debugging/internal/demangle.h

0001 // Copyright 2018 The Abseil Authors.
0002 //
0003 // Licensed under the Apache License, Version 2.0 (the "License");
0004 // you may not use this file except in compliance with the License.
0005 // You may obtain a copy of the License at
0006 //
0007 //      https://www.apache.org/licenses/LICENSE-2.0
0008 //
0009 // Unless required by applicable law or agreed to in writing, software
0010 // distributed under the License is distributed on an "AS IS" BASIS,
0011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0012 // See the License for the specific language governing permissions and
0013 // limitations under the License.
0014
0015 #ifndef ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_
0016 #define ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_
0017
0018 #include <string>
0019 #include "absl/base/config.h"
0020
0021 namespace absl {
0022 ABSL_NAMESPACE_BEGIN
0023 namespace debugging_internal {
0024
0025 // Demangle `mangled`.  On success, return true and write the
0026 // demangled symbol name to `out`.  Otherwise, return false.
0027 // `out` is modified even if demangling is unsuccessful.
0028 //
0029 // This function provides an alternative to libstdc++'s abi::__cxa_demangle,
0030 // which is not async signal safe (it uses malloc internally).  It's intended to
0031 // be used in async signal handlers to symbolize stack traces.
0032 //
0033 // Note that this demangler doesn't support full demangling.  More
0034 // specifically, it doesn't print types of function parameters and
0035 // types of template arguments.  It just skips them.  However, it's
0036 // still very useful to extract basic information such as class,
0037 // function, constructor, destructor, and operator names.
0038 //
0039 // See the implementation note in demangle.cc if you are interested.
0040 //
0041 // Example:
0042 //
0043 // | Mangled Name  | Demangle    | DemangleString
0044 // |---------------|-------------|-----------------------
0045 // | _Z1fv         | f()         | f()
0046 // | _Z1fi         | f()         | f(int)
0047 // | _Z3foo3bar    | foo()       | foo(bar)
0048 // | _Z1fIiEvi     | f<>()       | void f<int>(int)
0049 // | _ZN1N1fE      | N::f        | N::f
0050 // | _ZN3Foo3BarEv | Foo::Bar()  | Foo::Bar()
0051 // | _Zrm1XS_"     | operator%() | operator%(X, X)
0052 // | _ZN3FooC1Ev   | Foo::Foo()  | Foo::Foo()
0053 // | _Z1fSs        | f()         | f(std::basic_string<char,
0054 // |               |             |   std::char_traits<char>,
0055 // |               |             |   std::allocator<char> >)
0056 //
0057 // See the unit test for more examples.
0058 //
0059 // Demangle also recognizes Rust mangled names by delegating the parsing of
0060 // anything that starts with _R to DemangleRustSymbolEncoding (demangle_rust.h).
0061 //
0062 // Note: we might want to write demanglers for ABIs other than Itanium
0063 // C++ ABI in the future.
0064 bool Demangle(const char* mangled, char* out, size_t out_size);
0065
0066 // A wrapper around `abi::__cxa_demangle()`.  On success, returns the demangled
0067 // name.  On failure, returns the input mangled name.
0068 //
0069 // This function is not async-signal-safe.
0070 std::string DemangleString(const char* mangled);
0071
0072 }  // namespace debugging_internal
0073 ABSL_NAMESPACE_END
0074 }  // namespace absl
0075
0076 #endif  // ABSL_DEBUGGING_INTERNAL_DEMANGLE_H_