r313315 - Diagnostic specific failed condition in a static_assert.

Eric Fiselier via cfe-commits cfe-commits at lists.llvm.org
Sun Sep 17 13:58:55 PDT 2017


Fixed in r313499.

/Eric

On Sun, Sep 17, 2017 at 2:04 PM, Eric Fiselier <eric at efcs.ca> wrote:

> I'll correct them.
>
> /Eric
>
> On Sat, Sep 16, 2017 at 6:28 PM, Richard Smith <richard at metafoo.co.uk>
> wrote:
>
>> This is a bug in the libc++ tests. It's OK for them to check that the
>> static_assert message is produced, but not that they're prefixed with the
>> exact string "static_assert failed:".
>>
>> On 16 September 2017 at 05:54, NAKAMURA Takumi via cfe-commits <
>> cfe-commits at lists.llvm.org> wrote:
>>
>>> This triggered failure in libcxx tests.
>>> http://bb.pgr.jp/builders/bootstrap-clang-libcxx-lld-i686-li
>>> nux/builds/97
>>>
>>>
>>> On Fri, Sep 15, 2017 at 8:40 AM Douglas Gregor via cfe-commits <
>>> cfe-commits at lists.llvm.org> wrote:
>>>
>>>> Author: dgregor
>>>> Date: Thu Sep 14 16:38:42 2017
>>>> New Revision: 313315
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=313315&view=rev
>>>> Log:
>>>> Diagnostic specific failed condition in a static_assert.
>>>>
>>>> When a static_assert fails, dig out a specific condition to diagnose,
>>>> using the same logic that we use to find the enable_if condition to
>>>> diagnose.
>>>>
>>>> Modified:
>>>>     cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>>>     cfe/trunk/include/clang/Sema/Sema.h
>>>>     cfe/trunk/lib/Sema/SemaDeclCXX.cpp
>>>>     cfe/trunk/lib/Sema/SemaTemplate.cpp
>>>>     cfe/trunk/test/SemaCXX/static-assert.cpp
>>>>
>>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/
>>>> Basic/DiagnosticSemaKinds.td?rev=313315&r1=313314&r2=313315&view=diff
>>>> ============================================================
>>>> ==================
>>>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Sep 14
>>>> 16:38:42 2017
>>>> @@ -1219,6 +1219,8 @@ def warn_messaging_unqualified_id : Warn
>>>>  def err_static_assert_expression_is_not_constant : Error<
>>>>    "static_assert expression is not an integral constant expression">;
>>>>  def err_static_assert_failed : Error<"static_assert failed%select{
>>>> %1|}0">;
>>>> +def err_static_assert_requirement_failed : Error<
>>>> +  "static_assert failed due to requirement '%0'%select{ %2|}1">;
>>>>  def ext_static_assert_no_message : ExtWarn<
>>>>    "static_assert with no message is a C++17 extension">,
>>>> InGroup<CXX17>;
>>>>  def warn_cxx14_compat_static_assert_no_message : Warning<
>>>>
>>>> Modified: cfe/trunk/include/clang/Sema/Sema.h
>>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/
>>>> Sema/Sema.h?rev=313315&r1=313314&r2=313315&view=diff
>>>> ============================================================
>>>> ==================
>>>> --- cfe/trunk/include/clang/Sema/Sema.h (original)
>>>> +++ cfe/trunk/include/clang/Sema/Sema.h Thu Sep 14 16:38:42 2017
>>>> @@ -2783,6 +2783,14 @@ public:
>>>>    EnableIfAttr *CheckEnableIf(FunctionDecl *Function, ArrayRef<Expr *>
>>>> Args,
>>>>                                bool MissingImplicitThis = false);
>>>>
>>>> +  /// Find the failed Boolean condition within a given Boolean
>>>> +  /// constant expression, and describe it with a string.
>>>> +  ///
>>>> +  /// \param AllowTopLevelCond Whether to allow the result to be the
>>>> +  /// complete top-level condition.
>>>> +  std::pair<Expr *, std::string>
>>>> +  findFailedBooleanCondition(Expr *Cond, bool AllowTopLevelCond);
>>>> +
>>>>    /// Emit diagnostics for the diagnose_if attributes on Function,
>>>> ignoring any
>>>>    /// non-ArgDependent DiagnoseIfAttrs.
>>>>    ///
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaD
>>>> eclCXX.cpp?rev=313315&r1=313314&r2=313315&view=diff
>>>> ============================================================
>>>> ==================
>>>> --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Thu Sep 14 16:38:42 2017
>>>> @@ -13296,8 +13296,20 @@ Decl *Sema::BuildStaticAssertDeclaration
>>>>        llvm::raw_svector_ostream Msg(MsgBuffer);
>>>>        if (AssertMessage)
>>>>          AssertMessage->printPretty(Msg, nullptr, getPrintingPolicy());
>>>> -      Diag(StaticAssertLoc, diag::err_static_assert_failed)
>>>> -        << !AssertMessage << Msg.str() << AssertExpr->getSourceRange();
>>>> +
>>>> +      Expr *InnerCond = nullptr;
>>>> +      std::string InnerCondDescription;
>>>> +      std::tie(InnerCond, InnerCondDescription) =
>>>> +        findFailedBooleanCondition(Converted.get(),
>>>> +                                   /*AllowTopLevelCond=*/false);
>>>> +      if (InnerCond) {
>>>> +        Diag(StaticAssertLoc, diag::err_static_assert_requir
>>>> ement_failed)
>>>> +          << InnerCondDescription << !AssertMessage
>>>> +          << Msg.str() << InnerCond->getSourceRange();
>>>> +      } else {
>>>> +        Diag(StaticAssertLoc, diag::err_static_assert_failed)
>>>> +          << !AssertMessage << Msg.str() <<
>>>> AssertExpr->getSourceRange();
>>>> +      }
>>>>        Failed = true;
>>>>      }
>>>>    }
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaT
>>>> emplate.cpp?rev=313315&r1=313314&r2=313315&view=diff
>>>> ============================================================
>>>> ==================
>>>> --- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaTemplate.cpp Thu Sep 14 16:38:42 2017
>>>> @@ -2863,11 +2863,9 @@ static Expr *lookThroughRangesV3Conditio
>>>>    return Cond;
>>>>  }
>>>>
>>>> -/// Find the failed subexpression within enable_if, and describe it
>>>> -/// with a string.
>>>> -static std::pair<Expr *, std::string>
>>>> -findFailedEnableIfCondition(Sema &S, Expr *Cond) {
>>>> -  Cond = lookThroughRangesV3Condition(S.PP, Cond);
>>>> +std::pair<Expr *, std::string>
>>>> +Sema::findFailedBooleanCondition(Expr *Cond, bool AllowTopLevelCond) {
>>>> +  Cond = lookThroughRangesV3Condition(PP, Cond);
>>>>
>>>>    // Separate out all of the terms in a conjunction.
>>>>    SmallVector<Expr *, 4> Terms;
>>>> @@ -2876,27 +2874,37 @@ findFailedEnableIfCondition(Sema &S, Exp
>>>>    // Determine which term failed.
>>>>    Expr *FailedCond = nullptr;
>>>>    for (Expr *Term : Terms) {
>>>> +    Expr *TermAsWritten = Term->IgnoreParenImpCasts();
>>>> +
>>>> +    // Literals are uninteresting.
>>>> +    if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
>>>> +        isa<IntegerLiteral>(TermAsWritten))
>>>> +      continue;
>>>> +
>>>>      // The initialization of the parameter from the argument is
>>>>      // a constant-evaluated context.
>>>>      EnterExpressionEvaluationContext ConstantEvaluated(
>>>> -      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
>>>> +      *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
>>>>
>>>>      bool Succeeded;
>>>> -    if (Term->EvaluateAsBooleanCondition(Succeeded, S.Context) &&
>>>> +    if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
>>>>          !Succeeded) {
>>>> -      FailedCond = Term->IgnoreParenImpCasts();
>>>> +      FailedCond = TermAsWritten;
>>>>        break;
>>>>      }
>>>>    }
>>>>
>>>> -  if (!FailedCond)
>>>> +  if (!FailedCond) {
>>>> +    if (!AllowTopLevelCond)
>>>> +      return { nullptr, "" };
>>>> +
>>>>      FailedCond = Cond->IgnoreParenImpCasts();
>>>> +  }
>>>>
>>>>    std::string Description;
>>>>    {
>>>>      llvm::raw_string_ostream Out(Description);
>>>> -    FailedCond->printPretty(Out, nullptr,
>>>> -                            PrintingPolicy(S.Context.getLangOpts()));
>>>> +    FailedCond->printPretty(Out, nullptr, getPrintingPolicy());
>>>>    }
>>>>    return { FailedCond, Description };
>>>>  }
>>>> @@ -2980,8 +2988,9 @@ QualType Sema::CheckTemplateIdType(Templ
>>>>              Expr *FailedCond;
>>>>              std::string FailedDescription;
>>>>              std::tie(FailedCond, FailedDescription) =
>>>> -              findFailedEnableIfCondition(
>>>> -                *this, TemplateArgs[0].getSourceExpression());
>>>> +              findFailedBooleanCondition(
>>>> +                TemplateArgs[0].getSourceExpression(),
>>>> +                /*AllowTopLevelCond=*/true);
>>>>
>>>>              // Remove the old SFINAE diagnostic.
>>>>              PartialDiagnosticAt OldDiag =
>>>> @@ -9513,7 +9522,7 @@ Sema::CheckTypenameType(ElaboratedTypeKe
>>>>          Expr *FailedCond;
>>>>          std::string FailedDescription;
>>>>          std::tie(FailedCond, FailedDescription) =
>>>> -          findFailedEnableIfCondition(*this, Cond);
>>>> +          findFailedBooleanCondition(Cond,
>>>> /*AllowTopLevelCond=*/true);
>>>>
>>>>          Diag(FailedCond->getExprLoc(),
>>>>               diag::err_typename_nested_not_found_requirement)
>>>>
>>>> Modified: cfe/trunk/test/SemaCXX/static-assert.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/s
>>>> tatic-assert.cpp?rev=313315&r1=313314&r2=313315&view=diff
>>>> ============================================================
>>>> ==================
>>>> --- cfe/trunk/test/SemaCXX/static-assert.cpp (original)
>>>> +++ cfe/trunk/test/SemaCXX/static-assert.cpp Thu Sep 14 16:38:42 2017
>>>> @@ -51,3 +51,20 @@ StaticAssertProtected<X> sap2; // expect
>>>>
>>>>  static_assert(true); // expected-warning {{C++17 extension}}
>>>>  static_assert(false); // expected-error-re {{failed{{$}}}}
>>>> expected-warning {{extension}}
>>>> +
>>>> +
>>>> +// Diagnostics for static_assert with multiple conditions
>>>> +template<typename T> struct first_trait {
>>>> +  static const bool value = false;
>>>> +};
>>>> +
>>>> +template<>
>>>> +struct first_trait<X> {
>>>> +  static const bool value = true;
>>>> +};
>>>> +
>>>> +template<typename T> struct second_trait {
>>>> +  static const bool value = false;
>>>> +};
>>>> +
>>>> +static_assert(first_trait<X>::value && second_trait<X>::value,
>>>> "message"); // expected-error{{static_assert failed due to requirement
>>>> 'second_trait<X>::value' "message"}}
>>>>
>>>>
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>>>
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>>
>
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