2010-08-14 08:15:52 +08:00
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//===- LocalStackSlotAllocation.cpp - Pre-allocate locals to stack slots --===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass assigns local frame indices to stack slots relative to one another
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// and allocates additional base registers to access them when the target
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2011-01-07 12:58:58 +08:00
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// estimates they are likely to be out of range of stack pointer and frame
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2010-08-14 08:15:52 +08:00
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// pointer relative addressing.
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//
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//===----------------------------------------------------------------------===//
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2013-12-19 11:17:11 +08:00
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#include "llvm/ADT/SetVector.h"
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2012-12-04 00:50:05 +08:00
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#include "llvm/ADT/SmallSet.h"
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2017-10-11 06:33:29 +08:00
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#include "llvm/ADT/SmallVector.h"
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2012-12-04 00:50:05 +08:00
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#include "llvm/ADT/Statistic.h"
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2017-10-11 06:33:29 +08:00
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#include "llvm/CodeGen/MachineBasicBlock.h"
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2012-12-04 00:50:05 +08:00
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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2017-10-11 06:33:29 +08:00
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineOperand.h"
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2012-12-04 00:50:05 +08:00
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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2013-12-19 11:17:11 +08:00
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#include "llvm/CodeGen/StackProtector.h"
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2017-11-17 09:07:10 +08:00
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#include "llvm/CodeGen/TargetFrameLowering.h"
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#include "llvm/CodeGen/TargetOpcodes.h"
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#include "llvm/CodeGen/TargetRegisterInfo.h"
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#include "llvm/CodeGen/TargetSubtargetInfo.h"
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2010-08-14 08:15:52 +08:00
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#include "llvm/Pass.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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2017-10-11 06:33:29 +08:00
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#include <algorithm>
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#include <cassert>
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#include <cstdint>
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#include <tuple>
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2010-08-14 08:15:52 +08:00
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using namespace llvm;
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2014-04-22 10:02:50 +08:00
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#define DEBUG_TYPE "localstackalloc"
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2010-08-18 02:13:53 +08:00
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STATISTIC(NumAllocations, "Number of frame indices allocated into local block");
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STATISTIC(NumBaseRegisters, "Number of virtual frame base registers allocated");
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STATISTIC(NumReplacements, "Number of frame indices references replaced");
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2010-08-14 08:15:52 +08:00
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namespace {
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2017-10-11 06:33:29 +08:00
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2010-09-01 01:58:19 +08:00
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class FrameRef {
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MachineBasicBlock::iterator MI; // Instr referencing the frame
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int64_t LocalOffset; // Local offset of the frame idx referenced
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2013-05-01 04:04:37 +08:00
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int FrameIdx; // The frame index
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2016-10-26 22:53:50 +08:00
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// Order reference instruction appears in program. Used to ensure
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// deterministic order when multiple instructions may reference the same
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// location.
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unsigned Order;
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2010-09-01 01:58:19 +08:00
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public:
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2016-10-26 22:53:50 +08:00
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FrameRef(MachineInstr *I, int64_t Offset, int Idx, unsigned Ord) :
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MI(I), LocalOffset(Offset), FrameIdx(Idx), Order(Ord) {}
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2010-09-01 01:58:19 +08:00
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bool operator<(const FrameRef &RHS) const {
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2016-10-26 22:53:50 +08:00
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return std::tie(LocalOffset, FrameIdx, Order) <
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std::tie(RHS.LocalOffset, RHS.FrameIdx, RHS.Order);
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2010-09-01 01:58:19 +08:00
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}
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2016-10-26 22:53:50 +08:00
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2013-05-01 04:04:37 +08:00
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MachineBasicBlock::iterator getMachineInstr() const { return MI; }
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int64_t getLocalOffset() const { return LocalOffset; }
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int getFrameIndex() const { return FrameIdx; }
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2010-09-01 01:58:19 +08:00
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};
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2010-08-14 08:15:52 +08:00
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class LocalStackSlotPass: public MachineFunctionPass {
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2017-10-11 06:33:29 +08:00
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SmallVector<int64_t, 16> LocalOffsets;
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2013-12-19 11:17:11 +08:00
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/// StackObjSet - A set of stack object indexes
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2017-10-11 06:33:29 +08:00
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using StackObjSet = SmallSetVector<int, 8>;
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2010-08-18 02:13:53 +08:00
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2016-07-29 02:40:00 +08:00
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void AdjustStackOffset(MachineFrameInfo &MFI, int FrameIdx, int64_t &Offset,
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2010-08-24 04:40:38 +08:00
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bool StackGrowsDown, unsigned &MaxAlign);
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2013-12-19 11:17:11 +08:00
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void AssignProtectedObjSet(const StackObjSet &UnassignedObjs,
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SmallSet<int, 16> &ProtectedObjs,
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2016-07-29 02:40:00 +08:00
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MachineFrameInfo &MFI, bool StackGrowsDown,
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2013-12-19 11:17:11 +08:00
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int64_t &Offset, unsigned &MaxAlign);
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2010-08-19 06:44:49 +08:00
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void calculateFrameObjectOffsets(MachineFunction &Fn);
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2010-08-21 00:48:30 +08:00
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bool insertFrameReferenceRegisters(MachineFunction &Fn);
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2017-10-11 06:33:29 +08:00
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2010-08-14 08:15:52 +08:00
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public:
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static char ID; // Pass identification, replacement for typeid
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2017-10-11 06:33:29 +08:00
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2016-10-26 22:53:50 +08:00
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explicit LocalStackSlotPass() : MachineFunctionPass(ID) {
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2013-12-19 11:17:11 +08:00
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initializeLocalStackSlotPassPass(*PassRegistry::getPassRegistry());
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}
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2017-10-11 06:33:29 +08:00
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2014-03-07 17:26:03 +08:00
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bool runOnMachineFunction(MachineFunction &MF) override;
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2010-08-14 08:15:52 +08:00
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2014-03-07 17:26:03 +08:00
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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2010-08-14 08:15:52 +08:00
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AU.setPreservesCFG();
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2013-12-19 11:17:11 +08:00
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AU.addRequired<StackProtector>();
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2010-08-14 08:15:52 +08:00
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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};
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2017-10-11 06:33:29 +08:00
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2010-08-14 08:15:52 +08:00
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} // end anonymous namespace
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char LocalStackSlotPass::ID = 0;
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2017-10-11 06:33:29 +08:00
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2012-02-09 05:23:13 +08:00
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char &llvm::LocalStackSlotAllocationID = LocalStackSlotPass::ID;
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2017-10-11 06:33:29 +08:00
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2017-05-26 05:26:32 +08:00
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INITIALIZE_PASS_BEGIN(LocalStackSlotPass, DEBUG_TYPE,
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2013-12-19 11:17:11 +08:00
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"Local Stack Slot Allocation", false, false)
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INITIALIZE_PASS_DEPENDENCY(StackProtector)
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2017-05-26 05:26:32 +08:00
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INITIALIZE_PASS_END(LocalStackSlotPass, DEBUG_TYPE,
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2013-12-19 11:17:11 +08:00
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"Local Stack Slot Allocation", false, false)
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2010-08-14 08:15:52 +08:00
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bool LocalStackSlotPass::runOnMachineFunction(MachineFunction &MF) {
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2016-07-29 02:40:00 +08:00
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MachineFrameInfo &MFI = MF.getFrameInfo();
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2014-08-05 10:39:49 +08:00
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const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
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2016-07-29 02:40:00 +08:00
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unsigned LocalObjectCount = MFI.getObjectIndexEnd();
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2010-08-19 06:44:49 +08:00
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2010-08-25 03:05:43 +08:00
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// If the target doesn't want/need this pass, or if there are no locals
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// to consider, early exit.
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if (!TRI->requiresVirtualBaseRegisters(MF) || LocalObjectCount == 0)
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2010-08-19 06:44:49 +08:00
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return true;
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// Make sure we have enough space to store the local offsets.
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2016-07-29 02:40:00 +08:00
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LocalOffsets.resize(MFI.getObjectIndexEnd());
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2010-08-19 06:44:49 +08:00
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2010-08-18 02:13:53 +08:00
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// Lay out the local blob.
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2010-08-14 08:15:52 +08:00
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calculateFrameObjectOffsets(MF);
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2010-08-18 02:13:53 +08:00
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// Insert virtual base registers to resolve frame index references.
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2010-08-21 00:48:30 +08:00
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bool UsedBaseRegs = insertFrameReferenceRegisters(MF);
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2010-08-19 06:44:49 +08:00
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2010-08-19 10:47:08 +08:00
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// Tell MFI whether any base registers were allocated. PEI will only
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// want to use the local block allocations from this pass if there were any.
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// Otherwise, PEI can do a bit better job of getting the alignment right
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// without a hole at the start since it knows the alignment of the stack
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// at the start of local allocation, and this pass doesn't.
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2016-07-29 02:40:00 +08:00
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MFI.setUseLocalStackAllocationBlock(UsedBaseRegs);
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2010-08-19 10:47:08 +08:00
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2010-08-14 08:15:52 +08:00
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return true;
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}
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/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
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2016-07-29 02:40:00 +08:00
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void LocalStackSlotPass::AdjustStackOffset(MachineFrameInfo &MFI,
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2010-08-19 06:44:49 +08:00
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int FrameIdx, int64_t &Offset,
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2010-08-24 04:40:38 +08:00
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bool StackGrowsDown,
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2010-08-19 06:44:49 +08:00
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unsigned &MaxAlign) {
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2010-08-24 04:40:38 +08:00
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// If the stack grows down, add the object size to find the lowest address.
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if (StackGrowsDown)
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2016-07-29 02:40:00 +08:00
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Offset += MFI.getObjectSize(FrameIdx);
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2010-08-24 04:40:38 +08:00
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2016-07-29 02:40:00 +08:00
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unsigned Align = MFI.getObjectAlignment(FrameIdx);
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2010-08-14 08:15:52 +08:00
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// If the alignment of this object is greater than that of the stack, then
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// increase the stack alignment to match.
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MaxAlign = std::max(MaxAlign, Align);
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// Adjust to alignment boundary.
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Offset = (Offset + Align - 1) / Align * Align;
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2010-08-24 04:40:38 +08:00
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int64_t LocalOffset = StackGrowsDown ? -Offset : Offset;
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2010-08-14 08:15:52 +08:00
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DEBUG(dbgs() << "Allocate FI(" << FrameIdx << ") to local offset "
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2010-08-24 04:40:38 +08:00
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<< LocalOffset << "\n");
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2010-08-19 06:44:49 +08:00
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// Keep the offset available for base register allocation
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2010-08-24 04:40:38 +08:00
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LocalOffsets[FrameIdx] = LocalOffset;
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2010-08-19 06:44:49 +08:00
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// And tell MFI about it for PEI to use later
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2016-07-29 02:40:00 +08:00
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MFI.mapLocalFrameObject(FrameIdx, LocalOffset);
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2010-08-24 04:40:38 +08:00
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if (!StackGrowsDown)
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2016-07-29 02:40:00 +08:00
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Offset += MFI.getObjectSize(FrameIdx);
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2010-08-14 08:15:52 +08:00
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++NumAllocations;
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}
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2013-12-19 11:17:11 +08:00
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/// AssignProtectedObjSet - Helper function to assign large stack objects (i.e.,
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/// those required to be close to the Stack Protector) to stack offsets.
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void LocalStackSlotPass::AssignProtectedObjSet(const StackObjSet &UnassignedObjs,
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SmallSet<int, 16> &ProtectedObjs,
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2016-07-29 02:40:00 +08:00
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MachineFrameInfo &MFI,
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2013-12-19 11:17:11 +08:00
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bool StackGrowsDown, int64_t &Offset,
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unsigned &MaxAlign) {
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for (StackObjSet::const_iterator I = UnassignedObjs.begin(),
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E = UnassignedObjs.end(); I != E; ++I) {
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int i = *I;
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AdjustStackOffset(MFI, i, Offset, StackGrowsDown, MaxAlign);
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ProtectedObjs.insert(i);
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}
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}
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2010-08-14 08:15:52 +08:00
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/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
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/// abstract stack objects.
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void LocalStackSlotPass::calculateFrameObjectOffsets(MachineFunction &Fn) {
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// Loop over all of the stack objects, assigning sequential addresses...
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2016-07-29 02:40:00 +08:00
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MachineFrameInfo &MFI = Fn.getFrameInfo();
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2014-08-05 10:39:49 +08:00
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const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
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2010-08-24 04:40:38 +08:00
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bool StackGrowsDown =
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2011-01-10 20:39:04 +08:00
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TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
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2010-08-14 08:15:52 +08:00
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int64_t Offset = 0;
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2010-08-17 06:30:41 +08:00
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unsigned MaxAlign = 0;
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2013-12-19 11:17:11 +08:00
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StackProtector *SP = &getAnalysis<StackProtector>();
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2010-08-14 08:15:52 +08:00
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// Make sure that the stack protector comes before the local variables on the
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// stack.
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2013-12-19 11:17:11 +08:00
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SmallSet<int, 16> ProtectedObjs;
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2016-07-29 02:40:00 +08:00
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if (MFI.getStackProtectorIndex() >= 0) {
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2013-12-19 11:17:11 +08:00
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StackObjSet LargeArrayObjs;
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2014-02-01 09:36:16 +08:00
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StackObjSet SmallArrayObjs;
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StackObjSet AddrOfObjs;
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2016-07-29 02:40:00 +08:00
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AdjustStackOffset(MFI, MFI.getStackProtectorIndex(), Offset,
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2010-08-24 04:40:38 +08:00
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StackGrowsDown, MaxAlign);
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2010-08-14 08:15:52 +08:00
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// Assign large stack objects first.
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2016-07-29 02:40:00 +08:00
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for (unsigned i = 0, e = MFI.getObjectIndexEnd(); i != e; ++i) {
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if (MFI.isDeadObjectIndex(i))
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2010-08-14 08:15:52 +08:00
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continue;
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2016-07-29 02:40:00 +08:00
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if (MFI.getStackProtectorIndex() == (int)i)
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2010-08-14 08:15:52 +08:00
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continue;
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2016-07-29 02:40:00 +08:00
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switch (SP->getSSPLayout(MFI.getObjectAllocation(i))) {
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2013-12-19 11:17:11 +08:00
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case StackProtector::SSPLK_None:
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2014-02-01 09:36:16 +08:00
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continue;
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2013-12-19 11:17:11 +08:00
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case StackProtector::SSPLK_SmallArray:
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2014-02-01 09:36:16 +08:00
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SmallArrayObjs.insert(i);
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continue;
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2013-12-19 11:17:11 +08:00
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case StackProtector::SSPLK_AddrOf:
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2014-02-01 09:36:16 +08:00
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AddrOfObjs.insert(i);
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2013-12-19 11:17:11 +08:00
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continue;
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case StackProtector::SSPLK_LargeArray:
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LargeArrayObjs.insert(i);
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continue;
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}
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llvm_unreachable("Unexpected SSPLayoutKind.");
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2010-08-14 08:15:52 +08:00
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}
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2013-12-19 11:17:11 +08:00
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AssignProtectedObjSet(LargeArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
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Offset, MaxAlign);
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2014-02-01 09:36:16 +08:00
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AssignProtectedObjSet(SmallArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
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Offset, MaxAlign);
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AssignProtectedObjSet(AddrOfObjs, ProtectedObjs, MFI, StackGrowsDown,
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Offset, MaxAlign);
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2010-08-14 08:15:52 +08:00
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}
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// Then assign frame offsets to stack objects that are not used to spill
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// callee saved registers.
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2016-07-29 02:40:00 +08:00
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for (unsigned i = 0, e = MFI.getObjectIndexEnd(); i != e; ++i) {
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if (MFI.isDeadObjectIndex(i))
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2010-08-14 08:15:52 +08:00
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continue;
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2016-07-29 02:40:00 +08:00
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if (MFI.getStackProtectorIndex() == (int)i)
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2010-08-14 08:15:52 +08:00
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continue;
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2013-12-19 11:17:11 +08:00
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if (ProtectedObjs.count(i))
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2010-08-14 08:15:52 +08:00
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continue;
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2010-08-24 04:40:38 +08:00
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|
|
AdjustStackOffset(MFI, i, Offset, StackGrowsDown, MaxAlign);
|
2010-08-14 08:15:52 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
// Remember how big this blob of stack space is
|
2016-07-29 02:40:00 +08:00
|
|
|
MFI.setLocalFrameSize(Offset);
|
|
|
|
MFI.setLocalFrameMaxAlign(MaxAlign);
|
2010-08-14 08:15:52 +08:00
|
|
|
}
|
2010-08-18 02:13:53 +08:00
|
|
|
|
2010-08-19 01:57:37 +08:00
|
|
|
static inline bool
|
2015-03-21 01:20:07 +08:00
|
|
|
lookupCandidateBaseReg(unsigned BaseReg,
|
|
|
|
int64_t BaseOffset,
|
2010-08-24 04:40:38 +08:00
|
|
|
int64_t FrameSizeAdjust,
|
2010-08-19 06:44:49 +08:00
|
|
|
int64_t LocalFrameOffset,
|
2016-07-01 07:39:46 +08:00
|
|
|
const MachineInstr &MI,
|
2010-08-19 01:57:37 +08:00
|
|
|
const TargetRegisterInfo *TRI) {
|
2013-05-01 04:04:37 +08:00
|
|
|
// Check if the relative offset from the where the base register references
|
|
|
|
// to the target address is in range for the instruction.
|
|
|
|
int64_t Offset = FrameSizeAdjust + LocalFrameOffset - BaseOffset;
|
2016-07-01 07:39:46 +08:00
|
|
|
return TRI->isFrameOffsetLegal(&MI, BaseReg, Offset);
|
2010-08-19 01:57:37 +08:00
|
|
|
}
|
|
|
|
|
2010-08-21 00:48:30 +08:00
|
|
|
bool LocalStackSlotPass::insertFrameReferenceRegisters(MachineFunction &Fn) {
|
2010-08-18 02:13:53 +08:00
|
|
|
// Scan the function's instructions looking for frame index references.
|
|
|
|
// For each, ask the target if it wants a virtual base register for it
|
|
|
|
// based on what we can tell it about where the local will end up in the
|
|
|
|
// stack frame. If it wants one, re-use a suitable one we've previously
|
|
|
|
// allocated, or if there isn't one that fits the bill, allocate a new one
|
|
|
|
// and ask the target to create a defining instruction for it.
|
2010-08-21 00:48:30 +08:00
|
|
|
bool UsedBaseReg = false;
|
2010-08-18 02:13:53 +08:00
|
|
|
|
2016-07-29 02:40:00 +08:00
|
|
|
MachineFrameInfo &MFI = Fn.getFrameInfo();
|
2014-08-05 10:39:49 +08:00
|
|
|
const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
|
|
|
|
const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
|
2010-08-21 04:25:31 +08:00
|
|
|
bool StackGrowsDown =
|
2011-01-10 20:39:04 +08:00
|
|
|
TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
|
2010-08-18 02:13:53 +08:00
|
|
|
|
2010-09-01 01:58:19 +08:00
|
|
|
// Collect all of the instructions in the block that reference
|
|
|
|
// a frame index. Also store the frame index referenced to ease later
|
|
|
|
// lookup. (For any insn that has more than one FI reference, we arbitrarily
|
|
|
|
// choose the first one).
|
|
|
|
SmallVector<FrameRef, 64> FrameReferenceInsns;
|
2010-08-19 06:44:49 +08:00
|
|
|
|
2016-10-26 22:53:50 +08:00
|
|
|
unsigned Order = 0;
|
|
|
|
|
2016-07-01 07:39:46 +08:00
|
|
|
for (MachineBasicBlock &BB : Fn) {
|
|
|
|
for (MachineInstr &MI : BB) {
|
2013-11-29 14:35:30 +08:00
|
|
|
// Debug value, stackmap and patchpoint instructions can't be out of
|
|
|
|
// range, so they don't need any updates.
|
2016-07-01 07:39:46 +08:00
|
|
|
if (MI.isDebugValue() || MI.getOpcode() == TargetOpcode::STATEPOINT ||
|
|
|
|
MI.getOpcode() == TargetOpcode::STACKMAP ||
|
|
|
|
MI.getOpcode() == TargetOpcode::PATCHPOINT)
|
2010-08-18 06:41:55 +08:00
|
|
|
continue;
|
2010-12-18 07:09:14 +08:00
|
|
|
|
2010-08-18 02:13:53 +08:00
|
|
|
// For now, allocate the base register(s) within the basic block
|
|
|
|
// where they're used, and don't try to keep them around outside
|
|
|
|
// of that. It may be beneficial to try sharing them more broadly
|
|
|
|
// than that, but the increased register pressure makes that a
|
|
|
|
// tricky thing to balance. Investigate if re-materializing these
|
|
|
|
// becomes an issue.
|
2016-07-01 07:39:46 +08:00
|
|
|
for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
|
2010-08-18 02:13:53 +08:00
|
|
|
// Consider replacing all frame index operands that reference
|
|
|
|
// an object allocated in the local block.
|
2016-07-01 07:39:46 +08:00
|
|
|
if (MI.getOperand(i).isFI()) {
|
2010-08-18 06:41:55 +08:00
|
|
|
// Don't try this with values not in the local block.
|
2016-07-29 02:40:00 +08:00
|
|
|
if (!MFI.isObjectPreAllocated(MI.getOperand(i).getIndex()))
|
2010-09-01 01:58:19 +08:00
|
|
|
break;
|
2016-07-01 07:39:46 +08:00
|
|
|
int Idx = MI.getOperand(i).getIndex();
|
2013-05-01 04:04:37 +08:00
|
|
|
int64_t LocalOffset = LocalOffsets[Idx];
|
2016-07-01 07:39:46 +08:00
|
|
|
if (!TRI->needsFrameBaseReg(&MI, LocalOffset))
|
2013-05-01 04:04:37 +08:00
|
|
|
break;
|
2016-10-26 22:53:50 +08:00
|
|
|
FrameReferenceInsns.push_back(FrameRef(&MI, LocalOffset, Idx, Order++));
|
2010-09-01 01:58:19 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2010-12-18 07:09:14 +08:00
|
|
|
|
2016-10-18 08:11:19 +08:00
|
|
|
// Sort the frame references by local offset.
|
|
|
|
// Use frame index as a tie-breaker in case MI's have the same offset.
|
|
|
|
std::sort(FrameReferenceInsns.begin(), FrameReferenceInsns.end());
|
2010-09-01 01:58:19 +08:00
|
|
|
|
2015-10-10 03:13:58 +08:00
|
|
|
MachineBasicBlock *Entry = &Fn.front();
|
2010-09-01 01:58:19 +08:00
|
|
|
|
2013-05-01 04:04:37 +08:00
|
|
|
unsigned BaseReg = 0;
|
|
|
|
int64_t BaseOffset = 0;
|
|
|
|
|
2010-12-18 07:09:14 +08:00
|
|
|
// Loop through the frame references and allocate for them as necessary.
|
2010-09-01 01:58:19 +08:00
|
|
|
for (int ref = 0, e = FrameReferenceInsns.size(); ref < e ; ++ref) {
|
2013-05-01 04:04:37 +08:00
|
|
|
FrameRef &FR = FrameReferenceInsns[ref];
|
2016-07-01 07:39:46 +08:00
|
|
|
MachineInstr &MI = *FR.getMachineInstr();
|
2013-05-01 04:04:37 +08:00
|
|
|
int64_t LocalOffset = FR.getLocalOffset();
|
|
|
|
int FrameIdx = FR.getFrameIndex();
|
2016-07-29 02:40:00 +08:00
|
|
|
assert(MFI.isObjectPreAllocated(FrameIdx) &&
|
2013-05-01 04:04:37 +08:00
|
|
|
"Only pre-allocated locals expected!");
|
|
|
|
|
2016-07-01 07:39:46 +08:00
|
|
|
DEBUG(dbgs() << "Considering: " << MI);
|
2013-05-01 04:04:37 +08:00
|
|
|
|
|
|
|
unsigned idx = 0;
|
2016-07-01 07:39:46 +08:00
|
|
|
for (unsigned f = MI.getNumOperands(); idx != f; ++idx) {
|
|
|
|
if (!MI.getOperand(idx).isFI())
|
2013-05-01 04:04:37 +08:00
|
|
|
continue;
|
|
|
|
|
2016-07-01 07:39:46 +08:00
|
|
|
if (FrameIdx == MI.getOperand(idx).getIndex())
|
2013-05-01 04:04:37 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
2016-07-01 07:39:46 +08:00
|
|
|
assert(idx < MI.getNumOperands() && "Cannot find FI operand");
|
2013-05-01 04:04:37 +08:00
|
|
|
|
|
|
|
int64_t Offset = 0;
|
2016-07-29 02:40:00 +08:00
|
|
|
int64_t FrameSizeAdjust = StackGrowsDown ? MFI.getLocalFrameSize() : 0;
|
2013-05-01 04:04:37 +08:00
|
|
|
|
2016-07-01 07:39:46 +08:00
|
|
|
DEBUG(dbgs() << " Replacing FI in: " << MI);
|
2013-05-01 04:04:37 +08:00
|
|
|
|
|
|
|
// If we have a suitable base register available, use it; otherwise
|
|
|
|
// create a new one. Note that any offset encoded in the
|
|
|
|
// instruction itself will be taken into account by the target,
|
|
|
|
// so we don't have to adjust for it here when reusing a base
|
|
|
|
// register.
|
2016-07-01 07:39:46 +08:00
|
|
|
if (UsedBaseReg &&
|
|
|
|
lookupCandidateBaseReg(BaseReg, BaseOffset, FrameSizeAdjust,
|
|
|
|
LocalOffset, MI, TRI)) {
|
2013-05-01 04:04:37 +08:00
|
|
|
DEBUG(dbgs() << " Reusing base register " << BaseReg << "\n");
|
|
|
|
// We found a register to reuse.
|
|
|
|
Offset = FrameSizeAdjust + LocalOffset - BaseOffset;
|
|
|
|
} else {
|
2016-07-01 07:39:46 +08:00
|
|
|
// No previously defined register was in range, so create a new one.
|
|
|
|
int64_t InstrOffset = TRI->getFrameIndexInstrOffset(&MI, idx);
|
2013-05-01 04:04:37 +08:00
|
|
|
|
|
|
|
int64_t PrevBaseOffset = BaseOffset;
|
|
|
|
BaseOffset = FrameSizeAdjust + LocalOffset + InstrOffset;
|
|
|
|
|
|
|
|
// We'd like to avoid creating single-use virtual base registers.
|
|
|
|
// Because the FrameRefs are in sorted order, and we've already
|
|
|
|
// processed all FrameRefs before this one, just check whether or not
|
|
|
|
// the next FrameRef will be able to reuse this new register. If not,
|
|
|
|
// then don't bother creating it.
|
2014-02-23 21:34:21 +08:00
|
|
|
if (ref + 1 >= e ||
|
|
|
|
!lookupCandidateBaseReg(
|
2015-03-21 01:20:07 +08:00
|
|
|
BaseReg, BaseOffset, FrameSizeAdjust,
|
2014-02-23 21:34:21 +08:00
|
|
|
FrameReferenceInsns[ref + 1].getLocalOffset(),
|
2016-07-01 07:39:46 +08:00
|
|
|
*FrameReferenceInsns[ref + 1].getMachineInstr(), TRI)) {
|
2013-05-01 04:04:37 +08:00
|
|
|
BaseOffset = PrevBaseOffset;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
2017-10-11 07:50:49 +08:00
|
|
|
const MachineFunction *MF = MI.getMF();
|
2013-05-01 04:04:37 +08:00
|
|
|
const TargetRegisterClass *RC = TRI->getPointerRegClass(*MF);
|
|
|
|
BaseReg = Fn.getRegInfo().createVirtualRegister(RC);
|
|
|
|
|
|
|
|
DEBUG(dbgs() << " Materializing base register " << BaseReg <<
|
|
|
|
" at frame local offset " << LocalOffset + InstrOffset << "\n");
|
|
|
|
|
|
|
|
// Tell the target to insert the instruction to initialize
|
|
|
|
// the base register.
|
|
|
|
// MachineBasicBlock::iterator InsertionPt = Entry->begin();
|
|
|
|
TRI->materializeFrameBaseRegister(Entry, BaseReg, FrameIdx,
|
|
|
|
InstrOffset);
|
|
|
|
|
|
|
|
// The base register already includes any offset specified
|
|
|
|
// by the instruction, so account for that so it doesn't get
|
|
|
|
// applied twice.
|
|
|
|
Offset = -InstrOffset;
|
|
|
|
|
|
|
|
++NumBaseRegisters;
|
|
|
|
UsedBaseReg = true;
|
2010-08-18 02:13:53 +08:00
|
|
|
}
|
2013-05-01 04:04:37 +08:00
|
|
|
assert(BaseReg != 0 && "Unable to allocate virtual base register!");
|
|
|
|
|
|
|
|
// Modify the instruction to use the new base register rather
|
|
|
|
// than the frame index operand.
|
2016-07-01 07:39:46 +08:00
|
|
|
TRI->resolveFrameIndex(MI, BaseReg, Offset);
|
|
|
|
DEBUG(dbgs() << "Resolved: " << MI);
|
2013-05-01 04:04:37 +08:00
|
|
|
|
|
|
|
++NumReplacements;
|
2010-08-18 02:13:53 +08:00
|
|
|
}
|
2013-05-01 04:04:37 +08:00
|
|
|
|
2010-08-21 00:48:30 +08:00
|
|
|
return UsedBaseReg;
|
2010-08-18 02:13:53 +08:00
|
|
|
}
|