r285823 - Add a note that points to the linkage specifier for the C++ linkage errors
Alex Lorenz via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 2 08:46:35 PDT 2016
Author: arphaman
Date: Wed Nov 2 10:46:34 2016
New Revision: 285823
URL: http://llvm.org/viewvc/llvm-project?rev=285823&view=rev
Log:
Add a note that points to the linkage specifier for the C++ linkage errors
This commit improves the "must have C++ linkage" error diagnostics that are
emitted for C++ declarations like templates and literal operators by adding an
additional note that points to the appropriate extern "C" linkage specifier.
rdar://19021120
Differential Revision: https://reviews.llvm.org/D26189
Modified:
cfe/trunk/include/clang/AST/DeclBase.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/AST/DeclBase.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaDeclCXX.cpp
cfe/trunk/lib/Sema/SemaTemplate.cpp
cfe/trunk/test/CXX/over/over.oper/over.literal/p6.cpp
cfe/trunk/test/SemaCXX/cxx0x-defaulted-functions.cpp
cfe/trunk/test/SemaTemplate/class-template-decl.cpp
Modified: cfe/trunk/include/clang/AST/DeclBase.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclBase.h?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclBase.h (original)
+++ cfe/trunk/include/clang/AST/DeclBase.h Wed Nov 2 10:46:34 2016
@@ -1334,6 +1334,9 @@ public:
/// linkage specification context that specifies C linkage.
bool isExternCContext() const;
+ /// \brief Retrieve the nearest enclosing C linkage specification context.
+ const LinkageSpecDecl *getExternCContext() const;
+
/// \brief Determines whether this context or some of its ancestors is a
/// linkage specification context that specifies C++ linkage.
bool isExternCXXContext() const;
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Nov 2 10:46:34 2016
@@ -4502,6 +4502,8 @@ def err_extern_c_global_conflict : Error
"conflicts with declaration %select{in global scope|with C language linkage}0">;
def note_extern_c_global_conflict : Note<
"declared %select{in global scope|with C language linkage}0 here">;
+def note_extern_c_begins_here : Note<
+ "extern \"C\" language linkage specification begins here">;
def warn_weak_import : Warning <
"an already-declared variable is made a weak_import declaration %0">;
def ext_static_non_static : Extension<
@@ -8605,8 +8607,6 @@ def ext_module_import_in_extern_c : ExtW
"import of C++ module '%0' appears within extern \"C\" language linkage "
"specification">, DefaultError,
InGroup<DiagGroup<"module-import-in-extern-c">>;
-def note_module_import_in_extern_c : Note<
- "extern \"C\" language linkage specification begins here">;
def err_module_import_not_at_top_level_fatal : Error<
"import of module '%0' appears within %1">, DefaultFatal;
def ext_module_import_not_at_top_level_noop : ExtWarn<
Modified: cfe/trunk/lib/AST/DeclBase.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclBase.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/lib/AST/DeclBase.cpp (original)
+++ cfe/trunk/lib/AST/DeclBase.cpp Wed Nov 2 10:46:34 2016
@@ -992,6 +992,18 @@ bool DeclContext::isExternCContext() con
return isLinkageSpecContext(this, clang::LinkageSpecDecl::lang_c);
}
+const LinkageSpecDecl *DeclContext::getExternCContext() const {
+ const DeclContext *DC = this;
+ while (DC->getDeclKind() != Decl::TranslationUnit) {
+ if (DC->getDeclKind() == Decl::LinkageSpec &&
+ cast<LinkageSpecDecl>(DC)->getLanguage() ==
+ clang::LinkageSpecDecl::lang_c)
+ return cast<LinkageSpecDecl>(DC);
+ DC = DC->getLexicalParent();
+ }
+ return nullptr;
+}
+
bool DeclContext::isExternCXXContext() const {
return isLinkageSpecContext(this, clang::LinkageSpecDecl::lang_cxx);
}
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Nov 2 10:46:34 2016
@@ -15341,7 +15341,7 @@ static void checkModuleImportContext(Sem
} else if (!M->IsExternC && ExternCLoc.isValid()) {
S.Diag(ImportLoc, diag::ext_module_import_in_extern_c)
<< M->getFullModuleName();
- S.Diag(ExternCLoc, diag::note_module_import_in_extern_c);
+ S.Diag(ExternCLoc, diag::note_extern_c_begins_here);
}
}
Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Wed Nov 2 10:46:34 2016
@@ -12757,6 +12757,9 @@ bool Sema::CheckLiteralOperatorDeclarati
if (FnDecl->isExternC()) {
Diag(FnDecl->getLocation(), diag::err_literal_operator_extern_c);
+ if (const LinkageSpecDecl *LSD =
+ FnDecl->getDeclContext()->getExternCContext())
+ Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
return true;
}
Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplate.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplate.cpp Wed Nov 2 10:46:34 2016
@@ -5939,9 +5939,13 @@ Sema::CheckTemplateDeclScope(Scope *S, T
// C++ [temp]p4:
// A template [...] shall not have C linkage.
DeclContext *Ctx = S->getEntity();
- if (Ctx && Ctx->isExternCContext())
- return Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
- << TemplateParams->getSourceRange();
+ if (Ctx && Ctx->isExternCContext()) {
+ Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
+ << TemplateParams->getSourceRange();
+ if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
+ Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
+ return true;
+ }
Ctx = Ctx->getRedeclContext();
// C++ [temp]p2:
Modified: cfe/trunk/test/CXX/over/over.oper/over.literal/p6.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/over/over.oper/over.literal/p6.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/test/CXX/over/over.oper/over.literal/p6.cpp (original)
+++ cfe/trunk/test/CXX/over/over.oper/over.literal/p6.cpp Wed Nov 2 10:46:34 2016
@@ -1,9 +1,11 @@
// RUN: %clang_cc1 -std=c++11 %s -verify
+// expected-note at +1 {{extern "C" language linkage specification begins here}}
extern "C" void operator "" _a(const char *); // expected-error {{must have C++ linkage}}
extern "C" template<char...> void operator "" _b(); // expected-error {{must have C++ linkage}}
+// expected-note at -1 {{extern "C" language linkage specification begins here}}
-extern "C" {
+extern "C" { // expected-note 4 {{extern "C" language linkage specification begins here}}
void operator "" _c(const char *); // expected-error {{must have C++ linkage}}
template<char...> void operator "" _d(); // expected-error {{must have C++ linkage}}
namespace N {
Modified: cfe/trunk/test/SemaCXX/cxx0x-defaulted-functions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx0x-defaulted-functions.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx0x-defaulted-functions.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx0x-defaulted-functions.cpp Wed Nov 2 10:46:34 2016
@@ -180,7 +180,7 @@ namespace PR14577 {
Outer<T>::Inner2<T>::~Inner2() = default; // expected-error {{nested name specifier 'Outer<T>::Inner2<T>::' for declaration does not refer into a class, class template or class template partial specialization}} expected-error {{only special member functions may be defaulted}}
}
-extern "C" {
+extern "C" { // expected-note {{extern "C" language linkage specification begins here}}
template<typename _Tp> // expected-error {{templates must have C++ linkage}}
void PR13573(const _Tp&) = delete;
}
Modified: cfe/trunk/test/SemaTemplate/class-template-decl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/class-template-decl.cpp?rev=285823&r1=285822&r2=285823&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/class-template-decl.cpp (original)
+++ cfe/trunk/test/SemaTemplate/class-template-decl.cpp Wed Nov 2 10:46:34 2016
@@ -10,11 +10,11 @@ namespace N {
template<typename T> class C;
}
-extern "C" {
+extern "C" { // expected-note {{extern "C" language linkage specification begins here}}
template<typename T> class D; // expected-error{{templates must have C++ linkage}}
}
-extern "C" {
+extern "C" { // expected-note 2 {{extern "C" language linkage specification begins here}}
class PR17968 {
template<typename T> class D; // expected-error{{templates must have C++ linkage}}
template<typename T> void f(); // expected-error{{templates must have C++ linkage}}
@@ -148,7 +148,7 @@ namespace redecl {
}
extern "C" template <typename T> // expected-error{{templates must have C++ linkage}}
-void DontCrashOnThis() {
+void DontCrashOnThis() { // expected-note at -1 {{extern "C" language linkage specification begins here}}
T &pT = T();
pT;
}
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