Debug.h revision a72ac422a22683b9ab872838be1a19445e3c1141 
1//===- llvm/Support/Debug.h - Easy way to add debug output ------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements a handle way of adding debugging information to your
11// code, without it being enabled all of the time, and without having to add
12// command line options to enable it.
13//
14// In particular, just wrap your code with the DEBUG() macro, and it will be
15// enabled automatically if you specify '-debug' on the command-line.
16// Alternatively, you can also use the SET_DEBUG_TYPE("foo") macro to specify
17// that your debug code belongs to class "foo".  Then, on the command line, you
18// can specify '-debug-only=foo' to enable JUST the debug information for the
19// foo class.
20//
21// When compiling in release mode, the -debug-* options and all code in DEBUG()
22// statements disappears, so it does not effect the runtime of the code.
23//
24//===----------------------------------------------------------------------===//
25
26#ifndef LLVM_SUPPORT_DEBUG_H
27#define LLVM_SUPPORT_DEBUG_H
28
29#include <ostream>              // Doesn't have static d'tors!!
30
31namespace llvm {
32
33// DebugFlag - This boolean is set to true if the '-debug' command line option
34// is specified.  This should probably not be referenced directly, instead, use
35// the DEBUG macro below.
36//
37extern bool DebugFlag;
38
39// isCurrentDebugType - Return true if the specified string is the debug type
40// specified on the command line, or if none was specified on the command line
41// with the -debug-only=X option.
42//
43bool isCurrentDebugType(const char *Type);
44
45// DEBUG macro - This macro should be used by passes to emit debug information.
46// In the '-debug' option is specified on the commandline, and if this is a
47// debug build, then the code specified as the option to the macro will be
48// executed.  Otherwise it will not be.  Example:
49//
50// DEBUG(cerr << "Bitset contains: " << Bitset << "\n");
51//
52
53#ifndef DEBUG_TYPE
54#define DEBUG_TYPE ""
55#endif
56
57#ifdef NDEBUG
58#define DEBUG(X)
59#else
60#define DEBUG(X) \
61  do { if (DebugFlag && isCurrentDebugType(DEBUG_TYPE)) { X; } } while (0)
62#endif
63
64/// llvm_ostream - Acts like an ostream. However, it doesn't print things out if
65/// an ostream isn't specified.
66///
67class llvm_ostream {
68  std::ostream* Stream;
69public:
70  llvm_ostream() : Stream(0) {}
71  llvm_ostream(std::ostream& OStream) : Stream(&OStream) {}
72
73  template <typename Ty>
74  llvm_ostream& operator << (const Ty& Thing) {
75#ifndef NDEBUG
76    if (Stream) *Stream << Thing;
77#endif
78    return *this;
79  }
80};
81
82/// getErrorOutputStream - Returns the error output stream (std::cerr). This
83/// places the std::c* I/O streams into one .cpp file and relieves the whole
84/// program from having to have hundreds of static c'tor/d'tors for them.
85///
86llvm_ostream getErrorOutputStream(const char *DebugType);
87
88#ifdef NDEBUG
89#define DOUT llvm_ostream()
90#else
91#define DOUT getErrorOutputStream(DEBUG_TYPE)
92#endif
93
94} // End llvm namespace
95
96#endif
97