1 //===- SymbolRemappingReader.h - Read symbol remapping file -----*- 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 // This file contains definitions needed for reading and applying symbol
10 // remapping files.
11 //
12 // Support is provided only for the Itanium C++ name mangling scheme for now.
13 //
14 // NOTE: If you are making changes to this file format, please remember
15 //       to document them in the Clang documentation at
16 //       tools/clang/docs/UsersManual.rst.
17 //
18 // File format
19 // -----------
20 //
21 // The symbol remappings are written as an ASCII text file. Blank lines and
22 // lines starting with a # are ignored. All other lines specify a kind of
23 // mangled name fragment, along with two fragments of that kind that should
24 // be treated as equivalent, separated by spaces.
25 //
26 // See http://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling for a
27 // description of the Itanium name mangling scheme.
28 //
29 // The accepted fragment kinds are:
30 //
31 //  * name  A <name>, such as 6foobar or St3__1
32 //  * type  A <type>, such as Ss or N4llvm9StringRefE
33 //  * encoding  An <encoding> (a complete mangling without the leading _Z)
34 //
35 // For example:
36 //
37 // # Ignore int / long differences to treat symbols from 32-bit and 64-bit
38 // # builds with differing size_t / ptrdiff_t / intptr_t as equivalent.
39 // type i l
40 // type j m
41 //
42 // # Ignore differences between libc++ and libstdc++, and between libstdc++'s
43 // # C++98 and C++11 ABIs.
44 // name 3std St3__1
45 // name 3std St7__cxx11
46 //
47 // # Remap a function overload to a specialization of a template (including
48 // # any local symbols declared within it).
49 // encoding N2NS1fEi N2NS1fIiEEvT_
50 //
51 // # Substitutions must be remapped separately from namespace 'std' for now.
52 // name Sa NSt3__19allocatorE
53 // name Sb NSt3__112basic_stringE
54 // type Ss NSt3__112basic_stringIcSt11char_traitsIcESaE
55 // # ...
56 //
57 //===----------------------------------------------------------------------===//
58 
59 #ifndef LLVM_PROFILEDATA_SYMBOLREMAPPINGREADER_H
60 #define LLVM_PROFILEDATA_SYMBOLREMAPPINGREADER_H
61 
62 #include "llvm/ADT/StringRef.h"
63 #include "llvm/ProfileData/ItaniumManglingCanonicalizer.h"
64 #include "llvm/Support/Error.h"
65 
66 namespace llvm {
67 
68 class MemoryBuffer;
69 
70 class SymbolRemappingParseError : public ErrorInfo<SymbolRemappingParseError> {
71 public:
72   SymbolRemappingParseError(StringRef File, int64_t Line, const Twine &Message)
73       : File(File), Line(Line), Message(Message.str()) {}
74 
75   void log(llvm::raw_ostream &OS) const override {
76     OS << File << ':' << Line << ": " << Message;
77   }
78   std::error_code convertToErrorCode() const override {
79     return llvm::inconvertibleErrorCode();
80   }
81 
82   StringRef getFileName() const { return File; }
83   int64_t getLineNum() const { return Line; }
84   StringRef getMessage() const { return Message; }
85 
86   static char ID;
87 
88 private:
89   std::string File;
90   int64_t Line;
91   std::string Message;
92 };
93 
94 /// Reader for symbol remapping files.
95 ///
96 /// Remaps the symbol names in profile data to match those in the program
97 /// according to a set of rules specified in a given file.
98 class SymbolRemappingReader {
99 public:
100   /// Read remappings from the given buffer, which must live as long as
101   /// the remapper.
102   Error read(MemoryBuffer &B);
103 
104   /// A Key represents an equivalence class of symbol names.
105   using Key = uintptr_t;
106 
107   /// Construct a key for the given symbol, or return an existing one if an
108   /// equivalent name has already been inserted. The symbol name must live
109   /// as long as the remapper.
110   ///
111   /// The result will be Key() if the name cannot be remapped (typically
112   /// because it is not a valid mangled name).
113   Key insert(StringRef FunctionName) {
114     return Canonicalizer.canonicalize(FunctionName);
115   }
116 
117   /// Map the given symbol name into the key for the corresponding equivalence
118   /// class.
119   ///
120   /// The result will typically be Key() if no equivalent symbol has been
121   /// inserted, but this is not guaranteed: a Key different from all keys ever
122   /// returned by \c insert may be returned instead.
123   Key lookup(StringRef FunctionName) {
124     return Canonicalizer.lookup(FunctionName);
125   }
126 
127 private:
128   ItaniumManglingCanonicalizer Canonicalizer;
129 };
130 
131 } // end namespace llvm
132 
133 #endif // LLVM_PROFILEDATA_SYMBOLREMAPPINGREADER_H
134