llvm/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp

//===-- AArch64Arm64ECCallLowering.cpp - Lower Arm64EC calls ----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains the IR transform to lower external or indirect calls for
/// the ARM64EC calling convention. Such calls must go through the runtime, so
/// we can translate the calling convention for calls into the emulator.
///
/// This subsumes Control Flow Guard handling.
///
//===----------------------------------------------------------------------===//

#include "AArch64.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/InitializePasses.h"
#include "llvm/Object/COFF.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/TargetParser/Triple.h"

usingnamespacellvm;
usingnamespacellvm::COFF;

OperandBundleDef;

#define DEBUG_TYPE …

STATISTIC(Arm64ECCallsLowered, "Number of Arm64EC calls lowered");

static cl::opt<bool> LowerDirectToIndirect("arm64ec-lower-direct-to-indirect",
                                           cl::Hidden, cl::init(true));
static cl::opt<bool> GenerateThunks("arm64ec-generate-thunks", cl::Hidden,
                                    cl::init(true));

namespace {

enum ThunkArgTranslation : uint8_t { … };

struct ThunkArgInfo { … };

class AArch64Arm64ECCallLowering : public ModulePass { … };

} // end anonymous namespace

void AArch64Arm64ECCallLowering::getThunkType(
    FunctionType *FT, AttributeList AttrList, Arm64ECThunkType TT,
    raw_ostream &Out, FunctionType *&Arm64Ty, FunctionType *&X64Ty,
    SmallVector<ThunkArgTranslation> &ArgTranslations) { … }

void AArch64Arm64ECCallLowering::getThunkArgTypes(
    FunctionType *FT, AttributeList AttrList, Arm64ECThunkType TT,
    raw_ostream &Out, SmallVectorImpl<Type *> &Arm64ArgTypes,
    SmallVectorImpl<Type *> &X64ArgTypes,
    SmallVectorImpl<ThunkArgTranslation> &ArgTranslations, bool HasSretPtr) { … }

void AArch64Arm64ECCallLowering::getThunkRetType(
    FunctionType *FT, AttributeList AttrList, raw_ostream &Out,
    Type *&Arm64RetTy, Type *&X64RetTy, SmallVectorImpl<Type *> &Arm64ArgTypes,
    SmallVectorImpl<Type *> &X64ArgTypes,
    SmallVector<ThunkArgTranslation> &ArgTranslations, bool &HasSretPtr) { … }

ThunkArgInfo AArch64Arm64ECCallLowering::canonicalizeThunkType(
    Type *T, Align Alignment, bool Ret, uint64_t ArgSizeBytes,
    raw_ostream &Out) { … }

// This function builds the "exit thunk", a function which translates
// arguments and return values when calling x64 code from AArch64 code.
Function *AArch64Arm64ECCallLowering::buildExitThunk(FunctionType *FT,
                                                     AttributeList Attrs) { … }

// This function builds the "entry thunk", a function which translates
// arguments and return values when calling AArch64 code from x64 code.
Function *AArch64Arm64ECCallLowering::buildEntryThunk(Function *F) { … }

// Builds the "guest exit thunk", a helper to call a function which may or may
// not be an exit thunk. (We optimistically assume non-dllimport function
// declarations refer to functions defined in AArch64 code; if the linker
// can't prove that, we use this routine instead.)
Function *AArch64Arm64ECCallLowering::buildGuestExitThunk(Function *F) { … }

Function *
AArch64Arm64ECCallLowering::buildPatchableThunk(GlobalAlias *UnmangledAlias,
                                                GlobalAlias *MangledAlias) { … }

// Lower an indirect call with inline code.
void AArch64Arm64ECCallLowering::lowerCall(CallBase *CB) { … }

bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) { … }

bool AArch64Arm64ECCallLowering::processFunction(
    Function &F, SetVector<GlobalValue *> &DirectCalledFns,
    DenseMap<GlobalAlias *, GlobalAlias *> &FnsMap) { … }

char AArch64Arm64ECCallLowering::ID = …;
INITIALIZE_PASS(…)

ModulePass *llvm::createAArch64Arm64ECCallLoweringPass() { … }