Teach PackExpansionExpr to keep track of the number of pack expansions
it will expand to, if known. Propagate this information throughout Sema.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123470 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index c03a778..fddd14e 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -1463,9 +1463,6 @@
unsigned ArgIdx = 0, ParamIdx = 0;
for (; hasTemplateArgumentForDeduction(Params, ParamIdx, NumParams);
++ParamIdx) {
- // FIXME: Variadic templates.
- // What do we do if the argument is a pack expansion?
-
if (!Params[ParamIdx].isPackExpansion()) {
// The simple case: deduce template arguments by matching Pi and Ai.
diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 899b58e..38a777e 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -415,6 +415,11 @@
}
ExprResult Sema::ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
+ return CheckPackExpansion(Pattern, EllipsisLoc, llvm::Optional<unsigned>());
+}
+
+ExprResult Sema::CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
+ llvm::Optional<unsigned> NumExpansions) {
if (!Pattern)
return ExprError();
@@ -430,7 +435,7 @@
// Create the pack expansion expression and source-location information.
return Owned(new (Context) PackExpansionExpr(Context.DependentTy, Pattern,
- EllipsisLoc));
+ EllipsisLoc, NumExpansions));
}
/// \brief Retrieve the depth and index of a parameter pack.
@@ -459,10 +464,6 @@
std::pair<IdentifierInfo *, SourceLocation> FirstPack;
bool HaveFirstPack = false;
- // FIXME: Variadic templates. Even if we don't expand, we'd still like to
- // return the number of expansions back to the caller, perhaps as an
- // llvm::Optional, so that it can be embedded in the pack expansion. This
- // is important for the multi-level substitution case.
for (unsigned I = 0; I != NumUnexpanded; ++I) {
// Compute the depth and index for this parameter pack.
unsigned Depth;
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index f2496c2..d973f82 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -2176,8 +2176,8 @@
switch (Pattern.getArgument().getKind()) {
case TemplateArgument::Expression: {
ExprResult Result
- = getSema().ActOnPackExpansion(Pattern.getSourceExpression(),
- EllipsisLoc);
+ = getSema().CheckPackExpansion(Pattern.getSourceExpression(),
+ EllipsisLoc, NumExpansions);
if (Result.isInvalid())
return TemplateArgumentLoc();
@@ -2217,8 +2217,9 @@
/// By default, performs semantic analysis to build a new pack expansion
/// for an expression. Subclasses may override this routine to provide
/// different behavior.
- ExprResult RebuildPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc) {
- return getSema().ActOnPackExpansion(Pattern, EllipsisLoc);
+ ExprResult RebuildPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
+ llvm::Optional<unsigned> NumExpansions) {
+ return getSema().CheckPackExpansion(Pattern, EllipsisLoc, NumExpansions);
}
private:
@@ -2308,7 +2309,9 @@
// be expanded.
bool Expand = true;
bool RetainExpansion = false;
- llvm::Optional<unsigned> NumExpansions;
+ llvm::Optional<unsigned> OrigNumExpansions
+ = Expansion->getNumExpansions();
+ llvm::Optional<unsigned> NumExpansions = OrigNumExpansions;
if (getDerived().TryExpandParameterPacks(Expansion->getEllipsisLoc(),
Pattern->getSourceRange(),
Unexpanded.data(),
@@ -2326,9 +2329,9 @@
if (OutPattern.isInvalid())
return true;
- // FIXME: Variadic templates NumExpansions
ExprResult Out = getDerived().RebuildPackExpansion(OutPattern.get(),
- Expansion->getEllipsisLoc());
+ Expansion->getEllipsisLoc(),
+ NumExpansions);
if (Out.isInvalid())
return true;
@@ -2347,7 +2350,8 @@
return true;
if (Out.get()->containsUnexpandedParameterPack()) {
- Out = RebuildPackExpansion(Out.get(), Expansion->getEllipsisLoc());
+ Out = RebuildPackExpansion(Out.get(), Expansion->getEllipsisLoc(),
+ OrigNumExpansions);
if (Out.isInvalid())
return true;
}
@@ -6818,7 +6822,8 @@
if (!getDerived().AlwaysRebuild() && Pattern.get() == E->getPattern())
return SemaRef.Owned(E);
- return getDerived().RebuildPackExpansion(Pattern.get(), E->getEllipsisLoc());
+ return getDerived().RebuildPackExpansion(Pattern.get(), E->getEllipsisLoc(),
+ E->getNumExpansions());
}
template<typename Derived>