Cache field lowering info in mir_graph.

Change-Id: I9f9d76e3ae6c31e88bdf3f59820d31a625da020f
diff --git a/compiler/dex/mir_field_info.h b/compiler/dex/mir_field_info.h
new file mode 100644
index 0000000..41cb4ce
--- /dev/null
+++ b/compiler/dex/mir_field_info.h
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_COMPILER_DEX_MIR_FIELD_INFO_H_
+#define ART_COMPILER_DEX_MIR_FIELD_INFO_H_
+
+#include "base/macros.h"
+#include "dex_file.h"
+#include "offsets.h"
+
+namespace art {
+
+class CompilerDriver;
+class DexCompilationUnit;
+
+/*
+ * Field info is calculated from the perspective of the compilation unit that accesses
+ * the field and stored in that unit's MIRGraph. Therefore it does not need to reference the
+ * dex file or method for which it has been calculated. However, we do store the declaring
+ * field index, class index and dex file of the resolved field to help distinguish between fields.
+ */
+
+class MirFieldInfo {
+ public:
+  uint16_t FieldIndex() const {
+    return field_idx_;
+  }
+
+  bool IsStatic() const {
+    return (flags_ & kFlagIsStatic) != 0u;
+  }
+
+  bool IsResolved() const {
+    return declaring_dex_file_ != nullptr;
+  }
+
+  const DexFile* DeclaringDexFile() const {
+    return declaring_dex_file_;
+  }
+
+  uint16_t DeclaringClassIndex() const {
+    return declaring_class_idx_;
+  }
+
+  uint16_t DeclaringFieldIndex() const {
+    return declaring_field_idx_;
+  }
+
+  bool IsVolatile() const {
+    return (flags_ & kFlagIsVolatile) != 0u;
+  }
+
+ protected:
+  enum {
+    kBitIsStatic = 0,
+    kBitIsVolatile,
+    kFieldInfoBitEnd
+  };
+  static constexpr uint16_t kFlagIsVolatile = 1u << kBitIsVolatile;
+  static constexpr uint16_t kFlagIsStatic = 1u << kBitIsStatic;
+
+  MirFieldInfo(uint16_t field_idx, uint16_t flags)
+      : field_idx_(field_idx),
+        flags_(flags),
+        declaring_field_idx_(0u),
+        declaring_class_idx_(0u),
+        declaring_dex_file_(nullptr) {
+  }
+
+  // Make copy-ctor/assign/dtor protected to avoid slicing.
+  MirFieldInfo(const MirFieldInfo& other) = default;
+  MirFieldInfo& operator=(const MirFieldInfo& other) = default;
+  ~MirFieldInfo() = default;
+
+  // The field index in the compiling method's dex file.
+  uint16_t field_idx_;
+  // Flags, for volatility and derived class data.
+  uint16_t flags_;
+  // The field index in the dex file that defines field, 0 if unresolved.
+  uint16_t declaring_field_idx_;
+  // The type index of the class declaring the field, 0 if unresolved.
+  uint16_t declaring_class_idx_;
+  // The dex file that defines the class containing the field and the field, nullptr if unresolved.
+  const DexFile* declaring_dex_file_;
+};
+
+class MirIFieldLoweringInfo : public MirFieldInfo {
+ public:
+  // For each requested instance field retrieve the field's declaring location (dex file, class
+  // index and field index) and volatility and compute the whether we can fast path the access
+  // with IGET/IPUT. For fast path fields, retrieve the field offset.
+  static void Resolve(CompilerDriver* compiler_driver, const DexCompilationUnit* mUnit,
+                      MirIFieldLoweringInfo* field_infos, size_t count)
+      LOCKS_EXCLUDED(Locks::mutator_lock_);
+
+  // Construct an unresolved instance field lowering info.
+  explicit MirIFieldLoweringInfo(uint16_t field_idx)
+      : MirFieldInfo(field_idx, kFlagIsVolatile),  // Without kFlagIsStatic.
+        field_offset_(0u) {
+  }
+
+  bool FastGet() const {
+    return (flags_ & kFlagFastGet) != 0u;
+  }
+
+  bool FastPut() const {
+    return (flags_ & kFlagFastPut) != 0u;
+  }
+
+  MemberOffset FieldOffset() const {
+    return field_offset_;
+  }
+
+ private:
+  enum {
+    kBitFastGet = kFieldInfoBitEnd,
+    kBitFastPut,
+    kIFieldLoweringInfoBitEnd
+  };
+  COMPILE_ASSERT(kIFieldLoweringInfoBitEnd <= 16, too_many_flags);
+  static constexpr uint16_t kFlagFastGet = 1u << kBitFastGet;
+  static constexpr uint16_t kFlagFastPut = 1u << kBitFastPut;
+
+  // The member offset of the field, 0u if unresolved.
+  MemberOffset field_offset_;
+
+  friend class LocalValueNumberingTest;
+};
+
+class MirSFieldLoweringInfo : public MirFieldInfo {
+ public:
+  // For each requested static field retrieve the field's declaring location (dex file, class
+  // index and field index) and volatility and compute the whether we can fast path the access with
+  // IGET/IPUT. For fast path fields (at least for IGET), retrieve the information needed for
+  // the field access, i.e. the field offset, whether the field is in the same class as the
+  // method being compiled, whether the declaring class can be safely assumed to be initialized
+  // and the type index of the declaring class in the compiled method's dex file.
+  static void Resolve(CompilerDriver* compiler_driver, const DexCompilationUnit* mUnit,
+                      MirSFieldLoweringInfo* field_infos, size_t count)
+      LOCKS_EXCLUDED(Locks::mutator_lock_);
+
+  // Construct an unresolved static field lowering info.
+  explicit MirSFieldLoweringInfo(uint16_t field_idx)
+      : MirFieldInfo(field_idx, kFlagIsVolatile | kFlagIsStatic),
+        field_offset_(0u),
+        storage_index_(DexFile::kDexNoIndex) {
+  }
+
+  bool FastGet() const {
+    return (flags_ & kFlagFastGet) != 0u;
+  }
+
+  bool FastPut() const {
+    return (flags_ & kFlagFastPut) != 0u;
+  }
+
+  bool IsReferrersClass() const {
+    return (flags_ & kFlagIsReferrersClass) != 0u;
+  }
+
+  bool IsInitialized() const {
+    return (flags_ & kFlagIsInitialized) != 0u;
+  }
+
+  MemberOffset FieldOffset() const {
+    return field_offset_;
+  }
+
+  uint32_t StorageIndex() const {
+    return storage_index_;
+  }
+
+ private:
+  enum {
+    kBitFastGet = kFieldInfoBitEnd,
+    kBitFastPut,
+    kBitIsReferrersClass,
+    kBitIsInitialized,
+    kSFieldLoweringInfoBitEnd
+  };
+  COMPILE_ASSERT(kSFieldLoweringInfoBitEnd <= 16, too_many_flags);
+  static constexpr uint16_t kFlagFastGet = 1u << kBitFastGet;
+  static constexpr uint16_t kFlagFastPut = 1u << kBitFastPut;
+  static constexpr uint16_t kFlagIsReferrersClass = 1u << kBitIsReferrersClass;
+  static constexpr uint16_t kFlagIsInitialized = 1u << kBitIsInitialized;
+
+  // The member offset of the field, 0u if unresolved.
+  MemberOffset field_offset_;
+  // The type index of the declaring class in the compiling method's dex file,
+  // -1 if the field is unresolved or there's no appropriate TypeId in that dex file.
+  uint32_t storage_index_;
+
+  friend class LocalValueNumberingTest;
+};
+
+}  // namespace art
+
+#endif  // ART_COMPILER_DEX_MIR_FIELD_INFO_H_