Add support to -Wa,--version in clang

Clang currently only supports -Wa,--version when -no-integrated-as is
used. This adds support to -Wa,--version with -integrated-as.

Link:
ClangBuiltLinux/linux#1320

Reviewed By: nickdesaulniers, MaskRay

Differential Revision: https://reviews.llvm.org/D99556

Author: jcai19

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2549,6 +2549,8 @@ static void CollectArgsForIntegratedAssembler(Compilation &C,
         // -fdebug-compilation-dir (without '=') here.
         CmdArgs.push_back("-fdebug-compilation-dir");
         CmdArgs.push_back(Value.data());
+      } else if (Value == "--version") {
+        D.PrintVersion(C, llvm::outs());
       } else {
         D.Diag(diag::err_drv_unsupported_option_argument)
             << A->getOption().getName() << Value;

clang/test/Driver/as-version.s

@@ -0,0 +1,9 @@
+// Test version information.
+
+// RUN: %clang -Wa,--version -c -fintegrated-as %s -o /dev/null \
+// RUN:   | FileCheck --check-prefix=IAS %s
+// IAS: clang version
+
+// RUN: %clang -Wa,--version -c -fno-integrated-as %s -o /dev/null \
+// RUN:   | FileCheck --check-prefix=GAS %s
+// GAS-NOT: clang