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Chris Lattner038e05a2003-08-01 22:15:41 +00001//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
Misha Brukmanf976c852005-04-21 22:55:34 +00002//
John Criswellb576c942003-10-20 19:43:21 +00003// The LLVM Compiler Infrastructure
4//
Chris Lattner4ee451d2007-12-29 20:36:04 +00005// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
Misha Brukmanf976c852005-04-21 22:55:34 +00007//
John Criswellb576c942003-10-20 19:43:21 +00008//===----------------------------------------------------------------------===//
Chris Lattner038e05a2003-08-01 22:15:41 +00009//
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
Reid Spencer551ccae2004-09-01 22:55:40 +000026#include "llvm/Support/CommandLine.h"
Bill Wendlingab41c3e2006-11-17 09:54:47 +000027#include "llvm/Support/Debug.h"
David Greeneb5d568c2009-12-23 16:39:06 +000028#include "llvm/Support/circular_raw_ostream.h"
29#include "llvm/System/Signals.h"
30
Chris Lattner2cdd21c2003-12-14 21:35:53 +000031using namespace llvm;
Chris Lattner038e05a2003-08-01 22:15:41 +000032
Daniel Dunbar43ed2672009-08-23 08:50:52 +000033// All Debug.h functionality is a no-op in NDEBUG mode.
34#ifndef NDEBUG
Chris Lattner2cdd21c2003-12-14 21:35:53 +000035bool llvm::DebugFlag; // DebugFlag - Exported boolean set by the -debug option
Chris Lattner038e05a2003-08-01 22:15:41 +000036
Chris Lattnera36b81d2009-08-23 07:05:39 +000037// -debug - Command line option to enable the DEBUG statements in the passes.
38// This flag may only be enabled in debug builds.
39static cl::opt<bool, true>
40Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
41 cl::location(DebugFlag));
Chris Lattner038e05a2003-08-01 22:15:41 +000042
David Greeneb5d568c2009-12-23 16:39:06 +000043// -debug-buffer-size - Buffer the last N characters of debug output
44//until program termination.
45static cl::opt<unsigned>
46DebugBufferSize("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
Chris Lattnera36b81d2009-08-23 07:05:39 +000053static std::string CurrentDebugType;
Dan Gohmanb3579832010-04-15 17:08:50 +000054
55namespace {
56
57struct DebugOnlyOpt {
Chris Lattnera36b81d2009-08-23 07:05:39 +000058 void operator=(const std::string &Val) const {
59 DebugFlag |= !Val.empty();
60 CurrentDebugType = Val;
61 }
Dan Gohmanb3579832010-04-15 17:08:50 +000062};
63
64}
65
66static DebugOnlyOpt DebugOnlyOptLoc;
Chris Lattner038e05a2003-08-01 22:15:41 +000067
Chris Lattnera36b81d2009-08-23 07:05:39 +000068static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
69DebugOnly("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);
Chris Lattner038e05a2003-08-01 22:15:41 +000072
David Greeneb5d568c2009-12-23 16:39:06 +000073// Signal handlers - dump debug output on termination.
Dan Gohman16e02092010-03-24 19:38:02 +000074static void debug_user_sig_handler(void *Cookie) {
David Greeneb5d568c2009-12-23 16:39:06 +000075 // 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
Chris Lattner038e05a2003-08-01 22:15:41 +000084// 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//
Chris Lattner2cdd21c2003-12-14 21:35:53 +000088bool llvm::isCurrentDebugType(const char *DebugType) {
Chris Lattner038e05a2003-08-01 22:15:41 +000089 return CurrentDebugType.empty() || DebugType == CurrentDebugType;
Chris Lattner038e05a2003-08-01 22:15:41 +000090}
Chris Lattner70197a32009-10-28 15:32:19 +000091
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///
Xerxes Ranby5aa638d2009-11-09 14:50:34 +000096void llvm::SetCurrentDebugType(const char *Type) {
Chris Lattner70197a32009-10-28 15:32:19 +000097 CurrentDebugType = Type;
98}
99
David Greeneb5d568c2009-12-23 16:39:06 +0000100/// dbgs - Return a circular-buffered debug stream.
101raw_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
David Greene03776422009-12-23 23:23:15 +0000114 // zero, disabling buffering so it will output directly to errs().
David Greeneb5d568c2009-12-23 16:39:06 +0000115 }
116 } thestrm;
117
118 return thestrm.strm;
119}
120
Daniel Dunbar43ed2672009-08-23 08:50:52 +0000121#else
122// Avoid "has no symbols" warning.
Chris Lattner70197a32009-10-28 15:32:19 +0000123namespace llvm {
David Greene2ef951e2010-01-20 15:27:19 +0000124 /// dbgs - Return errs().
David Greeneb5d568c2009-12-23 16:39:06 +0000125 raw_ostream &dbgs() {
David Greene2ef951e2010-01-20 15:27:19 +0000126 return errs();
David Greeneb5d568c2009-12-23 16:39:06 +0000127 }
Chris Lattner70197a32009-10-28 15:32:19 +0000128}
David Greeneb5d568c2009-12-23 16:39:06 +0000129
Daniel Dunbar43ed2672009-08-23 08:50:52 +0000130#endif
David Greeneb5d568c2009-12-23 16:39:06 +0000131
132/// EnableDebugBuffering - Turn on signal handler installation.
133///
134bool llvm::EnableDebugBuffering = false;