SlaterLatiao created this revision.
Herald added a project: All.
SlaterLatiao requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D158006
Files:
clang/include/clang/AST/ExprCXX.h
clang/lib/AST/ComputeDependence.cpp
clang/lib/AST/ExprCXX.cpp
clang/lib/Sema/SemaExprMember.cpp
clang/lib/Sema/SemaTemplateInstantiate.cpp
clang/lib/Sema/TreeTransform.h
clang/test/CodeGenCXX/data_member_packs.cpp
Index: clang/test/CodeGenCXX/data_member_packs.cpp
===================================================================
--- clang/test/CodeGenCXX/data_member_packs.cpp
+++ clang/test/CodeGenCXX/data_member_packs.cpp
@@ -10,6 +10,11 @@
Ts... ts;
};
+template<typename T, typename... Ts> struct S3 {
+ T t;
+ Ts... ts;
+};
+
// CHECK: %struct.S1 = type { i32 }
S1<int> s1;
// CHECK-NEXT: %struct.S1.0 = type { i32, float, double }
@@ -28,3 +33,47 @@
// CHECK-NEXT: %struct.S1.4 = type { i32, i32 }
S1<int, int> s6;
+S1<int, long, float, double> s7;
+
+template<typename... Ts> auto sum(Ts... ts) {
+ return (ts + ...);
+}
+
+auto take_empty() {
+ return 0;
+}
+
+template<typename... Ts> auto sum_pack(S1<Ts...> s) {
+ return sum(s.ts...);
+}
+// Test template arg + expansion.
+template<typename T, typename... Ts> auto sum_pack2(S1<T, Ts...> s) {
+ return sum(s.ts...);
+}
+// Test empty expansion.
+template<typename... Ts> auto take_empty(S3<Ts...> s) {
+ return take_empty(s.ts...);
+}
+// Test nested template args and multiple expansions.
+template<typename... Ts> struct S4 {
+ template<typename... Ts2> auto sum_pack(S1<Ts..., Ts2...> s) {
+ return sum(s.ts...);
+ }
+};
+
+int main() {
+ // Check calling take_empty()
+ // CHECK: %call = call noundef i32 @_Z10take_emptyv()
+ take_empty(S3<int>{});
+ // Check instantiation of sum(int, float, double)
+ // CHECK: double @_Z3sumIJifdEEDaDpT_(i32 noundef %ts, float noundef %ts1, double noundef %ts3)
+ sum_pack(s2);
+ // Check instantiation of sum(int, int)
+ // CHECK: i32 @_Z3sumIJiiEEDaDpT_(i32 noundef %ts, i32 noundef %ts1)
+ sum_pack2<int, int>(s6);
+ // Check instantiation of sum(int, long, float, double)
+ // CHECK: double @_Z3sumIJilfdEEDaDpT_(i32 noundef %ts, i64 noundef %ts1, float noundef %ts3, double noundef %ts5)
+ S4<int, long>{}.sum_pack<float, double>(s7);
+ return 0;
+}
+
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -4168,6 +4168,58 @@
if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(Inputs[I])) {
Expr *Pattern = Expansion->getPattern();
+ if (CXXDependentScopeMemberExpr *MemberExpr =
+ dyn_cast<CXXDependentScopeMemberExpr>(Pattern)) {
+ if (ArgChanged)
+ *ArgChanged = true;
+ assert(MemberExpr->isMemberPackAccess() &&
+ "trying to expand non-pack member access");
+ std::string UnExpanedNameStr =
+ MemberExpr->getMemberNameInfo().getName().getAsString();
+
+ ExprResult Base = getDerived().TransformExpr(MemberExpr->getBase());
+ if (Base.isInvalid())
+ return true;
+ QualType BaseType = ((Expr *)Base.get())->getType();
+ if (MemberExpr->isArrow()) {
+ assert(BaseType->isPointerType());
+ BaseType = BaseType->castAs<PointerType>()->getPointeeType();
+ }
+
+ unsigned Arg = 0;
+ while (true) {
+ // Transform unexpanded field name and create a new member expression.
+ DeclarationName ExpandedName = &SemaRef.Context.Idents.get(
+ UnExpanedNameStr + "@" + std::to_string(Arg));
+ // Construct name info with new name and keep other members the same.
+ DeclarationNameInfo ExpandedNameInfo = DeclarationNameInfo(
+ ExpandedName, MemberExpr->getMemberNameInfo().getLoc(),
+ MemberExpr->getMemberNameInfo().getInfo());
+ TemplateArgumentListInfo TemplateArgs = TemplateArgumentListInfo();
+ MemberExpr->copyTemplateArgumentsInto(TemplateArgs);
+ auto *ExpandedMemberExpr = CXXDependentScopeMemberExpr::Create(
+ SemaRef.Context, MemberExpr->getBase(), MemberExpr->getBaseType(),
+ MemberExpr->isArrow(), MemberExpr->getOperatorLoc(),
+ MemberExpr->getQualifierLoc(),
+ MemberExpr->getTemplateKeywordLoc(),
+ MemberExpr->getFirstQualifierFoundInScope(), ExpandedNameInfo,
+ &TemplateArgs, MemberExpr->isMemberPackAccess());
+
+ Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(getSema(), Arg);
+ ExprResult Out = getDerived().TransformExpr(ExpandedMemberExpr);
+ if (Out.isInvalid())
+ return true;
+ // An empty expression is returned when name lookup fails in accessing
+ // member packs. This means the last field in member pack has been
+ // processd and time to exit the loop.
+ if (Out.isUnset())
+ break;
+ Outputs.push_back(Out.get());
+ Arg++;
+ }
+ continue;
+ }
+
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
getSema().collectUnexpandedParameterPacks(Pattern, Unexpanded);
assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");
Index: clang/lib/Sema/SemaTemplateInstantiate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -3285,6 +3285,12 @@
SubstType(PatternType, TemplateArgs, PackedField->getLocation(),
PackedField->getDeclName());
PackedField->setType(T);
+ // Rename the expanded fields to avoid ambiguous names in
+ // name lookup. The renamed fields need to be invisible to users so an
+ // `@` is added to the name.
+ std::string NewFieldName =
+ PackedField->getName().str() + "@" + std::to_string(Arg);
+ PackedField->setDeclName(&Context.Idents.get(NewFieldName));
Fields.push_back(PackedField);
if (NewMember->isInvalidDecl()) {
// When `NewMember` has type of `PackExpansionType`, it escapes
Index: clang/lib/Sema/SemaExprMember.cpp
===================================================================
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -514,12 +514,32 @@
return Arg.getArgument().isDependent();
})));
- // Get the type being accessed in BaseType. If this is an arrow, the BaseExpr
+ bool isMemberPack = false;
+ // Check for member packs by looking up base's template decl.
+ if (const ElaboratedType *ET = dyn_cast<const ElaboratedType>(BaseType)) {
+ if (const TemplateSpecializationType *TST =
+ dyn_cast<TemplateSpecializationType>(ET->getNamedType())) {
+ auto *TD = TST->getTemplateName().getAsTemplateDecl();
+ assert(isa<ClassTemplateDecl>(TD) &&
+ "template decl in member access is not ClassTemplateDecl");
+ for (FieldDecl *Field :
+ cast<ClassTemplateDecl>(TD)->getTemplatedDecl()->fields()) {
+ if (Field->getDeclName() == NameInfo.getName()) {
+ if (const PackExpansionType *PET =
+ dyn_cast<PackExpansionType>(Field->getType())) {
+ isMemberPack = true;
+ }
+ break;
+ }
+ }
+ }
+ }
+ // Get the type being accessed in BaseType. If this is an arrow, the BaseExpr
// must have pointer type, and the accessed type is the pointee.
return CXXDependentScopeMemberExpr::Create(
Context, BaseExpr, BaseType, IsArrow, OpLoc,
SS.getWithLocInContext(Context), TemplateKWLoc, FirstQualifierInScope,
- NameInfo, TemplateArgs);
+ NameInfo, TemplateArgs, isMemberPack);
}
/// We know that the given qualified member reference points only to
@@ -995,10 +1015,17 @@
<< isa<CXXDestructorDecl>(FD);
if (R.empty()) {
+ // The member is expaned from member pack if its name has `@` in it. In this
+ // case a failed name lookup is not an error, but represents it's at the end
+ // of the expanded members. Return an empty expression to inform its
+ // caller.
+ auto MemberNameStr = MemberNameInfo.getName().getAsString();
+ if (MemberNameStr.find('@') != std::string::npos) {
+ return ExprEmpty();
+ }
// Rederive where we looked up.
- DeclContext *DC = (SS.isSet()
- ? computeDeclContext(SS, false)
- : BaseType->castAs<RecordType>()->getDecl());
+ DeclContext *DC = (SS.isSet() ? computeDeclContext(SS, false)
+ : BaseType->castAs<RecordType>()->getDecl());
if (ExtraArgs) {
ExprResult RetryExpr;
Index: clang/lib/AST/ExprCXX.cpp
===================================================================
--- clang/lib/AST/ExprCXX.cpp
+++ clang/lib/AST/ExprCXX.cpp
@@ -1443,11 +1443,11 @@
SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
DeclarationNameInfo MemberNameInfo,
- const TemplateArgumentListInfo *TemplateArgs)
+ const TemplateArgumentListInfo *TemplateArgs, bool isMemberPack)
: Expr(CXXDependentScopeMemberExprClass, Ctx.DependentTy, VK_LValue,
OK_Ordinary),
Base(Base), BaseType(BaseType), QualifierLoc(QualifierLoc),
- MemberNameInfo(MemberNameInfo) {
+ MemberNameInfo(MemberNameInfo), isMemberPack(isMemberPack) {
CXXDependentScopeMemberExprBits.IsArrow = IsArrow;
CXXDependentScopeMemberExprBits.HasTemplateKWAndArgsInfo =
(TemplateArgs != nullptr) || TemplateKWLoc.isValid();
@@ -1478,6 +1478,7 @@
HasTemplateKWAndArgsInfo;
CXXDependentScopeMemberExprBits.HasFirstQualifierFoundInScope =
HasFirstQualifierFoundInScope;
+ isMemberPack = false;
}
CXXDependentScopeMemberExpr *CXXDependentScopeMemberExpr::Create(
@@ -1485,7 +1486,8 @@
SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
DeclarationNameInfo MemberNameInfo,
- const TemplateArgumentListInfo *TemplateArgs) {
+ const TemplateArgumentListInfo *TemplateArgs,
+ bool isMemberPack) {
bool HasTemplateKWAndArgsInfo =
(TemplateArgs != nullptr) || TemplateKWLoc.isValid();
unsigned NumTemplateArgs = TemplateArgs ? TemplateArgs->size() : 0;
@@ -1498,7 +1500,7 @@
void *Mem = Ctx.Allocate(Size, alignof(CXXDependentScopeMemberExpr));
return new (Mem) CXXDependentScopeMemberExpr(
Ctx, Base, BaseType, IsArrow, OperatorLoc, QualifierLoc, TemplateKWLoc,
- FirstQualifierFoundInScope, MemberNameInfo, TemplateArgs);
+ FirstQualifierFoundInScope, MemberNameInfo, TemplateArgs, isMemberPack);
}
CXXDependentScopeMemberExpr *CXXDependentScopeMemberExpr::CreateEmpty(
Index: clang/lib/AST/ComputeDependence.cpp
===================================================================
--- clang/lib/AST/ComputeDependence.cpp
+++ clang/lib/AST/ComputeDependence.cpp
@@ -826,6 +826,8 @@
D |= getDependenceInExpr(E->getMemberNameInfo());
for (const auto &A : E->template_arguments())
D |= toExprDependence(A.getArgument().getDependence());
+ if (E->isMemberPackAccess())
+ D |= ExprDependence::UnexpandedPack;
return D;
}
Index: clang/include/clang/AST/ExprCXX.h
===================================================================
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -3658,6 +3658,9 @@
/// FIXME: could also be a template-id
DeclarationNameInfo MemberNameInfo;
+ /// Whether the member is a member pack.
+ bool isMemberPack;
+
// CXXDependentScopeMemberExpr is followed by several trailing objects,
// some of which optional. They are in order:
//
@@ -3693,14 +3696,12 @@
return hasFirstQualifierFoundInScope();
}
- CXXDependentScopeMemberExpr(const ASTContext &Ctx, Expr *Base,
- QualType BaseType, bool IsArrow,
- SourceLocation OperatorLoc,
- NestedNameSpecifierLoc QualifierLoc,
- SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierFoundInScope,
- DeclarationNameInfo MemberNameInfo,
- const TemplateArgumentListInfo *TemplateArgs);
+ CXXDependentScopeMemberExpr(
+ const ASTContext &Ctx, Expr *Base, QualType BaseType, bool IsArrow,
+ SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
+ SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
+ DeclarationNameInfo MemberNameInfo,
+ const TemplateArgumentListInfo *TemplateArgs, bool isMemberPack);
CXXDependentScopeMemberExpr(EmptyShell Empty, bool HasTemplateKWAndArgsInfo,
bool HasFirstQualifierFoundInScope);
@@ -3711,7 +3712,8 @@
SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
DeclarationNameInfo MemberNameInfo,
- const TemplateArgumentListInfo *TemplateArgs);
+ const TemplateArgumentListInfo *TemplateArgs,
+ bool isMemberPack = false);
static CXXDependentScopeMemberExpr *
CreateEmpty(const ASTContext &Ctx, bool HasTemplateKWAndArgsInfo,
@@ -3735,6 +3737,8 @@
QualType getBaseType() const { return BaseType; }
+ bool isMemberPackAccess() const { return isMemberPack; }
+
/// Determine whether this member expression used the '->'
/// operator; otherwise, it used the '.' operator.
bool isArrow() const { return CXXDependentScopeMemberExprBits.IsArrow; }
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