1 files changed, 12 insertions, 0 deletions
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index eb0df5221dc..6e2f1f302c2 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3545,6 +3545,18 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // Select the appropriate action.
   RewriteKind rewriteKind = RK_None;
 
+  // If CollectArgsForIntegratedAssembler() isn't called below, call it here
+  // with a dummy args list to mark assembler flags as used even when not
+  // running an assembler. Otherwise, clang would emit "argument unused"
+  // warnings for assembler flags when e.g. adding "-E" to flags while debugging
+  // something. That'd be somewhat inconvenient, and it's also inconsistent with
+  // most other flags -- we don't warn on -ffunction-sections not being used
+  // in -E mode either for example, even though it's not really used either.
+  if (!isa<AssembleJobAction>(JA)) {
+    ArgStringList DummyArgs;
+    CollectArgsForIntegratedAssembler(C, Args, DummyArgs, D);
+  }
+
   if (isa<AnalyzeJobAction>(JA)) {
     assert(JA.getType() == types::TY_Plist && "Invalid output type.");
     CmdArgs.push_back("-analyze");