llvm-project/llvm/lib/IR/PseudoProbe.cpp
Hongtao Yu 40508e3ed9 [PseudoProbe] Remove unnecessary asserts about non-zero discriminator.
Despite previous efforts in fixing accidentally setting deduplication factor and avoiding enforcing a callsite debug loc for pseudo probes, I'm still seeing an IR probe having a non-zero discriminator. This time it is due to the merge of two probes with irreconsilable debug locations and the merged probe ends up getting the original callsite locs. Therefore I'm removing the assert about IR probe should always have a zero discriminator. This safe since
- Probe discriminators are only emitted in FS-AFDO mode; and
- The first FS discriminator assigning pass always clears non-discriminators left over from IR passes.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D155252
2023-07-17 09:43:10 -07:00

113 lines
4.0 KiB
C++

//===- PseudoProbe.cpp - Pseudo Probe Helpers -----------------------------===//
//
// 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 implements the helpers to manipulate pseudo probe IR intrinsic
// calls.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/PseudoProbe.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
using namespace llvm;
namespace llvm {
std::optional<PseudoProbe>
extractProbeFromDiscriminator(const DILocation *DIL) {
if (DIL) {
auto Discriminator = DIL->getDiscriminator();
if (DILocation::isPseudoProbeDiscriminator(Discriminator)) {
PseudoProbe Probe;
Probe.Id =
PseudoProbeDwarfDiscriminator::extractProbeIndex(Discriminator);
Probe.Type =
PseudoProbeDwarfDiscriminator::extractProbeType(Discriminator);
Probe.Attr =
PseudoProbeDwarfDiscriminator::extractProbeAttributes(Discriminator);
Probe.Factor =
PseudoProbeDwarfDiscriminator::extractProbeFactor(Discriminator) /
(float)PseudoProbeDwarfDiscriminator::FullDistributionFactor;
Probe.Discriminator = 0;
return Probe;
}
}
return std::nullopt;
}
std::optional<PseudoProbe>
extractProbeFromDiscriminator(const Instruction &Inst) {
assert(isa<CallBase>(&Inst) && !isa<IntrinsicInst>(&Inst) &&
"Only call instructions should have pseudo probe encodes as their "
"Dwarf discriminators");
if (const DebugLoc &DLoc = Inst.getDebugLoc())
return extractProbeFromDiscriminator(DLoc);
return std::nullopt;
}
std::optional<PseudoProbe> extractProbe(const Instruction &Inst) {
if (const auto *II = dyn_cast<PseudoProbeInst>(&Inst)) {
PseudoProbe Probe;
Probe.Id = II->getIndex()->getZExtValue();
Probe.Type = (uint32_t)PseudoProbeType::Block;
Probe.Attr = II->getAttributes()->getZExtValue();
Probe.Factor = II->getFactor()->getZExtValue() /
(float)PseudoProbeFullDistributionFactor;
Probe.Discriminator = 0;
if (const DebugLoc &DLoc = Inst.getDebugLoc())
Probe.Discriminator = DLoc->getDiscriminator();
return Probe;
}
if (isa<CallBase>(&Inst) && !isa<IntrinsicInst>(&Inst))
return extractProbeFromDiscriminator(Inst);
return std::nullopt;
}
void setProbeDistributionFactor(Instruction &Inst, float Factor) {
assert(Factor >= 0 && Factor <= 1 &&
"Distribution factor must be in [0, 1.0]");
if (auto *II = dyn_cast<PseudoProbeInst>(&Inst)) {
IRBuilder<> Builder(&Inst);
uint64_t IntFactor = PseudoProbeFullDistributionFactor;
if (Factor < 1)
IntFactor *= Factor;
auto OrigFactor = II->getFactor()->getZExtValue();
if (IntFactor != OrigFactor)
II->replaceUsesOfWith(II->getFactor(), Builder.getInt64(IntFactor));
} else if (isa<CallBase>(&Inst) && !isa<IntrinsicInst>(&Inst)) {
if (const DebugLoc &DLoc = Inst.getDebugLoc()) {
const DILocation *DIL = DLoc;
auto Discriminator = DIL->getDiscriminator();
if (DILocation::isPseudoProbeDiscriminator(Discriminator)) {
auto Index =
PseudoProbeDwarfDiscriminator::extractProbeIndex(Discriminator);
auto Type =
PseudoProbeDwarfDiscriminator::extractProbeType(Discriminator);
auto Attr = PseudoProbeDwarfDiscriminator::extractProbeAttributes(
Discriminator);
// Round small factors to 0 to avoid over-counting.
uint32_t IntFactor =
PseudoProbeDwarfDiscriminator::FullDistributionFactor;
if (Factor < 1)
IntFactor *= Factor;
uint32_t V = PseudoProbeDwarfDiscriminator::packProbeData(
Index, Type, Attr, IntFactor);
DIL = DIL->cloneWithDiscriminator(V);
Inst.setDebugLoc(DIL);
}
}
}
}
} // namespace llvm