[all-commits] [llvm/llvm-project] e9d454: [Driver] Report warnings for unclaimed TargetSpeci...

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e9d454d1c195958645fb0948f8b97262e7f8b33a
      https://github.com/llvm/llvm-project/commit/e9d454d1c195958645fb0948f8b97262e7f8b33a
  Author: Fangrui Song <i at maskray.me>
  Date:   2023-08-31 (Thu, 31 Aug 2023)

  Changed paths:
    M clang/lib/Driver/Driver.cpp
    M clang/lib/Driver/ToolChains/AIX.cpp
    M clang/lib/Driver/ToolChains/Arch/X86.cpp
    M clang/lib/Driver/ToolChains/Arch/X86.h
    M clang/lib/Driver/ToolChains/CommonArgs.cpp
    M clang/test/Driver/aarch64-target-as-march.s
    A clang/test/Driver/target-specific.s
    M clang/test/Driver/x86-mfpmath.c

  Log Message:
  -----------
  [Driver] Report warnings for unclaimed TargetSpecific options for assembler input

This patch amends D151590 to not error for unlaimed TargetSpecific
options for `-x assembler` input files. This input type causes Driver to
construct tools::ClangAs (-fintegrated-as) or other assemblers (e.g.
tools::gnutools::Assembler) Their ConstructJobs methods, unlike
Clang::ConstructJobs, claim very few options. If an option is unclaimed,
it either leads to a -Wunused-command-line-argument warning or an error
(if `TargetSpecific` is set):
```
% clang '-###' --target=aarch64 -mbranch-protection=bti -c a.s
clang: error: unsupported option '-mbranch-protection=' for target 'aarch64'
```

It seems that downgrading the diagnostic to warning is most useful as
many users use CFLAGS even for `.s` files:
```
clang --target=aarch64 -mbranch-protection=bti -S a.c
clang --target=aarch64 -mbranch-protection=bti -c a.s
```

I decide not to suppress the warning so that
-Wunused-command-line-argument lovers still get a warning, and help
projects use proper ASFLAGS/CFLAGS/etc.

Note: `-mbranch-protection=bti a.S` currently has no warning as `-x assembler-with-cpp`
instructs clangDriver to select tools::Clang and claim most options.

Revert D159010 to demonstrate that we emit a warning for -mfpmath= for
`-x assembler` input.

Modify my AIX cleanup cd18efb61d759405956dbd30e4b5f2720d8e1783 to
add an err_drv_unsupported_opt_for_target.

Reviewed By: thesamesam

Differential Revision: https://reviews.llvm.org/D159173