https://github.com/zyn0217 updated
https://github.com/llvm/llvm-project/pull/112896
>From 6caf16d6ce8eb939c91ed87493c2ccab82d38411 Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7...@gmail.com>
Date: Fri, 18 Oct 2024 20:22:08 +0800
Subject: [PATCH 1/2] [Clang] Don't assert on substituted-but-yet-expanded
packs for nested lambdas
---
clang/docs/ReleaseNotes.rst | 2 +-
clang/lib/Sema/SemaTemplateVariadic.cpp | 49 ++++++++++++++------
clang/test/SemaCXX/lambda-pack-expansion.cpp | 40 ++++++++++++++++
3 files changed, 75 insertions(+), 16 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b430b2b0ee3187..d071c480f36dc7 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -486,7 +486,7 @@ Bug Fixes to C++ Support
- Clang no longer tries to capture non-odr used default arguments of template
parameters of generic lambdas (#GH107048)
- Fixed a bug where defaulted comparison operators would remove ``const`` from
base classes. (#GH102588)
- Fix a crash when using ``source_location`` in the trailing return type of a
lambda expression. (#GH67134)
-- A follow-up fix was added for (#GH61460), as the previous fix was not
entirely correct. (#GH86361)
+- A follow-up fix was added for (#GH61460), as the previous fix was not
entirely correct. (#GH86361), (#GH112352)
- Fixed a crash in the typo correction of an invalid CTAD guide. (#GH107887)
- Fixed a crash when clang tries to subtitute parameter pack while retaining
the parameter
pack. (#GH63819), (#GH107560)
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp
b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 19bd4547665835..151b328872bd75 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -41,7 +41,7 @@ namespace {
unsigned DepthLimit = (unsigned)-1;
#ifndef NDEBUG
- bool ContainsFunctionParmPackExpr = false;
+ bool ContainsIntermediatePacks = false;
#endif
void addUnexpanded(NamedDecl *ND, SourceLocation Loc = SourceLocation()) {
@@ -114,6 +114,11 @@ namespace {
addUnexpanded(TTP);
}
+#ifndef NDEBUG
+ ContainsIntermediatePacks |=
+ (bool)Template.getAsSubstTemplateTemplateParmPack();
+#endif
+
return inherited::TraverseTemplateName(Template);
}
@@ -297,13 +302,28 @@ namespace {
#ifndef NDEBUG
bool TraverseFunctionParmPackExpr(FunctionParmPackExpr *) {
- ContainsFunctionParmPackExpr = true;
+ ContainsIntermediatePacks = true;
+ return true;
+ }
+
+ bool TraverseSubstNonTypeTemplateParmPackExpr(
+ SubstNonTypeTemplateParmPackExpr *) {
+ ContainsIntermediatePacks = true;
+ return true;
+ }
+
+ bool VisitSubstTemplateTypeParmPackType(SubstTemplateTypeParmPackType *) {
+ ContainsIntermediatePacks = true;
return true;
}
- bool containsFunctionParmPackExpr() const {
- return ContainsFunctionParmPackExpr;
+ bool
+ VisitSubstTemplateTypeParmPackTypeLoc(SubstTemplateTypeParmPackTypeLoc) {
+ ContainsIntermediatePacks = true;
+ return true;
}
+
+ bool containsIntermediatePacks() const { return ContainsIntermediatePacks;
}
#endif
};
}
@@ -439,21 +459,20 @@ bool Sema::DiagnoseUnexpandedParameterPack(Expr *E,
if (!E->containsUnexpandedParameterPack())
return false;
- // FunctionParmPackExprs are special:
- //
- // 1) they're used to model DeclRefExprs to packs that have been expanded but
- // had that expansion held off in the process of transformation.
- //
- // 2) they always have the unexpanded dependencies but don't introduce new
- // unexpanded packs.
- //
- // We might encounter a FunctionParmPackExpr being a full expression, which a
- // larger CXXFoldExpr would expand.
SmallVector<UnexpandedParameterPack, 2> Unexpanded;
CollectUnexpandedParameterPacksVisitor Visitor(Unexpanded);
Visitor.TraverseStmt(E);
- assert((!Unexpanded.empty() || Visitor.containsFunctionParmPackExpr()) &&
+#ifndef NDEBUG
+ // The expression might contain a type/subexpression that has been
substituted
+ // but has the expansion held off, e.g. a FunctionParmPackExpr which a larger
+ // CXXFoldExpr would expand. It's only possible when expanding a lambda as a
+ // pattern of a fold expression, so don't fire on an empty result in that
+ // case.
+ bool LambdaReferencingOuterPacks =
+ getEnclosingLambdaOrBlock() && Visitor.containsIntermediatePacks();
+ assert((!Unexpanded.empty() || LambdaReferencingOuterPacks) &&
"Unable to find unexpanded parameter packs");
+#endif
return DiagnoseUnexpandedParameterPacks(E->getBeginLoc(), UPPC, Unexpanded);
}
diff --git a/clang/test/SemaCXX/lambda-pack-expansion.cpp
b/clang/test/SemaCXX/lambda-pack-expansion.cpp
index 0e60ecd8756600..7f7dd3bb095d57 100644
--- a/clang/test/SemaCXX/lambda-pack-expansion.cpp
+++ b/clang/test/SemaCXX/lambda-pack-expansion.cpp
@@ -94,3 +94,43 @@ template <typename... Ts> void g2(Ts... p1s) {
void f1() { g(); }
} // namespace GH61460
+
+namespace GH112352 {
+
+template <class>
+constexpr bool foo = false;
+
+template <int>
+constexpr bool bar = false;
+
+template <template<class> class>
+constexpr bool baz = false;
+
+struct S {
+ template <typename... Types, int... Values> void foldExpr1() {
+ (void)[]<int... Is> {
+ ([] {
+ Is;
+ foo<Types>;
+ bar<Values>;
+ } &&
+ ...);
+ };
+ }
+
+ template <template<class> class... TTPs> void foldExpr2() {
+ (void)[]<int... Is> {
+ ([] {
+ Is;
+ baz<TTPs>;
+ } && ...);
+ };
+ }
+};
+
+void use() {
+ S().foldExpr1();
+ S().foldExpr2();
+}
+
+} // namespace GH112352
>From c2d5cc751b37c4aa6f5472e17906bd4eee3723c7 Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7...@gmail.com>
Date: Fri, 18 Oct 2024 21:14:56 +0800
Subject: [PATCH 2/2] Propagate up ContainsUnexpandedParameterPack for VarDecls
---
clang/lib/Sema/TreeTransform.h | 21 ++++++++++++--------
clang/test/SemaCXX/lambda-pack-expansion.cpp | 2 ++
2 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 45e8b3cf6bd8fc..ca04fb7f71be00 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -8385,14 +8385,19 @@ TreeTransform<Derived>::TransformDeclStmt(DeclStmt *S) {
if (Transformed != D)
DeclChanged = true;
- if (LSI && isa<TypeDecl>(Transformed))
- LSI->ContainsUnexpandedParameterPack |=
- getSema()
- .getASTContext()
- .getTypeDeclType(cast<TypeDecl>(Transformed))
- .getCanonicalType()
- .getTypePtr()
- ->containsUnexpandedParameterPack();
+ if (LSI) {
+ if (auto *TD = dyn_cast<TypeDecl>(Transformed))
+ LSI->ContainsUnexpandedParameterPack |=
+ getSema()
+ .getASTContext()
+ .getTypeDeclType(TD)
+ .getCanonicalType()
+ ->containsUnexpandedParameterPack();
+
+ if (auto *VD = dyn_cast<VarDecl>(Transformed))
+ LSI->ContainsUnexpandedParameterPack |=
+ VD->getType()->containsUnexpandedParameterPack();
+ }
Decls.push_back(Transformed);
}
diff --git a/clang/test/SemaCXX/lambda-pack-expansion.cpp
b/clang/test/SemaCXX/lambda-pack-expansion.cpp
index 7f7dd3bb095d57..3d724c5e4d168b 100644
--- a/clang/test/SemaCXX/lambda-pack-expansion.cpp
+++ b/clang/test/SemaCXX/lambda-pack-expansion.cpp
@@ -111,6 +111,8 @@ struct S {
(void)[]<int... Is> {
([] {
Is;
+ // Propagate up the flag ContainsUnexpandedParameterPack from VarDecl.
+ S var(foo<Types>);
foo<Types>;
bar<Values>;
} &&
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