r179662 - Add warning group -Woverloaded-shift-op-parentheses to -Wparentheses. This

Jordan Rose jordan_rose at apple.com
Wed Apr 17 11:56:40 PDT 2013


You can't apply them, but you can check the output using FileCheck -fdiagnostics-parseable-fixits. With the @LINE support in FileCheck now this isn't too bad. You can see other tests that do this, like test/FixIt/format-darwin.m.


On Apr 17, 2013, at 11:55 , Richard Trieu <rtrieu at google.com> wrote:

> How do you apply fix-its from notes?  The -fixit option only applies fix-its from errors and warnings.  Warnings like this typically have two notes with one fix-it each, one that changes the code and one to silence the warning.
> 
> 
> On Wed, Apr 17, 2013 at 9:40 AM, Jordan Rose <jordan_rose at apple.com> wrote:
> I know it's a bit of a pain, but can you add a fix-it test to make sure we get the parens in the right place? (Obviously you tested this by hand, but just in case.)
> 
> Jordan
> 
> 
> On Apr 16, 2013, at 19:12 , Richard Trieu <rtrieu at google.com> wrote:
> 
> > Author: rtrieu
> > Date: Tue Apr 16 21:12:45 2013
> > New Revision: 179662
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=179662&view=rev
> > Log:
> > Add warning group -Woverloaded-shift-op-parentheses to -Wparentheses.  This
> > will fire on code such as:
> >
> >  cout << x == 0;
> >
> > which the compiler will intrepret as
> >
> >  (cout << x) == 0;
> >
> > This warning comes with two fixits attached to notes, one for parentheses to
> > silence the warning, and another to evaluate the comparison first.
> >
> > Modified:
> >    cfe/trunk/include/clang/Basic/DiagnosticGroups.td
> >    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> >    cfe/trunk/lib/Sema/SemaExpr.cpp
> >    cfe/trunk/test/Sema/parentheses.cpp
> >
> > Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=179662&r1=179661&r2=179662&view=diff
> > ==============================================================================
> > --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
> > +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Tue Apr 16 21:12:45 2013
> > @@ -122,6 +122,7 @@ def GlobalConstructors : DiagGroup<"glob
> > def BitwiseOpParentheses: DiagGroup<"bitwise-op-parentheses">;
> > def LogicalOpParentheses: DiagGroup<"logical-op-parentheses">;
> > def ShiftOpParentheses: DiagGroup<"shift-op-parentheses">;
> > +def OverloadedShiftOpParentheses: DiagGroup<"overloaded-shift-op-parentheses">;
> > def DanglingElse: DiagGroup<"dangling-else">;
> > def DanglingField : DiagGroup<"dangling-field">;
> > def DistributedObjectModifiers : DiagGroup<"distributed-object-modifiers">;
> > @@ -352,6 +353,7 @@ def Parentheses : DiagGroup<"parentheses
> >                             [LogicalOpParentheses,
> >                              BitwiseOpParentheses,
> >                              ShiftOpParentheses,
> > +                             OverloadedShiftOpParentheses,
> >                              ParenthesesOnEquality,
> >                              DanglingElse]>;
> >
> >
> > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=179662&r1=179661&r2=179662&view=diff
> > ==============================================================================
> > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Apr 16 21:12:45 2013
> > @@ -4041,6 +4041,13 @@ def warn_bitwise_and_in_bitwise_or : War
> > def warn_logical_and_in_logical_or : Warning<
> >   "'&&' within '||'">, InGroup<LogicalOpParentheses>;
> >
> > +def warn_overloaded_shift_in_comparison :Warning<
> > +  "overloaded operator %select{>>|<<}0 has lower precedence than "
> > +  "comparison operator">,
> > +  InGroup<OverloadedShiftOpParentheses>;
> > +def note_evaluate_comparison_first :Note<
> > +  "place parentheses around comparison expression to evaluate it first">;
> > +
> > def warn_addition_in_bitshift : Warning<
> >   "operator '%0' has lower precedence than '%1'; "
> >   "'%1' will be evaluated first">, InGroup<ShiftOpParentheses>;
> >
> > Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=179662&r1=179661&r2=179662&view=diff
> > ==============================================================================
> > --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> > +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Apr 16 21:12:45 2013
> > @@ -8877,6 +8877,33 @@ static void DiagnoseAdditionInShift(Sema
> >   }
> > }
> >
> > +static void DiagnoseShiftCompare(Sema &S, SourceLocation OpLoc,
> > +                                 Expr *LHSExpr, Expr *RHSExpr) {
> > +  CXXOperatorCallExpr *OCE = dyn_cast<CXXOperatorCallExpr>(LHSExpr);
> > +  if (!OCE)
> > +    return;
> > +
> > +  FunctionDecl *FD = OCE->getDirectCallee();
> > +  if (!FD || !FD->isOverloadedOperator())
> > +    return;
> > +
> > +  OverloadedOperatorKind Kind = FD->getOverloadedOperator();
> > +  if (Kind != OO_LessLess && Kind != OO_GreaterGreater)
> > +    return;
> > +
> > +  S.Diag(OpLoc, diag::warn_overloaded_shift_in_comparison)
> > +      << LHSExpr->getSourceRange() << RHSExpr->getSourceRange()
> > +      << (Kind == OO_LessLess);
> > +  SuggestParentheses(S, OpLoc,
> > +                     S.PDiag(diag::note_evaluate_comparison_first),
> > +                     SourceRange(OCE->getArg(1)->getLocStart(),
> > +                                 RHSExpr->getLocEnd()));
> > +  SuggestParentheses(S, OCE->getOperatorLoc(),
> > +                     S.PDiag(diag::note_precedence_silence)
> > +                         << (Kind == OO_LessLess ? "<<" : ">>"),
> > +                     OCE->getSourceRange());
> > +}
> > +
> > /// DiagnoseBinOpPrecedence - Emit warnings for expressions with tricky
> > /// precedence.
> > static void DiagnoseBinOpPrecedence(Sema &Self, BinaryOperatorKind Opc,
> > @@ -8905,6 +8932,11 @@ static void DiagnoseBinOpPrecedence(Sema
> >     DiagnoseAdditionInShift(Self, OpLoc, LHSExpr, Shift);
> >     DiagnoseAdditionInShift(Self, OpLoc, RHSExpr, Shift);
> >   }
> > +
> > +  // Warn on overloaded shift operators and comparisons, such as:
> > +  // cout << 5 == 4;
> > +  if (BinaryOperator::isComparisonOp(Opc))
> > +    DiagnoseShiftCompare(Self, OpLoc, LHSExpr, RHSExpr);
> > }
> >
> > // Binary Operators.  'Tok' is the token for the operator.
> >
> > Modified: cfe/trunk/test/Sema/parentheses.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/parentheses.cpp?rev=179662&r1=179661&r2=179662&view=diff
> > ==============================================================================
> > --- cfe/trunk/test/Sema/parentheses.cpp (original)
> > +++ cfe/trunk/test/Sema/parentheses.cpp Tue Apr 16 21:12:45 2013
> > @@ -29,6 +29,12 @@ void f(Stream& s, bool b) {
> >   (void)(s << b ? "foo" : "bar"); // expected-warning {{operator '?:' has lower precedence than '<<'}} \
> >                                   // expected-note {{place parentheses around the '?:' expression to evaluate it first}} \
> >                                   // expected-note {{place parentheses around the '<<' expression to silence this warning}}
> > +  (void)(s << 5 == 1); // expected-warning {{overloaded operator << has lower precedence than comparison operator}} \
> > +                       // expected-note {{place parentheses around the '<<' expression to silence this warning}} \
> > +                       // expected-note {{place parentheses around comparison expression to evaluate it first}}
> > +  (void)(s >> 5 == 1); // expected-warning {{overloaded operator >> has lower precedence than comparison operator}} \
> > +                       // expected-note {{place parentheses around the '>>' expression to silence this warning}} \
> > +                       // expected-note {{place parentheses around comparison expression to evaluate it first}}
> > }
> >
> > struct S {
> >
> >
> > _______________________________________________
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> > cfe-commits at cs.uiuc.edu
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> 
> 

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