mirror of
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ad3f2fcf43
templates.
For example, this now type-checks (but does not instantiate the body
of deref<int>):
template<typename T> T& deref(T* t) { return *t; }
void test(int *ip) {
int &ir = deref(ip);
}
Specific changes/additions:
* Template argument deduction from a call to a function template.
* Instantiation of a function template specializations (just the
declarations) from the template arguments deduced from a call.
* FunctionTemplateDecls are stored directly in declaration contexts
and found via name lookup (all forms), rather than finding the
FunctionDecl and then realizing it is a template. This is
responsible for most of the churn, since some of the core
declaration matching and lookup code assumes that all functions are
FunctionDecls.
llvm-svn: 74213
1061 lines
40 KiB
C++
1061 lines
40 KiB
C++
//===------- SemaTemplateDeduction.cpp - Template Argument Deduction ------===/
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===/
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//
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// This file implements C++ template argument deduction.
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//
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//===----------------------------------------------------------------------===/
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#include "Sema.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/DeclTemplate.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/Parse/DeclSpec.h"
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#include "llvm/Support/Compiler.h"
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using namespace clang;
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static Sema::TemplateDeductionResult
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DeduceTemplateArguments(ASTContext &Context,
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TemplateParameterList *TemplateParams,
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const TemplateArgument &Param,
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const TemplateArgument &Arg,
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Sema::TemplateDeductionInfo &Info,
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llvm::SmallVectorImpl<TemplateArgument> &Deduced);
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/// \brief If the given expression is of a form that permits the deduction
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/// of a non-type template parameter, return the declaration of that
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/// non-type template parameter.
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static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) {
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if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
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E = IC->getSubExpr();
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if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
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return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
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return 0;
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}
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/// \brief Deduce the value of the given non-type template parameter
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/// from the given constant.
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static Sema::TemplateDeductionResult
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DeduceNonTypeTemplateArgument(ASTContext &Context,
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NonTypeTemplateParmDecl *NTTP,
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llvm::APSInt Value,
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Sema::TemplateDeductionInfo &Info,
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llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
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assert(NTTP->getDepth() == 0 &&
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"Cannot deduce non-type template argument with depth > 0");
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if (Deduced[NTTP->getIndex()].isNull()) {
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QualType T = NTTP->getType();
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// FIXME: Make sure we didn't overflow our data type!
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unsigned AllowedBits = Context.getTypeSize(T);
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if (Value.getBitWidth() != AllowedBits)
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Value.extOrTrunc(AllowedBits);
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Value.setIsSigned(T->isSignedIntegerType());
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Deduced[NTTP->getIndex()] = TemplateArgument(SourceLocation(), Value, T);
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return Sema::TDK_Success;
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}
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assert(Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Integral);
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// If the template argument was previously deduced to a negative value,
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// then our deduction fails.
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const llvm::APSInt *PrevValuePtr = Deduced[NTTP->getIndex()].getAsIntegral();
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if (PrevValuePtr->isNegative()) {
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Info.Param = NTTP;
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Info.FirstArg = Deduced[NTTP->getIndex()];
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Info.SecondArg = TemplateArgument(SourceLocation(), Value, NTTP->getType());
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return Sema::TDK_Inconsistent;
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}
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llvm::APSInt PrevValue = *PrevValuePtr;
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if (Value.getBitWidth() > PrevValue.getBitWidth())
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PrevValue.zext(Value.getBitWidth());
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else if (Value.getBitWidth() < PrevValue.getBitWidth())
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Value.zext(PrevValue.getBitWidth());
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if (Value != PrevValue) {
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Info.Param = NTTP;
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Info.FirstArg = Deduced[NTTP->getIndex()];
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Info.SecondArg = TemplateArgument(SourceLocation(), Value, NTTP->getType());
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return Sema::TDK_Inconsistent;
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}
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return Sema::TDK_Success;
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}
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/// \brief Deduce the value of the given non-type template parameter
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/// from the given type- or value-dependent expression.
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///
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/// \returns true if deduction succeeded, false otherwise.
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static Sema::TemplateDeductionResult
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DeduceNonTypeTemplateArgument(ASTContext &Context,
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NonTypeTemplateParmDecl *NTTP,
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Expr *Value,
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Sema::TemplateDeductionInfo &Info,
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llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
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assert(NTTP->getDepth() == 0 &&
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"Cannot deduce non-type template argument with depth > 0");
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assert((Value->isTypeDependent() || Value->isValueDependent()) &&
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"Expression template argument must be type- or value-dependent.");
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if (Deduced[NTTP->getIndex()].isNull()) {
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// FIXME: Clone the Value?
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Deduced[NTTP->getIndex()] = TemplateArgument(Value);
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return Sema::TDK_Success;
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}
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if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Integral) {
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// Okay, we deduced a constant in one case and a dependent expression
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// in another case. FIXME: Later, we will check that instantiating the
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// dependent expression gives us the constant value.
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return Sema::TDK_Success;
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}
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// FIXME: Compare the expressions for equality!
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return Sema::TDK_Success;
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}
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static Sema::TemplateDeductionResult
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DeduceTemplateArguments(ASTContext &Context,
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TemplateName Param,
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TemplateName Arg,
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Sema::TemplateDeductionInfo &Info,
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llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
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// FIXME: Implement template argument deduction for template
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// template parameters.
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// FIXME: this routine does not have enough information to produce
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// good diagnostics.
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TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
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TemplateDecl *ArgDecl = Arg.getAsTemplateDecl();
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if (!ParamDecl || !ArgDecl) {
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// FIXME: fill in Info.Param/Info.FirstArg
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return Sema::TDK_Inconsistent;
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}
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ParamDecl = cast<TemplateDecl>(Context.getCanonicalDecl(ParamDecl));
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ArgDecl = cast<TemplateDecl>(Context.getCanonicalDecl(ArgDecl));
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if (ParamDecl != ArgDecl) {
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// FIXME: fill in Info.Param/Info.FirstArg
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return Sema::TDK_Inconsistent;
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}
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return Sema::TDK_Success;
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}
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static Sema::TemplateDeductionResult
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DeduceTemplateArguments(ASTContext &Context,
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TemplateParameterList *TemplateParams,
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QualType ParamIn, QualType ArgIn,
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Sema::TemplateDeductionInfo &Info,
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llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
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// We only want to look at the canonical types, since typedefs and
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// sugar are not part of template argument deduction.
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QualType Param = Context.getCanonicalType(ParamIn);
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QualType Arg = Context.getCanonicalType(ArgIn);
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// If the parameter type is not dependent, just compare the types
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// directly.
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if (!Param->isDependentType()) {
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if (Param == Arg)
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return Sema::TDK_Success;
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Info.FirstArg = TemplateArgument(SourceLocation(), ParamIn);
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Info.SecondArg = TemplateArgument(SourceLocation(), ArgIn);
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return Sema::TDK_NonDeducedMismatch;
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}
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// C++ [temp.deduct.type]p9:
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// A template type argument T, a template template argument TT or a
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// template non-type argument i can be deduced if P and A have one of
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// the following forms:
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//
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// T
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// cv-list T
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if (const TemplateTypeParmType *TemplateTypeParm
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= Param->getAsTemplateTypeParmType()) {
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unsigned Index = TemplateTypeParm->getIndex();
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// The argument type can not be less qualified than the parameter
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// type.
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if (Param.isMoreQualifiedThan(Arg)) {
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Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
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Info.FirstArg = Deduced[Index];
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Info.SecondArg = TemplateArgument(SourceLocation(), Arg);
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return Sema::TDK_InconsistentQuals;
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}
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assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0");
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unsigned Quals = Arg.getCVRQualifiers() & ~Param.getCVRQualifiers();
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QualType DeducedType = Arg.getQualifiedType(Quals);
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if (Deduced[Index].isNull())
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Deduced[Index] = TemplateArgument(SourceLocation(), DeducedType);
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else {
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// C++ [temp.deduct.type]p2:
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// [...] If type deduction cannot be done for any P/A pair, or if for
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// any pair the deduction leads to more than one possible set of
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// deduced values, or if different pairs yield different deduced
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// values, or if any template argument remains neither deduced nor
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// explicitly specified, template argument deduction fails.
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if (Deduced[Index].getAsType() != DeducedType) {
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Info.Param
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= cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
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Info.FirstArg = Deduced[Index];
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Info.SecondArg = TemplateArgument(SourceLocation(), Arg);
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return Sema::TDK_Inconsistent;
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}
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}
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return Sema::TDK_Success;
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}
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// Set up the template argument deduction information for a failure.
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Info.FirstArg = TemplateArgument(SourceLocation(), ParamIn);
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Info.SecondArg = TemplateArgument(SourceLocation(), ArgIn);
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if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
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return Sema::TDK_NonDeducedMismatch;
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switch (Param->getTypeClass()) {
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// No deduction possible for these types
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case Type::Builtin:
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return Sema::TDK_NonDeducedMismatch;
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// T *
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case Type::Pointer: {
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const PointerType *PointerArg = Arg->getAsPointerType();
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if (!PointerArg)
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return Sema::TDK_NonDeducedMismatch;
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return DeduceTemplateArguments(Context, TemplateParams,
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cast<PointerType>(Param)->getPointeeType(),
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PointerArg->getPointeeType(),
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Info, Deduced);
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}
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// T &
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case Type::LValueReference: {
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const LValueReferenceType *ReferenceArg = Arg->getAsLValueReferenceType();
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if (!ReferenceArg)
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return Sema::TDK_NonDeducedMismatch;
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return DeduceTemplateArguments(Context, TemplateParams,
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cast<LValueReferenceType>(Param)->getPointeeType(),
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ReferenceArg->getPointeeType(),
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Info, Deduced);
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}
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// T && [C++0x]
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case Type::RValueReference: {
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const RValueReferenceType *ReferenceArg = Arg->getAsRValueReferenceType();
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if (!ReferenceArg)
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return Sema::TDK_NonDeducedMismatch;
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return DeduceTemplateArguments(Context, TemplateParams,
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cast<RValueReferenceType>(Param)->getPointeeType(),
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ReferenceArg->getPointeeType(),
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Info, Deduced);
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}
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// T [] (implied, but not stated explicitly)
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case Type::IncompleteArray: {
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const IncompleteArrayType *IncompleteArrayArg =
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Context.getAsIncompleteArrayType(Arg);
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if (!IncompleteArrayArg)
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return Sema::TDK_NonDeducedMismatch;
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return DeduceTemplateArguments(Context, TemplateParams,
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Context.getAsIncompleteArrayType(Param)->getElementType(),
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IncompleteArrayArg->getElementType(),
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Info, Deduced);
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}
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// T [integer-constant]
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case Type::ConstantArray: {
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const ConstantArrayType *ConstantArrayArg =
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Context.getAsConstantArrayType(Arg);
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if (!ConstantArrayArg)
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return Sema::TDK_NonDeducedMismatch;
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const ConstantArrayType *ConstantArrayParm =
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Context.getAsConstantArrayType(Param);
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if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize())
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return Sema::TDK_NonDeducedMismatch;
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return DeduceTemplateArguments(Context, TemplateParams,
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ConstantArrayParm->getElementType(),
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ConstantArrayArg->getElementType(),
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Info, Deduced);
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}
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// type [i]
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case Type::DependentSizedArray: {
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const ArrayType *ArrayArg = dyn_cast<ArrayType>(Arg);
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if (!ArrayArg)
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return Sema::TDK_NonDeducedMismatch;
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// Check the element type of the arrays
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const DependentSizedArrayType *DependentArrayParm
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= cast<DependentSizedArrayType>(Param);
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if (Sema::TemplateDeductionResult Result
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= DeduceTemplateArguments(Context, TemplateParams,
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DependentArrayParm->getElementType(),
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ArrayArg->getElementType(),
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Info, Deduced))
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return Result;
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// Determine the array bound is something we can deduce.
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NonTypeTemplateParmDecl *NTTP
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= getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr());
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if (!NTTP)
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return Sema::TDK_Success;
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// We can perform template argument deduction for the given non-type
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// template parameter.
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assert(NTTP->getDepth() == 0 &&
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"Cannot deduce non-type template argument at depth > 0");
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if (const ConstantArrayType *ConstantArrayArg
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= dyn_cast<ConstantArrayType>(ArrayArg)) {
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llvm::APSInt Size(ConstantArrayArg->getSize());
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return DeduceNonTypeTemplateArgument(Context, NTTP, Size,
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Info, Deduced);
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}
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if (const DependentSizedArrayType *DependentArrayArg
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= dyn_cast<DependentSizedArrayType>(ArrayArg))
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return DeduceNonTypeTemplateArgument(Context, NTTP,
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DependentArrayArg->getSizeExpr(),
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Info, Deduced);
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// Incomplete type does not match a dependently-sized array type
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return Sema::TDK_NonDeducedMismatch;
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}
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// type(*)(T)
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// T(*)()
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// T(*)(T)
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case Type::FunctionProto: {
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const FunctionProtoType *FunctionProtoArg =
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dyn_cast<FunctionProtoType>(Arg);
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if (!FunctionProtoArg)
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return Sema::TDK_NonDeducedMismatch;
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const FunctionProtoType *FunctionProtoParam =
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cast<FunctionProtoType>(Param);
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if (FunctionProtoParam->getTypeQuals() !=
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FunctionProtoArg->getTypeQuals())
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return Sema::TDK_NonDeducedMismatch;
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if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs())
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return Sema::TDK_NonDeducedMismatch;
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if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
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return Sema::TDK_NonDeducedMismatch;
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// Check return types.
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if (Sema::TemplateDeductionResult Result
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= DeduceTemplateArguments(Context, TemplateParams,
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FunctionProtoParam->getResultType(),
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FunctionProtoArg->getResultType(),
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Info, Deduced))
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return Result;
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for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) {
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// Check argument types.
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if (Sema::TemplateDeductionResult Result
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= DeduceTemplateArguments(Context, TemplateParams,
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FunctionProtoParam->getArgType(I),
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FunctionProtoArg->getArgType(I),
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Info, Deduced))
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return Result;
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}
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return Sema::TDK_Success;
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}
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// template-name<T> (wheretemplate-name refers to a class template)
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// template-name<i>
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// TT<T> (TODO)
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// TT<i> (TODO)
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// TT<> (TODO)
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case Type::TemplateSpecialization: {
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const TemplateSpecializationType *SpecParam
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= cast<TemplateSpecializationType>(Param);
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// Check whether the template argument is a dependent template-id.
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// FIXME: This is untested code; it can be tested when we implement
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// partial ordering of class template partial specializations.
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if (const TemplateSpecializationType *SpecArg
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= dyn_cast<TemplateSpecializationType>(Arg)) {
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// Perform template argument deduction for the template name.
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if (Sema::TemplateDeductionResult Result
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= DeduceTemplateArguments(Context,
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SpecParam->getTemplateName(),
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SpecArg->getTemplateName(),
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Info, Deduced))
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return Result;
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unsigned NumArgs = SpecParam->getNumArgs();
|
||
|
||
// FIXME: When one of the template-names refers to a
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// declaration with default template arguments, do we need to
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// fill in those default template arguments here? Most likely,
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// the answer is "yes", but I don't see any references. This
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// issue may be resolved elsewhere, because we may want to
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// instantiate default template arguments when
|
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if (SpecArg->getNumArgs() != NumArgs)
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return Sema::TDK_NonDeducedMismatch;
|
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|
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// Perform template argument deduction on each template
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// argument.
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for (unsigned I = 0; I != NumArgs; ++I)
|
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if (Sema::TemplateDeductionResult Result
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= DeduceTemplateArguments(Context, TemplateParams,
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SpecParam->getArg(I),
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SpecArg->getArg(I),
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Info, Deduced))
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return Result;
|
||
|
||
return Sema::TDK_Success;
|
||
}
|
||
|
||
// If the argument type is a class template specialization, we
|
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// perform template argument deduction using its template
|
||
// arguments.
|
||
const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
|
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if (!RecordArg)
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
ClassTemplateSpecializationDecl *SpecArg
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||
= dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
|
||
if (!SpecArg)
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
// Perform template argument deduction for the template name.
|
||
if (Sema::TemplateDeductionResult Result
|
||
= DeduceTemplateArguments(Context,
|
||
SpecParam->getTemplateName(),
|
||
TemplateName(SpecArg->getSpecializedTemplate()),
|
||
Info, Deduced))
|
||
return Result;
|
||
|
||
// FIXME: Can the # of arguments in the parameter and the argument differ?
|
||
unsigned NumArgs = SpecParam->getNumArgs();
|
||
const TemplateArgumentList &ArgArgs = SpecArg->getTemplateArgs();
|
||
if (NumArgs != ArgArgs.size())
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
for (unsigned I = 0; I != NumArgs; ++I)
|
||
if (Sema::TemplateDeductionResult Result
|
||
= DeduceTemplateArguments(Context, TemplateParams,
|
||
SpecParam->getArg(I),
|
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ArgArgs.get(I),
|
||
Info, Deduced))
|
||
return Result;
|
||
|
||
return Sema::TDK_Success;
|
||
}
|
||
|
||
// T type::*
|
||
// T T::*
|
||
// T (type::*)()
|
||
// type (T::*)()
|
||
// type (type::*)(T)
|
||
// type (T::*)(T)
|
||
// T (type::*)(T)
|
||
// T (T::*)()
|
||
// T (T::*)(T)
|
||
case Type::MemberPointer: {
|
||
const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param);
|
||
const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
|
||
if (!MemPtrArg)
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
if (Sema::TemplateDeductionResult Result
|
||
= DeduceTemplateArguments(Context, TemplateParams,
|
||
MemPtrParam->getPointeeType(),
|
||
MemPtrArg->getPointeeType(),
|
||
Info, Deduced))
|
||
return Result;
|
||
|
||
return DeduceTemplateArguments(Context, TemplateParams,
|
||
QualType(MemPtrParam->getClass(), 0),
|
||
QualType(MemPtrArg->getClass(), 0),
|
||
Info, Deduced);
|
||
}
|
||
|
||
// (clang extension)
|
||
//
|
||
// type(^)(T)
|
||
// T(^)()
|
||
// T(^)(T)
|
||
case Type::BlockPointer: {
|
||
const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
|
||
const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);
|
||
|
||
if (!BlockPtrArg)
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
return DeduceTemplateArguments(Context, TemplateParams,
|
||
BlockPtrParam->getPointeeType(),
|
||
BlockPtrArg->getPointeeType(), Info,
|
||
Deduced);
|
||
}
|
||
|
||
case Type::TypeOfExpr:
|
||
case Type::TypeOf:
|
||
case Type::Typename:
|
||
// No template argument deduction for these types
|
||
return Sema::TDK_Success;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
// FIXME: Many more cases to go (to go).
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
}
|
||
|
||
static Sema::TemplateDeductionResult
|
||
DeduceTemplateArguments(ASTContext &Context,
|
||
TemplateParameterList *TemplateParams,
|
||
const TemplateArgument &Param,
|
||
const TemplateArgument &Arg,
|
||
Sema::TemplateDeductionInfo &Info,
|
||
llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
|
||
switch (Param.getKind()) {
|
||
case TemplateArgument::Null:
|
||
assert(false && "Null template argument in parameter list");
|
||
break;
|
||
|
||
case TemplateArgument::Type:
|
||
assert(Arg.getKind() == TemplateArgument::Type && "Type/value mismatch");
|
||
return DeduceTemplateArguments(Context, TemplateParams,
|
||
Param.getAsType(),
|
||
Arg.getAsType(), Info, Deduced);
|
||
|
||
case TemplateArgument::Declaration:
|
||
// FIXME: Implement this check
|
||
assert(false && "Unimplemented template argument deduction case");
|
||
Info.FirstArg = Param;
|
||
Info.SecondArg = Arg;
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
case TemplateArgument::Integral:
|
||
if (Arg.getKind() == TemplateArgument::Integral) {
|
||
// FIXME: Zero extension + sign checking here?
|
||
if (*Param.getAsIntegral() == *Arg.getAsIntegral())
|
||
return Sema::TDK_Success;
|
||
|
||
Info.FirstArg = Param;
|
||
Info.SecondArg = Arg;
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
}
|
||
|
||
if (Arg.getKind() == TemplateArgument::Expression) {
|
||
Info.FirstArg = Param;
|
||
Info.SecondArg = Arg;
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
}
|
||
|
||
assert(false && "Type/value mismatch");
|
||
Info.FirstArg = Param;
|
||
Info.SecondArg = Arg;
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
|
||
case TemplateArgument::Expression: {
|
||
if (NonTypeTemplateParmDecl *NTTP
|
||
= getDeducedParameterFromExpr(Param.getAsExpr())) {
|
||
if (Arg.getKind() == TemplateArgument::Integral)
|
||
// FIXME: Sign problems here
|
||
return DeduceNonTypeTemplateArgument(Context, NTTP,
|
||
*Arg.getAsIntegral(),
|
||
Info, Deduced);
|
||
if (Arg.getKind() == TemplateArgument::Expression)
|
||
return DeduceNonTypeTemplateArgument(Context, NTTP, Arg.getAsExpr(),
|
||
Info, Deduced);
|
||
|
||
assert(false && "Type/value mismatch");
|
||
Info.FirstArg = Param;
|
||
Info.SecondArg = Arg;
|
||
return Sema::TDK_NonDeducedMismatch;
|
||
}
|
||
|
||
// Can't deduce anything, but that's okay.
|
||
return Sema::TDK_Success;
|
||
}
|
||
case TemplateArgument::Pack:
|
||
assert(0 && "FIXME: Implement!");
|
||
break;
|
||
}
|
||
|
||
return Sema::TDK_Success;
|
||
}
|
||
|
||
static Sema::TemplateDeductionResult
|
||
DeduceTemplateArguments(ASTContext &Context,
|
||
TemplateParameterList *TemplateParams,
|
||
const TemplateArgumentList &ParamList,
|
||
const TemplateArgumentList &ArgList,
|
||
Sema::TemplateDeductionInfo &Info,
|
||
llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
|
||
assert(ParamList.size() == ArgList.size());
|
||
for (unsigned I = 0, N = ParamList.size(); I != N; ++I) {
|
||
if (Sema::TemplateDeductionResult Result
|
||
= DeduceTemplateArguments(Context, TemplateParams,
|
||
ParamList[I], ArgList[I],
|
||
Info, Deduced))
|
||
return Result;
|
||
}
|
||
return Sema::TDK_Success;
|
||
}
|
||
|
||
/// \brief Perform template argument deduction to determine whether
|
||
/// the given template arguments match the given class template
|
||
/// partial specialization per C++ [temp.class.spec.match].
|
||
Sema::TemplateDeductionResult
|
||
Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
|
||
const TemplateArgumentList &TemplateArgs,
|
||
TemplateDeductionInfo &Info) {
|
||
// C++ [temp.class.spec.match]p2:
|
||
// A partial specialization matches a given actual template
|
||
// argument list if the template arguments of the partial
|
||
// specialization can be deduced from the actual template argument
|
||
// list (14.8.2).
|
||
SFINAETrap Trap(*this);
|
||
llvm::SmallVector<TemplateArgument, 4> Deduced;
|
||
Deduced.resize(Partial->getTemplateParameters()->size());
|
||
if (TemplateDeductionResult Result
|
||
= ::DeduceTemplateArguments(Context,
|
||
Partial->getTemplateParameters(),
|
||
Partial->getTemplateArgs(),
|
||
TemplateArgs, Info, Deduced))
|
||
return Result;
|
||
|
||
InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial,
|
||
Deduced.data(), Deduced.size());
|
||
if (Inst)
|
||
return TDK_InstantiationDepth;
|
||
|
||
// C++ [temp.deduct.type]p2:
|
||
// [...] or if any template argument remains neither deduced nor
|
||
// explicitly specified, template argument deduction fails.
|
||
TemplateArgumentListBuilder Builder(Partial->getTemplateParameters(),
|
||
Deduced.size());
|
||
for (unsigned I = 0, N = Deduced.size(); I != N; ++I) {
|
||
if (Deduced[I].isNull()) {
|
||
Decl *Param
|
||
= const_cast<Decl *>(Partial->getTemplateParameters()->getParam(I));
|
||
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
|
||
Info.Param = TTP;
|
||
else if (NonTypeTemplateParmDecl *NTTP
|
||
= dyn_cast<NonTypeTemplateParmDecl>(Param))
|
||
Info.Param = NTTP;
|
||
else
|
||
Info.Param = cast<TemplateTemplateParmDecl>(Param);
|
||
return TDK_Incomplete;
|
||
}
|
||
|
||
Builder.Append(Deduced[I]);
|
||
}
|
||
|
||
// Form the template argument list from the deduced template arguments.
|
||
TemplateArgumentList *DeducedArgumentList
|
||
= new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true);
|
||
Info.reset(DeducedArgumentList);
|
||
|
||
// Substitute the deduced template arguments into the template
|
||
// arguments of the class template partial specialization, and
|
||
// verify that the instantiated template arguments are both valid
|
||
// and are equivalent to the template arguments originally provided
|
||
// to the class template.
|
||
ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate();
|
||
const TemplateArgumentList &PartialTemplateArgs = Partial->getTemplateArgs();
|
||
for (unsigned I = 0, N = PartialTemplateArgs.flat_size(); I != N; ++I) {
|
||
Decl *Param = const_cast<Decl *>(
|
||
ClassTemplate->getTemplateParameters()->getParam(I));
|
||
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
|
||
TemplateArgument InstArg = Instantiate(PartialTemplateArgs[I],
|
||
*DeducedArgumentList);
|
||
if (InstArg.getKind() != TemplateArgument::Type) {
|
||
Info.Param = TTP;
|
||
Info.FirstArg = PartialTemplateArgs[I];
|
||
return TDK_SubstitutionFailure;
|
||
}
|
||
|
||
if (Context.getCanonicalType(InstArg.getAsType())
|
||
!= Context.getCanonicalType(TemplateArgs[I].getAsType())) {
|
||
Info.Param = TTP;
|
||
Info.FirstArg = TemplateArgs[I];
|
||
Info.SecondArg = InstArg;
|
||
return TDK_NonDeducedMismatch;
|
||
}
|
||
|
||
continue;
|
||
}
|
||
|
||
// FIXME: Check template template arguments?
|
||
}
|
||
|
||
if (Trap.hasErrorOccurred())
|
||
return TDK_SubstitutionFailure;
|
||
|
||
return TDK_Success;
|
||
}
|
||
|
||
/// \brief Perform template argument deduction from a function call
|
||
/// (C++ [temp.deduct.call]).
|
||
///
|
||
/// \param FunctionTemplate the function template for which we are performing
|
||
/// template argument deduction.
|
||
///
|
||
/// \param Args the function call arguments
|
||
///
|
||
/// \param NumArgs the number of arguments in Args
|
||
///
|
||
/// \param Specialization if template argument deduction was successful,
|
||
/// this will be set to the function template specialization produced by
|
||
/// template argument deduction.
|
||
///
|
||
/// \param Info the argument will be updated to provide additional information
|
||
/// about template argument deduction.
|
||
///
|
||
/// \returns the result of template argument deduction.
|
||
///
|
||
/// FIXME: We will also need to pass in any explicitly-specified template
|
||
/// arguments.
|
||
Sema::TemplateDeductionResult
|
||
Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
|
||
Expr **Args, unsigned NumArgs,
|
||
FunctionDecl *&Specialization,
|
||
TemplateDeductionInfo &Info) {
|
||
FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
|
||
|
||
// C++ [temp.deduct.call]p1:
|
||
// Template argument deduction is done by comparing each function template
|
||
// parameter type (call it P) with the type of the corresponding argument
|
||
// of the call (call it A) as described below.
|
||
unsigned CheckArgs = NumArgs;
|
||
if (NumArgs < Function->getNumParams())
|
||
return TDK_TooFewArguments;
|
||
else if (NumArgs > Function->getNumParams()) {
|
||
const FunctionProtoType *Proto
|
||
= Function->getType()->getAsFunctionProtoType();
|
||
if (!Proto->isVariadic())
|
||
return TDK_TooManyArguments;
|
||
|
||
CheckArgs = Function->getNumParams();
|
||
}
|
||
|
||
SFINAETrap Trap(*this);
|
||
llvm::SmallVector<TemplateArgument, 4> Deduced;
|
||
Deduced.resize(FunctionTemplate->getTemplateParameters()->size());
|
||
TemplateParameterList *TemplateParams
|
||
= FunctionTemplate->getTemplateParameters();
|
||
for (unsigned I = 0; I != CheckArgs; ++I) {
|
||
QualType ParamType = Function->getParamDecl(I)->getType();
|
||
QualType ArgType = Args[I]->getType();
|
||
|
||
// C++ [temp.deduct.call]p2:
|
||
// If P is not a reference type:
|
||
QualType CanonParamType = Context.getCanonicalType(ParamType);
|
||
if (!isa<ReferenceType>(CanonParamType)) {
|
||
// - If A is an array type, the pointer type produced by the
|
||
// array-to-pointer standard conversion (4.2) is used in place of
|
||
// A for type deduction; otherwise,
|
||
if (ArgType->isArrayType())
|
||
ArgType = Context.getArrayDecayedType(ArgType);
|
||
// - If A is a function type, the pointer type produced by the
|
||
// function-to-pointer standard conversion (4.3) is used in place
|
||
// of A for type deduction; otherwise,
|
||
else if (ArgType->isFunctionType())
|
||
ArgType = Context.getPointerType(ArgType);
|
||
else {
|
||
// - If A is a cv-qualified type, the top level cv-qualifiers of A’s
|
||
// type are ignored for type deduction.
|
||
QualType CanonArgType = Context.getCanonicalType(ArgType);
|
||
if (CanonArgType.getCVRQualifiers())
|
||
ArgType = CanonArgType.getUnqualifiedType();
|
||
}
|
||
}
|
||
|
||
// C++0x [temp.deduct.call]p3:
|
||
// If P is a cv-qualified type, the top level cv-qualifiers of P’s type
|
||
// are ignored for type deduction.
|
||
if (CanonParamType.getCVRQualifiers())
|
||
ParamType = CanonParamType.getUnqualifiedType();
|
||
if (const ReferenceType *ParamRefType = ParamType->getAsReferenceType()) {
|
||
// [...] If P is a reference type, the type referred to by P is used
|
||
// for type deduction.
|
||
ParamType = ParamRefType->getPointeeType();
|
||
|
||
// [...] If P is of the form T&&, where T is a template parameter, and
|
||
// the argument is an lvalue, the type A& is used in place of A for
|
||
// type deduction.
|
||
if (isa<RValueReferenceType>(ParamRefType) &&
|
||
ParamRefType->getAsTemplateTypeParmType() &&
|
||
Args[I]->isLvalue(Context) == Expr::LV_Valid)
|
||
ArgType = Context.getLValueReferenceType(ArgType);
|
||
}
|
||
|
||
// C++0x [temp.deduct.call]p4:
|
||
// In general, the deduction process attempts to find template argument
|
||
// values that will make the deduced A identical to A (after the type A
|
||
// is transformed as described above). [...]
|
||
//
|
||
// FIXME: we'll pass down a flag to indicate when these cases may apply,
|
||
// and then deal with them in the code that deduces template
|
||
// arguments from a type.
|
||
if (TemplateDeductionResult Result
|
||
= ::DeduceTemplateArguments(Context, TemplateParams,
|
||
ParamType, ArgType, Info, Deduced))
|
||
return Result;
|
||
|
||
// FIXME: C++ [temp.deduct.call] paragraphs 6-9 deal with function
|
||
// pointer parameters.
|
||
}
|
||
|
||
InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(),
|
||
FunctionTemplate, Deduced.data(), Deduced.size());
|
||
if (Inst)
|
||
return TDK_InstantiationDepth;
|
||
|
||
// C++ [temp.deduct.type]p2:
|
||
// [...] or if any template argument remains neither deduced nor
|
||
// explicitly specified, template argument deduction fails.
|
||
TemplateArgumentListBuilder Builder(TemplateParams, Deduced.size());
|
||
for (unsigned I = 0, N = Deduced.size(); I != N; ++I) {
|
||
if (Deduced[I].isNull()) {
|
||
Decl *Param
|
||
= const_cast<Decl *>(TemplateParams->getParam(I));
|
||
if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
|
||
Info.Param = TTP;
|
||
else if (NonTypeTemplateParmDecl *NTTP
|
||
= dyn_cast<NonTypeTemplateParmDecl>(Param))
|
||
Info.Param = NTTP;
|
||
else
|
||
Info.Param = cast<TemplateTemplateParmDecl>(Param);
|
||
return TDK_Incomplete;
|
||
}
|
||
|
||
Builder.Append(Deduced[I]);
|
||
}
|
||
|
||
// Form the template argument list from the deduced template arguments.
|
||
TemplateArgumentList *DeducedArgumentList
|
||
= new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true);
|
||
Info.reset(DeducedArgumentList);
|
||
|
||
// Substitute the deduced template arguments into the function template
|
||
// declaration to produce the function template specialization.
|
||
Specialization = cast_or_null<FunctionDecl>(
|
||
InstantiateDecl(FunctionTemplate->getTemplatedDecl(),
|
||
FunctionTemplate->getDeclContext(),
|
||
*DeducedArgumentList));
|
||
|
||
if (!Specialization || Trap.hasErrorOccurred())
|
||
return TDK_SubstitutionFailure;
|
||
|
||
return TDK_Success;
|
||
}
|
||
|
||
static void
|
||
MarkDeducedTemplateParameters(Sema &SemaRef,
|
||
const TemplateArgument &TemplateArg,
|
||
llvm::SmallVectorImpl<bool> &Deduced);
|
||
|
||
/// \brief Mark the template arguments that are deduced by the given
|
||
/// expression.
|
||
static void
|
||
MarkDeducedTemplateParameters(const Expr *E,
|
||
llvm::SmallVectorImpl<bool> &Deduced) {
|
||
const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
|
||
if (!E)
|
||
return;
|
||
|
||
const NonTypeTemplateParmDecl *NTTP
|
||
= dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
|
||
if (!NTTP)
|
||
return;
|
||
|
||
Deduced[NTTP->getIndex()] = true;
|
||
}
|
||
|
||
/// \brief Mark the template parameters that are deduced by the given
|
||
/// type.
|
||
static void
|
||
MarkDeducedTemplateParameters(Sema &SemaRef, QualType T,
|
||
llvm::SmallVectorImpl<bool> &Deduced) {
|
||
// Non-dependent types have nothing deducible
|
||
if (!T->isDependentType())
|
||
return;
|
||
|
||
T = SemaRef.Context.getCanonicalType(T);
|
||
switch (T->getTypeClass()) {
|
||
case Type::ExtQual:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
QualType(cast<ExtQualType>(T)->getBaseType(), 0),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::Pointer:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
cast<PointerType>(T)->getPointeeType(),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::BlockPointer:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
cast<BlockPointerType>(T)->getPointeeType(),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::LValueReference:
|
||
case Type::RValueReference:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
cast<ReferenceType>(T)->getPointeeType(),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::MemberPointer: {
|
||
const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr());
|
||
MarkDeducedTemplateParameters(SemaRef, MemPtr->getPointeeType(), Deduced);
|
||
MarkDeducedTemplateParameters(SemaRef, QualType(MemPtr->getClass(), 0),
|
||
Deduced);
|
||
break;
|
||
}
|
||
|
||
case Type::DependentSizedArray:
|
||
MarkDeducedTemplateParameters(cast<DependentSizedArrayType>(T)->getSizeExpr(),
|
||
Deduced);
|
||
// Fall through to check the element type
|
||
|
||
case Type::ConstantArray:
|
||
case Type::IncompleteArray:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
cast<ArrayType>(T)->getElementType(),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::Vector:
|
||
case Type::ExtVector:
|
||
MarkDeducedTemplateParameters(SemaRef,
|
||
cast<VectorType>(T)->getElementType(),
|
||
Deduced);
|
||
break;
|
||
|
||
case Type::DependentSizedExtVector: {
|
||
const DependentSizedExtVectorType *VecType
|
||
= cast<DependentSizedExtVectorType>(T);
|
||
MarkDeducedTemplateParameters(SemaRef, VecType->getElementType(), Deduced);
|
||
MarkDeducedTemplateParameters(VecType->getSizeExpr(), Deduced);
|
||
break;
|
||
}
|
||
|
||
case Type::FunctionProto: {
|
||
const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
|
||
MarkDeducedTemplateParameters(SemaRef, Proto->getResultType(), Deduced);
|
||
for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I)
|
||
MarkDeducedTemplateParameters(SemaRef, Proto->getArgType(I), Deduced);
|
||
break;
|
||
}
|
||
|
||
case Type::TemplateTypeParm:
|
||
Deduced[cast<TemplateTypeParmType>(T)->getIndex()] = true;
|
||
break;
|
||
|
||
case Type::TemplateSpecialization: {
|
||
const TemplateSpecializationType *Spec
|
||
= cast<TemplateSpecializationType>(T);
|
||
if (TemplateDecl *Template = Spec->getTemplateName().getAsTemplateDecl())
|
||
if (TemplateTemplateParmDecl *TTP
|
||
= dyn_cast<TemplateTemplateParmDecl>(Template))
|
||
Deduced[TTP->getIndex()] = true;
|
||
|
||
for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
|
||
MarkDeducedTemplateParameters(SemaRef, Spec->getArg(I), Deduced);
|
||
|
||
break;
|
||
}
|
||
|
||
// None of these types have any deducible parts.
|
||
case Type::Builtin:
|
||
case Type::FixedWidthInt:
|
||
case Type::Complex:
|
||
case Type::VariableArray:
|
||
case Type::FunctionNoProto:
|
||
case Type::Record:
|
||
case Type::Enum:
|
||
case Type::Typename:
|
||
case Type::ObjCInterface:
|
||
case Type::ObjCQualifiedInterface:
|
||
case Type::ObjCObjectPointer:
|
||
#define TYPE(Class, Base)
|
||
#define ABSTRACT_TYPE(Class, Base)
|
||
#define DEPENDENT_TYPE(Class, Base)
|
||
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
|
||
#include "clang/AST/TypeNodes.def"
|
||
break;
|
||
}
|
||
}
|
||
|
||
/// \brief Mark the template parameters that are deduced by this
|
||
/// template argument.
|
||
static void
|
||
MarkDeducedTemplateParameters(Sema &SemaRef,
|
||
const TemplateArgument &TemplateArg,
|
||
llvm::SmallVectorImpl<bool> &Deduced) {
|
||
switch (TemplateArg.getKind()) {
|
||
case TemplateArgument::Null:
|
||
case TemplateArgument::Integral:
|
||
break;
|
||
|
||
case TemplateArgument::Type:
|
||
MarkDeducedTemplateParameters(SemaRef, TemplateArg.getAsType(), Deduced);
|
||
break;
|
||
|
||
case TemplateArgument::Declaration:
|
||
if (TemplateTemplateParmDecl *TTP
|
||
= dyn_cast<TemplateTemplateParmDecl>(TemplateArg.getAsDecl()))
|
||
Deduced[TTP->getIndex()] = true;
|
||
break;
|
||
|
||
case TemplateArgument::Expression:
|
||
MarkDeducedTemplateParameters(TemplateArg.getAsExpr(), Deduced);
|
||
break;
|
||
case TemplateArgument::Pack:
|
||
assert(0 && "FIXME: Implement!");
|
||
break;
|
||
}
|
||
}
|
||
|
||
/// \brief Mark the template parameters can be deduced by the given
|
||
/// template argument list.
|
||
///
|
||
/// \param TemplateArgs the template argument list from which template
|
||
/// parameters will be deduced.
|
||
///
|
||
/// \param Deduced a bit vector whose elements will be set to \c true
|
||
/// to indicate when the corresponding template parameter will be
|
||
/// deduced.
|
||
void
|
||
Sema::MarkDeducedTemplateParameters(const TemplateArgumentList &TemplateArgs,
|
||
llvm::SmallVectorImpl<bool> &Deduced) {
|
||
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
|
||
::MarkDeducedTemplateParameters(*this, TemplateArgs[I], Deduced);
|
||
}
|