[clang] Bing --gcc-triple to flang (PR #165886)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Konrad Kleine (kwk)

<details>
<summary>Changes</summary>

When there are multiple `gcc` versions installed, we want `flang` to be able to find the right one based on the triple. Here's `flang` selecting an unwanted `gcc` candidate installation, namely
`/usr/lib/gcc/x86_64-linux-gnu/15`:

```
~/src/llvm-project/main/build-RelWithDebInfo > ./bin/flang -v
flang version 22.0.0custombuild
Target: x86_64-redhat-linux-gnu
Thread model: posix
InstalledDir: /home/fedora/src/llvm-project/main/build-RelWithDebInfo/bin
System configuration file directory: /etc/clang/
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/15
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/15
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/15
Candidate multilib: .;@<!-- -->m64
Candidate multilib: 32;@<!-- -->m32
Selected multilib: .;@<!-- -->m64
```

When passing `--gcc-triple=x86_64-redhat-linux` we get the desired gcc candidate installation, namely `/usr/lib/gcc/x86_64-redhat-linux/15`:

```
~/src/llvm-project/main/build-RelWithDebInfo > ./bin/flang --gcc-triple=x86_64-redhat-linux -v
flang version 22.0.0custombuild
Target: x86_64-redhat-linux-gnu
Thread model: posix
InstalledDir: /home/fedora/src/llvm-project/main/build-RelWithDebInfo/bin
System configuration file directory: /etc/clang/
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/15
Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/15
Candidate multilib: .;@<!-- -->m64
Candidate multilib: 32;@<!-- -->m32
Selected multilib: .;@<!-- -->m64
```

---
Full diff: https://github.com/llvm/llvm-project/pull/165886.diff


1 Files Affected:

- (modified) clang/include/clang/Driver/Options.td (+1) 


``````````diff
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index cb5cb888c6da7..8b728e9acbb8b 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -741,6 +741,7 @@ def gcc_toolchain : Joined<["--"], "gcc-toolchain=">, Flags<[NoXarchOption]>,
     "Specify a directory where Flang can find 'lib{,32,64}/gcc{,-cross}/$triple/$version'. "
     "Flang will use the GCC installation with the largest version">;
 def gcc_triple_EQ : Joined<["--"], "gcc-triple=">,
+  Visibility<[ClangOption, FlangOption]>,
   HelpText<"Search for the GCC installation with the specified triple.">;
 def CC : Flag<["-"], "CC">, Visibility<[ClangOption, CC1Option]>,
   Group<Preprocessor_Group>,

``````````

</details>


https://github.com/llvm/llvm-project/pull/165886