include/llvm/Support/Debug.h

   1 //===- llvm/Support/Debug.h - Easy way to add debug output ------*- C++ -*-===//
   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 // LLVM_DEBUG() requires the DEBUG_TYPE macro to be defined. Set it to "foo"
  16 // specify that your debug code belongs to class "foo". Be careful that you only
  17 // do this after including Debug.h and not around any #include of headers.
  18 // Headers should define and undef the macro acround the code that needs to use
  19 // the LLVM_DEBUG() macro. Then, on the command line, you can specify
  20 // '-debug-only=foo' to enable JUST the debug information for the foo class.
  21 //
  22 // When compiling without assertions, the -debug-* options and all code in
  23 // LLVM_DEBUG() statements disappears, so it does not affect the runtime of the
  24 // code.
  25 //
  26 //===----------------------------------------------------------------------===//
  27
  28 #ifndef LLVM_SUPPORT_DEBUG_H
  29 #define LLVM_SUPPORT_DEBUG_H
  30
  31 namespace llvm {
  32
  33 class raw_ostream;
  34
  35 #ifndef NDEBUG
  36
  37 /// isCurrentDebugType - Return true if the specified string is the debug type
  38 /// specified on the command line, or if none was specified on the command line
  39 /// with the -debug-only=X option.
  40 ///
  41 bool isCurrentDebugType(const char *Type);
  42
  43 /// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
  44 /// option were specified.  Note that DebugFlag also needs to be set to true for
  45 /// debug output to be produced.
  46 ///
  47 void setCurrentDebugType(const char *Type);
  48
  49 /// setCurrentDebugTypes - Set the current debug type, as if the
  50 /// -debug-only=X,Y,Z option were specified. Note that DebugFlag
  51 /// also needs to be set to true for debug output to be produced.
  52 ///
  53 void setCurrentDebugTypes(const char **Types, unsigned Count);
  54
  55 /// DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug
  56 /// information.  In the '-debug' option is specified on the commandline, and if
  57 /// this is a debug build, then the code specified as the option to the macro
  58 /// will be executed.  Otherwise it will not be.  Example:
  59 ///
  60 /// DEBUG_WITH_TYPE("bitset", dbgs() << "Bitset contains: " << Bitset << "\n");
  61 ///
  62 /// This will emit the debug information if -debug is present, and -debug-only
  63 /// is not specified, or is specified as "bitset".
  64 #define DEBUG_WITH_TYPE(TYPE, X)                                        \
  65   do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { X; } \
  66   } while (false)
  67
  68 #else
  69 #define isCurrentDebugType(X) (false)
  70 #define setCurrentDebugType(X)
  71 #define setCurrentDebugTypes(X, N)
  72 #define DEBUG_WITH_TYPE(TYPE, X) do { } while (false)
  73 #endif
  74
  75 /// This boolean is set to true if the '-debug' command line option
  76 /// is specified.  This should probably not be referenced directly, instead, use
  77 /// the DEBUG macro below.
  78 ///
  79 extern bool DebugFlag;
  80
  81 /// \name Verification flags.
  82 ///
  83 /// These flags turns on/off that are expensive and are turned off by default,
  84 /// unless macro EXPENSIVE_CHECKS is defined. The flags allow selectively
  85 /// turning the checks on without need to recompile.
  86 /// \{
  87
  88 /// Enables verification of dominator trees.
  89 ///
  90 extern bool VerifyDomInfo;
  91
  92 /// Enables verification of loop info.
  93 ///
  94 extern bool VerifyLoopInfo;
  95
  96 /// Enables verification of MemorySSA.
  97 ///
  98 extern bool VerifyMemorySSA;
  99
 100 ///\}
 101
 102 /// EnableDebugBuffering - This defaults to false.  If true, the debug
 103 /// stream will install signal handlers to dump any buffered debug
 104 /// output.  It allows clients to selectively allow the debug stream
 105 /// to install signal handlers if they are certain there will be no
 106 /// conflict.
 107 ///
 108 extern bool EnableDebugBuffering;
 109
 110 /// dbgs() - This returns a reference to a raw_ostream for debugging
 111 /// messages.  If debugging is disabled it returns errs().  Use it
 112 /// like: dbgs() << "foo" << "bar";
 113 raw_ostream &dbgs();
 114
 115 // DEBUG macro - This macro should be used by passes to emit debug information.
 116 // In the '-debug' option is specified on the commandline, and if this is a
 117 // debug build, then the code specified as the option to the macro will be
 118 // executed.  Otherwise it will not be.  Example:
 119 //
 120 // LLVM_DEBUG(dbgs() << "Bitset contains: " << Bitset << "\n");
 121 //
 122 #define LLVM_DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X)
 123
 124 } // end namespace llvm
 125
 126 #endif // LLVM_SUPPORT_DEBUG_H