[cfe-commits] r153722 - in /cfe/trunk: NOTES.txt lib/CodeGen/CGClass.cpp

[John McCall]

Author: rjmccall
Date: Thu Mar 29 23:25:03 2012
New Revision: 153722

URL: http://llvm.org/viewvc/llvm-project?rev=153722&view=rev
Log:
Add a note about a missing optimization in the case of virtual
inheritance.

Modified:
    cfe/trunk/NOTES.txt
    cfe/trunk/lib/CodeGen/CGClass.cpp

Modified: cfe/trunk/NOTES.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/NOTES.txt?rev=153722&r1=153721&r2=153722&view=diff
==============================================================================
--- cfe/trunk/NOTES.txt (original)
+++ cfe/trunk/NOTES.txt Thu Mar 29 23:25:03 2012
@@ -101,3 +101,14 @@
 metaprogramming.
 
 //===---------------------------------------------------------------------===//
+
+We can still apply a modified version of the constructor/destructor
+delegation optimization in cases of virtual inheritance where:
+  - there is no function-try-block,
+  - the constructor signature is not variadic, and
+  - the parameter variables can safely be copied and repassed
+    to the base constructor because either
+    - they have not had their addresses taken by the vbase initializers or
+    - they were passed indirectly.
+
+//===---------------------------------------------------------------------===//

Modified: cfe/trunk/lib/CodeGen/CGClass.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGClass.cpp?rev=153722&r1=153721&r2=153722&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGClass.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGClass.cpp Thu Mar 29 23:25:03 2012
@@ -731,6 +731,9 @@
 
   EHScopeStack::stable_iterator CleanupDepth = EHStack.stable_begin();
 
+  // TODO: in restricted cases, we can emit the vbase initializers of
+  // a complete ctor and then delegate to the base ctor.
+
   // Emit the constructor prologue, i.e. the base and member
   // initializers.
   EmitCtorPrologue(Ctor, CtorType, Args);