How to detect LLVM and its version through #define directives?

问题:

The question is quite clear I think. I'm trying to write a compiler detection header to be able to include in the application information on which compiler was used and which version.

This is part of the code I'm using:

/* GNU C Compiler Detection */ #elif defined __GNUC__     #ifdef __MINGW32__         #define COMPILER "MinGW GCC %d.%d.%d"     #else         #define COMPILER "GCC %d.%d.%d"     #endif     #define COMP_VERSION __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__ #endif 

Which could be used like this:

printf("  Compiled using " COMPILER "\n", COMP_VERSION); 

Is there any way to detect LLVM and its version? And CLANG?

回答1:

The __llvm__ and __clang__ macros are the official way to check for an LLVM compiler (llvm-gcc or clang) or clang, respectively.

__has_feature and __has_builtin are the recommended way of checking for optional compiler features when using clang, they are documented here.

Note that you can find a list of the builtin compiler macros for gcc, llvm-gcc, and clang using:

echo | clang -dM -E - 

This preprocesses an empty string and spits out all macros defined by the compiler.

回答2:

I cannot find an answer here, only links to answers, so for completeness, here is the answer:

__clang__             // set to 1 if compiler is clang __clang_major__       // integer: major marketing version number of clang __clang_minor__       // integer: minor marketing version number of clang __clang_patchlevel__  // integer: marketing patch level of clang __clang_version__     // string: full version number 

I get currently:

__clang__=1 __clang_major__=3 __clang_minor__=2 __clang_patchlevel__=0 __clang_version__="3.2 (tags/RELEASE_32/final)" 

回答3:

For clang, you shouldn't test its version number, you should check for features you want with feature checking macros.

回答4:

Snippet from InitPreprocessor.cpp:

  // Compiler version introspection macros.   DefineBuiltinMacro(Buf, "__llvm__=1");   // LLVM Backend   DefineBuiltinMacro(Buf, "__clang__=1");  // Clang Frontend    // Currently claim to be compatible with GCC 4.2.1-5621.   DefineBuiltinMacro(Buf, "__GNUC_MINOR__=2");   DefineBuiltinMacro(Buf, "__GNUC_PATCHLEVEL__=1");   DefineBuiltinMacro(Buf, "__GNUC__=4");   DefineBuiltinMacro(Buf, "__GXX_ABI_VERSION=1002");   DefineBuiltinMacro(Buf, "__VERSION__=\"4.2.1 Compatible Clang Compiler\""); 

I didn't find any way to get the version of llvm and clang itself, though..

回答5:

Take a look at the Pre-defined Compiler Macros page, select Compilers->Clang. There is information on many other macros for standards, compilers, libraries, OS, architectures and more.

回答6:

I agree that the best choice is to use has feature macroses, not version macroses. Example with boost:

#include   #if defined(BOOST_NO_CXX11_NOEXCEPT)  #if defined(BOOST_MSVC)   #define MY_NOEXCEPT throw()  #else   #define MY_NOEXCEPT  #endif #else  #define MY_NOEXCEPT noexcept #endif  void my_noexcept_function() MY_NOEXCEPT; // it's example, use BOOST_NOEXCEPT (: 

But anyway, if you need compiler version, you can use boost.predef:

#include  #include   int main() { #if (BOOST_COMP_CLANG)   std::cout 

Output examples:

Clang-30400000 Clang-50000000 

回答7:

Note that if you're using llvm to hack on bytecode, and thus #includeing llvm include files, you can check the macros in llvm/Config/llvm-config.h. And concretely:

/* Major version of the LLVM API */ #define LLVM_VERSION_MAJOR 3  /* Minor version of the LLVM API */ #define LLVM_VERSION_MINOR 8  /* Patch version of the LLVM API */ #define LLVM_VERSION_PATCH 0  /* LLVM version string */ #define LLVM_VERSION_STRING "3.8.0" 

文章来源: How to detect LLVM and its version through #define directives?