Compiler Option: -gen

FreeBASIC

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Sets the backend code emitter.

Syntax

-gen < backend >

Parameters

backend

gas for x86 GAS assembly, gcc for GNU C, llvm for LLVM IR.

Description

The -gen compiler option sets the backend code emitter and assembler.

-gen gas

The compiler will emit GAS assembler code to a .asm file which will then be compiled to an object file using 'as'. This is fbc's original x86 code generation backend.

-gen gcc

The compiler will emit C code to a .c file which will then be compiled to an .asm file using 'gcc' as a high level assembler. The C backend is intended to make FB portable to more platforms than just x86. This requires gcc to be installed so that fbc can invoke it to compile the C code, also see Installing gcc for -gen gcc.

-gen llvm

The compiler will emit LLVM IR code to a .ll file which will then be compiled to an .asm file using 'llc'. The LLVM backend is still a work in progress. It is intended for the same purpose as the C backend, and could theoretically solve some of the C backend's problems, such as debugging meta data support.