Improve HLoadClass code generation.

For classes in the boot image, use either direct pointers
or PC-relative addresses. For other classes, use PC-relative
access to the dex cache arrays for AOT and direct address of
the type's dex cache slot for JIT.

For aosp_flounder-userdebug:
  - 32-bit boot.oat: -252KiB (-0.3%)
  - 64-bit boot.oat: -412KiB (-0.4%)
  - 32-bit dalvik cache total: -392KiB (-0.4%)
  - 64-bit dalvik-cache total: -2312KiB (-1.0%)
    (contains more files than the 32-bit dalvik cache)
For aosp_flounder-userdebug forced to compile PIC:
  - 32-bit boot.oat: -124KiB (-0.2%)
  - 64-bit boot.oat: -420KiB (-0.5%)
  - 32-bit dalvik cache total: -136KiB (-0.1%)
  - 64-bit dalvik-cache total: -1136KiB (-0.5%)
    (contains more files than the 32-bit dalvik cache)

Bug: 27950288
Change-Id: I4da991a4b7e53c63c92558b97923d18092acf139

1 files changed, 20 insertions, 1 deletions

diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index 82a54d2ed1..81c1a7fe16 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -449,10 +449,15 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
                              SlowPathCode* slow_path) = 0;
 
   // Check if the desired_string_load_kind is supported. If it is, return it,
-  // otherwise return a fall-back info that should be used instead.
+  // otherwise return a fall-back kind that should be used instead.
   virtual HLoadString::LoadKind GetSupportedLoadStringKind(
       HLoadString::LoadKind desired_string_load_kind) = 0;
 
+  // Check if the desired_class_load_kind is supported. If it is, return it,
+  // otherwise return a fall-back kind that should be used instead.
+  virtual HLoadClass::LoadKind GetSupportedLoadClassKind(
+      HLoadClass::LoadKind desired_class_load_kind) = 0;
+
   // Check if the desired_dispatch_info is supported. If it is, return it,
   // otherwise return a fall-back info that should be used instead.
   virtual HInvokeStaticOrDirect::DispatchInfo GetSupportedInvokeStaticOrDirectDispatch(
@@ -496,6 +501,20 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
     LabelType label;
   };
 
+  // Type patch info used for recording locations of required linker patches and
+  // target types. The actual type address can be absolute or PC-relative.
+  // TODO: Consider merging with MethodPatchInfo and StringPatchInfo - all these
+  // classes contain the dex file, some index and the label.
+  template <typename LabelType>
+  struct TypePatchInfo {
+    TypePatchInfo(const DexFile& df, uint32_t index)
+        : dex_file(df), type_index(index), label() { }
+
+    const DexFile& dex_file;
+    uint32_t type_index;
+    LabelType label;
+  };
+
   CodeGenerator(HGraph* graph,
                 size_t number_of_core_registers,
                 size_t number_of_fpu_registers,