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fix: better code styling for if-else blocks (#1455)
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@skylot
skylot committed Apr 26, 2022
1 parent 3366bf3 commit a71b3a7
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Showing 17 changed files with 753 additions and 115 deletions.
1 change: 1 addition & 0 deletions jadx-core/src/main/java/jadx/core/dex/attributes/AFlag.java
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Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,7 @@ public enum AFlag {
RERUN_SSA_TRANSFORM,

METHOD_CANDIDATE_FOR_INLINE,
USE_LINES_HINTS, // source lines info in methods can be trusted

DISABLE_BLOCKS_LOCK,

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10 changes: 10 additions & 0 deletions jadx-core/src/main/java/jadx/core/dex/regions/conditions/IfCondition.java
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Original file line number Diff line number Diff line change
Expand Up @@ -278,6 +278,16 @@ public List<InsnNode> collectInsns() {
return list;
}

public int getSourceLine() {
for (InsnNode insn : collectInsns()) {
int line = insn.getSourceLine();
if (line != 0) {
return line;
}
}
return 0;
}

@Nullable
public InsnNode getFirstInsn() {
if (mode == Mode.COMPARE) {
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19 changes: 18 additions & 1 deletion jadx-core/src/main/java/jadx/core/dex/visitors/debuginfo/DebugInfoAttachVisitor.java
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Original file line number Diff line number Diff line change
@@ -1,12 +1,15 @@
package jadx.core.dex.visitors.debuginfo;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import jadx.api.plugins.input.data.IDebugInfo;
import jadx.api.plugins.input.data.ILocalVar;
import jadx.core.dex.attributes.AFlag;
import jadx.core.dex.attributes.nodes.LocalVarsDebugInfoAttr;
import jadx.core.dex.attributes.nodes.RegDebugInfoAttr;
import jadx.core.dex.instructions.InsnType;
import jadx.core.dex.instructions.args.ArgType;
import jadx.core.dex.instructions.args.InsnArg;
import jadx.core.dex.instructions.args.RegisterArg;
Expand All @@ -17,6 +20,7 @@
import jadx.core.dex.visitors.JadxVisitor;
import jadx.core.dex.visitors.blocks.BlockSplitter;
import jadx.core.dex.visitors.ssa.SSATransform;
import jadx.core.utils.ListUtils;
import jadx.core.utils.exceptions.JadxException;

@JadxVisitor(
Expand Down Expand Up @@ -52,17 +56,30 @@ private void attachSourceLines(MethodNode mth, Map<Integer, Integer> lineMapping
if (lineMapping.isEmpty()) {
return;
}
Map<Integer, Integer> linesStat = new HashMap<>(); // count repeating lines
for (Map.Entry<Integer, Integer> entry : lineMapping.entrySet()) {
try {
Integer offset = entry.getKey();
InsnNode insn = insnArr[offset];
if (insn != null) {
insn.setSourceLine(entry.getValue());
int line = entry.getValue();
insn.setSourceLine(line);
if (insn.getType() != InsnType.NOP) {
linesStat.merge(line, 1, (v, one) -> v + 1);
}
}
} catch (Exception e) {
mth.addWarnComment("Error attach source line", e);
}
}
// 3 here is allowed maximum for lines repeat,
// can occur in indexed 'for' loops (3 instructions with same line)
List<Map.Entry<Integer, Integer>> repeatingLines = ListUtils.filter(linesStat.entrySet(), p -> p.getValue() > 3);
if (repeatingLines.isEmpty()) {
mth.add(AFlag.USE_LINES_HINTS);
} else {
mth.addDebugComment("Don't trust debug lines info. Repeating lines: " + repeatingLines);
}
}

private void attachDebugInfo(MethodNode mth, List<ILocalVar> localVars, InsnNode[] insnArr) {
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122 changes: 71 additions & 51 deletions jadx-core/src/main/java/jadx/core/dex/visitors/regions/IfRegionVisitor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,47 +38,74 @@ private static class ProcessIfRegionVisitor extends AbstractRegionVisitor {
public boolean enterRegion(MethodNode mth, IRegion region) {
if (region instanceof IfRegion) {
IfRegion ifRegion = (IfRegion) region;
simplifyIfCondition(ifRegion);
moveReturnToThenBlock(mth, ifRegion);
moveBreakToThenBlock(ifRegion);
markElseIfChains(ifRegion);
orderBranches(mth, ifRegion);
markElseIfChains(mth, ifRegion);
}
return true;
}
}

private static class RemoveRedundantElseVisitor implements IRegionIterativeVisitor {
@Override
public boolean visitRegion(MethodNode mth, IRegion region) {
if (region instanceof IfRegion) {
return removeRedundantElseBlock(mth, (IfRegion) region);
@SuppressWarnings("UnnecessaryReturnStatement")
private static void orderBranches(MethodNode mth, IfRegion ifRegion) {
if (RegionUtils.isEmpty(ifRegion.getElseRegion())) {
return;
}
if (RegionUtils.isEmpty(ifRegion.getThenRegion())) {
invertIfRegion(ifRegion);
return;
}
if (mth.contains(AFlag.USE_LINES_HINTS)) {
int thenLine = RegionUtils.getFirstSourceLine(ifRegion.getThenRegion());
int elseLine = RegionUtils.getFirstSourceLine(ifRegion.getElseRegion());
if (thenLine != 0 && elseLine != 0) {
if (thenLine > elseLine) {
invertIfRegion(ifRegion);
}
return;
}
return false;
}
}

private static void simplifyIfCondition(IfRegion ifRegion) {
if (ifRegion.simplifyCondition()) {
IfCondition condition = ifRegion.getCondition();
if (condition.getMode() == Mode.NOT) {
if (condition != null && condition.getMode() == Mode.NOT) {
invertIfRegion(ifRegion);
}
}
IContainer elseRegion = ifRegion.getElseRegion();
if (elseRegion == null || RegionUtils.isEmpty(elseRegion)) {
int thenSize = insnsCount(ifRegion.getThenRegion());
int elseSize = insnsCount(ifRegion.getElseRegion());
if (isSimpleExitBlock(mth, ifRegion.getElseRegion())) {
if (isSimpleExitBlock(mth, ifRegion.getThenRegion())) {
if (elseSize < thenSize) {
invertIfRegion(ifRegion);
return;
}
}
boolean lastRegion = ifRegion == RegionUtils.getLastRegion(mth.getRegion());
if (elseSize == 1 && lastRegion && mth.isVoidReturn()) {
// single return at method end will be removed later
return;
}
if (!lastRegion) {
invertIfRegion(ifRegion);
}
return;
}
boolean thenIsEmpty = RegionUtils.isEmpty(ifRegion.getThenRegion());
if (thenIsEmpty || hasSimpleReturnBlock(ifRegion.getThenRegion())) {
boolean thenExit = RegionUtils.hasExitBlock(ifRegion.getThenRegion());
boolean elseExit = RegionUtils.hasExitBlock(ifRegion.getElseRegion());
if (elseExit && (!thenExit || elseSize < thenSize)) {
invertIfRegion(ifRegion);
return;
}

if (!thenIsEmpty) {
// move 'if' from then to make 'else if' chain
if (isIfRegion(ifRegion.getThenRegion())
&& !isIfRegion(elseRegion)) {
invertIfRegion(ifRegion);
}
// move 'if' from 'then' branch to make 'else if' chain
if (isIfRegion(ifRegion.getThenRegion())
&& !isIfRegion(ifRegion.getElseRegion())
&& !thenExit) {
invertIfRegion(ifRegion);
return;
}
// move 'break' into 'then' branch
if (RegionUtils.hasBreakInsn(ifRegion.getElseRegion())) {
invertIfRegion(ifRegion);
return;
}
}

Expand All @@ -88,33 +115,16 @@ private static boolean isIfRegion(IContainer container) {
}
if (container instanceof IRegion) {
List<IContainer> subBlocks = ((IRegion) container).getSubBlocks();
if (subBlocks.size() == 1 && subBlocks.get(0) instanceof IfRegion) {
return true;
}
return subBlocks.size() == 1 && subBlocks.get(0) instanceof IfRegion;
}
return false;
}

private static void moveReturnToThenBlock(MethodNode mth, IfRegion ifRegion) {
if (!mth.isVoidReturn()
&& hasSimpleReturnBlock(ifRegion.getElseRegion())
/* && insnsCount(ifRegion.getThenRegion()) < 2 */) {
invertIfRegion(ifRegion);
}
}

private static void moveBreakToThenBlock(IfRegion ifRegion) {
if (ifRegion.getElseRegion() != null
&& RegionUtils.hasBreakInsn(ifRegion.getElseRegion())) {
invertIfRegion(ifRegion);
}
}

/**
* Mark if-else-if chains
*/
private static void markElseIfChains(IfRegion ifRegion) {
if (hasSimpleReturnBlock(ifRegion.getThenRegion())) {
private static void markElseIfChains(MethodNode mth, IfRegion ifRegion) {
if (isSimpleExitBlock(mth, ifRegion.getThenRegion())) {
return;
}
IContainer elsRegion = ifRegion.getElseRegion();
Expand All @@ -127,6 +137,16 @@ private static void markElseIfChains(IfRegion ifRegion) {
}
}

private static class RemoveRedundantElseVisitor implements IRegionIterativeVisitor {
@Override
public boolean visitRegion(MethodNode mth, IRegion region) {
if (region instanceof IfRegion) {
return removeRedundantElseBlock(mth, (IfRegion) region);
}
return false;
}
}

private static boolean removeRedundantElseBlock(MethodNode mth, IfRegion ifRegion) {
if (ifRegion.getElseRegion() == null
|| ifRegion.contains(AFlag.ELSE_IF_CHAIN)
Expand Down Expand Up @@ -162,16 +182,16 @@ private static void invertIfRegion(IfRegion ifRegion) {
}
}

private static boolean hasSimpleReturnBlock(IContainer region) {
if (region == null) {
private static boolean isSimpleExitBlock(MethodNode mth, IContainer container) {
if (container == null) {
return false;
}
if (region.contains(AFlag.RETURN)) {
if (container.contains(AFlag.RETURN) || RegionUtils.isExitBlock(mth, container)) {
return true;
}
if (region instanceof IRegion) {
List<IContainer> subBlocks = ((IRegion) region).getSubBlocks();
return subBlocks.size() == 1 && subBlocks.get(0).contains(AFlag.RETURN);
if (container instanceof IRegion) {
List<IContainer> subBlocks = ((IRegion) container).getSubBlocks();
return subBlocks.size() == 1 && RegionUtils.isExitBlock(mth, subBlocks.get(0));
}
return false;
}
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5 changes: 4 additions & 1 deletion jadx-core/src/main/java/jadx/core/dex/visitors/regions/TernaryMod.java
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,8 @@ private static boolean makeTernaryInsn(MethodNode mth, IfRegion ifRegion) {
InsnNode thenInsn = tb.getInstructions().get(0);
InsnNode elseInsn = eb.getInstructions().get(0);

if (thenInsn.getSourceLine() != elseInsn.getSourceLine()) {
if (mth.contains(AFlag.USE_LINES_HINTS)
&& thenInsn.getSourceLine() != elseInsn.getSourceLine()) {
if (thenInsn.getSourceLine() != 0 && elseInsn.getSourceLine() != 0) {
// sometimes source lines incorrect
if (!checkLineStats(thenInsn, elseInsn)) {
Expand Down Expand Up @@ -134,6 +135,8 @@ private static boolean makeTernaryInsn(MethodNode mth, IfRegion ifRegion) {
InsnArg thenArg = InsnArg.wrapInsnIntoArg(thenInsn);
InsnArg elseArg = InsnArg.wrapInsnIntoArg(elseInsn);
TernaryInsn ternInsn = new TernaryInsn(ifRegion.getCondition(), resArg, thenArg, elseArg);
int branchLine = Math.max(thenInsn.getSourceLine(), elseInsn.getSourceLine());
ternInsn.setSourceLine(Math.max(ifRegion.getSourceLine(), branchLine));

InsnRemover.unbindResult(mth, elseInsn);

Expand Down
27 changes: 24 additions & 3 deletions jadx-core/src/main/java/jadx/core/utils/BlockUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,16 @@ public static InsnNode getLastInsnWithType(IBlock block, InsnType expectedType)
return null;
}

public static int getFirstSourceLine(IBlock block) {
for (InsnNode insn : block.getInstructions()) {
int line = insn.getSourceLine();
if (line != 0) {
return line;
}
}
return 0;
}

@Nullable
public static InsnNode getFirstInsn(@Nullable IBlock block) {
if (block == null) {
Expand All @@ -207,11 +217,22 @@ public static InsnNode getLastInsn(@Nullable IBlock block) {
}

public static boolean isExitBlock(MethodNode mth, BlockNode block) {
BlockNode exitBlock = mth.getExitBlock();
if (block == exitBlock) {
if (block == mth.getExitBlock()) {
return true;
}
return exitBlock.getPredecessors().contains(block);
return isExitBlock(block);
}

public static boolean isExitBlock(BlockNode block) {
List<BlockNode> successors = block.getSuccessors();
if (successors.isEmpty()) {
return true;
}
if (successors.size() == 1) {
BlockNode next = successors.get(0);
return next.getSuccessors().isEmpty();
}
return false;
}

public static boolean containsExitInsn(IBlock block) {
Expand Down
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