[cfe-commits] r125995 - in /cfe/trunk: include/clang/AST/Expr.h include/clang/Basic/DiagnosticSemaKinds.td include/clang/Sema/Sema.h lib/AST/Expr.cpp lib/Sema/SemaExpr.cpp lib/Sema/SemaExprCXX.cpp test/Sema/conditional-expr.c test/SemaCXX/__null.cpp test/SemaCXX/conditional-expr.cpp test/SemaCXX/nullptr.cpp
Chandler Carruth
chandlerc at gmail.com
Fri Feb 18 15:54:50 PST 2011
Author: chandlerc
Date: Fri Feb 18 17:54:50 2011
New Revision: 125995
URL: http://llvm.org/viewvc/llvm-project?rev=125995&view=rev
Log:
Initial steps to improve diagnostics when there is a NULL and
a non-pointer on the two sides of a conditional expression.
Patch by Stephen Hines and Mihai Rusu.
Modified:
cfe/trunk/include/clang/AST/Expr.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/AST/Expr.cpp
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/lib/Sema/SemaExprCXX.cpp
cfe/trunk/test/Sema/conditional-expr.c
cfe/trunk/test/SemaCXX/__null.cpp
cfe/trunk/test/SemaCXX/conditional-expr.cpp
cfe/trunk/test/SemaCXX/nullptr.cpp
Modified: cfe/trunk/include/clang/AST/Expr.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Expr.h?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Expr.h (original)
+++ cfe/trunk/include/clang/AST/Expr.h Fri Feb 18 17:54:50 2011
@@ -437,6 +437,22 @@
/// EvaluateAsLValue - Evaluate an expression to see if it's a lvalue.
bool EvaluateAsAnyLValue(EvalResult &Result, const ASTContext &Ctx) const;
+ /// \brief Enumeration used to describe the kind of Null pointer constant
+ /// returned from \c isNullPointerConstant().
+ enum NullPointerConstantKind {
+ /// \brief Expression is not a Null pointer constant.
+ NPCK_NotNull = 0,
+
+ /// \brief Expression is a Null pointer constant built from a zero integer.
+ NPCK_ZeroInteger,
+
+ /// \brief Expression is a C++0X nullptr.
+ NPCK_CXX0X_nullptr,
+
+ /// \brief Expression is a GNU-style __null constant.
+ NPCK_GNUNull
+ };
+
/// \brief Enumeration used to describe how \c isNullPointerConstant()
/// should cope with value-dependent expressions.
enum NullPointerConstantValueDependence {
@@ -452,11 +468,12 @@
NPC_ValueDependentIsNotNull
};
- /// isNullPointerConstant - C99 6.3.2.3p3 - Return true if this is either an
- /// integer constant expression with the value zero, or if this is one that is
- /// cast to void*.
- bool isNullPointerConstant(ASTContext &Ctx,
- NullPointerConstantValueDependence NPC) const;
+ /// isNullPointerConstant - C99 6.3.2.3p3 - Test if this reduces down to
+ /// a Null pointer constant. The return value can further distinguish the
+ /// kind of NULL pointer constant that was detected.
+ NullPointerConstantKind isNullPointerConstant(
+ ASTContext &Ctx,
+ NullPointerConstantValueDependence NPC) const;
/// isOBJCGCCandidate - Return true if this expression may be used in a read/
/// write barrier.
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Feb 18 17:54:50 2011
@@ -3147,6 +3147,8 @@
"incomplete type %0 used in type trait expression">;
def err_expected_ident_or_lparen : Error<"expected identifier or '('">;
+def err_typecheck_cond_incompatible_operands_null : Error<
+ "non-pointer operand type %0 incompatible with %select{NULL|nullptr}1">;
} // End of general sema category.
// inline asm.
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Fri Feb 18 17:54:50 2011
@@ -4774,6 +4774,9 @@
QualType FindCompositeObjCPointerType(Expr *&LHS, Expr *&RHS,
SourceLocation questionLoc);
+ bool DiagnoseConditionalForNull(Expr *LHS, Expr *RHS,
+ SourceLocation QuestionLoc);
+
/// type checking for vector binary operators.
QualType CheckVectorOperands(SourceLocation l, Expr *&lex, Expr *&rex);
QualType CheckVectorCompareOperands(Expr *&lex, Expr *&rx,
Modified: cfe/trunk/lib/AST/Expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Expr.cpp (original)
+++ cfe/trunk/lib/AST/Expr.cpp Fri Feb 18 17:54:50 2011
@@ -2132,11 +2132,14 @@
return isEvaluatable(Ctx);
}
-/// isNullPointerConstant - C99 6.3.2.3p3 - Return true if this is either an
-/// integer constant expression with the value zero, or if this is one that is
-/// cast to void*.
-bool Expr::isNullPointerConstant(ASTContext &Ctx,
- NullPointerConstantValueDependence NPC) const {
+/// isNullPointerConstant - C99 6.3.2.3p3 - Return whether this is a null
+/// pointer constant or not, as well as the specific kind of constant detected.
+/// Null pointer constants can be integer constant expressions with the
+/// value zero, casts of zero to void*, nullptr (C++0X), or __null
+/// (a GNU extension).
+Expr::NullPointerConstantKind
+Expr::isNullPointerConstant(ASTContext &Ctx,
+ NullPointerConstantValueDependence NPC) const {
if (isValueDependent()) {
switch (NPC) {
case NPC_NeverValueDependent:
@@ -2144,10 +2147,13 @@
// If the unthinkable happens, fall through to the safest alternative.
case NPC_ValueDependentIsNull:
- return isTypeDependent() || getType()->isIntegralType(Ctx);
+ if (isTypeDependent() || getType()->isIntegralType(Ctx))
+ return NPCK_ZeroInteger;
+ else
+ return NPCK_NotNull;
case NPC_ValueDependentIsNotNull:
- return false;
+ return NPCK_NotNull;
}
}
@@ -2176,12 +2182,12 @@
return DefaultArg->getExpr()->isNullPointerConstant(Ctx, NPC);
} else if (isa<GNUNullExpr>(this)) {
// The GNU __null extension is always a null pointer constant.
- return true;
+ return NPCK_GNUNull;
}
// C++0x nullptr_t is always a null pointer constant.
if (getType()->isNullPtrType())
- return true;
+ return NPCK_CXX0X_nullptr;
if (const RecordType *UT = getType()->getAsUnionType())
if (UT && UT->getDecl()->hasAttr<TransparentUnionAttr>())
@@ -2193,12 +2199,14 @@
// This expression must be an integer type.
if (!getType()->isIntegerType() ||
(Ctx.getLangOptions().CPlusPlus && getType()->isEnumeralType()))
- return false;
+ return NPCK_NotNull;
// If we have an integer constant expression, we need to *evaluate* it and
// test for the value 0.
llvm::APSInt Result;
- return isIntegerConstantExpr(Result, Ctx) && Result == 0;
+ bool IsNull = isIntegerConstantExpr(Result, Ctx) && Result == 0;
+
+ return (IsNull ? NPCK_ZeroInteger : NPCK_NotNull);
}
/// \brief If this expression is an l-value for an Objective C
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Fri Feb 18 17:54:50 2011
@@ -5229,6 +5229,46 @@
return Owned(expr);
}
+/// \brief Emit a specialized diagnostic when one expression is a null pointer
+/// constant and the other is not a pointer.
+bool Sema::DiagnoseConditionalForNull(Expr *LHS, Expr *RHS,
+ SourceLocation QuestionLoc) {
+ Expr *NullExpr = LHS;
+ Expr *NonPointerExpr = RHS;
+ Expr::NullPointerConstantKind NullKind =
+ NullExpr->isNullPointerConstant(Context,
+ Expr::NPC_ValueDependentIsNotNull);
+
+ if (NullKind == Expr::NPCK_NotNull) {
+ NullExpr = RHS;
+ NonPointerExpr = LHS;
+ NullKind =
+ NullExpr->isNullPointerConstant(Context,
+ Expr::NPC_ValueDependentIsNotNull);
+ }
+
+ if (NullKind == Expr::NPCK_NotNull)
+ return false;
+
+ if (NullKind == Expr::NPCK_ZeroInteger) {
+ // In this case, check to make sure that we got here from a "NULL"
+ // string in the source code.
+ NullExpr = NullExpr->IgnoreParenImpCasts();
+ SourceManager& SM = Context.getSourceManager();
+ SourceLocation Loc = SM.getInstantiationLoc(NullExpr->getExprLoc());
+ unsigned Len =
+ Lexer::MeasureTokenLength(Loc, SM, Context.getLangOptions());
+ if (Len != 4 || memcmp(SM.getCharacterData(Loc), "NULL", 4))
+ return false;
+ }
+
+ int DiagType = (NullKind == Expr::NPCK_CXX0X_nullptr);
+ Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands_null)
+ << NonPointerExpr->getType() << DiagType
+ << NonPointerExpr->getSourceRange();
+ return true;
+}
+
/// Note that lhs is not null here, even if this is the gnu "x ?: y" extension.
/// In that case, lhs = cond.
/// C99 6.5.15
@@ -5471,6 +5511,12 @@
return LHSTy;
}
+ // Emit a better diagnostic if one of the expressions is a null pointer
+ // constant and the other is not a pointer type. In this case, the user most
+ // likely forgot to take the address of the other expression.
+ if (DiagnoseConditionalForNull(LHS, RHS, QuestionLoc))
+ return QualType();
+
// Otherwise, the operands are not compatible.
Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
<< LHSTy << RHSTy << LHS->getSourceRange() << RHS->getSourceRange();
Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Fri Feb 18 17:54:50 2011
@@ -2874,13 +2874,14 @@
/// value operand is a class type, overload resolution is used to find a
/// conversion to a common type.
static bool FindConditionalOverload(Sema &Self, Expr *&LHS, Expr *&RHS,
- SourceLocation Loc) {
+ SourceLocation QuestionLoc) {
Expr *Args[2] = { LHS, RHS };
- OverloadCandidateSet CandidateSet(Loc);
- Self.AddBuiltinOperatorCandidates(OO_Conditional, Loc, Args, 2, CandidateSet);
+ OverloadCandidateSet CandidateSet(QuestionLoc);
+ Self.AddBuiltinOperatorCandidates(OO_Conditional, QuestionLoc, Args, 2,
+ CandidateSet);
OverloadCandidateSet::iterator Best;
- switch (CandidateSet.BestViableFunction(Self, Loc, Best)) {
+ switch (CandidateSet.BestViableFunction(Self, QuestionLoc, Best)) {
case OR_Success:
// We found a match. Perform the conversions on the arguments and move on.
if (Self.PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0],
@@ -2891,13 +2892,20 @@
return false;
case OR_No_Viable_Function:
- Self.Diag(Loc, diag::err_typecheck_cond_incompatible_operands)
+
+ // Emit a better diagnostic if one of the expressions is a null pointer
+ // constant and the other is a pointer type. In this case, the user most
+ // likely forgot to take the address of the other expression.
+ if (Self.DiagnoseConditionalForNull(LHS, RHS, QuestionLoc))
+ return true;
+
+ Self.Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange();
return true;
case OR_Ambiguous:
- Self.Diag(Loc, diag::err_conditional_ambiguous_ovl)
+ Self.Diag(QuestionLoc, diag::err_conditional_ambiguous_ovl)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange();
// FIXME: Print the possible common types by printing the return types of
Modified: cfe/trunk/test/Sema/conditional-expr.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/conditional-expr.c?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/test/Sema/conditional-expr.c (original)
+++ cfe/trunk/test/Sema/conditional-expr.c Fri Feb 18 17:54:50 2011
@@ -75,3 +75,16 @@
// We can suppress this because the immediate context wants an int.
return (x != 0) ? 0U : x;
}
+
+#define NULL (void*)0
+
+void PR9236() {
+ struct A {int i;} A1;
+ (void)(1 ? A1 : NULL); // expected-error{{non-pointer operand type 'struct A' incompatible with NULL}}
+ (void)(1 ? NULL : A1); // expected-error{{non-pointer operand type 'struct A' incompatible with NULL}}
+ (void)(1 ? 0 : A1); // expected-error{{incompatible operand types}}
+ (void)(1 ? (void*)0 : A1); // expected-error{{incompatible operand types}}
+ (void)(1 ? A1: (void*)0); // expected-error{{incompatible operand types}}
+ (void)(1 ? A1 : (NULL)); // expected-error{{non-pointer operand type 'struct A' incompatible with NULL}}
+}
+
Modified: cfe/trunk/test/SemaCXX/__null.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/__null.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/__null.cpp (original)
+++ cfe/trunk/test/SemaCXX/__null.cpp Fri Feb 18 17:54:50 2011
@@ -12,3 +12,10 @@
// Verify that null is evaluated as 0.
int b[__null ? -1 : 1];
}
+
+struct A {};
+
+void g() {
+ (void)(0 ? __null : A()); // expected-error {{non-pointer operand type 'A' incompatible with NULL}}
+ (void)(0 ? A(): __null); // expected-error {{non-pointer operand type 'A' incompatible with NULL}}
+}
Modified: cfe/trunk/test/SemaCXX/conditional-expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/conditional-expr.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/conditional-expr.cpp (original)
+++ cfe/trunk/test/SemaCXX/conditional-expr.cpp Fri Feb 18 17:54:50 2011
@@ -307,3 +307,15 @@
}
}
+
+namespace PR9236 {
+#define NULL 0L
+ void f() {
+ (void)(true ? A() : NULL); // expected-error{{non-pointer operand type 'A' incompatible with NULL}}
+ (void)(true ? NULL : A()); // expected-error{{non-pointer operand type 'A' incompatible with NULL}}
+ (void)(true ? 0 : A()); // expected-error{{incompatible operand types}}
+ (void)(true ? nullptr : A()); // expected-error{{non-pointer operand type 'A' incompatible with nullptr}}
+ (void)(true ? __null : A()); // expected-error{{non-pointer operand type 'A' incompatible with NULL}}
+ (void)(true ? (void*)0 : A()); // expected-error{{incompatible operand types}}
+ }
+}
Modified: cfe/trunk/test/SemaCXX/nullptr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/nullptr.cpp?rev=125995&r1=125994&r2=125995&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/nullptr.cpp (original)
+++ cfe/trunk/test/SemaCXX/nullptr.cpp Fri Feb 18 17:54:50 2011
@@ -46,6 +46,8 @@
(void)(1 + nullptr); // expected-error {{invalid operands to binary expression}}
(void)(0 ? nullptr : 0); // expected-error {{incompatible operand types}}
(void)(0 ? nullptr : (void*)0);
+ (void)(0 ? nullptr : A()); // expected-error {{non-pointer operand type 'A' incompatible with nullptr}}
+ (void)(0 ? A() : nullptr); // expected-error {{non-pointer operand type 'A' incompatible with nullptr}}
// Overloading
int t = o1(nullptr);
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