Bug 1790626 - wasm: Manually serialize/deserialize PackedType to prepare for it not being POD. r=yury

PackedType will store a pointer to *TypeDef in a later commit, making it
non-cacheable POD. We therefore need to specially handle it in serialization.
This commit starts preparing for that.

Differential Revision: https://phabricator.services.mozilla.com/D157386

js/src/wasm/WasmModuleTypes.h

@@ -614,9 +614,6 @@ struct TableDesc {
   uint32_t initialLength;
   Maybe<uint32_t> maximumLength;
 
-  WASM_CHECK_CACHEABLE_POD(elemType, isImportedOrExported, isAsmJS,
-                           globalDataOffset, initialLength, maximumLength);
-
   TableDesc() = default;
   TableDesc(RefType elemType, uint32_t initialLength,
             Maybe<uint32_t> maximumLength, bool isAsmJS,
@@ -629,8 +626,6 @@ struct TableDesc {
         maximumLength(maximumLength) {}
 };
 
-WASM_DECLARE_CACHEABLE_POD(TableDesc);
-
 using TableDescVector = Vector<TableDesc, 0, SystemAllocPolicy>;
 
 }  // namespace wasm

js/src/wasm/WasmSerialize.cpp

@@ -412,16 +412,56 @@ CoderResult CodeShareableBytes(Coder<mode>& coder,
   return CodePodVector(coder, &item->bytes);
 }
 
+// WasmValType.h
+
+template <CoderMode mode>
+CoderResult CodeValType(Coder<mode>& coder, CoderArg<mode, ValType> item) {
+  if constexpr (mode == MODE_DECODE) {
+    return coder.readBytes((void*)item, sizeof(ValType));
+  } else {
+    return coder.writeBytes((const void*)item, sizeof(ValType));
+  }
+}
+
+CoderResult CodeFieldType(Coder<MODE_DECODE>& coder, FieldType* item) {
+  return coder.readBytes((void*)item, sizeof(FieldType));
+}
+
+template <CoderMode mode>
+CoderResult CodeFieldType(Coder<mode>& coder, const FieldType* item) {
+  STATIC_ASSERT_ENCODING_OR_SIZING;
+  return coder.writeBytes((const void*)item, sizeof(FieldType));
+}
+
+CoderResult CodeRefType(Coder<MODE_DECODE>& coder, RefType* item) {
+  return coder.readBytes((void*)item, sizeof(RefType));
+}
+
+template <CoderMode mode>
+CoderResult CodeRefType(Coder<mode>& coder, const RefType* item) {
+  STATIC_ASSERT_ENCODING_OR_SIZING;
+  return coder.writeBytes((const void*)item, sizeof(RefType));
+}
+
+// WasmValue.h
+
+template <CoderMode mode>
+CoderResult CodeLitVal(Coder<mode>& coder, CoderArg<mode, LitVal> item) {
+  MOZ_TRY(CodeValType(coder, &item->type_));
+  MOZ_TRY(CodePod(coder, &item->cell_));
+  return Ok();
+}
+
 // WasmInitExpr.h
 
 template <CoderMode mode>
 CoderResult CodeInitExpr(Coder<mode>& coder, CoderArg<mode, InitExpr> item) {
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::InitExpr, 80);
   MOZ_TRY(CodePod(coder, &item->kind_));
-  MOZ_TRY(CodePod(coder, &item->type_));
+  MOZ_TRY(CodeValType(coder, &item->type_));
   switch (item->kind_) {
     case InitExprKind::Literal:
-      MOZ_TRY(CodePod(coder, &item->literal_));
+      MOZ_TRY(CodeLitVal(coder, &item->literal_));
       break;
     case InitExprKind::Variable:
       MOZ_TRY(CodePodVector(coder, &item->bytecode_));
@@ -437,21 +477,40 @@ CoderResult CodeInitExpr(Coder<mode>& coder, CoderArg<mode, InitExpr> item) {
 template <CoderMode mode>
 CoderResult CodeFuncType(Coder<mode>& coder, CoderArg<mode, FuncType> item) {
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::FuncType, 208);
-  MOZ_TRY(CodePodVector(coder, &item->results_));
-  MOZ_TRY(CodePodVector(coder, &item->args_));
+  MOZ_TRY((CodeVector<mode, ValType, &CodeValType<mode>>(coder, &item->args_)));
+  MOZ_TRY(
+      (CodeVector<mode, ValType, &CodeValType<mode>>(coder, &item->results_)));
   MOZ_TRY(CodePod(coder, &item->immediateTypeId_));
   return Ok();
 }
 
+template <CoderMode mode>
+CoderResult CodeStructField(Coder<mode>& coder,
+                            CoderArg<mode, StructField> item) {
+  MOZ_TRY(CodeFieldType(coder, &item->type));
+  MOZ_TRY(CodePod(coder, &item->offset));
+  MOZ_TRY(CodePod(coder, &item->isMutable));
+  return Ok();
+}
+
 template <CoderMode mode>
 CoderResult CodeStructType(Coder<mode>& coder,
                            CoderArg<mode, StructType> item) {
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::StructType, 48);
-  MOZ_TRY(CodePodVector(coder, &item->fields_));
+  MOZ_TRY((CodeVector<mode, StructField, &CodeStructField<mode>>(
+      coder, &item->fields_)));
   MOZ_TRY(CodePod(coder, &item->size_));
   return Ok();
 }
 
+template <CoderMode mode>
+CoderResult CodeArrayType(Coder<mode>& coder, CoderArg<mode, ArrayType> item) {
+  WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::ArrayType, 48);
+  MOZ_TRY(CodeFieldType(coder, &item->elementType_));
+  MOZ_TRY(CodePod(coder, &item->isMutable_));
+  return Ok();
+}
+
 template <CoderMode mode>
 CoderResult CodeTypeDef(Coder<mode>& coder, CoderArg<mode, TypeDef> item) {
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::TypeDef, 216);
@@ -477,7 +536,10 @@ CoderResult CodeTypeDef(Coder<mode>& coder, CoderArg<mode, TypeDef> item) {
       break;
     }
     case TypeDefKind::Array: {
-      MOZ_TRY(CodePod(coder, &item->arrayType_));
+      if constexpr (mode == MODE_DECODE) {
+        new (&item->arrayType_) ArrayType();
+      }
+      MOZ_TRY(CodeArrayType(coder, &item->arrayType_));
       break;
     }
     case TypeDefKind::None: {
@@ -525,7 +587,8 @@ CoderResult CodeGlobalDesc(Coder<mode>& coder,
 template <CoderMode mode>
 CoderResult CodeTagType(Coder<mode>& coder, CoderArg<mode, TagType> item) {
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::TagType, 168);
-  MOZ_TRY(CodePodVector(coder, &item->argTypes_));
+  MOZ_TRY(
+      (CodeVector<mode, ValType, &CodeValType<mode>>(coder, &item->argTypes_)));
   MOZ_TRY(CodePodVector(coder, &item->argOffsets_));
   MOZ_TRY(CodePod(coder, &item->size_));
   return Ok();
@@ -548,7 +611,7 @@ CoderResult CodeElemSegment(Coder<mode>& coder,
   WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::ElemSegment, 184);
   MOZ_TRY(CodePod(coder, &item->kind));
   MOZ_TRY(CodePod(coder, &item->tableIndex));
-  MOZ_TRY(CodePod(coder, &item->elemType));
+  MOZ_TRY(CodeRefType(coder, &item->elemType));
   MOZ_TRY((CodeMaybe<mode, InitExpr, &CodeInitExpr<mode>>(
       coder, &item->offsetIfActive)));
   MOZ_TRY(CodePodVector(coder, &item->elemFuncIndices));
@@ -575,6 +638,18 @@ CoderResult CodeCustomSection(Coder<mode>& coder,
   return Ok();
 }
 
+template <CoderMode mode>
+CoderResult CodeTableDesc(Coder<mode>& coder, CoderArg<mode, TableDesc> item) {
+  WASM_VERIFY_SERIALIZATION_FOR_SIZE(wasm::TableDesc, 48);
+  MOZ_TRY(CodeRefType(coder, &item->elemType));
+  MOZ_TRY(CodePod(coder, &item->isImportedOrExported));
+  MOZ_TRY(CodePod(coder, &item->isAsmJS));
+  MOZ_TRY(CodePod(coder, &item->globalDataOffset));
+  MOZ_TRY(CodePod(coder, &item->initialLength));
+  MOZ_TRY(CodePod(coder, &item->maximumLength));
+  return Ok();
+}
+
 // WasmCodegenTypes.h
 
 template <CoderMode mode>
@@ -805,7 +880,8 @@ CoderResult CodeMetadata(Coder<mode>& coder,
   MOZ_TRY((CodePod(coder, &item->typeIdsOffsetStart)));
   MOZ_TRY((CodeVector<mode, GlobalDesc, &CodeGlobalDesc<mode>>(
       coder, &item->globals)));
-  MOZ_TRY(CodePodVector(coder, &item->tables));
+  MOZ_TRY((
+      CodeVector<mode, TableDesc, &CodeTableDesc<mode>>(coder, &item->tables)));
   MOZ_TRY((CodeVector<mode, TagDesc, &CodeTagDesc<mode>>(coder, &item->tags)));
   MOZ_TRY(CodePod(coder, &item->moduleName));
   MOZ_TRY(CodePodVector(coder, &item->funcNames));

js/src/wasm/WasmTypeDef.h

@@ -217,12 +217,8 @@ struct StructField {
   FieldType type;
   uint32_t offset;
   bool isMutable;
-
-  WASM_CHECK_CACHEABLE_POD(type, offset, isMutable);
 };
 
-WASM_DECLARE_CACHEABLE_POD(StructField);
-
 using StructFieldVector = Vector<StructField, 0, SystemAllocPolicy>;
 
 class StructType {
@@ -300,9 +296,8 @@ class ArrayType {
   FieldType elementType_;  // field type
   bool isMutable_;         // mutability
 
-  WASM_CHECK_CACHEABLE_POD(elementType_, isMutable_);
-
  public:
+  ArrayType() : isMutable_(false) {}
   ArrayType(FieldType elementType, bool isMutable)
       : elementType_(elementType), isMutable_(isMutable) {}
 

js/src/wasm/WasmValType.h

@@ -57,8 +57,6 @@ union PackedTypeCode {
     PackedRepr pointerTag_ : PointerTagBits;
   };
 
-  WASM_CHECK_CACHEABLE_POD(bits_);
-
  public:
   static constexpr uint32_t NoTypeCode = (1 << TypeCodeBits) - 1;
   static constexpr uint32_t NoTypeIndex = (1 << TypeIndexBits) - 1;
@@ -162,11 +160,7 @@ union PackedTypeCode {
   }
 };
 
-WASM_DECLARE_CACHEABLE_POD(PackedTypeCode);
-
 static_assert(sizeof(PackedTypeCode) == sizeof(uint32_t), "packed");
-static_assert(std::is_pod_v<PackedTypeCode>,
-              "must be POD to be simply serialized/deserialized");
 
 // An enum that describes the representation classes for tables; The table
 // element type is mapped into this by Table::repr().
@@ -188,8 +182,6 @@ class RefType {
  private:
   PackedTypeCode ptc_;
 
-  WASM_CHECK_CACHEABLE_POD(ptc_);
-
 #ifdef DEBUG
   bool isValid() const {
     switch (ptc_.typeCode()) {
@@ -265,8 +257,6 @@ class RefType {
   bool operator!=(const RefType& that) const { return ptc_ != that.ptc_; }
 };
 
-WASM_DECLARE_CACHEABLE_POD(RefType);
-
 class FieldTypeTraits {
  public:
   enum Kind {
@@ -415,8 +405,6 @@ class PackedType : public T {
  protected:
   PackedTypeCode tc_;
 
-  WASM_CHECK_CACHEABLE_POD(tc_);
-
   explicit PackedType(TypeCode c) : tc_(PackedTypeCode::pack(c)) {
     MOZ_ASSERT(c != AbstractReferenceTypeIndexCode);
     MOZ_ASSERT(isValid());
@@ -692,9 +680,6 @@ class PackedType : public T {
 using ValType = PackedType<ValTypeTraits>;
 using FieldType = PackedType<FieldTypeTraits>;
 
-WASM_DECLARE_CACHEABLE_POD(ValType);
-WASM_DECLARE_CACHEABLE_POD(FieldType);
-
 // The dominant use of this data type is for locals and args, and profiling
 // with ZenGarden and Tanks suggests an initial size of 16 minimises heap
 // allocation, both in terms of blocks and bytes.

js/src/wasm/WasmValue.h

@@ -276,21 +276,18 @@ class LitVal {
 
     Cell() : v128_() {}
     ~Cell() = default;
+
+    WASM_CHECK_CACHEABLE_POD(i32_, i64_, f32_, f64_, v128_);
+    WASM_ALLOW_NON_CACHEABLE_POD_FIELD(
+        ref_,
+        "The pointer value in ref_ is guaranteed to always be null in a "
+        "LitVal.");
   };
 
  protected:
   ValType type_;
   Cell cell_;
 
-  // We check the fields of cell_ here instead of in the union to avoid a
-  // template issue. In addition, Cell is only cacheable POD when used in
-  // LitVal and not Val, so checking here makes sense.
-  WASM_CHECK_CACHEABLE_POD(type_, cell_.i32_, cell_.i64_, cell_.f32_,
-                           cell_.f64_, cell_.v128_);
-  WASM_ALLOW_NON_CACHEABLE_POD_FIELD(
-      cell_.ref_,
-      "The pointer value in ref_ is guaranteed to always be null in a LitVal.");
-
  public:
   LitVal() : type_(ValType()), cell_{} {}
 
@@ -369,9 +366,11 @@ class LitVal {
     MOZ_ASSERT(type_ == ValType::V128);
     return cell_.v128_;
   }
+
+  WASM_DECLARE_FRIEND_SERIALIZE(LitVal);
 };
 
-WASM_DECLARE_CACHEABLE_POD(LitVal);
+WASM_DECLARE_CACHEABLE_POD(LitVal::Cell);
 
 // A Val is a LitVal that can contain (non-null) pointers to GC things. All Vals
 // must be used with the rooting APIs as they may contain JS objects.