What is fno RTTI?
-fno-rtti. Disable generation of information about every class with virtual functions for use by the C++ runtime type identification features (` dynamic_cast ‘ and ` typeid ‘). If you don’t use those parts of the language, you can save some space by using this flag.
What is the clang command?
Clang /ˈklæŋ/ is a compiler front end for the C, C++, Objective-C, and Objective-C++ programming languages, as well as the OpenMP, OpenCL, RenderScript, CUDA, and HIP frameworks.
Is RTTI slow?
Following the philosophy of KCL, our RTTI system will fulfill the following requirements: Must support at least: dynamic cast, multiple inheritance, and retrieving the type name as a string. As elegant syntax as possible. Efficient: one of the main complaints about STL RTTI and dynamic_cast is that is it slow.
How do I enable RTTI?
RTTI will be enabled or disabled when compiling your program via compiler options – it’s not something enabled or disabled in the Unix environment globally. The easiest way to see if it’s enabled by default for your compiler is to just try compiling some code using RTTI.
What does LLVM stand for?
low level virtual machine
LLVM is an acronym that stands for low level virtual machine. It also refers to a compiling technology called the LLVM project, which is a collection of modular and reusable compiler and toolchain technologies.
What is Clang and LLVM?
Clang is an “LLVM native” C/C++/Objective-C compiler, which aims to deliver amazingly fast compiles, extremely useful error and warning messages and to provide a platform for building great source level tools.
Does dynamic_cast use RTTI?
The dynamic_cast operator is intended to be the most heavily used RTTI component. “The need for dynamic_cast generally arises because you want to perform derived class operation on a derived class object, but you have only a pointer or reference-to-base” said Scott Meyers in his book “Effective C++”.
Does Typeid require RTTI?
Just like dynamic_cast, the typeid does not always need to use RTTI mechanism to work correctly. If the argument of the typeid expression is non-polymorphic type, then no runtime check is performed. Instead, the information about the type is known at the compile-time.
Is Rtti enabled by default?
RTTI support is on by default in GCC, the option -fno-rtti turns off support (in case you’re using GCC and maybe someone’s turned off RTTI in a makefile or something).
How do I use RTTI in C++?
RTTI (Run-time type Information) in C++ For example, dynamic_cast uses RTTI and following program fails with error “cannot dynamic_cast `b’ (of type `class B*’) to type `class D*’ (source type is not polymorphic) ” because there is no virtual function in the base class B.
Who owns LLVM?
LLVM
| The LLVM logo, a stylized wyvern | |
|---|---|
| Original author(s) | Vikram Adve, Chris Lattner |
| Developer(s) | LLVM Developer Group |
| Initial release | 2003 |
| Stable release | 13.0.0 / September 30, 2021 |
Where is LLVM used?
LLVM is a library that is used to construct, optimize and produce intermediate and/or binary machine code. LLVM can be used as a compiler framework, where you provide the “front end” (parser and lexer) and the “back end” (code that converts LLVM’s representation to actual machine code).