Unifies the name-lookup mechanisms used in various parts of the AST

and separates lexical name lookup from qualified name lookup. In
particular:
  * Make DeclContext the central data structure for storing and
    looking up declarations within existing declarations, e.g., members
    of structs/unions/classes, enumerators in C++0x enums, members of
    C++ namespaces, and (later) members of Objective-C
    interfaces/implementations. DeclContext uses a lazily-constructed
    data structure optimized for fast lookup (array for small contexts,
    hash table for larger contexts). 

  * Implement C++ qualified name lookup in terms of lookup into
    DeclContext.

  * Implement C++ unqualified name lookup in terms of
    qualified+unqualified name lookup (since unqualified lookup is not
    purely lexical in C++!)

  * Limit the use of the chains of declarations stored in
    IdentifierInfo to those names declared lexically.

  * Eliminate CXXFieldDecl, collapsing its behavior into
    FieldDecl. (FieldDecl is now a ScopedDecl).

  * Make RecordDecl into a DeclContext and eliminates its
    Members/NumMembers fields (since one can just iterate through the
    DeclContext to get the fields).

llvm-svn: 60878

1 files changed, 10 insertions, 5 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 14db18c1345..b5f966d8621 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -353,7 +353,7 @@ static bool DeclCanBeLvalue(const NamedDecl *Decl, ASTContext &Ctx) {
         = dyn_cast<NonTypeTemplateParmDecl>(Decl))
     return NTTParm->getType()->isReferenceType();
 
-  return isa<VarDecl>(Decl) || isa<CXXFieldDecl>(Decl) ||
+  return isa<VarDecl>(Decl) || isa<FieldDecl>(Decl) ||
     // C++ 3.10p2: An lvalue refers to an object or function.
     (Ctx.getLangOptions().CPlusPlus &&
      (isa<FunctionDecl>(Decl) || isa<OverloadedFunctionDecl>(Decl)));
@@ -1222,10 +1222,15 @@ static int64_t evaluateOffsetOf(ASTContext& C, const Expr *E)
     const ASTRecordLayout &RL = C.getASTRecordLayout(RD);
     FieldDecl *FD = ME->getMemberDecl();
     
-    // FIXME: This is linear time.
-    unsigned i = 0, e = 0;
-    for (i = 0, e = RD->getNumMembers(); i != e; i++) {
-      if (RD->getMember(i) == FD)
+    // FIXME: This is linear time. And the fact that we're indexing
+    // into the layout by position in the record means that we're
+    // either stuck numbering the fields in the AST or we have to keep
+    // the linear search (yuck and yuck).
+    unsigned i = 0;
+    for (RecordDecl::field_iterator Field = RD->field_begin(),
+                                 FieldEnd = RD->field_end();
+         Field != FieldEnd; (void)++Field, ++i) {
+      if (*Field == FD)
         break;
     }