1 // Copyright 2012 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_LOCATION_H_
6 #define BASE_LOCATION_H_
10 #include "base/base_export.h"
11 #include "base/debug/debugging_buildflags.h"
12 #include "base/memory/raw_ptr_exclusion.h"
13 #include "base/trace_event/base_tracing_forward.h"
14 #include "build/build_config.h"
18 #if defined(__clang__)
19 // Clang allows detection of these builtins.
20 #define SUPPORTS_LOCATION_BUILTINS \
21 (__has_builtin(__builtin_FUNCTION) && __has_builtin(__builtin_FILE) && \
22 __has_builtin(__builtin_LINE))
23 #elif defined(COMPILER_GCC) && __GNUC__ >= 7
24 // GCC has supported these for a long time, but they point at the function
25 // declaration in the case of default arguments, rather than at the call site.
26 #define SUPPORTS_LOCATION_BUILTINS 1
28 #define SUPPORTS_LOCATION_BUILTINS 0
31 // Location provides basic info where of an object was constructed, or was
32 // significantly brought to life.
33 class BASE_EXPORT Location {
36 Location(const Location& other);
37 Location(Location&& other) noexcept;
38 Location& operator=(const Location& other);
40 // Only initializes the file name and program counter, the source information
41 // will be null for the strings, and -1 for the line number.
42 // TODO(http://crbug.com/760702) remove file name from this constructor.
43 Location(const char* file_name, const void* program_counter);
45 // Constructor should be called with a long-lived char*, such as __FILE__.
46 // It assumes the provided value will persist as a global constant, and it
47 // will not make a copy of it.
48 Location(const char* function_name,
49 const char* file_name,
51 const void* program_counter);
53 // Comparator for testing. The program counter should uniquely
54 // identify a location.
55 bool operator==(const Location& other) const {
56 return program_counter_ == other.program_counter_;
59 // Comparator is necessary to use location object within an ordered container
60 // type (eg. std::map).
61 bool operator<(const Location& other) const {
62 return program_counter_ < other.program_counter_;
65 // Returns true if there is source code location info. If this is false,
66 // the Location object only contains a program counter or is
67 // default-initialized (the program counter is also null).
68 bool has_source_info() const { return function_name_ && file_name_; }
70 // Will be nullptr for default initialized Location objects and when source
71 // names are disabled.
72 const char* function_name() const { return function_name_; }
74 // Will be nullptr for default initialized Location objects and when source
75 // names are disabled.
76 const char* file_name() const { return file_name_; }
78 // Will be -1 for default initialized Location objects and when source names
80 int line_number() const { return line_number_; }
82 // The address of the code generating this Location object. Should always be
83 // valid except for default initialized Location objects, which will be
85 const void* program_counter() const { return program_counter_; }
87 // Converts to the most user-readable form possible. If function and filename
88 // are not available, this will return "pc:<hex address>".
89 std::string ToString() const;
91 // Write a representation of this object into a trace.
92 void WriteIntoTrace(perfetto::TracedValue context) const;
94 #if !BUILDFLAG(FROM_HERE_USES_LOCATION_BUILTINS)
95 #if !BUILDFLAG(ENABLE_LOCATION_SOURCE)
96 static Location CreateFromHere(const char* file_name);
98 static Location CreateFromHere(const char* function_name,
99 const char* file_name,
104 #if SUPPORTS_LOCATION_BUILTINS && BUILDFLAG(ENABLE_LOCATION_SOURCE)
105 static Location Current(const char* function_name = __builtin_FUNCTION(),
106 const char* file_name = __builtin_FILE(),
107 int line_number = __builtin_LINE());
108 #elif SUPPORTS_LOCATION_BUILTINS
109 static Location Current(const char* file_name = __builtin_FILE());
111 static Location Current();
115 const char* function_name_ = nullptr;
116 const char* file_name_ = nullptr;
117 int line_number_ = -1;
119 // `program_counter_` is not a raw_ptr<...> for performance reasons (based on
120 // analysis of sampling profiler data and tab_search:top100:2020).
121 RAW_PTR_EXCLUSION const void* program_counter_ = nullptr;
124 BASE_EXPORT const void* GetProgramCounter();
126 #if BUILDFLAG(FROM_HERE_USES_LOCATION_BUILTINS)
128 #define FROM_HERE ::base::Location::Current()
130 // The macros defined here will expand to the current function.
131 #elif BUILDFLAG(ENABLE_LOCATION_SOURCE)
133 // Full source information should be included.
134 #define FROM_HERE ::base::Location::CreateFromHere(__func__, __FILE__, __LINE__)
138 // TODO(http://crbug.com/760702) remove the __FILE__ argument from these calls.
139 #define FROM_HERE ::base::Location::CreateFromHere(__FILE__)
145 #endif // BASE_LOCATION_H_