LLVM 17.0.0git
Debug.cpp
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1//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements a handy way of adding debugging information to your
10// code, without it being enabled all of the time, and without having to add
11// command line options to enable it.
12//
13// In particular, just wrap your code with the LLVM_DEBUG() macro, and it will
14// be enabled automatically if you specify '-debug' on the command-line.
15// Alternatively, you can also use the SET_DEBUG_TYPE("foo") macro to specify
16// that your debug code belongs to class "foo". Then, on the command line, you
17// can specify '-debug-only=foo' to enable JUST the debug information for the
18// foo class.
19//
20// When compiling without assertions, the -debug-* options and all code in
21// LLVM_DEBUG() statements disappears, so it does not affect the runtime of the
22// code.
23//
24//===----------------------------------------------------------------------===//
25
26#include "llvm/Support/Debug.h"
32
33#include "DebugOptions.h"
34
35#undef isCurrentDebugType
36#undef setCurrentDebugType
37#undef setCurrentDebugTypes
38
39using namespace llvm;
40
41// Even though LLVM might be built with NDEBUG, define symbols that the code
42// built without NDEBUG can depend on via the llvm/Support/Debug.h header.
43namespace llvm {
44/// Exported boolean set by the -debug option.
45bool DebugFlag = false;
46
48
49/// Return true if the specified string is the debug type
50/// specified on the command line, or if none was specified on the command line
51/// with the -debug-only=X option.
52bool isCurrentDebugType(const char *DebugType) {
53 if (CurrentDebugType->empty())
54 return true;
55 // See if DebugType is in list. Note: do not use find() as that forces us to
56 // unnecessarily create an std::string instance.
57 for (auto &d : *CurrentDebugType) {
58 if (d == DebugType)
59 return true;
60 }
61 return false;
62}
63
64/// Set the current debug type, as if the -debug-only=X
65/// option were specified. Note that DebugFlag also needs to be set to true for
66/// debug output to be produced.
67///
68void setCurrentDebugTypes(const char **Types, unsigned Count);
69
70void setCurrentDebugType(const char *Type) {
72}
73
74void setCurrentDebugTypes(const char **Types, unsigned Count) {
75 CurrentDebugType->clear();
76 for (size_t T = 0; T < Count; ++T)
77 CurrentDebugType->push_back(Types[T]);
78}
79} // namespace llvm
80
81// All Debug.h functionality is a no-op in NDEBUG mode.
82#ifndef NDEBUG
83
84namespace {
85struct CreateDebug {
86 static void *call() {
87 return new cl::opt<bool, true>("debug", cl::desc("Enable debug output"),
89 }
90};
91
92// -debug-buffer-size - Buffer the last N characters of debug output
93//until program termination.
94struct CreateDebugBufferSize {
95 static void *call() {
96 return new cl::opt<unsigned>(
97 "debug-buffer-size",
98 cl::desc("Buffer the last N characters of debug output "
99 "until program termination. "
100 "[default 0 -- immediate print-out]"),
101 cl::Hidden, cl::init(0));
102 }
103};
104} // namespace
105
106// -debug - Command line option to enable the DEBUG statements in the passes.
107// This flag may only be enabled in debug builds.
110
111namespace {
112
113struct DebugOnlyOpt {
114 void operator=(const std::string &Val) const {
115 if (Val.empty())
116 return;
117 DebugFlag = true;
119 StringRef(Val).split(dbgTypes, ',', -1, false);
120 for (auto dbgType : dbgTypes)
121 CurrentDebugType->push_back(std::string(dbgType));
122 }
123};
124} // namespace
125
126static DebugOnlyOpt DebugOnlyOptLoc;
127
128namespace {
129struct CreateDebugOnly {
130 static void *call() {
132 "debug-only",
133 cl::desc("Enable a specific type of debug output (comma separated list "
134 "of types)"),
135 cl::Hidden, cl::value_desc("debug string"),
137 }
138};
139} // namespace
140
142 CreateDebugOnly>
144
146 *Debug;
148 *DebugOnly;
149}
150
151// Signal handlers - dump debug output on termination.
152static void debug_user_sig_handler(void *Cookie) {
153 // This is a bit sneaky. Since this is under #ifndef NDEBUG, we
154 // know that debug mode is enabled and dbgs() really is a
155 // circular_raw_ostream. If NDEBUG is defined, then dbgs() ==
156 // errs() but this will never be invoked.
158 static_cast<circular_raw_ostream &>(llvm::dbgs());
159 dbgout.flushBufferWithBanner();
160}
161
162/// dbgs - Return a circular-buffered debug stream.
164 // Do one-time initialization in a thread-safe way.
165 static struct dbgstream {
167
168 dbgstream()
169 : strm(errs(), "*** Debug Log Output ***\n",
172 // TODO: Add a handler for SIGUSER1-type signals so the user can
173 // force a debug dump.
175 // Otherwise we've already set the debug stream buffer size to
176 // zero, disabling buffering so it will output directly to errs().
177 }
178 } thestrm;
179
180 return thestrm.strm;
181}
182
183#else
184// Avoid "has no symbols" warning.
185namespace llvm {
186 /// dbgs - Return errs().
187 raw_ostream &dbgs() {
188 return errs();
189 }
190}
192#endif
193
194/// EnableDebugBuffering - Turn on signal handler installation.
195///
static ManagedStatic< cl::opt< bool, true >, CreateDebug > Debug
Definition: Debug.cpp:108
static void debug_user_sig_handler(void *Cookie)
Definition: Debug.cpp:152
static ManagedStatic< cl::opt< unsigned >, CreateDebugBufferSize > DebugBufferSize
Definition: Debug.cpp:109
static ManagedStatic< cl::opt< DebugOnlyOpt, true, cl::parser< std::string > >, CreateDebugOnly > DebugOnly
Definition: Debug.cpp:143
static DebugOnlyOpt DebugOnlyOptLoc
Definition: Debug.cpp:126
ManagedStatic - This transparently changes the behavior of global statics to be lazily constructed on...
Definition: ManagedStatic.h:83
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1200
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
std::pair< StringRef, StringRef > split(char Separator) const
Split into two substrings around the first occurrence of a separator character.
Definition: StringRef.h:688
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
circular_raw_ostream - A raw_ostream which can save its data to a circular buffer,...
void flushBufferWithBanner()
flushBufferWithBanner - Force output of the buffer along with a small header.
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
@ ValueRequired
Definition: CommandLine.h:132
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:445
LocationClass< Ty > location(Ty &L)
Definition: CommandLine.h:465
void AddSignalHandler(SignalHandlerCallback FnPtr, void *Cookie)
Add a function to be called when an abort/kill signal is delivered to the process.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
bool EnableDebugBuffering
EnableDebugBuffering - This defaults to false.
Definition: Debug.cpp:196
void initDebugOptions()
Definition: Debug.cpp:145
bool DebugFlag
This boolean is set to true if the '-debug' command line option is specified.
Definition: Debug.cpp:45
void setCurrentDebugTypes(const char **Types, unsigned Count)
setCurrentDebugTypes - Set the current debug type, as if the -debug-only=X,Y,Z option were specified.
Definition: Debug.cpp:74
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
void setCurrentDebugType(const char *Type)
setCurrentDebugType - Set the current debug type, as if the -debug-only=X option were specified.
Definition: Debug.cpp:70
raw_fd_ostream & errs()
This returns a reference to a raw_ostream for standard error.
bool isCurrentDebugType(const char *Type)
isCurrentDebugType - Return true if the specified string is the debug type specified on the command l...
Definition: Debug.cpp:52
static ManagedStatic< std::vector< std::string > > CurrentDebugType
Definition: Debug.cpp:47