Debug.h revision c3c9239d76e2acb01dac8c72323a0b28fadebe4b 
1//===- llvm/Support/Debug.h - Easy way to add debug output ------*- 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// This file implements a handy 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 without assertions, the -debug-* options and all code in
22// DEBUG() 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 "llvm/Support/Streams.h"
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_WITH_TYPE macro - This macro should be used by passes to emit debug
46// information.  In the '-debug' option is specified on the commandline, and if
47// this is a debug build, then the code specified as the option to the macro
48// will be executed.  Otherwise it will not be.  Example:
49//
50// DEBUG_WITH_TYPE("bitset", errs() << "Bitset contains: " << Bitset << "\n");
51//
52// This will emit the debug information if -debug is present, and -debug-only is
53// not specified, or is specified as "bitset".
54
55#ifdef NDEBUG
56#define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
57#else
58#define DEBUG_WITH_TYPE(TYPE, X)                                        \
59  do { if (DebugFlag && isCurrentDebugType(TYPE)) { X; } } while (0)
60#endif
61
62// DEBUG macro - This macro should be used by passes to emit debug information.
63// In the '-debug' option is specified on the commandline, and if this is a
64// debug build, then the code specified as the option to the macro will be
65// executed.  Otherwise it will not be.  Example:
66//
67// DEBUG(errs() << "Bitset contains: " << Bitset << "\n");
68//
69
70#ifndef DEBUG_TYPE
71#define DEBUG_TYPE ""
72#endif
73
74#define DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X)
75
76/// getNullOutputStream - Return a null string that does not output
77/// anything.  This hides the static variable from other modules.
78///
79OStream &getNullOutputStream();
80
81/// getErrorOutputStream - Returns the error output stream (std::cerr). This
82/// places the std::c* I/O streams into one .cpp file and relieves the whole
83/// program from having to have hundreds of static c'tor/d'tors for them.
84///
85OStream &getErrorOutputStream(const char *DebugType);
86
87#ifdef NDEBUG
88#define DOUT llvm::getNullOutputStream()
89#else
90#define DOUT llvm::getErrorOutputStream(DEBUG_TYPE)
91#endif
92
93} // End llvm namespace
94
95#endif
96