1 //===- CLog.h - Logging Interface -------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_CLANG_TOOLS_LIBCLANG_CLOG_H
11 #define LLVM_CLANG_TOOLS_LIBCLANG_CLOG_H
12 
13 #include "clang-c/Index.h"
14 #include "clang/Basic/LLVM.h"
15 #include "llvm/ADT/IntrusiveRefCntPtr.h"
16 #include "llvm/ADT/SmallString.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/Support/Compiler.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include <string>
21 
22 namespace llvm {
23 class format_object_base;
24 }
25 
26 namespace clang {
27   class FileEntry;
28 
29 namespace cxindex {
30 
31 class Logger;
32 typedef IntrusiveRefCntPtr<Logger> LogRef;
33 
34 /// \brief Collects logging output and writes it to stderr when it's destructed.
35 /// Common use case:
36 /// \code
37 ///   if (LogRef Log = Logger::make(__func__)) {
38 ///     *Log << "stuff";
39 ///   }
40 /// \endcode
41 class Logger : public RefCountedBase<Logger> {
42   std::string Name;
43   bool Trace;
44   SmallString<64> Msg;
45   llvm::raw_svector_ostream LogOS;
46 public:
getEnvVar()47   static const char *getEnvVar() {
48     static const char *sCachedVar = ::getenv("LIBCLANG_LOGGING");
49     return sCachedVar;
50   }
isLoggingEnabled()51   static bool isLoggingEnabled() { return getEnvVar() != nullptr; }
isStackTracingEnabled()52   static bool isStackTracingEnabled() {
53     if (const char *EnvOpt = Logger::getEnvVar())
54       return llvm::StringRef(EnvOpt) == "2";
55     return false;
56   }
57   static LogRef make(llvm::StringRef name,
58                      bool trace = isStackTracingEnabled()) {
59     if (isLoggingEnabled())
60       return new Logger(name, trace);
61     return nullptr;
62   }
63 
Logger(llvm::StringRef name,bool trace)64   explicit Logger(llvm::StringRef name, bool trace)
65     : Name(name), Trace(trace), LogOS(Msg) { }
66   ~Logger();
67 
68   Logger &operator<<(CXTranslationUnit);
69   Logger &operator<<(const FileEntry *FE);
70   Logger &operator<<(CXCursor cursor);
71   Logger &operator<<(CXSourceLocation);
72   Logger &operator<<(CXSourceRange);
73   Logger &operator<<(CXString);
74   Logger &operator<<(llvm::StringRef Str) { LogOS << Str; return *this; }
75   Logger &operator<<(const char *Str) {
76     if (Str)
77       LogOS << Str;
78     return *this;
79   }
80   Logger &operator<<(unsigned long N) { LogOS << N; return *this; }
81   Logger &operator<<(long N) { LogOS << N ; return *this; }
82   Logger &operator<<(unsigned int N) { LogOS << N; return *this; }
83   Logger &operator<<(int N) { LogOS << N; return *this; }
84   Logger &operator<<(char C) { LogOS << C; return *this; }
85   Logger &operator<<(unsigned char C) { LogOS << C; return *this; }
86   Logger &operator<<(signed char C) { LogOS << C; return *this; }
87   Logger &operator<<(const llvm::format_object_base &Fmt);
88 };
89 
90 }
91 }
92 
93 /// \brief Macros to automate common uses of Logger. Like this:
94 /// \code
95 ///   LOG_FUNC_SECTION {
96 ///     *Log << "blah";
97 ///   }
98 /// \endcode
99 #define LOG_SECTION(NAME) \
100     if (clang::cxindex::LogRef Log = clang::cxindex::Logger::make(NAME))
101 #define LOG_FUNC_SECTION LOG_SECTION(LLVM_FUNCTION_NAME)
102 
103 #endif
104