1 // Copyright 2018 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // An async-signal-safe and thread-safe demangler for Itanium C++ ABI 16 // (aka G++ V3 ABI). 17 // 18 // The demangler is implemented to be used in async signal handlers to 19 // symbolize stack traces. We cannot use libstdc++'s 20 // abi::__cxa_demangle() in such signal handlers since it's not async 21 // signal safe (it uses malloc() internally). 22 // 23 // Note that this demangler doesn't support full demangling. More 24 // specifically, it doesn't print types of function parameters and 25 // types of template arguments. It just skips them. However, it's 26 // still very useful to extract basic information such as class, 27 // function, constructor, destructor, and operator names. 28 // 29 // See the implementation note in demangle.cc if you are interested. 30 // 31 // Example: 32 // 33 // | Mangled Name | The Demangler | abi::__cxa_demangle() 34 // |---------------|---------------|----------------------- 35 // | _Z1fv | f() | f() 36 // | _Z1fi | f() | f(int) 37 // | _Z3foo3bar | foo() | foo(bar) 38 // | _Z1fIiEvi | f<>() | void f<int>(int) 39 // | _ZN1N1fE | N::f | N::f 40 // | _ZN3Foo3BarEv | Foo::Bar() | Foo::Bar() 41 // | _Zrm1XS_" | operator%() | operator%(X, X) 42 // | _ZN3FooC1Ev | Foo::Foo() | Foo::Foo() 43 // | _Z1fSs | f() | f(std::basic_string<char, 44 // | | | std::char_traits<char>, 45 // | | | std::allocator<char> >) 46 // 47 // See the unit test for more examples. 48 // 49 // Note: we might want to write demanglers for ABIs other than Itanium 50 // C++ ABI in the future. 51 // 52 53 #ifndef ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_ 54 #define ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_ 55 56 #include "absl/base/config.h" 57 58 namespace absl { 59 ABSL_NAMESPACE_BEGIN 60 namespace debugging_internal { 61 62 // Demangle `mangled`. On success, return true and write the 63 // demangled symbol name to `out`. Otherwise, return false. 64 // `out` is modified even if demangling is unsuccessful. 65 bool Demangle(const char *mangled, char *out, int out_size); 66 67 } // namespace debugging_internal 68 ABSL_NAMESPACE_END 69 } // namespace absl 70 71 #endif // ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_ 72