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comparison lib/Support/Debug.cpp @ 0:95c75e76d11b LLVM3.4

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LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
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children 54457678186b
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-1:000000000000 0:95c75e76d11b
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
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Signals.h"
29 #include "llvm/Support/circular_raw_ostream.h"
30
31 using namespace llvm;
32
33 // All Debug.h functionality is a no-op in NDEBUG mode.
34 #ifndef NDEBUG
35 bool llvm::DebugFlag; // DebugFlag - Exported boolean set by the -debug option
36
37 // -debug - Command line option to enable the DEBUG statements in the passes.
38 // This flag may only be enabled in debug builds.
39 static cl::opt<bool, true>
40 Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
41 cl::location(DebugFlag));
42
43 // -debug-buffer-size - Buffer the last N characters of debug output
44 //until program termination.
45 static cl::opt<unsigned>
46 DebugBufferSize("debug-buffer-size",
47 cl::desc("Buffer the last N characters of debug output "
48 "until program termination. "
49 "[default 0 -- immediate print-out]"),
50 cl::Hidden,
51 cl::init(0));
52
53 static std::string CurrentDebugType;
54
55 namespace {
56
57 struct DebugOnlyOpt {
58 void operator=(const std::string &Val) const {
59 DebugFlag |= !Val.empty();
60 CurrentDebugType = Val;
61 }
62 };
63
64 }
65
66 static DebugOnlyOpt DebugOnlyOptLoc;
67
68 static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
69 DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
70 cl::Hidden, cl::value_desc("debug string"),
71 cl::location(DebugOnlyOptLoc), cl::ValueRequired);
72
73 // Signal handlers - dump debug output on termination.
74 static void debug_user_sig_handler(void *Cookie) {
75 // This is a bit sneaky. Since this is under #ifndef NDEBUG, we
76 // know that debug mode is enabled and dbgs() really is a
77 // circular_raw_ostream. If NDEBUG is defined, then dbgs() ==
78 // errs() but this will never be invoked.
79 llvm::circular_raw_ostream *dbgout =
80 static_cast<llvm::circular_raw_ostream *>(&llvm::dbgs());
81 dbgout->flushBufferWithBanner();
82 }
83
84 // isCurrentDebugType - Return true if the specified string is the debug type
85 // specified on the command line, or if none was specified on the command line
86 // with the -debug-only=X option.
87 //
88 bool llvm::isCurrentDebugType(const char *DebugType) {
89 return CurrentDebugType.empty() || DebugType == CurrentDebugType;
90 }
91
92 /// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
93 /// option were specified. Note that DebugFlag also needs to be set to true for
94 /// debug output to be produced.
95 ///
96 void llvm::setCurrentDebugType(const char *Type) {
97 CurrentDebugType = Type;
98 }
99
100 /// dbgs - Return a circular-buffered debug stream.
101 raw_ostream &llvm::dbgs() {
102 // Do one-time initialization in a thread-safe way.
103 static struct dbgstream {
104 circular_raw_ostream strm;
105
106 dbgstream() :
107 strm(errs(), "*** Debug Log Output ***\n",
108 (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) {
109 if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)
110 // TODO: Add a handler for SIGUSER1-type signals so the user can
111 // force a debug dump.
112 sys::AddSignalHandler(&debug_user_sig_handler, 0);
113 // Otherwise we've already set the debug stream buffer size to
114 // zero, disabling buffering so it will output directly to errs().
115 }
116 } thestrm;
117
118 return thestrm.strm;
119 }
120
121 #else
122 // Avoid "has no symbols" warning.
123 namespace llvm {
124 /// dbgs - Return errs().
125 raw_ostream &dbgs() {
126 return errs();
127 }
128 }
129
130 #endif
131
132 /// EnableDebugBuffering - Turn on signal handler installation.
133 ///
134 bool llvm::EnableDebugBuffering = false;