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diff --git a/lib/interception/interception.h b/lib/interception/interception.h
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+//===-- interception.h ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// Machinery for providing replacements/wrappers for system functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef INTERCEPTION_H
+#define INTERCEPTION_H
+
+#if !defined(__linux__) && !defined(__APPLE__) && !defined(_WIN32)
+# error "Interception doesn't work on this operating system."
+#endif
+
+// How to use this library:
+//      1) Include this header to define your own interceptors
+//         (see details below).
+//      2) Build all *.cc files and link against them.
+// On Mac you will also need to:
+//      3) Provide your own implementation for the following functions:
+//           mach_error_t __interception::allocate_island(void **ptr,
+//                                                      size_t size,
+//                                                      void *hint);
+//           mach_error_t __interception::deallocate_island(void *ptr);
+//         See "interception_mac.h" for more details.
+
+// How to add an interceptor:
+// Suppose you need to wrap/replace system function (generally, from libc):
+//      int foo(const char *bar, double baz);
+// You'll need to:
+//      1) define INTERCEPTOR(int, foo, const char *bar, double baz) { ... } in
+//         your source file.
+//      2) Call "INTERCEPT_FUNCTION(foo)" prior to the first call of "foo".
+//         INTERCEPT_FUNCTION(foo) evaluates to "true" iff the function was
+//         intercepted successfully.
+// You can access original function by calling REAL(foo)(bar, baz).
+// By default, REAL(foo) will be visible only inside your interceptor, and if
+// you want to use it in other parts of RTL, you'll need to:
+//      3a) add DECLARE_REAL(int, foo, const char*, double) to a
+//          header file.
+// However, if the call "INTERCEPT_FUNCTION(foo)" and definition for
+// INTERCEPTOR(..., foo, ...) are in different files, you'll instead need to:
+//      3b) add DECLARE_REAL_AND_INTERCEPTOR(int, foo, const char*, double)
+//          to a header file.
+
+// Notes: 1. Things may not work properly if macro INTERCEPT(...) {...} or
+//           DECLARE_REAL(...) are located inside namespaces.
+//        2. On Mac you can also use: "OVERRIDE_FUNCTION(foo, zoo);" to
+//           effectively redirect calls from "foo" to "zoo". In this case
+//           you aren't required to implement
+//           INTERCEPTOR(int, foo, const char *bar, double baz) {...}
+//           but instead you'll have to add
+//           DEFINE_REAL(int, foo, const char *bar, double baz) in your
+//           source file (to define a pointer to overriden function).
+
+// How it works:
+// To replace system functions on Linux we just need to declare functions
+// with same names in our library and then obtain the real function pointers
+// using dlsym().
+// There is one complication. A user may also intercept some of the functions
+// we intercept. To resolve this we declare our interceptors with __interceptor_
+// prefix, and then make actual interceptors weak aliases to __interceptor_
+// functions.
+// This is not so on Mac OS, where the two-level namespace makes
+// our replacement functions invisible to other libraries. This may be overcomed
+// using the DYLD_FORCE_FLAT_NAMESPACE, but some errors loading the shared
+// libraries in Chromium were noticed when doing so. Instead we use
+// mach_override, a handy framework for patching functions at runtime.
+// To avoid possible name clashes, our replacement functions have
+// the "wrap_" prefix on Mac.
+
+#if defined(__APPLE__)
+# define WRAP(x) wrap_##x
+# define WRAPPER_NAME(x) "wrap_"#x
+# define INTERCEPTOR_ATTRIBUTE
+# define DECLARE_WRAPPER(ret_type, convention, func, ...)
+#elif defined(_WIN32)
+# if defined(_DLL)  // DLL CRT
+#  define WRAP(x) x
+#  define WRAPPER_NAME(x) #x
+#  define INTERCEPTOR_ATTRIBUTE
+# else  // Static CRT
+#  define WRAP(x) wrap_##x
+#  define WRAPPER_NAME(x) "wrap_"#x
+#  define INTERCEPTOR_ATTRIBUTE
+# endif
+# define DECLARE_WRAPPER(ret_type, convention, func, ...)
+#else
+# define WRAP(x) __interceptor_ ## x
+# define WRAPPER_NAME(x) "__interceptor_" #x
+# define INTERCEPTOR_ATTRIBUTE __attribute__((visibility("default")))
+# define DECLARE_WRAPPER(ret_type, convention, func, ...) \
+    extern "C" ret_type convention func(__VA_ARGS__) \
+    __attribute__((weak, alias("__interceptor_" #func), visibility("default")));
+#endif
+
+#define PTR_TO_REAL(x) real_##x
+#define REAL(x) __interception::PTR_TO_REAL(x)
+#define FUNC_TYPE(x) x##_f
+
+#define DECLARE_REAL(ret_type, func, ...) \
+  typedef ret_type (*FUNC_TYPE(func))(__VA_ARGS__); \
+  namespace __interception { \
+    extern FUNC_TYPE(func) PTR_TO_REAL(func); \
+  }
+
+#define DECLARE_REAL_AND_INTERCEPTOR(ret_type, func, ...) \
+  DECLARE_REAL(ret_type, func, ##__VA_ARGS__) \
+  extern "C" ret_type WRAP(func)(__VA_ARGS__);
+
+// FIXME(timurrrr): We might need to add DECLARE_REAL_EX etc to support
+// different calling conventions later.
+
+#define DEFINE_REAL_EX(ret_type, convention, func, ...) \
+  typedef ret_type (convention *FUNC_TYPE(func))(__VA_ARGS__); \
+  namespace __interception { \
+    FUNC_TYPE(func) PTR_TO_REAL(func); \
+  }
+
+// Generally, you don't need to use DEFINE_REAL by itself, as INTERCEPTOR
+// macros does its job. In exceptional cases you may need to call REAL(foo)
+// without defining INTERCEPTOR(..., foo, ...). For example, if you override
+// foo with an interceptor for other function.
+#define DEFAULT_CONVENTION
+
+#define DEFINE_REAL(ret_type, func, ...) \
+  DEFINE_REAL_EX(ret_type, DEFAULT_CONVENTION, func, __VA_ARGS__)
+
+#define INTERCEPTOR_EX(ret_type, convention, func, ...) \
+  DEFINE_REAL_EX(ret_type, convention, func, __VA_ARGS__) \
+  DECLARE_WRAPPER(ret_type, convention, func, __VA_ARGS__) \
+  extern "C" \
+  INTERCEPTOR_ATTRIBUTE \
+  ret_type convention WRAP(func)(__VA_ARGS__)
+
+#define INTERCEPTOR(ret_type, func, ...) \
+  INTERCEPTOR_EX(ret_type, DEFAULT_CONVENTION, func, __VA_ARGS__)
+
+#if defined(_WIN32)
+# define INTERCEPTOR_WINAPI(ret_type, func, ...) \
+  INTERCEPTOR_EX(ret_type, __stdcall, func, __VA_ARGS__)
+#endif
+
+#define INCLUDED_FROM_INTERCEPTION_LIB
+
+#if defined(__linux__)
+# include "interception_linux.h"
+# define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_LINUX(func)
+#elif defined(__APPLE__)
+# include "interception_mac.h"
+# define OVERRIDE_FUNCTION(old_func, new_func) \
+    OVERRIDE_FUNCTION_MAC(old_func, new_func)
+# define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_MAC(func)
+#else  // defined(_WIN32)
+# include "interception_win.h"
+# define INTERCEPT_FUNCTION(func) INTERCEPT_FUNCTION_WIN(func)
+#endif
+
+#undef INCLUDED_FROM_INTERCEPTION_LIB
+
+#endif  // INTERCEPTION_H