nicer error messages when required 'generates' clause is missing

Currently, it is possible to make the Torque compiler emit uncompilable
C++ code if a 'generates' clause is missing. Rather than making the
developer spelunk through generated code to find out what went wrong,
we can catch this error earlier and print a useful message.

Bug: v8:7793
Change-Id: I49fabc1d39f398bf322523901941494b8dab0506
Reviewed-on: https://chromium-review.googlesource.com/c/1477964Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#59744}

src/torque/types.cc

@@ -75,7 +75,25 @@ bool Type::IsAbstractName(const std::string& name) const {
   return AbstractType::cast(this)->name() == name;
 }
 
-std::string AbstractType::GetGeneratedTNodeTypeName() const {
+std::string Type::GetGeneratedTypeName() const {
+  std::string result = GetGeneratedTypeNameImpl();
+  if (result.empty() || result == "compiler::TNode<>") {
+    ReportError("Generated type is required for type '", ToString(),
+                "'. Use 'generates' clause in definition.");
+  }
+  return result;
+}
+
+std::string Type::GetGeneratedTNodeTypeName() const {
+  std::string result = GetGeneratedTNodeTypeNameImpl();
+  if (result.empty()) {
+    ReportError("Generated TNode type is required for type '", ToString(),
+                "'. Use 'generates' clause in definition.");
+  }
+  return result;
+}
+
+std::string AbstractType::GetGeneratedTNodeTypeNameImpl() const {
   return generated_type_;
 }
 
@@ -124,7 +142,7 @@ std::string UnionType::MangledName() const {
   return result.str();
 }
 
-std::string UnionType::GetGeneratedTNodeTypeName() const {
+std::string UnionType::GetGeneratedTNodeTypeNameImpl() const {
   if (types_.size() <= 3) {
     std::set<std::string> members;
     for (const Type* t : types_) {
@@ -250,7 +268,7 @@ const Field& AggregateType::LookupField(const std::string& name) const {
   ReportError("no field ", name, " found");
 }
 
-std::string StructType::GetGeneratedTypeName() const {
+std::string StructType::GetGeneratedTypeNameImpl() const {
   return nspace()->ExternalName() + "::" + name();
 }
 
@@ -300,7 +318,7 @@ bool ClassType::HasIndexedField() const {
   return false;
 }
 
-std::string ClassType::GetGeneratedTNodeTypeName() const {
+std::string ClassType::GetGeneratedTNodeTypeNameImpl() const {
   if (!IsExtern()) return generates_;
   std::string prefix = nspace()->IsDefaultNamespace()
                            ? std::string{}
@@ -308,7 +326,7 @@ std::string ClassType::GetGeneratedTNodeTypeName() const {
   return prefix + generates_;
 }
 
-std::string ClassType::GetGeneratedTypeName() const {
+std::string ClassType::GetGeneratedTypeNameImpl() const {
   return IsConstexpr() ? GetGeneratedTNodeTypeName()
                        : "compiler::TNode<" + GetGeneratedTNodeTypeName() + ">";
 }

src/torque/types.h

@@ -120,8 +120,8 @@ class Type : public TypeBase {
     return IsAbstractName(CONSTEXPR_BOOL_TYPE_STRING);
   }
   bool IsVoidOrNever() const { return IsVoid() || IsNever(); }
-  virtual std::string GetGeneratedTypeName() const = 0;
-  virtual std::string GetGeneratedTNodeTypeName() const = 0;
+  std::string GetGeneratedTypeName() const;
+  std::string GetGeneratedTNodeTypeName() const;
   virtual bool IsConstexpr() const = 0;
   virtual bool IsTransient() const { return false; }
   virtual const Type* NonConstexprVersion() const = 0;
@@ -135,6 +135,8 @@ class Type : public TypeBase {
   void set_parent(const Type* t) { parent_ = t; }
   int Depth() const;
   virtual std::string ToExplicitString() const = 0;
+  virtual std::string GetGeneratedTypeNameImpl() const = 0;
+  virtual std::string GetGeneratedTNodeTypeNameImpl() const = 0;
 
  private:
   bool IsAbstractName(const std::string& name) const;
@@ -180,14 +182,14 @@ std::ostream& operator<<(std::ostream& os, const Field& name_and_type);
 class TopType final : public Type {
  public:
   DECLARE_TYPE_BOILERPLATE(TopType)
-  virtual std::string MangledName() const { return "top"; }
-  virtual std::string GetGeneratedTypeName() const { UNREACHABLE(); }
-  virtual std::string GetGeneratedTNodeTypeName() const {
+  std::string MangledName() const override { return "top"; }
+  std::string GetGeneratedTypeNameImpl() const override { UNREACHABLE(); }
+  std::string GetGeneratedTNodeTypeNameImpl() const override {
     return source_type_->GetGeneratedTNodeTypeName();
   }
-  virtual bool IsConstexpr() const { return false; }
-  virtual const Type* NonConstexprVersion() const { return nullptr; }
-  virtual std::string ToExplicitString() const {
+  bool IsConstexpr() const override { return false; }
+  const Type* NonConstexprVersion() const override { return nullptr; }
+  std::string ToExplicitString() const override {
     std::stringstream s;
     s << "inaccessible " + source_type_->ToString();
     return s.str();
@@ -216,11 +218,11 @@ class AbstractType final : public Type {
     std::replace(str.begin(), str.end(), ' ', '_');
     return "AT" + str;
   }
-  std::string GetGeneratedTypeName() const override {
+  std::string GetGeneratedTypeNameImpl() const override {
     return IsConstexpr() ? generated_type_
                          : "compiler::TNode<" + generated_type_ + ">";
   }
-  std::string GetGeneratedTNodeTypeName() const override;
+  std::string GetGeneratedTNodeTypeNameImpl() const override;
   bool IsConstexpr() const override {
     return name().substr(0, strlen(CONSTEXPR_TYPE_PREFIX)) ==
            CONSTEXPR_TYPE_PREFIX;
@@ -258,10 +260,10 @@ class BuiltinPointerType final : public Type {
   DECLARE_TYPE_BOILERPLATE(BuiltinPointerType)
   std::string ToExplicitString() const override;
   std::string MangledName() const override;
-  std::string GetGeneratedTypeName() const override {
+  std::string GetGeneratedTypeNameImpl() const override {
     return parent()->GetGeneratedTypeName();
   }
-  std::string GetGeneratedTNodeTypeName() const override {
+  std::string GetGeneratedTNodeTypeNameImpl() const override {
     return parent()->GetGeneratedTNodeTypeName();
   }
   bool IsConstexpr() const override {
@@ -312,10 +314,10 @@ class UnionType final : public Type {
   DECLARE_TYPE_BOILERPLATE(UnionType)
   std::string ToExplicitString() const override;
   std::string MangledName() const override;
-  std::string GetGeneratedTypeName() const override {
+  std::string GetGeneratedTypeNameImpl() const override {
     return "compiler::TNode<" + GetGeneratedTNodeTypeName() + ">";
   }
-  std::string GetGeneratedTNodeTypeName() const override;
+  std::string GetGeneratedTNodeTypeNameImpl() const override;
 
   bool IsConstexpr() const override {
     DCHECK_EQ(false, parent()->IsConstexpr());
@@ -401,8 +403,8 @@ class AggregateType : public Type {
  public:
   DECLARE_TYPE_BOILERPLATE(AggregateType)
   std::string MangledName() const override { return name_; }
-  std::string GetGeneratedTypeName() const override { UNREACHABLE(); }
-  std::string GetGeneratedTNodeTypeName() const override { UNREACHABLE(); }
+  std::string GetGeneratedTypeNameImpl() const override { UNREACHABLE(); }
+  std::string GetGeneratedTNodeTypeNameImpl() const override { UNREACHABLE(); }
   const Type* NonConstexprVersion() const override { return this; }
 
   bool IsConstexpr() const override { return false; }
@@ -449,7 +451,7 @@ class StructType final : public AggregateType {
  public:
   DECLARE_TYPE_BOILERPLATE(StructType)
   std::string ToExplicitString() const override;
-  std::string GetGeneratedTypeName() const override;
+  std::string GetGeneratedTypeNameImpl() const override;
 
   void SetDerivedFrom(const ClassType* derived_from) {
     derived_from_ = derived_from;
@@ -474,8 +476,8 @@ class ClassType final : public AggregateType {
  public:
   DECLARE_TYPE_BOILERPLATE(ClassType)
   std::string ToExplicitString() const override;
-  std::string GetGeneratedTypeName() const override;
-  std::string GetGeneratedTNodeTypeName() const override;
+  std::string GetGeneratedTypeNameImpl() const override;
+  std::string GetGeneratedTNodeTypeNameImpl() const override;
   bool IsExtern() const { return is_extern_; }
   bool IsTransient() const override { return transient_; }
   bool HasIndexedField() const override;