da816c2985
With LLVM patch https://reviews.llvm.org/D148269, we hit a linux kernel bpf selftest compilation failure like below: ... progs/test_xdp_noinline.c:739:8: error: too many args to t8: i64 = GlobalAddress<ptr @encap_v4> 0, progs/test_xdp_noinline.c:739:8 if (!encap_v4(xdp, cval, &pckt, dst, pkt_bytes)) ^ ... progs/test_xdp_noinline.c:321:6: error: defined with too many args bool encap_v4(struct xdp_md *xdp, struct ctl_value *cval, ^ ... Note that bpf selftests are compiled with -O2 which is the recommended flag for bpf community. The bpf backend calling convention is only allowing 5 parameters in registers and does not allow pass arguments through stacks. In the above case, ArgumentPromotionPass replaced parameter '&pckt' as two parameters, so the total number of arguments after ArgumentPromotion pass becomes 6 and this caused later compilation failure during instruction selection phase. This patch added a TargetTransformInfo hook getMaxNumArgs() which returns 5 for BPF and UINT_MAX for other targets. Differential Revision: https://reviews.llvm.org/D148551
89 lines
3.2 KiB
C++
89 lines
3.2 KiB
C++
//===------ BPFTargetTransformInfo.h - BPF specific TTI ---------*- 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 uses the target's specific information to
|
|
// provide more precise answers to certain TTI queries, while letting the
|
|
// target independent and default TTI implementations handle the rest.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_LIB_TARGET_BPF_BPFTARGETTRANSFORMINFO_H
|
|
#define LLVM_LIB_TARGET_BPF_BPFTARGETTRANSFORMINFO_H
|
|
|
|
#include "BPFTargetMachine.h"
|
|
#include "llvm/Analysis/TargetTransformInfo.h"
|
|
#include "llvm/CodeGen/BasicTTIImpl.h"
|
|
#include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
|
|
|
|
namespace llvm {
|
|
class BPFTTIImpl : public BasicTTIImplBase<BPFTTIImpl> {
|
|
typedef BasicTTIImplBase<BPFTTIImpl> BaseT;
|
|
typedef TargetTransformInfo TTI;
|
|
friend BaseT;
|
|
|
|
const BPFSubtarget *ST;
|
|
const BPFTargetLowering *TLI;
|
|
|
|
const BPFSubtarget *getST() const { return ST; }
|
|
const BPFTargetLowering *getTLI() const { return TLI; }
|
|
|
|
public:
|
|
explicit BPFTTIImpl(const BPFTargetMachine *TM, const Function &F)
|
|
: BaseT(TM, F.getParent()->getDataLayout()), ST(TM->getSubtargetImpl(F)),
|
|
TLI(ST->getTargetLowering()) {}
|
|
|
|
int getIntImmCost(const APInt &Imm, Type *Ty, TTI::TargetCostKind CostKind) {
|
|
if (Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
|
|
return TTI::TCC_Free;
|
|
|
|
return TTI::TCC_Basic;
|
|
}
|
|
|
|
InstructionCost getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
|
|
CmpInst::Predicate VecPred,
|
|
TTI::TargetCostKind CostKind,
|
|
const llvm::Instruction *I = nullptr) {
|
|
if (Opcode == Instruction::Select)
|
|
return SCEVCheapExpansionBudget.getValue();
|
|
|
|
return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
|
|
I);
|
|
}
|
|
|
|
InstructionCost getArithmeticInstrCost(
|
|
unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
|
|
TTI::OperandValueInfo Op1Info = {TTI::OK_AnyValue, TTI::OP_None},
|
|
TTI::OperandValueInfo Op2Info = {TTI::OK_AnyValue, TTI::OP_None},
|
|
ArrayRef<const Value *> Args = ArrayRef<const Value *>(),
|
|
const Instruction *CxtI = nullptr) {
|
|
int ISD = TLI->InstructionOpcodeToISD(Opcode);
|
|
if (ISD == ISD::ADD && CostKind == TTI::TCK_RecipThroughput)
|
|
return SCEVCheapExpansionBudget.getValue() + 1;
|
|
|
|
return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info,
|
|
Op2Info);
|
|
}
|
|
|
|
TTI::MemCmpExpansionOptions enableMemCmpExpansion(bool OptSize,
|
|
bool IsZeroCmp) const {
|
|
TTI::MemCmpExpansionOptions Options;
|
|
Options.LoadSizes = {8, 4, 2, 1};
|
|
Options.MaxNumLoads = TLI->getMaxExpandSizeMemcmp(OptSize);
|
|
return Options;
|
|
}
|
|
|
|
unsigned getMaxNumArgs() const {
|
|
return 5;
|
|
}
|
|
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif // LLVM_LIB_TARGET_BPF_BPFTARGETTRANSFORMINFO_H
|