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author | Andrew Trick <atrick@apple.com> | 2013-12-13 18:37:03 +0000 |
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committer | Andrew Trick <atrick@apple.com> | 2013-12-13 18:37:03 +0000 |
commit | 539e93120cdbb66f651fc55a810416f3175adc8f (patch) | |
tree | e845453b166d6f8b462ef306f7e9b0d7cede2bbf /lib/CodeGen/StackMapLivenessAnalysis.cpp | |
parent | edf1070ca74f7d646bce2c66db9f443d09e7d1d3 (diff) | |
download | llvm-539e93120cdbb66f651fc55a810416f3175adc8f.tar.gz llvm-539e93120cdbb66f651fc55a810416f3175adc8f.tar.bz2 llvm-539e93120cdbb66f651fc55a810416f3175adc8f.tar.xz |
Liveness Analysis Pass
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197254 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/StackMapLivenessAnalysis.cpp')
-rw-r--r-- | lib/CodeGen/StackMapLivenessAnalysis.cpp | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/lib/CodeGen/StackMapLivenessAnalysis.cpp b/lib/CodeGen/StackMapLivenessAnalysis.cpp new file mode 100644 index 0000000000..788b83416b --- /dev/null +++ b/lib/CodeGen/StackMapLivenessAnalysis.cpp @@ -0,0 +1,128 @@ +//===-- StackMapLivenessAnalysis.cpp - StackMap live Out Analysis ----------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the StackMap Liveness analysis pass. The pass calculates +// the liveness for each basic block in a function and attaches the register +// live-out information to a stackmap or patchpoint intrinsic if present. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "stackmaps" +#include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFunctionAnalysis.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/CodeGen/StackMapLivenessAnalysis.h" +#include "llvm/Support/Debug.h" + +using namespace llvm; + + +STATISTIC(NumStackMapFuncVisited, "Number of functions visited"); +STATISTIC(NumStackMapFuncSkipped, "Number of functions skipped"); +STATISTIC(NumBBsVisited, "Number of basic blocks visited"); +STATISTIC(NumBBsHaveNoStackmap, "Number of basic blocks with no stackmap"); +STATISTIC(NumStackMaps, "Number of StackMaps visited"); + +char StackMapLiveness::ID = 0; +char &llvm::StackMapLivenessID = StackMapLiveness::ID; +INITIALIZE_PASS(StackMapLiveness, "stackmap-liveness", + "StackMap Liveness Analysis", false, false) + +/// Default construct and initialize the pass. +StackMapLiveness::StackMapLiveness() : MachineFunctionPass(ID) { + initializeStackMapLivenessPass(*PassRegistry::getPassRegistry()); +} + +/// Tell the pass manager which passes we depend on and what information we +/// preserve. +void StackMapLiveness::getAnalysisUsage(AnalysisUsage &AU) const { + // We preserve all information. + AU.setPreservesAll(); + AU.setPreservesCFG(); + // Default dependencie for all MachineFunction passes. + AU.addRequired<MachineFunctionAnalysis>(); +} + +/// Calculate the liveness information for the given machine function. +bool StackMapLiveness::runOnMachineFunction(MachineFunction &_MF) { + DEBUG(dbgs() << "********** COMPUTING STACKMAP LIVENESS: " + << _MF.getName() << " **********\n"); + MF = &_MF; + TRI = MF->getTarget().getRegisterInfo(); + ++NumStackMapFuncVisited; + + // Skip this function if there are no stackmaps. + if (!MF->getFrameInfo()->hasStackMap()) { + ++NumStackMapFuncSkipped; + return false; + } + return calculateLiveness(); +} + +/// Performs the actual liveness calculation for the function. +bool StackMapLiveness::calculateLiveness() { + bool HasChanged = false; + // For all basic blocks in the function. + for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end(); + MBBI != MBBE; ++MBBI) { + DEBUG(dbgs() << "****** BB " << MBBI->getName() << " ******\n"); + LiveRegs.init(TRI); + LiveRegs.addLiveOuts(MBBI); + bool HasStackMap = false; + // Reverse iterate over all instructions and add the current live register + // set to an instruction if we encounter a stackmap or patchpoint + // instruction. + for (MachineBasicBlock::reverse_iterator I = MBBI->rbegin(), + E = MBBI->rend(); I != E; ++I) { + if (I->getOpcode() == TargetOpcode::STACKMAP || + I->getOpcode() == TargetOpcode::PATCHPOINT) { + addLiveOutSetToMI(*I); + HasChanged = true; + HasStackMap = true; + ++NumStackMaps; + } + LiveRegs.stepBackward(*I); + } + ++NumBBsVisited; + if (!HasStackMap) + ++NumBBsHaveNoStackmap; + } + return HasChanged; +} + +/// Add the current register live set to the instruction. +void StackMapLiveness::addLiveOutSetToMI(MachineInstr &MI) { + uint32_t *Mask = createRegisterMask(); + MachineOperand MO = MachineOperand::CreateRegLiveOut(Mask); + MI.addOperand(*MF, MO); + DEBUG(dbgs() << " " << MI); + DEBUG(printLiveOutSet(dbgs())); +} + +/// Create a register mask and initialize it with the registers from the +/// register live set. +uint32_t *StackMapLiveness::createRegisterMask() const { + // The mask is owned and cleaned up by the Machine Function. + uint32_t *Mask = MF->allocateRegisterMask(TRI->getNumRegs()); + for (LivePhysRegs::const_iterator RI = LiveRegs.begin(), RE = LiveRegs.end(); + RI != RE; ++RI) + Mask[*RI / 32] |= 1U << (*RI % 32); + return Mask; +} + +/// Print the current register live set for debugging. +void StackMapLiveness::printLiveOutSet(raw_ostream &OS) const { + OS << " Register live-out:"; + for (LivePhysRegs::const_iterator RI = LiveRegs.begin(), RE = LiveRegs.end(); + RI != RE; ++RI) + OS << " " << TRI->getName(*RI); + OS << "\n"; +} |