llvm-mirror/lib/CodeGen/StackMapLivenessAnalysis.cpp
Eric Christopher 67c04e77e5 Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

llvm-svn: 214838
2014-08-05 02:39:49 +00:00

128 lines
4.6 KiB
C++

//===-- 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.
//
//===----------------------------------------------------------------------===//
#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/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
#define DEBUG_TYPE "stackmaps"
namespace llvm {
cl::opt<bool> EnablePatchPointLiveness("enable-patchpoint-liveness",
cl::Hidden, cl::init(true),
cl::desc("Enable PatchPoint Liveness Analysis Pass"));
}
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) {
if (!EnablePatchPointLiveness)
return false;
DEBUG(dbgs() << "********** COMPUTING STACKMAP LIVENESS: "
<< _MF.getName() << " **********\n");
MF = &_MF;
TRI = MF->getSubtarget().getRegisterInfo();
++NumStackMapFuncVisited;
// Skip this function if there are no patchpoints to process.
if (!MF->getFrameInfo()->hasPatchPoint()) {
++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 patchpoint instruction.
for (MachineBasicBlock::reverse_iterator I = MBBI->rbegin(),
E = MBBI->rend(); I != E; ++I) {
if (I->getOpcode() == TargetOpcode::PATCHPOINT) {
addLiveOutSetToMI(*I);
HasChanged = true;
HasStackMap = true;
++NumStackMaps;
}
DEBUG(dbgs() << " " << LiveRegs << " " << *I);
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);
}
/// 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;
}