Initial implementation of argument dependent lookup (a.k.a. ADL,
a.k.a. Koenig lookup) in C++. Most of the pieces are in place, but for
two:
- In an unqualified call g(x), even if the name does not refer to
anything in the current scope, we can still find functions named
"g" based on ADL. We don't yet have this ability.
- ADL will need updating for friend functions and templates.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63692 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 36107e8..24f7965 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -1839,7 +1839,6 @@
Expr **Args = reinterpret_cast<Expr**>(args.release());
assert(Fn && "no function call expression");
FunctionDecl *FDecl = NULL;
- OverloadedFunctionDecl *Ovl = NULL;
// Determine whether this is a dependent call inside a C++ template,
// in which case we won't do any semantic analysis now.
@@ -1851,6 +1850,7 @@
else {
// Resolve the CXXDependentNameExpr to an actual identifier;
// it wasn't really a dependent name after all.
+ // FIXME: in the presence of ADL, this resolves too early.
OwningExprResult Resolved
= ActOnDeclarationNameExpr(S, FnName->getLocation(),
FnName->getName(),
@@ -1880,8 +1880,8 @@
return Owned(BuildCallToObjectOfClassType(S, Fn, LParenLoc, Args, NumArgs,
CommaLocs, RParenLoc));
- // Determine whether this is a call to a member function.
if (getLangOptions().CPlusPlus) {
+ // Determine whether this is a call to a member function.
if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(Fn->IgnoreParens()))
if (isa<OverloadedFunctionDecl>(MemExpr->getMemberDecl()) ||
isa<CXXMethodDecl>(MemExpr->getMemberDecl()))
@@ -1889,36 +1889,66 @@
CommaLocs, RParenLoc));
}
- // If we're directly calling a function or a set of overloaded
- // functions, get the appropriate declaration.
+ // If we're directly calling a function, get the appropriate declaration.
DeclRefExpr *DRExpr = NULL;
- if (ImplicitCastExpr *IcExpr = dyn_cast<ImplicitCastExpr>(Fn))
- DRExpr = dyn_cast<DeclRefExpr>(IcExpr->getSubExpr());
- else
- DRExpr = dyn_cast<DeclRefExpr>(Fn);
-
- if (DRExpr) {
- FDecl = dyn_cast<FunctionDecl>(DRExpr->getDecl());
- Ovl = dyn_cast<OverloadedFunctionDecl>(DRExpr->getDecl());
+ Expr *FnExpr = Fn;
+ bool ADL = true;
+ while (true) {
+ if (ImplicitCastExpr *IcExpr = dyn_cast<ImplicitCastExpr>(FnExpr))
+ FnExpr = IcExpr->getSubExpr();
+ else if (ParenExpr *PExpr = dyn_cast<ParenExpr>(FnExpr)) {
+ // FIXME: Where does the C++ standard say this?
+ ADL = false;
+ FnExpr = PExpr->getSubExpr();
+ } else if (isa<UnaryOperator>(FnExpr) &&
+ cast<UnaryOperator>(FnExpr)->getOpcode()
+ == UnaryOperator::AddrOf) {
+ FnExpr = cast<UnaryOperator>(FnExpr)->getSubExpr();
+ } else {
+ DRExpr = dyn_cast<DeclRefExpr>(FnExpr);
+ break;
+ }
}
+
+ if (DRExpr)
+ FDecl = dyn_cast<FunctionDecl>(DRExpr->getDecl());
- if (Ovl) {
- FDecl = ResolveOverloadedCallFn(Fn, Ovl, LParenLoc, Args, NumArgs,
- CommaLocs, RParenLoc);
- if (!FDecl)
- return ExprError();
+ if (getLangOptions().CPlusPlus && DRExpr &&
+ (FDecl || isa<OverloadedFunctionDecl>(DRExpr->getDecl()))) {
+ // C++ [basic.lookup.argdep]p1:
+ // When an unqualified name is used as the postfix-expression in
+ // a function call (5.2.2), other namespaces not considered
+ // during the usual unqualified lookup (3.4.1) may be searched,
+ // and namespace-scope friend func- tion declarations (11.4) not
+ // otherwise visible may be found.
+ if (DRExpr && isa<QualifiedDeclRefExpr>(DRExpr))
+ ADL = false;
- // Update Fn to refer to the actual function selected.
- Expr *NewFn = 0;
- if (QualifiedDeclRefExpr *QDRExpr = dyn_cast<QualifiedDeclRefExpr>(DRExpr))
- NewFn = new (Context) QualifiedDeclRefExpr(FDecl, FDecl->getType(),
- QDRExpr->getLocation(), false, false,
- QDRExpr->getSourceRange().getBegin());
- else
- NewFn = new (Context) DeclRefExpr(FDecl, FDecl->getType(),
- Fn->getSourceRange().getBegin());
- Fn->Destroy(Context);
- Fn = NewFn;
+ // We don't perform ADL for builtins.
+ if (FDecl && FDecl->getIdentifier() &&
+ FDecl->getIdentifier()->getBuiltinID())
+ ADL = false;
+
+ if ((DRExpr && isa<OverloadedFunctionDecl>(DRExpr->getDecl())) || ADL) {
+ FDecl = ResolveOverloadedCallFn(Fn, DRExpr->getDecl(), LParenLoc, Args,
+ NumArgs, CommaLocs, RParenLoc, ADL);
+ if (!FDecl)
+ return ExprError();
+
+ // Update Fn to refer to the actual function selected.
+ Expr *NewFn = 0;
+ if (QualifiedDeclRefExpr *QDRExpr
+ = dyn_cast<QualifiedDeclRefExpr>(DRExpr))
+ NewFn = new (Context) QualifiedDeclRefExpr(FDecl, FDecl->getType(),
+ QDRExpr->getLocation(),
+ false, false,
+ QDRExpr->getSourceRange().getBegin());
+ else
+ NewFn = new (Context) DeclRefExpr(FDecl, FDecl->getType(),
+ Fn->getSourceRange().getBegin());
+ Fn->Destroy(Context);
+ Fn = NewFn;
+ }
}
// Promote the function operand.