Fix linkage of 'static inline' Clang-imported definitions

If an external SIL function has a Clang-generated body, I think this
means we have a static function, and we want to use Shared linkage,
not Public.

Add a new flag to SILFunction for this and plumb it through to
appease assertions from SILVerifier.

Swift SVN r31763

include/swift/SIL/SILDeclRef.h

@@ -348,10 +348,14 @@ struct SILDeclRef {
   /// True if the referenced entity is some kind of thunk.
   bool isThunk() const;
 
-  /// True if the referenced entity is generated on behalf of the Clang
+  /// True if the referenced entity is emitted by Swift on behalf of the Clang
   /// importer.
   bool isClangImported() const;
 
+  /// True if the referenced entity is emitted by Clang on behalf of the Clang
+  /// importer.
+  bool isClangGenerated() const;
+
   bool isImplicit() const {
     if (hasDecl())
       return getDecl()->isImplicit();

include/swift/SIL/SILFunction.h

@@ -120,11 +120,13 @@ private:
   /// The linkage of the function.
   unsigned Linkage : NumSILLinkageBits;
 
-  /// This flags indicates if a function can be
-  /// eliminated by dead function elimination.
-  /// If it is unset, DFE will preserve the function
-  /// and make it public.
-  unsigned KeepAsPublic: 1;
+  /// This flag indicates if a function can be eliminated by dead function
+  /// elimination. If it is unset, DFE will preserve the function and make
+  /// it public.
+  unsigned KeepAsPublic : 1;
+
+  /// This flag indicates if a function has a body generated by Clang.
+  unsigned ForeignBody : 1;
 
   /// This is the number of uses of this SILFunction inside the SIL.
   /// It does not include references from debug scopes.
@@ -421,6 +423,10 @@ public:
   bool isKeepAsPublic() const { return KeepAsPublic; }
   void setKeepAsPublic(bool keep) { KeepAsPublic = keep; }
 
+  /// Get this function's foreign body attribute.
+  HasForeignBody_t hasForeignBody() const { return HasForeignBody_t(ForeignBody); }
+  void setForeignBody(HasForeignBody_t foreign) { ForeignBody = foreign; }
+
   /// Retrieve the generic parameter list containing the contextual archetypes
   /// of the function.
   ///

include/swift/SIL/SILLinkage.h

@@ -84,12 +84,18 @@ enum {
   NumSILLinkageBits = 3
 };
 
-/// Reslated to linkage: flag if a function or global variable is fragle.
+/// Related to linkage: flag if a function or global variable is fragile.
 enum IsFragile_t {
   IsNotFragile,
   IsFragile
 };
-  
+
+/// True if we have an inline body generated by Clang.
+enum HasForeignBody_t {
+  DoesNotHaveForeignBody,
+  HasForeignBody
+};
+
 /// Strip external from public_external, hidden_external. Otherwise just return
 /// the linkage.
 inline SILLinkage stripExternalFromLinkage(SILLinkage linkage) {