[cfe-commits] r70829 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/Sema.h lib/Sema/SemaExpr.cpp lib/Sema/SemaExprCXX.cpp test/SemaCXX/composite-pointer-type.cpp test/SemaCXX/elaborated-type-specifier.cpp
Douglas Gregor
dgregor at apple.com
Sun May 3 23:07:13 PDT 2009
Author: dgregor
Date: Mon May 4 01:07:12 2009
New Revision: 70829
URL: http://llvm.org/viewvc/llvm-project?rev=70829&view=rev
Log:
Implement support for comparing pointers with <, >, <=, >=, ==, and !=
in C++, taking into account conversions to the "composite pointer
type" so that we can compare, e.g., a pointer to a derived class to a
pointer to a base class.
Also, upgrade the "comparing distinct pointer types" from a warning to
an error for C++, since this is clearly an error. Turns out that we
hadn't gone through and audited this code for C++, ever.
Fixes <rdar://problem/6816420>.
Added:
cfe/trunk/test/SemaCXX/composite-pointer-type.cpp (with props)
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/Sema.h
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/lib/Sema/SemaExprCXX.cpp
cfe/trunk/test/SemaCXX/elaborated-type-specifier.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=70829&r1=70828&r2=70829&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon May 4 01:07:12 2009
@@ -1039,6 +1039,8 @@
"comparison between pointer and integer (%0 and %1)">;
def ext_typecheck_comparison_of_distinct_pointers : Warning<
"comparison of distinct pointer types (%0 and %1)">;
+def err_typecheck_comparison_of_distinct_pointers : Error<
+ "comparison of distinct pointer types (%0 and %1)">;
def err_typecheck_vector_comparison : Error<
"comparison of vector types (%0 and %1) not supported yet">;
def err_typecheck_assign_const : Error<"read-only variable is not assignable">;
Modified: cfe/trunk/lib/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.h?rev=70829&r1=70828&r2=70829&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/Sema.h (original)
+++ cfe/trunk/lib/Sema/Sema.h Mon May 4 01:07:12 2009
@@ -2424,6 +2424,8 @@
QualType rhsType);
bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);
+ QualType CompositePointerType(Expr *LHS, Expr *RHS,
+ bool LHSIsNull, bool RHSIsNull);
bool PerformImplicitConversion(Expr *&From, QualType ToType,
const char *Flavor,
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=70829&r1=70828&r2=70829&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Mon May 4 01:07:12 2009
@@ -3653,7 +3653,7 @@
return LHSTy;
}
-// C99 6.5.8
+// C99 6.5.8, C++ [expr.rel]
QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
unsigned OpaqueOpc, bool isRelational) {
BinaryOperator::Opcode Opc = (BinaryOperator::Opcode)OpaqueOpc;
@@ -3758,6 +3758,31 @@
QualType RCanPointeeTy =
Context.getCanonicalType(rType->getAsPointerType()->getPointeeType());
+ // Simple check: if the pointee types are identical, we're done.
+ if (LCanPointeeTy == RCanPointeeTy)
+ return ResultTy;
+
+ if (getLangOptions().CPlusPlus) {
+ // C++ [expr.rel]p2:
+ // [...] Pointer conversions (4.10) and qualification
+ // conversions (4.4) are performed on pointer operands (or on
+ // a pointer operand and a null pointer constant) to bring
+ // them to their composite pointer type. [...]
+ //
+ // C++ [expr.eq]p2 uses the same notion for (in)equality
+ // comparisons of pointers.
+ QualType T = CompositePointerType(lex, rex, LHSIsNull, RHSIsNull);
+ if (T.isNull()) {
+ Diag(Loc, diag::err_typecheck_comparison_of_distinct_pointers)
+ << lType << rType << lex->getSourceRange() << rex->getSourceRange();
+ return QualType();
+ }
+
+ ImpCastExprToType(lex, T);
+ ImpCastExprToType(rex, T);
+ return ResultTy;
+ }
+
if (!LHSIsNull && !RHSIsNull && // C99 6.5.9p2
!LCanPointeeTy->isVoidType() && !RCanPointeeTy->isVoidType() &&
!Context.typesAreCompatible(LCanPointeeTy.getUnqualifiedType(),
Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=70829&r1=70828&r2=70829&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Mon May 4 01:07:12 2009
@@ -768,6 +768,77 @@
return false;
}
+/// \brief Determine the composite pointer type (C++ [expr.rel]p2)
+/// given the left- and right-hand expressions in a relational
+/// operation.
+///
+/// While the notion of a composite pointer type is only described for
+/// relational operators (<, >, <=, >=), the same computation is used
+/// to determine the "common type" used for the equality operators
+/// (==, !=) when comparing pointers.
+///
+/// \param LHS the left-hand operand.
+/// \param RHS the right-hand operand.
+/// \param LHSIsNull whether \p LHS is the NULL pointer constant
+/// \param RHSIsNull whether \p RHS is the NULL pointer constant
+///
+/// \returns the composite pointer type, if any, or the null type if
+/// no such type exists. It is the caller's responsibility to emit
+/// diagnostic.
+QualType Sema::CompositePointerType(Expr *LHS, Expr *RHS,
+ bool LHSIsNull, bool RHSIsNull) {
+ // First, determine whether LHS and RHS have pointer types, and what
+ // types they point to.
+ QualType LHSPointee;
+ QualType RHSPointee;
+ if (const PointerType *LHSPtr = LHS->getType()->getAsPointerType())
+ LHSPointee = LHSPtr->getPointeeType();
+ if (const PointerType *RHSPtr = RHS->getType()->getAsPointerType())
+ RHSPointee = RHSPtr->getPointeeType();
+
+ // C++ [expr.rel]p2:
+ // [...] If one operand is a null pointer constant, the composite
+ // pointer type is the type of the other operand.
+ if (LHSIsNull && !RHSPointee.isNull())
+ return RHS->getType();
+ if (RHSIsNull && !LHSPointee.isNull())
+ return LHS->getType();
+
+ // If neither LHS nor RHS has pointer type, we're done.
+ if (LHSPointee.isNull() && RHSPointee.isNull())
+ return QualType();
+
+ // [...] Otherwise, if one of the operands has type "pointer to cv1
+ // void", then the other has type "pointer to cv2 T" and the
+ // composite pointer type is "pointer to cv12 void", where cv12 is
+ // the union of cv1 and cv2.
+ QualType LHSPointeeCanon = Context.getCanonicalType(LHSPointee);
+ QualType RHSPointeeCanon = Context.getCanonicalType(RHSPointee);
+ unsigned CVQuals =
+ (LHSPointeeCanon.getCVRQualifiers() | RHSPointeeCanon.getCVRQualifiers());
+ if (LHSPointeeCanon->isVoidType() || RHSPointeeCanon->isVoidType())
+ return Context.getPointerType(Context.VoidTy.getQualifiedType(CVQuals));
+
+ // [...] Otherwise, the composite pointer type is a pointer type
+ // similar (4.4) to the type of one of the operands, with a
+ // cv-qualification signature (4.4) that is the union of the
+ // cv-qualification signatures of the operand types.
+ QualType FullyQualifiedLHSType
+ = Context.getPointerType(LHSPointee.getQualifiedType(CVQuals));
+ QualType CompositePointerType;
+ bool IncompatibleObjC = false;
+ if (IsPointerConversion(RHS, RHS->getType(), FullyQualifiedLHSType,
+ CompositePointerType, IncompatibleObjC))
+ return CompositePointerType;
+ QualType FullyQualifiedRHSType
+ = Context.getPointerType(RHSPointee.getQualifiedType(CVQuals));
+ if (IsPointerConversion(LHS, LHS->getType(), FullyQualifiedRHSType,
+ CompositePointerType, IncompatibleObjC))
+ return CompositePointerType;
+
+ return QualType();
+}
+
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType. Returns true if there was an
/// error, false otherwise. The expression From is replaced with the
Added: cfe/trunk/test/SemaCXX/composite-pointer-type.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/composite-pointer-type.cpp?rev=70829&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/composite-pointer-type.cpp (added)
+++ cfe/trunk/test/SemaCXX/composite-pointer-type.cpp Mon May 4 01:07:12 2009
@@ -0,0 +1,27 @@
+// RUN: clang-cc -fsyntax-only -verify %s
+
+class Base { };
+class Derived1 : public Base { };
+class Derived2 : public Base { };
+
+void f0(volatile Base *b, Derived1 *d1, const Derived2 *d2) {
+ if (b > d1)
+ return;
+ if (d1 <= b)
+ return;
+ if (b > d2)
+ return;
+ if (d1 >= d2) // expected-error{{comparison of distinct}}
+ return;
+}
+
+void f1(volatile Base *b, Derived1 *d1, const Derived2 *d2) {
+ if (b == d1)
+ return;
+ if (d1 == b)
+ return;
+ if (b != d2)
+ return;
+ if (d1 == d2) // expected-error{{comparison of distinct}}
+ return;
+}
Propchange: cfe/trunk/test/SemaCXX/composite-pointer-type.cpp
------------------------------------------------------------------------------
svn:eol-style = native
Propchange: cfe/trunk/test/SemaCXX/composite-pointer-type.cpp
------------------------------------------------------------------------------
svn:keywords = Id
Propchange: cfe/trunk/test/SemaCXX/composite-pointer-type.cpp
------------------------------------------------------------------------------
svn:mime-type = text/plain
Modified: cfe/trunk/test/SemaCXX/elaborated-type-specifier.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/elaborated-type-specifier.cpp?rev=70829&r1=70828&r2=70829&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/elaborated-type-specifier.cpp (original)
+++ cfe/trunk/test/SemaCXX/elaborated-type-specifier.cpp Mon May 4 01:07:12 2009
@@ -38,10 +38,9 @@
S4 *s4; // expected-error{{use of undeclared identifier 'S4'}}
}
-// FIXME: the warning below should be an error!
int test_funcparam_scope(struct S5 * s5) {
struct S5 { int y; } *s5_2 = 0;
- if (s5 == s5_2) return 1; // expected-warning {{comparison of distinct pointer types ('struct S5 *' and 'struct S5 *')}}
+ if (s5 == s5_2) return 1; // expected-error {{comparison of distinct pointer types ('struct S5 *' and 'struct S5 *')}}
return 0;
}
More information about the cfe-commits
mailing list