Finished semantic analysis of non-type template arguments, to check
for non-external names whose address becomes the template
argument. This completes C++ [temp.arg.nontype]p1.
Note that our interpretation of C++ [temp.arg.nontype]p1b3 differs
from EDG's interpretation (we're stricter, and GCC agrees with
us). They're opening a core issue about the matter.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64317 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 429dc8e..1c2484d 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -14,6 +14,7 @@
#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Basic/LangOptions.h"
@@ -825,6 +826,158 @@
return false;
}
+/// \brief Checks whether the given template argument is the address
+/// of an object or function according to C++ [temp.arg.nontype]p1.
+bool Sema::CheckTemplateArgumentAddressOfObjectOrFunction(Expr *Arg) {
+ bool Invalid = false;
+
+ // See through any implicit casts we added to fix the type.
+ if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(Arg))
+ Arg = Cast->getSubExpr();
+
+ // C++ [temp.arg.nontype]p1:
+ //
+ // A template-argument for a non-type, non-template
+ // template-parameter shall be one of: [...]
+ //
+ // -- the address of an object or function with external
+ // linkage, including function templates and function
+ // template-ids but excluding non-static class members,
+ // expressed as & id-expression where the & is optional if
+ // the name refers to a function or array, or if the
+ // corresponding template-parameter is a reference; or
+ DeclRefExpr *DRE = 0;
+
+ // Ignore (and complain about) any excess parentheses.
+ while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
+ if (!Invalid) {
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_extra_parens)
+ << Arg->getSourceRange();
+ Invalid = true;
+ }
+
+ Arg = Parens->getSubExpr();
+ }
+
+ if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
+ if (UnOp->getOpcode() == UnaryOperator::AddrOf)
+ DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
+ } else
+ DRE = dyn_cast<DeclRefExpr>(Arg);
+
+ if (!DRE || !isa<ValueDecl>(DRE->getDecl()))
+ return Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_not_object_or_func_form)
+ << Arg->getSourceRange();
+
+ // Cannot refer to non-static data members
+ if (FieldDecl *Field = dyn_cast<FieldDecl>(DRE->getDecl()))
+ return Diag(Arg->getSourceRange().getBegin(), diag::err_template_arg_field)
+ << Field << Arg->getSourceRange();
+
+ // Cannot refer to non-static member functions
+ if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(DRE->getDecl()))
+ if (!Method->isStatic())
+ return Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_method)
+ << Method << Arg->getSourceRange();
+
+ // Functions must have external linkage.
+ if (FunctionDecl *Func = dyn_cast<FunctionDecl>(DRE->getDecl())) {
+ if (Func->getStorageClass() == FunctionDecl::Static) {
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_function_not_extern)
+ << Func << Arg->getSourceRange();
+ Diag(Func->getLocation(), diag::note_template_arg_internal_object)
+ << true;
+ return true;
+ }
+
+ // Okay: we've named a function with external linkage.
+ return Invalid;
+ }
+
+ if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
+ if (!Var->hasGlobalStorage()) {
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_object_not_extern)
+ << Var << Arg->getSourceRange();
+ Diag(Var->getLocation(), diag::note_template_arg_internal_object)
+ << true;
+ return true;
+ }
+
+ // Okay: we've named an object with external linkage
+ return Invalid;
+ }
+
+ // We found something else, but we don't know specifically what it is.
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_not_object_or_func)
+ << Arg->getSourceRange();
+ Diag(DRE->getDecl()->getLocation(),
+ diag::note_template_arg_refers_here);
+ return true;
+}
+
+/// \brief Checks whether the given template argument is a pointer to
+/// member constant according to C++ [temp.arg.nontype]p1.
+bool Sema::CheckTemplateArgumentPointerToMember(Expr *Arg) {
+ bool Invalid = false;
+
+ // See through any implicit casts we added to fix the type.
+ if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(Arg))
+ Arg = Cast->getSubExpr();
+
+ // C++ [temp.arg.nontype]p1:
+ //
+ // A template-argument for a non-type, non-template
+ // template-parameter shall be one of: [...]
+ //
+ // -- a pointer to member expressed as described in 5.3.1.
+ QualifiedDeclRefExpr *DRE = 0;
+
+ // Ignore (and complain about) any excess parentheses.
+ while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
+ if (!Invalid) {
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_extra_parens)
+ << Arg->getSourceRange();
+ Invalid = true;
+ }
+
+ Arg = Parens->getSubExpr();
+ }
+
+ if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg))
+ if (UnOp->getOpcode() == UnaryOperator::AddrOf)
+ DRE = dyn_cast<QualifiedDeclRefExpr>(UnOp->getSubExpr());
+
+ if (!DRE)
+ return Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_not_pointer_to_member_form)
+ << Arg->getSourceRange();
+
+ if (isa<FieldDecl>(DRE->getDecl()) || isa<CXXMethodDecl>(DRE->getDecl())) {
+ assert((isa<FieldDecl>(DRE->getDecl()) ||
+ !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
+ "Only non-static member pointers can make it here");
+
+ // Okay: this is the address of a non-static member, and therefore
+ // a member pointer constant.
+ return Invalid;
+ }
+
+ // We found something else, but we don't know specifically what it is.
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::err_template_arg_not_pointer_to_member_form)
+ << Arg->getSourceRange();
+ Diag(DRE->getDecl()->getLocation(),
+ diag::note_template_arg_refers_here);
+ return true;
+}
+
/// \brief Check a template argument against its corresponding
/// non-type template parameter.
///
@@ -921,7 +1074,8 @@
(ParamType->isMemberPointerType() &&
ParamType->getAsMemberPointerType()->getPointeeType()
->isFunctionType())) {
- if (Context.hasSameUnqualifiedType(ArgType, ParamType.getNonReferenceType())) {
+ if (Context.hasSameUnqualifiedType(ArgType,
+ ParamType.getNonReferenceType())) {
// We don't have to do anything: the types already match.
} else if (ArgType->isFunctionType() && ParamType->isPointerType()) {
ArgType = Context.getPointerType(ArgType);
@@ -936,7 +1090,8 @@
}
}
- if (!Context.hasSameUnqualifiedType(ArgType, ParamType.getNonReferenceType())) {
+ if (!Context.hasSameUnqualifiedType(ArgType,
+ ParamType.getNonReferenceType())) {
// We can't perform this conversion.
Diag(Arg->getSourceRange().getBegin(),
diag::err_template_arg_not_convertible)
@@ -944,9 +1099,11 @@
Diag(Param->getLocation(), diag::note_template_param_here);
return true;
}
-
- // FIXME: Check the restrictions in p1!
- return false;
+
+ if (ParamType->isMemberPointerType())
+ return CheckTemplateArgumentPointerToMember(Arg);
+
+ return CheckTemplateArgumentAddressOfObjectOrFunction(Arg);
}
if (const PointerType *ParamPtrType = ParamType->getAsPointerType()) {
@@ -975,8 +1132,7 @@
return true;
}
- // FIXME: Check the restrictions in p1!
- return false;
+ return CheckTemplateArgumentAddressOfObjectOrFunction(Arg);
}
if (const ReferenceType *ParamRefType = ParamType->getAsReferenceType()) {
@@ -1011,10 +1167,7 @@
return true;
}
- // FIXME: Check the restrictions in p1!
- // CheckAddressConstantExpression(Lvalue) can be modified to do
- // this.
- return false;
+ return CheckTemplateArgumentAddressOfObjectOrFunction(Arg);
}
// -- For a non-type template-parameter of type pointer to data
@@ -1034,9 +1187,7 @@
return true;
}
- // FIXME: Check the restrictions in p1.
-
- return false;
+ return CheckTemplateArgumentPointerToMember(Arg);
}
/// \brief Check a template argument against its corresponding
@@ -1059,7 +1210,8 @@
if (!isa<ClassTemplateDecl>(Template)) {
assert(isa<FunctionTemplateDecl>(Template) &&
"Only function templates are possible here");
- Diag(Arg->getSourceRange().getBegin(), diag::note_template_arg_refers_here)
+ Diag(Arg->getSourceRange().getBegin(),
+ diag::note_template_arg_refers_here_func)
<< Template;
}