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_SUPPORT_SYMBOLREMAPPINGREADER_H 60 #define LLVM_SUPPORT_SYMBOLREMAPPINGREADER_H 61 62 #include "llvm/ADT/StringRef.h" 63 #include "llvm/Support/Error.h" 64 #include "llvm/Support/ItaniumManglingCanonicalizer.h" 65 #include "llvm/Support/MemoryBuffer.h" 66 67 namespace llvm { 68 69 class SymbolRemappingParseError : public ErrorInfo<SymbolRemappingParseError> { 70 public: SymbolRemappingParseError(StringRef File,int64_t Line,Twine Message)71 SymbolRemappingParseError(StringRef File, int64_t Line, Twine Message) 72 : File(File), Line(Line), Message(Message.str()) {} 73 log(llvm::raw_ostream & OS)74 void log(llvm::raw_ostream &OS) const override { 75 OS << File << ':' << Line << ": " << Message; 76 } convertToErrorCode()77 std::error_code convertToErrorCode() const override { 78 return llvm::inconvertibleErrorCode(); 79 } 80 getFileName()81 StringRef getFileName() const { return File; } getLineNum()82 int64_t getLineNum() const { return Line; } getMessage()83 StringRef getMessage() const { return Message; } 84 85 static char ID; 86 87 private: 88 std::string File; 89 int64_t Line; 90 std::string Message; 91 }; 92 93 /// Reader for symbol remapping files. 94 /// 95 /// Remaps the symbol names in profile data to match those in the program 96 /// according to a set of rules specified in a given file. 97 class SymbolRemappingReader { 98 public: 99 /// Read remappings from the given buffer, which must live as long as 100 /// the remapper. 101 Error read(MemoryBuffer &B); 102 103 /// A Key represents an equivalence class of symbol names. 104 using Key = uintptr_t; 105 106 /// Construct a key for the given symbol, or return an existing one if an 107 /// equivalent name has already been inserted. The symbol name must live 108 /// as long as the remapper. 109 /// 110 /// The result will be Key() if the name cannot be remapped (typically 111 /// because it is not a valid mangled name). insert(StringRef FunctionName)112 Key insert(StringRef FunctionName) { 113 return Canonicalizer.canonicalize(FunctionName); 114 } 115 116 /// Map the given symbol name into the key for the corresponding equivalence 117 /// class. 118 /// 119 /// The result will typically be Key() if no equivalent symbol has been 120 /// inserted, but this is not guaranteed: a Key different from all keys ever 121 /// returned by \c insert may be returned instead. lookup(StringRef FunctionName)122 Key lookup(StringRef FunctionName) { 123 return Canonicalizer.lookup(FunctionName); 124 } 125 126 private: 127 ItaniumManglingCanonicalizer Canonicalizer; 128 }; 129 130 } // end namespace llvm 131 132 #endif // LLVM_SUPPORT_SYMBOLREMAPPINGREADER_H 133