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[libsanitizer, Darwin] Fix bootstrap after recent merge.

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The latest merge to libsanitizer includes changes to handle macOS 13+.
However, these changes are incompatible with GCC and so we need to find
an alternate solution.  To restore bootstrap back this change out until
the alternate can be found.
This commit is contained in:
Iain Sandoe 2022-09-04 20:22:21 +01:00
parent 8293a9632c
commit af9587ff0f
1 changed files with 10 additions and 52 deletions
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62
libsanitizer/sanitizer_common/sanitizer_procmaps_mac.cpp
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@ -146,8 +146,13 @@ static bool IsDyldHdr(const mach_header *hdr) {
// until we hit a Mach header matching dyld instead. These recurse
// calls are expensive, but the first memory map generation occurs
// early in the process, when dyld is one of the only images loaded,
// so it will be hit after only a few iterations. These assumptions don't hold
// on macOS 13+ anymore (dyld itself has moved into the shared cache).
// so it will be hit after only a few iterations. These assumptions don't
// hold on macOS 13+ anymore (dyld itself has moved into the shared cache).
// FIXME: Unfortunately, the upstream revised version to deal with macOS 13+
// is incompatible with GCC and also uses APIs not available on earlier
// systems which we support; backed out for now.
static mach_header *GetDyldImageHeaderViaVMRegion() {
vm_address_t address = 0;
@ -171,64 +176,17 @@ static mach_header *GetDyldImageHeaderViaVMRegion() {
}
}
extern "C" {
struct dyld_shared_cache_dylib_text_info {
uint64_t version; // current version 2
// following fields all exist in version 1
uint64_t loadAddressUnslid;
uint64_t textSegmentSize;
uuid_t dylibUuid;
const char *path; // pointer invalid at end of iterations
// following fields all exist in version 2
uint64_t textSegmentOffset; // offset from start of cache
};
typedef struct dyld_shared_cache_dylib_text_info
dyld_shared_cache_dylib_text_info;
extern bool _dyld_get_shared_cache_uuid(uuid_t uuid);
extern const void *_dyld_get_shared_cache_range(size_t *length);
extern int dyld_shared_cache_iterate_text(
const uuid_t cacheUuid,
void (^callback)(const dyld_shared_cache_dylib_text_info *info));
} // extern "C"
static mach_header *GetDyldImageHeaderViaSharedCache() {
uuid_t uuid;
bool hasCache = _dyld_get_shared_cache_uuid(uuid);
if (!hasCache)
return nullptr;
size_t cacheLength;
__block uptr cacheStart = (uptr)_dyld_get_shared_cache_range(&cacheLength);
CHECK(cacheStart && cacheLength);
__block mach_header *dyldHdr = nullptr;
int res = dyld_shared_cache_iterate_text(
uuid, ^(const dyld_shared_cache_dylib_text_info *info) {
CHECK_GE(info->version, 2);
mach_header *hdr =
(mach_header *)(cacheStart + info->textSegmentOffset);
if (IsDyldHdr(hdr))
dyldHdr = hdr;
});
CHECK_EQ(res, 0);
return dyldHdr;
}
const mach_header *get_dyld_hdr() {
if (!dyld_hdr) {
// On macOS 13+, dyld itself has moved into the shared cache. Looking it up
// via vm_region_recurse_64() causes spins/hangs/crashes.
// FIXME: find a way to do this compatible with GCC.
if (GetMacosAlignedVersion() >= MacosVersion(13, 0)) {
dyld_hdr = GetDyldImageHeaderViaSharedCache();
if (!dyld_hdr) {
VReport(1,
"Failed to lookup the dyld image header in the shared cache on "
"macOS 13+ (or no shared cache in use). Falling back to "
"looking up the dyld image header in the shared cache on "
"macOS 13+ is not yet supported. Falling back to "
"lookup via vm_region_recurse_64().\n");
dyld_hdr = GetDyldImageHeaderViaVMRegion();
}
} else {
dyld_hdr = GetDyldImageHeaderViaVMRegion();
}