Added upb compiler written in C++ as a normal protoc plugin.

1 files changed, 104 insertions, 0 deletions

diff --git a/upbc/message_layout.h b/upbc/message_layout.h
new file mode 100644
index 0000000..bdcc336
--- /dev/null
+++ b/upbc/message_layout.h
@@ -0,0 +1,104 @@
+
+#ifndef UPBC_MESSAGE_LAYOUT_H
+#define UPBC_MESSAGE_LAYOUT_H
+
+#include <unordered_map>
+#include "absl/base/macros.h"
+#include "google/protobuf/descriptor.h"
+
+namespace upbc {
+
+class MessageLayout {
+ public:
+  struct Size {
+    void Add(const Size& other) {
+      size32 += other.size32;
+      size64 += other.size64;
+    }
+
+    void MaxFrom(const Size& other) {
+      size32 = std::max(size32, other.size32);
+      size64 = std::max(size64, other.size64);
+    }
+
+    void AlignUp(const Size& align) {
+      size32 = Align(size32, align.size32);
+      size64 = Align(size64, align.size64);
+    }
+
+    int64_t size32;
+    int64_t size64;
+  };
+
+  struct SizeAndAlign {
+    Size size;
+    Size align;
+
+    void MaxFrom(const SizeAndAlign& other) {
+      size.MaxFrom(other.size);
+      align.MaxFrom(other.align);
+    }
+  };
+
+  MessageLayout(const google::protobuf::Descriptor* descriptor) {
+    ComputeLayout(descriptor);
+  }
+
+  Size GetFieldOffset(const google::protobuf::FieldDescriptor* field) const {
+    return GetMapValue(field_offsets_, field);
+  }
+
+  Size GetOneofCaseOffset(
+      const google::protobuf::OneofDescriptor* oneof) const {
+    return GetMapValue(oneof_case_offsets_, oneof);
+  }
+
+  int GetHasbitIndex(const google::protobuf::FieldDescriptor* field) const {
+    return GetMapValue(hasbit_indexes_, field);
+  }
+
+  Size message_size() const { return size_; }
+
+  static bool HasHasbit(const google::protobuf::FieldDescriptor* field);
+
+ private:
+  void ComputeLayout(const google::protobuf::Descriptor* descriptor);
+  void PlaceNonOneofFields(const google::protobuf::Descriptor* descriptor);
+  void PlaceOneofFields(const google::protobuf::Descriptor* descriptor);
+  Size Place(SizeAndAlign size_and_align);
+
+  template <class K, class V>
+  static V GetMapValue(const std::unordered_map<K, V>& map, K key) {
+    auto iter = map.find(key);
+    if (iter == map.end()) {
+      fprintf(stderr, "No value for field.\n");
+      abort();
+    }
+    return iter->second;
+  }
+
+  static bool IsPowerOfTwo(size_t val) {
+    return (val & (val - 1)) == 0;
+  }
+
+  static size_t Align(size_t val, size_t align) {
+    ABSL_ASSERT(IsPowerOfTwo(align));
+    return (val + align - 1) & ~(align - 1);
+  }
+
+  static SizeAndAlign SizeOf(const google::protobuf::FieldDescriptor* field);
+  static int64_t FieldLayoutRank(const google::protobuf::FieldDescriptor* field);
+
+  std::unordered_map<const google::protobuf::FieldDescriptor*, Size>
+      field_offsets_;
+  std::unordered_map<const google::protobuf::FieldDescriptor*, int>
+      hasbit_indexes_;
+  std::unordered_map<const google::protobuf::OneofDescriptor*, Size>
+      oneof_case_offsets_;
+  Size maxalign_;
+  Size size_;
+};
+
+}  // namespace upbc
+
+#endif  // UPBC_MESSAGE_LAYOUT_H