llvm/llvm/lib/Target/AArch64/GISel/AArch64CallLowering.cpp

//===--- AArch64CallLowering.cpp - Call lowering --------------------------===//
//
// 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 implements the lowering of LLVM calls to machine code calls for
/// GlobalISel.
///
//===----------------------------------------------------------------------===//

#include "AArch64CallLowering.h"
#include "AArch64GlobalISelUtils.h"
#include "AArch64ISelLowering.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64RegisterInfo.h"
#include "AArch64Subtarget.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/ObjCARCUtil.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/LowLevelTypeUtils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGenTypes/MachineValueType.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>

#define DEBUG_TYPE …

usingnamespacellvm;
usingnamespaceAArch64GISelUtils;

extern cl::opt<bool> EnableSVEGISel;

AArch64CallLowering::AArch64CallLowering(const AArch64TargetLowering &TLI)
  : … { … }

static void applyStackPassedSmallTypeDAGHack(EVT OrigVT, MVT &ValVT,
                                             MVT &LocVT) { … }

// Account for i1/i8/i16 stack passed value hack
static LLT getStackValueStoreTypeHack(const CCValAssign &VA) { … }

namespace {

struct AArch64IncomingValueAssigner
    : public CallLowering::IncomingValueAssigner { … };

struct AArch64OutgoingValueAssigner
    : public CallLowering::OutgoingValueAssigner { … };

struct IncomingArgHandler : public CallLowering::IncomingValueHandler { … };

struct FormalArgHandler : public IncomingArgHandler { … };

struct CallReturnHandler : public IncomingArgHandler { … };

/// A special return arg handler for "returned" attribute arg calls.
struct ReturnedArgCallReturnHandler : public CallReturnHandler { … };

struct OutgoingArgHandler : public CallLowering::OutgoingValueHandler { … };
} // namespace

static bool doesCalleeRestoreStack(CallingConv::ID CallConv, bool TailCallOpt) { … }

bool AArch64CallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
                                      const Value *Val,
                                      ArrayRef<Register> VRegs,
                                      FunctionLoweringInfo &FLI,
                                      Register SwiftErrorVReg) const { … }

bool AArch64CallLowering::canLowerReturn(MachineFunction &MF,
                                         CallingConv::ID CallConv,
                                         SmallVectorImpl<BaseArgInfo> &Outs,
                                         bool IsVarArg) const { … }

/// Helper function to compute forwarded registers for musttail calls. Computes
/// the forwarded registers, sets MBB liveness, and emits COPY instructions that
/// can be used to save + restore registers later.
static void handleMustTailForwardedRegisters(MachineIRBuilder &MIRBuilder,
                                             CCAssignFn *AssignFn) { … }

bool AArch64CallLowering::fallBackToDAGISel(const MachineFunction &MF) const { … }

void AArch64CallLowering::saveVarArgRegisters(
    MachineIRBuilder &MIRBuilder, CallLowering::IncomingValueHandler &Handler,
    CCState &CCInfo) const { … }

bool AArch64CallLowering::lowerFormalArguments(
    MachineIRBuilder &MIRBuilder, const Function &F,
    ArrayRef<ArrayRef<Register>> VRegs, FunctionLoweringInfo &FLI) const { … }

/// Return true if the calling convention is one that we can guarantee TCO for.
static bool canGuaranteeTCO(CallingConv::ID CC, bool GuaranteeTailCalls) { … }

/// Return true if we might ever do TCO for calls with this calling convention.
static bool mayTailCallThisCC(CallingConv::ID CC) { … }

/// Returns a pair containing the fixed CCAssignFn and the vararg CCAssignFn for
/// CC.
static std::pair<CCAssignFn *, CCAssignFn *>
getAssignFnsForCC(CallingConv::ID CC, const AArch64TargetLowering &TLI) { … }

bool AArch64CallLowering::doCallerAndCalleePassArgsTheSameWay(
    CallLoweringInfo &Info, MachineFunction &MF,
    SmallVectorImpl<ArgInfo> &InArgs) const { … }

bool AArch64CallLowering::areCalleeOutgoingArgsTailCallable(
    CallLoweringInfo &Info, MachineFunction &MF,
    SmallVectorImpl<ArgInfo> &OrigOutArgs) const { … }

bool AArch64CallLowering::isEligibleForTailCallOptimization(
    MachineIRBuilder &MIRBuilder, CallLoweringInfo &Info,
    SmallVectorImpl<ArgInfo> &InArgs,
    SmallVectorImpl<ArgInfo> &OutArgs) const { … }

static unsigned getCallOpcode(const MachineFunction &CallerF, bool IsIndirect,
                              bool IsTailCall,
                              std::optional<CallLowering::PtrAuthInfo> &PAI,
                              MachineRegisterInfo &MRI) { … }

static const uint32_t *
getMaskForArgs(SmallVectorImpl<AArch64CallLowering::ArgInfo> &OutArgs,
               AArch64CallLowering::CallLoweringInfo &Info,
               const AArch64RegisterInfo &TRI, MachineFunction &MF) { … }

bool AArch64CallLowering::lowerTailCall(
    MachineIRBuilder &MIRBuilder, CallLoweringInfo &Info,
    SmallVectorImpl<ArgInfo> &OutArgs) const { … }

bool AArch64CallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
                                    CallLoweringInfo &Info) const { … }

bool AArch64CallLowering::isTypeIsValidForThisReturn(EVT Ty) const { … }