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307a6447e5
There is no need to calculate the liveness information for stackmaps. The liveness information is still available for the patchpoint intrinsic and that is also the intended usage model. Related to <rdar://problem/17473725> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211816 91177308-0d34-0410-b5e6-96231b3b80d8
125 lines
4.5 KiB
C++
125 lines
4.5 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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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::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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DEBUG(dbgs() << "********** COMPUTING STACKMAP LIVENESS: "
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<< _MF.getName() << " **********\n");
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MF = &_MF;
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TRI = MF->getTarget().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() && EnablePatchPointLiveness)) {
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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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int Opc = I->getOpcode();
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if (Opc == 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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