C++1y sized deallocation: if we have a use, but not a definition, of a sized

deallocation function (and the corresponding unsized deallocation function has
been declared), emit a weak discardable definition of the function that
forwards to the corresponding unsized deallocation.

This allows a C++ standard library implementation to provide both a sized and
an unsized deallocation function, where the unsized one does not just call the
sized one, for instance by putting both in the same object file within an
archive.

llvm-svn: 194055

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 3da8ba7309a..a523acfc431 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1093,6 +1093,9 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   Opts.Trigraphs = !Opts.GNUMode;
 
   Opts.DollarIdents = !Opts.AsmPreprocessor;
+
+  // C++1y onwards has sized global deallocation functions.
+  Opts.SizedDeallocation = Opts.CPlusPlus1y;
 }
 
 /// Attempt to parse a visibility value out of the given argument.
@@ -1310,7 +1313,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
   Opts.NoMathBuiltin = Args.hasArg(OPT_fno_math_builtin);
   Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
-  Opts.SizedDeallocation = Args.hasArg(OPT_fsized_deallocation);
+  Opts.SizedDeallocation |= Args.hasArg(OPT_fsized_deallocation);
   Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
   Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
   Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);