llvm/llvm/lib/CodeGen/StackMapLivenessAnalysis.cpp

//===-- StackMapLivenessAnalysis.cpp - StackMap live Out Analysis ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// 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/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

usingnamespacellvm;

#define DEBUG_TYPE …

static 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");

namespace {
/// This pass calculates the liveness information for each basic block in
/// a function and attaches the register live-out information to a patchpoint
/// intrinsic if present.
///
/// This pass can be disabled via the -enable-patchpoint-liveness=false flag.
/// The pass skips functions that don't have any patchpoint intrinsics. The
/// information provided by this pass is optional and not required by the
/// aformentioned intrinsic to function.
class StackMapLiveness : public MachineFunctionPass { … };
} // namespace

char StackMapLiveness::ID = …;
char &llvm::StackMapLivenessID = …;
INITIALIZE_PASS(…)

/// Default construct and initialize the pass.
StackMapLiveness::StackMapLiveness() : … { … }

/// Tell the pass manager which passes we depend on and what information we
/// preserve.
void StackMapLiveness::getAnalysisUsage(AnalysisUsage &AU) const { … }

/// Calculate the liveness information for the given machine function.
bool StackMapLiveness::runOnMachineFunction(MachineFunction &MF) { … }

/// Performs the actual liveness calculation for the function.
bool StackMapLiveness::calculateLiveness(MachineFunction &MF) { … }

/// Add the current register live set to the instruction.
void StackMapLiveness::addLiveOutSetToMI(MachineFunction &MF,
                                         MachineInstr &MI) { … }

/// Create a register mask and initialize it with the registers from the
/// register live set.
uint32_t *StackMapLiveness::createRegisterMask(MachineFunction &MF) const { … }