Insert moves after arguments
Bug: 79186787
Change-Id: I628b347a85a42cfd681054c454b08b8bcd014c5c
diff --git a/src/main/java/com/android/tools/r8/ir/code/BasicBlock.java b/src/main/java/com/android/tools/r8/ir/code/BasicBlock.java
index fb75931..d59df07 100644
--- a/src/main/java/com/android/tools/r8/ir/code/BasicBlock.java
+++ b/src/main/java/com/android/tools/r8/ir/code/BasicBlock.java
@@ -48,10 +48,7 @@
assert instruction.getBlock() == this;
assert !instruction.isArgument() || argumentsAllowed;
assert !instruction.isDebugLocalRead() || !instruction.getDebugValues().isEmpty();
- // TODO(b/79186787): Ensure DEX backend inserts Move *after* arguments.
- if (!(instruction.isArgument()
- || instruction.isMove()
- || instruction.isDebugLocalsChange())) {
+ if (!instruction.isArgument()) {
argumentsAllowed = false;
}
}
diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
index 769c281..de85da5 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
@@ -125,7 +125,9 @@
// Mapping from basic blocks to the set of values live at entry to that basic block.
private Map<BasicBlock, Set<Value>> liveAtEntrySets;
// The value of the first argument, or null if the method has no arguments.
- private Value firstArgumentValue;
+ protected Value firstArgumentValue;
+ // The value of the last argument, or null if the method has no arguments.
+ private Value lastArgumentValue;
// The set of registers that are free for allocation.
private TreeSet<Integer> freeRegisters = new TreeSet<>();
@@ -2511,7 +2513,8 @@
Invoke invoke, PriorityQueue<Move> insertAtDefinition, InstructionListIterator insertAt) {
Move move = insertAtDefinition.poll();
// Rewind instruction iterator to the position where the first move needs to be inserted.
- Instruction previousDefinition = move.src().definition;
+ Instruction previousDefinition =
+ move.src().isArgument() ? lastArgumentValue.definition : move.src().definition;
while (insertAt.peekPrevious() != previousDefinition) {
insertAt.previous();
}
@@ -2519,7 +2522,8 @@
insertAt.add(move);
while (!insertAtDefinition.isEmpty()) {
move = insertAtDefinition.poll();
- Instruction currentDefinition = move.src().definition;
+ Instruction currentDefinition =
+ move.src().isArgument() ? lastArgumentValue.definition : move.src().definition;
assert currentDefinition.getNumber() >= previousDefinition.getNumber();
if (currentDefinition.getNumber() > previousDefinition.getNumber()) {
// Move the instruction iterator forward to where this move needs to be inserted.
@@ -2572,6 +2576,7 @@
last.getLiveIntervals().link(next.getLiveIntervals());
last = next;
}
+ lastArgumentValue = last;
}
}
diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/SpillMoveSet.java b/src/main/java/com/android/tools/r8/ir/regalloc/SpillMoveSet.java
index 3401b17..1ea788d 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/SpillMoveSet.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/SpillMoveSet.java
@@ -10,6 +10,7 @@
import com.android.tools.r8.ir.code.Instruction;
import com.android.tools.r8.ir.code.InstructionListIterator;
import com.android.tools.r8.ir.code.Position;
+import com.android.tools.r8.ir.code.Value;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
@@ -119,17 +120,33 @@
*/
public int scheduleAndInsertMoves(int tempRegister) {
for (BasicBlock block : code.blocks) {
- InstructionListIterator it = block.listIterator();
- while (it.hasNext()) {
- Instruction instruction = it.next();
+ InstructionListIterator insertAt = block.listIterator();
+ if (block == code.blocks.getFirst()) {
+ // Move insertAt iterator to the first non-argument, such that moves for the arguments will
+ // be inserted after the last argument.
+ while (insertAt.hasNext() && insertAt.peekNext().isArgument()) {
+ insertAt.next();
+ }
+ // Generate moves for each argument.
+ for (Value argumentValue = allocator.firstArgumentValue;
+ argumentValue != null;
+ argumentValue = argumentValue.getNextConsecutive()) {
+ Instruction instruction = argumentValue.definition;
+ int number = instruction.getNumber();
+ if (needsMovesBeforeInstruction(number)) {
+ scheduleMovesBeforeInstruction(tempRegister, instruction, insertAt);
+ }
+ }
+ }
+
+ while (insertAt.hasNext()) {
+ Instruction instruction = insertAt.peekNext();
+ assert !instruction.isArgument();
int number = instruction.getNumber();
if (needsMovesBeforeInstruction(number)) {
- // Move back so moves are inserted before the instruction.
- it.previous();
- scheduleMovesBeforeInstruction(tempRegister, number, it);
- // Move past the instruction again.
- it.next();
+ scheduleMovesBeforeInstruction(tempRegister, instruction, insertAt);
}
+ insertAt.next();
}
}
return usedTempRegisters;
@@ -218,14 +235,15 @@
}
private void scheduleMovesBeforeInstruction(
- int tempRegister, int instruction, InstructionListIterator insertAt) {
+ int tempRegister, Instruction instruction, InstructionListIterator insertAt) {
+ int number = instruction.getNumber();
Position position;
if (insertAt.hasPrevious() && insertAt.peekPrevious().isMoveException()) {
position = insertAt.peekPrevious().getPosition();
} else {
Instruction next = insertAt.peekNext();
- assert next.getNumber() == instruction;
+ assert next.getNumber() == number || instruction.isArgument();
position = next.getPosition();
if (position.isNone() && next.isGoto()) {
position = next.asGoto().getTarget().getPosition();
@@ -234,17 +252,17 @@
// Spill and restore moves for the incoming edge.
Set<SpillMove> inMoves =
- instructionToInMoves.computeIfAbsent(instruction - 1, (k) -> new LinkedHashSet<>());
+ instructionToInMoves.computeIfAbsent(number - 1, (k) -> new LinkedHashSet<>());
removeArgumentRestores(inMoves);
// Spill and restore moves for the outgoing edge.
Set<SpillMove> outMoves =
- instructionToOutMoves.computeIfAbsent(instruction - 1, (k) -> new LinkedHashSet<>());
+ instructionToOutMoves.computeIfAbsent(number - 1, (k) -> new LinkedHashSet<>());
removeArgumentRestores(outMoves);
// Get the phi moves for this instruction and schedule them with the out going spill moves.
Set<SpillMove> phiMoves =
- instructionToPhiMoves.computeIfAbsent(instruction - 1, (k) -> new LinkedHashSet<>());
+ instructionToPhiMoves.computeIfAbsent(number - 1, (k) -> new LinkedHashSet<>());
// Remove/rewrite moves that we can guarantee will not be needed.
pruneParallelMoveSets(inMoves, outMoves, phiMoves);
