r262881 - P0188R1: add support for standard [[fallthrough]] attribute. This is almost

Nico Weber via cfe-commits cfe-commits at lists.llvm.org
Wed Mar 9 15:44:55 PST 2016


On Tue, Mar 8, 2016 at 12:18 PM, Nico Weber <thakis at chromium.org> wrote:

> On Tue, Mar 8, 2016 at 2:10 PM, Richard Smith <richard at metafoo.co.uk>
> wrote:
>
>> On Tue, Mar 8, 2016 at 11:04 AM, Nico Weber <thakis at chromium.org> wrote:
>> > On Tue, Mar 8, 2016 at 1:49 PM, Richard Smith <richard at metafoo.co.uk>
>> wrote:
>> >>
>> >> On Tue, Mar 8, 2016 at 9:05 AM, Nico Weber <thakis at chromium.org>
>> wrote:
>> >> > This causes clang to warn on
>> >> >
>> >> >   default: assert (false); HB_FALLTHROUGH;
>> >>
>> >> What follows this? (A case label?) What warning is being produced?
>> >
>> >
>> > A case label. Full snippet:
>> >
>> https://code.google.com/p/chromium/codesearch#chromium/src/third_party/harfbuzz-ng/src/hb-ot-shape-complex-thai.cc&l=142
>> >
>> > Full warning (from
>> >
>> https://build.chromium.org/p/chromium.fyi/builders/ClangToTMac%20%28dbg%29/builds/4497/steps/compile/logs/stdio
>> ):
>> >
>> > ../../third_party/harfbuzz-ng/src/hb-ot-shape-complex-thai.cc:142:30:
>> error:
>> > fallthrough annotation in unreachable code
>> [-Werror,-Wimplicit-fallthrough]
>> >     default: assert (false); HB_FALLTHROUGH;
>> >                              ^
>> > ../../third_party/harfbuzz-ng/src/hb-private.hh:140:26: note: expanded
>> from
>> > macro 'HB_FALLTHROUGH'
>> > #  define HB_FALLTHROUGH [[clang::fallthrough]]
>> >
>> > As far as I know, we don't opt in to -Wimplicit-fallthrough (and I
>> don't see
>> > a flag on the commandline of the failing compile; also available at the
>> > above link.)
>>
>> OK, I see what's going wrong. Half of -Wimplicit-fallthrough is off by
>> default, half of it is on by default. We used to do the CFG-based
>> analysis only if the warning was enabled (because otherwise it would
>> never produce any messages), and this change makes us also do the
>> analysis when the warning is disabled but there are [[fallthrough]];
>> statements in the function (it promotes the "misplaced
>> [[fallthrough]];" diagnostic from warning to error, so we need the
>> analysis if the attribute is present). This change should have had no
>> impact on -Wimplicit-fallthrough (either the warning was disabled so
>> no diagnostics are produced before and after, or the warning was
>> enabled so the same diagnostics are produced before and after), but
>> apparently when we ask "is this warning enabled?" and the warning
>> group contains multiple diagnostics, we don't check them all...
>>
>> There's an easy fix for clang: warn_fallthrough_attr_unreachable
>> should be marked DefaultIgnore.
>
>
> Sounds good. Are you doing that? Want me to do that?
>

^ ping


>
>
>> (Though that chromium code would still
>> produce diagnostics -- with or without this change -- if you build
>> with -Wimplicit-fallthrough and -DNDEBUG, so maybe you do need a
>> different macro for that case regardless.)
>>
>> >> > The fallthrough needs to be there for release builds, but now it must
>> >> > not be
>> >> > there for debug builds. I suppose this means projects now need an
>> >> > UNREACHED_CASE macro that expands to assert(false) in debug and to
>> >> > fallthrough in release (with clang; and to something else with other
>> >> > compilers)?
>> >> >
>> >> > On Mon, Mar 7, 2016 at 7:32 PM, Richard Smith via cfe-commits
>> >> > <cfe-commits at lists.llvm.org> wrote:
>> >> >>
>> >> >> Author: rsmith
>> >> >> Date: Mon Mar  7 18:32:55 2016
>> >> >> New Revision: 262881
>> >> >>
>> >> >> URL: http://llvm.org/viewvc/llvm-project?rev=262881&view=rev
>> >> >> Log:
>> >> >> P0188R1: add support for standard [[fallthrough]] attribute. This is
>> >> >> almost
>> >> >> exactly the same as clang's existing [[clang::fallthrough]]
>> attribute,
>> >> >> which
>> >> >> has been updated to have the same semantics. The one significant
>> >> >> difference
>> >> >> is that [[fallthrough]] is ill-formed if it's not used immediately
>> >> >> before
>> >> >> a
>> >> >> switch label (even when -Wimplicit-fallthrough is disabled). To
>> support
>> >> >> that,
>> >> >> we now build a CFG of any function that uses a '[[fallthrough]];'
>> >> >> statement
>> >> >> to check.
>> >> >>
>> >> >> In passing, fix some bugs with our support for statement attributes
>> --
>> >> >> in
>> >> >> particular, diagnose their use on declarations, rather than
>> asserting.
>> >> >>
>> >> >> Modified:
>> >> >>     cfe/trunk/include/clang/AST/Attr.h
>> >> >>     cfe/trunk/include/clang/Basic/Attr.td
>> >> >>     cfe/trunk/include/clang/Basic/AttrDocs.td
>> >> >>     cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> >> >>     cfe/trunk/include/clang/Sema/AttributeList.h
>> >> >>     cfe/trunk/include/clang/Sema/ScopeInfo.h
>> >> >>     cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
>> >> >>     cfe/trunk/lib/Sema/AttributeList.cpp
>> >> >>     cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>> >> >>     cfe/trunk/lib/Sema/SemaStmtAttr.cpp
>> >> >>     cfe/trunk/test/Analysis/cxx11-crashes.cpp
>> >> >>     cfe/trunk/test/PCH/Inputs/cxx11-statement-attributes.h
>> >> >>     cfe/trunk/test/PCH/cxx11-statement-attributes.cpp
>> >> >>     cfe/trunk/test/Parser/cxx0x-attributes.cpp
>> >> >>     cfe/trunk/test/SemaCXX/for-range-examples.cpp
>> >> >>     cfe/trunk/test/SemaCXX/generalized-deprecated.cpp
>> >> >>     cfe/trunk/test/SemaCXX/nodiscard.cpp
>> >> >>     cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-macro.cpp
>> >> >>
>>  cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-per-method.cpp
>> >> >>     cfe/trunk/test/SemaCXX/switch-implicit-fallthrough.cpp
>> >> >>     cfe/trunk/utils/TableGen/ClangAttrEmitter.cpp
>> >> >>     cfe/trunk/www/cxx_status.html
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/AST/Attr.h
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Attr.h?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/AST/Attr.h (original)
>> >> >> +++ cfe/trunk/include/clang/AST/Attr.h Mon Mar  7 18:32:55 2016
>> >> >> @@ -118,6 +118,19 @@ public:
>> >> >>    bool duplicatesAllowed() const { return DuplicatesAllowed; }
>> >> >>  };
>> >> >>
>> >> >> +class StmtAttr : public Attr {
>> >> >> +protected:
>> >> >> +  StmtAttr(attr::Kind AK, SourceRange R, unsigned
>> SpellingListIndex,
>> >> >> +                  bool IsLateParsed, bool DuplicatesAllowed)
>> >> >> +      : Attr(AK, R, SpellingListIndex, IsLateParsed,
>> >> >> DuplicatesAllowed)
>> >> >> {}
>> >> >> +
>> >> >> +public:
>> >> >> +  static bool classof(const Attr *A) {
>> >> >> +    return A->getKind() >= attr::FirstStmtAttr &&
>> >> >> +           A->getKind() <= attr::LastStmtAttr;
>> >> >> +  }
>> >> >> +};
>> >> >> +
>> >> >>  class InheritableAttr : public Attr {
>> >> >>  protected:
>> >> >>    InheritableAttr(attr::Kind AK, SourceRange R, unsigned
>> >> >> SpellingListIndex,
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/Basic/Attr.td
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/Basic/Attr.td (original)
>> >> >> +++ cfe/trunk/include/clang/Basic/Attr.td Mon Mar  7 18:32:55 2016
>> >> >> @@ -311,6 +311,9 @@ class TypeAttr : Attr {
>> >> >>    let ASTNode = 0;
>> >> >>  }
>> >> >>
>> >> >> +/// A stmt attribute is not processed on a declaration or a type.
>> >> >> +class StmtAttr : Attr;
>> >> >> +
>> >> >>  /// An inheritable attribute is inherited by later redeclarations.
>> >> >>  class InheritableAttr : Attr;
>> >> >>
>> >> >> @@ -738,8 +741,9 @@ def ExtVectorType : Attr {
>> >> >>    let Documentation = [Undocumented];
>> >> >>  }
>> >> >>
>> >> >> -def FallThrough : Attr {
>> >> >> -  let Spellings = [CXX11<"clang", "fallthrough">];
>> >> >> +def FallThrough : StmtAttr {
>> >> >> +  let Spellings = [CXX11<"", "fallthrough", 201503>,
>> >> >> +                   CXX11<"clang", "fallthrough">];
>> >> >>  //  let Subjects = [NullStmt];
>> >> >>    let Documentation = [FallthroughDocs];
>> >> >>  }
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/Basic/AttrDocs.td
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/AttrDocs.td?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/Basic/AttrDocs.td (original)
>> >> >> +++ cfe/trunk/include/clang/Basic/AttrDocs.td Mon Mar  7 18:32:55
>> 2016
>> >> >> @@ -756,9 +756,10 @@ potentially-evaluated discarded-value ex
>> >> >>
>> >> >>  def FallthroughDocs : Documentation {
>> >> >>    let Category = DocCatStmt;
>> >> >> +  let Heading = "fallthrough, clang::fallthrough";
>> >> >>    let Content = [{
>> >> >> -The ``clang::fallthrough`` attribute is used along with the
>> >> >> -``-Wimplicit-fallthrough`` argument to annotate intentional
>> >> >> fall-through
>> >> >> +The ``fallthrough`` (or ``clang::fallthrough``) attribute is used
>> >> >> +to annotate intentional fall-through
>> >> >>  between switch labels.  It can only be applied to a null statement
>> >> >> placed
>> >> >> at a
>> >> >>  point of execution between any statement and the next switch label.
>> >> >> It
>> >> >> is
>> >> >>  common to mark these places with a specific comment, but this
>> >> >> attribute
>> >> >> is
>> >> >> @@ -769,6 +770,10 @@ control-flow statements like ``break;``,
>> >> >>  where ``break;`` can, but only if there are no statements on the
>> >> >> execution path
>> >> >>  between it and the next switch label.
>> >> >>
>> >> >> +By default, Clang does not warn on unannotated fallthrough from one
>> >> >> ``switch``
>> >> >> +case to another. Diagnostics on fallthrough without a corresponding
>> >> >> annotation
>> >> >> +can be enabled with the ``-Wimplicit-fallthrough`` argument.
>> >> >> +
>> >> >>  Here is an example:
>> >> >>
>> >> >>  .. code-block:: c++
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> >> >> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Mar  7
>> >> >> 18:32:55 2016
>> >> >> @@ -2358,8 +2358,10 @@ def warn_cxx11_gnu_attribute_on_type : W
>> >> >>  def warn_unhandled_ms_attribute_ignored : Warning<
>> >> >>    "__declspec attribute %0 is not supported">,
>> >> >>    InGroup<IgnoredAttributes>;
>> >> >> -def err_attribute_invalid_on_stmt : Error<
>> >> >> +def err_decl_attribute_invalid_on_stmt : Error<
>> >> >>    "%0 attribute cannot be applied to a statement">;
>> >> >> +def err_stmt_attribute_invalid_on_decl : Error<
>> >> >> +  "%0 attribute cannot be applied to a declaration">;
>> >> >>  def warn_declspec_attribute_ignored : Warning<
>> >> >>    "attribute %0 is ignored, place it after "
>> >> >>    "\"%select{class|struct|interface|union|enum}1\" to apply
>> attribute
>> >> >> to
>> >> >> "
>> >> >> @@ -6592,8 +6594,11 @@ def warn_unused_result : Warning<
>> >> >>  def warn_unused_volatile : Warning<
>> >> >>    "expression result unused; assign into a variable to force a
>> >> >> volatile
>> >> >> load">,
>> >> >>    InGroup<DiagGroup<"unused-volatile-lvalue">>;
>> >> >> -def ext_nodiscard_attr_is_a_cxx1z_extension : ExtWarn<
>> >> >> -  "use of the 'nodiscard' attribute is a C++1z extension">,
>> >> >> InGroup<CXX1z>;
>> >> >> +
>> >> >> +def ext_cxx14_attr : Extension<
>> >> >> +  "use of the %0 attribute is a C++14 extension">, InGroup<CXX14>;
>> >> >> +def ext_cxx1z_attr : Extension<
>> >> >> +  "use of the %0 attribute is a C++1z extension">, InGroup<CXX1z>;
>> >> >>
>> >> >>  def warn_unused_comparison : Warning<
>> >> >>    "%select{%select{|in}1equality|relational}0 comparison result
>> >> >> unused">,
>> >> >> @@ -7306,13 +7311,12 @@ def note_insert_fallthrough_fixit : Note
>> >> >>  def note_insert_break_fixit : Note<
>> >> >>    "insert 'break;' to avoid fall-through">;
>> >> >>  def err_fallthrough_attr_wrong_target : Error<
>> >> >> -  "clang::fallthrough attribute is only allowed on empty
>> statements">;
>> >> >> +  "%0 attribute is only allowed on empty statements">;
>> >> >>  def note_fallthrough_insert_semi_fixit : Note<"did you forget
>> ';'?">;
>> >> >>  def err_fallthrough_attr_outside_switch : Error<
>> >> >>    "fallthrough annotation is outside switch statement">;
>> >> >> -def warn_fallthrough_attr_invalid_placement : Warning<
>> >> >> -  "fallthrough annotation does not directly precede switch label">,
>> >> >> -  InGroup<ImplicitFallthrough>;
>> >> >> +def err_fallthrough_attr_invalid_placement : Error<
>> >> >> +  "fallthrough annotation does not directly precede switch label">;
>> >> >>  def warn_fallthrough_attr_unreachable : Warning<
>> >> >>    "fallthrough annotation in unreachable code">,
>> >> >>    InGroup<ImplicitFallthrough>;
>> >> >> @@ -7678,9 +7682,6 @@ def err_asm_naked_this_ref : Error<
>> >> >>  def err_asm_naked_parm_ref : Error<
>> >> >>    "parameter references not allowed in naked functions">;
>> >> >>
>> >> >> -def ext_deprecated_attr_is_a_cxx14_extension : ExtWarn<
>> >> >> -  "use of the 'deprecated' attribute is a C++14 extension">,
>> >> >> InGroup<CXX14>;
>> >> >> -
>> >> >>  // OpenCL warnings and errors.
>> >> >>  def err_invalid_astype_of_different_size : Error<
>> >> >>    "invalid reinterpretation: sizes of %0 and %1 must match">;
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/Sema/AttributeList.h
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/AttributeList.h?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/Sema/AttributeList.h (original)
>> >> >> +++ cfe/trunk/include/clang/Sema/AttributeList.h Mon Mar  7 18:32:55
>> >> >> 2016
>> >> >> @@ -491,6 +491,7 @@ public:
>> >> >>
>> >> >>    bool isTargetSpecificAttr() const;
>> >> >>    bool isTypeAttr() const;
>> >> >> +  bool isStmtAttr() const;
>> >> >>
>> >> >>    bool hasCustomParsing() const;
>> >> >>    unsigned getMinArgs() const;
>> >> >>
>> >> >> Modified: cfe/trunk/include/clang/Sema/ScopeInfo.h
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/ScopeInfo.h?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/include/clang/Sema/ScopeInfo.h (original)
>> >> >> +++ cfe/trunk/include/clang/Sema/ScopeInfo.h Mon Mar  7 18:32:55
>> 2016
>> >> >> @@ -107,6 +107,9 @@ public:
>> >> >>    /// \brief True if current scope is for OpenMP declare reduction
>> >> >> combiner.
>> >> >>    bool HasOMPDeclareReductionCombiner;
>> >> >>
>> >> >> +  /// \brief Whether there is a fallthrough statement in this
>> >> >> function.
>> >> >> +  bool HasFallthroughStmt : 1;
>> >> >> +
>> >> >>    /// A flag that is set when parsing a method that must call
>> super's
>> >> >>    /// implementation, such as \c -dealloc, \c -finalize, or any
>> method
>> >> >> marked
>> >> >>    /// with \c __attribute__((objc_requires_super)).
>> >> >> @@ -348,6 +351,10 @@ public:
>> >> >>      HasOMPDeclareReductionCombiner = true;
>> >> >>    }
>> >> >>
>> >> >> +  void setHasFallthroughStmt() {
>> >> >> +    HasFallthroughStmt = true;
>> >> >> +  }
>> >> >> +
>> >> >>    void setHasCXXTry(SourceLocation TryLoc) {
>> >> >>      setHasBranchProtectedScope();
>> >> >>      FirstCXXTryLoc = TryLoc;
>> >> >> @@ -371,6 +378,7 @@ public:
>> >> >>        HasIndirectGoto(false),
>> >> >>        HasDroppedStmt(false),
>> >> >>        HasOMPDeclareReductionCombiner(false),
>> >> >> +      HasFallthroughStmt(false),
>> >> >>        ObjCShouldCallSuper(false),
>> >> >>        ObjCIsDesignatedInit(false),
>> >> >>        ObjCWarnForNoDesignatedInitChain(false),
>> >> >>
>> >> >> Modified: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp (original)
>> >> >> +++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp Mon Mar  7 18:32:55
>> >> >> 2016
>> >> >> @@ -1071,6 +1071,34 @@ namespace {
>> >> >>    };
>> >> >>  } // anonymous namespace
>> >> >>
>> >> >> +static StringRef getFallthroughAttrSpelling(Preprocessor &PP,
>> >> >> +                                            SourceLocation Loc) {
>> >> >> +  TokenValue FallthroughTokens[] = {
>> >> >> +    tok::l_square, tok::l_square,
>> >> >> +    PP.getIdentifierInfo("fallthrough"),
>> >> >> +    tok::r_square, tok::r_square
>> >> >> +  };
>> >> >> +
>> >> >> +  TokenValue ClangFallthroughTokens[] = {
>> >> >> +    tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
>> >> >> +    tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
>> >> >> +    tok::r_square, tok::r_square
>> >> >> +  };
>> >> >> +
>> >> >> +  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus1z;
>> >> >> +
>> >> >> +  StringRef MacroName;
>> >> >> +  if (PreferClangAttr)
>> >> >> +    MacroName = PP.getLastMacroWithSpelling(Loc,
>> >> >> ClangFallthroughTokens);
>> >> >> +  if (MacroName.empty())
>> >> >> +    MacroName = PP.getLastMacroWithSpelling(Loc,
>> FallthroughTokens);
>> >> >> +  if (MacroName.empty() && !PreferClangAttr)
>> >> >> +    MacroName = PP.getLastMacroWithSpelling(Loc,
>> >> >> ClangFallthroughTokens);
>> >> >> +  if (MacroName.empty())
>> >> >> +    MacroName = PreferClangAttr ? "[[clang::fallthrough]]" :
>> >> >> "[[fallthrough]]";
>> >> >> +  return MacroName;
>> >> >> +}
>> >> >> +
>> >> >>  static void DiagnoseSwitchLabelsFallthrough(Sema &S,
>> >> >> AnalysisDeclContext
>> >> >> &AC,
>> >> >>                                              bool PerFunction) {
>> >> >>    // Only perform this analysis when using C++11.  There is no good
>> >> >> workflow
>> >> >> @@ -1129,15 +1157,7 @@ static void DiagnoseSwitchLabelsFallthro
>> >> >>          }
>> >> >>          if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
>> >> >>            Preprocessor &PP = S.getPreprocessor();
>> >> >> -          TokenValue Tokens[] = {
>> >> >> -            tok::l_square, tok::l_square,
>> >> >> PP.getIdentifierInfo("clang"),
>> >> >> -            tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
>> >> >> -            tok::r_square, tok::r_square
>> >> >> -          };
>> >> >> -          StringRef AnnotationSpelling = "[[clang::fallthrough]]";
>> >> >> -          StringRef MacroName = PP.getLastMacroWithSpelling(L,
>> >> >> Tokens);
>> >> >> -          if (!MacroName.empty())
>> >> >> -            AnnotationSpelling = MacroName;
>> >> >> +          StringRef AnnotationSpelling =
>> >> >> getFallthroughAttrSpelling(PP,
>> >> >> L);
>> >> >>            SmallString<64> TextToInsert(AnnotationSpelling);
>> >> >>            TextToInsert += "; ";
>> >> >>            S.Diag(L, diag::note_insert_fallthrough_fixit) <<
>> >> >> @@ -1151,7 +1171,7 @@ static void DiagnoseSwitchLabelsFallthro
>> >> >>    }
>> >> >>
>> >> >>    for (const auto *F : FM.getFallthroughStmts())
>> >> >> -    S.Diag(F->getLocStart(),
>> >> >> diag::warn_fallthrough_attr_invalid_placement);
>> >> >> +    S.Diag(F->getLocStart(),
>> >> >> diag::err_fallthrough_attr_invalid_placement);
>> >> >>  }
>> >> >>
>> >> >>  static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
>> >> >> @@ -2038,7 +2058,8 @@ AnalysisBasedWarnings::IssueWarnings(sem
>> >> >>        !Diags.isIgnored(diag::warn_unannotated_fallthrough,
>> >> >> D->getLocStart());
>> >> >>    bool FallThroughDiagPerFunction = !Diags.isIgnored(
>> >> >>        diag::warn_unannotated_fallthrough_per_function,
>> >> >> D->getLocStart());
>> >> >> -  if (FallThroughDiagFull || FallThroughDiagPerFunction) {
>> >> >> +  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
>> >> >> +      fscope->HasFallthroughStmt) {
>> >> >>      DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
>> >> >>    }
>> >> >>
>> >> >>
>> >> >> Modified: cfe/trunk/lib/Sema/AttributeList.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AttributeList.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/lib/Sema/AttributeList.cpp (original)
>> >> >> +++ cfe/trunk/lib/Sema/AttributeList.cpp Mon Mar  7 18:32:55 2016
>> >> >> @@ -159,6 +159,7 @@ struct ParsedAttrInfo {
>> >> >>    unsigned HasCustomParsing : 1;
>> >> >>    unsigned IsTargetSpecific : 1;
>> >> >>    unsigned IsType : 1;
>> >> >> +  unsigned IsStmt : 1;
>> >> >>    unsigned IsKnownToGCC : 1;
>> >> >>
>> >> >>    bool (*DiagAppertainsToDecl)(Sema &S, const AttributeList &Attr,
>> >> >> @@ -204,6 +205,10 @@ bool AttributeList::isTypeAttr() const {
>> >> >>    return getInfo(*this).IsType;
>> >> >>  }
>> >> >>
>> >> >> +bool AttributeList::isStmtAttr() const {
>> >> >> +  return getInfo(*this).IsStmt;
>> >> >> +}
>> >> >> +
>> >> >>  bool AttributeList::existsInTarget(const TargetInfo &Target) const
>> {
>> >> >>    return getInfo(*this).ExistsInTarget(Target);
>> >> >>  }
>> >> >>
>> >> >> Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
>> >> >> +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Mon Mar  7 18:32:55 2016
>> >> >> @@ -2467,7 +2467,7 @@ static void handleWarnUnusedResult(Sema
>> >> >>    // about using it as an extension.
>> >> >>    if (!S.getLangOpts().CPlusPlus1z && Attr.isCXX11Attribute() &&
>> >> >>        !Attr.getScopeName())
>> >> >> -    S.Diag(Attr.getLoc(),
>> >> >> diag::ext_nodiscard_attr_is_a_cxx1z_extension);
>> >> >> +    S.Diag(Attr.getLoc(), diag::ext_cxx1z_attr) << Attr.getName();
>> >> >>
>> >> >>    D->addAttr(::new (S.Context)
>> >> >>               WarnUnusedResultAttr(Attr.getRange(), S.Context,
>> >> >> @@ -5072,7 +5072,7 @@ static void handleDeprecatedAttr(Sema &S
>> >> >>    if (!S.getLangOpts().CPlusPlus14)
>> >> >>      if (Attr.isCXX11Attribute() &&
>> >> >>          !(Attr.hasScope() && Attr.getScopeName()->isStr("gnu")))
>> >> >> -      S.Diag(Attr.getLoc(),
>> >> >> diag::ext_deprecated_attr_is_a_cxx14_extension);
>> >> >> +      S.Diag(Attr.getLoc(), diag::ext_cxx14_attr) <<
>> Attr.getName();
>> >> >>
>> >> >>    handleAttrWithMessage<DeprecatedAttr>(S, D, Attr);
>> >> >>  }
>> >> >> @@ -5234,8 +5234,13 @@ static void ProcessDeclAttribute(Sema &S
>> >> >>
>> >> >>    switch (Attr.getKind()) {
>> >> >>    default:
>> >> >> -    // Type attributes are handled elsewhere; silently move on.
>> >> >> -    assert(Attr.isTypeAttr() && "Non-type attribute not handled");
>> >> >> +    if (!Attr.isStmtAttr()) {
>> >> >> +      // Type attributes are handled elsewhere; silently move on.
>> >> >> +      assert(Attr.isTypeAttr() && "Non-type attribute not
>> handled");
>> >> >> +      break;
>> >> >> +    }
>> >> >> +    S.Diag(Attr.getLoc(), diag::err_stmt_attribute_invalid_on_decl)
>> >> >> +        << Attr.getName() << D->getLocation();
>> >> >>      break;
>> >> >>    case AttributeList::AT_Interrupt:
>> >> >>      handleInterruptAttr(S, D, Attr);
>> >> >>
>> >> >> Modified: cfe/trunk/lib/Sema/SemaStmtAttr.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmtAttr.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/lib/Sema/SemaStmtAttr.cpp (original)
>> >> >> +++ cfe/trunk/lib/Sema/SemaStmtAttr.cpp Mon Mar  7 18:32:55 2016
>> >> >> @@ -25,9 +25,11 @@ using namespace sema;
>> >> >>
>> >> >>  static Attr *handleFallThroughAttr(Sema &S, Stmt *St, const
>> >> >> AttributeList
>> >> >> &A,
>> >> >>                                     SourceRange Range) {
>> >> >> +  FallThroughAttr Attr(A.getRange(), S.Context,
>> >> >> +                       A.getAttributeSpellingListIndex());
>> >> >>    if (!isa<NullStmt>(St)) {
>> >> >>      S.Diag(A.getRange().getBegin(),
>> >> >> diag::err_fallthrough_attr_wrong_target)
>> >> >> -        << St->getLocStart();
>> >> >> +        << Attr.getSpelling() << St->getLocStart();
>> >> >>      if (isa<SwitchCase>(St)) {
>> >> >>        SourceLocation L = S.getLocForEndOfToken(Range.getEnd());
>> >> >>        S.Diag(L, diag::note_fallthrough_insert_semi_fixit)
>> >> >> @@ -35,12 +37,20 @@ static Attr *handleFallThroughAttr(Sema
>> >> >>      }
>> >> >>      return nullptr;
>> >> >>    }
>> >> >> -  if (S.getCurFunction()->SwitchStack.empty()) {
>> >> >> +  auto *FnScope = S.getCurFunction();
>> >> >> +  if (FnScope->SwitchStack.empty()) {
>> >> >>      S.Diag(A.getRange().getBegin(),
>> >> >> diag::err_fallthrough_attr_outside_switch);
>> >> >>      return nullptr;
>> >> >>    }
>> >> >> -  return ::new (S.Context) FallThroughAttr(A.getRange(), S.Context,
>> >> >> -
>> >> >> A.getAttributeSpellingListIndex());
>> >> >> +
>> >> >> +  // If this is spelled as the standard C++1z attribute, but not in
>> >> >> C++1z, warn
>> >> >> +  // about using it as an extension.
>> >> >> +  if (!S.getLangOpts().CPlusPlus1z && A.isCXX11Attribute() &&
>> >> >> +      !A.getScopeName())
>> >> >> +    S.Diag(A.getLoc(), diag::ext_cxx1z_attr) << A.getName();
>> >> >> +
>> >> >> +  FnScope->setHasFallthroughStmt();
>> >> >> +  return ::new (S.Context) auto(Attr);
>> >> >>  }
>> >> >>
>> >> >>  static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const
>> AttributeList
>> >> >> &A,
>> >> >> @@ -266,7 +276,7 @@ static Attr *ProcessStmtAttribute(Sema &
>> >> >>    default:
>> >> >>      // if we're here, then we parsed a known attribute, but didn't
>> >> >> recognize
>> >> >>      // it as a statement attribute => it is declaration attribute
>> >> >> -    S.Diag(A.getRange().getBegin(),
>> >> >> diag::err_attribute_invalid_on_stmt)
>> >> >> +    S.Diag(A.getRange().getBegin(),
>> >> >> diag::err_decl_attribute_invalid_on_stmt)
>> >> >>          << A.getName() << St->getLocStart();
>> >> >>      return nullptr;
>> >> >>    }
>> >> >>
>> >> >> Modified: cfe/trunk/test/Analysis/cxx11-crashes.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/cxx11-crashes.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/Analysis/cxx11-crashes.cpp (original)
>> >> >> +++ cfe/trunk/test/Analysis/cxx11-crashes.cpp Mon Mar  7 18:32:55
>> 2016
>> >> >> @@ -1,5 +1,4 @@
>> >> >>  // RUN: %clang_cc1 -analyze -analyzer-checker=core -std=c++11
>> -verify
>> >> >> %s
>> >> >> -// expected-no-diagnostics
>> >> >>
>> >> >>  // radar://11485149, PR12871
>> >> >>  class PlotPoint {
>> >> >> @@ -91,6 +90,6 @@ void test() {
>> >> >>  void fallthrough() {
>> >> >>    switch (1) {
>> >> >>      case 1:
>> >> >> -      [[clang::fallthrough]];
>> >> >> +      [[clang::fallthrough]]; // expected-error {{does not directly
>> >> >> precede}}
>> >> >>    }
>> >> >>  }
>> >> >>
>> >> >> Modified: cfe/trunk/test/PCH/Inputs/cxx11-statement-attributes.h
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/PCH/Inputs/cxx11-statement-attributes.h?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/PCH/Inputs/cxx11-statement-attributes.h
>> (original)
>> >> >> +++ cfe/trunk/test/PCH/Inputs/cxx11-statement-attributes.h Mon Mar
>> 7
>> >> >> 18:32:55 2016
>> >> >> @@ -7,7 +7,8 @@ int f(int n) {
>> >> >>        [[clang::fallthrough]];  // This shouldn't generate a
>> warning.
>> >> >>      case 1:
>> >> >>        n += 20;
>> >> >> -      [[clang::fallthrough]];  // This should generate a warning:
>> >> >> "fallthrough annotation does not directly precede switch label".
>> >> >> +    case 2:  // This should generate a warning: "unannotated
>> >> >> fallthrough"
>> >> >> +      n += 35;
>> >> >>        break;
>> >> >>    }
>> >> >>    return n;
>> >> >>
>> >> >> Modified: cfe/trunk/test/PCH/cxx11-statement-attributes.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/PCH/cxx11-statement-attributes.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/PCH/cxx11-statement-attributes.cpp (original)
>> >> >> +++ cfe/trunk/test/PCH/cxx11-statement-attributes.cpp Mon Mar  7
>> >> >> 18:32:55
>> >> >> 2016
>> >> >> @@ -1,10 +1,15 @@
>> >> >>  // Sanity check.
>> >> >>  // RUN: %clang_cc1 -include %S/Inputs/cxx11-statement-attributes.h
>> >> >> -std=c++11 -Wimplicit-fallthrough -fsyntax-only %s -o - -verify
>> >> >> +// RUN: %clang_cc1 -include %S/Inputs/cxx11-statement-attributes.h
>> >> >> -std=c++1z -Wimplicit-fallthrough -fsyntax-only %s -o - -verify
>> >> >>  // Run the same tests, this time with the attributes loaded from
>> the
>> >> >> PCH
>> >> >> file.
>> >> >>  // RUN: %clang_cc1 -x c++-header -emit-pch -std=c++11 -o %t
>> >> >> %S/Inputs/cxx11-statement-attributes.h
>> >> >>  // RUN: %clang_cc1 -include-pch %t -std=c++11
>> -Wimplicit-fallthrough
>> >> >> -fsyntax-only %s -o - -verify
>> >> >> +// RUN: %clang_cc1 -x c++-header -emit-pch -std=c++1z -o %t
>> >> >> %S/Inputs/cxx11-statement-attributes.h
>> >> >> +// RUN: %clang_cc1 -include-pch %t -std=c++1z
>> -Wimplicit-fallthrough
>> >> >> -fsyntax-only %s -o - -verify
>> >> >>
>> >> >> -// expected-warning at Inputs/cxx11-statement-attributes.h:10
>> >> >> {{fallthrough
>> >> >> annotation does not directly precede switch label}}
>> >> >> +// expected-warning at Inputs/cxx11-statement-attributes.h:10
>> >> >> {{unannotated
>> >> >> fall-through}}
>> >> >> +// expected-note-re at Inputs/cxx11-statement-attributes.h:10
>> {{insert
>> >> >> '[[{{(clang::)?}}fallthrough]];'}}
>> >> >> +// expected-note at Inputs/cxx11-statement-attributes.h:10 {{insert
>> >> >> 'break;'}}
>> >> >>
>> >> >>  void g(int n) {
>> >> >>    f<1>(n);  // expected-note {{in instantiation of function
>> template
>> >> >> specialization 'f<1>' requested here}}
>> >> >>
>> >> >> Modified: cfe/trunk/test/Parser/cxx0x-attributes.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx0x-attributes.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/Parser/cxx0x-attributes.cpp (original)
>> >> >> +++ cfe/trunk/test/Parser/cxx0x-attributes.cpp Mon Mar  7 18:32:55
>> 2016
>> >> >> @@ -1,4 +1,4 @@
>> >> >> -// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only
>> -verify
>> >> >> -std=c++11 -Wc++14-compat %s
>> >> >> +// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only
>> -verify
>> >> >> -std=c++11 -Wc++14-compat -Wc++14-extensions -Wc++1z-extensions %s
>> >> >>
>> >> >>  // Need std::initializer_list
>> >> >>  namespace std {
>> >> >> @@ -347,6 +347,18 @@ deprecated
>> >> >>  ]] void bad();
>> >> >>  }
>> >> >>
>> >> >> +int fallthru(int n) {
>> >> >> +  switch (n) {
>> >> >> +  case 0:
>> >> >> +    n += 5;
>> >> >> +    [[fallthrough]]; // expected-warning {{use of the 'fallthrough'
>> >> >> attribute is a C++1z extension}}
>> >> >> +  case 1:
>> >> >> +    n *= 2;
>> >> >> +    break;
>> >> >> +  }
>> >> >> +  return n;
>> >> >> +}
>> >> >> +
>> >> >>  #define attr_name bitand
>> >> >>  #define attr_name_2(x) x
>> >> >>  #define attr_name_3(x, y) x##y
>> >> >>
>> >> >> Modified: cfe/trunk/test/SemaCXX/for-range-examples.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/for-range-examples.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/SemaCXX/for-range-examples.cpp (original)
>> >> >> +++ cfe/trunk/test/SemaCXX/for-range-examples.cpp Mon Mar  7
>> 18:32:55
>> >> >> 2016
>> >> >> @@ -226,7 +226,7 @@ namespace test7 {
>> >> >>      // we check the alignment attribute before we perform the auto
>> >> >>      // deduction.
>> >> >>      for (d alignas(1) : arr) {} // expected-error {{requires type
>> for
>> >> >> loop variable}}
>> >> >> -    for (e [[deprecated]] : arr) { e = 0; } //
>> expected-warning{{use
>> >> >> of
>> >> >> the 'deprecated' attribute is a C++14 extension}} expected-warning
>> >> >> {{deprecated}} expected-note {{here}} expected-error {{requires type
>> >> >> for
>> >> >> loop variable}}
>> >> >> +    for (e [[deprecated]] : arr) { e = 0; } // expected-warning
>> >> >> {{deprecated}} expected-note {{here}} expected-error {{requires type
>> >> >> for
>> >> >> loop variable}}
>> >> >>    }
>> >> >>  }
>> >> >>
>> >> >>
>> >> >> Modified: cfe/trunk/test/SemaCXX/generalized-deprecated.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/generalized-deprecated.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/SemaCXX/generalized-deprecated.cpp (original)
>> >> >> +++ cfe/trunk/test/SemaCXX/generalized-deprecated.cpp Mon Mar  7
>> >> >> 18:32:55
>> >> >> 2016
>> >> >> @@ -1,4 +1,4 @@
>> >> >> -// RUN: %clang_cc1 -std=c++11 -verify -fsyntax-only -fms-extensions
>> >> >> -Wno-deprecated %s
>> >> >> +// RUN: %clang_cc1 -std=c++11 -verify -fsyntax-only -fms-extensions
>> >> >> -Wno-deprecated -Wc++14-extensions %s
>> >> >>
>> >> >>  // NOTE: use -Wno-deprecated to avoid cluttering the output with
>> >> >> deprecated
>> >> >>  // warnings
>> >> >>
>> >> >> Modified: cfe/trunk/test/SemaCXX/nodiscard.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/nodiscard.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/SemaCXX/nodiscard.cpp (original)
>> >> >> +++ cfe/trunk/test/SemaCXX/nodiscard.cpp Mon Mar  7 18:32:55 2016
>> >> >> @@ -1,5 +1,5 @@
>> >> >> -// RUN: %clang_cc1 -fsyntax-only -std=c++1z -verify %s
>> >> >> -// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify -DEXT %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -std=c++1z -verify
>> -Wc++1z-extensions
>> >> >> %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify -DEXT
>> >> >> -Wc++1z-extensions %s
>> >> >>
>> >> >>  #if !defined(EXT)
>> >> >>  static_assert(__has_cpp_attribute(nodiscard) == 201603);
>> >> >>
>> >> >> Modified:
>> cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-macro.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-macro.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-macro.cpp
>> >> >> (original)
>> >> >> +++ cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-macro.cpp Mon
>> >> >> Mar
>> >> >> 7 18:32:55 2016
>> >> >> @@ -1,4 +1,8 @@
>> >> >> -// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11
>> >> >> -Wimplicit-fallthrough
>> >> >> -DCOMMAND_LINE_FALLTHROUGH=[[clang::fallthrough]] %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11
>> >> >> -Wimplicit-fallthrough -DCLANG_PREFIX
>> >> >> -DCOMMAND_LINE_FALLTHROUGH=[[clang::fallthrough]]
>> >> >> -DUNCHOSEN=[[fallthrough]]
>> >> >> %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11
>> >> >> -Wimplicit-fallthrough -DCOMMAND_LINE_FALLTHROUGH=[[fallthrough]] %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++1z
>> >> >> -Wimplicit-fallthrough -DCLANG_PREFIX
>> >> >> -DCOMMAND_LINE_FALLTHROUGH=[[clang::fallthrough]] %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++1z
>> >> >> -Wimplicit-fallthrough
>> >> >> -DCOMMAND_LINE_FALLTHROUGH=[[clang::fallthrough]] %s
>> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++1z
>> >> >> -Wimplicit-fallthrough -DCOMMAND_LINE_FALLTHROUGH=[[fallthrough]]
>> >> >> -DUNCHOSEN=[[clang::fallthrough]] %s
>> >> >>
>> >> >>  int fallthrough_compatibility_macro_from_command_line(int n) {
>> >> >>    switch (n) {
>> >> >> @@ -10,15 +14,12 @@ int fallthrough_compatibility_macro_from
>> >> >>    return n;
>> >> >>  }
>> >> >>
>> >> >> -#ifdef __clang__
>> >> >> -#if __has_feature(cxx_attributes) &&
>> >> >> __has_warning("-Wimplicit-fallthrough")
>> >> >> +#ifdef CLANG_PREFIX
>> >> >>  #define COMPATIBILITY_FALLTHROUGH   [ [ /* test */  clang /* test
>> */ \
>> >> >>      ::  fallthrough  ]  ]    // testing whitespace and comments in
>> >> >> macro
>> >> >> definition
>> >> >> -#endif
>> >> >> -#endif
>> >> >> -
>> >> >> -#ifndef COMPATIBILITY_FALLTHROUGH
>> >> >> -#define COMPATIBILITY_FALLTHROUGH do { } while (0)
>> >> >> +#else
>> >> >> +#define COMPATIBILITY_FALLTHROUGH   [ [ /* test */  /* test */ \
>> >> >> +    fallthrough  ]  ]    // testing whitespace and comments in
>> macro
>> >> >> definition
>> >> >>  #endif
>> >> >>
>> >> >>  int fallthrough_compatibility_macro_from_source(int n) {
>> >> >> @@ -32,7 +33,11 @@ int fallthrough_compatibility_macro_from
>> >> >>  }
>> >> >>
>> >> >>  // Deeper macro substitution
>> >> >> +#ifdef CLANG_PREFIX
>> >> >>  #define M1 [[clang::fallthrough]]
>> >> >> +#else
>> >> >> +#define M1 [[fallthrough]]
>> >> >> +#endif
>> >> >>  #ifdef __clang__
>> >> >>  #define M2 M1
>> >> >>  #else
>> >> >> @@ -59,12 +64,17 @@ int fallthrough_compatibility_macro_in_m
>> >> >>  #undef M2
>> >> >>  #undef COMPATIBILITY_FALLTHROUGH
>> >> >>  #undef COMMAND_LINE_FALLTHROUGH
>> >> >> +#undef UNCHOSEN
>> >> >>
>> >> >>  int fallthrough_compatibility_macro_undefined(int n) {
>> >> >>    switch (n) {
>> >> >>      case 0:
>> >> >>        n = n * 20;
>> >> >> +#if __cplusplus <= 201402L
>> >> >>      case 1: // expected-warning{{unannotated fall-through between
>> >> >> switch
>> >> >> labels}} expected-note{{insert '[[clang::fallthrough]];' to silence
>> >> >> this
>> >> >> warning}} expected-note{{insert 'break;' to avoid fall-through}}
>> >> >> +#else
>> >> >> +    case 1: // expected-warning{{unannotated fall-through between
>> >> >> switch
>> >> >> labels}} expected-note{{insert '[[fallthrough]];' to silence this
>> >> >> warning}}
>> >> >> expected-note{{insert 'break;' to avoid fall-through}}
>> >> >> +#endif
>> >> >>        ;
>> >> >>    }
>> >> >>  #define TOO_LATE [[clang::fallthrough]]
>> >> >> @@ -83,7 +93,11 @@ int fallthrough_compatibility_macro_hist
>> >> >>      case 0:
>> >> >>        n = n * 20;
>> >> >>  #undef MACRO_WITH_HISTORY
>> >> >> +#if __cplusplus <= 201402L
>> >> >>      case 1: // expected-warning{{unannotated fall-through between
>> >> >> switch
>> >> >> labels}} expected-note{{insert '[[clang::fallthrough]];' to silence
>> >> >> this
>> >> >> warning}} expected-note{{insert 'break;' to avoid fall-through}}
>> >> >> +#else
>> >> >> +    case 1: // expected-warning{{unannotated fall-through between
>> >> >> switch
>> >> >> labels}} expected-note{{insert '[[fallthrough]];' to silence this
>> >> >> warning}}
>> >> >> expected-note{{insert 'break;' to avoid fall-through}}
>> >> >> +#endif
>> >> >>        ;
>> >> >>  #define MACRO_WITH_HISTORY [[clang::fallthrough]]
>> >> >>    }
>> >> >>
>> >> >> Modified:
>> >> >> cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-per-method.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-per-method.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> ---
>> cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-per-method.cpp
>> >> >> (original)
>> >> >> +++
>> cfe/trunk/test/SemaCXX/switch-implicit-fallthrough-per-method.cpp
>> >> >> Mon
>> >> >> Mar  7 18:32:55 2016
>> >> >> @@ -41,9 +41,8 @@ int fallthrough2(int n) {
>> >> >>  void unscoped(int n) {
>> >> >>    switch (n % 2) {
>> >> >>      case 0:
>> >> >> -      // FIXME: This should be typo-corrected, probably.
>> >> >> -      [[fallthrough]]; // expected-warning{{unknown attribute
>> >> >> 'fallthrough' ignored}}
>> >> >> -    case 2: // expected-warning{{unannotated fall-through}}
>> >> >> expected-note{{clang::fallthrough}} expected-note{{break;}}
>> >> >> +      [[fallthrough]];
>> >> >> +    case 2:
>> >> >>        [[clang::fallthrough]];
>> >> >>      case 1:
>> >> >>        break;
>> >> >>
>> >> >> Modified: cfe/trunk/test/SemaCXX/switch-implicit-fallthrough.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/switch-implicit-fallthrough.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/test/SemaCXX/switch-implicit-fallthrough.cpp
>> (original)
>> >> >> +++ cfe/trunk/test/SemaCXX/switch-implicit-fallthrough.cpp Mon Mar
>> 7
>> >> >> 18:32:55 2016
>> >> >> @@ -179,18 +179,15 @@ void fallthrough_cfgblock_with_null_succ
>> >> >>
>> >> >>  int fallthrough_position(int n) {
>> >> >>    switch (n) {
>> >> >> -      [[clang::fallthrough]];  // expected-warning{{fallthrough
>> >> >> annotation does not directly precede switch label}}
>> >> >>        n += 300;
>> >> >>        [[clang::fallthrough]];  // expected-warning{{fallthrough
>> >> >> annotation in unreachable code}}
>> >> >>      case 221:
>> >> >> -      [[clang::fallthrough]];  // expected-warning{{fallthrough
>> >> >> annotation does not directly precede switch label}}
>> >> >>        return 1;
>> >> >>        [[clang::fallthrough]];  // expected-warning{{fallthrough
>> >> >> annotation in unreachable code}}
>> >> >>      case 222:
>> >> >> -      [[clang::fallthrough]];  // expected-warning{{fallthrough
>> >> >> annotation does not directly precede switch label}}
>> >> >>        n += 400;
>> >> >>      case 223:          // expected-warning{{unannotated
>> fall-through
>> >> >> between switch labels}} expected-note{{insert
>> '[[clang::fallthrough]];'
>> >> >> to
>> >> >> silence this warning}} expected-note{{insert 'break;' to avoid
>> >> >> fall-through}}
>> >> >> -      [[clang::fallthrough]]; // expected-warning{{fallthrough
>> >> >> annotation
>> >> >> does not directly precede switch label}}
>> >> >> +      ;
>> >> >>    }
>> >> >>
>> >> >>    long p = static_cast<long>(n) * n;
>> >> >> @@ -282,6 +279,23 @@ namespace PR18983 {
>> >> >>    }
>> >> >>  }
>> >> >>
>> >> >> +int fallthrough_placement_error(int n) {
>> >> >> +  switch (n) {
>> >> >> +      [[clang::fallthrough]]; // expected-warning{{fallthrough
>> >> >> annotation
>> >> >> in unreachable code}}
>> >> >> +      n += 300;
>> >> >> +    case 221:
>> >> >> +      [[clang::fallthrough]]; // expected-error{{fallthrough
>> >> >> annotation
>> >> >> does not directly precede switch label}}
>> >> >> +      return 1;
>> >> >> +    case 222:
>> >> >> +      [[clang::fallthrough]]; // expected-error{{fallthrough
>> >> >> annotation
>> >> >> does not directly precede switch label}}
>> >> >> +      n += 400;
>> >> >> +      [[clang::fallthrough]];
>> >> >> +    case 223:
>> >> >> +      [[clang::fallthrough]]; // expected-error{{fallthrough
>> >> >> annotation
>> >> >> does not directly precede switch label}}
>> >> >> +  }
>> >> >> +  return n;
>> >> >> +}
>> >> >> +
>> >> >>  int fallthrough_targets(int n) {
>> >> >>    [[clang::fallthrough]]; // expected-error{{fallthrough
>> annotation is
>> >> >> outside switch statement}}
>> >> >>
>> >> >>
>> >> >> Modified: cfe/trunk/utils/TableGen/ClangAttrEmitter.cpp
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/utils/TableGen/ClangAttrEmitter.cpp?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/utils/TableGen/ClangAttrEmitter.cpp (original)
>> >> >> +++ cfe/trunk/utils/TableGen/ClangAttrEmitter.cpp Mon Mar  7
>> 18:32:55
>> >> >> 2016
>> >> >> @@ -1761,6 +1761,7 @@ namespace {
>> >> >>
>> >> >>  static const AttrClassDescriptor AttrClassDescriptors[] = {
>> >> >>    { "ATTR", "Attr" },
>> >> >> +  { "STMT_ATTR", "StmtAttr" },
>> >> >>    { "INHERITABLE_ATTR", "InheritableAttr" },
>> >> >>    { "INHERITABLE_PARAM_ATTR", "InheritableParamAttr" },
>> >> >>    { "PARAMETER_ABI_ATTR", "ParameterABIAttr" }
>> >> >> @@ -2806,6 +2807,7 @@ void EmitClangAttrParsedAttrImpl(RecordK
>> >> >>      SS << ", " << I->second->getValueAsBit("HasCustomParsing");
>> >> >>      SS << ", " << I->second->isSubClassOf("TargetSpecificAttr");
>> >> >>      SS << ", " << I->second->isSubClassOf("TypeAttr");
>> >> >> +    SS << ", " << I->second->isSubClassOf("StmtAttr");
>> >> >>      SS << ", " << IsKnownToGCC(*I->second);
>> >> >>      SS << ", " << GenerateAppertainsTo(*I->second, OS);
>> >> >>      SS << ", " << GenerateLangOptRequirements(*I->second, OS);
>> >> >>
>> >> >> Modified: cfe/trunk/www/cxx_status.html
>> >> >> URL:
>> >> >>
>> >> >>
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=262881&r1=262880&r2=262881&view=diff
>> >> >>
>> >> >>
>> >> >>
>> ==============================================================================
>> >> >> --- cfe/trunk/www/cxx_status.html (original)
>> >> >> +++ cfe/trunk/www/cxx_status.html Mon Mar  7 18:32:55 2016
>> >> >> @@ -629,7 +629,7 @@ as the draft C++1z standard evolves.</p>
>> >> >>      <tr>
>> >> >>        <td><tt>[[fallthrough]]</tt> attribute</td>
>> >> >>        <td><a href="http://wg21.link/p0188r1">P0188R1</a></td>
>> >> >> -      <td class="none" align="center">No</td>
>> >> >> +      <td class="full" align="center">SVN</td>
>> >> >>      </tr>
>> >> >>      <tr>
>> >> >>        <td><tt>[[nodiscard]]</tt> attribute</td>
>> >> >>
>> >> >>
>> >> >> _______________________________________________
>> >> >> cfe-commits mailing list
>> >> >> cfe-commits at lists.llvm.org
>> >> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>> >> >
>> >> >
>> >
>> >
>>
>
>
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