Don't explicitly represent OverloadedFunctionDecls within

DeclContext. Instead, just keep the list of currently-active
declarations and only build the OverloadedFunctionDecl when we
absolutely need it.

This is a half-step toward eliminating the need to explicitly build
OverloadedFunctionDecls that store sets of overloaded
functions. This was suggested by Argiris a while back, and it's a good
thing for several reasons: first, it eliminates the messy logic that
currently tries to keep the OverloadedFunctionDecl in sync with the 
declarations that are being added. Second, it will (eventually)
eliminate the need to allocate memory for overload sets, which could
help performance. Finally, it helps set us up for when name lookup can
return multiple (possibly ambiguous) results, as can happen with
lookup of class members in C++.

Next steps: make the IdentifierResolver store overloads as separate
entries in its list rather than replacing them with an
OverloadedFunctionDecl now, then see how far we can go toward
eliminating OverloadedFunctionDecl entirely.

llvm-svn: 61357

1 files changed, 6 insertions, 34 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 8a37bbbe7b4..918fd2ac9a7 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -20,6 +20,7 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Parse/DeclSpec.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Compiler.h"
 #include <algorithm> // for std::equal
 #include <map>
@@ -844,23 +845,7 @@ void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
     CopyConstructor->setParams(&FromParam, 1);
 
     ClassDecl->addedConstructor(Context, CopyConstructor);
-    DeclContext::lookup_result Lookup = ClassDecl->lookup(Context, Name);
-    if (Lookup.first == Lookup.second 
-        || (!isa<CXXConstructorDecl>(*Lookup.first) &&
-            !isa<OverloadedFunctionDecl>(*Lookup.first)))
-      ClassDecl->addDecl(Context, CopyConstructor);
-    else {
-      OverloadedFunctionDecl *Ovl 
-        = dyn_cast<OverloadedFunctionDecl>(*Lookup.first);
-      if (!Ovl) {
-        Ovl = OverloadedFunctionDecl::Create(Context, ClassDecl, Name);
-        Ovl->addOverload(cast<CXXConstructorDecl>(*Lookup.first));
-        ClassDecl->insert(Context, Ovl);
-      }
-
-      Ovl->addOverload(CopyConstructor);
-      ClassDecl->addDecl(Context, CopyConstructor, false);
-    }
+    ClassDecl->addDecl(Context, CopyConstructor);
   }
 
   if (!ClassDecl->hasUserDeclaredDestructor()) {
@@ -1470,23 +1455,10 @@ Sema::PerformInitializationByConstructor(QualType ClassType,
   DeclarationName ConstructorName 
     = Context.DeclarationNames.getCXXConstructorName(
                        Context.getCanonicalType(ClassType.getUnqualifiedType()));
-  DeclContext::lookup_const_result Lookup 
-    = ClassDecl->lookup(Context, ConstructorName);
-  if (Lookup.first == Lookup.second)
-    /* No constructors */;
-  else if (OverloadedFunctionDecl *Constructors 
-             = dyn_cast<OverloadedFunctionDecl>(*Lookup.first)) {
-    for (OverloadedFunctionDecl::function_iterator Con 
-           = Constructors->function_begin();
-         Con != Constructors->function_end(); ++Con) {
-      CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con);
-      if ((Kind == IK_Direct) ||
-          (Kind == IK_Copy && Constructor->isConvertingConstructor()) ||
-          (Kind == IK_Default && Constructor->isDefaultConstructor()))
-        AddOverloadCandidate(Constructor, Args, NumArgs, CandidateSet);
-    }
-  } else if (CXXConstructorDecl *Constructor 
-               = dyn_cast<CXXConstructorDecl>(*Lookup.first)) {
+  DeclContext::lookup_const_iterator Con, ConEnd;
+  for (llvm::tie(Con, ConEnd) = ClassDecl->lookup(Context, ConstructorName);
+       Con != ConEnd; ++Con) {
+    CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con);
     if ((Kind == IK_Direct) ||
         (Kind == IK_Copy && Constructor->isConvertingConstructor()) ||
         (Kind == IK_Default && Constructor->isDefaultConstructor()))