects for the method */
private final BlockAddresses addresses;
/** {@code non-null;} list of output instructions in-progress */
private final OutputCollector output;
/** {@code non-null;} visitor to use during translation */
private final TranslationVisitor translationVisitor;
/** {@code >= 0;} register count for the method */
private final int regCount;
/** {@code null-ok;} block output order; becomes non-null in {@link #pickOrder} */
private int[] order;
/** size, in register units, of all the parameters to this method */
private final int paramSize;
/**
* true if the parameters to this method happen to be in proper order
* at the end of the frame (as the optimizer emits them)
*/
private boolean paramsAreInOrder;
/**
* Translates a {@link RopMethod}. This may modify the given
* input.
*
* @param method {@code non-null;} the original method
* @param positionInfo how much position info to preserve; one of the
* static constants in {@link PositionList}
* @param locals {@code null-ok;} local variable information to use
* @param paramSize size, in register units, of all the parameters to
* this method
* @param dexOptions {@code non-null;} options for dex output
* @return {@code non-null;} the translated version
*/
public static DalvCode translate(RopMethod method, int positionInfo,
LocalVariableInfo locals, int paramSize, DexOptions dexOptions) {
RopTranslator translator =
new RopTranslator(method, positionInfo, locals, paramSize, dexOptions);
return translator.translateAndGetResult();
}
/**
* Constructs an instance. This method is private. Use {@link #translate}.
*
* @param method {@code non-null;} the original method
* @param positionInfo how much position info to preserve; one of the
* static constants in {@link PositionList}
* @param locals {@code null-ok;} local variable information to use
* @param paramSize size, in register units, of all the parameters to
* this method
* @param dexOptions {@code non-null;} options for dex output
*/
private RopTranslator(RopMethod method, int positionInfo, LocalVariableInfo locals,
int paramSize, DexOptions dexOptions) {
this.dexOptions = dexOptions;
this.method = method;
this.positionInfo = positionInfo;
this.locals = locals;
this.addresses = new BlockAddresses(method);
this.paramSize = paramSize;
this.order = null;
this.paramsAreInOrder = calculateParamsAreInOrder(method, paramSize);
BasicBlockList blocks = method.getBlocks();
int bsz = blocks.size();
/*
* Max possible instructions includes three code address
* objects per basic block (to the first and last instruction,
* and just past the end of the block), and the possibility of
* an extra goto at the end of each basic block.
*/
int maxInsns = (bsz * 3) + blocks.getInstructionCount();
if (locals != null) {
/*
* If we're tracking locals, then there's could be another
* extra instruction per block (for the locals state at the
* start of the block) as well as one for each interblock
* local introduction.
*/
maxInsns += bsz + locals.getAssignmentCount();
}
/*
* If params are not in order, we will need register space
* for them before this is all over...
*/
this.regCount = blocks.getRegCount()
+ (paramsAreInOrder ? 0 : this.paramSize);
this.output = new OutputCollector(dexOptions, maxInsns, bsz * 3, regCount);
if (locals != null) {
this.translationVisitor =
new LocalVariableAwareTranslationVisitor(output, locals);
} else {
this.translationVisitor = new TranslationVisitor(output);
}
}
/**
* Checks to see if the move-param instructions that occur in this
* method happen to slot the params in an order at the top of the
* stack frame that matches dalvik's calling conventions. This will
* alway result in "true" for methods that have run through the
* SSA optimizer.
*
* @param paramSize size, in register units, of all the parameters
* to this method
*/
private static boolean calculateParamsAreInOrder(RopMethod method,
final int paramSize) {
final boolean[] paramsAreInOrder = { true };
final int initialRegCount = method.getBlocks().getRegCount();
/*
* We almost could just check the first block here, but the
* {@code cf} layer will put in a second move-param in a
* subsequent block in the case of synchronized methods.
*/
method.getBlocks().forEachInsn(new Insn.BaseVisitor() {
@Override
public void visitPlainCstInsn(PlainCstInsn insn) {
if (insn.getOpcode().getOpcode()== RegOps.MOVE_PARAM) {
int param =
((CstInteger) insn.getConstant()).getValue();
paramsAreInOrder[0] = paramsAreInOrder[0]
&& ((initialRegCount - paramSize + param)
== insn.getResult().getReg());
}
}
});
return paramsAreInOrder[0];
}
/**
* Does the translation and returns the result.
*
* @return {@code non-null;} the result
*/
private DalvCode translateAndGetResult() {
pickOrder();
outputInstructions();
StdCatchBuilder catches =
new StdCatchBuilder(method, order, addresses);
return new DalvCode(positionInfo, output.getFinisher(), catches);
}
/**
* Performs initial creation of output instructions based on the
* original blocks.
*/
private void outputInstructions() {
BasicBlockList blocks = method.getBlocks();
int[] order = this.order;
int len = order.length;
// Process the blocks in output order.
for (int i = 0; i < len; i++) {
int nextI = i + 1;
int nextLabel = (nextI == order.length) ? -1 : order[nextI];
outputBlock(blocks.labelToBlock(order[i]), nextLabel);
}
}
/**
* Helper for {@link #outputInstructions}, which does the processing
* and output of one block.
*
* @param block {@code non-null;} the block to process and output
* @param nextLabel {@code >= -1;} the next block that will be processed, or
* {@code -1} if there is no next block
*/
private void outputBlock(BasicBlock block, int nextLabel) {
// Append the code address for this block.
CodeAddress startAddress = addresses.getStart(block);
output.add(startAddress);
// Append the local variable state for the block.
if (locals != null) {
RegisterSpecSet starts = locals.getStarts(block);
output.add(new LocalSnapshot(startAddress.getPosition(),
starts));
}
/*
* Choose and append an output instruction for each original
* instruction.
*/
translationVisitor.setBlock(block, addresses.getLast(block));
block.getInsns().forEach(translationVisitor);
// Insert the block end code address.
output.add(addresses.getEnd(block));
// Set up for end-of-block activities.
int succ = block.getPrimarySuccessor();
Insn lastInsn = block.getLastInsn();
/*
* Check for (and possibly correct for) a non-optimal choice of
* which block will get output next.
*/
if ((succ >= 0) && (succ != nextLabel)) {
/*
* The block has a "primary successor" and that primary
* successor isn't the next block to be output.
*/
Rop lastRop = lastInsn.getOpcode();
if ((lastRop.getBranchingness() == Rop.BRANCH_IF) &&
(block.getSecondarySuccessor() == nextLabel)) {
/*
* The block ends with an "if" of some sort, and its
* secondary successor (the "then") is in fact the
* next block to output. So, reverse the sense of
* the test, so that we can just emit the next block
* without an interstitial goto.
*/
output.reverseBranch(1, addresses.getStart(succ));
} else {
/*
* Our only recourse is to add a goto here to get the
* flow to be correct.
*/
TargetInsn insn =
new TargetInsn(Dops.GOTO, lastInsn.getPosition(),
RegisterSpecList.EMPTY,
addresses.getStart(succ));
output.add(insn);
}
}
}
/**
* Picks an order for the blocks by doing "trace" analysis.
*/
private void pickOrder() {
BasicBlockList blocks = method.getBlocks();
int sz = blocks.size();
int maxLabel = blocks.getMaxLabel();
int[] workSet = Bits.makeBitSet(maxLabel);
int[] tracebackSet = Bits.makeBitSet(maxLabel);
for (int i = 0; i < sz; i++) {
BasicBlock one = blocks.get(i);
Bits.set(workSet, one.getLabel());
}
int[] order = new int[sz];
int at = 0;
/*
* Starting with the designated "first label" (that is, the
* first block of the method), add that label to the order,
* and then pick its first as-yet unordered successor to
* immediately follow it, giving top priority to the primary
* (aka default) successor (if any). Keep following successors
* until the trace runs out of possibilities. Then, continue
* by finding an unordered chain containing the first as-yet
* unordered block, and adding it to the order, and so on.
*/
for (int label = method.getFirstLabel();
label != -1;
label = Bits.findFirst(workSet, 0)) {
/*
* Attempt to trace backward from the chosen block to an
* as-yet unordered predecessor which lists the chosen
* block as its primary successor, and so on, until we
* fail to find such an unordered predecessor. Start the
* trace with that block. Note that the first block in the
* method has no predecessors, so in that case this loop
* will simply terminate with zero iterations and without
* picking a new starter block.
*/
traceBack:
for (;;) {
IntList preds = method.labelToPredecessors(label);
int psz = preds.size();
for (int i = 0; i < psz; i++) {
int predLabel = preds.get(i);
if (Bits.get(tracebackSet, predLabel)) {
/*
* We found a predecessor loop; stop tracing back
* from here.
*/
break;
}
if (!Bits.get(workSet, predLabel)) {
// This one's already ordered.
continue;
}
BasicBlock pred = blocks.labelToBlock(predLabel);
if (pred.getPrimarySuccessor() == label) {
// Found one!
label = predLabel;
Bits.set(tracebackSet, label);
continue traceBack;
}
}
// Failed to find a better block to start the trace.
break;
}
/*
* Trace a path from the chosen block to one of its
* unordered successors (hopefully the primary), and so
* on, until we run out of unordered successors.
*/
while (label != -1) {
Bits.clear(workSet, label);
Bits.clear(tracebackSet, label);
order[at] = label;
at++;
BasicBlock one = blocks.labelToBlock(label);
BasicBlock preferredBlock = blocks.preferredSuccessorOf(one);
if (preferredBlock == null) {
break;
}
int preferred = preferredBlock.getLabel();
int primary = one.getPrimarySuccessor();
if (Bits.get(workSet, preferred)) {
/*
* Order the current block's preferred successor
* next, as it has yet to be scheduled.
*/
label = preferred;
} else if ((primary != preferred) && (primary >= 0)
&& Bits.get(workSet, primary)) {
/*
* The primary is available, so use that.
*/
label = primary;
} else {
/*
* There's no obvious candidate, so pick the first
* one that's available, if any.
*/
IntList successors = one.getSuccessors();
int ssz = successors.size();
label = -1;
for (int i = 0; i < ssz; i++) {
int candidate = successors.get(i);
if (Bits.get(workSet, candidate)) {
label = candidate;
break;
}
}
}
}
}
if (at != sz) {
// There was a duplicate block label.
throw new RuntimeException("shouldn't happen");
}
this.order = order;
}
/**
* Gets the complete register list (result and sources) out of a
* given rop instruction. For insns that are commutative, have
* two register sources, and have a source equal to the result,
* place that source first.
*
* @param insn {@code non-null;} instruction in question
* @return {@code non-null;} the instruction's complete register list
*/
private static RegisterSpecList getRegs(Insn insn) {
return getRegs(insn, insn.getResult());
}
/**
* Gets the complete register list (result and sources) out of a
* given rop instruction. For insns that are commutative, have
* two register sources, and have a source equal to the result,
* place that source first.
*
* @param insn {@code non-null;} instruction in question
* @param resultReg {@code null-ok;} the real result to use (ignore the insn's)
* @return {@code non-null;} the instruction's complete register list
*/
private static RegisterSpecList getRegs(Insn insn,
RegisterSpec resultReg) {
RegisterSpecList regs = insn.getSources();
if (insn.getOpcode().isCommutative()
&& (regs.size() == 2)
&& (resultReg.getReg() == regs.get(1).getReg())) {
/*
* For commutative ops which have two register sources,
* if the second source is the same register as the result,
* swap the sources so that an opcode of form 12x can be selected
* instead of one of form 23x
*/
regs = RegisterSpecList.make(regs.get(1), regs.get(0));
}
if (resultReg == null) {
return regs;
}
return regs.withFirst(resultReg);
}
/**
* Instruction visitor class for doing the instruction translation per se.
*/
private class TranslationVisitor implements Insn.Visitor {
/** {@code non-null;} list of output instructions in-progress */
private final OutputCollector output;
/** {@code non-null;} basic block being worked on */
private BasicBlock block;
/**
* {@code null-ok;} code address for the salient last instruction of the
* block (used before switches and throwing instructions)
*/
private CodeAddress lastAddress;
/**
* Constructs an instance.
*
* @param output {@code non-null;} destination for instruction output
*/
public TranslationVisitor(OutputCollector output) {
this.output = output;
}
/**
* Sets the block currently being worked on.
*
* @param block {@code non-null;} the block
* @param lastAddress {@code non-null;} code address for the salient
* last instruction of the block
*/
public void setBlock(BasicBlock block, CodeAddress lastAddress) {
this.block = block;
this.lastAddress = lastAddress;
}
/** {@inheritDoc} */
public void visitPlainInsn(PlainInsn insn) {
Rop rop = insn.getOpcode();
if (rop.getOpcode() == RegOps.MARK_LOCAL) {
/*
* Ignore these. They're dealt with by
* the LocalVariableAwareTranslationVisitor
*/
return;
}
if (rop.getOpcode() == RegOps.MOVE_RESULT_PSEUDO) {
// These get skipped
return;
}
SourcePosition pos = insn.getPosition();
Dop opcode = RopToDop.dopFor(insn);
DalvInsn di;
switch (rop.getBranchingness()) {
case Rop.BRANCH_NONE:
case Rop.BRANCH_RETURN:
case Rop.BRANCH_THROW: {
di = new SimpleInsn(opcode, pos, getRegs(insn));
break;
}
case Rop.BRANCH_GOTO: {
/*
* Code in the main translation loop will emit a
* goto if necessary (if the branch isn't to the
* immediately subsequent block).
*/
return;
}
case Rop.BRANCH_IF: {
int target = block.getSuccessors().get(1);
di = new TargetInsn(opcode, pos, getRegs(insn),
addresses.getStart(target));
break;
}
default: {
throw new RuntimeException("shouldn't happen");
}
}
addOutput(di);
}
/** {@inheritDoc} */
public void visitPlainCstInsn(PlainCstInsn insn) {
SourcePosition pos = insn.getPosition();
Dop opcode = RopToDop.dopFor(insn);
Rop rop = insn.getOpcode();
int ropOpcode = rop.getOpcode();
DalvInsn di;
if (rop.getBranchingness() != Rop.BRANCH_NONE) {
throw new RuntimeException("shouldn't happen");
}
if (ropOpcode == RegOps.MOVE_PARAM) {
if (!paramsAreInOrder) {
/*
* Parameters are not in order at the top of the reg space.
* We need to add moves.
*/
RegisterSpec dest = insn.getResult();
int param =
((CstInteger) insn.getConstant()).getValue();
RegisterSpec source =
RegisterSpec.make(regCount - paramSize + param,
dest.getType());
di = new SimpleInsn(opcode, pos,
RegisterSpecList.make(dest, source));
addOutput(di);
}
} else {
// No moves required for the parameters
RegisterSpecList regs = getRegs(insn);
di = new CstInsn(opcode, pos, regs, insn.getConstant());
addOutput(di);
}
}
/** {@inheritDoc} */
public void visitSwitchInsn(SwitchInsn insn) {
SourcePosition pos = insn.getPosition();
IntList cases = insn.getCases();
IntList successors = block.getSuccessors();
int casesSz = cases.size();
int succSz = successors.size();
int primarySuccessor = block.getPrimarySuccessor();
/*
* Check the assumptions that the number of cases is one
* less than the number of successors and that the last
* successor in the list is the primary (in this case, the
* default). This test is here to guard against forgetting
* to change this code if the way switch instructions are
* constructed also gets changed.
*/
if ((casesSz != (succSz - 1)) ||
(primarySuccessor != successors.get(casesSz))) {
throw new RuntimeException("shouldn't happen");
}
CodeAddress[] switchTargets = new CodeAddress[casesSz];
for (int i = 0; i < casesSz; i++) {
int label = successors.get(i);
switchTargets[i] = addresses.getStart(label);
}
CodeAddress dataAddress = new CodeAddress(pos);
SwitchData dataInsn =
new SwitchData(pos, lastAddress, cases, switchTargets);
Dop opcode = dataInsn.isPacked() ?
Dops.PACKED_SWITCH : Dops.SPARSE_SWITCH;
TargetInsn switchInsn =
new TargetInsn(opcode, pos, getRegs(insn), dataAddress);
addOutput(lastAddress);
addOutput(switchInsn);
addOutputSuffix(new OddSpacer(pos));
addOutputSuffix(dataAddress);
addOutputSuffix(dataInsn);
}
/**
* Looks forward to the current block's primary successor, returning
* the RegisterSpec of the result of the move-result-pseudo at the
* top of that block or null if none.
*
* @return {@code null-ok;} result of move-result-pseudo at the beginning of
* primary successor
*/
private RegisterSpec getNextMoveResultPseudo()
{
int label = block.getPrimarySuccessor();
if (label < 0) {
return null;
}
Insn insn
= method.getBlocks().labelToBlock(label).getInsns().get(0);
if (insn.getOpcode().getOpcode() != RegOps.MOVE_RESULT_PSEUDO) {
return null;
} else {
return insn.getResult();
}
}
/** {@inheritDoc} */
public void visitThrowingCstInsn(ThrowingCstInsn insn) {
SourcePosition pos = insn.getPosition();
Dop opcode = RopToDop.dopFor(insn);
Rop rop = insn.getOpcode();
Constant cst = insn.getConstant();
if (rop.getBranchingness() != Rop.BRANCH_THROW) {
throw new RuntimeException("shouldn't happen");
}
addOutput(lastAddress);
if (rop.isCallLike()) {
RegisterSpecList regs = insn.getSources();
DalvInsn di = new CstInsn(opcode, pos, regs, cst);
addOutput(di);
} else {
RegisterSpec realResult = getNextMoveResultPseudo();
RegisterSpecList regs = getRegs(insn, realResult);
DalvInsn di;
boolean hasResult = opcode.hasResult()
|| (rop.getOpcode() == RegOps.CHECK_CAST);
if (hasResult != (realResult != null)) {
throw new RuntimeException(
"Insn with result/move-result-pseudo mismatch " +
insn);
}
if ((rop.getOpcode() == RegOps.NEW_ARRAY) &&
(opcode.getOpcode() != Opcodes.NEW_ARRAY)) {
/*
* It's a type-specific new-array-, and
* so it should be turned into a SimpleInsn (no
* constant ref as it's implicit).
*/
di = new SimpleInsn(opcode, pos, regs);
} else {
/*
* This is the general case for constant-bearing
* instructions.
*/
di = new CstInsn(opcode, pos, regs, cst);
}
addOutput(di);
}
}
/** {@inheritDoc} */
public void visitThrowingInsn(ThrowingInsn insn) {
SourcePosition pos = insn.getPosition();
Dop opcode = RopToDop.dopFor(insn);
Rop rop = insn.getOpcode();
RegisterSpec realResult;
if (rop.getBranchingness() != Rop.BRANCH_THROW) {
throw new RuntimeException("shouldn't happen");
}
realResult = getNextMoveResultPseudo();
if (opcode.hasResult() != (realResult != null)) {
throw new RuntimeException(
"Insn with result/move-result-pseudo mismatch" + insn);
}
addOutput(lastAddress);
DalvInsn di = new SimpleInsn(opcode, pos,
getRegs(insn, realResult));
addOutput(di);
}
/** {@inheritDoc} */
public void visitFillArrayDataInsn(FillArrayDataInsn insn) {
SourcePosition pos = insn.getPosition();
Constant cst = insn.getConstant();
ArrayList values = insn.getInitValues();
Rop rop = insn.getOpcode();
if (rop.getBranchingness() != Rop.BRANCH_NONE) {
throw new RuntimeException("shouldn't happen");
}
CodeAddress dataAddress = new CodeAddress(pos);
ArrayData dataInsn =
new ArrayData(pos, lastAddress, values, cst);
TargetInsn fillArrayDataInsn =
new TargetInsn(Dops.FILL_ARRAY_DATA, pos, getRegs(insn),
dataAddress);
addOutput(lastAddress);
addOutput(fillArrayDataInsn);
addOutputSuffix(new OddSpacer(pos));
addOutputSuffix(dataAddress);
addOutputSuffix(dataInsn);
}
/**
* Adds to the output.
*
* @param insn {@code non-null;} instruction to add
*/
protected void addOutput(DalvInsn insn) {
output.add(insn);
}
/**
* Adds to the output suffix.
*
* @param insn {@code non-null;} instruction to add
*/
protected void addOutputSuffix(DalvInsn insn) {
output.addSuffix(insn);
}
}
/**
* Instruction visitor class for doing instruction translation with
* local variable tracking
*/
private class LocalVariableAwareTranslationVisitor
extends TranslationVisitor {
/** {@code non-null;} local variable info */
private LocalVariableInfo locals;
/**
* Constructs an instance.
*
* @param output {@code non-null;} destination for instruction output
* @param locals {@code non-null;} the local variable info
*/
public LocalVariableAwareTranslationVisitor(OutputCollector output,
LocalVariableInfo locals) {
super(output);
this.locals = locals;
}
/** {@inheritDoc} */
@Override
public void visitPlainInsn(PlainInsn insn) {
super.visitPlainInsn(insn);
addIntroductionIfNecessary(insn);
}
/** {@inheritDoc} */
@Override
public void visitPlainCstInsn(PlainCstInsn insn) {
super.visitPlainCstInsn(insn);
addIntroductionIfNecessary(insn);
}
/** {@inheritDoc} */
@Override
public void visitSwitchInsn(SwitchInsn insn) {
super.visitSwitchInsn(insn);
addIntroductionIfNecessary(insn);
}
/** {@inheritDoc} */
@Override
public void visitThrowingCstInsn(ThrowingCstInsn insn) {
super.visitThrowingCstInsn(insn);
addIntroductionIfNecessary(insn);
}
/** {@inheritDoc} */
@Override
public void visitThrowingInsn(ThrowingInsn insn) {
super.visitThrowingInsn(insn);
addIntroductionIfNecessary(insn);
}
/**
* Adds a {@link LocalStart} to the output if the given
* instruction in fact introduces a local variable.
*
* @param insn {@code non-null;} instruction in question
*/
public void addIntroductionIfNecessary(Insn insn) {
RegisterSpec spec = locals.getAssignment(insn);
if (spec != null) {
addOutput(new LocalStart(insn.getPosition(), spec));
}
}
}
}
