llvm/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp

//===- PreISelIntrinsicLowering.cpp - Pre-ISel intrinsic lowering pass ----===//
//
// 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 pass implements IR lowering for the llvm.memcpy, llvm.memmove,
// llvm.memset, llvm.load.relative and llvm.objc.* intrinsics.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/PreISelIntrinsicLowering.h"
#include "llvm/Analysis/ObjCARCInstKind.h"
#include "llvm/Analysis/ObjCARCUtil.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/ExpandVectorPredication.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Scalar/LowerConstantIntrinsics.h"
#include "llvm/Transforms/Utils/LowerMemIntrinsics.h"

usingnamespacellvm;

/// Threshold to leave statically sized memory intrinsic calls. Calls of known
/// size larger than this will be expanded by the pass. Calls of unknown or
/// lower size will be left for expansion in codegen.
static cl::opt<int64_t> MemIntrinsicExpandSizeThresholdOpt(
    "mem-intrinsic-expand-size",
    cl::desc("Set minimum mem intrinsic size to expand in IR"), cl::init(-1),
    cl::Hidden);

namespace {

struct PreISelIntrinsicLowering { … };

} // namespace

template <class T> static bool forEachCall(Function &Intrin, T Callback) { … }

static bool lowerLoadRelative(Function &F) { … }

// ObjCARC has knowledge about whether an obj-c runtime function needs to be
// always tail-called or never tail-called.
static CallInst::TailCallKind getOverridingTailCallKind(const Function &F) { … }

static bool lowerObjCCall(Function &F, const char *NewFn,
                          bool setNonLazyBind = false) { … }

// TODO: Should refine based on estimated number of accesses (e.g. does it
// require splitting based on alignment)
bool PreISelIntrinsicLowering::shouldExpandMemIntrinsicWithSize(
    Value *Size, const TargetTransformInfo &TTI) { … }

static bool canEmitLibcall(const TargetMachine *TM, Function *F,
                           RTLIB::Libcall LC) { … }

// TODO: Handle atomic memcpy and memcpy.inline
// TODO: Pass ScalarEvolution
bool PreISelIntrinsicLowering::expandMemIntrinsicUses(Function &F) const { … }

bool PreISelIntrinsicLowering::lowerIntrinsics(Module &M) const { … }

namespace {

class PreISelIntrinsicLoweringLegacyPass : public ModulePass { … };

} // end anonymous namespace

char PreISelIntrinsicLoweringLegacyPass::ID;

INITIALIZE_PASS_BEGIN(PreISelIntrinsicLoweringLegacyPass,
                      "pre-isel-intrinsic-lowering",
                      "Pre-ISel Intrinsic Lowering", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_END(PreISelIntrinsicLoweringLegacyPass,
                    "pre-isel-intrinsic-lowering",
                    "Pre-ISel Intrinsic Lowering", false, false)

ModulePass *llvm::createPreISelIntrinsicLoweringPass() { … }

PreservedAnalyses PreISelIntrinsicLoweringPass::run(Module &M,
                                                    ModuleAnalysisManager &AM) { … }