143 lines
4.9 KiB
C++
143 lines
4.9 KiB
C++
//===-- RegUsageInfoCollector.cpp - Register Usage Information Collector --===//
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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 is required to take advantage of the interprocedural register
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/// allocation infrastructure.
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///
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/// This pass is simple MachineFunction pass which collects register usage
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/// details by iterating through each physical registers and checking
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/// MRI::isPhysRegUsed() then creates a RegMask based on this details.
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/// The pass then stores this RegMask in PhysicalRegisterUsageInfo.cpp
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///
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineOperand.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/RegisterUsageInfo.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetFrameLowering.h"
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using namespace llvm;
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#define DEBUG_TYPE "ip-regalloc"
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STATISTIC(NumCSROpt,
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"Number of functions optimized for callee saved registers");
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namespace llvm {
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void initializeRegUsageInfoCollectorPass(PassRegistry &);
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}
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namespace {
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class RegUsageInfoCollector : public MachineFunctionPass {
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public:
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RegUsageInfoCollector() : MachineFunctionPass(ID) {
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PassRegistry &Registry = *PassRegistry::getPassRegistry();
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initializeRegUsageInfoCollectorPass(Registry);
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}
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const char *getPassName() const override {
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return "Register Usage Information Collector Pass";
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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bool runOnMachineFunction(MachineFunction &MF) override;
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static char ID;
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private:
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void markRegClobbered(const TargetRegisterInfo *TRI, uint32_t *RegMask,
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unsigned PReg);
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};
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} // end of anonymous namespace
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char RegUsageInfoCollector::ID = 0;
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INITIALIZE_PASS_BEGIN(RegUsageInfoCollector, "RegUsageInfoCollector",
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"Register Usage Information Collector", false, false)
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INITIALIZE_PASS_DEPENDENCY(PhysicalRegisterUsageInfo)
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INITIALIZE_PASS_END(RegUsageInfoCollector, "RegUsageInfoCollector",
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"Register Usage Information Collector", false, false)
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FunctionPass *llvm::createRegUsageInfoCollector() {
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return new RegUsageInfoCollector();
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}
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void RegUsageInfoCollector::markRegClobbered(const TargetRegisterInfo *TRI,
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uint32_t *RegMask, unsigned PReg) {
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// If PReg is clobbered then all of its alias are also clobbered.
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for (MCRegAliasIterator AI(PReg, TRI, true); AI.isValid(); ++AI)
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RegMask[*AI / 32] &= ~(1u << *AI % 32);
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}
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void RegUsageInfoCollector::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<PhysicalRegisterUsageInfo>();
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AU.setPreservesAll();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool RegUsageInfoCollector::runOnMachineFunction(MachineFunction &MF) {
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MachineRegisterInfo *MRI = &MF.getRegInfo();
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const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
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const TargetMachine &TM = MF.getTarget();
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DEBUG(dbgs() << " -------------------- " << getPassName()
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<< " -------------------- \n");
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DEBUG(dbgs() << "Function Name : " << MF.getName() << "\n");
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std::vector<uint32_t> RegMask;
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// Compute the size of the bit vector to represent all the registers.
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// The bit vector is broken into 32-bit chunks, thus takes the ceil of
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// the number of registers divided by 32 for the size.
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unsigned RegMaskSize = (TRI->getNumRegs() + 31) / 32;
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RegMask.resize(RegMaskSize, 0xFFFFFFFF);
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const Function *F = MF.getFunction();
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PhysicalRegisterUsageInfo *PRUI = &getAnalysis<PhysicalRegisterUsageInfo>();
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PRUI->setTargetMachine(&TM);
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DEBUG(dbgs() << "Clobbered Registers: ");
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for (unsigned PReg = 1, PRegE = TRI->getNumRegs(); PReg < PRegE; ++PReg)
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if (MRI->isPhysRegModified(PReg, true))
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markRegClobbered(TRI, &RegMask[0], PReg);
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if (!TargetFrameLowering::isSafeForNoCSROpt(F)) {
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const uint32_t *CallPreservedMask =
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TRI->getCallPreservedMask(MF, F->getCallingConv());
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// Set callee saved register as preserved.
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for (unsigned i = 0; i < RegMaskSize; ++i)
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RegMask[i] = RegMask[i] | CallPreservedMask[i];
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} else {
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++NumCSROpt;
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DEBUG(dbgs() << MF.getName()
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<< " function optimized for not having CSR.\n");
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}
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for (unsigned PReg = 1, PRegE = TRI->getNumRegs(); PReg < PRegE; ++PReg)
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if (MachineOperand::clobbersPhysReg(&(RegMask[0]), PReg))
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DEBUG(dbgs() << TRI->getName(PReg) << " ");
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DEBUG(dbgs() << " \n----------------------------------------\n");
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PRUI->storeUpdateRegUsageInfo(F, std::move(RegMask));
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return false;
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}
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