///===- MachineOptimizationRemarkEmitter.h - Opt Diagnostics -*- 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
/// Optimization diagnostic interfaces for machine passes. It's packaged as an
/// analysis pass so that by using this service passes become dependent on MBFI
/// as well. MBFI is used to compute the "hotness" of the diagnostic message.
///
///===---------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEOPTIMIZATIONREMARKEMITTER_H
#define LLVM_CODEGEN_MACHINEOPTIMIZATIONREMARKEMITTER_H
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include <optional>
namespace llvm {
class MachineBasicBlock;
class MachineBlockFrequencyInfo;
class MachineInstr;
/// Common features for diagnostics dealing with optimization remarks
/// that are used by machine passes.
class DiagnosticInfoMIROptimization : public DiagnosticInfoOptimizationBase {
public:
DiagnosticInfoMIROptimization(enum DiagnosticKind Kind, const char *PassName,
StringRef RemarkName,
const DiagnosticLocation &Loc,
const MachineBasicBlock *MBB)
: DiagnosticInfoOptimizationBase(Kind, DS_Remark, PassName, RemarkName,
MBB->getParent()->getFunction(), Loc),
MBB(MBB) {}
/// MI-specific kinds of diagnostic Arguments.
struct MachineArgument : public DiagnosticInfoOptimizationBase::Argument {
/// Print an entire MachineInstr.
MachineArgument(StringRef Key, const MachineInstr &MI);
};
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() >= DK_FirstMachineRemark &&
DI->getKind() <= DK_LastMachineRemark;
}
const MachineBasicBlock *getBlock() const { return MBB; }
private:
const MachineBasicBlock *MBB;
};
/// Diagnostic information for applied optimization remarks.
class MachineOptimizationRemark : public DiagnosticInfoMIROptimization {
public:
/// \p PassName is the name of the pass emitting this diagnostic. If this name
/// matches the regular expression given in -Rpass=, then the diagnostic will
/// be emitted. \p RemarkName is a textual identifier for the remark. \p
/// Loc is the debug location and \p MBB is the block that the optimization
/// operates in.
MachineOptimizationRemark(const char *PassName, StringRef RemarkName,
const DiagnosticLocation &Loc,
const MachineBasicBlock *MBB)
: DiagnosticInfoMIROptimization(DK_MachineOptimizationRemark, PassName,
RemarkName, Loc, MBB) {}
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() == DK_MachineOptimizationRemark;
}
/// \see DiagnosticInfoOptimizationBase::isEnabled.
bool isEnabled() const override {
const Function &Fn = getFunction();
LLVMContext &Ctx = Fn.getContext();
return Ctx.getDiagHandlerPtr()->isPassedOptRemarkEnabled(getPassName());
}
};
/// Diagnostic information for missed-optimization remarks.
class MachineOptimizationRemarkMissed : public DiagnosticInfoMIROptimization {
public:
/// \p PassName is the name of the pass emitting this diagnostic. If this name
/// matches the regular expression given in -Rpass-missed=, then the
/// diagnostic will be emitted. \p RemarkName is a textual identifier for the
/// remark. \p Loc is the debug location and \p MBB is the block that the
/// optimization operates in.
MachineOptimizationRemarkMissed(const char *PassName, StringRef RemarkName,
const DiagnosticLocation &Loc,
const MachineBasicBlock *MBB)
: DiagnosticInfoMIROptimization(DK_MachineOptimizationRemarkMissed,
PassName, RemarkName, Loc, MBB) {}
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() == DK_MachineOptimizationRemarkMissed;
}
/// \see DiagnosticInfoOptimizationBase::isEnabled.
bool isEnabled() const override {
const Function &Fn = getFunction();
LLVMContext &Ctx = Fn.getContext();
return Ctx.getDiagHandlerPtr()->isMissedOptRemarkEnabled(getPassName());
}
};
/// Diagnostic information for optimization analysis remarks.
class MachineOptimizationRemarkAnalysis : public DiagnosticInfoMIROptimization {
public:
/// \p PassName is the name of the pass emitting this diagnostic. If this name
/// matches the regular expression given in -Rpass-analysis=, then the
/// diagnostic will be emitted. \p RemarkName is a textual identifier for the
/// remark. \p Loc is the debug location and \p MBB is the block that the
/// optimization operates in.
MachineOptimizationRemarkAnalysis(const char *PassName, StringRef RemarkName,
const DiagnosticLocation &Loc,
const MachineBasicBlock *MBB)
: DiagnosticInfoMIROptimization(DK_MachineOptimizationRemarkAnalysis,
PassName, RemarkName, Loc, MBB) {}
MachineOptimizationRemarkAnalysis(const char *PassName, StringRef RemarkName,
const MachineInstr *MI)
: DiagnosticInfoMIROptimization(DK_MachineOptimizationRemarkAnalysis,
PassName, RemarkName, MI->getDebugLoc(),
MI->getParent()) {}
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() == DK_MachineOptimizationRemarkAnalysis;
}
/// \see DiagnosticInfoOptimizationBase::isEnabled.
bool isEnabled() const override {
const Function &Fn = getFunction();
LLVMContext &Ctx = Fn.getContext();
return Ctx.getDiagHandlerPtr()->isAnalysisRemarkEnabled(getPassName());
}
};
/// Extend llvm::ore:: with MI-specific helper names.
namespace ore {
using MNV = DiagnosticInfoMIROptimization::MachineArgument;
}
/// The optimization diagnostic interface.
///
/// It allows reporting when optimizations are performed and when they are not
/// along with the reasons for it. Hotness information of the corresponding
/// code region can be included in the remark if DiagnosticsHotnessRequested is
/// enabled in the LLVM context.
class MachineOptimizationRemarkEmitter {
public:
MachineOptimizationRemarkEmitter(MachineFunction &MF,
MachineBlockFrequencyInfo *MBFI)
: MF(MF), MBFI(MBFI) {}
/// Emit an optimization remark.
void emit(DiagnosticInfoOptimizationBase &OptDiag);
/// Whether we allow for extra compile-time budget to perform more
/// analysis to be more informative.
///
/// This is useful to enable additional missed optimizations to be reported
/// that are normally too noisy. In this mode, we can use the extra analysis
/// (1) to filter trivial false positives or (2) to provide more context so
/// that non-trivial false positives can be quickly detected by the user.
bool allowExtraAnalysis(StringRef PassName) const {
return (
MF.getFunction().getContext().getLLVMRemarkStreamer() ||
MF.getFunction().getContext().getDiagHandlerPtr()->isAnyRemarkEnabled(
PassName));
}
/// Take a lambda that returns a remark which will be emitted. Second
/// argument is only used to restrict this to functions.
template <typename T>
void emit(T RemarkBuilder, decltype(RemarkBuilder()) * = nullptr) {
// Avoid building the remark unless we know there are at least *some*
// remarks enabled. We can't currently check whether remarks are requested
// for the calling pass since that requires actually building the remark.
if (MF.getFunction().getContext().getLLVMRemarkStreamer() ||
MF.getFunction()
.getContext()
.getDiagHandlerPtr()
->isAnyRemarkEnabled()) {
auto R = RemarkBuilder();
emit((DiagnosticInfoOptimizationBase &)R);
}
}
MachineBlockFrequencyInfo *getBFI() {
return MBFI;
}
private:
MachineFunction &MF;
/// MBFI is only set if hotness is requested.
MachineBlockFrequencyInfo *MBFI;
/// Compute hotness from IR value (currently assumed to be a block) if PGO is
/// available.
std::optional<uint64_t> computeHotness(const MachineBasicBlock &MBB);
/// Similar but use value from \p OptDiag and update hotness there.
void computeHotness(DiagnosticInfoMIROptimization &Remark);
/// Only allow verbose messages if we know we're filtering by hotness
/// (BFI is only set in this case).
bool shouldEmitVerbose() { return MBFI != nullptr; }
};
/// The analysis pass
///
/// Note that this pass shouldn't generally be marked as preserved by other
/// passes. It's holding onto BFI, so if the pass does not preserve BFI, BFI
/// could be freed.
class MachineOptimizationRemarkEmitterPass : public MachineFunctionPass {
std::unique_ptr<MachineOptimizationRemarkEmitter> ORE;
public:
MachineOptimizationRemarkEmitterPass();
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
MachineOptimizationRemarkEmitter &getORE() {
assert(ORE && "pass not run yet");
return *ORE;
}
static char ID;
};
}
#endif