1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 19:52:54 +01:00
llvm-mirror/include/llvm/IR/PseudoProbe.h
Hongtao Yu 7fbb587058 [CSSPGO] Undoing the concept of dangling pseudo probe
As a follow-up to https://reviews.llvm.org/D104129, I'm cleaning up the danling probe related code in both the compiler and llvm-profgen.

I'm seeing a 5% size win for the pseudo_probe section for SPEC2017 and 10% for Ciner. Certain benchmark such as 602.gcc has a 20% size win. No obvious difference seen on build time for SPEC2017 and Cinder.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D104477
2021-06-18 15:14:11 -07:00

94 lines
3.0 KiB
C++

//===- PseudoProbe.h - Pseudo Probe IR Helpers ------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Pseudo probe IR intrinsic and dwarf discriminator manipulation routines.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_PSEUDOPROBE_H
#define LLVM_IR_PSEUDOPROBE_H
#include "llvm/ADT/Optional.h"
#include <cassert>
#include <cstdint>
#include <limits>
namespace llvm {
class Instruction;
class BasicBlock;
constexpr const char *PseudoProbeDescMetadataName = "llvm.pseudo_probe_desc";
enum class PseudoProbeType { Block = 0, IndirectCall, DirectCall };
enum class PseudoProbeAttributes {
Reserved = 0x1, // Reserved for future use.
};
// The saturated distrution factor representing 100% for block probes.
constexpr static uint64_t PseudoProbeFullDistributionFactor =
std::numeric_limits<uint64_t>::max();
struct PseudoProbeDwarfDiscriminator {
public:
// The following APIs encodes/decodes per-probe information to/from a
// 32-bit integer which is organized as:
// [2:0] - 0x7, this is reserved for regular discriminator,
// see DWARF discriminator encoding rule
// [18:3] - probe id
// [25:19] - probe distribution factor
// [28:26] - probe type, see PseudoProbeType
// [31:29] - reserved for probe attributes
static uint32_t packProbeData(uint32_t Index, uint32_t Type, uint32_t Flags,
uint32_t Factor) {
assert(Index <= 0xFFFF && "Probe index too big to encode, exceeding 2^16");
assert(Type <= 0x7 && "Probe type too big to encode, exceeding 7");
assert(Flags <= 0x7);
assert(Factor <= 100 &&
"Probe distribution factor too big to encode, exceeding 100");
return (Index << 3) | (Factor << 19) | (Type << 26) | 0x7;
}
static uint32_t extractProbeIndex(uint32_t Value) {
return (Value >> 3) & 0xFFFF;
}
static uint32_t extractProbeType(uint32_t Value) {
return (Value >> 26) & 0x7;
}
static uint32_t extractProbeAttributes(uint32_t Value) {
return (Value >> 29) & 0x7;
}
static uint32_t extractProbeFactor(uint32_t Value) {
return (Value >> 19) & 0x7F;
}
// The saturated distrution factor representing 100% for callsites.
constexpr static uint8_t FullDistributionFactor = 100;
};
struct PseudoProbe {
uint32_t Id;
uint32_t Type;
uint32_t Attr;
// Distribution factor that estimates the portion of the real execution count.
// A saturated distribution factor stands for 1.0 or 100%. A pesudo probe has
// a factor with the value ranged from 0.0 to 1.0.
float Factor;
};
Optional<PseudoProbe> extractProbe(const Instruction &Inst);
void setProbeDistributionFactor(Instruction &Inst, float Factor);
} // end namespace llvm
#endif // LLVM_IR_PSEUDOPROBE_H