https://github.com/tbaederr updated
https://github.com/llvm/llvm-project/pull/101218
>From 78961fbfbd791844b1622aa305664199e3451260 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Tue, 30 Jul 2024 20:11:37 +0200
Subject: [PATCH] [clang][Interp] Handle virtual calls with covariant return
types
---
clang/lib/AST/Interp/Interp.h | 24 +++++++++++++++++++++++-
clang/test/AST/Interp/cxx2a.cpp | 21 +++++++++++++++++++++
2 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h
index d128988a480e1..63e9966b831db 100644
--- a/clang/lib/AST/Interp/Interp.h
+++ b/clang/lib/AST/Interp/Interp.h
@@ -2628,7 +2628,29 @@ inline bool CallVirt(InterpState &S, CodePtr OpPC, const
Function *Func,
}
}
- return Call(S, OpPC, Func, VarArgSize);
+ if (!Call(S, OpPC, Func, VarArgSize))
+ return false;
+
+ // Covariant return types. The return type of Overrider is a pointer
+ // or reference to a class type.
+ if (Overrider != InitialFunction &&
+ Overrider->getReturnType()->isPointerOrReferenceType() &&
+ InitialFunction->getReturnType()->isPointerOrReferenceType()) {
+ QualType OverriderPointeeType =
+ Overrider->getReturnType()->getPointeeType();
+ QualType InitialPointeeType =
+ InitialFunction->getReturnType()->getPointeeType();
+ // We've called Overrider above, but calling code expects us to return what
+ // InitialFunction returned. According to the rules for covariant return
+ // types, what InitialFunction returns needs to be a base class of what
+ // Overrider returns. So, we need to do an upcast here.
+ unsigned Offset = S.getContext().collectBaseOffset(
+ InitialPointeeType->getAsRecordDecl(),
+ OverriderPointeeType->getAsRecordDecl());
+ return GetPtrBasePop(S, OpPC, Offset);
+ }
+
+ return true;
}
inline bool CallBI(InterpState &S, CodePtr &PC, const Function *Func,
diff --git a/clang/test/AST/Interp/cxx2a.cpp b/clang/test/AST/Interp/cxx2a.cpp
index 27d1aa1a27f75..ad021b30cfd3c 100644
--- a/clang/test/AST/Interp/cxx2a.cpp
+++ b/clang/test/AST/Interp/cxx2a.cpp
@@ -13,3 +13,24 @@ consteval int aConstevalFunction() { // both-error
{{consteval function never pr
return 0;
}
/// We're NOT calling the above function. The diagnostics should appear anyway.
+
+namespace Covariant {
+ struct A {
+ virtual constexpr char f() const { return 'Z'; }
+ char a = f();
+ };
+
+ struct D : A {};
+ struct Covariant1 {
+ D d;
+ virtual const A *f() const;
+ };
+
+ struct Covariant3 : Covariant1 {
+ constexpr virtual const D *f() const { return &this->d; }
+ };
+
+ constexpr Covariant3 cb;
+ constexpr const Covariant1 *cb1 = &cb;
+ static_assert(cb1->f()->a == 'Z');
+}
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