From 211b51e4713d814d6fa894f4fc309a364c5642ce Mon Sep 17 00:00:00 2001
From: Timm Baeder <tbaeder@redhat.com>
Date: Fri, 25 Apr 2025 11:23:34 +0200
Subject: [clang][bytecode] Propagate IsVolatile bit to subobjects (#137293)

For
```c++
  struct S {
    constexpr S(int=0) : i(1) {}
    int i;
  };
  constexpr volatile S vs;
```

reading from `vs.i` is not allowed, even though `i` is not volatile
qualified. Propagate the IsVolatile bit down the hierarchy, so we know
reading from `vs.i` is a volatile read.
---
 clang/lib/AST/ByteCode/Compiler.cpp | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

(limited to 'clang/lib/AST/ByteCode/Compiler.cpp')

diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 65d87cd..3c774c1 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -364,8 +364,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
         Desc = P.createDescriptor(SubExpr, *T);
       else
         Desc = P.createDescriptor(SubExpr, PointeeType.getTypePtr(),
-                                  std::nullopt, true, false,
-                                  /*IsMutable=*/false, nullptr);
+                                  std::nullopt, /*IsConst=*/true);
     }
 
     uint64_t Val = Ctx.getASTContext().getTargetNullPointerValue(CE->getType());
@@ -417,8 +416,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
       Desc = nullptr;
     else
       Desc = P.createDescriptor(CE, PtrType->getPointeeType().getTypePtr(),
-                                Descriptor::InlineDescMD, true, false,
-                                /*IsMutable=*/false, nullptr);
+                                Descriptor::InlineDescMD, /*IsConst=*/true);
 
     if (!this->emitGetIntPtr(T, Desc, CE))
       return false;
@@ -3400,14 +3398,13 @@ bool Compiler<Emitter>::VisitCXXNewExpr(const CXXNewExpr *E) {
         Desc = nullptr; // We're not going to use it in this case.
       else
         Desc = P.createDescriptor(E, *ElemT, /*SourceTy=*/nullptr,
-                                  Descriptor::InlineDescMD,
-                                  /*IsConst=*/false, /*IsTemporary=*/false,
-                                  /*IsMutable=*/false);
+                                  Descriptor::InlineDescMD);
     } else {
       Desc = P.createDescriptor(
           E, ElementType.getTypePtr(),
           E->isArray() ? std::nullopt : Descriptor::InlineDescMD,
-          /*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false, Init);
+          /*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false,
+          /*IsVolatile=*/false, Init);
     }
   }
 
@@ -4355,7 +4352,7 @@ Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
 
   Descriptor *D = P.createDescriptor(
       Src, Ty.getTypePtr(), Descriptor::InlineDescMD, Ty.isConstQualified(),
-      IsTemporary, /*IsMutable=*/false, Init);
+      IsTemporary, /*IsMutable=*/false, /*IsVolatile=*/false, Init);
   if (!D)
     return std::nullopt;
   D->IsConstexprUnknown = IsConstexprUnknown;
@@ -4377,7 +4374,7 @@ std::optional<unsigned> Compiler<Emitter>::allocateTemporary(const Expr *E) {
 
   Descriptor *D = P.createDescriptor(
       E, Ty.getTypePtr(), Descriptor::InlineDescMD, Ty.isConstQualified(),
-      /*IsTemporary=*/true, /*IsMutable=*/false, /*Init=*/nullptr);
+      /*IsTemporary=*/true);
 
   if (!D)
     return std::nullopt;
-- 
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