1 files changed, 92 insertions, 4 deletions

diff --git a/runtime/quicken_info.h b/runtime/quicken_info.h
index ce11f3c19b..52eca61c06 100644
--- a/runtime/quicken_info.h
+++ b/runtime/quicken_info.h
@@ -17,15 +17,93 @@
 #ifndef ART_RUNTIME_QUICKEN_INFO_H_
 #define ART_RUNTIME_QUICKEN_INFO_H_
 
+#include "base/array_ref.h"
 #include "dex/dex_instruction.h"
+#include "leb128.h"
 
 namespace art {
 
-// QuickenInfoTable is a table of 16 bit dex indices. There is one slot fo every instruction that is
-// possibly dequickenable.
+// Table for getting the offset of quicken info. Doesn't have one slot for each index, so a
+// combination of iteration and indexing is required to get the quicken info for a given dex method
+// index.
+class QuickenInfoOffsetTableAccessor {
+ public:
+  using TableType = uint32_t;
+  static constexpr uint32_t kElementsPerIndex = 16;
+
+  class Builder {
+   public:
+    explicit Builder(std::vector<uint8_t>* out_data) : out_data_(out_data) {}
+
+    void AddOffset(uint32_t index) {
+      out_data_->insert(out_data_->end(),
+                        reinterpret_cast<const uint8_t*>(&index),
+                        reinterpret_cast<const uint8_t*>(&index + 1));
+    }
+
+   private:
+    std::vector<uint8_t>* const out_data_;
+  };
+
+  // The table only covers every kElementsPerIndex indices.
+  static bool IsCoveredIndex(uint32_t index) {
+    return index % kElementsPerIndex == 0;
+  }
+
+  explicit QuickenInfoOffsetTableAccessor(const uint8_t* data, uint32_t max_index)
+      : table_(reinterpret_cast<const uint32_t*>(data)),
+        num_indices_(RoundUp(max_index, kElementsPerIndex) / kElementsPerIndex) {}
+
+  size_t SizeInBytes() const {
+    return NumIndices() * sizeof(table_[0]);
+  }
+
+  uint32_t NumIndices() const {
+    return num_indices_;
+  }
+
+  // Returns the offset for the index at or before the desired index. If the offset is for an index
+  // before the desired one, remainder is how many elements to traverse to reach the desired index.
+  TableType ElementOffset(uint32_t index, uint32_t* remainder) const {
+    *remainder = index % kElementsPerIndex;
+    return table_[index / kElementsPerIndex];
+  }
+
+  const uint8_t* DataEnd() const {
+    return reinterpret_cast<const uint8_t*>(table_ + NumIndices());
+  }
+
+  static uint32_t Alignment() {
+    return alignof(TableType);
+  }
+
+ private:
+  const TableType* table_;
+  uint32_t num_indices_;
+};
+
+// QuickenInfoTable is a table of 16 bit dex indices. There is one slot for every instruction that
+// is possibly dequickenable.
 class QuickenInfoTable {
  public:
-  explicit QuickenInfoTable(const uint8_t* data) : data_(data) {}
+  class Builder {
+   public:
+    Builder(std::vector<uint8_t>* out_data, size_t num_elements) : out_data_(out_data) {
+      EncodeUnsignedLeb128(out_data_, num_elements);
+    }
+
+    void AddIndex(uint16_t index) {
+      out_data_->push_back(static_cast<uint8_t>(index));
+      out_data_->push_back(static_cast<uint8_t>(index >> 8));
+    }
+
+   private:
+    std::vector<uint8_t>* const out_data_;
+  };
+
+  explicit QuickenInfoTable(ArrayRef<const uint8_t> data)
+      : data_(data.data()),
+        num_elements_(!data.empty() ? DecodeUnsignedLeb128(&data_) : 0u) {}
 
   bool IsNull() const {
     return data_ == nullptr;
@@ -44,8 +122,18 @@ class QuickenInfoTable {
     return bytes / sizeof(uint16_t);
   }
 
+  static size_t SizeInBytes(ArrayRef<const uint8_t> data) {
+    QuickenInfoTable table(data);
+    return table.data_ + table.NumIndices() * 2 - data.data();
+  }
+
+  uint32_t NumIndices() const {
+    return num_elements_;
+  }
+
  private:
-  const uint8_t* const data_;
+  const uint8_t* data_;
+  const uint32_t num_elements_;
 
   DISALLOW_COPY_AND_ASSIGN(QuickenInfoTable);
 };