1 //===- InstrumentationMap.h - XRay Instrumentation Map ----------*- 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 // Defines the interface for extracting the instrumentation map from an
10 // XRay-instrumented binary.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_XRAY_INSTRUMENTATION_MAP_H
15 #define LLVM_XRAY_INSTRUMENTATION_MAP_H
16 
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/Support/Error.h"
20 #include "llvm/Support/YAMLTraits.h"
21 #include <cstdint>
22 #include <unordered_map>
23 #include <vector>
24 
25 namespace llvm {
26 
27 namespace xray {
28 
29 // Forward declare to make a friend.
30 class InstrumentationMap;
31 
32 /// Loads the instrumentation map from |Filename|. This auto-deduces the type of
33 /// the instrumentation map.
34 Expected<InstrumentationMap> loadInstrumentationMap(StringRef Filename);
35 
36 /// Represents an XRay instrumentation sled entry from an object file.
37 struct SledEntry {
38   /// Each entry here represents the kinds of supported instrumentation map
39   /// entries.
40   enum class FunctionKinds { ENTRY, EXIT, TAIL, LOG_ARGS_ENTER, CUSTOM_EVENT };
41 
42   /// The address of the sled.
43   uint64_t Address;
44 
45   /// The address of the function.
46   uint64_t Function;
47 
48   /// The kind of sled.
49   FunctionKinds Kind;
50 
51   /// Whether the sled was annotated to always be instrumented.
52   bool AlwaysInstrument;
53 };
54 
55 struct YAMLXRaySledEntry {
56   int32_t FuncId;
57   yaml::Hex64 Address;
58   yaml::Hex64 Function;
59   SledEntry::FunctionKinds Kind;
60   bool AlwaysInstrument;
61   std::string FunctionName;
62 };
63 
64 /// The InstrumentationMap represents the computed function id's and indicated
65 /// function addresses from an object file (or a YAML file). This provides an
66 /// interface to just the mapping between the function id, and the function
67 /// address.
68 ///
69 /// We also provide raw access to the actual instrumentation map entries we find
70 /// associated with a particular object file.
71 ///
72 class InstrumentationMap {
73 public:
74   using FunctionAddressMap = std::unordered_map<int32_t, uint64_t>;
75   using FunctionAddressReverseMap = std::unordered_map<uint64_t, int32_t>;
76   using SledContainer = std::vector<SledEntry>;
77 
78 private:
79   SledContainer Sleds;
80   FunctionAddressMap FunctionAddresses;
81   FunctionAddressReverseMap FunctionIds;
82 
83   friend Expected<InstrumentationMap> loadInstrumentationMap(StringRef);
84 
85 public:
86   /// Provides a raw accessor to the unordered map of function addresses.
getFunctionAddresses()87   const FunctionAddressMap &getFunctionAddresses() { return FunctionAddresses; }
88 
89   /// Returns an XRay computed function id, provided a function address.
90   Optional<int32_t> getFunctionId(uint64_t Addr) const;
91 
92   /// Returns the function address for a function id.
93   Optional<uint64_t> getFunctionAddr(int32_t FuncId) const;
94 
95   /// Provide read-only access to the entries of the instrumentation map.
sleds()96   const SledContainer &sleds() const { return Sleds; };
97 };
98 
99 } // end namespace xray
100 
101 namespace yaml {
102 
103 template <> struct ScalarEnumerationTraits<xray::SledEntry::FunctionKinds> {
104   static void enumeration(IO &IO, xray::SledEntry::FunctionKinds &Kind) {
105     IO.enumCase(Kind, "function-enter", xray::SledEntry::FunctionKinds::ENTRY);
106     IO.enumCase(Kind, "function-exit", xray::SledEntry::FunctionKinds::EXIT);
107     IO.enumCase(Kind, "tail-exit", xray::SledEntry::FunctionKinds::TAIL);
108     IO.enumCase(Kind, "log-args-enter",
109                 xray::SledEntry::FunctionKinds::LOG_ARGS_ENTER);
110     IO.enumCase(Kind, "custom-event",
111                 xray::SledEntry::FunctionKinds::CUSTOM_EVENT);
112   }
113 };
114 
115 template <> struct MappingTraits<xray::YAMLXRaySledEntry> {
116   static void mapping(IO &IO, xray::YAMLXRaySledEntry &Entry) {
117     IO.mapRequired("id", Entry.FuncId);
118     IO.mapRequired("address", Entry.Address);
119     IO.mapRequired("function", Entry.Function);
120     IO.mapRequired("kind", Entry.Kind);
121     IO.mapRequired("always-instrument", Entry.AlwaysInstrument);
122     IO.mapOptional("function-name", Entry.FunctionName);
123   }
124 
125   static constexpr bool flow = true;
126 };
127 
128 } // end namespace yaml
129 
130 } // end namespace llvm
131 
132 LLVM_YAML_IS_SEQUENCE_VECTOR(xray::YAMLXRaySledEntry)
133 
134 #endif // LLVM_XRAY_INSTRUMENTATION_MAP_H
135