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llvm-project/clang/lib/Sema/SemaTemplateVariadic.cpp
Bruno Ricci 70ad396bc4 [Sema][NFCI] Don't allocate storage for the various CorrectionCandidateCallback unless we are going to do some typo correction 
The various CorrectionCandidateCallbacks are currently heap-allocated
unconditionally. This was needed because of delayed typo correction.
However these allocations represent currently 15.4% of all allocations
(number of allocations) when parsing all of Boost (!), mostly because
of ParseCastExpression, ParseStatementOrDeclarationAfterAttrtibutes
and isCXXDeclarationSpecifier. Note that all of these callback objects
are small. Let's not do this.

Instead initially allocate the callback on the stack, and only do a
heap allocation if we are going to do some typo correction. Do this by:

1. Adding a clone function to each callback, which will do a polymorphic
   clone of the callback. This clone function is required to be implemented
   by every callback (of which there is a fair amount). Make sure this is
   the case by making it pure virtual.

2. Use this clone function when we are going to try to correct a typo.

This additionally cut the time of -fsyntax-only on all of Boost by 0.5%
(not that much, but still something). No functional changes intended.

Differential Revision: https://reviews.llvm.org/D58827

Reviewed By: rnk

llvm-svn: 356925
2019-03-25 17:08:51 +00:00

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//===------- SemaTemplateVariadic.cpp - C++ Variadic Templates ------------===/
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//===----------------------------------------------------------------------===/
//
// This file implements semantic analysis for C++0x variadic templates.
//===----------------------------------------------------------------------===/
#include "clang/Sema/Sema.h"
#include "TypeLocBuilder.h"
#include "clang/AST/Expr.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
using namespace clang;
//----------------------------------------------------------------------------
// Visitor that collects unexpanded parameter packs
//----------------------------------------------------------------------------
namespace {
/// A class that collects unexpanded parameter packs.
class CollectUnexpandedParameterPacksVisitor :
public RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
{
typedef RecursiveASTVisitor<CollectUnexpandedParameterPacksVisitor>
inherited;
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded;
bool InLambda = false;
unsigned DepthLimit = (unsigned)-1;
void addUnexpanded(NamedDecl *ND, SourceLocation Loc = SourceLocation()) {
if (auto *PVD = dyn_cast<ParmVarDecl>(ND)) {
// For now, the only problematic case is a generic lambda's templated
// call operator, so we don't need to look for all the other ways we
// could have reached a dependent parameter pack.
auto *FD = dyn_cast<FunctionDecl>(PVD->getDeclContext());
auto *FTD = FD ? FD->getDescribedFunctionTemplate() : nullptr;
if (FTD && FTD->getTemplateParameters()->getDepth() >= DepthLimit)
return;
} else if (getDepthAndIndex(ND).first >= DepthLimit)
return;
Unexpanded.push_back({ND, Loc});
}
void addUnexpanded(const TemplateTypeParmType *T,
SourceLocation Loc = SourceLocation()) {
if (T->getDepth() < DepthLimit)
Unexpanded.push_back({T, Loc});
}
public:
explicit CollectUnexpandedParameterPacksVisitor(
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded)
: Unexpanded(Unexpanded) {}
bool shouldWalkTypesOfTypeLocs() const { return false; }
//------------------------------------------------------------------------
// Recording occurrences of (unexpanded) parameter packs.
//------------------------------------------------------------------------
/// Record occurrences of template type parameter packs.
bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
if (TL.getTypePtr()->isParameterPack())
addUnexpanded(TL.getTypePtr(), TL.getNameLoc());
return true;
}
/// Record occurrences of template type parameter packs
/// when we don't have proper source-location information for
/// them.
///
/// Ideally, this routine would never be used.
bool VisitTemplateTypeParmType(TemplateTypeParmType *T) {
if (T->isParameterPack())
addUnexpanded(T);
return true;
}
/// Record occurrences of function and non-type template
/// parameter packs in an expression.
bool VisitDeclRefExpr(DeclRefExpr *E) {
if (E->getDecl()->isParameterPack())
addUnexpanded(E->getDecl(), E->getLocation());
return true;
}
/// Record occurrences of template template parameter packs.
bool TraverseTemplateName(TemplateName Template) {
if (auto *TTP = dyn_cast_or_null<TemplateTemplateParmDecl>(
Template.getAsTemplateDecl())) {
if (TTP->isParameterPack())
addUnexpanded(TTP);
}
return inherited::TraverseTemplateName(Template);
}
/// Suppress traversal into Objective-C container literal
/// elements that are pack expansions.
bool TraverseObjCDictionaryLiteral(ObjCDictionaryLiteral *E) {
if (!E->containsUnexpandedParameterPack())
return true;
for (unsigned I = 0, N = E->getNumElements(); I != N; ++I) {
ObjCDictionaryElement Element = E->getKeyValueElement(I);
if (Element.isPackExpansion())
continue;
TraverseStmt(Element.Key);
TraverseStmt(Element.Value);
}
return true;
}
//------------------------------------------------------------------------
// Pruning the search for unexpanded parameter packs.
//------------------------------------------------------------------------
/// Suppress traversal into statements and expressions that
/// do not contain unexpanded parameter packs.
bool TraverseStmt(Stmt *S) {
Expr *E = dyn_cast_or_null<Expr>(S);
if ((E && E->containsUnexpandedParameterPack()) || InLambda)
return inherited::TraverseStmt(S);
return true;
}
/// Suppress traversal into types that do not contain
/// unexpanded parameter packs.
bool TraverseType(QualType T) {
if ((!T.isNull() && T->containsUnexpandedParameterPack()) || InLambda)
return inherited::TraverseType(T);
return true;
}
/// Suppress traversal into types with location information
/// that do not contain unexpanded parameter packs.
bool TraverseTypeLoc(TypeLoc TL) {
if ((!TL.getType().isNull() &&
TL.getType()->containsUnexpandedParameterPack()) ||
InLambda)
return inherited::TraverseTypeLoc(TL);
return true;
}
/// Suppress traversal of parameter packs.
bool TraverseDecl(Decl *D) {
// A function parameter pack is a pack expansion, so cannot contain
// an unexpanded parameter pack. Likewise for a template parameter
// pack that contains any references to other packs.
if (D && D->isParameterPack())
return true;
return inherited::TraverseDecl(D);
}
/// Suppress traversal of pack-expanded attributes.
bool TraverseAttr(Attr *A) {
if (A->isPackExpansion())
return true;
return inherited::TraverseAttr(A);
}
/// Suppress traversal of pack expansion expressions and types.
///@{
bool TraversePackExpansionType(PackExpansionType *T) { return true; }
bool TraversePackExpansionTypeLoc(PackExpansionTypeLoc TL) { return true; }
bool TraversePackExpansionExpr(PackExpansionExpr *E) { return true; }
bool TraverseCXXFoldExpr(CXXFoldExpr *E) { return true; }
///@}
/// Suppress traversal of using-declaration pack expansion.
bool TraverseUnresolvedUsingValueDecl(UnresolvedUsingValueDecl *D) {
if (D->isPackExpansion())
return true;
return inherited::TraverseUnresolvedUsingValueDecl(D);
}
/// Suppress traversal of using-declaration pack expansion.
bool TraverseUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D) {
if (D->isPackExpansion())
return true;
return inherited::TraverseUnresolvedUsingTypenameDecl(D);
}
/// Suppress traversal of template argument pack expansions.
bool TraverseTemplateArgument(const TemplateArgument &Arg) {
if (Arg.isPackExpansion())
return true;
return inherited::TraverseTemplateArgument(Arg);
}
/// Suppress traversal of template argument pack expansions.
bool TraverseTemplateArgumentLoc(const TemplateArgumentLoc &ArgLoc) {
if (ArgLoc.getArgument().isPackExpansion())
return true;
return inherited::TraverseTemplateArgumentLoc(ArgLoc);
}
/// Suppress traversal of base specifier pack expansions.
bool TraverseCXXBaseSpecifier(const CXXBaseSpecifier &Base) {
if (Base.isPackExpansion())
return true;
return inherited::TraverseCXXBaseSpecifier(Base);
}
/// Suppress traversal of mem-initializer pack expansions.
bool TraverseConstructorInitializer(CXXCtorInitializer *Init) {
if (Init->isPackExpansion())
return true;
return inherited::TraverseConstructorInitializer(Init);
}
/// Note whether we're traversing a lambda containing an unexpanded
/// parameter pack. In this case, the unexpanded pack can occur anywhere,
/// including all the places where we normally wouldn't look. Within a
/// lambda, we don't propagate the 'contains unexpanded parameter pack' bit
/// outside an expression.
bool TraverseLambdaExpr(LambdaExpr *Lambda) {
// The ContainsUnexpandedParameterPack bit on a lambda is always correct,
// even if it's contained within another lambda.
if (!Lambda->containsUnexpandedParameterPack())
return true;
bool WasInLambda = InLambda;
unsigned OldDepthLimit = DepthLimit;
InLambda = true;
if (auto *TPL = Lambda->getTemplateParameterList())
DepthLimit = TPL->getDepth();
inherited::TraverseLambdaExpr(Lambda);
InLambda = WasInLambda;
DepthLimit = OldDepthLimit;
return true;
}
/// Suppress traversal within pack expansions in lambda captures.
bool TraverseLambdaCapture(LambdaExpr *Lambda, const LambdaCapture *C,
Expr *Init) {
if (C->isPackExpansion())
return true;
return inherited::TraverseLambdaCapture(Lambda, C, Init);
}
};
}
/// Determine whether it's possible for an unexpanded parameter pack to
/// be valid in this location. This only happens when we're in a declaration
/// that is nested within an expression that could be expanded, such as a
/// lambda-expression within a function call.
///
/// This is conservatively correct, but may claim that some unexpanded packs are
/// permitted when they are not.
bool Sema::isUnexpandedParameterPackPermitted() {
for (auto *SI : FunctionScopes)
if (isa<sema::LambdaScopeInfo>(SI))
return true;
return false;
}
/// Diagnose all of the unexpanded parameter packs in the given
/// vector.
bool
Sema::DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
UnexpandedParameterPackContext UPPC,
ArrayRef<UnexpandedParameterPack> Unexpanded) {
if (Unexpanded.empty())
return false;
// If we are within a lambda expression and referencing a pack that is not
// a parameter of the lambda itself, that lambda contains an unexpanded
// parameter pack, and we are done.
// FIXME: Store 'Unexpanded' on the lambda so we don't need to recompute it
// later.
SmallVector<UnexpandedParameterPack, 4> LambdaParamPackReferences;
for (unsigned N = FunctionScopes.size(); N; --N) {
sema::FunctionScopeInfo *Func = FunctionScopes[N-1];
// We do not permit pack expansion that would duplicate a statement
// expression, not even within a lambda.
// FIXME: We could probably support this for statement expressions that do
// not contain labels, and for pack expansions that expand both the stmt
// expr and the enclosing lambda.
if (std::any_of(
Func->CompoundScopes.begin(), Func->CompoundScopes.end(),
[](sema::CompoundScopeInfo &CSI) { return CSI.IsStmtExpr; }))
break;
if (auto *LSI = dyn_cast<sema::LambdaScopeInfo>(Func)) {
if (N == FunctionScopes.size()) {
for (auto &Param : Unexpanded) {
auto *PD = dyn_cast_or_null<ParmVarDecl>(
Param.first.dyn_cast<NamedDecl *>());
if (PD && PD->getDeclContext() == LSI->CallOperator)
LambdaParamPackReferences.push_back(Param);
}
}
// If we have references to a parameter pack of the innermost enclosing
// lambda, only diagnose those ones. We don't know whether any other
// unexpanded parameters referenced herein are actually unexpanded;
// they might be expanded at an outer level.
if (!LambdaParamPackReferences.empty()) {
Unexpanded = LambdaParamPackReferences;
break;
}
LSI->ContainsUnexpandedParameterPack = true;
return false;
}
}
SmallVector<SourceLocation, 4> Locations;
SmallVector<IdentifierInfo *, 4> Names;
llvm::SmallPtrSet<IdentifierInfo *, 4> NamesKnown;
for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
IdentifierInfo *Name = nullptr;
if (const TemplateTypeParmType *TTP
= Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>())
Name = TTP->getIdentifier();
else
Name = Unexpanded[I].first.get<NamedDecl *>()->getIdentifier();
if (Name && NamesKnown.insert(Name).second)
Names.push_back(Name);
if (Unexpanded[I].second.isValid())
Locations.push_back(Unexpanded[I].second);
}
DiagnosticBuilder DB = Diag(Loc, diag::err_unexpanded_parameter_pack)
<< (int)UPPC << (int)Names.size();
for (size_t I = 0, E = std::min(Names.size(), (size_t)2); I != E; ++I)
DB << Names[I];
for (unsigned I = 0, N = Locations.size(); I != N; ++I)
DB << SourceRange(Locations[I]);
return true;
}
bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc,
TypeSourceInfo *T,
UnexpandedParameterPackContext UPPC) {
// C++0x [temp.variadic]p5:
// An appearance of a name of a parameter pack that is not expanded is
// ill-formed.
if (!T->getType()->containsUnexpandedParameterPack())
return false;
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(
T->getTypeLoc());
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded);
}
bool Sema::DiagnoseUnexpandedParameterPack(Expr *E,
UnexpandedParameterPackContext UPPC) {
// C++0x [temp.variadic]p5:
// An appearance of a name of a parameter pack that is not expanded is
// ill-formed.
if (!E->containsUnexpandedParameterPack())
return false;
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseStmt(E);
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(E->getBeginLoc(), UPPC, Unexpanded);
}
bool Sema::DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
UnexpandedParameterPackContext UPPC) {
// C++0x [temp.variadic]p5:
// An appearance of a name of a parameter pack that is not expanded is
// ill-formed.
if (!SS.getScopeRep() ||
!SS.getScopeRep()->containsUnexpandedParameterPack())
return false;
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseNestedNameSpecifier(SS.getScopeRep());
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(SS.getRange().getBegin(),
UPPC, Unexpanded);
}
bool Sema::DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
UnexpandedParameterPackContext UPPC) {
// C++0x [temp.variadic]p5:
// An appearance of a name of a parameter pack that is not expanded is
// ill-formed.
switch (NameInfo.getName().getNameKind()) {
case DeclarationName::Identifier:
case DeclarationName::ObjCZeroArgSelector:
case DeclarationName::ObjCOneArgSelector:
case DeclarationName::ObjCMultiArgSelector:
case DeclarationName::CXXOperatorName:
case DeclarationName::CXXLiteralOperatorName:
case DeclarationName::CXXUsingDirective:
case DeclarationName::CXXDeductionGuideName:
return false;
case DeclarationName::CXXConstructorName:
case DeclarationName::CXXDestructorName:
case DeclarationName::CXXConversionFunctionName:
// FIXME: We shouldn't need this null check!
if (TypeSourceInfo *TSInfo = NameInfo.getNamedTypeInfo())
return DiagnoseUnexpandedParameterPack(NameInfo.getLoc(), TSInfo, UPPC);
if (!NameInfo.getName().getCXXNameType()->containsUnexpandedParameterPack())
return false;
break;
}
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseType(NameInfo.getName().getCXXNameType());
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(NameInfo.getLoc(), UPPC, Unexpanded);
}
bool Sema::DiagnoseUnexpandedParameterPack(SourceLocation Loc,
TemplateName Template,
UnexpandedParameterPackContext UPPC) {
if (Template.isNull() || !Template.containsUnexpandedParameterPack())
return false;
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseTemplateName(Template);
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(Loc, UPPC, Unexpanded);
}
bool Sema::DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
UnexpandedParameterPackContext UPPC) {
if (Arg.getArgument().isNull() ||
!Arg.getArgument().containsUnexpandedParameterPack())
return false;
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseTemplateArgumentLoc(Arg);
assert(!Unexpanded.empty() && "Unable to find unexpanded parameter packs");
return DiagnoseUnexpandedParameterPacks(Arg.getLocation(), UPPC, Unexpanded);
}
void Sema::collectUnexpandedParameterPacks(TemplateArgument Arg,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseTemplateArgument(Arg);
}
void Sema::collectUnexpandedParameterPacks(TemplateArgumentLoc Arg,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseTemplateArgumentLoc(Arg);
}
void Sema::collectUnexpandedParameterPacks(QualType T,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(T);
}
void Sema::collectUnexpandedParameterPacks(TypeLoc TL,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseTypeLoc(TL);
}
void Sema::collectUnexpandedParameterPacks(
NestedNameSpecifierLoc NNS,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseNestedNameSpecifierLoc(NNS);
}
void Sema::collectUnexpandedParameterPacks(
const DeclarationNameInfo &NameInfo,
SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {
CollectUnexpandedParameterPacksVisitor(Unexpanded)
.TraverseDeclarationNameInfo(NameInfo);
}
ParsedTemplateArgument
Sema::ActOnPackExpansion(const ParsedTemplateArgument &Arg,
SourceLocation EllipsisLoc) {
if (Arg.isInvalid())
return Arg;
switch (Arg.getKind()) {
case ParsedTemplateArgument::Type: {
TypeResult Result = ActOnPackExpansion(Arg.getAsType(), EllipsisLoc);
if (Result.isInvalid())
return ParsedTemplateArgument();
return ParsedTemplateArgument(Arg.getKind(), Result.get().getAsOpaquePtr(),
Arg.getLocation());
}
case ParsedTemplateArgument::NonType: {
ExprResult Result = ActOnPackExpansion(Arg.getAsExpr(), EllipsisLoc);
if (Result.isInvalid())
return ParsedTemplateArgument();
return ParsedTemplateArgument(Arg.getKind(), Result.get(),
Arg.getLocation());
}
case ParsedTemplateArgument::Template:
if (!Arg.getAsTemplate().get().containsUnexpandedParameterPack()) {
SourceRange R(Arg.getLocation());
if (Arg.getScopeSpec().isValid())
R.setBegin(Arg.getScopeSpec().getBeginLoc());
Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
<< R;
return ParsedTemplateArgument();
}
return Arg.getTemplatePackExpansion(EllipsisLoc);
}
llvm_unreachable("Unhandled template argument kind?");
}
TypeResult Sema::ActOnPackExpansion(ParsedType Type,
SourceLocation EllipsisLoc) {
TypeSourceInfo *TSInfo;
GetTypeFromParser(Type, &TSInfo);
if (!TSInfo)
return true;
TypeSourceInfo *TSResult = CheckPackExpansion(TSInfo, EllipsisLoc, None);
if (!TSResult)
return true;
return CreateParsedType(TSResult->getType(), TSResult);
}
TypeSourceInfo *
Sema::CheckPackExpansion(TypeSourceInfo *Pattern, SourceLocation EllipsisLoc,
Optional<unsigned> NumExpansions) {
// Create the pack expansion type and source-location information.
QualType Result = CheckPackExpansion(Pattern->getType(),
Pattern->getTypeLoc().getSourceRange(),
EllipsisLoc, NumExpansions);
if (Result.isNull())
return nullptr;
TypeLocBuilder TLB;
TLB.pushFullCopy(Pattern->getTypeLoc());
PackExpansionTypeLoc TL = TLB.push<PackExpansionTypeLoc>(Result);
TL.setEllipsisLoc(EllipsisLoc);
return TLB.getTypeSourceInfo(Context, Result);
}
QualType Sema::CheckPackExpansion(QualType Pattern, SourceRange PatternRange,
SourceLocation EllipsisLoc,
Optional<unsigned> NumExpansions) {
// C++0x [temp.variadic]p5:
// The pattern of a pack expansion shall name one or more
// parameter packs that are not expanded by a nested pack
// expansion.
if (!Pattern->containsUnexpandedParameterPack()) {
Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
<< PatternRange;
return QualType();
}
return Context.getPackExpansionType(Pattern, NumExpansions);
}
ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
return CheckPackExpansion(Pattern, EllipsisLoc, None);
}
ExprResult Sema::CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
Optional<unsigned> NumExpansions) {
if (!Pattern)
return ExprError();
// C++0x [temp.variadic]p5:
// The pattern of a pack expansion shall name one or more
// parameter packs that are not expanded by a nested pack
// expansion.
if (!Pattern->containsUnexpandedParameterPack()) {
Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
<< Pattern->getSourceRange();
return ExprError();
}
// Create the pack expansion expression and source-location information.
return new (Context)
PackExpansionExpr(Context.DependentTy, Pattern, EllipsisLoc, NumExpansions);
}
bool Sema::CheckParameterPacksForExpansion(
SourceLocation EllipsisLoc, SourceRange PatternRange,
ArrayRef<UnexpandedParameterPack> Unexpanded,
const MultiLevelTemplateArgumentList &TemplateArgs, bool &ShouldExpand,
bool &RetainExpansion, Optional<unsigned> &NumExpansions) {
ShouldExpand = true;
RetainExpansion = false;
std::pair<IdentifierInfo *, SourceLocation> FirstPack;
bool HaveFirstPack = false;
Optional<unsigned> NumPartialExpansions;
SourceLocation PartiallySubstitutedPackLoc;
for (ArrayRef<UnexpandedParameterPack>::iterator i = Unexpanded.begin(),
end = Unexpanded.end();
i != end; ++i) {
// Compute the depth and index for this parameter pack.
unsigned Depth = 0, Index = 0;
IdentifierInfo *Name;
bool IsFunctionParameterPack = false;
if (const TemplateTypeParmType *TTP
= i->first.dyn_cast<const TemplateTypeParmType *>()) {
Depth = TTP->getDepth();
Index = TTP->getIndex();
Name = TTP->getIdentifier();
} else {
NamedDecl *ND = i->first.get<NamedDecl *>();
if (isa<ParmVarDecl>(ND))
IsFunctionParameterPack = true;
else
std::tie(Depth, Index) = getDepthAndIndex(ND);
Name = ND->getIdentifier();
}
// Determine the size of this argument pack.
unsigned NewPackSize;
if (IsFunctionParameterPack) {
// Figure out whether we're instantiating to an argument pack or not.
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation
= CurrentInstantiationScope->findInstantiationOf(
i->first.get<NamedDecl *>());
if (Instantiation->is<DeclArgumentPack *>()) {
// We could expand this function parameter pack.
NewPackSize = Instantiation->get<DeclArgumentPack *>()->size();
} else {
// We can't expand this function parameter pack, so we can't expand
// the pack expansion.
ShouldExpand = false;
continue;
}
} else {
// If we don't have a template argument at this depth/index, then we
// cannot expand the pack expansion. Make a note of this, but we still
// want to check any parameter packs we *do* have arguments for.
if (Depth >= TemplateArgs.getNumLevels() ||
!TemplateArgs.hasTemplateArgument(Depth, Index)) {
ShouldExpand = false;
continue;
}
// Determine the size of the argument pack.
NewPackSize = TemplateArgs(Depth, Index).pack_size();
}
// C++0x [temp.arg.explicit]p9:
// Template argument deduction can extend the sequence of template
// arguments corresponding to a template parameter pack, even when the
// sequence contains explicitly specified template arguments.
if (!IsFunctionParameterPack && CurrentInstantiationScope) {
if (NamedDecl *PartialPack
= CurrentInstantiationScope->getPartiallySubstitutedPack()){
unsigned PartialDepth, PartialIndex;
std::tie(PartialDepth, PartialIndex) = getDepthAndIndex(PartialPack);
if (PartialDepth == Depth && PartialIndex == Index) {
RetainExpansion = true;
// We don't actually know the new pack size yet.
NumPartialExpansions = NewPackSize;
PartiallySubstitutedPackLoc = i->second;
continue;
}
}
}
if (!NumExpansions) {
// The is the first pack we've seen for which we have an argument.
// Record it.
NumExpansions = NewPackSize;
FirstPack.first = Name;
FirstPack.second = i->second;
HaveFirstPack = true;
continue;
}
if (NewPackSize != *NumExpansions) {
// C++0x [temp.variadic]p5:
// All of the parameter packs expanded by a pack expansion shall have
// the same number of arguments specified.
if (HaveFirstPack)
Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict)
<< FirstPack.first << Name << *NumExpansions << NewPackSize
<< SourceRange(FirstPack.second) << SourceRange(i->second);
else
Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict_multilevel)
<< Name << *NumExpansions << NewPackSize
<< SourceRange(i->second);
return true;
}
}
// If we're performing a partial expansion but we also have a full expansion,
// expand to the number of common arguments. For example, given:
//
// template<typename ...T> struct A {
// template<typename ...U> void f(pair<T, U>...);
// };
//
// ... a call to 'A<int, int>().f<int>' should expand the pack once and
// retain an expansion.
if (NumPartialExpansions) {
if (NumExpansions && *NumExpansions < *NumPartialExpansions) {
NamedDecl *PartialPack =
CurrentInstantiationScope->getPartiallySubstitutedPack();
Diag(EllipsisLoc, diag::err_pack_expansion_length_conflict_partial)
<< PartialPack << *NumPartialExpansions << *NumExpansions
<< SourceRange(PartiallySubstitutedPackLoc);
return true;
}
NumExpansions = NumPartialExpansions;
}
return false;
}
Optional<unsigned> Sema::getNumArgumentsInExpansion(QualType T,
const MultiLevelTemplateArgumentList &TemplateArgs) {
QualType Pattern = cast<PackExpansionType>(T)->getPattern();
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor(Unexpanded).TraverseType(Pattern);
Optional<unsigned> Result;
for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
// Compute the depth and index for this parameter pack.
unsigned Depth;
unsigned Index;
if (const TemplateTypeParmType *TTP
= Unexpanded[I].first.dyn_cast<const TemplateTypeParmType *>()) {
Depth = TTP->getDepth();
Index = TTP->getIndex();
} else {
NamedDecl *ND = Unexpanded[I].first.get<NamedDecl *>();
if (isa<ParmVarDecl>(ND)) {
// Function parameter pack.
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Instantiation
= CurrentInstantiationScope->findInstantiationOf(
Unexpanded[I].first.get<NamedDecl *>());
if (Instantiation->is<Decl*>())
// The pattern refers to an unexpanded pack. We're not ready to expand
// this pack yet.
return None;
unsigned Size = Instantiation->get<DeclArgumentPack *>()->size();
assert((!Result || *Result == Size) && "inconsistent pack sizes");
Result = Size;
continue;
}
std::tie(Depth, Index) = getDepthAndIndex(ND);
}
if (Depth >= TemplateArgs.getNumLevels() ||
!TemplateArgs.hasTemplateArgument(Depth, Index))
// The pattern refers to an unknown template argument. We're not ready to
// expand this pack yet.
return None;
// Determine the size of the argument pack.
unsigned Size = TemplateArgs(Depth, Index).pack_size();
assert((!Result || *Result == Size) && "inconsistent pack sizes");
Result = Size;
}
return Result;
}
bool Sema::containsUnexpandedParameterPacks(Declarator &D) {
const DeclSpec &DS = D.getDeclSpec();
switch (DS.getTypeSpecType()) {
case TST_typename:
case TST_typeofType:
case TST_underlyingType:
case TST_atomic: {
QualType T = DS.getRepAsType().get();
if (!T.isNull() && T->containsUnexpandedParameterPack())
return true;
break;
}
case TST_typeofExpr:
case TST_decltype:
if (DS.getRepAsExpr() &&
DS.getRepAsExpr()->containsUnexpandedParameterPack())
return true;
break;
case TST_unspecified:
case TST_void:
case TST_char:
case TST_wchar:
case TST_char8:
case TST_char16:
case TST_char32:
case TST_int:
case TST_int128:
case TST_half:
case TST_float:
case TST_double:
case TST_Accum:
case TST_Fract:
case TST_Float16:
case TST_float128:
case TST_bool:
case TST_decimal32:
case TST_decimal64:
case TST_decimal128:
case TST_enum:
case TST_union:
case TST_struct:
case TST_interface:
case TST_class:
case TST_auto:
case TST_auto_type:
case TST_decltype_auto:
#define GENERIC_IMAGE_TYPE(ImgType, Id) case TST_##ImgType##_t:
#include "clang/Basic/OpenCLImageTypes.def"
case TST_unknown_anytype:
case TST_error:
break;
}
for (unsigned I = 0, N = D.getNumTypeObjects(); I != N; ++I) {
const DeclaratorChunk &Chunk = D.getTypeObject(I);
switch (Chunk.Kind) {
case DeclaratorChunk::Pointer:
case DeclaratorChunk::Reference:
case DeclaratorChunk::Paren:
case DeclaratorChunk::Pipe:
case DeclaratorChunk::BlockPointer:
// These declarator chunks cannot contain any parameter packs.
break;
case DeclaratorChunk::Array:
if (Chunk.Arr.NumElts &&
Chunk.Arr.NumElts->containsUnexpandedParameterPack())
return true;
break;
case DeclaratorChunk::Function:
for (unsigned i = 0, e = Chunk.Fun.NumParams; i != e; ++i) {
ParmVarDecl *Param = cast<ParmVarDecl>(Chunk.Fun.Params[i].Param);
QualType ParamTy = Param->getType();
assert(!ParamTy.isNull() && "Couldn't parse type?");
if (ParamTy->containsUnexpandedParameterPack()) return true;
}
if (Chunk.Fun.getExceptionSpecType() == EST_Dynamic) {
for (unsigned i = 0; i != Chunk.Fun.getNumExceptions(); ++i) {
if (Chunk.Fun.Exceptions[i]
.Ty.get()
->containsUnexpandedParameterPack())
return true;
}
} else if (isComputedNoexcept(Chunk.Fun.getExceptionSpecType()) &&
Chunk.Fun.NoexceptExpr->containsUnexpandedParameterPack())
return true;
if (Chunk.Fun.hasTrailingReturnType()) {
QualType T = Chunk.Fun.getTrailingReturnType().get();
if (!T.isNull() && T->containsUnexpandedParameterPack())
return true;
}
break;
case DeclaratorChunk::MemberPointer:
if (Chunk.Mem.Scope().getScopeRep() &&
Chunk.Mem.Scope().getScopeRep()->containsUnexpandedParameterPack())
return true;
break;
}
}
return false;
}
namespace {
// Callback to only accept typo corrections that refer to parameter packs.
class ParameterPackValidatorCCC final : public CorrectionCandidateCallback {
public:
bool ValidateCandidate(const TypoCorrection &candidate) override {
NamedDecl *ND = candidate.getCorrectionDecl();
return ND && ND->isParameterPack();
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return llvm::make_unique<ParameterPackValidatorCCC>(*this);
}
};
}
/// Called when an expression computing the size of a parameter pack
/// is parsed.
///
/// \code
/// template<typename ...Types> struct count {
/// static const unsigned value = sizeof...(Types);
/// };
/// \endcode
///
//
/// \param OpLoc The location of the "sizeof" keyword.
/// \param Name The name of the parameter pack whose size will be determined.
/// \param NameLoc The source location of the name of the parameter pack.
/// \param RParenLoc The location of the closing parentheses.
ExprResult Sema::ActOnSizeofParameterPackExpr(Scope *S,
SourceLocation OpLoc,
IdentifierInfo &Name,
SourceLocation NameLoc,
SourceLocation RParenLoc) {
// C++0x [expr.sizeof]p5:
// The identifier in a sizeof... expression shall name a parameter pack.
LookupResult R(*this, &Name, NameLoc, LookupOrdinaryName);
LookupName(R, S);
NamedDecl *ParameterPack = nullptr;
switch (R.getResultKind()) {
case LookupResult::Found:
ParameterPack = R.getFoundDecl();
break;
case LookupResult::NotFound:
case LookupResult::NotFoundInCurrentInstantiation: {
ParameterPackValidatorCCC CCC{};
if (TypoCorrection Corrected =
CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
CCC, CTK_ErrorRecovery)) {
diagnoseTypo(Corrected,
PDiag(diag::err_sizeof_pack_no_pack_name_suggest) << &Name,
PDiag(diag::note_parameter_pack_here));
ParameterPack = Corrected.getCorrectionDecl();
}
break;
}
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
break;
case LookupResult::Ambiguous:
DiagnoseAmbiguousLookup(R);
return ExprError();
}
if (!ParameterPack || !ParameterPack->isParameterPack()) {
Diag(NameLoc, diag::err_sizeof_pack_no_pack_name)
<< &Name;
return ExprError();
}
MarkAnyDeclReferenced(OpLoc, ParameterPack, true);
return SizeOfPackExpr::Create(Context, OpLoc, ParameterPack, NameLoc,
RParenLoc);
}
TemplateArgumentLoc
Sema::getTemplateArgumentPackExpansionPattern(
TemplateArgumentLoc OrigLoc,
SourceLocation &Ellipsis, Optional<unsigned> &NumExpansions) const {
const TemplateArgument &Argument = OrigLoc.getArgument();
assert(Argument.isPackExpansion());
switch (Argument.getKind()) {
case TemplateArgument::Type: {
// FIXME: We shouldn't ever have to worry about missing
// type-source info!
TypeSourceInfo *ExpansionTSInfo = OrigLoc.getTypeSourceInfo();
if (!ExpansionTSInfo)
ExpansionTSInfo = Context.getTrivialTypeSourceInfo(Argument.getAsType(),
Ellipsis);
PackExpansionTypeLoc Expansion =
ExpansionTSInfo->getTypeLoc().castAs<PackExpansionTypeLoc>();
Ellipsis = Expansion.getEllipsisLoc();
TypeLoc Pattern = Expansion.getPatternLoc();
NumExpansions = Expansion.getTypePtr()->getNumExpansions();
// We need to copy the TypeLoc because TemplateArgumentLocs store a
// TypeSourceInfo.
// FIXME: Find some way to avoid the copy?
TypeLocBuilder TLB;
TLB.pushFullCopy(Pattern);
TypeSourceInfo *PatternTSInfo =
TLB.getTypeSourceInfo(Context, Pattern.getType());
return TemplateArgumentLoc(TemplateArgument(Pattern.getType()),
PatternTSInfo);
}
case TemplateArgument::Expression: {
PackExpansionExpr *Expansion
= cast<PackExpansionExpr>(Argument.getAsExpr());
Expr *Pattern = Expansion->getPattern();
Ellipsis = Expansion->getEllipsisLoc();
NumExpansions = Expansion->getNumExpansions();
return TemplateArgumentLoc(Pattern, Pattern);
}
case TemplateArgument::TemplateExpansion:
Ellipsis = OrigLoc.getTemplateEllipsisLoc();
NumExpansions = Argument.getNumTemplateExpansions();
return TemplateArgumentLoc(Argument.getPackExpansionPattern(),
OrigLoc.getTemplateQualifierLoc(),
OrigLoc.getTemplateNameLoc());
case TemplateArgument::Declaration:
case TemplateArgument::NullPtr:
case TemplateArgument::Template:
case TemplateArgument::Integral:
case TemplateArgument::Pack:
case TemplateArgument::Null:
return TemplateArgumentLoc();
}
llvm_unreachable("Invalid TemplateArgument Kind!");
}
Optional<unsigned> Sema::getFullyPackExpandedSize(TemplateArgument Arg) {
assert(Arg.containsUnexpandedParameterPack());
// If this is a substituted pack, grab that pack. If not, we don't know
// the size yet.
// FIXME: We could find a size in more cases by looking for a substituted
// pack anywhere within this argument, but that's not necessary in the common
// case for 'sizeof...(A)' handling.
TemplateArgument Pack;
switch (Arg.getKind()) {
case TemplateArgument::Type:
if (auto *Subst = Arg.getAsType()->getAs<SubstTemplateTypeParmPackType>())
Pack = Subst->getArgumentPack();
else
return None;
break;
case TemplateArgument::Expression:
if (auto *Subst =
dyn_cast<SubstNonTypeTemplateParmPackExpr>(Arg.getAsExpr()))
Pack = Subst->getArgumentPack();
else if (auto *Subst = dyn_cast<FunctionParmPackExpr>(Arg.getAsExpr())) {
for (ParmVarDecl *PD : *Subst)
if (PD->isParameterPack())
return None;
return Subst->getNumExpansions();
} else
return None;
break;
case TemplateArgument::Template:
if (SubstTemplateTemplateParmPackStorage *Subst =
Arg.getAsTemplate().getAsSubstTemplateTemplateParmPack())
Pack = Subst->getArgumentPack();
else
return None;
break;
case TemplateArgument::Declaration:
case TemplateArgument::NullPtr:
case TemplateArgument::TemplateExpansion:
case TemplateArgument::Integral:
case TemplateArgument::Pack:
case TemplateArgument::Null:
return None;
}
// Check that no argument in the pack is itself a pack expansion.
for (TemplateArgument Elem : Pack.pack_elements()) {
// There's no point recursing in this case; we would have already
// expanded this pack expansion into the enclosing pack if we could.
if (Elem.isPackExpansion())
return None;
}
return Pack.pack_size();
}
static void CheckFoldOperand(Sema &S, Expr *E) {
if (!E)
return;
E = E->IgnoreImpCasts();
auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
if ((OCE && OCE->isInfixBinaryOp()) || isa<BinaryOperator>(E) ||
isa<AbstractConditionalOperator>(E)) {
S.Diag(E->getExprLoc(), diag::err_fold_expression_bad_operand)
<< E->getSourceRange()
<< FixItHint::CreateInsertion(E->getBeginLoc(), "(")
<< FixItHint::CreateInsertion(E->getEndLoc(), ")");
}
}
ExprResult Sema::ActOnCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
tok::TokenKind Operator,
SourceLocation EllipsisLoc, Expr *RHS,
SourceLocation RParenLoc) {
// LHS and RHS must be cast-expressions. We allow an arbitrary expression
// in the parser and reduce down to just cast-expressions here.
CheckFoldOperand(*this, LHS);
CheckFoldOperand(*this, RHS);
auto DiscardOperands = [&] {
CorrectDelayedTyposInExpr(LHS);
CorrectDelayedTyposInExpr(RHS);
};
// [expr.prim.fold]p3:
// In a binary fold, op1 and op2 shall be the same fold-operator, and
// either e1 shall contain an unexpanded parameter pack or e2 shall contain
// an unexpanded parameter pack, but not both.
if (LHS && RHS &&
LHS->containsUnexpandedParameterPack() ==
RHS->containsUnexpandedParameterPack()) {
DiscardOperands();
return Diag(EllipsisLoc,
LHS->containsUnexpandedParameterPack()
? diag::err_fold_expression_packs_both_sides
: diag::err_pack_expansion_without_parameter_packs)
<< LHS->getSourceRange() << RHS->getSourceRange();
}
// [expr.prim.fold]p2:
// In a unary fold, the cast-expression shall contain an unexpanded
// parameter pack.
if (!LHS || !RHS) {
Expr *Pack = LHS ? LHS : RHS;
assert(Pack && "fold expression with neither LHS nor RHS");
DiscardOperands();
if (!Pack->containsUnexpandedParameterPack())
return Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
<< Pack->getSourceRange();
}
BinaryOperatorKind Opc = ConvertTokenKindToBinaryOpcode(Operator);
return BuildCXXFoldExpr(LParenLoc, LHS, Opc, EllipsisLoc, RHS, RParenLoc);
}
ExprResult Sema::BuildCXXFoldExpr(SourceLocation LParenLoc, Expr *LHS,
BinaryOperatorKind Operator,
SourceLocation EllipsisLoc, Expr *RHS,
SourceLocation RParenLoc) {
return new (Context) CXXFoldExpr(Context.DependentTy, LParenLoc, LHS,
Operator, EllipsisLoc, RHS, RParenLoc);
}
ExprResult Sema::BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
BinaryOperatorKind Operator) {
// [temp.variadic]p9:
// If N is zero for a unary fold-expression, the value of the expression is
// && -> true
// || -> false
// , -> void()
// if the operator is not listed [above], the instantiation is ill-formed.
//
// Note that we need to use something like int() here, not merely 0, to
// prevent the result from being a null pointer constant.
QualType ScalarType;
switch (Operator) {
case BO_LOr:
return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_false);
case BO_LAnd:
return ActOnCXXBoolLiteral(EllipsisLoc, tok::kw_true);
case BO_Comma:
ScalarType = Context.VoidTy;
break;
default:
return Diag(EllipsisLoc, diag::err_fold_expression_empty)
<< BinaryOperator::getOpcodeStr(Operator);
}
return new (Context) CXXScalarValueInitExpr(
ScalarType, Context.getTrivialTypeSourceInfo(ScalarType, EllipsisLoc),
EllipsisLoc);
}
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