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 <cassert> 17 #include <cstdint> 18 #include <limits> 19 #include <optional> 20 21 namespace llvm { 22 23 class Instruction; 24 25 constexpr const char *PseudoProbeDescMetadataName = "llvm.pseudo_probe_desc"; 26 27 enum class PseudoProbeReservedId { Invalid = 0, Last = Invalid }; 28 29 enum class PseudoProbeType { Block = 0, IndirectCall, DirectCall }; 30 31 enum class PseudoProbeAttributes { 32 Reserved = 0x1, 33 Sentinel = 0x2, // A place holder for split function entry address. 34 HasDiscriminator = 0x4, // for probes with a discriminator 35 }; 36 37 // The saturated distrution factor representing 100% for block probes. 38 constexpr static uint64_t PseudoProbeFullDistributionFactor = 39 std::numeric_limits<uint64_t>::max(); 40 41 struct PseudoProbeDwarfDiscriminator { 42 public: 43 // The following APIs encodes/decodes per-probe information to/from a 44 // 32-bit integer which is organized as: 45 // [2:0] - 0x7, this is reserved for regular discriminator, 46 // see DWARF discriminator encoding rule 47 // [18:3] - probe id 48 // [25:19] - probe distribution factor 49 // [28:26] - probe type, see PseudoProbeType 50 // [31:29] - reserved for probe attributes 51 static uint32_t packProbeData(uint32_t Index, uint32_t Type, uint32_t Flags, 52 uint32_t Factor) { 53 assert(Index <= 0xFFFF && "Probe index too big to encode, exceeding 2^16"); 54 assert(Type <= 0x7 && "Probe type too big to encode, exceeding 7"); 55 assert(Flags <= 0x7); 56 assert(Factor <= 100 && 57 "Probe distribution factor too big to encode, exceeding 100"); 58 return (Index << 3) | (Factor << 19) | (Type << 26) | 0x7; 59 } 60 61 static uint32_t extractProbeIndex(uint32_t Value) { 62 return (Value >> 3) & 0xFFFF; 63 } 64 65 static uint32_t extractProbeType(uint32_t Value) { 66 return (Value >> 26) & 0x7; 67 } 68 69 static uint32_t extractProbeAttributes(uint32_t Value) { 70 return (Value >> 29) & 0x7; 71 } 72 73 static uint32_t extractProbeFactor(uint32_t Value) { 74 return (Value >> 19) & 0x7F; 75 } 76 77 // The saturated distrution factor representing 100% for callsites. 78 constexpr static uint8_t FullDistributionFactor = 100; 79 }; 80 81 class PseudoProbeDescriptor { 82 uint64_t FunctionGUID; 83 uint64_t FunctionHash; 84 85 public: 86 PseudoProbeDescriptor(uint64_t GUID, uint64_t Hash) 87 : FunctionGUID(GUID), FunctionHash(Hash) {} 88 uint64_t getFunctionGUID() const { return FunctionGUID; } 89 uint64_t getFunctionHash() const { return FunctionHash; } 90 }; 91 92 struct PseudoProbe { 93 uint32_t Id; 94 uint32_t Type; 95 uint32_t Attr; 96 uint32_t Discriminator; 97 // Distribution factor that estimates the portion of the real execution count. 98 // A saturated distribution factor stands for 1.0 or 100%. A pesudo probe has 99 // a factor with the value ranged from 0.0 to 1.0. 100 float Factor; 101 }; 102 103 static inline bool isSentinelProbe(uint32_t Flags) { 104 return Flags & (uint32_t)PseudoProbeAttributes::Sentinel; 105 } 106 107 static inline bool hasDiscriminator(uint32_t Flags) { 108 return Flags & (uint32_t)PseudoProbeAttributes::HasDiscriminator; 109 } 110 111 std::optional<PseudoProbe> extractProbe(const Instruction &Inst); 112 113 void setProbeDistributionFactor(Instruction &Inst, float Factor); 114 } // end namespace llvm 115 116 #endif // LLVM_IR_PSEUDOPROBE_H 117