[clang][bytecode] Explicit composite array descriptor types

clang/lib/AST/ByteCode/Descriptor.cpp

@@ -367,10 +367,12 @@ Descriptor::Descriptor(const DeclTy &D, PrimType Type, MetadataSize MD,
 }
 
 /// Arrays of composite elements.
-Descriptor::Descriptor(const DeclTy &D, const Descriptor *Elem, MetadataSize MD,
+Descriptor::Descriptor(const DeclTy &D, const Type *SourceTy,
+                       const Descriptor *Elem, MetadataSize MD,
                        unsigned NumElems, bool IsConst, bool IsTemporary,
                        bool IsMutable)
-    : Source(D), ElemSize(Elem->getAllocSize() + sizeof(InlineDescriptor)),
+    : Source(D), SourceType(SourceTy),
+      ElemSize(Elem->getAllocSize() + sizeof(InlineDescriptor)),
       Size(ElemSize * NumElems), MDSize(MD.value_or(0)),
       AllocSize(std::max<size_t>(alignof(void *), Size) + MDSize),
       ElemDesc(Elem), IsConst(IsConst), IsMutable(IsMutable),
@@ -410,6 +412,8 @@ Descriptor::Descriptor(const DeclTy &D)
 }
 
 QualType Descriptor::getType() const {
+  if (SourceType)
+    return QualType(SourceType, 0);
   if (const auto *D = asValueDecl())
     return D->getType();
   if (const auto *T = dyn_cast_if_present<TypeDecl>(asDecl()))

clang/lib/AST/ByteCode/Descriptor.h

@@ -124,6 +124,7 @@ struct Descriptor final {
 private:
   /// Original declaration, used to emit the error message.
   const DeclTy Source;
+  const Type *SourceType = nullptr;
   /// Size of an element, in host bytes.
   const unsigned ElemSize;
   /// Size of the storage, in host bytes.
@@ -186,8 +187,9 @@ struct Descriptor final {
              bool IsTemporary, UnknownSize);
 
   /// Allocates a descriptor for an array of composites.
-  Descriptor(const DeclTy &D, const Descriptor *Elem, MetadataSize MD,
-             unsigned NumElems, bool IsConst, bool IsTemporary, bool IsMutable);
+  Descriptor(const DeclTy &D, const Type *SourceTy, const Descriptor *Elem,
+             MetadataSize MD, unsigned NumElems, bool IsConst, bool IsTemporary,
+             bool IsMutable);
 
   /// Allocates a descriptor for an array of composites of unknown size.
   Descriptor(const DeclTy &D, const Descriptor *Elem, MetadataSize MD,

clang/lib/AST/ByteCode/DynamicAllocator.cpp

@@ -57,8 +57,10 @@ Block *DynamicAllocator::allocate(const Descriptor *ElementDesc,
   assert(ElementDesc->getMetadataSize() == 0);
   // Create a new descriptor for an array of the specified size and
   // element type.
+  // FIXME: Pass proper element type.
   const Descriptor *D = allocateDescriptor(
-      ElementDesc->asExpr(), ElementDesc, Descriptor::InlineDescMD, NumElements,
+      ElementDesc->asExpr(), nullptr, ElementDesc, Descriptor::InlineDescMD,
+      NumElements,
       /*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false);
   return allocate(D, EvalID, AllocForm);
 }

clang/lib/AST/ByteCode/Program.cpp

@@ -419,7 +419,7 @@ Descriptor *Program::createDescriptor(const DeclTy &D, const Type *Ty,
         unsigned ElemSize = ElemDesc->getAllocSize() + sizeof(InlineDescriptor);
         if (std::numeric_limits<unsigned>::max() / ElemSize <= NumElems)
           return {};
-        return allocateDescriptor(D, ElemDesc, MDSize, NumElems, IsConst,
+        return allocateDescriptor(D, Ty, ElemDesc, MDSize, NumElems, IsConst,
                                   IsTemporary, IsMutable);
       }
     }

clang/unittests/AST/ByteCode/toAPValue.cpp

@@ -254,3 +254,69 @@ TEST(ToAPValue, MemberPointers) {
     ASSERT_EQ(A.getKind(), APValue::MemberPointer);
   }
 }
+
+/// Compare outputs between the two interpreters.
+TEST(ToAPValue, Comparison) {
+  constexpr char Code[] =
+      "constexpr int GI = 12;\n"
+      "constexpr const int *PI = &GI;\n"
+      "struct S{int a; };\n"
+      "constexpr S GS[] = {{}, {}};\n"
+      "constexpr const S* OS = GS + 1;\n"
+      "constexpr S DS = *OS;\n"
+      "constexpr int IA[2][2][2] = {{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}};\n"
+      "constexpr const int *PIA = IA[1][1];\n";
+
+  for (const char *Arg : {"", "-fexperimental-new-constant-interpreter"}) {
+    auto AST = tooling::buildASTFromCodeWithArgs(Code, {Arg});
+
+    auto getDecl = [&](const char *Name) -> const VarDecl * {
+      auto Nodes =
+          match(valueDecl(hasName(Name)).bind("var"), AST->getASTContext());
+      assert(Nodes.size() == 1);
+      const auto *D = Nodes[0].getNodeAs<ValueDecl>("var");
+      assert(D);
+      return cast<VarDecl>(D);
+    };
+
+    {
+      const VarDecl *GIDecl = getDecl("GI");
+      const APValue *V = GIDecl->evaluateValue();
+      ASSERT_TRUE(V->isInt());
+    }
+
+    {
+      const VarDecl *GIDecl = getDecl("GI");
+      const VarDecl *PIDecl = getDecl("PI");
+      const APValue *V = PIDecl->evaluateValue();
+      ASSERT_TRUE(V->isLValue());
+      ASSERT_TRUE(V->hasLValuePath());
+      ASSERT_EQ(V->getLValueBase().get<const ValueDecl *>(), GIDecl);
+      ASSERT_EQ(V->getLValuePath().size(), 0u);
+    }
+
+    {
+      const APValue *V = getDecl("OS")->evaluateValue();
+      ASSERT_TRUE(V->isLValue());
+      ASSERT_EQ(V->getLValueOffset().getQuantity(), (unsigned)sizeof(int));
+      ASSERT_TRUE(V->hasLValuePath());
+      ASSERT_EQ(V->getLValuePath().size(), 1u);
+      ASSERT_EQ(V->getLValuePath()[0].getAsArrayIndex(), 1u);
+    }
+
+    {
+      const APValue *V = getDecl("DS")->evaluateValue();
+      ASSERT_TRUE(V->isStruct());
+    }
+    {
+      const APValue *V = getDecl("PIA")->evaluateValue();
+      ASSERT_TRUE(V->isLValue());
+      ASSERT_TRUE(V->hasLValuePath());
+      ASSERT_EQ(V->getLValuePath().size(), 3u);
+      ASSERT_EQ(V->getLValuePath()[0].getAsArrayIndex(), 1u);
+      ASSERT_EQ(V->getLValuePath()[1].getAsArrayIndex(), 1u);
+      ASSERT_EQ(V->getLValuePath()[2].getAsArrayIndex(), 0u);
+      ASSERT_EQ(V->getLValueOffset().getQuantity(), (unsigned)sizeof(int) * 6);
+    }
+  }
+}