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/ManagedStatic.h"
29 #include "llvm/Support/Signals.h"
30 #include "llvm/Support/circular_raw_ostream.h"
31
32 #include <vector>
33
34 #undef isCurrentDebugType
35 #undef setCurrentDebugType
36
37 using namespace llvm;
38
39 // Even though LLVM might be built with NDEBUG, define symbols that the code
40 // built without NDEBUG can depend on via the llvm/Support/Debug.h header.
41 namespace llvm {
42 /// Exported boolean set by the -debug option.
43 bool DebugFlag = false;
44
45 static ManagedStatic<std::vector<std::string>> CurrentDebugType;
46
47 /// Return true if the specified string is the debug type
48 /// specified on the command line, or if none was specified on the command line
49 /// with the -debug-only=X option.
isCurrentDebugType(const char * DebugType)50 bool isCurrentDebugType(const char *DebugType) {
51 if (CurrentDebugType->empty())
52 return true;
53 // see if DebugType is in list. Note: do not use find() as that forces us to
54 // unnecessarily create an std::string instance.
55 for (auto d : *CurrentDebugType) {
56 if (d == DebugType)
57 return true;
58 }
59 return false;
60 }
61
62 /// Set the current debug type, as if the -debug-only=X
63 /// option were specified. Note that DebugFlag also needs to be set to true for
64 /// debug output to be produced.
65 ///
setCurrentDebugType(const char * Type)66 void setCurrentDebugType(const char *Type) {
67 CurrentDebugType->clear();
68 CurrentDebugType->push_back(Type);
69 }
70
71 } // namespace llvm
72
73 // All Debug.h functionality is a no-op in NDEBUG mode.
74 #ifndef NDEBUG
75
76 // -debug - Command line option to enable the DEBUG statements in the passes.
77 // This flag may only be enabled in debug builds.
78 //static bool Debug = false;
79
80 // -debug-buffer-size - Buffer the last N characters of debug output
81 //until program termination.
82 static unsigned DebugBufferSize = 0;
83
84 namespace {
85
86 struct DebugOnlyOpt {
operator =__anon1de3744f0111::DebugOnlyOpt87 void operator=(const std::string &Val) const {
88 if (Val.empty())
89 return;
90 DebugFlag = true;
91 CurrentDebugType->push_back(Val);
92 }
93 };
94
95 }
96
97 //static DebugOnlyOpt DebugOnlyOptLoc;
98
99 //static DebugOnlyOpt DebugOnly;
100
101 // Signal handlers - dump debug output on termination.
debug_user_sig_handler(void * Cookie)102 static void debug_user_sig_handler(void *Cookie) {
103 // This is a bit sneaky. Since this is under #ifndef NDEBUG, we
104 // know that debug mode is enabled and dbgs() really is a
105 // circular_raw_ostream. If NDEBUG is defined, then dbgs() ==
106 // errs() but this will never be invoked.
107 llvm::circular_raw_ostream *dbgout =
108 static_cast<llvm::circular_raw_ostream *>(&llvm::dbgs());
109 dbgout->flushBufferWithBanner();
110 }
111
112 /// dbgs - Return a circular-buffered debug stream.
dbgs()113 raw_ostream &llvm::dbgs() {
114 // Do one-time initialization in a thread-safe way.
115 static struct dbgstream {
116 circular_raw_ostream strm;
117
118 dbgstream() :
119 strm(errs(), "*** Debug Log Output ***\n",
120 (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) {
121 if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)
122 // TODO: Add a handler for SIGUSER1-type signals so the user can
123 // force a debug dump.
124 sys::AddSignalHandler(&debug_user_sig_handler, nullptr);
125 // Otherwise we've already set the debug stream buffer size to
126 // zero, disabling buffering so it will output directly to errs().
127 }
128 } thestrm;
129
130 return thestrm.strm;
131 }
132
133 #else
134 // Avoid "has no symbols" warning.
135 namespace llvm {
136 /// dbgs - Return errs().
dbgs()137 raw_ostream &dbgs() {
138 return errs();
139 }
140 }
141
142 #endif
143
144 /// EnableDebugBuffering - Turn on signal handler installation.
145 ///
146 bool llvm::EnableDebugBuffering = false;
147