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llvm-project/llvm/lib/Target/AArch64/AArch64CallingConvention.cpp

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//=== AArch64CallingConvention.cpp - AArch64 CC impl ------------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file contains the table-generated and custom routines for the AArch64
// Calling Convention.
//
//===----------------------------------------------------------------------===//
#include "AArch64CallingConvention.h"
#include "AArch64.h"
#include "AArch64InstrInfo.h"
#include "AArch64Subtarget.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/IR/CallingConv.h"
using namespace llvm;
static const MCPhysReg XRegList[] = {AArch64::X0, AArch64::X1, AArch64::X2,
AArch64::X3, AArch64::X4, AArch64::X5,
AArch64::X6, AArch64::X7};
static const MCPhysReg HRegList[] = {AArch64::H0, AArch64::H1, AArch64::H2,
AArch64::H3, AArch64::H4, AArch64::H5,
AArch64::H6, AArch64::H7};
static const MCPhysReg SRegList[] = {AArch64::S0, AArch64::S1, AArch64::S2,
AArch64::S3, AArch64::S4, AArch64::S5,
AArch64::S6, AArch64::S7};
static const MCPhysReg DRegList[] = {AArch64::D0, AArch64::D1, AArch64::D2,
AArch64::D3, AArch64::D4, AArch64::D5,
AArch64::D6, AArch64::D7};
static const MCPhysReg QRegList[] = {AArch64::Q0, AArch64::Q1, AArch64::Q2,
AArch64::Q3, AArch64::Q4, AArch64::Q5,
AArch64::Q6, AArch64::Q7};
static const MCPhysReg ZRegList[] = {AArch64::Z0, AArch64::Z1, AArch64::Z2,
AArch64::Z3, AArch64::Z4, AArch64::Z5,
AArch64::Z6, AArch64::Z7};
static bool finishStackBlock(SmallVectorImpl<CCValAssign> &PendingMembers,
MVT LocVT, ISD::ArgFlagsTy &ArgFlags,
CCState &State, Align SlotAlign) {
if (LocVT.isScalableVector()) {
const AArch64Subtarget &Subtarget = static_cast<const AArch64Subtarget &>(
State.getMachineFunction().getSubtarget());
const AArch64TargetLowering *TLI = Subtarget.getTargetLowering();
// We are about to reinvoke the CCAssignFn auto-generated handler. If we
// don't unset these flags we will get stuck in an infinite loop forever
// invoking the custom handler.
ArgFlags.setInConsecutiveRegs(false);
ArgFlags.setInConsecutiveRegsLast(false);
// The calling convention for passing SVE tuples states that in the event
// we cannot allocate enough registers for the tuple we should still leave
// any remaining registers unallocated. However, when we call the
// CCAssignFn again we want it to behave as if all remaining registers are
// allocated. This will force the code to pass the tuple indirectly in
// accordance with the PCS.
bool RegsAllocated[8];
for (int I = 0; I < 8; I++) {
RegsAllocated[I] = State.isAllocated(ZRegList[I]);
State.AllocateReg(ZRegList[I]);
}
auto &It = PendingMembers[0];
CCAssignFn *AssignFn =
TLI->CCAssignFnForCall(State.getCallingConv(), /*IsVarArg=*/false);
if (AssignFn(It.getValNo(), It.getValVT(), It.getValVT(), CCValAssign::Full,
ArgFlags, State))
llvm_unreachable("Call operand has unhandled type");
// Return the flags to how they were before.
ArgFlags.setInConsecutiveRegs(true);
ArgFlags.setInConsecutiveRegsLast(true);
// Return the register state back to how it was before, leaving any
// unallocated registers available for other smaller types.
for (int I = 0; I < 8; I++)
if (!RegsAllocated[I])
State.DeallocateReg(ZRegList[I]);
// All pending members have now been allocated
PendingMembers.clear();
return true;
}
unsigned Size = LocVT.getSizeInBits() / 8;
const Align StackAlign =
State.getMachineFunction().getDataLayout().getStackAlignment();
const Align OrigAlign = ArgFlags.getNonZeroOrigAlign();
const Align Alignment = std::min(OrigAlign, StackAlign);
for (auto &It : PendingMembers) {
It.convertToMem(State.AllocateStack(Size, std::max(Alignment, SlotAlign)));
State.addLoc(It);
SlotAlign = Align(1);
}
// All pending members have now been allocated
PendingMembers.clear();
return true;
}
/// The Darwin variadic PCS places anonymous arguments in 8-byte stack slots. An
/// [N x Ty] type must still be contiguous in memory though.
static bool CC_AArch64_Custom_Stack_Block(
unsigned &ValNo, MVT &ValVT, MVT &LocVT, CCValAssign::LocInfo &LocInfo,
ISD::ArgFlagsTy &ArgFlags, CCState &State) {
SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
// Add the argument to the list to be allocated once we know the size of the
// block.
PendingMembers.push_back(
CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo));
if (!ArgFlags.isInConsecutiveRegsLast())
return true;
return finishStackBlock(PendingMembers, LocVT, ArgFlags, State, Align(8));
}
/// Given an [N x Ty] block, it should be passed in a consecutive sequence of
/// registers. If no such sequence is available, mark the rest of the registers
/// of that type as used and place the argument on the stack.
static bool CC_AArch64_Custom_Block(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
CCValAssign::LocInfo &LocInfo,
ISD::ArgFlagsTy &ArgFlags, CCState &State) {
const AArch64Subtarget &Subtarget = static_cast<const AArch64Subtarget &>(
State.getMachineFunction().getSubtarget());
bool IsDarwinILP32 = Subtarget.isTargetILP32() && Subtarget.isTargetMachO();
// Try to allocate a contiguous block of registers, each of the correct
// size to hold one member.
ArrayRef<MCPhysReg> RegList;
if (LocVT.SimpleTy == MVT::i64 || (IsDarwinILP32 && LocVT.SimpleTy == MVT::i32))
RegList = XRegList;
else if (LocVT.SimpleTy == MVT::f16)
RegList = HRegList;
else if (LocVT.SimpleTy == MVT::f32 || LocVT.is32BitVector())
RegList = SRegList;
else if (LocVT.SimpleTy == MVT::f64 || LocVT.is64BitVector())
RegList = DRegList;
else if (LocVT.SimpleTy == MVT::f128 || LocVT.is128BitVector())
RegList = QRegList;
else if (LocVT.isScalableVector())
RegList = ZRegList;
else {
// Not an array we want to split up after all.
return false;
}
SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
// Add the argument to the list to be allocated once we know the size of the
// block.
PendingMembers.push_back(
CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo));
if (!ArgFlags.isInConsecutiveRegsLast())
return true;
// [N x i32] arguments get packed into x-registers on Darwin's arm64_32
// because that's how the armv7k Clang front-end emits small structs.
unsigned EltsPerReg = (IsDarwinILP32 && LocVT.SimpleTy == MVT::i32) ? 2 : 1;
unsigned RegResult = State.AllocateRegBlock(
RegList, alignTo(PendingMembers.size(), EltsPerReg) / EltsPerReg);
if (RegResult && EltsPerReg == 1) {
for (auto &It : PendingMembers) {
It.convertToReg(RegResult);
State.addLoc(It);
++RegResult;
}
PendingMembers.clear();
return true;
} else if (RegResult) {
assert(EltsPerReg == 2 && "unexpected ABI");
bool UseHigh = false;
CCValAssign::LocInfo Info;
for (auto &It : PendingMembers) {
Info = UseHigh ? CCValAssign::AExtUpper : CCValAssign::ZExt;
State.addLoc(CCValAssign::getReg(It.getValNo(), MVT::i32, RegResult,
MVT::i64, Info));
UseHigh = !UseHigh;
if (!UseHigh)
++RegResult;
}
PendingMembers.clear();
return true;
}
if (!LocVT.isScalableVector()) {
// Mark all regs in the class as unavailable
for (auto Reg : RegList)
State.AllocateReg(Reg);
}
const Align SlotAlign = Subtarget.isTargetDarwin() ? Align(1) : Align(8);
return finishStackBlock(PendingMembers, LocVT, ArgFlags, State, SlotAlign);
}
// TableGen provides definitions of the calling convention analysis entry
// points.
#include "AArch64GenCallingConv.inc"
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