[clang] [clang][Interp] Handle CXXScalarValueInitExprs (PR #67147)

[Timm Baeder via cfe-commits]

Timm =?utf-8?q?Bäder?= <tbaeder at redhat.com>
Message-ID:
In-Reply-To: <llvm/llvm-project/pull/67147/clang at github.com>


https://github.com/tbaederr updated https://github.com/llvm/llvm-project/pull/67147

>From 9c0cc7fde8473c9b02733720149343c4b2dcddae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Sat, 23 Sep 2023 11:41:52 +0200
Subject: [PATCH 1/2] [clang][Interp] Fix returning nullptr from functions

isLive() is false for null pointers, so we need to special-case
this here.
---
 clang/lib/AST/Interp/Interp.h       | 2 +-
 clang/test/AST/Interp/functions.cpp | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h
index 8453856e526a6b2..71d49a0894f4e35 100644
--- a/clang/lib/AST/Interp/Interp.h
+++ b/clang/lib/AST/Interp/Interp.h
@@ -209,7 +209,7 @@ bool Ret(InterpState &S, CodePtr &PC, APValue &Result) {
     // FIXME: We could be calling isLive() here, but the emitted diagnostics
     // seem a little weird, at least if the returned expression is of
     // pointer type.
-    if (!Ret.isLive())
+    if (!Ret.isZero() && !Ret.isLive())
       return false;
   }
 
diff --git a/clang/test/AST/Interp/functions.cpp b/clang/test/AST/Interp/functions.cpp
index 331df74d50b3d62..7f03271d152db5c 100644
--- a/clang/test/AST/Interp/functions.cpp
+++ b/clang/test/AST/Interp/functions.cpp
@@ -332,3 +332,10 @@ namespace InvalidReclRefs {
   }
 #endif
 }
+
+namespace PtrReturn {
+  constexpr void *a() {
+    return nullptr;
+  }
+  static_assert(a() == nullptr, "");
+}

>From 1ab2489cac860395074a7e537dd3a48e09781d26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Fri, 22 Sep 2023 16:27:11 +0200
Subject: [PATCH 2/2] [clang][Interp] Handle CXXScalarValueInitExprs

---
 clang/lib/AST/Interp/ByteCodeExprGen.cpp |  6 ++++++
 clang/lib/AST/Interp/ByteCodeExprGen.h   |  1 +
 clang/test/AST/Interp/literals.cpp       | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index e813d4fa651ceaf..c804bab7ce567d0 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1488,6 +1488,12 @@ bool ByteCodeExprGen<Emitter>::VisitOffsetOfExpr(const OffsetOfExpr *E) {
   return this->emitOffsetOf(T, E, E);
 }
 
+template <class Emitter>
+bool ByteCodeExprGen<Emitter>::VisitCXXScalarValueInitExpr(
+    const CXXScalarValueInitExpr *E) {
+  return this->visitZeroInitializer(E->getType(), E);
+}
+
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
   if (E->containsErrors())
     return false;
diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.h b/clang/lib/AST/Interp/ByteCodeExprGen.h
index 47a3f75f13459d0..7cfe4d9251c5f05 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.h
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.h
@@ -106,6 +106,7 @@ class ByteCodeExprGen : public ConstStmtVisitor<ByteCodeExprGen<Emitter>, bool>,
   bool VisitCXXConstructExpr(const CXXConstructExpr *E);
   bool VisitSourceLocExpr(const SourceLocExpr *E);
   bool VisitOffsetOfExpr(const OffsetOfExpr *E);
+  bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E);
 
 protected:
   bool visitExpr(const Expr *E) override;
diff --git a/clang/test/AST/Interp/literals.cpp b/clang/test/AST/Interp/literals.cpp
index aabc909b3328e48..39a9ff73bef5e08 100644
--- a/clang/test/AST/Interp/literals.cpp
+++ b/clang/test/AST/Interp/literals.cpp
@@ -31,6 +31,28 @@ static_assert(b, "");
 constexpr int one = true;
 static_assert(one == 1, "");
 
+constexpr bool b2 = bool();
+static_assert(!b2, "");
+
+namespace ScalarTypes {
+  constexpr int ScalarInitInt = int();
+  static_assert(ScalarInitInt == 0, "");
+  constexpr float ScalarInitFloat = float();
+  static_assert(ScalarInitFloat == 0.0f, "");
+
+  static_assert(decltype(nullptr)() == nullptr, "");
+
+  template<typename T>
+  constexpr T getScalar() { return T(); }
+
+  static_assert(getScalar<const int>() == 0, "");
+  static_assert(getScalar<const double>() == 0.0, "");
+
+  static_assert(getScalar<void*>() == nullptr, "");
+  static_assert(getScalar<void(*)(void)>() == nullptr, "");
+  /// FIXME: Member pointers.
+}
+
 namespace IntegralCasts {
   constexpr int i = 12;
   constexpr unsigned int ui = i;