Add support for calls to dependent names within templates, e.g.,
template<typename T> void f(T x) {
g(x); // g is a dependent name, so don't even bother to look it up
g(); // error: g is not a dependent name
}
Note that when we see "g(", we build a CXXDependentNameExpr. However,
if none of the call arguments are type-dependent, we will force the
resolution of the name "g" and replace the CXXDependentNameExpr with
its result.
GCC actually produces a nice error message when you make this
mistake, and even offers to compile your code with -fpermissive. I'll
do the former next, but I don't plan to do the latter.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60618 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 85cd2c8..b396e1c 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -461,7 +461,7 @@
SourceLocation RParenLoc);
ExprResult
- BuildCallToObjectOfClassType(Expr *Object, SourceLocation LParenLoc,
+ BuildCallToObjectOfClassType(Scope *S, Expr *Object, SourceLocation LParenLoc,
Expr **Args, unsigned NumArgs,
SourceLocation *CommaLocs,
SourceLocation RParenLoc);
@@ -643,7 +643,8 @@
ExprResult ActOnDeclarationNameExpr(Scope *S, SourceLocation Loc,
DeclarationName Name,
bool HasTrailingLParen,
- const CXXScopeSpec *SS);
+ const CXXScopeSpec *SS,
+ bool ForceResolution = false);
virtual ExprResult ActOnPredefinedExpr(SourceLocation Loc,
@@ -681,7 +682,8 @@
/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
/// This provides the location of the left/right parens and a list of comma
/// locations.
- virtual ExprResult ActOnCallExpr(ExprTy *Fn, SourceLocation LParenLoc,
+ virtual ExprResult ActOnCallExpr(Scope *S, ExprTy *Fn,
+ SourceLocation LParenLoc,
ExprTy **Args, unsigned NumArgs,
SourceLocation *CommaLocs,
SourceLocation RParenLoc);
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index e4beb74..cdca682 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -364,10 +364,29 @@
/// function call context. LookupCtx is only used for a C++
/// qualified-id (foo::bar) to indicate the class or namespace that
/// the identifier must be a member of.
+///
+/// If ForceResolution is true, then we will attempt to resolve the
+/// name even if it looks like a dependent name. This option is off by
+/// default.
Sema::ExprResult Sema::ActOnDeclarationNameExpr(Scope *S, SourceLocation Loc,
DeclarationName Name,
bool HasTrailingLParen,
- const CXXScopeSpec *SS) {
+ const CXXScopeSpec *SS,
+ bool ForceResolution) {
+ if (S->getTemplateParamParent() && Name.getAsIdentifierInfo() &&
+ HasTrailingLParen && !SS && !ForceResolution) {
+ // We've seen something of the form
+ // identifier(
+ // and we are in a template, so it is likely that 's' is a
+ // dependent name. However, we won't know until we've parsed all
+ // of the call arguments. So, build a CXXDependentNameExpr node
+ // to represent this name. Then, if it turns out that none of the
+ // arguments are type-dependent, we'll force the resolution of the
+ // dependent name at that point.
+ return new CXXDependentNameExpr(Name.getAsIdentifierInfo(),
+ Context.DependentTy, Loc);
+ }
+
// Could be enum-constant, value decl, instance variable, etc.
Decl *D;
if (SS && !SS->isEmpty()) {
@@ -377,7 +396,7 @@
D = LookupDecl(Name, Decl::IDNS_Ordinary, S, DC);
} else
D = LookupDecl(Name, Decl::IDNS_Ordinary, S);
-
+
// If this reference is in an Objective-C method, then ivar lookup happens as
// well.
IdentifierInfo *II = Name.getAsIdentifierInfo();
@@ -1315,7 +1334,7 @@
/// This provides the location of the left/right parens and a list of comma
/// locations.
Action::ExprResult Sema::
-ActOnCallExpr(ExprTy *fn, SourceLocation LParenLoc,
+ActOnCallExpr(Scope *S, ExprTy *fn, SourceLocation LParenLoc,
ExprTy **args, unsigned NumArgs,
SourceLocation *CommaLocs, SourceLocation RParenLoc) {
Expr *Fn = static_cast<Expr *>(fn);
@@ -1324,9 +1343,36 @@
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.
+ bool Dependent = false;
+ if (Fn->isTypeDependent()) {
+ if (CXXDependentNameExpr *FnName = dyn_cast<CXXDependentNameExpr>(Fn)) {
+ if (Expr::hasAnyTypeDependentArguments(Args, NumArgs))
+ Dependent = true;
+ else {
+ // Resolve the CXXDependentNameExpr to an actual identifier;
+ // it wasn't really a dependent name after all.
+ ExprResult Resolved
+ = ActOnDeclarationNameExpr(S, FnName->getLocation(), FnName->getName(),
+ /*HasTrailingLParen=*/true,
+ /*SS=*/0,
+ /*ForceResolution=*/true);
+ if (Resolved.isInvalid)
+ return true;
+ else {
+ delete Fn;
+ Fn = (Expr *)Resolved.Val;
+ }
+ }
+ } else
+ Dependent = true;
+ } else
+ Dependent = Expr::hasAnyTypeDependentArguments(Args, NumArgs);
+
// FIXME: Will need to cache the results of name lookup (including
// ADL) in Fn.
- if (Fn->isTypeDependent() || Expr::hasAnyTypeDependentArguments(Args, NumArgs))
+ if (Dependent)
return new CallExpr(Fn, Args, NumArgs, Context.DependentTy, RParenLoc);
// If we're directly calling a function or a set of overloaded
@@ -1358,7 +1404,7 @@
}
if (getLangOptions().CPlusPlus && Fn->getType()->isRecordType())
- return BuildCallToObjectOfClassType(Fn, LParenLoc, Args, NumArgs,
+ return BuildCallToObjectOfClassType(S, Fn, LParenLoc, Args, NumArgs,
CommaLocs, RParenLoc);
// Promote the function operand.
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 80bb9ed..8a68d5b 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -3102,7 +3102,8 @@
/// overloaded function call operator (@c operator()) or performing a
/// user-defined conversion on the object argument.
Action::ExprResult
-Sema::BuildCallToObjectOfClassType(Expr *Object, SourceLocation LParenLoc,
+Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object,
+ SourceLocation LParenLoc,
Expr **Args, unsigned NumArgs,
SourceLocation *CommaLocs,
SourceLocation RParenLoc) {
@@ -3220,7 +3221,7 @@
ImpCastExprToType(Object,
Conv->getConversionType().getNonReferenceType(),
Conv->getConversionType()->isReferenceType());
- return ActOnCallExpr((ExprTy*)Object, LParenLoc, (ExprTy**)Args, NumArgs,
+ return ActOnCallExpr(S, (ExprTy*)Object, LParenLoc, (ExprTy**)Args, NumArgs,
CommaLocs, RParenLoc);
}