Add command line options and build system support for specifying LLVM target cpu and features #2595
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src/link.cpp
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| @@ -22,7 +22,7 @@ struct LinkJob { | |||
| static CodeGen *create_child_codegen(CodeGen *parent_gen, Buf *root_src_path, OutType out_type, | |||
| ZigLibCInstallation *libc) | |||
| { | |||
| CodeGen *child_gen = codegen_create(nullptr, root_src_path, parent_gen->zig_target, out_type, | |||
| CodeGen *child_gen = codegen_create(nullptr, root_src_path, parent_gen->zig_target, out_type, | |||
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There's a stray space at the end of this line.
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I know some people care a lot about formatting, but here the policy is to not give contributors a hard time about it. Don't worry about stray spaces or formatting. Let's focus on the logic and the bigger picture.
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Ah, my apologies. I didn't mean to be harsh.
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Thanks for this patch.
Although LLVM is currently the only backend of Zig, the language does not depend on LLVM, and it is planned to support non-LLVM backends. Even though the target cpu and features options need to eventually be given to LLVM in a way that LLVM understands, we still need to expose these options in a way that is independent of LLVM. That means the CLI option cannot be called --llvm-cpu or --llvm- anything. zig targets must list all the possible options. The CLI should be able to reject invalid options without consulting LLVM.
As mentioned in #2051 (in this comment specifically), the Zig compiler currently does not allow the override of the LLVM cpu (-mcpu) and features (-mattr) options. This PR adds the command-line flags
--llvm-cpuand--llvm-featuresto the build-* compiler commands. In addition, the build system has been updated to support these options as well. The strings accepted by the--llvm-cpuand--llvm-featuresoptions are equivalent to those accepted by clang and llc with-mcpuand-mattr, respectively.This PR does not include a way of listing supported cpus or features of a given architecture. The easiest way to obtain such a list is to run
llc -march=<arch> -mcpu=help, replacing<arch>with the desired architecture, i.e.armoravr.