runtime: Refactor asm_support to be auto-generated (mostly)

Usage:

* If the defines are no longer up to date, re-run generate-asm-support

* To add a new field:
--- Edit one of the offset_ or constant def files.
--- Rebuild cpp-define-generator and re-run generate-asm-support

Change-Id: I772430fcf1ad9af40898ebb453848f8412612386
TODO: Integrate this into the build somehow
TODO: Account for 32 vs 64-bit and read barrier vs no read barrier
diff --git a/tools/cpp-define-generator/main.cc b/tools/cpp-define-generator/main.cc
new file mode 100644
index 0000000..a1b463a
--- /dev/null
+++ b/tools/cpp-define-generator/main.cc
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include <iostream>
+#include <sstream>
+#include <type_traits>
+#include <ios>
+#include <algorithm>
+#include <string>
+
+// Art Offset file dependencies
+#define DEFINE_INCLUDE_DEPENDENCIES
+#include "offsets_all.def"
+
+std::string to_upper(std::string input) {
+  std::transform(input.begin(), input.end(), input.begin(), ::toupper);
+  return input;
+}
+
+template <typename T, typename = void>
+typename std::enable_if<!std::is_signed<T>::value, std::string>::type
+pretty_format(T value) {
+  // Print most values as hex.
+  std::stringstream ss;
+  ss << std::showbase << std::hex << value;
+  return ss.str();
+}
+
+template <typename T, typename = void>
+typename std::enable_if<std::is_signed<T>::value, std::string>::type
+pretty_format(T value) {
+  // Print "signed" values as decimal so that the negativity doesn't get lost.
+  std::stringstream ss;
+
+  // For negative values add a (). Omit it from positive values for conciseness.
+  if (value < 0) {
+    ss << "(";
+  }
+
+  ss << value;
+
+  if (value < 0) {
+    ss << ")";
+  }
+  return ss.str();
+}
+
+template <typename T>
+void cpp_define(std::string name, T value) {
+  std::cout << "#define " << name << " " << pretty_format(value) << std::endl;
+}
+
+template <typename T>
+void emit_check_eq(T value, std::string expr) {
+  std::cout << "DEFINE_CHECK_EQ(" << value << ", (" << expr << "))" << std::endl;
+}
+
+const char *kFileHeader = /* // NOLINT [readability/multiline_string] [5] */ R"L1C3NS3(
+/*
+ * Copyright (C) 2016 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_RUNTIME_GENERATED_ASM_SUPPORT_GEN_H_
+#define ART_RUNTIME_GENERATED_ASM_SUPPORT_GEN_H_
+
+// This file has been auto-generated by cpp-define-generator; do not edit directly.
+)L1C3NS3";  // NOLINT [readability/multiline_string] [5]
+
+const char *kFileFooter = /* // NOLINT [readability/multiline_string] [5] */ R"F00T3R(
+#endif  // ART_RUNTIME_GENERATED_ASM_SUPPORT_GEN_H_
+)F00T3R";  // NOLINT [readability/multiline_string] [5]
+
+#define MACROIZE(holder_type, field_name) to_upper(#holder_type "_" #field_name "_OFFSET")
+
+int main() {
+  std::cout << kFileHeader << std::endl;
+
+  std::string z = "";
+
+  // Print every constant expression to stdout as a #define or a CHECK_EQ
+#define DEFINE_EXPR(macro_name, field_type, expr) \
+  cpp_define(to_upper(#macro_name), static_cast<field_type>(expr)); \
+  emit_check_eq(z + "static_cast<" #field_type ">(" + to_upper(#macro_name) + ")", \
+                "static_cast<" #field_type ">(" #expr ")");
+#include "offsets_all.def"
+
+  std::cout << kFileFooter << std::endl;
+  return 0;
+}