r256595 - Emit a -Wmicrosoft warning when pasting /##/ into a comment token in MS mode.

Nico Weber via cfe-commits cfe-commits at lists.llvm.org
Tue Dec 29 15:35:39 PST 2015


On Tue, Dec 29, 2015 at 6:28 PM, Richard Smith <richard at metafoo.co.uk>
wrote:

> On Tue, Dec 29, 2015 at 3:23 PM, Nico Weber <thakis at chromium.org> wrote:
>
>> On Tue, Dec 29, 2015 at 6:16 PM, Richard Smith via cfe-commits <
>> cfe-commits at lists.llvm.org> wrote:
>>
>>> On Tue, Dec 29, 2015 at 3:06 PM, Nico Weber via cfe-commits <
>>> cfe-commits at lists.llvm.org> wrote:
>>>
>>>> Author: nico
>>>> Date: Tue Dec 29 17:06:17 2015
>>>> New Revision: 256595
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=256595&view=rev
>>>> Log:
>>>> Emit a -Wmicrosoft warning when pasting /##/ into a comment token in MS
>>>> mode.
>>>>
>>>> Modified:
>>>>     cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>>>     cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td
>>>>     cfe/trunk/include/clang/Lex/TokenLexer.h
>>>>     cfe/trunk/lib/Lex/PPLexerChange.cpp
>>>>     cfe/trunk/lib/Lex/TokenLexer.cpp
>>>>     cfe/trunk/test/Preprocessor/macro_paste_msextensions.c
>>>>
>>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
>>>> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Tue Dec 29
>>>> 17:06:17 2015
>>>> @@ -765,6 +765,7 @@ def MicrosoftCast : DiagGroup<"microsoft
>>>>  def MicrosoftConstInit : DiagGroup<"microsoft-const-init">;
>>>>  def MicrosoftVoidPseudoDtor : DiagGroup<"microsoft-void-pseudo-dtor">;
>>>>  def MicrosoftAnonTag : DiagGroup<"microsoft-anon-tag">;
>>>> +def MicrosoftCommentPaste : DiagGroup<"microsoft-comment-paste">;
>>>>  // Aliases.
>>>>  def : DiagGroup<"msvc-include", [MicrosoftInclude]>;
>>>>                  // -Wmsvc-include = -Wmicrosoft-include
>>>> @@ -778,7 +779,8 @@ def Microsoft : DiagGroup<"microsoft",
>>>>       MicrosoftEnumValue, MicrosoftDefaultArgRedefinition,
>>>> MicrosoftTemplate,
>>>>       MicrosoftRedeclareStatic, MicrosoftEnumForwardReference,
>>>> MicrosoftGoto,
>>>>       MicrosoftFlexibleArray, MicrosoftExtraQualification,
>>>> MicrosoftCast,
>>>> -     MicrosoftConstInit, MicrosoftVoidPseudoDtor, MicrosoftAnonTag]>;
>>>> +     MicrosoftConstInit, MicrosoftVoidPseudoDtor, MicrosoftAnonTag,
>>>> +     MicrosoftCommentPaste]>;
>>>>
>>>>  def ObjCNonUnifiedException : DiagGroup<"objc-nonunified-exceptions">;
>>>>
>>>>
>>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td (original)
>>>> +++ cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td Tue Dec 29
>>>> 17:06:17 2015
>>>> @@ -59,6 +59,9 @@ def ext_dollar_in_identifier : Extension
>>>>  def ext_charize_microsoft : Extension<
>>>>    "charizing operator #@ is a Microsoft extension">,
>>>>    InGroup<MicrosoftCharize>;
>>>> +def ext_comment_paste_microsoft : Extension<
>>>> +  "pasting two '/' tokens into a '//' comment token is a Microsoft
>>>> extension">,
>>>>
>>>
>>> It's not really technically correct to call this a token. Maybe drop the
>>> word "token" here?
>>>
>>
>> Thanks for the review! You mean only the second "token", not the first
>> "tokens", right?
>>
>
> Yes.
>

Done in 256600.


>
> And FWIW I find this extension horrifying. =)
>
> +  InGroup<MicrosoftCommentPaste>;
>>>>
>>>>  def ext_token_used : Extension<"extension used">,
>>>>    InGroup<DiagGroup<"language-extension-token">>;
>>>>
>>>> Modified: cfe/trunk/include/clang/Lex/TokenLexer.h
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Lex/TokenLexer.h?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/include/clang/Lex/TokenLexer.h (original)
>>>> +++ cfe/trunk/include/clang/Lex/TokenLexer.h Tue Dec 29 17:06:17 2015
>>>> @@ -175,7 +175,7 @@ private:
>>>>    /// macro, other active macros, and anything left on the current
>>>> physical
>>>>    /// source line of the expanded buffer.  Handle this by returning the
>>>>    /// first token on the next line.
>>>> -  void HandleMicrosoftCommentPaste(Token &Tok);
>>>> +  void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc);
>>>>
>>>>    /// \brief If \p loc is a FileID and points inside the current macro
>>>>    /// definition, returns the appropriate source location pointing at
>>>> the
>>>>
>>>> Modified: cfe/trunk/lib/Lex/PPLexerChange.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPLexerChange.cpp?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Lex/PPLexerChange.cpp (original)
>>>> +++ cfe/trunk/lib/Lex/PPLexerChange.cpp Tue Dec 29 17:06:17 2015
>>>> @@ -561,7 +561,6 @@ void Preprocessor::RemoveTopOfLexerStack
>>>>  void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) {
>>>>    assert(CurTokenLexer && !CurPPLexer &&
>>>>           "Pasted comment can only be formed from macro");
>>>> -
>>>>    // We handle this by scanning for the closest real lexer, switching
>>>> it to
>>>>    // raw mode and preprocessor mode.  This will cause it to return \n
>>>> as an
>>>>    // explicit EOD token.
>>>>
>>>> Modified: cfe/trunk/lib/Lex/TokenLexer.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/TokenLexer.cpp?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Lex/TokenLexer.cpp (original)
>>>> +++ cfe/trunk/lib/Lex/TokenLexer.cpp Tue Dec 29 17:06:17 2015
>>>> @@ -624,21 +624,22 @@ bool TokenLexer::PasteTokens(Token &Tok)
>>>>        // error.  This occurs with "x ## +"  and other stuff.  Return
>>>> with Tok
>>>>        // unmodified and with RHS as the next token to lex.
>>>>        if (isInvalid) {
>>>> +        // Explicitly convert the token location to have proper
>>>> expansion
>>>> +        // information so that the user knows where it came from.
>>>> +        SourceManager &SM = PP.getSourceManager();
>>>> +        SourceLocation Loc =
>>>> +          SM.createExpansionLoc(PasteOpLoc, ExpandLocStart,
>>>> ExpandLocEnd, 2);
>>>> +
>>>>          // Test for the Microsoft extension of /##/ turning into //
>>>> here on the
>>>>          // error path.
>>>>          if (PP.getLangOpts().MicrosoftExt && Tok.is(tok::slash) &&
>>>>              RHS.is(tok::slash)) {
>>>> -          HandleMicrosoftCommentPaste(Tok);
>>>> +          HandleMicrosoftCommentPaste(Tok, Loc);
>>>>            return true;
>>>>          }
>>>>
>>>>          // Do not emit the error when preprocessing assembler code.
>>>>          if (!PP.getLangOpts().AsmPreprocessor) {
>>>> -          // Explicitly convert the token location to have proper
>>>> expansion
>>>> -          // information so that the user knows where it came from.
>>>> -          SourceManager &SM = PP.getSourceManager();
>>>> -          SourceLocation Loc =
>>>> -            SM.createExpansionLoc(PasteOpLoc, ExpandLocStart,
>>>> ExpandLocEnd, 2);
>>>>            // If we're in microsoft extensions mode, downgrade this
>>>> from a hard
>>>>            // error to an extension that defaults to an error.  This
>>>> allows
>>>>            // disabling it.
>>>> @@ -719,7 +720,9 @@ bool TokenLexer::isParsingPreprocessorDi
>>>>  /// macro, other active macros, and anything left on the current
>>>> physical
>>>>  /// source line of the expanded buffer.  Handle this by returning the
>>>>  /// first token on the next line.
>>>> -void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok) {
>>>> +void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok,
>>>> SourceLocation OpLoc) {
>>>> +  PP.Diag(OpLoc, diag::ext_comment_paste_microsoft);
>>>> +
>>>>    // We 'comment out' the rest of this macro by just ignoring the rest
>>>> of the
>>>>    // tokens that have not been lexed yet, if any.
>>>>
>>>>
>>>> Modified: cfe/trunk/test/Preprocessor/macro_paste_msextensions.c
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Preprocessor/macro_paste_msextensions.c?rev=256595&r1=256594&r2=256595&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/Preprocessor/macro_paste_msextensions.c (original)
>>>> +++ cfe/trunk/test/Preprocessor/macro_paste_msextensions.c Tue Dec 29
>>>> 17:06:17 2015
>>>> @@ -1,3 +1,4 @@
>>>> +// RUN: %clang_cc1 -verify -fms-extensions -Wmicrosoft %s
>>>>  // RUN: not %clang_cc1 -P -E -fms-extensions %s | FileCheck
>>>> -strict-whitespace %s
>>>>
>>>>  // This horrible stuff should preprocess into (other than whitespace):
>>>> @@ -10,6 +11,7 @@ int foo;
>>>>  // CHECK: int foo;
>>>>
>>>>  #define comment /##/  dead tokens live here
>>>> +// expected-warning at +1 {{pasting two '/' tokens}}
>>>>  comment This is stupidity
>>>>
>>>>  int bar;
>>>> @@ -18,6 +20,7 @@ int bar;
>>>>
>>>>  #define nested(x) int x comment cute little dead tokens...
>>>>
>>>> +// expected-warning at +1 {{pasting two '/' tokens}}
>>>>  nested(baz)  rise of the dead tokens
>>>>
>>>>  ;
>>>> @@ -29,13 +32,13 @@ nested(baz)  rise of the dead tokens
>>>>  // rdar://8197149 - VC++ allows invalid token pastes: (##baz
>>>>  #define foo(x) abc(x)
>>>>  #define bar(y) foo(##baz(y))
>>>> -bar(q)
>>>> +bar(q) // expected-warning {{type specifier missing}} expected-error
>>>> {{invalid preprocessing token}} expected-error {{parameter list without
>>>> types}}
>>>>
>>>>  // CHECK: abc(baz(q))
>>>>
>>>>
>>>>  #define str(x) #x
>>>>  #define collapse_spaces(a, b, c, d) str(a ## - ## b ## - ## c ## d)
>>>> -collapse_spaces(1a, b2, 3c, d4)
>>>> +collapse_spaces(1a, b2, 3c, d4) // expected-error 4 {{invalid
>>>> preprocessing token}} expected-error {{expected function body}}
>>>>
>>>>  // CHECK: "1a-b2-3cd4"
>>>>
>>>>
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>>>
>>>
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