mirror of
https://gcc.gnu.org/git/gcc.git
synced 2024-11-23 19:03:59 +08:00
b667dd7017
2019-08-14 Martin Liska <mliska@suse.cz> PR sanitizer/89832 PR sanitizer/91325 * All source files: Merge from upstream 368656. From-SVN: r274426
163 lines
7.0 KiB
C++
163 lines
7.0 KiB
C++
//===-- sanitizer_win_defs.h ------------------------------------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Common definitions for Windows-specific code.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#ifndef SANITIZER_WIN_DEFS_H
|
|
#define SANITIZER_WIN_DEFS_H
|
|
|
|
#include "sanitizer_platform.h"
|
|
#if SANITIZER_WINDOWS
|
|
|
|
#ifndef WINAPI
|
|
#if defined(_M_IX86) || defined(__i386__)
|
|
#define WINAPI __stdcall
|
|
#else
|
|
#define WINAPI
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(_M_IX86) || defined(__i386__)
|
|
#define WIN_SYM_PREFIX "_"
|
|
#else
|
|
#define WIN_SYM_PREFIX
|
|
#endif
|
|
|
|
// For MinGW, the /export: directives contain undecorated symbols, contrary to
|
|
// link/lld-link. The GNU linker doesn't support /alternatename and /include
|
|
// though, thus lld-link in MinGW mode interprets them in the same way as
|
|
// in the default mode.
|
|
#ifdef __MINGW32__
|
|
#define WIN_EXPORT_PREFIX
|
|
#else
|
|
#define WIN_EXPORT_PREFIX WIN_SYM_PREFIX
|
|
#endif
|
|
|
|
// Intermediate macro to ensure the parameter is expanded before stringified.
|
|
#define STRINGIFY_(A) #A
|
|
#define STRINGIFY(A) STRINGIFY_(A)
|
|
|
|
// ----------------- A workaround for the absence of weak symbols --------------
|
|
// We don't have a direct equivalent of weak symbols when using MSVC, but we can
|
|
// use the /alternatename directive to tell the linker to default a specific
|
|
// symbol to a specific value.
|
|
// Take into account that this is a pragma directive for the linker, so it will
|
|
// be ignored by the compiler and the function will be marked as UNDEF in the
|
|
// symbol table of the resulting object file. The linker won't find the default
|
|
// implementation until it links with that object file.
|
|
// So, suppose we provide a default implementation "fundef" for "fun", and this
|
|
// is compiled into the object file "test.obj" including the pragma directive.
|
|
// If we have some code with references to "fun" and we link that code with
|
|
// "test.obj", it will work because the linker always link object files.
|
|
// But, if "test.obj" is included in a static library, like "test.lib", then the
|
|
// liker will only link to "test.obj" if necessary. If we only included the
|
|
// definition of "fun", it won't link to "test.obj" (from test.lib) because
|
|
// "fun" appears as UNDEF, so it doesn't resolve the symbol "fun", and will
|
|
// result in a link error (the linker doesn't find the pragma directive).
|
|
// So, a workaround is to force linkage with the modules that include weak
|
|
// definitions, with the following macro: WIN_FORCE_LINK()
|
|
|
|
#define WIN_WEAK_ALIAS(Name, Default) \
|
|
__pragma(comment(linker, "/alternatename:" WIN_SYM_PREFIX STRINGIFY(Name) "="\
|
|
WIN_SYM_PREFIX STRINGIFY(Default)))
|
|
|
|
#define WIN_FORCE_LINK(Name) \
|
|
__pragma(comment(linker, "/include:" WIN_SYM_PREFIX STRINGIFY(Name)))
|
|
|
|
#define WIN_EXPORT(ExportedName, Name) \
|
|
__pragma(comment(linker, "/export:" WIN_EXPORT_PREFIX STRINGIFY(ExportedName)\
|
|
"=" WIN_EXPORT_PREFIX STRINGIFY(Name)))
|
|
|
|
// We cannot define weak functions on Windows, but we can use WIN_WEAK_ALIAS()
|
|
// which defines an alias to a default implementation, and only works when
|
|
// linking statically.
|
|
// So, to define a weak function "fun", we define a default implementation with
|
|
// a different name "fun__def" and we create a "weak alias" fun = fun__def.
|
|
// Then, users can override it just defining "fun".
|
|
// We impose "extern "C"" because otherwise WIN_WEAK_ALIAS() will fail because
|
|
// of name mangling.
|
|
|
|
// Dummy name for default implementation of weak function.
|
|
# define WEAK_DEFAULT_NAME(Name) Name##__def
|
|
// Name for exported implementation of weak function.
|
|
# define WEAK_EXPORT_NAME(Name) Name##__dll
|
|
|
|
// Use this macro when you need to define and export a weak function from a
|
|
// library. For example:
|
|
// WIN_WEAK_EXPORT_DEF(bool, compare, int a, int b) { return a > b; }
|
|
# define WIN_WEAK_EXPORT_DEF(ReturnType, Name, ...) \
|
|
WIN_WEAK_ALIAS(Name, WEAK_DEFAULT_NAME(Name)) \
|
|
WIN_EXPORT(WEAK_EXPORT_NAME(Name), Name) \
|
|
extern "C" ReturnType Name(__VA_ARGS__); \
|
|
extern "C" ReturnType WEAK_DEFAULT_NAME(Name)(__VA_ARGS__)
|
|
|
|
// Use this macro when you need to import a weak function from a library. It
|
|
// defines a weak alias to the imported function from the dll. For example:
|
|
// WIN_WEAK_IMPORT_DEF(compare)
|
|
# define WIN_WEAK_IMPORT_DEF(Name) \
|
|
WIN_WEAK_ALIAS(Name, WEAK_EXPORT_NAME(Name))
|
|
|
|
// So, for Windows we provide something similar to weak symbols in Linux, with
|
|
// some differences:
|
|
// + A default implementation must always be provided.
|
|
//
|
|
// + When linking statically it works quite similarly. For example:
|
|
//
|
|
// // libExample.cc
|
|
// WIN_WEAK_EXPORT_DEF(bool, compare, int a, int b) { return a > b; }
|
|
//
|
|
// // client.cc
|
|
// // We can use the default implementation from the library:
|
|
// compare(1, 2);
|
|
// // Or we can override it:
|
|
// extern "C" bool compare (int a, int b) { return a >= b; }
|
|
//
|
|
// And it will work fine. If we don't override the function, we need to ensure
|
|
// that the linker includes the object file with the default implementation.
|
|
// We can do so with the linker option "-wholearchive:".
|
|
//
|
|
// + When linking dynamically with a library (dll), weak functions are exported
|
|
// with "__dll" suffix. Clients can use the macro WIN_WEAK_IMPORT_DEF(fun)
|
|
// which defines a "weak alias" fun = fun__dll.
|
|
//
|
|
// // libExample.cc
|
|
// WIN_WEAK_EXPORT_DEF(bool, compare, int a, int b) { return a > b; }
|
|
//
|
|
// // client.cc
|
|
// WIN_WEAK_IMPORT_DEF(compare)
|
|
// // We can use the default implementation from the library:
|
|
// compare(1, 2);
|
|
// // Or we can override it:
|
|
// extern "C" bool compare (int a, int b) { return a >= b; }
|
|
//
|
|
// But if we override the function, the dlls don't have access to it (which
|
|
// is different in linux). If that is desired, the strong definition must be
|
|
// exported and interception can be used from the rest of the dlls.
|
|
//
|
|
// // libExample.cc
|
|
// WIN_WEAK_EXPORT_DEF(bool, compare, int a, int b) { return a > b; }
|
|
// // When initialized, check if the main executable defined "compare".
|
|
// int libExample_init() {
|
|
// uptr fnptr = __interception::InternalGetProcAddress(
|
|
// (void *)GetModuleHandleA(0), "compare");
|
|
// if (fnptr && !__interception::OverrideFunction((uptr)compare, fnptr, 0))
|
|
// abort();
|
|
// return 0;
|
|
// }
|
|
//
|
|
// // client.cc
|
|
// WIN_WEAK_IMPORT_DEF(compare)
|
|
// // We override and export compare:
|
|
// extern "C" __declspec(dllexport) bool compare (int a, int b) {
|
|
// return a >= b;
|
|
// }
|
|
//
|
|
#endif // SANITIZER_WINDOWS
|
|
#endif // SANITIZER_WIN_DEFS_H
|