Lazily declare default constructors. We now delay the construction of

declarations for implicit default constructors, copy constructors,
copy assignment operators, and destructors. On a "simple" translation
unit that includes a bunch of C++ standard library headers, we
generate relatively few of these implicit declarations now:

  4/159 implicit default constructors created
  18/236 implicit copy constructors created
  70/241 implicit copy assignment operators created
  0/173 implicit destructors created

And, on this translation unit, this optimization doesn't really
provide any benefit. I'll do some more performance measurements soon,
but this completes the implementation work for <rdar://problem/8151045>.

llvm-svn: 107551

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 4b1909e57c6..7ce9c64de03 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -32,7 +32,7 @@ CXXRecordDecl::DefinitionData::DefinitionData(CXXRecordDecl *D)
     Abstract(false), HasTrivialConstructor(true),
     HasTrivialCopyConstructor(true), HasTrivialCopyAssignment(true),
     HasTrivialDestructor(true), ComputedVisibleConversions(false),
-    DeclaredCopyConstructor(false), 
+    DeclaredDefaultConstructor(false), DeclaredCopyConstructor(false), 
     DeclaredCopyAssignment(false), DeclaredDestructor(false),
     Bases(0), NumBases(0), VBases(0), NumVBases(0),
     Definition(D), FirstFriend(0) {
@@ -277,6 +277,9 @@ CXXRecordDecl::addedConstructor(ASTContext &Context,
   // Note that we have a user-declared constructor.
   data().UserDeclaredConstructor = true;
 
+  // Note that we have no need of an implicitly-declared default constructor.
+  data().DeclaredDefaultConstructor = true;
+  
   // C++ [dcl.init.aggr]p1:
   //   An aggregate is an array or a class (clause 9) with no
   //   user-declared constructors (12.1) [...].