[clang] 7e42b97 - [Tooling] Resolve tool names from PATH in CommonOptionsParser (#213681)

[via cfe-commits]

Author: Zeyi Xu
Date: 2026-08-15T00:04:38+08:00
New Revision: 7e42b97db3c1b574dae3af4d82bb48676bd5005f

URL: https://github.com/llvm/llvm-project/commit/7e42b97db3c1b574dae3af4d82bb48676bd5005f
DIFF: https://github.com/llvm/llvm-project/commit/7e42b97db3c1b574dae3af4d82bb48676bd5005f.diff

LOG: [Tooling] Resolve tool names from PATH in CommonOptionsParser (#213681)

Resolve tool names through `PATH` before passing compilation commands to
the Clang driver.

Compilation databases may specify the tool by name rather than by
absolute path:

e.g.
```json
[
  {
    "directory": "/path/to/project",
    "command": "clang -c test.c",
    "file": "test.c"
  }
]
```

LibTooling invokes the driver in-process, so the compiler name in the
example is not resolved by a shell. As a result, the driver can't find
installation-relative resources.

This could be problematic with Homebrew Clang, where the missing
executable path prevents the driver from loading the SDK configuration
and causes system headers to be unavailable.

Closes #213633

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.md
    clang/lib/Tooling/CommonOptionsParser.cpp
    clang/test/Tooling/clang-check-mac-libcxx-relpath.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md
index 6548e8a6028cb..a7a31946610ae 100644
--- a/clang/docs/ReleaseNotes.md
+++ b/clang/docs/ReleaseNotes.md
@@ -179,6 +179,9 @@ features cannot lower the translation-unit ABI level;
 
 ### Non-comprehensive list of changes in this release
 
+- Clang tools now resolve tool names without a path in compilation databases
+  through `PATH`.
+
 - Clang now allows GNU computed `goto` extension in `constexpr` functions, matching the relaxed
   `constexpr` function body rules introduced in C++23.
 

diff  --git a/clang/lib/Tooling/CommonOptionsParser.cpp b/clang/lib/Tooling/CommonOptionsParser.cpp
index c8c3ca98323e2..454e7ca68a65f 100644
--- a/clang/lib/Tooling/CommonOptionsParser.cpp
+++ b/clang/lib/Tooling/CommonOptionsParser.cpp
@@ -139,6 +139,7 @@ llvm::Error CommonOptionsParser::init(
           new FixedCompilationDatabase(".", std::vector<std::string>()));
     }
   }
+  Compilations = inferToolLocation(std::move(Compilations));
   auto AdjustingCompilations =
       std::make_unique<ArgumentsAdjustingCompilations>(
           std::move(Compilations));

diff  --git a/clang/test/Tooling/clang-check-mac-libcxx-relpath.cpp b/clang/test/Tooling/clang-check-mac-libcxx-relpath.cpp
index 7a801a2814402..bcee5ad949fbe 100644
--- a/clang/test/Tooling/clang-check-mac-libcxx-relpath.cpp
+++ b/clang/test/Tooling/clang-check-mac-libcxx-relpath.cpp
@@ -12,6 +12,11 @@
 // RUN: cp "%s" "%t/test.cpp"
 // clang-check will produce an error code if the mock library is not found.
 // RUN: clang-check -p "%t" "%t/test.cpp"
+//
+// Resolve a driver without a path through PATH.
+// RUN: chmod +x %t/mock-libcxx/bin/clang
+// RUN: echo '[{"directory":"%t","command":"clang -stdlib=libc++ -target x86_64-apple-darwin -c test.cpp","file":"test.cpp"}]' | sed -e 's/\\/\//g' > %t/compile_commands.json
+// RUN: env "PATH=%t/mock-libcxx/bin%{pathsep}%PATH%" clang-check -p "%t" "%t/test.cpp"
 
 #include <mock_vector>
 vector v;