[clang] [clang] [Driver] Fix respecting libdir when locating flang runtime (PR #127345)

[Michał Górny via cfe-commits]

https://github.com/mgorny created https://github.com/llvm/llvm-project/pull/127345

Fix `tools::addFortranRuntimeLibraryPath` to use
`CLANG_INSTALL_LIBDIR_BASENAME` rather than hardwired `lib` directory. This fixes flang being unable to find its runtime when installed into nonstandard directory on a system using `lib64` for 64-bit libraries. While technically flang runtime could be installed with a different libdir value than clang, it seems rather unlikely.

>From a41cebcc8f7887864de2a0447d64faa9c95e02b8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny at gentoo.org>
Date: Sat, 15 Feb 2025 21:00:16 +0100
Subject: [PATCH] [clang] [Driver] Fix respecting libdir when locating flang
 runtime

Fix `tools::addFortranRuntimeLibraryPath` to use
`CLANG_INSTALL_LIBDIR_BASENAME` rather than hardwired `lib` directory.
This fixes flang being unable to find its runtime when installed into
nonstandard directory on a system using `lib64` for 64-bit libraries.
While technically flang runtime could be installed with a different
libdir value than clang, it seems rather unlikely.
---
 clang/lib/Driver/ToolChains/CommonArgs.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 2d01943ca1ac4..47e6fd9dbf902 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1367,7 +1367,7 @@ void tools::addFortranRuntimeLibraryPath(const ToolChain &TC,
   // lib64 instead of lib.
   SmallString<256> DefaultLibPath =
       llvm::sys::path::parent_path(TC.getDriver().Dir);
-  llvm::sys::path::append(DefaultLibPath, "lib");
+  llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
   if (TC.getTriple().isKnownWindowsMSVCEnvironment())
     CmdArgs.push_back(Args.MakeArgString("-libpath:" + DefaultLibPath));
   else