Preliminary support for function overloading
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57909 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
new file mode 100644
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--- /dev/null
+++ b/lib/Sema/SemaOverload.cpp
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+//===--- SemaOverload.cpp - C++ Overloading ---------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides Sema routines for C++ overloading.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sema.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
+#include "llvm/Support/Compiler.h"
+#include <algorithm>
+
+namespace clang {
+
+/// GetConversionCategory - Retrieve the implicit conversion
+/// category corresponding to the given implicit conversion kind.
+ImplicitConversionCategory
+GetConversionCategory(ImplicitConversionKind Kind) {
+ static const ImplicitConversionCategory
+ Category[(int)ICK_Num_Conversion_Kinds] = {
+ ICC_Identity,
+ ICC_Lvalue_Transformation,
+ ICC_Lvalue_Transformation,
+ ICC_Lvalue_Transformation,
+ ICC_Qualification_Adjustment,
+ ICC_Promotion,
+ ICC_Promotion,
+ ICC_Conversion,
+ ICC_Conversion,
+ ICC_Conversion,
+ ICC_Conversion,
+ ICC_Conversion,
+ ICC_Conversion
+ };
+ return Category[(int)Kind];
+}
+
+/// GetConversionRank - Retrieve the implicit conversion rank
+/// corresponding to the given implicit conversion kind.
+ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) {
+ static const ImplicitConversionRank
+ Rank[(int)ICK_Num_Conversion_Kinds] = {
+ ICR_Exact_Match,
+ ICR_Exact_Match,
+ ICR_Exact_Match,
+ ICR_Exact_Match,
+ ICR_Exact_Match,
+ ICR_Promotion,
+ ICR_Promotion,
+ ICR_Conversion,
+ ICR_Conversion,
+ ICR_Conversion,
+ ICR_Conversion,
+ ICR_Conversion,
+ ICR_Conversion
+ };
+ return Rank[(int)Kind];
+}
+
+/// GetImplicitConversionName - Return the name of this kind of
+/// implicit conversion.
+const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
+ static const char* Name[(int)ICK_Num_Conversion_Kinds] = {
+ "No conversion",
+ "Lvalue-to-rvalue",
+ "Array-to-pointer",
+ "Function-to-pointer",
+ "Qualification",
+ "Integral promotion",
+ "Floating point promotion",
+ "Integral conversion",
+ "Floating conversion",
+ "Floating-integral conversion",
+ "Pointer conversion",
+ "Pointer-to-member conversion",
+ "Boolean conversion"
+ };
+ return Name[Kind];
+}
+
+/// getRank - Retrieve the rank of this standard conversion sequence
+/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
+/// implicit conversions.
+ImplicitConversionRank StandardConversionSequence::getRank() const {
+ ImplicitConversionRank Rank = ICR_Exact_Match;
+ if (GetConversionRank(First) > Rank)
+ Rank = GetConversionRank(First);
+ if (GetConversionRank(Second) > Rank)
+ Rank = GetConversionRank(Second);
+ if (GetConversionRank(Third) > Rank)
+ Rank = GetConversionRank(Third);
+ return Rank;
+}
+
+/// isPointerConversionToBool - Determines whether this conversion is
+/// a conversion of a pointer or pointer-to-member to bool. This is
+/// used as part of the ranking of standard conversion sequences
+/// (C++ 13.3.3.2p4).
+bool StandardConversionSequence::isPointerConversionToBool() const
+{
+ QualType FromType = QualType::getFromOpaquePtr(FromTypePtr);
+ QualType ToType = QualType::getFromOpaquePtr(ToTypePtr);
+
+ // Note that FromType has not necessarily been transformed by the
+ // array-to-pointer or function-to-pointer implicit conversions, so
+ // check for their presence as well as checking whether FromType is
+ // a pointer.
+ if (ToType->isBooleanType() &&
+ (FromType->isPointerType() ||
+ First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
+ return true;
+
+ return false;
+}
+
+/// DebugPrint - Print this standard conversion sequence to standard
+/// error. Useful for debugging overloading issues.
+void StandardConversionSequence::DebugPrint() const {
+ bool PrintedSomething = false;
+ if (First != ICK_Identity) {
+ fprintf(stderr, "%s", GetImplicitConversionName(First));
+ PrintedSomething = true;
+ }
+
+ if (Second != ICK_Identity) {
+ if (PrintedSomething) {
+ fprintf(stderr, " -> ");
+ }
+ fprintf(stderr, "%s", GetImplicitConversionName(Second));
+ PrintedSomething = true;
+ }
+
+ if (Third != ICK_Identity) {
+ if (PrintedSomething) {
+ fprintf(stderr, " -> ");
+ }
+ fprintf(stderr, "%s", GetImplicitConversionName(Third));
+ PrintedSomething = true;
+ }
+
+ if (!PrintedSomething) {
+ fprintf(stderr, "No conversions required");
+ }
+}
+
+/// DebugPrint - Print this user-defined conversion sequence to standard
+/// error. Useful for debugging overloading issues.
+void UserDefinedConversionSequence::DebugPrint() const {
+ if (Before.First || Before.Second || Before.Third) {
+ Before.DebugPrint();
+ fprintf(stderr, " -> ");
+ }
+ fprintf(stderr, "'%s'", ConversionFunction->getName());
+ if (After.First || After.Second || After.Third) {
+ fprintf(stderr, " -> ");
+ After.DebugPrint();
+ }
+}
+
+/// DebugPrint - Print this implicit conversion sequence to standard
+/// error. Useful for debugging overloading issues.
+void ImplicitConversionSequence::DebugPrint() const {
+ switch (ConversionKind) {
+ case StandardConversion:
+ fprintf(stderr, "Standard conversion: ");
+ Standard.DebugPrint();
+ break;
+ case UserDefinedConversion:
+ fprintf(stderr, "User-defined conversion: ");
+ UserDefined.DebugPrint();
+ break;
+ case EllipsisConversion:
+ fprintf(stderr, "Ellipsis conversion");
+ break;
+ case BadConversion:
+ fprintf(stderr, "Bad conversion");
+ break;
+ }
+
+ fprintf(stderr, "\n");
+}
+
+// IsOverload - Determine whether the given New declaration is an
+// overload of the Old declaration. This routine returns false if New
+// and Old cannot be overloaded, e.g., if they are functions with the
+// same signature (C++ 1.3.10) or if the Old declaration isn't a
+// function (or overload set). When it does return false and Old is an
+// OverloadedFunctionDecl, MatchedDecl will be set to point to the
+// FunctionDecl that New cannot be overloaded with.
+//
+// Example: Given the following input:
+//
+// void f(int, float); // #1
+// void f(int, int); // #2
+// int f(int, int); // #3
+//
+// When we process #1, there is no previous declaration of "f",
+// so IsOverload will not be used.
+//
+// When we process #2, Old is a FunctionDecl for #1. By comparing the
+// parameter types, we see that #1 and #2 are overloaded (since they
+// have different signatures), so this routine returns false;
+// MatchedDecl is unchanged.
+//
+// When we process #3, Old is an OverloadedFunctionDecl containing #1
+// and #2. We compare the signatures of #3 to #1 (they're overloaded,
+// so we do nothing) and then #3 to #2. Since the signatures of #3 and
+// #2 are identical (return types of functions are not part of the
+// signature), IsOverload returns false and MatchedDecl will be set to
+// point to the FunctionDecl for #2.
+bool
+Sema::IsOverload(FunctionDecl *New, Decl* OldD,
+ OverloadedFunctionDecl::function_iterator& MatchedDecl)
+{
+ if (OverloadedFunctionDecl* Ovl = dyn_cast<OverloadedFunctionDecl>(OldD)) {
+ // Is this new function an overload of every function in the
+ // overload set?
+ OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(),
+ FuncEnd = Ovl->function_end();
+ for (; Func != FuncEnd; ++Func) {
+ if (!IsOverload(New, *Func, MatchedDecl)) {
+ MatchedDecl = Func;
+ return false;
+ }
+ }
+
+ // This function overloads every function in the overload set.
+ return true;
+ } else if (FunctionDecl* Old = dyn_cast<FunctionDecl>(OldD)) {
+ // Is the function New an overload of the function Old?
+ QualType OldQType = Context.getCanonicalType(Old->getType());
+ QualType NewQType = Context.getCanonicalType(New->getType());
+
+ // Compare the signatures (C++ 1.3.10) of the two functions to
+ // determine whether they are overloads. If we find any mismatch
+ // in the signature, they are overloads.
+
+ // If either of these functions is a K&R-style function (no
+ // prototype), then we consider them to have matching signatures.
+ if (isa<FunctionTypeNoProto>(OldQType.getTypePtr()) ||
+ isa<FunctionTypeNoProto>(NewQType.getTypePtr()))
+ return false;
+
+ FunctionTypeProto* OldType = cast<FunctionTypeProto>(OldQType.getTypePtr());
+ FunctionTypeProto* NewType = cast<FunctionTypeProto>(NewQType.getTypePtr());
+
+ // The signature of a function includes the types of its
+ // parameters (C++ 1.3.10), which includes the presence or absence
+ // of the ellipsis; see C++ DR 357).
+ if (OldQType != NewQType &&
+ (OldType->getNumArgs() != NewType->getNumArgs() ||
+ OldType->isVariadic() != NewType->isVariadic() ||
+ !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(),
+ NewType->arg_type_begin())))
+ return true;
+
+ // If the function is a class member, its signature includes the
+ // cv-qualifiers (if any) on the function itself.
+ //
+ // As part of this, also check whether one of the member functions
+ // is static, in which case they are not overloads (C++
+ // 13.1p2). While not part of the definition of the signature,
+ // this check is important to determine whether these functions
+ // can be overloaded.
+ CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old);
+ CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New);
+ if (OldMethod && NewMethod &&
+ !OldMethod->isStatic() && !NewMethod->isStatic() &&
+ OldQType.getCVRQualifiers() != NewQType.getCVRQualifiers())
+ return true;
+
+ // The signatures match; this is not an overload.
+ return false;
+ } else {
+ // (C++ 13p1):
+ // Only function declarations can be overloaded; object and type
+ // declarations cannot be overloaded.
+ return false;
+ }
+}
+
+/// TryCopyInitialization - Attempt to copy-initialize a value of the
+/// given type (ToType) from the given expression (Expr), as one would
+/// do when copy-initializing a function parameter. This function
+/// returns an implicit conversion sequence that can be used to
+/// perform the initialization. Given
+///
+/// void f(float f);
+/// void g(int i) { f(i); }
+///
+/// this routine would produce an implicit conversion sequence to
+/// describe the initialization of f from i, which will be a standard
+/// conversion sequence containing an lvalue-to-rvalue conversion (C++
+/// 4.1) followed by a floating-integral conversion (C++ 4.9).
+//
+/// Note that this routine only determines how the conversion can be
+/// performed; it does not actually perform the conversion. As such,
+/// it will not produce any diagnostics if no conversion is available,
+/// but will instead return an implicit conversion sequence of kind
+/// "BadConversion".
+ImplicitConversionSequence
+Sema::TryCopyInitialization(Expr* From, QualType ToType)
+{
+ ImplicitConversionSequence ICS;
+
+ QualType FromType = From->getType();
+
+ // Standard conversions (C++ 4)
+ ICS.ConversionKind = ImplicitConversionSequence::StandardConversion;
+ ICS.Standard.Deprecated = false;
+ ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr();
+
+ // The first conversion can be an lvalue-to-rvalue conversion,
+ // array-to-pointer conversion, or function-to-pointer conversion
+ // (C++ 4p1).
+
+ // Lvalue-to-rvalue conversion (C++ 4.1):
+ // An lvalue (3.10) of a non-function, non-array type T can be
+ // converted to an rvalue.
+ Expr::isLvalueResult argIsLvalue = From->isLvalue(Context);
+ if (argIsLvalue == Expr::LV_Valid &&
+ !FromType->isFunctionType() && !FromType->isArrayType()) {
+ ICS.Standard.First = ICK_Lvalue_To_Rvalue;
+
+ // If T is a non-class type, the type of the rvalue is the
+ // cv-unqualified version of T. Otherwise, the type of the rvalue
+ // is T (C++ 4.1p1).
+ if (!FromType->isRecordType())
+ FromType = FromType.getUnqualifiedType();
+ }
+ // Array-to-pointer conversion (C++ 4.2)
+ else if (FromType->isArrayType()) {
+ ICS.Standard.First = ICK_Array_To_Pointer;
+
+ // An lvalue or rvalue of type "array of N T" or "array of unknown
+ // bound of T" can be converted to an rvalue of type "pointer to
+ // T" (C++ 4.2p1).
+ FromType = Context.getArrayDecayedType(FromType);
+
+ if (IsStringLiteralToNonConstPointerConversion(From, ToType)) {
+ // This conversion is deprecated. (C++ D.4).
+ ICS.Standard.Deprecated = true;
+
+ // For the purpose of ranking in overload resolution
+ // (13.3.3.1.1), this conversion is considered an
+ // array-to-pointer conversion followed by a qualification
+ // conversion (4.4). (C++ 4.2p2)
+ ICS.Standard.Second = ICK_Identity;
+ ICS.Standard.Third = ICK_Qualification;
+ ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr();
+ return ICS;
+ }
+ }
+ // Function-to-pointer conversion (C++ 4.3).
+ else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) {
+ ICS.Standard.First = ICK_Function_To_Pointer;
+
+ // An lvalue of function type T can be converted to an rvalue of
+ // type "pointer to T." The result is a pointer to the
+ // function. (C++ 4.3p1).
+ FromType = Context.getPointerType(FromType);
+
+ // FIXME: Deal with overloaded functions here (C++ 4.3p2).
+ }
+ // We don't require any conversions for the first step.
+ else {
+ ICS.Standard.First = ICK_Identity;
+ }
+
+ // The second conversion can be an integral promotion, floating
+ // point promotion, integral conversion, floating point conversion,
+ // floating-integral conversion, pointer conversion,
+ // pointer-to-member conversion, or boolean conversion (C++ 4p1).
+ if (Context.getCanonicalType(FromType).getUnqualifiedType() ==
+ Context.getCanonicalType(ToType).getUnqualifiedType()) {
+ // The unqualified versions of the types are the same: there's no
+ // conversion to do.
+ ICS.Standard.Second = ICK_Identity;
+ }
+ // Integral promotion (C++ 4.5).
+ else if (IsIntegralPromotion(From, FromType, ToType)) {
+ ICS.Standard.Second = ICK_Integral_Promotion;
+ FromType = ToType.getUnqualifiedType();
+ }
+ // Floating point promotion (C++ 4.6).
+ else if (IsFloatingPointPromotion(FromType, ToType)) {
+ ICS.Standard.Second = ICK_Floating_Promotion;
+ FromType = ToType.getUnqualifiedType();
+ }
+ // Integral conversions (C++ 4.7).
+ else if ((FromType->isIntegralType() || FromType->isEnumeralType()) &&
+ (ToType->isIntegralType() || ToType->isEnumeralType())) {
+ ICS.Standard.Second = ICK_Integral_Conversion;
+ FromType = ToType.getUnqualifiedType();
+ }
+ // Floating point conversions (C++ 4.8).
+ else if (FromType->isFloatingType() && ToType->isFloatingType()) {
+ ICS.Standard.Second = ICK_Floating_Conversion;
+ FromType = ToType.getUnqualifiedType();
+ }
+ // Floating-integral conversions (C++ 4.9).
+ else if ((FromType->isFloatingType() &&
+ ToType->isIntegralType() && !ToType->isBooleanType()) ||
+ ((FromType->isIntegralType() || FromType->isEnumeralType()) &&
+ ToType->isFloatingType())) {
+ ICS.Standard.Second = ICK_Floating_Integral;
+ FromType = ToType.getUnqualifiedType();
+ }
+ // Pointer conversions (C++ 4.10).
+ else if (IsPointerConversion(From, FromType, ToType, FromType))
+ ICS.Standard.Second = ICK_Pointer_Conversion;
+ // FIXME: Pointer to member conversions (4.11).
+ // Boolean conversions (C++ 4.12).
+ // FIXME: pointer-to-member type
+ else if (ToType->isBooleanType() &&
+ (FromType->isArithmeticType() ||
+ FromType->isEnumeralType() ||
+ FromType->isPointerType())) {
+ ICS.Standard.Second = ICK_Boolean_Conversion;
+ FromType = Context.BoolTy;
+ } else {
+ // No second conversion required.
+ ICS.Standard.Second = ICK_Identity;
+ }
+
+ // The third conversion can be a qualification conversion (C++ 4p1).
+ // FIXME: CheckPointerTypesForAssignment isn't the right way to
+ // determine whether we have a qualification conversion.
+ if (Context.getCanonicalType(FromType) != Context.getCanonicalType(ToType)
+ && CheckPointerTypesForAssignment(ToType, FromType) == Compatible) {
+ ICS.Standard.Third = ICK_Qualification;
+ FromType = ToType;
+ } else {
+ // No conversion required
+ ICS.Standard.Third = ICK_Identity;
+ }
+
+ // If we have not converted the argument type to the parameter type,
+ // this is a bad conversion sequence.
+ if (Context.getCanonicalType(FromType) != Context.getCanonicalType(ToType))
+ ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
+
+ ICS.Standard.ToTypePtr = FromType.getAsOpaquePtr();
+ return ICS;
+}
+
+/// IsIntegralPromotion - Determines whether the conversion from the
+/// expression From (whose potentially-adjusted type is FromType) to
+/// ToType is an integral promotion (C++ 4.5). If so, returns true and
+/// sets PromotedType to the promoted type.
+bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType)
+{
+ const BuiltinType *To = ToType->getAsBuiltinType();
+
+ // An rvalue of type char, signed char, unsigned char, short int, or
+ // unsigned short int can be converted to an rvalue of type int if
+ // int can represent all the values of the source type; otherwise,
+ // the source rvalue can be converted to an rvalue of type unsigned
+ // int (C++ 4.5p1).
+ if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && To) {
+ if (// We can promote any signed, promotable integer type to an int
+ (FromType->isSignedIntegerType() ||
+ // We can promote any unsigned integer type whose size is
+ // less than int to an int.
+ (!FromType->isSignedIntegerType() &&
+ Context.getTypeSize(FromType) < Context.getTypeSize(ToType))))
+ return To->getKind() == BuiltinType::Int;
+
+ return To->getKind() == BuiltinType::UInt;
+ }
+
+ // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2)
+ // can be converted to an rvalue of the first of the following types
+ // that can represent all the values of its underlying type: int,
+ // unsigned int, long, or unsigned long (C++ 4.5p2).
+ if ((FromType->isEnumeralType() || FromType->isWideCharType())
+ && ToType->isIntegerType()) {
+ // Determine whether the type we're converting from is signed or
+ // unsigned.
+ bool FromIsSigned;
+ uint64_t FromSize = Context.getTypeSize(FromType);
+ if (const EnumType *FromEnumType = FromType->getAsEnumType()) {
+ QualType UnderlyingType = FromEnumType->getDecl()->getIntegerType();
+ FromIsSigned = UnderlyingType->isSignedIntegerType();
+ } else {
+ // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now.
+ FromIsSigned = true;
+ }
+
+ // The types we'll try to promote to, in the appropriate
+ // order. Try each of these types.
+ QualType PromoteTypes[4] = {
+ Context.IntTy, Context.UnsignedIntTy,
+ Context.LongTy, Context.UnsignedLongTy
+ };
+ for (int Idx = 0; Idx < 0; ++Idx) {
+ uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
+ if (FromSize < ToSize ||
+ (FromSize == ToSize &&
+ FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
+ // We found the type that we can promote to. If this is the
+ // type we wanted, we have a promotion. Otherwise, no
+ // promotion.
+ return Context.getCanonicalType(FromType).getUnqualifiedType()
+ == Context.getCanonicalType(PromoteTypes[Idx]).getUnqualifiedType();
+ }
+ }
+ }
+
+ // An rvalue for an integral bit-field (9.6) can be converted to an
+ // rvalue of type int if int can represent all the values of the
+ // bit-field; otherwise, it can be converted to unsigned int if
+ // unsigned int can represent all the values of the bit-field. If
+ // the bit-field is larger yet, no integral promotion applies to
+ // it. If the bit-field has an enumerated type, it is treated as any
+ // other value of that type for promotion purposes (C++ 4.5p3).
+ if (MemberExpr *MemRef = dyn_cast<MemberExpr>(From)) {
+ using llvm::APSInt;
+ FieldDecl *MemberDecl = MemRef->getMemberDecl();
+ APSInt BitWidth;
+ if (MemberDecl->isBitField() &&
+ FromType->isIntegralType() && !FromType->isEnumeralType() &&
+ From->isIntegerConstantExpr(BitWidth, Context)) {
+ APSInt ToSize(Context.getTypeSize(ToType));
+
+ // Are we promoting to an int from a bitfield that fits in an int?
+ if (BitWidth < ToSize ||
+ (FromType->isSignedIntegerType() && BitWidth <= ToSize))
+ return To->getKind() == BuiltinType::Int;
+
+ // Are we promoting to an unsigned int from an unsigned bitfield
+ // that fits into an unsigned int?
+ if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize)
+ return To->getKind() == BuiltinType::UInt;
+
+ return false;
+ }
+ }
+
+ // An rvalue of type bool can be converted to an rvalue of type int,
+ // with false becoming zero and true becoming one (C++ 4.5p4).
+ if (FromType->isBooleanType() && To && To->getKind() == BuiltinType::Int)
+ return true;
+
+ return false;
+}
+
+/// IsFloatingPointPromotion - Determines whether the conversion from
+/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
+/// returns true and sets PromotedType to the promoted type.
+bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType)
+{
+ /// An rvalue of type float can be converted to an rvalue of type
+ /// double. (C++ 4.6p1).
+ if (const BuiltinType *FromBuiltin = FromType->getAsBuiltinType())
+ if (const BuiltinType *ToBuiltin = ToType->getAsBuiltinType())
+ if (FromBuiltin->getKind() == BuiltinType::Float &&
+ ToBuiltin->getKind() == BuiltinType::Double)
+ return true;
+
+ return false;
+}
+
+/// IsPointerConversion - Determines whether the conversion of the
+/// expression From, which has the (possibly adjusted) type FromType,
+/// can be converted to the type ToType via a pointer conversion (C++
+/// 4.10). If so, returns true and places the converted type (that
+/// might differ from ToType in its cv-qualifiers at some level) into
+/// ConvertedType.
+bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
+ QualType& ConvertedType)
+{
+ const PointerType* ToTypePtr = ToType->getAsPointerType();
+ if (!ToTypePtr)
+ return false;
+
+ // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
+ if (From->isNullPointerConstant(Context)) {
+ ConvertedType = ToType;
+ return true;
+ }
+
+ // An rvalue of type "pointer to cv T," where T is an object type,
+ // can be converted to an rvalue of type "pointer to cv void" (C++
+ // 4.10p2).
+ if (FromType->isPointerType() &&
+ FromType->getAsPointerType()->getPointeeType()->isObjectType() &&
+ ToTypePtr->getPointeeType()->isVoidType()) {
+ // We need to produce a pointer to cv void, where cv is the same
+ // set of cv-qualifiers as we had on the incoming pointee type.
+ QualType toPointee = ToTypePtr->getPointeeType();
+ unsigned Quals = Context.getCanonicalType(FromType)->getAsPointerType()
+ ->getPointeeType().getCVRQualifiers();
+
+ if (Context.getCanonicalType(ToTypePtr->getPointeeType()).getCVRQualifiers()
+ == Quals) {
+ // ToType is exactly the type we want. Use it.
+ ConvertedType = ToType;
+ } else {
+ // Build a new type with the right qualifiers.
+ ConvertedType
+ = Context.getPointerType(Context.VoidTy.getQualifiedType(Quals));
+ }
+ return true;
+ }
+
+ // FIXME: An rvalue of type "pointer to cv D," where D is a class
+ // type, can be converted to an rvalue of type "pointer to cv B,"
+ // where B is a base class (clause 10) of D (C++ 4.10p3).
+ return false;
+}
+
+/// CompareImplicitConversionSequences - Compare two implicit
+/// conversion sequences to determine whether one is better than the
+/// other or if they are indistinguishable (C++ 13.3.3.2).
+ImplicitConversionSequence::CompareKind
+Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1,
+ const ImplicitConversionSequence& ICS2)
+{
+ // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
+ // conversion sequences (as defined in 13.3.3.1)
+ // -- a standard conversion sequence (13.3.3.1.1) is a better
+ // conversion sequence than a user-defined conversion sequence or
+ // an ellipsis conversion sequence, and
+ // -- a user-defined conversion sequence (13.3.3.1.2) is a better
+ // conversion sequence than an ellipsis conversion sequence
+ // (13.3.3.1.3).
+ //
+ if (ICS1.ConversionKind < ICS2.ConversionKind)
+ return ImplicitConversionSequence::Better;
+ else if (ICS2.ConversionKind < ICS1.ConversionKind)
+ return ImplicitConversionSequence::Worse;
+
+ // Two implicit conversion sequences of the same form are
+ // indistinguishable conversion sequences unless one of the
+ // following rules apply: (C++ 13.3.3.2p3):
+ if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion)
+ return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard);
+ else if (ICS1.ConversionKind ==
+ ImplicitConversionSequence::UserDefinedConversion) {
+ // User-defined conversion sequence U1 is a better conversion
+ // sequence than another user-defined conversion sequence U2 if
+ // they contain the same user-defined conversion function or
+ // constructor and if the second standard conversion sequence of
+ // U1 is better than the second standard conversion sequence of
+ // U2 (C++ 13.3.3.2p3).
+ if (ICS1.UserDefined.ConversionFunction ==
+ ICS2.UserDefined.ConversionFunction)
+ return CompareStandardConversionSequences(ICS1.UserDefined.After,
+ ICS2.UserDefined.After);
+ }
+
+ return ImplicitConversionSequence::Indistinguishable;
+}
+
+/// CompareStandardConversionSequences - Compare two standard
+/// conversion sequences to determine whether one is better than the
+/// other or if they are indistinguishable (C++ 13.3.3.2p3).
+ImplicitConversionSequence::CompareKind
+Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1,
+ const StandardConversionSequence& SCS2)
+{
+ // Standard conversion sequence S1 is a better conversion sequence
+ // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
+
+ // -- S1 is a proper subsequence of S2 (comparing the conversion
+ // sequences in the canonical form defined by 13.3.3.1.1,
+ // excluding any Lvalue Transformation; the identity conversion
+ // sequence is considered to be a subsequence of any
+ // non-identity conversion sequence) or, if not that,
+ if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third)
+ // Neither is a proper subsequence of the other. Do nothing.
+ ;
+ else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) ||
+ (SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) ||
+ (SCS1.Second == ICK_Identity &&
+ SCS1.Third == ICK_Identity))
+ // SCS1 is a proper subsequence of SCS2.
+ return ImplicitConversionSequence::Better;
+ else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) ||
+ (SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) ||
+ (SCS2.Second == ICK_Identity &&
+ SCS2.Third == ICK_Identity))
+ // SCS2 is a proper subsequence of SCS1.
+ return ImplicitConversionSequence::Worse;
+
+ // -- the rank of S1 is better than the rank of S2 (by the rules
+ // defined below), or, if not that,
+ ImplicitConversionRank Rank1 = SCS1.getRank();
+ ImplicitConversionRank Rank2 = SCS2.getRank();
+ if (Rank1 < Rank2)
+ return ImplicitConversionSequence::Better;
+ else if (Rank2 < Rank1)
+ return ImplicitConversionSequence::Worse;
+ else {
+ // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
+ // are indistinguishable unless one of the following rules
+ // applies:
+
+ // A conversion that is not a conversion of a pointer, or
+ // pointer to member, to bool is better than another conversion
+ // that is such a conversion.
+ if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
+ return SCS2.isPointerConversionToBool()
+ ? ImplicitConversionSequence::Better
+ : ImplicitConversionSequence::Worse;
+
+ // FIXME: The other bullets in (C++ 13.3.3.2p4) require support
+ // for derived classes.
+ }
+
+ // FIXME: Handle comparison by qualifications.
+ // FIXME: Handle comparison of reference bindings.
+ return ImplicitConversionSequence::Indistinguishable;
+}
+
+/// AddOverloadCandidate - Adds the given function to the set of
+/// candidate functions, using the given function call arguments.
+void
+Sema::AddOverloadCandidate(FunctionDecl *Function,
+ Expr **Args, unsigned NumArgs,
+ OverloadCandidateSet& CandidateSet)
+{
+ const FunctionTypeProto* Proto
+ = dyn_cast<FunctionTypeProto>(Function->getType()->getAsFunctionType());
+ assert(Proto && "Functions without a prototype cannot be overloaded");
+
+ // Add this candidate
+ CandidateSet.push_back(OverloadCandidate());
+ OverloadCandidate& Candidate = CandidateSet.back();
+ Candidate.Function = Function;
+
+ unsigned NumArgsInProto = Proto->getNumArgs();
+
+ // (C++ 13.3.2p2): A candidate function having fewer than m
+ // parameters is viable only if it has an ellipsis in its parameter
+ // list (8.3.5).
+ if (NumArgs > NumArgsInProto && !Proto->isVariadic()) {
+ Candidate.Viable = false;
+ return;
+ }
+
+ // (C++ 13.3.2p2): A candidate function having more than m parameters
+ // is viable only if the (m+1)st parameter has a default argument
+ // (8.3.6). For the purposes of overload resolution, the
+ // parameter list is truncated on the right, so that there are
+ // exactly m parameters.
+ unsigned MinRequiredArgs = Function->getMinRequiredArguments();
+ if (NumArgs < MinRequiredArgs) {
+ // Not enough arguments.
+ Candidate.Viable = false;
+ return;
+ }
+
+ // Determine the implicit conversion sequences for each of the
+ // arguments.
+ Candidate.Viable = true;
+ Candidate.Conversions.resize(NumArgs);
+ for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) {
+ if (ArgIdx < NumArgsInProto) {
+ // (C++ 13.3.2p3): for F to be a viable function, there shall
+ // exist for each argument an implicit conversion sequence
+ // (13.3.3.1) that converts that argument to the corresponding
+ // parameter of F.
+ QualType ParamType = Proto->getArgType(ArgIdx);
+ Candidate.Conversions[ArgIdx]
+ = TryCopyInitialization(Args[ArgIdx], ParamType);
+ if (Candidate.Conversions[ArgIdx].ConversionKind
+ == ImplicitConversionSequence::BadConversion)
+ Candidate.Viable = false;
+ } else {
+ // (C++ 13.3.2p2): For the purposes of overload resolution, any
+ // argument for which there is no corresponding parameter is
+ // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
+ Candidate.Conversions[ArgIdx].ConversionKind
+ = ImplicitConversionSequence::EllipsisConversion;
+ }
+ }
+}
+
+/// AddOverloadCandidates - Add all of the function overloads in Ovl
+/// to the candidate set.
+void
+Sema::AddOverloadCandidates(OverloadedFunctionDecl *Ovl,
+ Expr **Args, unsigned NumArgs,
+ OverloadCandidateSet& CandidateSet)
+{
+ for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin();
+ Func != Ovl->function_end(); ++Func)
+ AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet);
+}
+
+/// isBetterOverloadCandidate - Determines whether the first overload
+/// candidate is a better candidate than the second (C++ 13.3.3p1).
+bool
+Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1,
+ const OverloadCandidate& Cand2)
+{
+ // Define viable functions to be better candidates than non-viable
+ // functions.
+ if (!Cand2.Viable)
+ return Cand1.Viable;
+ else if (!Cand1.Viable)
+ return false;
+
+ // FIXME: Deal with the implicit object parameter for static member
+ // functions. (C++ 13.3.3p1).
+
+ // (C++ 13.3.3p1): a viable function F1 is defined to be a better
+ // function than another viable function F2 if for all arguments i,
+ // ICSi(F1) is not a worse conversion sequence than ICSi(F2), and
+ // then...
+ unsigned NumArgs = Cand1.Conversions.size();
+ assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch");
+ bool HasBetterConversion = false;
+ for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) {
+ switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx],
+ Cand2.Conversions[ArgIdx])) {
+ case ImplicitConversionSequence::Better:
+ // Cand1 has a better conversion sequence.
+ HasBetterConversion = true;
+ break;
+
+ case ImplicitConversionSequence::Worse:
+ // Cand1 can't be better than Cand2.
+ return false;
+
+ case ImplicitConversionSequence::Indistinguishable:
+ // Do nothing.
+ break;
+ }
+ }
+
+ if (HasBetterConversion)
+ return true;
+
+ // FIXME: Several other bullets in (C++ 13.3.3p1) need to be implemented.
+
+ return false;
+}
+
+/// BestViableFunction - Computes the best viable function (C++ 13.3.3)
+/// within an overload candidate set. If overloading is successful,
+/// the result will be OR_Success and Best will be set to point to the
+/// best viable function within the candidate set. Otherwise, one of
+/// several kinds of errors will be returned; see
+/// Sema::OverloadingResult.
+Sema::OverloadingResult
+Sema::BestViableFunction(OverloadCandidateSet& CandidateSet,
+ OverloadCandidateSet::iterator& Best)
+{
+ // Find the best viable function.
+ Best = CandidateSet.end();
+ for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
+ Cand != CandidateSet.end(); ++Cand) {
+ if (Cand->Viable) {
+ if (Best == CandidateSet.end() || isBetterOverloadCandidate(*Cand, *Best))
+ Best = Cand;
+ }
+ }
+
+ // If we didn't find any viable functions, abort.
+ if (Best == CandidateSet.end())
+ return OR_No_Viable_Function;
+
+ // Make sure that this function is better than every other viable
+ // function. If not, we have an ambiguity.
+ for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
+ Cand != CandidateSet.end(); ++Cand) {
+ if (Cand->Viable &&
+ Cand != Best &&
+ !isBetterOverloadCandidate(*Best, *Cand))
+ return OR_Ambiguous;
+ }
+
+ // Best is the best viable function.
+ return OR_Success;
+}
+
+/// PrintOverloadCandidates - When overload resolution fails, prints
+/// diagnostic messages containing the candidates in the candidate
+/// set. If OnlyViable is true, only viable candidates will be printed.
+void
+Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet,
+ bool OnlyViable)
+{
+ OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
+ LastCand = CandidateSet.end();
+ for (; Cand != LastCand; ++Cand) {
+ if (Cand->Viable ||!OnlyViable)
+ Diag(Cand->Function->getLocation(), diag::err_ovl_candidate);
+ }
+}
+
+} // end namespace clang