[all-commits] [llvm/llvm-project] 23e429: [Driver] Add --gcc-install-dir=

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 23e4299261d90ae5040766eceeeb11e1e2d46d5b
      https://github.com/llvm/llvm-project/commit/23e4299261d90ae5040766eceeeb11e1e2d46d5b
  Author: Fangrui Song <i at maskray.me>
  Date:   2022-09-21 (Wed, 21 Sep 2022)

  Changed paths:
    M clang/include/clang/Basic/DiagnosticDriverKinds.td
    M clang/include/clang/Driver/Options.td
    M clang/lib/Driver/ToolChains/Gnu.cpp
    A clang/test/Driver/gcc-install-dir.cpp

  Log Message:
  -----------
  [Driver] Add --gcc-install-dir=

This option specifies a GCC installation directory such as
/usr/lib/gcc/x86_64-linux-gnu/12, /usr/lib/gcc/x86_64-gentoo-linux-musl/11.2.0 .

It is intended to replace --gcc-toolchain=, which specifies a directory where
`lib/gcc{,-cross}` can be found. When --gcc-toolchain= is specified, the
selected `lib/gcc/$triple/$version` installation uses complex logic and the
largest GCC version is picked. There is no way to specify another version in the
presence of multiple GCC versions.

D25661 added gcc-config detection for Gentoo: `ScanGentooConfigs`.
The implementation may be simplified by using --gcc-install-dir=.

Reviewed By: mgorny

Differential Revision: https://reviews.llvm.org/D133329