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[compiler-rt] Fix warnings in interception code 

Summary:
This patch is re-introducing the code to fix the
dynamic hooking on windows and to fix a compiler
warning on Apple.

Related patches:

* https://reviews.llvm.org/D22641
* https://reviews.llvm.org/D22610
* https://reviews.llvm.org/rL276311
* https://reviews.llvm.org/rL276490

Both architecture are using different techniques to
hook on library functions (memchr, strcpy,...). 

On Apple, the function is not dynamically hooked and
the symbol always points to a valid function 
(i.e. can't be null). The REAL macro returns the
symbol.

On windows, the function is dynamically patch and the
REAL(...) function may or may not be null. It depend
on whether or not the function was hooked correctly.
Also, on windows memcpy and memmove are the same.

```
#if !defined(__APPLE__)
[...]
# define REAL(x) __interception::PTR_TO_REAL(x)
# define ASSIGN_REAL(dst, src) REAL(dst) = REAL(src)
[...]
#else  // __APPLE__
[...]
# define REAL(x) x
# define ASSIGN_REAL(x, y)
[...]
#endif  // __APPLE__

Reviewers: rnk

Subscribers: kcc, hans, kubabrecka, llvm-commits, bruno, chrisha

Differential Revision: https://reviews.llvm.org/D22758

llvm-svn: 276885
This commit is contained in:
Etienne Bergeron 2016-07-27 16:16:54 +00:00
parent 271ca40118
commit 8c6eb1566c
4 changed files with 12 additions and 2 deletions
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6
compiler-rt/lib/asan/asan_interceptors.cc
View File

@ -725,11 +725,13 @@ void InitializeAsanInterceptors() {
InitializeCommonInterceptors();
// Intercept mem* functions.
ASAN_INTERCEPT_FUNC(memcpy);
ASAN_INTERCEPT_FUNC(memmove);
ASAN_INTERCEPT_FUNC(memset);
if (PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE) {
// In asan, REAL(memmove) is not used, but it is used in msan.
ASAN_INTERCEPT_FUNC(memmove);
ASAN_INTERCEPT_FUNC(memcpy);
} else {
ASSIGN_REAL(memcpy, memmove);
}
CHECK(REAL(memcpy));

2
compiler-rt/lib/asan/tests/asan_str_test.cc
View File

@ -457,11 +457,13 @@ TEST(AddressSanitizer, StrArgsOverlapTest) {
#if !defined(__APPLE__) || !defined(MAC_OS_X_VERSION_10_7) || \
(MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7)
// Check "memcpy". Use Ident() to avoid inlining.
#if PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE
memset(str, 'z', size);
Ident(memcpy)(str + 1, str + 11, 10);
Ident(memcpy)(str, str, 0);
EXPECT_DEATH(Ident(memcpy)(str, str + 14, 15), OverlapErrorMessage("memcpy"));
EXPECT_DEATH(Ident(memcpy)(str + 14, str, 15), OverlapErrorMessage("memcpy"));
#endif
#endif
// We do not treat memcpy with to==from as a bug.

2
compiler-rt/lib/interception/interception.h
View File

@ -158,10 +158,12 @@ const interpose_substitution substitution_##func_name[] \
namespace __interception { \
extern FUNC_TYPE(func) PTR_TO_REAL(func); \
}
# define ASSIGN_REAL(dst, src) REAL(dst) = REAL(src)
#else // __APPLE__
# define REAL(x) x
# define DECLARE_REAL(ret_type, func, ...) \
extern "C" ret_type func(__VA_ARGS__);
# define ASSIGN_REAL(x, y)
#endif // __APPLE__
#define DECLARE_REAL_AND_INTERCEPTOR(ret_type, func, ...) \

4
compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
View File

@ -663,12 +663,16 @@ INTERCEPTOR(void*, memchr, const void *s, int c, SIZE_T n) {
return internal_memchr(s, c, n);
void *ctx;
COMMON_INTERCEPTOR_ENTER(ctx, memchr, s, c, n);
#if SANITIZER_WINDOWS
void *res;
if (REAL(memchr)) {
res = REAL(memchr)(s, c, n);
} else {
res = internal_memchr(s, c, n);
}
#else
void *res = REAL(memchr)(s, c, n);
#endif
uptr len = res ? (char *)res - (const char *)s + 1 : n;
COMMON_INTERCEPTOR_READ_RANGE(ctx, s, len);
return res;