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      1 //===- llvm/Support/Debug.h - Easy way to add debug output ------*- C++ -*-===//
      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 effect the runtime of the code.
     23 //
     24 //===----------------------------------------------------------------------===//
     25 
     26 #ifndef LLVM_SUPPORT_DEBUG_H
     27 #define LLVM_SUPPORT_DEBUG_H
     28 
     29 namespace llvm {
     30 
     31 class raw_ostream;
     32 
     33 /// DEBUG_TYPE macro - Files can specify a DEBUG_TYPE as a string, which causes
     34 /// all of their DEBUG statements to be activatable with -debug-only=thatstring.
     35 #ifndef DEBUG_TYPE
     36 #define DEBUG_TYPE ""
     37 #endif
     38 
     39 #ifndef NDEBUG
     40 /// DebugFlag - This boolean is set to true if the '-debug' command line option
     41 /// is specified.  This should probably not be referenced directly, instead, use
     42 /// the DEBUG macro below.
     43 ///
     44 extern bool DebugFlag;
     45 
     46 /// isCurrentDebugType - Return true if the specified string is the debug type
     47 /// specified on the command line, or if none was specified on the command line
     48 /// with the -debug-only=X option.
     49 ///
     50 bool isCurrentDebugType(const char *Type);
     51 
     52 /// SetCurrentDebugType - Set the current debug type, as if the -debug-only=X
     53 /// option were specified.  Note that DebugFlag also needs to be set to true for
     54 /// debug output to be produced.
     55 ///
     56 void SetCurrentDebugType(const char *Type);
     57 
     58 /// DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug
     59 /// information.  In the '-debug' option is specified on the commandline, and if
     60 /// this is a debug build, then the code specified as the option to the macro
     61 /// will be executed.  Otherwise it will not be.  Example:
     62 ///
     63 /// DEBUG_WITH_TYPE("bitset", dbgs() << "Bitset contains: " << Bitset << "\n");
     64 ///
     65 /// This will emit the debug information if -debug is present, and -debug-only
     66 /// is not specified, or is specified as "bitset".
     67 #define DEBUG_WITH_TYPE(TYPE, X)                                        \
     68   do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { X; } \
     69   } while (0)
     70 
     71 #else
     72 #define isCurrentDebugType(X) (false)
     73 #define SetCurrentDebugType(X)
     74 #define DEBUG_WITH_TYPE(TYPE, X) do { } while (0)
     75 #endif
     76 
     77 /// EnableDebugBuffering - This defaults to false.  If true, the debug
     78 /// stream will install signal handlers to dump any buffered debug
     79 /// output.  It allows clients to selectively allow the debug stream
     80 /// to install signal handlers if they are certain there will be no
     81 /// conflict.
     82 ///
     83 extern bool EnableDebugBuffering;
     84 
     85 /// dbgs() - This returns a reference to a raw_ostream for debugging
     86 /// messages.  If debugging is disabled it returns errs().  Use it
     87 /// like: dbgs() << "foo" << "bar";
     88 raw_ostream &dbgs();
     89 
     90 // DEBUG macro - This macro should be used by passes to emit debug information.
     91 // In the '-debug' option is specified on the commandline, and if this is a
     92 // debug build, then the code specified as the option to the macro will be
     93 // executed.  Otherwise it will not be.  Example:
     94 //
     95 // DEBUG(dbgs() << "Bitset contains: " << Bitset << "\n");
     96 //
     97 #define DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X)
     98 
     99 } // End llvm namespace
    100 
    101 #endif
    102