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// DEBUG() requires the DEBUG_TYPE macro to be defined. Set it to "foo" specify
17// that your debug code belongs to class "foo". Be careful that you only do
18// this after including Debug.h and not around any #include of headers. Headers
19// should define and undef the macro acround the code that needs to use the
20// DEBUG() macro. Then, on the command line, you can specify '-debug-only=foo'
21// to enable JUST the debug information for the foo class.
22//
23// When compiling without assertions, the -debug-* options and all code in
24// DEBUG() statements disappears, so it does not affect the runtime of the code.
25//
26//===----------------------------------------------------------------------===//
27
28#ifndef LLVM_SUPPORT_DEBUG_H
29#define LLVM_SUPPORT_DEBUG_H
30
31namespace llvm {
32class raw_ostream;
33
34#ifndef NDEBUG
35/// DebugFlag - This boolean is set to true if the '-debug' command line option
36/// is specified.  This should probably not be referenced directly, instead, use
37/// the DEBUG macro below.
38///
39extern bool DebugFlag;
40
41/// isCurrentDebugType - Return true if the specified string is the debug type
42/// specified on the command line, or if none was specified on the command line
43/// with the -debug-only=X option.
44///
45bool isCurrentDebugType(const char *Type);
46
47/// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
48/// option were specified.  Note that DebugFlag also needs to be set to true for
49/// debug output to be produced.
50///
51void setCurrentDebugType(const char *Type);
52
53/// DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug
54/// information.  In the '-debug' option is specified on the commandline, and if
55/// this is a debug build, then the code specified as the option to the macro
56/// will be executed.  Otherwise it will not be.  Example:
57///
58/// DEBUG_WITH_TYPE("bitset", dbgs() << "Bitset contains: " << Bitset << "\n");
59///
60/// This will emit the debug information if -debug is present, and -debug-only
61/// is not specified, or is specified as "bitset".
62#define DEBUG_WITH_TYPE(TYPE, X)                                        \
63  do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { X; } \
64  } while (0)
65
66#else
67#define isCurrentDebugType(X) (false)
68#define setCurrentDebugType(X)
69#define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
70#endif
71
72/// EnableDebugBuffering - This defaults to false.  If true, the debug
73/// stream will install signal handlers to dump any buffered debug
74/// output.  It allows clients to selectively allow the debug stream
75/// to install signal handlers if they are certain there will be no
76/// conflict.
77///
78extern bool EnableDebugBuffering;
79
80/// dbgs() - This returns a reference to a raw_ostream for debugging
81/// messages.  If debugging is disabled it returns errs().  Use it
82/// like: dbgs() << "foo" << "bar";
83raw_ostream &dbgs();
84
85// DEBUG macro - This macro should be used by passes to emit debug information.
86// In the '-debug' option is specified on the commandline, and if this is a
87// debug build, then the code specified as the option to the macro will be
88// executed.  Otherwise it will not be.  Example:
89//
90// DEBUG(dbgs() << "Bitset contains: " << Bitset << "\n");
91//
92#define DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X)
93
94} // End llvm namespace
95
96#endif
97