[viewcompiler] Add static field get instructions to DexBuilder

This allows us to generate code that can read static fields in a class. Once we
include several other field operations, we will be able to generate more
specialized inflation code in the view compiler.

Bug: 111895153
Change-Id: Ia11195b1cea6d5a3ddbc60d972922586a062c853

6 files changed, 121 insertions, 27 deletions

diff --git a/startop/view_compiler/dex_builder.cc b/startop/view_compiler/dex_builder.cc
index 6047e8c74e38..66bc698e2136 100644
--- a/startop/view_compiler/dex_builder.cc
+++ b/startop/view_compiler/dex_builder.cc
@@ -102,6 +102,9 @@ std::ostream& operator<<(std::ostream& out, const Instruction::Op& opcode) {
     case Instruction::Op::kCheckCast:
       out << "kCheckCast";
       return out;
+    case Instruction::Op::kGetStaticField:
+      out << "kGetStaticField";
+      return out;
   }
 }
 
@@ -229,6 +232,22 @@ ir::Type* DexBuilder::GetOrAddType(const std::string& descriptor) {
   return type;
 }
 
+ir::FieldDecl* DexBuilder::GetOrAddField(TypeDescriptor parent, const std::string& name,
+                                         TypeDescriptor type) {
+  const auto key = std::make_tuple(parent, name);
+  if (field_decls_by_key_.find(key) != field_decls_by_key_.end()) {
+    return field_decls_by_key_[key];
+  }
+
+  ir::FieldDecl* field = Alloc<ir::FieldDecl>();
+  field->parent = GetOrAddType(parent);
+  field->name = GetOrAddString(name);
+  field->type = GetOrAddType(type);
+  dex_file_->fields_map[field->orig_index] = field;
+  field_decls_by_key_[key] = field;
+  return field;
+}
+
 ir::Proto* Prototype::Encode(DexBuilder* dex) const {
   auto* proto = dex->Alloc<ir::Proto>();
   proto->shorty = dex->GetOrAddString(Shorty());
@@ -360,6 +379,8 @@ void MethodBuilder::EncodeInstruction(const Instruction& instruction) {
       return EncodeNew(instruction);
     case Instruction::Op::kCheckCast:
       return EncodeCast(instruction);
+    case Instruction::Op::kGetStaticField:
+      return EncodeStaticFieldOp(instruction);
   }
 }
 
@@ -428,7 +449,7 @@ void MethodBuilder::EncodeInvoke(const Instruction& instruction, ::art::Instruct
     // first move all the arguments into contiguous temporary registers.
     std::array<Value, kMaxArgs> scratch = GetScratchRegisters<kMaxArgs>();
 
-    const auto& prototype = dex_->GetPrototypeByMethodId(instruction.method_id());
+    const auto& prototype = dex_->GetPrototypeByMethodId(instruction.index_argument());
     CHECK(prototype.has_value());
 
     for (size_t i = 0; i < instruction.args().size(); ++i) {
@@ -452,12 +473,12 @@ void MethodBuilder::EncodeInvoke(const Instruction& instruction, ::art::Instruct
 
     Encode3rc(InvokeToInvokeRange(opcode),
               instruction.args().size(),
-              instruction.method_id(),
+              instruction.index_argument(),
               RegisterValue(scratch[0]));
   } else {
     Encode35c(opcode,
               instruction.args().size(),
-              instruction.method_id(),
+              instruction.index_argument(),
               arguments[0],
               arguments[1],
               arguments[2],
@@ -514,6 +535,16 @@ void MethodBuilder::EncodeCast(const Instruction& instruction) {
   Encode21c(::art::Instruction::CHECK_CAST, RegisterValue(*instruction.dest()), type.value());
 }
 
+void MethodBuilder::EncodeStaticFieldOp(const Instruction& instruction) {
+  CHECK_EQ(Instruction::Op::kGetStaticField, instruction.opcode());
+  CHECK(instruction.dest().has_value());
+  CHECK(instruction.dest()->is_variable());
+  CHECK_EQ(0, instruction.args().size());
+
+  Encode21c(
+      ::art::Instruction::SGET, RegisterValue(*instruction.dest()), instruction.index_argument());
+}
+
 size_t MethodBuilder::RegisterValue(const Value& value) const {
   if (value.is_register()) {
     return value.value();
diff --git a/startop/view_compiler/dex_builder.h b/startop/view_compiler/dex_builder.h
index 541d80077bd3..a7ccb4a9452b 100644
--- a/startop/view_compiler/dex_builder.h
+++ b/startop/view_compiler/dex_builder.h
@@ -153,6 +153,7 @@ class Instruction {
     kBranchEqz,
     kBranchNEqz,
     kCheckCast,
+    kGetStaticField,
     kInvokeDirect,
     kInvokeInterface,
     kInvokeStatic,
@@ -170,12 +171,12 @@ class Instruction {
 
   // For instructions with no return value and no arguments.
   static inline Instruction OpNoArgs(Op opcode) {
-    return Instruction{opcode, /*method_id*/ 0, /*dest*/ {}};
+    return Instruction{opcode, /*index_argument*/ 0, /*dest*/ {}};
   }
   // For most instructions, which take some number of arguments and have an optional return value.
   template <typename... T>
   static inline Instruction OpWithArgs(Op opcode, std::optional<const Value> dest, T... args) {
-    return Instruction{opcode, /*method_id=*/0, /*result_is_object=*/false, dest, args...};
+    return Instruction{opcode, /*index_argument=*/0, /*result_is_object=*/false, dest, args...};
   }
 
   // A cast instruction. Basically, `(type)val`
@@ -186,49 +187,54 @@ class Instruction {
 
   // For method calls.
   template <typename... T>
-  static inline Instruction InvokeVirtual(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeVirtual(size_t index_argument, std::optional<const Value> dest,
                                           Value this_arg, T... args) {
     return Instruction{
-        Op::kInvokeVirtual, method_id, /*result_is_object=*/false, dest, this_arg, args...};
+        Op::kInvokeVirtual, index_argument, /*result_is_object=*/false, dest, this_arg, args...};
   }
   // Returns an object
   template <typename... T>
-  static inline Instruction InvokeVirtualObject(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeVirtualObject(size_t index_argument, std::optional<const Value> dest,
                                                 Value this_arg, T... args) {
     return Instruction{
-        Op::kInvokeVirtual, method_id, /*result_is_object=*/true, dest, this_arg, args...};
+        Op::kInvokeVirtual, index_argument, /*result_is_object=*/true, dest, this_arg, args...};
   }
   // For direct calls (basically, constructors).
   template <typename... T>
-  static inline Instruction InvokeDirect(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeDirect(size_t index_argument, std::optional<const Value> dest,
                                          Value this_arg, T... args) {
     return Instruction{
-        Op::kInvokeDirect, method_id, /*result_is_object=*/false, dest, this_arg, args...};
+        Op::kInvokeDirect, index_argument, /*result_is_object=*/false, dest, this_arg, args...};
   }
   // Returns an object
   template <typename... T>
-  static inline Instruction InvokeDirectObject(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeDirectObject(size_t index_argument, std::optional<const Value> dest,
                                                Value this_arg, T... args) {
     return Instruction{
-        Op::kInvokeDirect, method_id, /*result_is_object=*/true, dest, this_arg, args...};
+        Op::kInvokeDirect, index_argument, /*result_is_object=*/true, dest, this_arg, args...};
   }
   // For static calls.
   template <typename... T>
-  static inline Instruction InvokeStatic(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeStatic(size_t index_argument, std::optional<const Value> dest,
                                          T... args) {
-    return Instruction{Op::kInvokeStatic, method_id, /*result_is_object=*/false, dest, args...};
+    return Instruction{Op::kInvokeStatic, index_argument, /*result_is_object=*/false, dest, args...};
   }
   // Returns an object
   template <typename... T>
-  static inline Instruction InvokeStaticObject(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeStaticObject(size_t index_argument, std::optional<const Value> dest,
                                                T... args) {
-    return Instruction{Op::kInvokeStatic, method_id, /*result_is_object=*/true, dest, args...};
+    return Instruction{Op::kInvokeStatic, index_argument, /*result_is_object=*/true, dest, args...};
   }
   // For static calls.
   template <typename... T>
-  static inline Instruction InvokeInterface(size_t method_id, std::optional<const Value> dest,
+  static inline Instruction InvokeInterface(size_t index_argument, std::optional<const Value> dest,
                                             T... args) {
-    return Instruction{Op::kInvokeInterface, method_id, /*result_is_object=*/false, dest, args...};
+    return Instruction{Op::kInvokeInterface, index_argument, /*result_is_object=*/false, dest, args...};
+
+  }
+
+  static inline Instruction GetStaticField(size_t field_id, Value dest) {
+    return Instruction{Op::kGetStaticField, field_id, dest};
   }
 
   ///////////////
@@ -236,27 +242,27 @@ class Instruction {
   ///////////////
 
   Op opcode() const { return opcode_; }
-  size_t method_id() const { return method_id_; }
+  size_t index_argument() const { return index_argument_; }
   bool result_is_object() const { return result_is_object_; }
   const std::optional<const Value>& dest() const { return dest_; }
   const std::vector<const Value>& args() const { return args_; }
 
  private:
-  inline Instruction(Op opcode, size_t method_id, std::optional<const Value> dest)
-      : opcode_{opcode}, method_id_{method_id}, result_is_object_{false}, dest_{dest}, args_{} {}
+  inline Instruction(Op opcode, size_t index_argument, std::optional<const Value> dest)
+      : opcode_{opcode}, index_argument_{index_argument}, result_is_object_{false}, dest_{dest}, args_{} {}
 
   template <typename... T>
-  inline constexpr Instruction(Op opcode, size_t method_id, bool result_is_object,
+  inline constexpr Instruction(Op opcode, size_t index_argument, bool result_is_object,
                                std::optional<const Value> dest, T... args)
       : opcode_{opcode},
-        method_id_{method_id},
+        index_argument_{index_argument},
         result_is_object_{result_is_object},
         dest_{dest},
         args_{args...} {}
 
   const Op opcode_;
   // The index of the method to invoke, for kInvokeVirtual and similar opcodes.
-  const size_t method_id_{0};
+  const size_t index_argument_{0};
   const bool result_is_object_;
   const std::optional<const Value> dest_;
   const std::vector<const Value> args_;
@@ -319,6 +325,7 @@ class MethodBuilder {
   void EncodeBranch(art::Instruction::Code op, const Instruction& instruction);
   void EncodeNew(const Instruction& instruction);
   void EncodeCast(const Instruction& instruction);
+  void EncodeStaticFieldOp(const Instruction& instruction);
 
   // Low-level instruction format encoding. See
   // https://source.android.com/devices/tech/dalvik/instruction-formats for documentation of
@@ -481,6 +488,11 @@ class DexBuilder {
   // See the TypeDescriptor class for help generating these. GetOrAddType can be used to declare
   // imported classes.
   ir::Type* GetOrAddType(const std::string& descriptor);
+  inline ir::Type* GetOrAddType(TypeDescriptor descriptor) {
+    return GetOrAddType(descriptor.descriptor());
+  }
+
+  ir::FieldDecl* GetOrAddField(TypeDescriptor parent, const std::string& name, TypeDescriptor type);
 
   // Returns the method id for the method, creating it if it has not been created yet.
   const MethodDeclData& GetOrDeclareMethod(TypeDescriptor type, const std::string& name,
@@ -526,6 +538,9 @@ class DexBuilder {
 
   // Keep track of already-encoded protos.
   std::map<Prototype, ir::Proto*> proto_map_;
+
+  // Keep track of fields that have been declared
+  std::map<std::tuple<TypeDescriptor, std::string>, ir::FieldDecl*> field_decls_by_key_;
 };
 
 template <typename... T>
diff --git a/startop/view_compiler/dex_builder_test/Android.bp b/startop/view_compiler/dex_builder_test/Android.bp
index ac60e966fe43..9ad1ca1ef48e 100644
--- a/startop/view_compiler/dex_builder_test/Android.bp
+++ b/startop/view_compiler/dex_builder_test/Android.bp
@@ -39,6 +39,7 @@ android_test {
     srcs: [
         "src/android/startop/test/DexBuilderTest.java",
         "src/android/startop/test/LayoutCompilerTest.java",
+        "src/android/startop/test/TestClass.java",
     ],
     sdk_version: "current",
     data: [":generate_dex_testcases", ":generate_compiled_layout1", ":generate_compiled_layout2"],
diff --git a/startop/view_compiler/dex_builder_test/src/android/startop/test/DexBuilderTest.java b/startop/view_compiler/dex_builder_test/src/android/startop/test/DexBuilderTest.java
index 42d4161ee81e..df11bfafd357 100644
--- a/startop/view_compiler/dex_builder_test/src/android/startop/test/DexBuilderTest.java
+++ b/startop/view_compiler/dex_builder_test/src/android/startop/test/DexBuilderTest.java
@@ -28,10 +28,10 @@ import org.junit.Test;
 
 // Adding tests here requires changes in several other places. See README.md in
 // the view_compiler directory for more information.
-public class DexBuilderTest {
+public final class DexBuilderTest {
   static ClassLoader loadDexFile(String filename) throws Exception {
     return new PathClassLoader("/data/local/tmp/dex-builder-test/" + filename,
-        ClassLoader.getSystemClassLoader());
+        DexBuilderTest.class.getClassLoader());
   }
 
   public void hello() {}
@@ -171,4 +171,13 @@ public class DexBuilderTest {
     }
     Assert.assertTrue(castFailed);
   }
+
+  @Test
+  public void readStaticField() throws Exception {
+    ClassLoader loader = loadDexFile("simple.dex");
+    Class clazz = loader.loadClass("android.startop.test.testcases.SimpleTests");
+    Method method = clazz.getMethod("readStaticField");
+    TestClass.staticInteger = 5;
+    Assert.assertEquals(5, method.invoke(null));
+  }
 }
diff --git a/startop/view_compiler/dex_builder_test/src/android/startop/test/TestClass.java b/startop/view_compiler/dex_builder_test/src/android/startop/test/TestClass.java
new file mode 100644
index 000000000000..dd7792306030
--- /dev/null
+++ b/startop/view_compiler/dex_builder_test/src/android/startop/test/TestClass.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+package android.startop.test;
+
+ /**
+ * A simple class to help test DexBuilder.
+ */
+public final class TestClass {
+    public static int staticInteger;
+
+    public int instanceField;
+}
diff --git a/startop/view_compiler/dex_testcase_generator.cc b/startop/view_compiler/dex_testcase_generator.cc
index f62ec5dde85e..5227f8054765 100644
--- a/startop/view_compiler/dex_testcase_generator.cc
+++ b/startop/view_compiler/dex_testcase_generator.cc
@@ -282,6 +282,21 @@ void GenerateSimpleTestCases(const string& outdir) {
     method.Encode();
   }(castObjectToString);
 
+  // Read a static field
+  // integer readStaticField() { return TestClass.staticInteger; }
+  MethodBuilder readStaticField{
+      cbuilder.CreateMethod("readStaticField", Prototype{TypeDescriptor::Int()})};
+  [&](MethodBuilder& method) {
+    const ir::FieldDecl* field =
+        dex_file.GetOrAddField(TypeDescriptor::FromClassname("android.startop.test.TestClass"),
+                               "staticInteger",
+                               TypeDescriptor::Int());
+    Value result{method.MakeRegister()};
+    method.AddInstruction(Instruction::GetStaticField(field->orig_index, result));
+    method.BuildReturn(result, /*is_object=*/false);
+    method.Encode();
+  }(readStaticField);
+
   slicer::MemView image{dex_file.CreateImage()};
   std::ofstream out_file(outdir + "/simple.dex");
   out_file.write(image.ptr<const char>(), image.size());