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. If 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, ...) \ 65 do { \ 66 if (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)) { \ 67 __VA_ARGS__; \ 68 } \ 69 } while (false) 70 71 #else 72 #define isCurrentDebugType(X) (false) 73 #define setCurrentDebugType(X) do { (void)(X); } while (false) 74 #define setCurrentDebugTypes(X, N) do { (void)(X); (void)(N); } while (false) 75 #define DEBUG_WITH_TYPE(TYPE, ...) \ 76 do { \ 77 } while (false) 78 #endif 79 80 /// This boolean is set to true if the '-debug' command line option 81 /// is specified. This should probably not be referenced directly, instead, use 82 /// the DEBUG macro below. 83 /// 84 extern bool DebugFlag; 85 86 /// EnableDebugBuffering - This defaults to false. If true, the debug 87 /// stream will install signal handlers to dump any buffered debug 88 /// output. It allows clients to selectively allow the debug stream 89 /// to install signal handlers if they are certain there will be no 90 /// conflict. 91 /// 92 extern bool EnableDebugBuffering; 93 94 /// dbgs() - This returns a reference to a raw_ostream for debugging 95 /// messages. If debugging is disabled it returns errs(). Use it 96 /// like: dbgs() << "foo" << "bar"; 97 raw_ostream &dbgs(); 98 99 // DEBUG macro - This macro should be used by passes to emit debug information. 100 // If the '-debug' option is specified on the commandline, and if this is a 101 // debug build, then the code specified as the option to the macro will be 102 // executed. Otherwise it will not be. Example: 103 // 104 // LLVM_DEBUG(dbgs() << "Bitset contains: " << Bitset << "\n"); 105 // 106 #define LLVM_DEBUG(...) DEBUG_WITH_TYPE(DEBUG_TYPE, __VA_ARGS__) 107 108 } // end namespace llvm 109 110 #endif // LLVM_SUPPORT_DEBUG_H 111