[AST] For USR generation, ignore symbols coming from the builtin module.

Swift SVN r17858

include/swift/AST/Module.h

@@ -394,6 +394,9 @@ public:
   /// \returns true if this module is the "swift" standard library module.
   bool isStdlibModule() const;
 
+  /// \returns true if this module is the "builtin" module.
+  bool isBuiltinModule() const;
+
   /// \returns true if this module is a system module; note that the StdLib is
   /// considered a system module.
   bool isSystemModule() const;

lib/AST/Module.cpp

@@ -1070,6 +1070,10 @@ bool Module::isStdlibModule() const {
   return !getParent() && Name == Ctx.StdlibModuleName;
 }
 
+bool Module::isBuiltinModule() const {
+  return this == Ctx.TheBuiltinModule;
+}
+
 bool Module::isSystemModule() const {
   if (isStdlibModule())
     return true;

lib/AST/USRGeneration.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/Module.h"
 #include "swift/AST/USRGeneration.h"
 #include "swift/AST/Mangle.h"
 #include "llvm/ADT/SmallString.h"
@@ -33,6 +34,8 @@ bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
 
   if (isa<VarDecl>(D) && !D->hasName())
     return true; // Ignore.
+  if (D->getModuleContext()->isBuiltinModule())
+    return true; // Ignore.
 
   ValueDecl *VD = const_cast<ValueDecl *>(D);