r212957 - Improve error recovery around colon.

Reid Kleckner rnk at google.com
Mon Jul 14 11:28:45 PDT 2014


This broke the self-host on llvm/lib/Option/ArgList.cpp, so I reverted it
in r212965.


On Mon, Jul 14, 2014 at 9:42 AM, Serge Pavlov <sepavloff at gmail.com> wrote:

> Author: sepavloff
> Date: Mon Jul 14 11:42:20 2014
> New Revision: 212957
>
> URL: http://llvm.org/viewvc/llvm-project?rev=212957&view=rev
> Log:
> Improve error recovery around colon.
>
> Recognize additional cases, when '::' is mistyped as ':'.
> This is a fix to RP18587 - colons have too much protection in
> member-declarations.
>
> Differential Revision: http://reviews.llvm.org/D3653
>
> Modified:
>     cfe/trunk/lib/Parse/ParseDecl.cpp
>     cfe/trunk/lib/Parse/ParseDeclCXX.cpp
>     cfe/trunk/test/SemaCXX/enum-bitfield.cpp
>     cfe/trunk/test/SemaCXX/nested-name-spec.cpp
>
> Modified: cfe/trunk/lib/Parse/ParseDecl.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDecl.cpp?rev=212957&r1=212956&r2=212957&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Parse/ParseDecl.cpp (original)
> +++ cfe/trunk/lib/Parse/ParseDecl.cpp Mon Jul 14 11:42:20 2014
> @@ -2715,24 +2715,23 @@ void Parser::ParseDeclarationSpecifiers(
>        // typedef-name
>      case tok::kw_decltype:
>      case tok::identifier: {
> +      // This identifier can only be a typedef name if we haven't already
> seen
> +      // a type-specifier.  Without this check we misparse:
> +      //  typedef int X; struct Y { short X; };  as 'short int'.
> +      if (DS.hasTypeSpecifier())
> +        goto DoneWithDeclSpec;
> +
>        // In C++, check to see if this is a scope specifier like
> foo::bar::, if
>        // so handle it as such.  This is important for ctor parsing.
>        if (getLangOpts().CPlusPlus) {
>          if (TryAnnotateCXXScopeToken(EnteringContext)) {
> -          if (!DS.hasTypeSpecifier())
> -            DS.SetTypeSpecError();
> +          DS.SetTypeSpecError();
>            goto DoneWithDeclSpec;
>          }
>          if (!Tok.is(tok::identifier))
>            continue;
>        }
>
> -      // This identifier can only be a typedef name if we haven't already
> seen
> -      // a type-specifier.  Without this check we misparse:
> -      //  typedef int X; struct Y { short X; };  as 'short int'.
> -      if (DS.hasTypeSpecifier())
> -        goto DoneWithDeclSpec;
> -
>        // Check for need to substitute AltiVec keyword tokens.
>        if (TryAltiVecToken(DS, Loc, PrevSpec, DiagID, isInvalid))
>          break;
> @@ -4529,7 +4528,9 @@ void Parser::ParseDeclaratorInternal(Dec
>    // Member pointers get special handling, since there's no place for the
>    // scope spec in the generic path below.
>    if (getLangOpts().CPlusPlus &&
> -      (Tok.is(tok::coloncolon) || Tok.is(tok::identifier) ||
> +      (Tok.is(tok::coloncolon) ||
> +       (Tok.is(tok::identifier) &&
> +        (NextToken().is(tok::coloncolon) || NextToken().is(tok::less))) ||
>         Tok.is(tok::annot_cxxscope))) {
>      bool EnteringContext = D.getContext() == Declarator::FileContext ||
>                             D.getContext() == Declarator::MemberContext;
> @@ -4722,6 +4723,11 @@ void Parser::ParseDirectDeclarator(Decla
>    DeclaratorScopeObj DeclScopeObj(*this, D.getCXXScopeSpec());
>
>    if (getLangOpts().CPlusPlus && D.mayHaveIdentifier()) {
> +    // Don't parse FOO:BAR as if it were a typo for FOO::BAR inside a
> class, in
> +    // this context it is a bitfield.
> +    ColonProtectionRAIIObject X(*this,
> +                                D.getContext() ==
> Declarator::MemberContext);
> +
>      // ParseDeclaratorInternal might already have parsed the scope.
>      if (D.getCXXScopeSpec().isEmpty()) {
>        bool EnteringContext = D.getContext() == Declarator::FileContext ||
>
> Modified: cfe/trunk/lib/Parse/ParseDeclCXX.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDeclCXX.cpp?rev=212957&r1=212956&r2=212957&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Parse/ParseDeclCXX.cpp (original)
> +++ cfe/trunk/lib/Parse/ParseDeclCXX.cpp Mon Jul 14 11:42:20 2014
> @@ -1239,7 +1239,8 @@ void Parser::ParseClassSpecifier(tok::To
>    // Parse the (optional) nested-name-specifier.
>    CXXScopeSpec &SS = DS.getTypeSpecScope();
>    if (getLangOpts().CPlusPlus) {
> -    // "FOO : BAR" is not a potential typo for "FOO::BAR".
> +    // "FOO : BAR" is not a potential typo for "FOO::BAR".  In this
> context it
> +    // is a base-specifier-list.
>      ColonProtectionRAIIObject X(*this);
>
>      if (ParseOptionalCXXScopeSpecifier(SS, ParsedType(), EnteringContext))
> @@ -1926,14 +1927,8 @@ void Parser::ParseCXXMemberDeclaratorBef
>    //   declarator pure-specifier[opt]
>    //   declarator brace-or-equal-initializer[opt]
>    //   identifier[opt] ':' constant-expression
> -  if (Tok.isNot(tok::colon)) {
> -    // Don't parse FOO:BAR as if it were a typo for FOO::BAR, in this
> context it
> -    // is a bitfield.
> -    // FIXME: This should only apply when parsing the id-expression (see
> -    // PR18587).
> -    ColonProtectionRAIIObject X(*this);
> +  if (Tok.isNot(tok::colon))
>      ParseDeclarator(DeclaratorInfo);
> -  }
>
>    if (!DeclaratorInfo.isFunctionDeclarator() &&
> TryConsumeToken(tok::colon)) {
>      BitfieldSize = ParseConstantExpression();
> @@ -2015,6 +2010,14 @@ void Parser::ParseCXXClassMemberDeclarat
>      return;
>    }
>
> +  // Turn on colon protection early, while parsing declspec, although
> there is
> +  // nothing to protect there. It prevents from false errors if error
> recovery
> +  // incorrectly determines where the declspec ends, as in the example:
> +  //   struct A { enum class B { C }; };
> +  //   const int C = 4;
> +  //   struct D { A::B : C; };
> +  ColonProtectionRAIIObject X(*this);
> +
>    // Access declarations.
>    bool MalformedTypeSpec = false;
>    if (!TemplateInfo.Kind &&
> @@ -2128,13 +2131,11 @@ void Parser::ParseCXXClassMemberDeclarat
>    if (MalformedTypeSpec)
>      DS.SetTypeSpecError();
>
> -  {
> -    // Don't parse FOO:BAR as if it were a typo for FOO::BAR, in this
> context it
> -    // is a bitfield.
> -    ColonProtectionRAIIObject X(*this);
> -    ParseDeclarationSpecifiers(DS, TemplateInfo, AS, DSC_class,
> -                               &CommonLateParsedAttrs);
> -  }
> +  ParseDeclarationSpecifiers(DS, TemplateInfo, AS, DSC_class,
> +                             &CommonLateParsedAttrs);
> +
> +  // Turn off colon protection that was set for declspec.
> +  X.restore();
>
>    // If we had a free-standing type definition with a missing semicolon,
> we
>    // may get this far before the problem becomes obvious.
>
> Modified: cfe/trunk/test/SemaCXX/enum-bitfield.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/enum-bitfield.cpp?rev=212957&r1=212956&r2=212957&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/enum-bitfield.cpp (original)
> +++ cfe/trunk/test/SemaCXX/enum-bitfield.cpp Mon Jul 14 11:42:20 2014
> @@ -16,3 +16,15 @@ struct Y {
>    enum E : int(2);
>    enum E : Z(); // expected-error{{integral constant expression must have
> integral or unscoped enumeration type, not 'Z'}}
>  };
> +
> +namespace pr18587 {
> +struct A {
> +  enum class B {
> +    C
> +  };
> +};
> +const int C = 4;
> +struct D {
> +  A::B : C;
> +};
> +}
>
> Modified: cfe/trunk/test/SemaCXX/nested-name-spec.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/nested-name-spec.cpp?rev=212957&r1=212956&r2=212957&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/nested-name-spec.cpp (original)
> +++ cfe/trunk/test/SemaCXX/nested-name-spec.cpp Mon Jul 14 11:42:20 2014
> @@ -311,3 +311,102 @@ namespace N {
>
>  namespace TypedefNamespace { typedef int F; };
>  TypedefNamespace::F::NonexistentName BadNNSWithCXXScopeSpec; //
> expected-error {{'F' (aka 'int') is not a class, namespace, or scoped
> enumeration}}
> +
> +namespace PR18587 {
> +
> +struct C1 {
> +  int a, b, c;
> +  typedef int C2;
> +  struct B1 {
> +    struct B2 {
> +      int a, b, c;
> +    };
> +  };
> +};
> +struct C2 { static const unsigned N1 = 1; };
> +struct B1 {
> +  enum E1 { B2 = 2 };
> +  static const int B3 = 3;
> +};
> +const int N1 = 2;
> +
> +// Function declarators
> +struct S1a { int f(C1::C2); };
> +struct S1b { int f(C1:C2); };  // expected-error{{unexpected ':' in
> nested name specifier; did you mean '::'?}}
> +
> +struct S2a {
> +  C1::C2 f(C1::C2);
> +};
> +struct S2c {
> +  C1::C2 f(C1:C2);  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +};
> +
> +struct S3a {
> +  int f(C1::C2), C2 : N1;
> +  int g : B1::B2;
> +};
> +struct S3b {
> +  int g : B1:B2;  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +};
> +
> +// Inside square brackets
> +struct S4a {
> +  int f[C2::N1];
> +};
> +struct S4b {
> +  int f[C2:N1];  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +};
> +
> +struct S5a {
> +  int f(int xx[B1::B3 ? C2::N1 : B1::B2]);
> +};
> +struct S5b {
> +  int f(int xx[B1::B3 ? C2::N1 : B1:B2]);  // expected-error{{unexpected
> ':' in nested name specifier; did you mean '::'?}}
> +};
> +struct S5c {
> +  int f(int xx[B1:B3 ? C2::N1 : B1::B2]);  // expected-error{{unexpected
> ':' in nested name specifier; did you mean '::'?}}
> +};
> +
> +// Bit fields
> +struct S6a {
> +  C1::C2 m1 : B1::B2;
> +};
> +struct S6c {
> +  C1::C2 m1 : B1:B2;  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +};
> +struct S6d {
> +  int C2:N1;
> +};
> +struct S6e {
> +  static const int N = 3;
> +  B1::E1 : N;
> +};
> +struct S6g {
> +  C1::C2 : B1:B2;  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +  B1::E1 : B1:B2;  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +};
> +
> +// Template parameters
> +template <int N> struct T1 {
> +  int a,b,c;
> +  static const unsigned N1 = N;
> +  typedef unsigned C1;
> +};
> +T1<C2::N1> var_1a;
> +T1<C2:N1> var_1b;  // expected-error{{unexpected ':' in nested name
> specifier; did you mean '::'?}}
> +template<int N> int F() {}
> +int (*X1)() = (B1::B2 ? F<1> : F<2>);
> +int (*X2)() = (B1:B2 ? F<1> : F<2>);  // expected-error{{unexpected ':'
> in nested name specifier; did you mean '::'?}}
> +
> +// Bit fields + templates
> +struct S7a {
> +  T1<B1::B2>::C1 m1 : T1<B1::B2>::N1;
> +};
> +struct S7b {
> +  T1<B1:B2>::C1 m1 : T1<B1::B2>::N1;  // expected-error{{unexpected ':'
> in nested name specifier; did you mean '::'?}}
> +};
> +struct S7c {
> +  T1<B1::B2>::C1 m1 : T1<B1:B2>::N1;  // expected-error{{unexpected ':'
> in nested name specifier; did you mean '::'?}}
> +};
> +
> +}
>
>
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