1 files changed, 44 insertions, 0 deletions
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index e3f5f59..5015ce9 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2197,6 +2197,12 @@ 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';
@@ -6186,6 +6192,44 @@ 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);