Debug.cpp revision 198892 
1//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
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 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#include "llvm/Support/CommandLine.h"
27#include "llvm/Support/Debug.h"
28using namespace llvm;
29
30// All Debug.h functionality is a no-op in NDEBUG mode.
31#ifndef NDEBUG
32bool llvm::DebugFlag;  // DebugFlag - Exported boolean set by the -debug option
33
34// -debug - Command line option to enable the DEBUG statements in the passes.
35// This flag may only be enabled in debug builds.
36static cl::opt<bool, true>
37Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
38      cl::location(DebugFlag));
39
40static std::string CurrentDebugType;
41static struct DebugOnlyOpt {
42  void operator=(const std::string &Val) const {
43    DebugFlag |= !Val.empty();
44    CurrentDebugType = Val;
45  }
46} DebugOnlyOptLoc;
47
48static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
49DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
50          cl::Hidden, cl::value_desc("debug string"),
51          cl::location(DebugOnlyOptLoc), cl::ValueRequired);
52
53// isCurrentDebugType - Return true if the specified string is the debug type
54// specified on the command line, or if none was specified on the command line
55// with the -debug-only=X option.
56//
57bool llvm::isCurrentDebugType(const char *DebugType) {
58  return CurrentDebugType.empty() || DebugType == CurrentDebugType;
59}
60
61/// SetCurrentDebugType - Set the current debug type, as if the -debug-only=X
62/// option were specified.  Note that DebugFlag also needs to be set to true for
63/// debug output to be produced.
64///
65void SetCurrentDebugType(const char *Type) {
66  CurrentDebugType = Type;
67}
68
69#else
70// Avoid "has no symbols" warning.
71namespace llvm {
72int Debug_dummy = 0;
73}
74#endif
75