Add a host tool to pack R_ARM_RELATIVE relocations in libchrome.<ver>.so.

tools/relocation_packer/src/relocation_packer_debug.h

Index: tools/relocation_packer/src/relocation_packer_debug.h
diff --git a/tools/relocation_packer/src/relocation_packer_debug.h b/tools/relocation_packer/src/relocation_packer_debug.h
new file mode 100644
index 0000000000000000000000000000000000000000..220ac0ae66d53c3138e9dfde548008a612332593
--- /dev/null
+++ b/tools/relocation_packer/src/relocation_packer_debug.h
@@ -0,0 +1,81 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Logging and checks.
+//
+// Log messages to stdout.  LOG() prints normal user messages, VLOG)

[rmcilroy, 2014/06/02 15:16:35]

VLOG()

[simonb (inactive), 2014/06/04 16:40:35]

Done.

+// is verbose, for tracing and debugging.  SetVerbose() enables/disables
+// VLOG() output.
+//
+// LOG() and VLOG() are printf-like, and arguments are checked by gcc.
+// LOG_IF() and VLOG_IF() call LOG/VLOG if their predicate is true.
+// CHECK() aborts if its predicate is false.  NOTREACHED() always aborts.
+//
+
+#ifndef RELOCATION_PACKER_DEBUG_H
+#define RELOCATION_PACKER_DEBUG_H
+
+#undef NDEBUG

[rmcilroy, 2014/06/02 15:16:35]

I don't think you should be undef'ing NDEBUG in a header.  If you are doing this
in order to get assert defined to do something even if NDEBUG is set, then you
could do what /base does (cause a DebuggerBreak if Check fails), or only undef
NDEBUG while importing assert.h.

[simonb (inactive), 2014/06/04 16:40:35]

Done.

+#include <assert.h>
+#include <stdarg.h>
+#include <string.h>
+
+namespace relocation_packer {
+
+// If gcc, define PRINTF_ATTRIBUTE so that gcc checks Log() as printf-like.
+#if defined(__GNUC__) && (__GNUC__ >= 3)
+#define PRINTF_ATTRIBUTE(string_index, first_to_check) \
+    __attribute__((__format__(__printf__, string_index, first_to_check)))
+#else
+#define PRINTF_ATTRIBUTE(string_index, first_to_check)
+#endif
+
+// Logging and checking macros.
+#define LOG(...) ::relocation_packer::Logger::Log(__VA_ARGS__)
+#define VLOG(...) ::relocation_packer::Logger::VLog(__VA_ARGS__)
+#define LOG_IF(cond, ...)  \
+  do {                     \
+    if ((cond))            \
+      LOG(__VA_ARGS__);    \
+  } while (0)
+#define VLOG_IF(cond, ...) \
+  do {                     \
+    if ((cond))            \
+      VLOG(__VA_ARGS__);   \
+  } while (0)
+
+#define CHECK(expr) assert((expr))
+#define NOTREACHED(_) assert(false)
+
+class Logger {
+ public:
+  // Log and verbose log to stdout.
+  // |format| is a printf format string.
+  static void Log(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
+  static void VLog(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
+
+  // Set verbose mode.
+  // |flag| is true to enable verbose logging, false to disable it.
+  static void SetVerbose(bool flag);
+
+ private:
+  Logger() { ::memset(this, 0, sizeof(*this)); }

[rmcilroy, 2014/06/02 15:16:35]

no need for "::" global namespace prefix (throughout CL).  In this particulary
instance I think it would be clearer just to explicitly set
"is_verbose_(false)".

[simonb (inactive), 2014/06/04 16:40:35]

Done.

+  ~Logger() {}
+
+  // Implementation of log to stdout.
+  // |format| is a printf format string.
+  // |args| is a varargs list of printf arguments.
+  void Log(const char* format, va_list args);
+
+  // If set, VLOG is enabled, otherwise it is a no-op.
+  bool is_verbose_;
+
+  // Singleton support.
+  static Logger* GetInstance();
+  static Logger* instance_;
+};
+
+}  // namespace relocation_packer
+
+#endif  // RELOCATION_PACKER_DEBUG_H