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 (uint32_t Value) { |
62 | return (Value >> 3) & 0xFFFF; |
63 | } |
64 | |
65 | static uint32_t (uint32_t Value) { |
66 | return (Value >> 26) & 0x7; |
67 | } |
68 | |
69 | static uint32_t (uint32_t Value) { |
70 | return (Value >> 29) & 0x7; |
71 | } |
72 | |
73 | static uint32_t (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> (const Instruction &Inst); |
112 | |
113 | void setProbeDistributionFactor(Instruction &Inst, float Factor); |
114 | } // end namespace llvm |
115 | |
116 | #endif // LLVM_IR_PSEUDOPROBE_H |
117 | |