1 //===- PseudoProbe.h - Pseudo Probe IR Helpers ------------------*- C++ -*-===// 2 // 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 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Pseudo probe IR intrinsic and dwarf discriminator manipulation routines. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_IR_PSEUDOPROBE_H 14 #define LLVM_IR_PSEUDOPROBE_H 15 16 #include "llvm/ADT/Optional.h" 17 #include <cassert> 18 #include <cstdint> 19 #include <limits> 20 21 namespace llvm { 22 23 class Instruction; 24 25 constexpr const char *PseudoProbeDescMetadataName = "llvm.pseudo_probe_desc"; 26 27 enum class PseudoProbeType { Block = 0, IndirectCall, DirectCall }; 28 29 // The saturated distrution factor representing 100% for block probes. 30 constexpr static uint64_t PseudoProbeFullDistributionFactor = 31 std::numeric_limits<uint64_t>::max(); 32 33 struct PseudoProbeDwarfDiscriminator { 34 public: 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 39 // [18:3] - probe id 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, 44 uint32_t Factor) { 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"); 47 assert(Flags <= 0x7); 48 assert(Factor <= 100 && 49 "Probe distribution factor too big to encode, exceeding 100"); 50 return (Index << 3) | (Factor << 19) | (Type << 26) | 0x7; 51 } 52 53 static uint32_t extractProbeIndex(uint32_t Value) { 54 return (Value >> 3) & 0xFFFF; 55 } 56 57 static uint32_t extractProbeType(uint32_t Value) { 58 return (Value >> 26) & 0x7; 59 } 60 61 static uint32_t extractProbeAttributes(uint32_t Value) { 62 return (Value >> 29) & 0x7; 63 } 64 65 static uint32_t extractProbeFactor(uint32_t Value) { 66 return (Value >> 19) & 0x7F; 67 } 68 69 // The saturated distrution factor representing 100% for callsites. 70 constexpr static uint8_t FullDistributionFactor = 100; 71 }; 72 73 struct PseudoProbe { 74 uint32_t Id; 75 uint32_t Type; 76 uint32_t Attr; 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. 80 float Factor; 81 }; 82 83 Optional<PseudoProbe> extractProbe(const Instruction &Inst); 84 85 void setProbeDistributionFactor(Instruction &Inst, float Factor); 86 } // end namespace llvm 87 88 #endif // LLVM_IR_PSEUDOPROBE_H 89