1 //===- PseudoProbe.h - Pseudo Probe IR Helpers ------------------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // Pseudo probe IR intrinsic and dwarf discriminator manipulation routines.
11 //===----------------------------------------------------------------------===//
13 #ifndef LLVM_IR_PSEUDOPROBE_H
14 #define LLVM_IR_PSEUDOPROBE_H
16 #include "llvm/ADT/Optional.h"
25 constexpr const char *PseudoProbeDescMetadataName = "llvm.pseudo_probe_desc";
27 enum class PseudoProbeType { Block = 0, IndirectCall, DirectCall };
29 // The saturated distrution factor representing 100% for block probes.
30 constexpr static uint64_t PseudoProbeFullDistributionFactor =
31 std::numeric_limits<uint64_t>::max();
33 struct PseudoProbeDwarfDiscriminator {
35 // The following APIs encodes/decodes per-probe information to/from a
36 // 32-bit integer which is organized as:
37 // [2:0] - 0x7, this is reserved for regular discriminator,
38 // see DWARF discriminator encoding rule
40 // [25:19] - probe distribution factor
41 // [28:26] - probe type, see PseudoProbeType
42 // [31:29] - reserved for probe attributes
43 static uint32_t packProbeData(uint32_t Index, uint32_t Type, uint32_t Flags,
45 assert(Index <= 0xFFFF && "Probe index too big to encode, exceeding 2^16");
46 assert(Type <= 0x7 && "Probe type too big to encode, exceeding 7");
48 assert(Factor <= 100 &&
49 "Probe distribution factor too big to encode, exceeding 100");
50 return (Index << 3) | (Factor << 19) | (Type << 26) | 0x7;
53 static uint32_t extractProbeIndex(uint32_t Value) {
54 return (Value >> 3) & 0xFFFF;
57 static uint32_t extractProbeType(uint32_t Value) {
58 return (Value >> 26) & 0x7;
61 static uint32_t extractProbeAttributes(uint32_t Value) {
62 return (Value >> 29) & 0x7;
65 static uint32_t extractProbeFactor(uint32_t Value) {
66 return (Value >> 19) & 0x7F;
69 // The saturated distrution factor representing 100% for callsites.
70 constexpr static uint8_t FullDistributionFactor = 100;
77 // Distribution factor that estimates the portion of the real execution count.
78 // A saturated distribution factor stands for 1.0 or 100%. A pesudo probe has
79 // a factor with the value ranged from 0.0 to 1.0.
83 Optional<PseudoProbe> extractProbe(const Instruction &Inst);
85 void setProbeDistributionFactor(Instruction &Inst, float Factor);
86 } // end namespace llvm
88 #endif // LLVM_IR_PSEUDOPROBE_H