tsan_external.cpp
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//===-- tsan_external.cpp -------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
//===----------------------------------------------------------------------===//
#include "tsan_rtl.h"
#include "tsan_interceptors.h"
#include "sanitizer_common/sanitizer_ptrauth.h"
namespace __tsan {
#define CALLERPC ((uptr)__builtin_return_address(0))
struct TagData {
const char *object_type;
const char *header;
};
static TagData registered_tags[kExternalTagMax] = {
{},
{"Swift variable", "Swift access race"},
};
static atomic_uint32_t used_tags{kExternalTagFirstUserAvailable};
static TagData *GetTagData(uptr tag) {
// Invalid/corrupted tag? Better return NULL and let the caller deal with it.
if (tag >= atomic_load(&used_tags, memory_order_relaxed)) return nullptr;
return ®istered_tags[tag];
}
const char *GetObjectTypeFromTag(uptr tag) {
TagData *tag_data = GetTagData(tag);
return tag_data ? tag_data->object_type : nullptr;
}
const char *GetReportHeaderFromTag(uptr tag) {
TagData *tag_data = GetTagData(tag);
return tag_data ? tag_data->header : nullptr;
}
void InsertShadowStackFrameForTag(ThreadState *thr, uptr tag) {
FuncEntry(thr, (uptr)®istered_tags[tag]);
}
uptr TagFromShadowStackFrame(uptr pc) {
uptr tag_count = atomic_load(&used_tags, memory_order_relaxed);
void *pc_ptr = (void *)pc;
if (pc_ptr < GetTagData(0) || pc_ptr > GetTagData(tag_count - 1))
return 0;
return (TagData *)pc_ptr - GetTagData(0);
}
#if !SANITIZER_GO
typedef void(*AccessFunc)(ThreadState *, uptr, uptr, int);
void ExternalAccess(void *addr, uptr caller_pc, void *tag, AccessFunc access) {
CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
ThreadState *thr = cur_thread();
if (caller_pc) FuncEntry(thr, caller_pc);
InsertShadowStackFrameForTag(thr, (uptr)tag);
bool in_ignored_lib;
if (!caller_pc || !libignore()->IsIgnored(caller_pc, &in_ignored_lib)) {
access(thr, CALLERPC, (uptr)addr, kSizeLog1);
}
FuncExit(thr);
if (caller_pc) FuncExit(thr);
}
extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE
void *__tsan_external_register_tag(const char *object_type) {
uptr new_tag = atomic_fetch_add(&used_tags, 1, memory_order_relaxed);
CHECK_LT(new_tag, kExternalTagMax);
GetTagData(new_tag)->object_type = internal_strdup(object_type);
char header[127] = {0};
internal_snprintf(header, sizeof(header), "race on %s", object_type);
GetTagData(new_tag)->header = internal_strdup(header);
return (void *)new_tag;
}
SANITIZER_INTERFACE_ATTRIBUTE
void __tsan_external_register_header(void *tag, const char *header) {
CHECK_GE((uptr)tag, kExternalTagFirstUserAvailable);
CHECK_LT((uptr)tag, kExternalTagMax);
atomic_uintptr_t *header_ptr =
(atomic_uintptr_t *)&GetTagData((uptr)tag)->header;
header = internal_strdup(header);
char *old_header =
(char *)atomic_exchange(header_ptr, (uptr)header, memory_order_seq_cst);
if (old_header) internal_free(old_header);
}
SANITIZER_INTERFACE_ATTRIBUTE
void __tsan_external_assign_tag(void *addr, void *tag) {
CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
Allocator *a = allocator();
MBlock *b = nullptr;
if (a->PointerIsMine((void *)addr)) {
void *block_begin = a->GetBlockBegin((void *)addr);
if (block_begin) b = ctx->metamap.GetBlock((uptr)block_begin);
}
if (b) {
b->tag = (uptr)tag;
}
}
SANITIZER_INTERFACE_ATTRIBUTE
void __tsan_external_read(void *addr, void *caller_pc, void *tag) {
ExternalAccess(addr, STRIP_PC(caller_pc), tag, MemoryRead);
}
SANITIZER_INTERFACE_ATTRIBUTE
void __tsan_external_write(void *addr, void *caller_pc, void *tag) {
ExternalAccess(addr, STRIP_PC(caller_pc), tag, MemoryWrite);
}
} // extern "C"
#endif // !SANITIZER_GO
} // namespace __tsan