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 /// EnableDebugBuffering - This defaults to false. If true, the debug 82 /// stream will install signal handlers to dump any buffered debug 83 /// output. It allows clients to selectively allow the debug stream 84 /// to install signal handlers if they are certain there will be no 85 /// conflict. 86 /// 87 extern bool EnableDebugBuffering; 88 89 /// dbgs() - This returns a reference to a raw_ostream for debugging 90 /// messages. If debugging is disabled it returns errs(). Use it 91 /// like: dbgs() << "foo" << "bar"; 92 raw_ostream &dbgs(); 93 94 // DEBUG macro - This macro should be used by passes to emit debug information. 95 // In the '-debug' option is specified on the commandline, and if this is a 96 // debug build, then the code specified as the option to the macro will be 97 // executed. Otherwise it will not be. Example: 98 // 99 // LLVM_DEBUG(dbgs() << "Bitset contains: " << Bitset << "\n"); 100 // 101 #define LLVM_DEBUG(X) DEBUG_WITH_TYPE(DEBUG_TYPE, X) 102 103 } // end namespace llvm 104 105 #endif // LLVM_SUPPORT_DEBUG_H 106