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llvm-project/clang/lib/Sema/SemaExprCXX.cpp
Chris Lattner 1e5665e6be Change a whole lot of diagnostics to take QualType's directly 
instead of converting them to strings first.  This also fixes a
bunch of minor inconsistencies in the diagnostics emitted by clang
and adds a bunch of FIXME's to DiagnosticKinds.def.

llvm-svn: 59948
2008-11-24 06:25:27 +00:00

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//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for C++ expressions.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ASTContext.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/Diagnostic.h"
using namespace clang;
/// ActOnCXXConversionFunctionExpr - Parse a C++ conversion function
/// name (e.g., operator void const *) as an expression. This is
/// very similar to ActOnIdentifierExpr, except that instead of
/// providing an identifier the parser provides the type of the
/// conversion function.
Sema::ExprResult
Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc,
TypeTy *Ty, bool HasTrailingLParen,
const CXXScopeSpec &SS) {
QualType ConvType = QualType::getFromOpaquePtr(Ty);
QualType ConvTypeCanon = Context.getCanonicalType(ConvType);
DeclarationName ConvName
= Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon);
return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen,
&SS);
}
/// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator
/// name (e.g., @c operator+ ) as an expression. This is very
/// similar to ActOnIdentifierExpr, except that instead of providing
/// an identifier the parser provides the kind of overloaded
/// operator that was parsed.
Sema::ExprResult
Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc,
OverloadedOperatorKind Op,
bool HasTrailingLParen,
const CXXScopeSpec &SS) {
DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op);
return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS);
}
/// ActOnCXXTypeidOfType - Parse typeid( type-id ).
Action::ExprResult
Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
const NamespaceDecl *StdNs = GetStdNamespace();
if (!StdNs)
return Diag(OpLoc, diag::err_need_header_before_typeid);
IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
Decl *TypeInfoDecl = LookupDecl(TypeInfoII,
Decl::IDNS_Tag | Decl::IDNS_Ordinary,
0, StdNs, /*createBuiltins=*/false);
RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null<RecordDecl>(TypeInfoDecl);
if (!TypeInfoRecordDecl)
return Diag(OpLoc, diag::err_need_header_before_typeid);
QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl);
return new CXXTypeidExpr(isType, TyOrExpr, TypeInfoType.withConst(),
SourceRange(OpLoc, RParenLoc));
}
/// ActOnCXXBoolLiteral - Parse {true,false} literals.
Action::ExprResult
Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
"Unknown C++ Boolean value!");
return new CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc);
}
/// ActOnCXXThrow - Parse throw expressions.
Action::ExprResult
Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprTy *E) {
return new CXXThrowExpr((Expr*)E, Context.VoidTy, OpLoc);
}
Action::ExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) {
/// C++ 9.3.2: In the body of a non-static member function, the keyword this
/// is a non-lvalue expression whose value is the address of the object for
/// which the function is called.
if (!isa<FunctionDecl>(CurContext)) {
Diag(ThisLoc, diag::err_invalid_this_use);
return ExprResult(true);
}
if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext))
if (MD->isInstance())
return new CXXThisExpr(ThisLoc, MD->getThisType(Context));
return Diag(ThisLoc, diag::err_invalid_this_use);
}
/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
Action::ExprResult
Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep,
SourceLocation LParenLoc,
ExprTy **ExprTys, unsigned NumExprs,
SourceLocation *CommaLocs,
SourceLocation RParenLoc) {
assert(TypeRep && "Missing type!");
QualType Ty = QualType::getFromOpaquePtr(TypeRep);
Expr **Exprs = (Expr**)ExprTys;
SourceLocation TyBeginLoc = TypeRange.getBegin();
SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc);
if (const RecordType *RT = Ty->getAsRecordType()) {
// C++ 5.2.3p1:
// If the simple-type-specifier specifies a class type, the class type shall
// be complete.
//
if (!RT->getDecl()->isDefinition())
return Diag(TyBeginLoc, diag::err_invalid_incomplete_type_use)
<< Ty << FullRange;
unsigned DiagID = PP.getDiagnostics().getCustomDiagID(Diagnostic::Error,
"class constructors are not supported yet");
return Diag(TyBeginLoc, DiagID);
}
// C++ 5.2.3p1:
// If the expression list is a single expression, the type conversion
// expression is equivalent (in definedness, and if defined in meaning) to the
// corresponding cast expression.
//
if (NumExprs == 1) {
if (CheckCastTypes(TypeRange, Ty, Exprs[0]))
return true;
return new CXXFunctionalCastExpr(Ty.getNonReferenceType(), Ty, TyBeginLoc,
Exprs[0], RParenLoc);
}
// C++ 5.2.3p1:
// If the expression list specifies more than a single value, the type shall
// be a class with a suitably declared constructor.
//
if (NumExprs > 1)
return Diag(CommaLocs[0], diag::err_builtin_func_cast_more_than_one_arg)
<< FullRange;
assert(NumExprs == 0 && "Expected 0 expressions");
// C++ 5.2.3p2:
// The expression T(), where T is a simple-type-specifier for a non-array
// complete object type or the (possibly cv-qualified) void type, creates an
// rvalue of the specified type, which is value-initialized.
//
if (Ty->isArrayType())
return Diag(TyBeginLoc, diag::err_value_init_for_array_type) << FullRange;
if (Ty->isIncompleteType() && !Ty->isVoidType())
return Diag(TyBeginLoc, diag::err_invalid_incomplete_type_use)
<< Ty << FullRange;
return new CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc);
}
/// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.:
/// @code new (memory) int[size][4] @endcode
/// or
/// @code ::new Foo(23, "hello") @endcode
/// For the interpretation of this heap of arguments, consult the base version.
Action::ExprResult
Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
SourceLocation PlacementLParen,
ExprTy **PlacementArgs, unsigned NumPlaceArgs,
SourceLocation PlacementRParen, bool ParenTypeId,
SourceLocation TyStart, TypeTy *Ty, SourceLocation TyEnd,
SourceLocation ConstructorLParen,
ExprTy **ConstructorArgs, unsigned NumConsArgs,
SourceLocation ConstructorRParen)
{
QualType AllocType = QualType::getFromOpaquePtr(Ty);
QualType CheckType = AllocType;
// To leverage the existing parser as much as possible, array types are
// parsed as VLAs. Unwrap for checking.
if (const VariableArrayType *VLA = Context.getAsVariableArrayType(AllocType))
CheckType = VLA->getElementType();
// Validate the type, and unwrap an array if any.
if (CheckAllocatedType(CheckType, StartLoc, SourceRange(TyStart, TyEnd)))
return true;
QualType ResultType = Context.getPointerType(CheckType);
// That every array dimension except the first is constant was already
// checked by the type check above.
// C++ 5.3.4p6: "The expression in a direct-new-declarator shall have integral
// or enumeration type with a non-negative value."
// This was checked by ActOnTypeName, since C99 has the same restriction on
// VLA expressions.
// --- Choosing an allocation function ---
// C++ 5.3.4p8 - 14 & 18
// 1) If UseGlobal is true, only look in the global scope. Else, also look
// in the scope of the allocated class.
// 2) If an array size is given, look for operator new[], else look for
// operator new.
// 3) The first argument is always size_t. Append the arguments from the
// placement form.
// FIXME: Find the correct overload of operator new.
// FIXME: Also find the corresponding overload of operator delete.
FunctionDecl *OperatorNew = 0;
FunctionDecl *OperatorDelete = 0;
Expr **PlaceArgs = (Expr**)PlacementArgs;
bool Init = ConstructorLParen.isValid();
// --- Choosing a constructor ---
// C++ 5.3.4p15
// 1) If T is a POD and there's no initializer (ConstructorLParen is invalid)
// the object is not initialized. If the object, or any part of it, is
// const-qualified, it's an error.
// 2) If T is a POD and there's an empty initializer, the object is value-
// initialized.
// 3) If T is a POD and there's one initializer argument, the object is copy-
// constructed.
// 4) If T is a POD and there's more initializer arguments, it's an error.
// 5) If T is not a POD, the initializer arguments are used as constructor
// arguments.
//
// Or by the C++0x formulation:
// 1) If there's no initializer, the object is default-initialized according
// to C++0x rules.
// 2) Otherwise, the object is direct-initialized.
CXXConstructorDecl *Constructor = 0;
Expr **ConsArgs = (Expr**)ConstructorArgs;
if (const RecordType *RT = CheckType->getAsRecordType()) {
// FIXME: This is incorrect for when there is an empty initializer and
// no user-defined constructor. Must zero-initialize, not default-construct.
Constructor = PerformInitializationByConstructor(
CheckType, ConsArgs, NumConsArgs,
TyStart, SourceRange(TyStart, ConstructorRParen),
RT->getDecl()->getDeclName(),
NumConsArgs != 0 ? IK_Direct : IK_Default);
if (!Constructor)
return true;
} else {
if (!Init) {
// FIXME: Check that no subpart is const.
if (CheckType.isConstQualified()) {
Diag(StartLoc, diag::err_new_uninitialized_const)
<< SourceRange(StartLoc, TyEnd);
return true;
}
} else if (NumConsArgs == 0) {
// Object is value-initialized. Do nothing.
} else if (NumConsArgs == 1) {
// Object is direct-initialized.
// FIXME: WHAT DeclarationName do we pass in here?
if (CheckInitializerTypes(ConsArgs[0], CheckType, StartLoc,
DeclarationName() /*CheckType.getAsString()*/))
return true;
} else {
Diag(StartLoc, diag::err_builtin_direct_init_more_than_one_arg)
<< SourceRange(ConstructorLParen, ConstructorRParen);
}
}
// FIXME: Also check that the destructor is accessible. (C++ 5.3.4p16)
return new CXXNewExpr(UseGlobal, OperatorNew, PlaceArgs, NumPlaceArgs,
ParenTypeId, AllocType, Constructor, Init,
ConsArgs, NumConsArgs, OperatorDelete, ResultType,
StartLoc, Init ? ConstructorRParen : TyEnd);
}
/// CheckAllocatedType - Checks that a type is suitable as the allocated type
/// in a new-expression.
/// dimension off and stores the size expression in ArraySize.
bool Sema::CheckAllocatedType(QualType AllocType, SourceLocation StartLoc,
const SourceRange &TyR)
{
// C++ 5.3.4p1: "[The] type shall be a complete object type, but not an
// abstract class type or array thereof.
// FIXME: We don't have abstract types yet.
// FIXME: Under C++ semantics, an incomplete object type is still an object
// type. This code assumes the C semantics, where it's not.
if (!AllocType->isObjectType()) {
diag::kind msg;
if (AllocType->isFunctionType()) {
msg = diag::err_new_function;
} else if(AllocType->isIncompleteType()) {
msg = diag::err_new_incomplete;
} else if(AllocType->isReferenceType()) {
msg = diag::err_new_reference;
} else {
assert(false && "Unexpected type class");
return true;
}
Diag(StartLoc, msg) << AllocType << TyR;
return true;
}
// Every dimension beyond the first shall be of constant size.
while (const ArrayType *Array = Context.getAsArrayType(AllocType)) {
if (!Array->isConstantArrayType()) {
// FIXME: Might be nice to get a better source range from somewhere.
Diag(StartLoc, diag::err_new_array_nonconst) << TyR;
return true;
}
AllocType = Array->getElementType();
}
return false;
}
/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
/// @code ::delete ptr; @endcode
/// or
/// @code delete [] ptr; @endcode
Action::ExprResult
Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
bool ArrayForm, ExprTy *Operand)
{
// C++ 5.3.5p1: "The operand shall have a pointer type, or a class type
// having a single conversion function to a pointer type. The result has
// type void."
// DR599 amends "pointer type" to "pointer to object type" in both cases.
Expr *Ex = (Expr *)Operand;
QualType Type = Ex->getType();
if (Type->isRecordType()) {
// FIXME: Find that one conversion function and amend the type.
}
if (!Type->isPointerType()) {
Diag(StartLoc, diag::err_delete_operand) << Type << Ex->getSourceRange();
return true;
}
QualType Pointee = Type->getAsPointerType()->getPointeeType();
if (Pointee->isIncompleteType() && !Pointee->isVoidType())
Diag(StartLoc, diag::warn_delete_incomplete)
<< Pointee << Ex->getSourceRange();
else if (!Pointee->isObjectType()) {
Diag(StartLoc, diag::err_delete_operand)
<< Type << Ex->getSourceRange();
return true;
}
// FIXME: Look up the correct operator delete overload and pass a pointer
// along.
// FIXME: Check access and ambiguity of operator delete and destructor.
return new CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm, 0, Ex,
StartLoc);
}
/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
/// C++ if/switch/while/for statement.
/// e.g: "if (int x = f()) {...}"
Action::ExprResult
Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc,
Declarator &D,
SourceLocation EqualLoc,
ExprTy *AssignExprVal) {
assert(AssignExprVal && "Null assignment expression");
// C++ 6.4p2:
// The declarator shall not specify a function or an array.
// The type-specifier-seq shall not contain typedef and shall not declare a
// new class or enumeration.
assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
"Parser allowed 'typedef' as storage class of condition decl.");
QualType Ty = GetTypeForDeclarator(D, S);
if (Ty->isFunctionType()) { // The declarator shall not specify a function...
// We exit without creating a CXXConditionDeclExpr because a FunctionDecl
// would be created and CXXConditionDeclExpr wants a VarDecl.
return Diag(StartLoc, diag::err_invalid_use_of_function_type)
<< SourceRange(StartLoc, EqualLoc);
} else if (Ty->isArrayType()) { // ...or an array.
Diag(StartLoc, diag::err_invalid_use_of_array_type)
<< SourceRange(StartLoc, EqualLoc);
} else if (const RecordType *RT = Ty->getAsRecordType()) {
RecordDecl *RD = RT->getDecl();
// The type-specifier-seq shall not declare a new class...
if (RD->isDefinition() && (RD->getIdentifier() == 0 || S->isDeclScope(RD)))
Diag(RD->getLocation(), diag::err_type_defined_in_condition);
} else if (const EnumType *ET = Ty->getAsEnumType()) {
EnumDecl *ED = ET->getDecl();
// ...or enumeration.
if (ED->isDefinition() && (ED->getIdentifier() == 0 || S->isDeclScope(ED)))
Diag(ED->getLocation(), diag::err_type_defined_in_condition);
}
DeclTy *Dcl = ActOnDeclarator(S, D, 0);
if (!Dcl)
return true;
AddInitializerToDecl(Dcl, AssignExprVal);
return new CXXConditionDeclExpr(StartLoc, EqualLoc,
cast<VarDecl>(static_cast<Decl *>(Dcl)));
}
/// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
bool Sema::CheckCXXBooleanCondition(Expr *&CondExpr) {
// C++ 6.4p4:
// The value of a condition that is an initialized declaration in a statement
// other than a switch statement is the value of the declared variable
// implicitly converted to type bool. If that conversion is ill-formed, the
// program is ill-formed.
// The value of a condition that is an expression is the value of the
// expression, implicitly converted to bool.
//
QualType Ty = CondExpr->getType(); // Save the type.
AssignConvertType
ConvTy = CheckSingleAssignmentConstraints(Context.BoolTy, CondExpr);
if (ConvTy == Incompatible)
return Diag(CondExpr->getLocStart(), diag::err_typecheck_bool_condition)
<< Ty << CondExpr->getSourceRange();
return false;
}
/// Helper function to determine whether this is the (deprecated) C++
/// conversion from a string literal to a pointer to non-const char or
/// non-const wchar_t (for narrow and wide string literals,
/// respectively).
bool
Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
// Look inside the implicit cast, if it exists.
if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
From = Cast->getSubExpr();
// A string literal (2.13.4) that is not a wide string literal can
// be converted to an rvalue of type "pointer to char"; a wide
// string literal can be converted to an rvalue of type "pointer
// to wchar_t" (C++ 4.2p2).
if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From))
if (const PointerType *ToPtrType = ToType->getAsPointerType())
if (const BuiltinType *ToPointeeType
= ToPtrType->getPointeeType()->getAsBuiltinType()) {
// This conversion is considered only when there is an
// explicit appropriate pointer target type (C++ 4.2p2).
if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 &&
((StrLit->isWide() && ToPointeeType->isWideCharType()) ||
(!StrLit->isWide() &&
(ToPointeeType->getKind() == BuiltinType::Char_U ||
ToPointeeType->getKind() == BuiltinType::Char_S))))
return true;
}
return false;
}
/// 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
/// converted expression.
bool
Sema::PerformImplicitConversion(Expr *&From, QualType ToType)
{
ImplicitConversionSequence ICS = TryImplicitConversion(From, ToType);
switch (ICS.ConversionKind) {
case ImplicitConversionSequence::StandardConversion:
if (PerformImplicitConversion(From, ToType, ICS.Standard))
return true;
break;
case ImplicitConversionSequence::UserDefinedConversion:
// FIXME: This is, of course, wrong. We'll need to actually call
// the constructor or conversion operator, and then cope with the
// standard conversions.
ImpCastExprToType(From, ToType);
return false;
case ImplicitConversionSequence::EllipsisConversion:
assert(false && "Cannot perform an ellipsis conversion");
return false;
case ImplicitConversionSequence::BadConversion:
return true;
}
// Everything went well.
return false;
}
/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType by following the standard
/// conversion sequence SCS. Returns true if there was an error, false
/// otherwise. The expression From is replaced with the converted
/// expression.
bool
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
const StandardConversionSequence& SCS)
{
// Overall FIXME: we are recomputing too many types here and doing
// far too much extra work. What this means is that we need to keep
// track of more information that is computed when we try the
// implicit conversion initially, so that we don't need to recompute
// anything here.
QualType FromType = From->getType();
if (SCS.CopyConstructor) {
// FIXME: Create a temporary object by calling the copy
// constructor.
ImpCastExprToType(From, ToType);
return false;
}
// Perform the first implicit conversion.
switch (SCS.First) {
case ICK_Identity:
case ICK_Lvalue_To_Rvalue:
// Nothing to do.
break;
case ICK_Array_To_Pointer:
if (FromType->isOverloadType()) {
FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true);
if (!Fn)
return true;
FixOverloadedFunctionReference(From, Fn);
FromType = From->getType();
} else {
FromType = Context.getArrayDecayedType(FromType);
}
ImpCastExprToType(From, FromType);
break;
case ICK_Function_To_Pointer:
FromType = Context.getPointerType(FromType);
ImpCastExprToType(From, FromType);
break;
default:
assert(false && "Improper first standard conversion");
break;
}
// Perform the second implicit conversion
switch (SCS.Second) {
case ICK_Identity:
// Nothing to do.
break;
case ICK_Integral_Promotion:
case ICK_Floating_Promotion:
case ICK_Integral_Conversion:
case ICK_Floating_Conversion:
case ICK_Floating_Integral:
FromType = ToType.getUnqualifiedType();
ImpCastExprToType(From, FromType);
break;
case ICK_Pointer_Conversion:
if (CheckPointerConversion(From, ToType))
return true;
ImpCastExprToType(From, ToType);
break;
case ICK_Pointer_Member:
// FIXME: Implement pointer-to-member conversions.
assert(false && "Pointer-to-member conversions are unsupported");
break;
case ICK_Boolean_Conversion:
FromType = Context.BoolTy;
ImpCastExprToType(From, FromType);
break;
default:
assert(false && "Improper second standard conversion");
break;
}
switch (SCS.Third) {
case ICK_Identity:
// Nothing to do.
break;
case ICK_Qualification:
ImpCastExprToType(From, ToType);
break;
default:
assert(false && "Improper second standard conversion");
break;
}
return false;
}
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