Merge "Combine the removal of unneeded catch handlers with dead code removal"
diff --git a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
index f58ea72..9d8cbcf 100644
--- a/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
+++ b/src/main/java/com/android/tools/r8/ir/conversion/IRConverter.java
@@ -453,7 +453,6 @@
Log.debug(getClass(), "Intermediate (SSA) flow graph for %s:\n%s",
method.toSourceString(), code);
}
- codeRewriter.removeUnneededCatchHandlers(code);
// Dead code removal. Performed after simplifications to remove code that becomes dead
// as a result of those simplifications. The following optimizations could reveal more
// dead code which is removed right before register allocation in performRegisterAllocation.
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java b/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
index c280a23..f26cacd 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/CodeRewriter.java
@@ -1149,25 +1149,6 @@
assert code.isConsistentSSA();
}
- public void removeUnneededCatchHandlers(IRCode code) {
- DominatorTree dominator = new DominatorTree(code);
- code.clearMarks();
- for (BasicBlock block : code.blocks) {
- if (block.hasCatchHandlers() && !block.canThrow()) {
- CatchHandlers<BasicBlock> handlers = block.getCatchHandlers();
- for (BasicBlock target : handlers.getUniqueTargets()) {
- for (BasicBlock unlinked : block.unlink(target, dominator)) {
- if (!unlinked.isMarked()) {
- unlinked.mark();
- }
- }
- }
- }
- }
- code.removeMarkedBlocks();
- assert code.isConsistentSSA();
- }
-
public void rewriteLongCompareAndRequireNonNull(IRCode code, boolean canUseObjectsNonNull) {
InstructionIterator iterator = code.instructionIterator();
@@ -1204,7 +1185,6 @@
// Note that addSuppressed() and getSuppressed() methods are final in
// Throwable, so these changes don't have to worry about overrides.
public void rewriteThrowableAddAndGetSuppressed(IRCode code) {
- boolean removeUnneededCatchHandlers = false;
DexItemFactory.ThrowableMethods throwableMethods = dexItemFactory.throwableMethods;
for (BasicBlock block : code.blocks) {
@@ -1217,15 +1197,12 @@
if (matchesMethodOfThrowable(invokedMethod, throwableMethods.addSuppressed)) {
// Remove Throwable::addSuppressed(Throwable) call.
iterator.remove();
- removeUnneededCatchHandlers = true;
-
} else if (matchesMethodOfThrowable(invokedMethod, throwableMethods.getSuppressed)) {
Value destValue = current.outValue();
if (destValue == null) {
// If the result of the call was not used we don't create
// an empty array and just remove the call.
iterator.remove();
- removeUnneededCatchHandlers = true;
continue;
}
@@ -1243,21 +1220,10 @@
NewArrayEmpty newArray = new NewArrayEmpty(destValue, zero,
dexItemFactory.createType(dexItemFactory.throwableArrayDescriptor));
iterator.replaceCurrentInstruction(newArray);
-
- // NOTE: nothing needs to be changed in catch handlers since we replace
- // one throwable instruction with another.
}
}
}
}
-
- // If at least one addSuppressed(...) call was removed, or we were able
- // to remove getSuppressed() call without replacing it with a new empty array,
- // we need to deal with possible unreachable catch handlers.
- if (removeUnneededCatchHandlers) {
- removeUnneededCatchHandlers(code);
- }
-
assert code.isConsistentSSA();
}
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/DeadCodeRemover.java b/src/main/java/com/android/tools/r8/ir/optimize/DeadCodeRemover.java
index d6023ed..0c60642 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/DeadCodeRemover.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/DeadCodeRemover.java
@@ -4,6 +4,8 @@
package com.android.tools.r8.ir.optimize;
import com.android.tools.r8.ir.code.BasicBlock;
+import com.android.tools.r8.ir.code.CatchHandlers;
+import com.android.tools.r8.ir.code.DominatorTree;
import com.android.tools.r8.ir.code.IRCode;
import com.android.tools.r8.ir.code.Instruction;
import com.android.tools.r8.ir.code.InstructionListIterator;
@@ -11,6 +13,7 @@
import com.android.tools.r8.ir.code.Value;
import com.android.tools.r8.utils.InternalOptions;
import java.util.ArrayList;
+import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
@@ -20,14 +23,48 @@
public static void removeDeadCode(
IRCode code, CodeRewriter codeRewriter, InternalOptions options) {
Queue<BasicBlock> worklist = new LinkedList<>();
+ DominatorTree dominator = new DominatorTree(code);
+ code.clearMarks();
worklist.addAll(code.blocks);
for (BasicBlock block = worklist.poll(); block != null; block = worklist.poll()) {
+ if (block.isMarked()) {
+ // Ignore marked blocks, as they are scheduled for removal.
+ continue;
+ }
removeDeadInstructions(worklist, block, options);
removeDeadPhis(worklist, block, options);
+ removeUnneededCatchHandlers(worklist, block, dominator);
}
+ code.removeMarkedBlocks();
+ assert code.isConsistentSSA();
codeRewriter.rewriteMoveResult(code);
}
+ // Add the block from where the value originates to the worklist.
+ private static void updateWorklist(Queue<BasicBlock> worklist, Value value) {
+ BasicBlock block;
+ if (value.isPhi()) {
+ block = value.asPhi().getBlock();
+ } else {
+ block = value.definition.getBlock();
+ }
+ if (!block.isMarked()) {
+ worklist.add(block);
+ }
+ }
+
+ // Add all blocks from where the in-values to the instruction originates.
+ private static void updateWorklist(Queue<BasicBlock> worklist, Instruction instruction) {
+ for (Value inValue : instruction.inValues()) {
+ updateWorklist(worklist, inValue);
+ }
+
+ Value previousLocalValue = instruction.getPreviousLocalValue();
+ if (previousLocalValue != null) {
+ updateWorklist(worklist, previousLocalValue);
+ }
+ }
+
private static void removeDeadPhis(
Queue<BasicBlock> worklist, BasicBlock block, InternalOptions options) {
List<Phi> toRemove = new ArrayList<>();
@@ -36,11 +73,7 @@
toRemove.add(phi);
for (Value operand : phi.getOperands()) {
operand.removePhiUser(phi);
- if (operand.isPhi()) {
- worklist.add(operand.asPhi().getBlock());
- } else {
- worklist.add(operand.definition.getBlock());
- }
+ updateWorklist(worklist, operand);
}
}
}
@@ -83,26 +116,31 @@
assert outValue != null;
if (!outValue.isDead(options)) {
continue;
+
}
- for (Value inValue : current.inValues()) {
- if (inValue.isPhi()) {
- worklist.add(inValue.asPhi().getBlock());
- } else {
- worklist.add(inValue.definition.getBlock());
- }
- }
- Value previousLocalValue = current.getPreviousLocalValue();
- if (previousLocalValue != null) {
- if (previousLocalValue.isPhi()) {
- worklist.add(previousLocalValue.asPhi().getBlock());
- } else {
- worklist.add(previousLocalValue.definition.getBlock());
- }
- }
+ updateWorklist(worklist, current);
// All users will be removed for this instruction. Eagerly clear them so further inspection
// of this instruction during dead code elimination will terminate here.
outValue.clearUsers();
iterator.remove();
}
}
+
+ private static void removeUnneededCatchHandlers(
+ Queue<BasicBlock> worklist, BasicBlock block, DominatorTree dominator) {
+ if (block.hasCatchHandlers() && !block.canThrow()) {
+ CatchHandlers<BasicBlock> handlers = block.getCatchHandlers();
+ for (BasicBlock target : handlers.getUniqueTargets()) {
+ for (BasicBlock unlinked : block.unlink(target, dominator)) {
+ if (!unlinked.isMarked()) {
+ Iterator<Instruction> iterator = unlinked.iterator();
+ while (iterator.hasNext()) {
+ updateWorklist(worklist, iterator.next());
+ }
+ unlinked.mark();
+ }
+ }
+ }
+ }
+ }
}
