Revert "[Sema] Warn on attribute nothrow conflicting with language specifiers"

This reverts r314461.

It is warning on user code that uses END_COM_MAP(), which expands to
declare QueryInterface with conflicting exception specifers. I've spent
a while trying to understand why, but haven't been able to extract a
reduced test case. Let's revert and I'll keep trying.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314689 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 1 insertions, 48 deletions

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 38f2a3bd65..3d20cab8d7 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1419,10 +1419,6 @@ def err_noexcept_needs_constant_expression : Error<
   "argument to noexcept specifier must be a constant expression">;
 def err_exception_spec_not_parsed : Error<
   "exception specification is not available until end of class definition">;
-def warn_nothrow_attr_disagrees_with_exception_specification
-    : ExtWarn<"attribute 'nothrow' ignored due to conflicting exception "
-              "specification">,
-      InGroup<IgnoredAttributes>;
 
 // C++ access checking
 def err_class_redeclared_with_different_access : Error<
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 2a13c9576c..1f4be4405b 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1985,25 +1985,6 @@ static void handleNoReturnAttr(Sema &S, Decl *D, const AttributeList &Attrs) {
       Attrs.getRange(), S.Context, Attrs.getAttributeSpellingListIndex()));
 }
 
-static void handleNoThrowAttr(Sema &S, Decl *D, const AttributeList &Attrs) {
-  assert(isa<FunctionDecl>(D) && "attribute nothrow only valid on functions");
-
-  auto *FD = cast<FunctionDecl>(D);
-  const auto *FPT = FD->getType()->getAs<FunctionProtoType>();
-
-  if (FPT && FPT->hasExceptionSpec() &&
-      FPT->getExceptionSpecType() != EST_BasicNoexcept) {
-    S.Diag(Attrs.getLoc(),
-           diag::warn_nothrow_attr_disagrees_with_exception_specification);
-    S.Diag(FD->getExceptionSpecSourceRange().getBegin(),
-           diag::note_previous_decl)
-        << "exception specification";
-  }
-
-  D->addAttr(::new (S.Context) NoThrowAttr(
-      Attrs.getRange(), S.Context, Attrs.getAttributeSpellingListIndex()));
-}
-
 static void handleNoCallerSavedRegsAttr(Sema &S, Decl *D,
                                         const AttributeList &Attr) {
   if (S.CheckNoCallerSavedRegsAttr(Attr))
@@ -6230,7 +6211,7 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
     handleNoReturnAttr(S, D, Attr);
     break;
   case AttributeList::AT_NoThrow:
-    handleNoThrowAttr(S, D, Attr);
+    handleSimpleAttribute<NoThrowAttr>(S, D, Attr);
     break;
   case AttributeList::AT_CUDAShared:
     handleSharedAttr(S, D, Attr);
diff --git a/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp b/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp
deleted file mode 100644
index c927c4f926..0000000000
--- a/test/SemaCXX/warn-conflicting-nothrow-attr-exception-spec.cpp
+++ /dev/null
@@ -1,24 +0,0 @@
-// RUN: %clang_cc1 %s -fcxx-exceptions -fsyntax-only -Wexceptions -verify -std=c++14
-
-struct S {
-  //expected-warning@+2 {{attribute 'nothrow' ignored due to conflicting exception specification}}
-  //expected-note@+1 {{exception specification declared here}}
-  __attribute__((nothrow)) S() noexcept(true);
-  //expected-warning@+2 {{attribute 'nothrow' ignored due to conflicting exception specification}}
-  //expected-note@+1 {{exception specification declared here}}
-  __attribute__((nothrow)) void Func1() noexcept(false);
-  __attribute__((nothrow)) void Func3() noexcept;
-};
-
-void throwing() noexcept(false);
-void non_throwing(bool b = true) noexcept;
-
-template <typename Fn>
-struct T {
-    __attribute__((nothrow)) void f(Fn) noexcept(Fn());
-};
-
-//expected-warning@-3 {{attribute 'nothrow' ignored due to conflicting exception specification}}
-//expected-note@-4 {{exception specification declared here}}
-template struct T<decltype(throwing)>;
-template struct T<decltype(non_throwing)>;