Mercurial > hg > truffle
view graal/com.oracle.graal.lir/src/com/oracle/graal/lir/FrameMap.java @ 13792:9e7acc9cad8e
kill unused frame states when loop exits are removed
thanks to Gilles
author | Andreas Woess <andreas.woess@jku.at> |
---|---|
date | Tue, 28 Jan 2014 23:38:22 +0100 |
parents | 34ab58984118 |
children | 599f1f616c3c |
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/* * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.graal.lir; import static com.oracle.graal.api.code.ValueUtil.*; import java.util.*; import com.oracle.graal.api.code.*; import com.oracle.graal.api.meta.*; import com.oracle.graal.asm.*; /** * This class is used to build the stack frame layout for a compiled method. A {@link StackSlot} is * used to index slots of the frame relative to the stack pointer. The frame size is only fixed * after register allocation when all spill slots have been allocated. Both the outgoing argument * area and the spill are can grow until then. Therefore, outgoing arguments are indexed from the * stack pointer, while spill slots are indexed from the beginning of the frame (and the total frame * size has to be added to get the actual offset from the stack pointer). */ public abstract class FrameMap { public final TargetDescription target; public final RegisterConfig registerConfig; /** * The final frame size, not including the size of the * {@link Architecture#getReturnAddressSize() return address slot}. The value is only set after * register allocation is complete, i.e., after all spill slots have been allocated. */ private int frameSize; /** * Initial size of the area occupied by spill slots and other stack-allocated memory blocks. */ protected int initialSpillSize; /** * Size of the area occupied by spill slots and other stack-allocated memory blocks. */ protected int spillSize; /** * Size of the area occupied by outgoing overflow arguments. This value is adjusted as calling * conventions for outgoing calls are retrieved. On some platforms, there is a minimum outgoing * size even if no overflow arguments are on the stack. */ protected int outgoingSize; /** * Determines if this frame has values on the stack for outgoing calls. */ private boolean hasOutgoingStackArguments; /** * The list of stack slots allocated in this frame that are present in every reference map. */ private final List<StackSlot> objectStackSlots; /** * Records whether an offset to an incoming stack argument was ever returned by * {@link #offsetForStackSlot(StackSlot)}. */ private boolean accessesCallerFrame; /** * Creates a new frame map for the specified method. */ public FrameMap(CodeCacheProvider codeCache) { this.target = codeCache.getTarget(); this.registerConfig = codeCache.getRegisterConfig(); this.frameSize = -1; this.outgoingSize = codeCache.getMinimumOutgoingSize(); this.objectStackSlots = new ArrayList<>(); } protected int returnAddressSize() { return target.arch.getReturnAddressSize(); } protected int calleeSaveAreaSize() { CalleeSaveLayout csl = registerConfig.getCalleeSaveLayout(); return csl != null ? csl.size : 0; } /** * Determines if an offset to an incoming stack argument was ever returned by * {@link #offsetForStackSlot(StackSlot)}. */ public boolean accessesCallerFrame() { return accessesCallerFrame; } /** * Gets the frame size of the compiled frame, not including the size of the * {@link Architecture#getReturnAddressSize() return address slot}. * * @return The size of the frame (in bytes). */ public int frameSize() { assert frameSize != -1 : "frame size not computed yet"; return frameSize; } /** * Determines if any space is used in the frame apart from the * {@link Architecture#getReturnAddressSize() return address slot}. */ public boolean frameNeedsAllocating() { int unalignedFrameSize = spillSize - returnAddressSize(); return hasOutgoingStackArguments || unalignedFrameSize != 0; } /** * Gets the total frame size of the compiled frame, including the size of the * {@link Architecture#getReturnAddressSize() return address slot}. * * @return The total size of the frame (in bytes). */ public abstract int totalFrameSize(); /** * Gets the current size of this frame. This is the size that would be returned by * {@link #frameSize()} if {@link #finish()} were called now. */ public abstract int currentFrameSize(); /** * Aligns the given frame size to the stack alignment size and return the aligned size. * * @param size the initial frame size to be aligned * @return the aligned frame size */ protected abstract int alignFrameSize(int size); /** * Computes the final size of this frame. After this method has been called, methods that change * the frame size cannot be called anymore, e.g., no more spill slots or outgoing arguments can * be requested. */ public void finish() { assert this.frameSize == -1 : "must only be set once"; if (freedSlots != null) { // If the freed slots cover the complete spill area (except for the return // address slot), then the spill size is reset to its initial value. // Without this, frameNeedsAllocating() would never return true. int total = 0; for (StackSlot s : freedSlots) { total += target.arch.getSizeInBytes(s.getKind()); } if (total == spillSize - initialSpillSize) { // reset spill area size spillSize = initialSpillSize; } freedSlots = null; } frameSize = currentFrameSize(); } /** * Computes the offset of a stack slot relative to the frame register. * * @param slot a stack slot * @return the offset of the stack slot */ public int offsetForStackSlot(StackSlot slot) { assert (!slot.getRawAddFrameSize() && slot.getRawOffset() < outgoingSize) || (slot.getRawAddFrameSize() && slot.getRawOffset() < 0 && -slot.getRawOffset() <= spillSize) || (slot.getRawAddFrameSize() && slot.getRawOffset() >= 0); if (slot.isInCallerFrame()) { accessesCallerFrame = true; } return slot.getOffset(totalFrameSize()); } /** * Computes the index of a stack slot relative to slot 0. This is also the bit index of stack * slots in the reference map. * * @param slot a stack slot * @return the index of the stack slot */ public int indexForStackSlot(StackSlot slot) { assert offsetForStackSlot(slot) % target.wordSize == 0; return offsetForStackSlot(slot) / target.wordSize; } /** * Gets the offset from the stack pointer to the stack area where callee-saved registers are * stored. * * @return The offset to the callee save area (in bytes). */ public abstract int offsetToCalleeSaveArea(); /** * Informs the frame map that the compiled code calls a particular method, which may need stack * space for outgoing arguments. * * @param cc The calling convention for the called method. */ public void callsMethod(CallingConvention cc) { reserveOutgoing(cc.getStackSize()); } /** * Reserves space for stack-based outgoing arguments. * * @param argsSize The amount of space (in bytes) to reserve for stack-based outgoing arguments. */ public void reserveOutgoing(int argsSize) { assert frameSize == -1 : "frame size must not yet be fixed"; outgoingSize = Math.max(outgoingSize, argsSize); hasOutgoingStackArguments = hasOutgoingStackArguments || argsSize > 0; } /** * Reserves a new spill slot in the frame of the method being compiled. The returned slot is * aligned on its natural alignment, i.e., an 8-byte spill slot is aligned at an 8-byte * boundary. * * @param kind The kind of the spill slot to be reserved. * @param additionalOffset * @return A spill slot denoting the reserved memory area. */ protected abstract StackSlot allocateNewSpillSlot(PlatformKind kind, int additionalOffset); /** * Returns the spill slot size for the given {@link PlatformKind}. The default value is the size * in bytes for the target architecture. * * @param kind the {@link PlatformKind} to be stored in the spill slot. * @return the size in bytes */ protected int spillSlotSize(PlatformKind kind) { return target.arch.getSizeInBytes(kind); } /** * Reserves a spill slot in the frame of the method being compiled. The returned slot is aligned * on its natural alignment, i.e., an 8-byte spill slot is aligned at an 8-byte boundary, unless * overridden by a subclass. * * @param kind The kind of the spill slot to be reserved. * @return A spill slot denoting the reserved memory area. */ public StackSlot allocateSpillSlot(PlatformKind kind) { assert frameSize == -1 : "frame size must not yet be fixed"; if (freedSlots != null) { for (Iterator<StackSlot> iter = freedSlots.iterator(); iter.hasNext();) { StackSlot s = iter.next(); if (s.getPlatformKind() == kind) { iter.remove(); if (freedSlots.isEmpty()) { freedSlots = null; } return s; } } } int size = spillSlotSize(kind); spillSize = NumUtil.roundUp(spillSize + size, size); return allocateNewSpillSlot(kind, 0); } private Set<StackSlot> freedSlots; /** * Frees a spill slot that was obtained via {@link #allocateSpillSlot(PlatformKind)} such that * it can be reused for the next allocation request for the same kind of slot. */ public void freeSpillSlot(StackSlot slot) { if (freedSlots == null) { freedSlots = new HashSet<>(); } freedSlots.add(slot); } /** * Reserves a number of contiguous slots in the frame of the method being compiled. If the * requested number of slots is 0, this method returns {@code null}. * * @param slots the number of slots to reserve * @param objects specifies the indexes of the object pointer slots. The caller is responsible * for guaranteeing that each such object pointer slot is initialized before any * instruction that uses a reference map. Without this guarantee, the garbage * collector could see garbage object values. * @param outObjectStackSlots if non-null, the object pointer slots allocated are added to this * list * @return the first reserved stack slot (i.e., at the lowest address) */ public StackSlot allocateStackSlots(int slots, BitSet objects, List<StackSlot> outObjectStackSlots) { assert frameSize == -1 : "frame size must not yet be fixed"; if (slots == 0) { return null; } spillSize += (slots * target.wordSize); if (!objects.isEmpty()) { assert objects.length() <= slots; StackSlot result = null; for (int slotIndex = 0; slotIndex < slots; slotIndex++) { StackSlot objectSlot = null; if (objects.get(slotIndex)) { objectSlot = allocateNewSpillSlot(Kind.Object, slotIndex * target.wordSize); objectStackSlots.add(objectSlot); if (outObjectStackSlots != null) { outObjectStackSlots.add(objectSlot); } } if (slotIndex == 0) { if (objectSlot != null) { result = objectSlot; } else { result = allocateNewSpillSlot(target.wordKind, 0); } } } assert result != null; return result; } else { return allocateNewSpillSlot(target.wordKind, 0); } } public ReferenceMap initReferenceMap(boolean canHaveRegisters) { ReferenceMap refMap = new ReferenceMap(canHaveRegisters ? target.arch.getRegisterReferenceMapBitCount() : 0, frameSize() / target.wordSize); for (StackSlot slot : objectStackSlots) { setReference(slot, refMap); } return refMap; } /** * Marks the specified location as a reference in the reference map of the debug information. * The tracked location can be a {@link RegisterValue} or a {@link StackSlot}. Note that a * {@link Constant} is automatically tracked. * * @param location The location to be added to the reference map. * @param refMap A reference map, as created by {@link #initReferenceMap(boolean)}. */ public void setReference(Value location, ReferenceMap refMap) { Kind kind = location.getKind(); if (kind == Kind.Object || kind == Kind.NarrowOop) { if (isRegister(location)) { refMap.setRegister(asRegister(location).number, kind == Kind.NarrowOop); } else if (isStackSlot(location)) { if (kind == Kind.NarrowOop) { int offset = offsetForStackSlot(asStackSlot(location)); assert offset % target.wordSize == 0 || offset % target.wordSize == target.wordSize / 2; refMap.setStackSlot(offset / target.wordSize, offset % target.wordSize == 0, offset % target.wordSize != 0); } else { int index = indexForStackSlot(asStackSlot(location)); refMap.setStackSlot(index, false, false); } } else { assert isConstant(location); } } } }