Introduce option -Wargument-larger-than[=N] which warns about function definitions if they take by-value
or return by-value any POD that is larger than some threshold (default is 64 bytes).

Implements rdar://8548050.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119583 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index dee123d..78f79c1 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -500,6 +500,11 @@
   HelpText<"Give inline C++ member functions default visibility by default">;
 def ftemplate_depth : Separate<"-ftemplate-depth">,
   HelpText<"Maximum depth of recursive template instantiation">;
+def Wargument_larger_than : Separate<"-Wargument-larger-than">,
+  HelpText<"Warn if a function definition returns or accepts an object larger "
+           "in bytes that a given value">;
+def Wargument_larger_than_EQ : Joined<"-Wargument-larger-than=">,
+  Alias<Wargument_larger_than>;
 def trigraphs : Flag<"-trigraphs">,
   HelpText<"Process trigraph sequences">;
 def fwritable_strings : Flag<"-fwritable-strings">,