[llvm-branch-commits] [clang] release/18.x: Reland Print library module manifest path again (#84881) (PR #85637)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-driver

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport 0e1e1fc8f0e

Requested by: @<!-- -->ChuanqiXu9

---
Full diff: https://github.com/llvm/llvm-project/pull/85637.diff


4 Files Affected:

- (modified) clang/include/clang/Driver/Driver.h (+10) 
- (modified) clang/include/clang/Driver/Options.td (+3) 
- (modified) clang/lib/Driver/Driver.cpp (+44) 
- (added) clang/test/Driver/modules-print-library-module-manifest-path.cpp (+36) 


``````````diff
diff --git a/clang/include/clang/Driver/Driver.h b/clang/include/clang/Driver/Driver.h
index 3ee1bcf2a69c9b..595f104e406d37 100644
--- a/clang/include/clang/Driver/Driver.h
+++ b/clang/include/clang/Driver/Driver.h
@@ -602,6 +602,16 @@ class Driver {
   // FIXME: This should be in CompilationInfo.
   std::string GetProgramPath(StringRef Name, const ToolChain &TC) const;
 
+  /// Lookup the path to the Standard library module manifest.
+  ///
+  /// \param C - The compilation.
+  /// \param TC - The tool chain for additional information on
+  /// directories to search.
+  //
+  // FIXME: This should be in CompilationInfo.
+  std::string GetStdModuleManifestPath(const Compilation &C,
+                                       const ToolChain &TC) const;
+
   /// HandleAutocompletions - Handle --autocomplete by searching and printing
   /// possible flags, descriptions, and its arguments.
   void HandleAutocompletions(StringRef PassedFlags) const;
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 175bedbfb4d01c..9b1c7cf6b8f35c 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5320,6 +5320,9 @@ def print_resource_dir : Flag<["-", "--"], "print-resource-dir">,
 def print_search_dirs : Flag<["-", "--"], "print-search-dirs">,
   HelpText<"Print the paths used for finding libraries and programs">,
   Visibility<[ClangOption, CLOption]>;
+def print_std_module_manifest_path : Flag<["-", "--"], "print-library-module-manifest-path">,
+  HelpText<"Print the path for the C++ Standard library module manifest">,
+  Visibility<[ClangOption, CLOption]>;
 def print_targets : Flag<["-", "--"], "print-targets">,
   HelpText<"Print the registered targets">,
   Visibility<[ClangOption, CLOption]>;
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 93cddf742d521d..dee5446a50ea59 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2194,6 +2194,12 @@ bool Driver::HandleImmediateArgs(const Compilation &C) {
     return false;
   }
 
+  if (C.getArgs().hasArg(options::OPT_print_std_module_manifest_path)) {
+    llvm::outs() << GetStdModuleManifestPath(C, C.getDefaultToolChain())
+                 << '\n';
+    return false;
+  }
+
   if (C.getArgs().hasArg(options::OPT_print_runtime_dir)) {
     if (std::optional<std::string> RuntimePath = TC.getRuntimePath())
       llvm::outs() << *RuntimePath << '\n';
@@ -6166,6 +6172,44 @@ std::string Driver::GetProgramPath(StringRef Name, const ToolChain &TC) const {
   return std::string(Name);
 }
 
+std::string Driver::GetStdModuleManifestPath(const Compilation &C,
+                                             const ToolChain &TC) const {
+  std::string error = "<NOT PRESENT>";
+
+  switch (TC.GetCXXStdlibType(C.getArgs())) {
+  case ToolChain::CST_Libcxx: {
+    std::string lib = GetFilePath("libc++.so", TC);
+
+    // Note when there are multiple flavours of libc++ the module json needs to
+    // look at the command-line arguments for the proper json.
+    // These flavours do not exist at the moment, but there are plans to
+    // provide a variant that is built with sanitizer instrumentation enabled.
+
+    // For example
+    //  StringRef modules = [&] {
+    //    const SanitizerArgs &Sanitize = TC.getSanitizerArgs(C.getArgs());
+    //    if (Sanitize.needsAsanRt())
+    //      return "modules-asan.json";
+    //    return "modules.json";
+    //  }();
+
+    SmallString<128> path(lib.begin(), lib.end());
+    llvm::sys::path::remove_filename(path);
+    llvm::sys::path::append(path, "modules.json");
+    if (TC.getVFS().exists(path))
+      return static_cast<std::string>(path);
+
+    return error;
+  }
+
+  case ToolChain::CST_Libstdcxx:
+    // libstdc++ does not provide Standard library modules yet.
+    return error;
+  }
+
+  return error;
+}
+
 std::string Driver::GetTemporaryPath(StringRef Prefix, StringRef Suffix) const {
   SmallString<128> Path;
   std::error_code EC = llvm::sys::fs::createTemporaryFile(Prefix, Suffix, Path);
diff --git a/clang/test/Driver/modules-print-library-module-manifest-path.cpp b/clang/test/Driver/modules-print-library-module-manifest-path.cpp
new file mode 100644
index 00000000000000..24797002b80f53
--- /dev/null
+++ b/clang/test/Driver/modules-print-library-module-manifest-path.cpp
@@ -0,0 +1,36 @@
+// Test that -print-library-module-manifest-path finds the correct file.
+
+// RUN: rm -rf %t && split-file %s %t && cd %t
+// RUN: mkdir -p %t/Inputs/usr/lib/x86_64-linux-gnu
+// RUN: touch %t/Inputs/usr/lib/x86_64-linux-gnu/libc++.so
+
+// RUN: %clang -print-library-module-manifest-path \
+// RUN:     -stdlib=libc++ \
+// RUN:     -resource-dir=%t/Inputs/usr/lib/x86_64-linux-gnu \
+// RUN:     --target=x86_64-linux-gnu 2>&1 \
+// RUN:   | FileCheck libcxx-no-module-json.cpp
+
+// RUN: touch %t/Inputs/usr/lib/x86_64-linux-gnu/modules.json
+// RUN: %clang -print-library-module-manifest-path \
+// RUN:     -stdlib=libc++ \
+// RUN:     -resource-dir=%t/Inputs/usr/lib/x86_64-linux-gnu \
+// RUN:     --target=x86_64-linux-gnu 2>&1 \
+// RUN:   | FileCheck libcxx.cpp
+
+// RUN: %clang -print-library-module-manifest-path \
+// RUN:     -stdlib=libstdc++ \
+// RUN:     -resource-dir=%t/Inputs/usr/lib/x86_64-linux-gnu \
+// RUN:     --target=x86_64-linux-gnu 2>&1 \
+// RUN:   | FileCheck libstdcxx.cpp
+
+//--- libcxx-no-module-json.cpp
+
+// CHECK: <NOT PRESENT>
+
+//--- libcxx.cpp
+
+// CHECK: {{.*}}/Inputs/usr/lib/x86_64-linux-gnu{{/|\\}}modules.json
+
+//--- libstdcxx.cpp
+
+// CHECK: <NOT PRESENT>

``````````

</details>


https://github.com/llvm/llvm-project/pull/85637