[cfe-commits] r72909 - in /cfe/trunk: include/clang/AST/DeclTemplate.h lib/Sema/Sema.h lib/Sema/SemaTemplateDeduction.cpp lib/Sema/SemaTemplateInstantiate.cpp lib/Sema/SemaTemplateInstantiateExpr.cpp test/SemaTemplate/ackermann.cpp test/SemaTemplate/temp_class_spec.cpp
Douglas Gregor
dgregor at apple.com
Thu Jun 4 17:53:50 PDT 2009
Author: dgregor
Date: Thu Jun 4 19:53:49 2009
New Revision: 72909
URL: http://llvm.org/viewvc/llvm-project?rev=72909&view=rev
Log:
Several improvements to template argument deduction:
- Once we have deduced template arguments for a class template partial
specialization, we use exactly those template arguments for instantiating
the definition of the class template partial specialization.
- Added template argument deduction for non-type template parameters.
- Added template argument deduction for dependently-sized array types.
With these changes, we can now implement, e.g., the remove_reference
type trait. Also, Daniel's Ackermann template metaprogram now compiles
properly.
Added:
cfe/trunk/test/SemaTemplate/ackermann.cpp
Modified:
cfe/trunk/include/clang/AST/DeclTemplate.h
cfe/trunk/lib/Sema/Sema.h
cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
cfe/trunk/lib/Sema/SemaTemplateInstantiateExpr.cpp
cfe/trunk/test/SemaTemplate/temp_class_spec.cpp
Modified: cfe/trunk/include/clang/AST/DeclTemplate.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclTemplate.h?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclTemplate.h (original)
+++ cfe/trunk/include/clang/AST/DeclTemplate.h Thu Jun 4 19:53:49 2009
@@ -203,6 +203,9 @@
/// Get the position of the template parameter within its parameter list.
unsigned getPosition() const { return Position; }
+
+ /// Get the index of the template parameter within its parameter list.
+ unsigned getIndex() const { return Position; }
};
/// TemplateTypeParmDecl - Declaration of a template type parameter,
@@ -299,7 +302,8 @@
using TemplateParmPosition::getDepth;
using TemplateParmPosition::getPosition;
-
+ using TemplateParmPosition::getIndex;
+
/// \brief Determine whether this template parameter has a default
/// argument.
bool hasDefaultArgument() const { return DefaultArgument; }
@@ -350,7 +354,8 @@
using TemplateParmPosition::getDepth;
using TemplateParmPosition::getPosition;
-
+ using TemplateParmPosition::getIndex;
+
/// \brief Determine whether this template parameter has a default
/// argument.
bool hasDefaultArgument() const { return DefaultArgument; }
@@ -523,6 +528,12 @@
return QualType::getFromOpaquePtr(Integer.Type);
}
+ void setIntegralType(QualType T) {
+ assert(Kind == Integral &&
+ "Cannot set the integral type of a non-integral template argument");
+ Integer.Type = T.getAsOpaquePtr();
+ };
+
/// \brief Retrieve the template argument as an expression.
Expr *getAsExpr() const {
if (Kind != Expression)
Modified: cfe/trunk/lib/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.h?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/Sema.h (original)
+++ cfe/trunk/lib/Sema/Sema.h Thu Jun 4 19:53:49 2009
@@ -2019,8 +2019,9 @@
const IdentifierInfo &II,
SourceRange Range);
- bool DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
- const TemplateArgumentList &TemplateArgs);
+ TemplateArgumentList *
+ DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
+ const TemplateArgumentList &TemplateArgs);
//===--------------------------------------------------------------------===//
// C++ Template Instantiation
@@ -2227,7 +2228,7 @@
QualType InstantiateType(QualType T, const TemplateArgumentList &TemplateArgs,
SourceLocation Loc, DeclarationName Entity);
-
+
OwningExprResult InstantiateExpr(Expr *E,
const TemplateArgumentList &TemplateArgs);
Modified: cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateDeduction.cpp Thu Jun 4 19:53:49 2009
@@ -20,6 +20,86 @@
#include "llvm/Support/Compiler.h"
using namespace clang;
+/// \brief If the given expression is of a form that permits the deduction
+/// of a non-type template parameter, return the declaration of that
+/// non-type template parameter.
+static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) {
+ if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
+ E = IC->getSubExpr();
+
+ if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+ return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
+
+ return 0;
+}
+
+/// \brief Deduce the value of the given non-type template parameter
+/// from the given constant.
+///
+/// \returns true if deduction succeeded, false otherwise.
+static bool DeduceNonTypeTemplateArgument(ASTContext &Context,
+ NonTypeTemplateParmDecl *NTTP,
+ llvm::APInt Value,
+ llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
+ assert(NTTP->getDepth() == 0 &&
+ "Cannot deduce non-type template argument with depth > 0");
+
+ if (Deduced[NTTP->getIndex()].isNull()) {
+ Deduced[NTTP->getIndex()] = TemplateArgument(SourceLocation(),
+ llvm::APSInt(Value),
+ NTTP->getType());
+ return true;
+ }
+
+ if (Deduced[NTTP->getIndex()].getKind() != TemplateArgument::Integral)
+ return false;
+
+ // If the template argument was previously deduced to a negative value,
+ // then our deduction fails.
+ const llvm::APSInt *PrevValuePtr = Deduced[NTTP->getIndex()].getAsIntegral();
+ assert(PrevValuePtr && "Not an integral template argument?");
+ if (PrevValuePtr->isSigned() && PrevValuePtr->isNegative())
+ return false;
+
+ llvm::APInt PrevValue = *PrevValuePtr;
+ if (Value.getBitWidth() > PrevValue.getBitWidth())
+ PrevValue.zext(Value.getBitWidth());
+ else if (Value.getBitWidth() < PrevValue.getBitWidth())
+ Value.zext(PrevValue.getBitWidth());
+ return Value == PrevValue;
+}
+
+/// \brief Deduce the value of the given non-type template parameter
+/// from the given type- or value-dependent expression.
+///
+/// \returns true if deduction succeeded, false otherwise.
+
+static bool DeduceNonTypeTemplateArgument(ASTContext &Context,
+ NonTypeTemplateParmDecl *NTTP,
+ Expr *Value,
+ llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
+ assert(NTTP->getDepth() == 0 &&
+ "Cannot deduce non-type template argument with depth > 0");
+ assert((Value->isTypeDependent() || Value->isValueDependent()) &&
+ "Expression template argument must be type- or value-dependent.");
+
+ if (Deduced[NTTP->getIndex()].isNull()) {
+ // FIXME: Clone the Value?
+ Deduced[NTTP->getIndex()] = TemplateArgument(Value);
+ return true;
+ }
+
+ if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Integral) {
+ // Okay, we deduced a constant in one case and a dependent expression
+ // in another case. FIXME: Later, we will check that instantiating the
+ // dependent expression gives us the constant value.
+ return true;
+ }
+
+ // FIXME: Compare the expressions for equality!
+ return true;
+}
+
static bool DeduceTemplateArguments(ASTContext &Context, QualType Param,
QualType Arg,
llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
@@ -33,8 +113,14 @@
if (!Param->isDependentType())
return Param == Arg;
- // FIXME: Use a visitor or switch to handle all of the kinds of
- // types that the parameter may be.
+ // C++ [temp.deduct.type]p9:
+ //
+ // A template type argument T, a template template argument TT or a
+ // template non-type argument i can be deduced if P and A have one of
+ // the following forms:
+ //
+ // T
+ // cv-list T
if (const TemplateTypeParmType *TemplateTypeParm
= Param->getAsTemplateTypeParmType()) {
// The argument type can not be less qualified than the parameter
@@ -67,6 +153,12 @@
return false;
switch (Param->getTypeClass()) {
+ // No deduction possible for these types
+ case Type::Builtin:
+ return false;
+
+
+ // T *
case Type::Pointer: {
const PointerType *PointerArg = Arg->getAsPointerType();
if (!PointerArg)
@@ -78,6 +170,7 @@
Deduced);
}
+ // T &
case Type::LValueReference: {
const LValueReferenceType *ReferenceArg = Arg->getAsLValueReferenceType();
if (!ReferenceArg)
@@ -89,6 +182,7 @@
Deduced);
}
+ // T && [C++0x]
case Type::RValueReference: {
const RValueReferenceType *ReferenceArg = Arg->getAsRValueReferenceType();
if (!ReferenceArg)
@@ -100,6 +194,7 @@
Deduced);
}
+ // T [] (implied, but not stated explicitly)
case Type::IncompleteArray: {
const IncompleteArrayType *IncompleteArrayArg =
Context.getAsIncompleteArrayType(Arg);
@@ -111,7 +206,8 @@
IncompleteArrayArg->getElementType(),
Deduced);
}
-
+
+ // T [integer-constant]
case Type::ConstantArray: {
const ConstantArrayType *ConstantArrayArg =
Context.getAsConstantArrayType(Arg);
@@ -129,6 +225,46 @@
Deduced);
}
+ // type [i]
+ case Type::DependentSizedArray: {
+ const ArrayType *ArrayArg = dyn_cast<ArrayType>(Arg);
+ if (!ArrayArg)
+ return false;
+
+ // Check the element type of the arrays
+ const DependentSizedArrayType *DependentArrayParm
+ = cast<DependentSizedArrayType>(Param);
+ if (!DeduceTemplateArguments(Context,
+ DependentArrayParm->getElementType(),
+ ArrayArg->getElementType(),
+ Deduced))
+ return false;
+
+ // Determine the array bound is something we can deduce.
+ NonTypeTemplateParmDecl *NTTP
+ = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr());
+ if (!NTTP)
+ return true;
+
+ // We can perform template argument deduction for the given non-type
+ // template parameter.
+ assert(NTTP->getDepth() == 0 &&
+ "Cannot deduce non-type template argument at depth > 0");
+ if (const ConstantArrayType *ConstantArrayArg
+ = dyn_cast<ConstantArrayType>(ArrayArg))
+ return DeduceNonTypeTemplateArgument(Context, NTTP,
+ ConstantArrayArg->getSize(),
+ Deduced);
+ if (const DependentSizedArrayType *DependentArrayArg
+ = dyn_cast<DependentSizedArrayType>(ArrayArg))
+ return DeduceNonTypeTemplateArgument(Context, NTTP,
+ DependentArrayArg->getSizeExpr(),
+ Deduced);
+
+ // Incomplete type does not match a dependently-sized array type
+ return false;
+ }
+
default:
break;
}
@@ -141,16 +277,53 @@
DeduceTemplateArguments(ASTContext &Context, const TemplateArgument &Param,
const TemplateArgument &Arg,
llvm::SmallVectorImpl<TemplateArgument> &Deduced) {
- assert(Param.getKind() == Arg.getKind() &&
- "Template argument kind mismatch during deduction");
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, Param.getAsType(),
Arg.getAsType(), Deduced);
- default:
+ case TemplateArgument::Declaration:
+ // FIXME: Implement this check
+ assert(false && "Unimplemented template argument deduction case");
return false;
+
+ case TemplateArgument::Integral:
+ if (Arg.getKind() == TemplateArgument::Integral) {
+ // FIXME: Zero extension + sign checking here?
+ return *Param.getAsIntegral() == *Arg.getAsIntegral();
+ }
+ if (Arg.getKind() == TemplateArgument::Expression)
+ return false;
+
+ assert(false && "Type/value mismatch");
+ return false;
+
+ case TemplateArgument::Expression: {
+ if (NonTypeTemplateParmDecl *NTTP
+ = getDeducedParameterFromExpr(Param.getAsExpr())) {
+ if (Arg.getKind() == TemplateArgument::Integral)
+ // FIXME: Sign problems here
+ return DeduceNonTypeTemplateArgument(Context, NTTP,
+ *Arg.getAsIntegral(), Deduced);
+ if (Arg.getKind() == TemplateArgument::Expression)
+ return DeduceNonTypeTemplateArgument(Context, NTTP, Arg.getAsExpr(),
+ Deduced);
+
+ assert(false && "Type/value mismatch");
+ return false;
+ }
+
+ // Can't deduce anything, but that's okay.
+ return true;
+ }
}
+
+ return true;
}
static bool
@@ -167,11 +340,50 @@
}
-bool
+TemplateArgumentList *
Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
const TemplateArgumentList &TemplateArgs) {
+ // Deduce the template arguments for the partial specialization
llvm::SmallVector<TemplateArgument, 4> Deduced;
Deduced.resize(Partial->getTemplateParameters()->size());
- return ::DeduceTemplateArguments(Context, Partial->getTemplateArgs(),
- TemplateArgs, Deduced);
+ if (! ::DeduceTemplateArguments(Context, Partial->getTemplateArgs(),
+ TemplateArgs, Deduced))
+ return 0;
+
+ // FIXME: Substitute the deduced template arguments into the template
+ // arguments of the class template partial specialization; the resulting
+ // template arguments should match TemplateArgs exactly.
+
+ for (unsigned I = 0, N = Deduced.size(); I != N; ++I) {
+ TemplateArgument &Arg = Deduced[I];
+
+ // FIXME: If this template argument was not deduced, but the corresponding
+ // template parameter has a default argument, instantiate the default
+ // argument.
+ if (Arg.isNull()) // FIXME: Result->Destroy(Context);
+ return 0;
+
+ if (Arg.getKind() == TemplateArgument::Integral) {
+ // FIXME: Instantiate the type, but we need some context!
+ const NonTypeTemplateParmDecl *Parm
+ = cast<NonTypeTemplateParmDecl>(Partial->getTemplateParameters()
+ ->getParam(I));
+ // QualType T = InstantiateType(Parm->getType(), *Result,
+ // Parm->getLocation(), Parm->getDeclName());
+ // if (T.isNull()) // FIXME: Result->Destroy(Context);
+ // return 0;
+ QualType T = Parm->getType();
+
+ // FIXME: Make sure we didn't overflow our data type!
+ llvm::APSInt &Value = *Arg.getAsIntegral();
+ unsigned AllowedBits = Context.getTypeSize(T);
+ if (Value.getBitWidth() != AllowedBits)
+ Value.extOrTrunc(AllowedBits);
+ Value.setIsSigned(T->isSignedIntegerType());
+ Arg.setIntegralType(T);
+ }
+ }
+
+ return new (Context) TemplateArgumentList(Context, Deduced.data(),
+ Deduced.size(), /*CopyArgs=*/true);
}
Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp Thu Jun 4 19:53:49 2009
@@ -833,21 +833,23 @@
// Determine whether any class template partial specializations
// match the given template arguments.
- llvm::SmallVector<ClassTemplatePartialSpecializationDecl *, 4> Matched;
+ typedef std::pair<ClassTemplatePartialSpecializationDecl *,
+ TemplateArgumentList *> MatchResult;
+ llvm::SmallVector<MatchResult, 4> Matched;
for (llvm::FoldingSet<ClassTemplatePartialSpecializationDecl>::iterator
Partial = Template->getPartialSpecializations().begin(),
PartialEnd = Template->getPartialSpecializations().end();
Partial != PartialEnd;
++Partial) {
- if (DeduceTemplateArguments(&*Partial, ClassTemplateSpec->getTemplateArgs()))
- Matched.push_back(&*Partial);
+ if (TemplateArgumentList *Deduced
+ = DeduceTemplateArguments(&*Partial,
+ ClassTemplateSpec->getTemplateArgs()))
+ Matched.push_back(std::make_pair(&*Partial, Deduced));
}
if (Matched.size() == 1) {
- Pattern = Matched[0];
- // FIXME: set TemplateArgs to the template arguments of the
- // partial specialization, instantiated with the deduced template
- // arguments.
+ Pattern = Matched[0].first;
+ TemplateArgs = Matched[0].second;
} else if (Matched.size() > 1) {
// FIXME: Implement partial ordering of class template partial
// specializations.
@@ -860,9 +862,17 @@
ExplicitInstantiation? TSK_ExplicitInstantiation
: TSK_ImplicitInstantiation);
- return InstantiateClass(ClassTemplateSpec->getLocation(),
- ClassTemplateSpec, Pattern, *TemplateArgs,
- ExplicitInstantiation);
+ bool Result = InstantiateClass(ClassTemplateSpec->getLocation(),
+ ClassTemplateSpec, Pattern, *TemplateArgs,
+ ExplicitInstantiation);
+
+ for (unsigned I = 0, N = Matched.size(); I != N; ++I) {
+ // FIXME: Implement TemplateArgumentList::Destroy!
+ // if (Matched[I].first != Pattern)
+ // Matched[I].second->Destroy(Context);
+ }
+
+ return Result;
}
/// \brief Instantiate the definitions of all of the member of the
Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateExpr.cpp?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateInstantiateExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateInstantiateExpr.cpp Thu Jun 4 19:53:49 2009
@@ -119,12 +119,13 @@
T->isWideCharType(),
T,
E->getSourceRange().getBegin()));
- else if (T->isBooleanType())
+ if (T->isBooleanType())
return SemaRef.Owned(new (SemaRef.Context) CXXBoolLiteralExpr(
Arg.getAsIntegral()->getBoolValue(),
T,
E->getSourceRange().getBegin()));
+ assert(Arg.getAsIntegral()->getBitWidth() == SemaRef.Context.getIntWidth(T));
return SemaRef.Owned(new (SemaRef.Context) IntegerLiteral(
*Arg.getAsIntegral(),
T,
Added: cfe/trunk/test/SemaTemplate/ackermann.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/ackermann.cpp?rev=72909&view=auto
==============================================================================
--- cfe/trunk/test/SemaTemplate/ackermann.cpp (added)
+++ cfe/trunk/test/SemaTemplate/ackermann.cpp Thu Jun 4 19:53:49 2009
@@ -0,0 +1,37 @@
+// RUN: clang-cc -fsyntax-only -ftemplate-depth=1000 -verify %s
+
+// template<unsigned M, unsigned N>
+// struct Ackermann {
+// enum {
+// value = M ? (N ? Ackermann<M-1, Ackermann<M-1, N-1> >::value
+// : Ackermann<M-1, 1>::value)
+// : N + 1
+// };
+// };
+
+template<unsigned M, unsigned N>
+struct Ackermann {
+ enum {
+ value = Ackermann<M-1, Ackermann<M, N-1>::value >::value
+ };
+};
+
+template<unsigned M> struct Ackermann<M, 0> {
+ enum {
+ value = Ackermann<M-1, 1>::value
+ };
+};
+
+template<unsigned N> struct Ackermann<0, N> {
+ enum {
+ value = N + 1
+ };
+};
+
+template<> struct Ackermann<0, 0> {
+ enum {
+ value = 1
+ };
+};
+
+int g0[Ackermann<3, 8>::value == 2045 ? 1 : -1];
Modified: cfe/trunk/test/SemaTemplate/temp_class_spec.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaTemplate/temp_class_spec.cpp?rev=72909&r1=72908&r2=72909&view=diff
==============================================================================
--- cfe/trunk/test/SemaTemplate/temp_class_spec.cpp (original)
+++ cfe/trunk/test/SemaTemplate/temp_class_spec.cpp Thu Jun 4 19:53:49 2009
@@ -51,6 +51,19 @@
int is_same3[is_same<int_ptr, int>::value? -1 : 1];
template<typename T>
+struct remove_reference {
+ typedef T type;
+};
+
+template<typename T>
+struct remove_reference<T&> {
+ typedef T type;
+};
+
+int remove_ref0[is_same<remove_reference<int>::type, int>::value? 1 : -1];
+int remove_ref1[is_same<remove_reference<int&>::type, int>::value? 1 : -1];
+
+template<typename T>
struct is_incomplete_array {
static const bool value = false;
};
@@ -79,3 +92,13 @@
int array_with_4_elements1[is_array_with_4_elements<int[1]>::value ? -1 : 1];
int array_with_4_elements2[is_array_with_4_elements<int[4]>::value ? 1 : -1];
int array_with_4_elements3[is_array_with_4_elements<int[4][2]>::value ? 1 : -1];
+
+template<typename T>
+struct get_array_size;
+
+template<typename T, unsigned N>
+struct get_array_size<T[N]> {
+ static const unsigned value = N;
+};
+
+int array_size0[get_array_size<int[12]>::value == 12? 1 : -1];
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