[c++20] P0780R2: Support pack-expansion of init-captures.
This permits an init-capture to introduce a new pack:
template<typename ...T> auto x = [...a = T()] { /* a is a pack */ };
To support this, the mechanism for allowing ParmVarDecls to be packs has
been extended to support arbitrary local VarDecls.
llvm-svn: 361300
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 55d1d94..ba54d50 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -819,7 +819,19 @@
SemaRef.InstantiateAttrs(TemplateArgs, Old, New);
}
- void transformedLocalDecl(Decl *Old, Decl *New) {
+ void transformedLocalDecl(Decl *Old, ArrayRef<Decl *> NewDecls) {
+ if (Old->isParameterPack()) {
+ SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Old);
+ for (auto *New : NewDecls)
+ SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(
+ Old, cast<VarDecl>(New));
+ return;
+ }
+
+ assert(NewDecls.size() == 1 &&
+ "should only have multiple expansions for a pack");
+ Decl *New = NewDecls.front();
+
// If we've instantiated the call operator of a lambda or the call
// operator template of a generic lambda, update the "instantiation of"
// information.
@@ -888,12 +900,11 @@
ExprResult TransformSubstNonTypeTemplateParmPackExpr(
SubstNonTypeTemplateParmPackExpr *E);
- /// Rebuild a DeclRefExpr for a ParmVarDecl reference.
- ExprResult RebuildParmVarDeclRefExpr(ParmVarDecl *PD, SourceLocation Loc);
+ /// Rebuild a DeclRefExpr for a VarDecl reference.
+ ExprResult RebuildVarDeclRefExpr(VarDecl *PD, SourceLocation Loc);
- /// Transform a reference to a function parameter pack.
- ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E,
- ParmVarDecl *PD);
+ /// Transform a reference to a function or init-capture parameter pack.
+ ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E, VarDecl *PD);
/// Transform a FunctionParmPackExpr which was built when we couldn't
/// expand a function parameter pack reference which refers to an expanded
@@ -1324,9 +1335,8 @@
Arg);
}
-ExprResult
-TemplateInstantiator::RebuildParmVarDeclRefExpr(ParmVarDecl *PD,
- SourceLocation Loc) {
+ExprResult TemplateInstantiator::RebuildVarDeclRefExpr(VarDecl *PD,
+ SourceLocation Loc) {
DeclarationNameInfo NameInfo(PD->getDeclName(), Loc);
return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD);
}
@@ -1335,11 +1345,11 @@
TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex != -1) {
// We can expand this parameter pack now.
- ParmVarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
- ValueDecl *VD = cast_or_null<ValueDecl>(TransformDecl(E->getExprLoc(), D));
+ VarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
+ VarDecl *VD = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), D));
if (!VD)
return ExprError();
- return RebuildParmVarDeclRefExpr(cast<ParmVarDecl>(VD), E->getExprLoc());
+ return RebuildVarDeclRefExpr(VD, E->getExprLoc());
}
QualType T = TransformType(E->getType());
@@ -1348,25 +1358,24 @@
// Transform each of the parameter expansions into the corresponding
// parameters in the instantiation of the function decl.
- SmallVector<ParmVarDecl *, 8> Parms;
- Parms.reserve(E->getNumExpansions());
+ SmallVector<VarDecl *, 8> Vars;
+ Vars.reserve(E->getNumExpansions());
for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end();
I != End; ++I) {
- ParmVarDecl *D =
- cast_or_null<ParmVarDecl>(TransformDecl(E->getExprLoc(), *I));
+ VarDecl *D = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), *I));
if (!D)
return ExprError();
- Parms.push_back(D);
+ Vars.push_back(D);
}
return FunctionParmPackExpr::Create(getSema().Context, T,
E->getParameterPack(),
- E->getParameterPackLocation(), Parms);
+ E->getParameterPackLocation(), Vars);
}
ExprResult
TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E,
- ParmVarDecl *PD) {
+ VarDecl *PD) {
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
= getSema().CurrentInstantiationScope->findInstantiationOf(PD);
@@ -1390,8 +1399,7 @@
}
// We have either an unexpanded pack or a specific expansion.
- return RebuildParmVarDeclRefExpr(cast<ParmVarDecl>(TransformedDecl),
- E->getExprLoc());
+ return RebuildVarDeclRefExpr(cast<VarDecl>(TransformedDecl), E->getExprLoc());
}
ExprResult
@@ -1409,7 +1417,7 @@
}
// Handle references to function parameter packs.
- if (ParmVarDecl *PD = dyn_cast<ParmVarDecl>(D))
+ if (VarDecl *PD = dyn_cast<VarDecl>(D))
if (PD->isParameterPack())
return TransformFunctionParmPackRefExpr(E, PD);
@@ -2984,14 +2992,14 @@
#endif
Stored = Inst;
} else if (DeclArgumentPack *Pack = Stored.dyn_cast<DeclArgumentPack *>()) {
- Pack->push_back(cast<ParmVarDecl>(Inst));
+ Pack->push_back(cast<VarDecl>(Inst));
} else {
assert(Stored.get<Decl *>() == Inst && "Already instantiated this local");
}
}
void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D,
- ParmVarDecl *Inst) {
+ VarDecl *Inst) {
D = getCanonicalParmVarDecl(D);
DeclArgumentPack *Pack = LocalDecls[D].get<DeclArgumentPack *>();
Pack->push_back(Inst);