Sema: Preserve attributes on parameters in instantiated function templates.

This was causing correctness issues for ARC and the static analyzer when a
function template has "consumed" Objective-C object parameters (i.e.
parameters that will be released by the function before returning).

The fix is threefold:
(1) Actually copy over the attributes from old ParmVarDecls to new ones.
(2) Have Sema::BuildFunctionType only work for building FunctionProtoTypes,
    which it was doing anyway. This allows us to pass an ExtProtoInfo
    instead of a plain ExtInfo and several flags.
(3) Drop param attributes as part of StripImplicitInstantiation, which is
    used when an implicit instantiation is followed by an explicit one.

<rdar://problem/12685622>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176728 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 75f255e945..fd0641995b 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -5648,11 +5648,15 @@ Decl *Sema::ActOnStartOfFunctionTemplateDef(Scope *FnBodyScope,
 /// \brief Strips various properties off an implicit instantiation
 /// that has just been explicitly specialized.
 static void StripImplicitInstantiation(NamedDecl *D) {
-  // FIXME: "make check" is clean if the call to dropAttrs() is commented out.
   D->dropAttrs();
 
   if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
     FD->setInlineSpecified(false);
+
+    for (FunctionDecl::param_iterator I = FD->param_begin(),
+                                      E = FD->param_end();
+         I != E; ++I)
+      (*I)->dropAttrs();
   }
 }