Move startop/tools/view_compiler to startop/view_compiler

This is planned to ship on device, so by convention the view_compiler should not
be in a tools directory.

Change-Id: I0eb03812d77ec38edc3908725acb40bacb345ecd

1 files changed, 189 insertions, 0 deletions

diff --git a/startop/view_compiler/dex_builder.h b/startop/view_compiler/dex_builder.h
new file mode 100644
index 000000000000..d280abce21f5
--- /dev/null
+++ b/startop/view_compiler/dex_builder.h
@@ -0,0 +1,189 @@
+/*
+ * 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.
+ */
+#ifndef DEX_BUILDER_H_
+#define DEX_BUILDER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "slicer/dex_ir.h"
+#include "slicer/writer.h"
+
+namespace startop {
+namespace dex {
+
+// TODO: remove this once the dex generation code is complete.
+void WriteTestDexFile(const std::string& filename);
+
+//////////////////////////
+// Forward declarations //
+//////////////////////////
+class DexBuilder;
+
+// Our custom allocator for dex::Writer
+//
+// This keeps track of all allocations and ensures they are freed when
+// TrackingAllocator is destroyed. Pointers to memory allocated by this
+// allocator must not outlive the allocator.
+class TrackingAllocator : public ::dex::Writer::Allocator {
+ public:
+  virtual void* Allocate(size_t size);
+  virtual void Free(void* ptr);
+
+ private:
+  std::map<void*, std::unique_ptr<uint8_t[]>> allocations_;
+};
+
+// Represents a DEX type descriptor.
+//
+// TODO: add a way to create a descriptor for a reference of a class type.
+class TypeDescriptor {
+ public:
+  // Named constructors for base type descriptors.
+  static const TypeDescriptor Int();
+  static const TypeDescriptor Void();
+
+  // Return the full descriptor, such as I or Ljava/lang/Object
+  const std::string& descriptor() const { return descriptor_; }
+  // Return the shorty descriptor, such as I or L
+  std::string short_descriptor() const { return descriptor().substr(0, 1); }
+
+ private:
+  TypeDescriptor(std::string descriptor) : descriptor_{descriptor} {}
+
+  const std::string descriptor_;
+};
+
+// Defines a function signature. For example, Prototype{TypeDescriptor::VOID, TypeDescriptor::Int}
+// represents the function type (Int) -> Void.
+class Prototype {
+ public:
+  template <typename... TypeDescriptors>
+  Prototype(TypeDescriptor return_type, TypeDescriptors... param_types)
+      : return_type_{return_type}, param_types_{param_types...} {}
+
+  // Encode this prototype into the dex file.
+  ir::Proto* Encode(DexBuilder* dex) const;
+
+  // Get the shorty descriptor, such as VII for (Int, Int) -> Void
+  std::string Shorty() const;
+
+ private:
+  const TypeDescriptor return_type_;
+  const std::vector<TypeDescriptor> param_types_;
+};
+
+// Tools to help build methods and their bodies.
+class MethodBuilder {
+ public:
+  MethodBuilder(DexBuilder* dex, ir::Class* class_def, ir::MethodDecl* decl);
+
+  // Encode the method into DEX format.
+  ir::EncodedMethod* Encode();
+
+  // Registers are just represented by their number.
+  using Register = size_t;
+
+  // Create a new register to be used to storing values. Note that these are not SSA registers, like
+  // might be expected in similar code generators. This does no liveness tracking or anything, so
+  // it's up to the caller to reuse registers as appropriate.
+  Register MakeRegister();
+
+  /////////////////////////////////
+  // Instruction builder methods //
+  /////////////////////////////////
+
+  // return-void
+  void BuildReturn();
+  void BuildReturn(Register src);
+  // const/4
+  void BuildConst4(Register target, int value);
+
+  // TODO: add builders for more instructions
+
+ private:
+  DexBuilder* dex_;
+  ir::Class* class_;
+  ir::MethodDecl* decl_;
+
+  // A buffer to hold instructions we are generating.
+  std::vector<::dex::u2> buffer_;
+
+  // How many registers we've allocated
+  size_t num_registers_;
+};
+
+// A helper to build class definitions.
+class ClassBuilder {
+ public:
+  ClassBuilder(DexBuilder* parent, ir::Class* class_def);
+
+  void set_source_file(const std::string& source);
+
+  // Create a method with the given name and prototype. The returned MethodBuilder can be used to
+  // fill in the method body.
+  MethodBuilder CreateMethod(const std::string& name, Prototype prototype);
+
+ private:
+  DexBuilder* parent_;
+  ir::Class* class_;
+};
+
+// Builds Dex files from scratch.
+class DexBuilder {
+ public:
+  DexBuilder();
+
+  // Create an in-memory image of the DEX file that can either be loaded directly or written to a
+  // file.
+  slicer::MemView CreateImage();
+
+  template <typename T>
+  T* Alloc() {
+    return dex_file_->Alloc<T>();
+  }
+
+  // Find the ir::String that matches the given string, creating it if it does not exist.
+  ir::String* GetOrAddString(const std::string& string);
+  // Create a new class of the given name.
+  ClassBuilder MakeClass(const std::string& name);
+
+  // Add a type for the given descriptor, or return the existing one if it already exists.
+  // See the TypeDescriptor class for help generating these.
+  ir::Type* GetOrAddType(const std::string& descriptor);
+
+ private:
+  std::shared_ptr<ir::DexFile> dex_file_;
+
+  // allocator_ is needed to be able to encode the image.
+  TrackingAllocator allocator_;
+
+  // We'll need to allocate buffers for all of the encoded strings we create. This is where we store
+  // all of them.
+  std::vector<std::unique_ptr<uint8_t[]>> string_data_;
+
+  // Keep track of what types we've defined so we can look them up later.
+  std::map<std::string, ir::Type*> types_by_descriptor_;
+
+  // Keep track of what strings we've defined so we can look them up later.
+  std::map<std::string, ir::String*> strings_;
+};
+
+}  // namespace dex
+}  // namespace startop
+
+#endif  // DEX_BUILDER_H_