128 lines
4.6 KiB
C++
128 lines
4.6 KiB
C++
//===-- StackMapLivenessAnalysis.cpp - StackMap live Out Analysis ----------===//
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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 file implements the StackMap Liveness analysis pass. The pass calculates
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// the liveness for each basic block in a function and attaches the register
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// live-out information to a stackmap or patchpoint intrinsic if present.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/Statistic.h"
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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/MachineFunctionAnalysis.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/StackMapLivenessAnalysis.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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using namespace llvm;
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#define DEBUG_TYPE "stackmaps"
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namespace llvm {
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cl::opt<bool> EnablePatchPointLiveness("enable-patchpoint-liveness",
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cl::Hidden, cl::init(true),
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cl::desc("Enable PatchPoint Liveness Analysis Pass"));
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}
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STATISTIC(NumStackMapFuncVisited, "Number of functions visited");
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STATISTIC(NumStackMapFuncSkipped, "Number of functions skipped");
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STATISTIC(NumBBsVisited, "Number of basic blocks visited");
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STATISTIC(NumBBsHaveNoStackmap, "Number of basic blocks with no stackmap");
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STATISTIC(NumStackMaps, "Number of StackMaps visited");
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char StackMapLiveness::ID = 0;
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char &llvm::StackMapLivenessID = StackMapLiveness::ID;
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INITIALIZE_PASS(StackMapLiveness, "stackmap-liveness",
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"StackMap Liveness Analysis", false, false)
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/// Default construct and initialize the pass.
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StackMapLiveness::StackMapLiveness() : MachineFunctionPass(ID) {
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initializeStackMapLivenessPass(*PassRegistry::getPassRegistry());
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}
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/// Tell the pass manager which passes we depend on and what information we
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/// preserve.
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void StackMapLiveness::getAnalysisUsage(AnalysisUsage &AU) const {
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// We preserve all information.
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AU.setPreservesAll();
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AU.setPreservesCFG();
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// Default dependencie for all MachineFunction passes.
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AU.addRequired<MachineFunctionAnalysis>();
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}
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/// Calculate the liveness information for the given machine function.
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bool StackMapLiveness::runOnMachineFunction(MachineFunction &_MF) {
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if (!EnablePatchPointLiveness)
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return false;
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DEBUG(dbgs() << "********** COMPUTING STACKMAP LIVENESS: "
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<< _MF.getName() << " **********\n");
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MF = &_MF;
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TRI = MF->getSubtarget().getRegisterInfo();
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++NumStackMapFuncVisited;
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// Skip this function if there are no patchpoints to process.
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if (!MF->getFrameInfo()->hasPatchPoint()) {
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++NumStackMapFuncSkipped;
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return false;
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}
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return calculateLiveness();
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}
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/// Performs the actual liveness calculation for the function.
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bool StackMapLiveness::calculateLiveness() {
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bool HasChanged = false;
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// For all basic blocks in the function.
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for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
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MBBI != MBBE; ++MBBI) {
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DEBUG(dbgs() << "****** BB " << MBBI->getName() << " ******\n");
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LiveRegs.init(TRI);
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LiveRegs.addLiveOuts(MBBI);
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bool HasStackMap = false;
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// Reverse iterate over all instructions and add the current live register
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// set to an instruction if we encounter a patchpoint instruction.
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for (MachineBasicBlock::reverse_iterator I = MBBI->rbegin(),
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E = MBBI->rend(); I != E; ++I) {
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if (I->getOpcode() == TargetOpcode::PATCHPOINT) {
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addLiveOutSetToMI(*I);
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HasChanged = true;
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HasStackMap = true;
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++NumStackMaps;
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}
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DEBUG(dbgs() << " " << LiveRegs << " " << *I);
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LiveRegs.stepBackward(*I);
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}
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++NumBBsVisited;
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if (!HasStackMap)
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++NumBBsHaveNoStackmap;
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}
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return HasChanged;
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}
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/// Add the current register live set to the instruction.
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void StackMapLiveness::addLiveOutSetToMI(MachineInstr &MI) {
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uint32_t *Mask = createRegisterMask();
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MachineOperand MO = MachineOperand::CreateRegLiveOut(Mask);
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MI.addOperand(*MF, MO);
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}
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/// Create a register mask and initialize it with the registers from the
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/// register live set.
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uint32_t *StackMapLiveness::createRegisterMask() const {
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// The mask is owned and cleaned up by the Machine Function.
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uint32_t *Mask = MF->allocateRegisterMask(TRI->getNumRegs());
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for (LivePhysRegs::const_iterator RI = LiveRegs.begin(), RE = LiveRegs.end();
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RI != RE; ++RI)
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Mask[*RI / 32] |= 1U << (*RI % 32);
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return Mask;
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}
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