[cfe-commits] r170399 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaDecl.cpp test/Sema/warn-missing-prototypes.c

[Douglas Gregor]

On Dec 17, 2012, at 5:58 PM, Jordan Rose <jordan_rose at apple.com> wrote:

> I convinced myself it should never happen, but can you add a negative C++ test as well?
> 
> (In C++ an empty parameter list is equivalent to one with 'void', but that would make the advance declaration a prototype.)

I don't see the point. C++ doesn't have functions without prototypes.

	- Doug

> Jordan
> 
> 
> On Dec 17, 2012, at 17:29 , Anders Carlsson <andersca at mac.com> wrote:
> 
>> Author: andersca
>> Date: Mon Dec 17 19:29:20 2012
>> New Revision: 170399
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=170399&view=rev
>> Log:
>> When warning about a missing prototype because a function declaration is missing 'void', insert a fixit to add the void.
>> 
>> Modified:
>>   cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>   cfe/trunk/lib/Sema/SemaDecl.cpp
>>   cfe/trunk/test/Sema/warn-missing-prototypes.c
>> 
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=170399&r1=170398&r2=170399&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Dec 17 19:29:20 2012
>> @@ -3176,6 +3176,8 @@
>> def warn_missing_prototype : Warning<
>>  "no previous prototype for function %0">,
>>  InGroup<DiagGroup<"missing-prototypes">>, DefaultIgnore;
>> +def note_declaration_not_a_prototype : Note<
>> +  "this declaration is not a prototype; add 'void' to make it a prototype for a zero-parameter function">; 
>> def warn_missing_variable_declarations : Warning<
>>  "no previous extern declaration for non-static variable %0">,
>>  InGroup<DiagGroup<"missing-variable-declarations">>, DefaultIgnore;
>> 
>> Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=170399&r1=170398&r2=170399&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon Dec 17 19:29:20 2012
>> @@ -7762,7 +7762,8 @@
>>  return ActOnStartOfFunctionDef(FnBodyScope, DP);
>> }
>> 
>> -static bool ShouldWarnAboutMissingPrototype(const FunctionDecl *FD) {
>> +static bool ShouldWarnAboutMissingPrototype(const FunctionDecl *FD, 
>> +                             const FunctionDecl*& PossibleZeroParamPrototype) {
>>  // Don't warn about invalid declarations.
>>  if (FD->isInvalidDecl())
>>    return false;
>> @@ -7804,6 +7805,8 @@
>>      continue;
>> 
>>    MissingPrototype = !Prev->getType()->isFunctionProtoType();
>> +    if (FD->getNumParams() == 0)
>> +      PossibleZeroParamPrototype = Prev;
>>    break;
>>  }
>> 
>> @@ -7869,8 +7872,22 @@
>>  //   prototype declaration. This warning is issued even if the
>>  //   definition itself provides a prototype. The aim is to detect
>>  //   global functions that fail to be declared in header files.
>> -  if (ShouldWarnAboutMissingPrototype(FD))
>> +  const FunctionDecl *PossibleZeroParamPrototype = 0;
>> +  if (ShouldWarnAboutMissingPrototype(FD, PossibleZeroParamPrototype)) {
>>    Diag(FD->getLocation(), diag::warn_missing_prototype) << FD;
>> +  
>> +    if (PossibleZeroParamPrototype) {
>> +      // We found a declaration that is not a prototype, 
>> +      // but that could be a zero-parameter prototype
>> +      TypeSourceInfo* TI = PossibleZeroParamPrototype->getTypeSourceInfo();
>> +      TypeLoc TL = TI->getTypeLoc();
>> +      if (FunctionNoProtoTypeLoc* FTL = dyn_cast<FunctionNoProtoTypeLoc>(&TL))
>> +        Diag(PossibleZeroParamPrototype->getLocation(), 
>> +             diag::note_declaration_not_a_prototype)
>> +          << PossibleZeroParamPrototype 
>> +          << FixItHint::CreateInsertion(FTL->getRParenLoc(), "void");
>> +    }
>> +  }
>> 
>>  if (FnBodyScope)
>>    PushDeclContext(FnBodyScope, FD);
>> 
>> Modified: cfe/trunk/test/Sema/warn-missing-prototypes.c
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-missing-prototypes.c?rev=170399&r1=170398&r2=170399&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/Sema/warn-missing-prototypes.c (original)
>> +++ cfe/trunk/test/Sema/warn-missing-prototypes.c Mon Dec 17 19:29:20 2012
>> @@ -1,4 +1,5 @@
>> -// RUN: %clang -Wmissing-prototypes -fsyntax-only -Xclang -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -Wdocumentation -Wmissing-prototypes -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -Wdocumentation -Wmissing-prototypes -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
>> 
>> int f();
>> 
>> @@ -35,3 +36,8 @@
>> 
>> // rdar://6759522
>> int main(void) { return 0; }
>> +
>> +void not_a_prototype_test(); // expected-note{{this declaration is not a prototype; add 'void' to make it a prototype for a zero-parameter function}}
>> +void not_a_prototype_test() { } // expected-warning{{no previous prototype for function 'not_a_prototype_test'}}
>> +
>> +// CHECK: fix-it:"{{.*}}":{40:27-40:27}:"void"
>> 
>> 
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