Swift: add clang ignored flag

swift/tools/tracing-config.lua

@@ -25,11 +25,29 @@ function RegisterExtractorPack(id)
       end
     end
 
+    -- removes unsupported -Xcc flag, e.g, calling strip_unsupported_xcc_arg('-foo', 2) against
+    -- swift -Xcc -foo -Xcc -bar main.swift
+    -- will only leave 'swift main.swift' removing both -Xcc -foo, and also -Xcc -bar
+    -- removes unsupported CLI arg passed to clang via -Xcc together with the following how_many args
+    function strip_unsupported_clang_arg(args, arg, how_many)
+        local index = indexOf(args, arg)
+        if index and index > 0 and args[index - 1] == '-Xcc' then
+            index = index - 1  -- start from -Xcc
+            how_many = 2 * (how_many + 1)  -- need to remove initial -Xcc <arg> as well as following -Xcc prefixed flags
+            while (how_many > 0)
+            do
+                table.remove(args, index)
+                how_many = how_many - 1
+            end
+        end
+    end
+
     function strip_unsupported_args(args)
       strip_unsupported_arg(args, '-emit-localized-strings', 0)
       strip_unsupported_arg(args, '-emit-localized-strings-path', 1)
       strip_unsupported_arg(args, '-stack-check', 0)
       strip_unsupported_arg(args, '-experimental-skip-non-inlinable-function-bodies-without-types', 0)
+      strip_unsupported_clang_arg(args, '-ivfsstatcache', 1)
     end
 
     -- xcodebuild does not always specify the -resource-dir in which case the compiler falls back