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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 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 affect the runtime of the code. | |
23 | // | |
24 | //===----------------------------------------------------------------------===// | |
25 | ||
223e47cc | 26 | #include "llvm/Support/Debug.h" |
970d7e83 | 27 | #include "llvm/Support/CommandLine.h" |
223e47cc | 28 | #include "llvm/Support/Signals.h" |
970d7e83 | 29 | #include "llvm/Support/circular_raw_ostream.h" |
1a4d82fc | 30 | #include "llvm/Support/ManagedStatic.h" |
223e47cc LB |
31 | |
32 | using namespace llvm; | |
33 | ||
34 | // All Debug.h functionality is a no-op in NDEBUG mode. | |
35 | #ifndef NDEBUG | |
36 | bool llvm::DebugFlag; // DebugFlag - Exported boolean set by the -debug option | |
37 | ||
38 | // -debug - Command line option to enable the DEBUG statements in the passes. | |
39 | // This flag may only be enabled in debug builds. | |
40 | static cl::opt<bool, true> | |
41 | Debug("debug", cl::desc("Enable debug output"), cl::Hidden, | |
42 | cl::location(DebugFlag)); | |
43 | ||
44 | // -debug-buffer-size - Buffer the last N characters of debug output | |
45 | //until program termination. | |
46 | static cl::opt<unsigned> | |
47 | DebugBufferSize("debug-buffer-size", | |
970d7e83 | 48 | cl::desc("Buffer the last N characters of debug output " |
223e47cc LB |
49 | "until program termination. " |
50 | "[default 0 -- immediate print-out]"), | |
51 | cl::Hidden, | |
52 | cl::init(0)); | |
53 | ||
1a4d82fc | 54 | static ManagedStatic<std::string> CurrentDebugType; |
223e47cc LB |
55 | |
56 | namespace { | |
57 | ||
58 | struct DebugOnlyOpt { | |
59 | void operator=(const std::string &Val) const { | |
60 | DebugFlag |= !Val.empty(); | |
1a4d82fc | 61 | *CurrentDebugType = Val; |
223e47cc LB |
62 | } |
63 | }; | |
64 | ||
65 | } | |
66 | ||
67 | static DebugOnlyOpt DebugOnlyOptLoc; | |
68 | ||
69 | static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> > | |
70 | DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"), | |
71 | cl::Hidden, cl::value_desc("debug string"), | |
72 | cl::location(DebugOnlyOptLoc), cl::ValueRequired); | |
73 | ||
74 | // Signal handlers - dump debug output on termination. | |
75 | static void debug_user_sig_handler(void *Cookie) { | |
76 | // This is a bit sneaky. Since this is under #ifndef NDEBUG, we | |
77 | // know that debug mode is enabled and dbgs() really is a | |
78 | // circular_raw_ostream. If NDEBUG is defined, then dbgs() == | |
79 | // errs() but this will never be invoked. | |
80 | llvm::circular_raw_ostream *dbgout = | |
81 | static_cast<llvm::circular_raw_ostream *>(&llvm::dbgs()); | |
82 | dbgout->flushBufferWithBanner(); | |
83 | } | |
84 | ||
85 | // isCurrentDebugType - Return true if the specified string is the debug type | |
86 | // specified on the command line, or if none was specified on the command line | |
87 | // with the -debug-only=X option. | |
88 | // | |
89 | bool llvm::isCurrentDebugType(const char *DebugType) { | |
1a4d82fc | 90 | return CurrentDebugType->empty() || DebugType == *CurrentDebugType; |
223e47cc LB |
91 | } |
92 | ||
93 | /// setCurrentDebugType - Set the current debug type, as if the -debug-only=X | |
94 | /// option were specified. Note that DebugFlag also needs to be set to true for | |
95 | /// debug output to be produced. | |
96 | /// | |
97 | void llvm::setCurrentDebugType(const char *Type) { | |
1a4d82fc | 98 | *CurrentDebugType = Type; |
223e47cc LB |
99 | } |
100 | ||
101 | /// dbgs - Return a circular-buffered debug stream. | |
102 | raw_ostream &llvm::dbgs() { | |
103 | // Do one-time initialization in a thread-safe way. | |
104 | static struct dbgstream { | |
105 | circular_raw_ostream strm; | |
106 | ||
107 | dbgstream() : | |
108 | strm(errs(), "*** Debug Log Output ***\n", | |
109 | (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) { | |
110 | if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0) | |
111 | // TODO: Add a handler for SIGUSER1-type signals so the user can | |
112 | // force a debug dump. | |
1a4d82fc | 113 | sys::AddSignalHandler(&debug_user_sig_handler, nullptr); |
223e47cc LB |
114 | // Otherwise we've already set the debug stream buffer size to |
115 | // zero, disabling buffering so it will output directly to errs(). | |
116 | } | |
117 | } thestrm; | |
118 | ||
119 | return thestrm.strm; | |
120 | } | |
121 | ||
122 | #else | |
123 | // Avoid "has no symbols" warning. | |
124 | namespace llvm { | |
125 | /// dbgs - Return errs(). | |
126 | raw_ostream &dbgs() { | |
127 | return errs(); | |
128 | } | |
129 | } | |
130 | ||
131 | #endif | |
132 | ||
133 | /// EnableDebugBuffering - Turn on signal handler installation. | |
134 | /// | |
135 | bool llvm::EnableDebugBuffering = false; |