@Override protected void handleSpillSlot(Interval interval) { assert interval.location() != null : "interval not assigned " + interval; if (interval.canMaterialize()) { assert !isStackSlot(interval.location()) : "interval can materialize but assigned to a stack slot " + interval; return; } assert isStackSlot(interval.location()) : "interval not assigned to a stack slot " + interval; try (Scope s1 = Debug.scope("LSRAOptimization")) { Debug.log("adding stack to unhandled list %s", interval); unhandledLists.addToListSortedByStartAndUsePositions(RegisterBinding.Stack, interval); } }
private void splitRegisterInterval(Interval interval, Register reg) { // collect current usage of registers initVarsForAlloc(interval); initUseLists(false); spillExcludeActiveFixed(); // spillBlockUnhandledFixed(cur); assert unhandledLists.get(RegisterBinding.Fixed) == Interval.EndMarker : "must not have unhandled fixed intervals because all fixed intervals have a use at position 0"; spillBlockInactiveFixed(interval); spillCollectActiveAny(); spillCollectInactiveAny(interval); if (Debug.isLogEnabled()) { try (Indent indent2 = Debug.logAndIndent("state of registers:")) { for (Register register : availableRegs) { int i = register.number; try (Indent indent3 = Debug.logAndIndent( "reg %d: usePos: %d, blockPos: %d, intervals: ", i, usePos[i], blockPos[i])) { for (int j = 0; j < spillIntervals[i].size(); j++) { Debug.log("%d ", spillIntervals[i].get(j).operandNumber); } } } } } // the register must be free at least until this position boolean needSplit = blockPos[reg.number] <= interval.to(); int splitPos = blockPos[reg.number]; assert splitPos > 0 : "invalid splitPos"; assert needSplit || splitPos > interval.from() : "splitting interval at from"; Debug.log("assigning interval %s to %s", interval, reg); interval.assignLocation(reg.asValue(interval.kind())); if (needSplit) { // register not available for full interval : so split it splitWhenPartialRegisterAvailable(interval, splitPos); } // perform splitting and spilling for all affected intervals splitAndSpillIntersectingIntervals(reg); // activate interval activeLists.addToListSortedByCurrentFromPositions(RegisterBinding.Any, interval); interval.state = State.Active; }
@SuppressWarnings("unused") private static void printRegisterBindingList(RegisterBindingLists list, RegisterBinding binding) { for (Interval interval = list.get(binding); interval != Interval.EndMarker; interval = interval.next) { Debug.log("%s", interval); } }
@Override void walk() { try (Scope s = Debug.scope("OptimizingLinearScanWalker")) { for (AbstractBlock<?> block : allocator.sortedBlocks) { optimizeBlock(block); } } super.walk(); }
private void optimizeBlock(AbstractBlock<?> block) { if (block.getPredecessorCount() == 1) { int nextBlock = allocator.getFirstLirInstructionId(block); try (Scope s1 = Debug.scope("LSRAOptimization")) { Debug.log("next block: %s (%d)", block, nextBlock); } try (Indent indent0 = Debug.indent()) { walkTo(nextBlock); try (Scope s1 = Debug.scope("LSRAOptimization")) { boolean changed = true; // we need to do this because the active lists might change loop: while (changed) { changed = false; try (Indent indent1 = Debug.logAndIndent("Active intervals: (block %s [%d])", block, nextBlock)) { for (Interval active = activeLists.get(RegisterBinding.Any); active != Interval.EndMarker; active = active.next) { Debug.log("active (any): %s", active); if (optimize(nextBlock, block, active, RegisterBinding.Any)) { changed = true; break loop; } } for (Interval active = activeLists.get(RegisterBinding.Stack); active != Interval.EndMarker; active = active.next) { Debug.log("active (stack): %s", active); if (optimize(nextBlock, block, active, RegisterBinding.Stack)) { changed = true; break loop; } } } } } } } }
private boolean optimize( int currentPos, AbstractBlock<?> currentBlock, Interval currentInterval, RegisterBinding binding) { // BEGIN initialize and sanity checks assert currentBlock != null : "block must not be null"; assert currentInterval != null : "interval must not be null"; assert currentBlock.getPredecessorCount() == 1 : "more than one predecessors -> optimization not possible"; if (!currentInterval.isSplitChild()) { // interval is not a split child -> no need for optimization return false; } if (currentInterval.from() == currentPos) { // the interval starts at the current position so no need for splitting return false; } // get current location AllocatableValue currentLocation = currentInterval.location(); assert currentLocation != null : "active intervals must have a location assigned!"; // get predecessor stuff AbstractBlock<?> predecessorBlock = currentBlock.getPredecessors().get(0); int predEndId = allocator.getLastLirInstructionId(predecessorBlock); Interval predecessorInterval = currentInterval.getIntervalCoveringOpId(predEndId); assert predecessorInterval != null : "variable not live at the end of the only predecessor! " + predecessorBlock + " -> " + currentBlock + " interval: " + currentInterval; AllocatableValue predecessorLocation = predecessorInterval.location(); assert predecessorLocation != null : "handled intervals must have a location assigned!"; // END initialize and sanity checks if (currentLocation.equals(predecessorLocation)) { // locations are already equal -> nothing to optimize return false; } if (!isStackSlot(predecessorLocation) && !isRegister(predecessorLocation)) { assert predecessorInterval.canMaterialize(); // value is materialized -> no need for optimization return false; } assert isStackSlot(currentLocation) || isRegister(currentLocation) : "current location not a register or stack slot " + currentLocation; try (Indent indent = Debug.logAndIndent("location differs: %s vs. %s", predecessorLocation, currentLocation)) { // split current interval at current position Debug.log("splitting at position %d", currentPos); assert allocator.isBlockBegin(currentPos) && ((currentPos & 1) == 0) : "split pos must be even when on block boundary"; Interval splitPart = currentInterval.split(currentPos, allocator); activeLists.remove(binding, currentInterval); assert splitPart.from() >= currentPosition : "cannot append new interval before current walk position"; // the currentSplitChild is needed later when moves are inserted for reloading assert splitPart.currentSplitChild() == currentInterval : "overwriting wrong currentSplitChild"; splitPart.makeCurrentSplitChild(); if (Debug.isLogEnabled()) { Debug.log("left interval : %s", currentInterval.logString(allocator)); Debug.log("right interval : %s", splitPart.logString(allocator)); } if (Options.LSRAOptSplitOnly.getValue()) { // just add the split interval to the unhandled list unhandledLists.addToListSortedByStartAndUsePositions(RegisterBinding.Any, splitPart); } else { if (isRegister(predecessorLocation)) { splitRegisterInterval(splitPart, asRegister(predecessorLocation)); } else { assert isStackSlot(predecessorLocation); Debug.log("assigning interval %s to %s", splitPart, predecessorLocation); splitPart.assignLocation(predecessorLocation); // activate interval activeLists.addToListSortedByCurrentFromPositions(RegisterBinding.Stack, splitPart); splitPart.state = State.Active; splitStackInterval(splitPart); } } } return true; }