libsanitizer/tsan/tsan_external.cc

   1 //===-- tsan_external.cc --------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 //===----------------------------------------------------------------------===//
  11 #include "tsan_rtl.h"
  12 #include "tsan_interceptors.h"
  13
  14 namespace __tsan {
  15
  16 #define CALLERPC ((uptr)__builtin_return_address(0))
  17
  18 struct TagData {
  19   const char *object_type;
  20   const char *header;
  21 };
  22
  23 static TagData registered_tags[kExternalTagMax] = {
  24   {},
  25   {"Swift variable", "Swift access race"},
  26 };
  27 static atomic_uint32_t used_tags{kExternalTagFirstUserAvailable};  // NOLINT.
  28 static TagData *GetTagData(uptr tag) {
  29   // Invalid/corrupted tag?  Better return NULL and let the caller deal with it.
  30   if (tag >= atomic_load(&used_tags, memory_order_relaxed)) return nullptr;
  31   return &registered_tags[tag];
  32 }
  33
  34 const char *GetObjectTypeFromTag(uptr tag) {
  35   TagData *tag_data = GetTagData(tag);
  36   return tag_data ? tag_data->object_type : nullptr;
  37 }
  38
  39 const char *GetReportHeaderFromTag(uptr tag) {
  40   TagData *tag_data = GetTagData(tag);
  41   return tag_data ? tag_data->header : nullptr;
  42 }
  43
  44 void InsertShadowStackFrameForTag(ThreadState *thr, uptr tag) {
  45   FuncEntry(thr, (uptr)&registered_tags[tag]);
  46 }
  47
  48 uptr TagFromShadowStackFrame(uptr pc) {
  49   uptr tag_count = atomic_load(&used_tags, memory_order_relaxed);
  50   void *pc_ptr = (void *)pc;
  51   if (pc_ptr < GetTagData(0) || pc_ptr > GetTagData(tag_count - 1))
  52     return 0;
  53   return (TagData *)pc_ptr - GetTagData(0);
  54 }
  55
  56 #if !SANITIZER_GO
  57
  58 typedef void(*AccessFunc)(ThreadState *, uptr, uptr, int);
  59 void ExternalAccess(void *addr, void *caller_pc, void *tag, AccessFunc access) {
  60   CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
  61   ThreadState *thr = cur_thread();
  62   if (caller_pc) FuncEntry(thr, (uptr)caller_pc);
  63   InsertShadowStackFrameForTag(thr, (uptr)tag);
  64   bool in_ignored_lib;
  65   if (!caller_pc || !libignore()->IsIgnored((uptr)caller_pc, &in_ignored_lib)) {
  66     access(thr, CALLERPC, (uptr)addr, kSizeLog1);
  67   }
  68   FuncExit(thr);
  69   if (caller_pc) FuncExit(thr);
  70 }
  71
  72 extern "C" {
  73 SANITIZER_INTERFACE_ATTRIBUTE
  74 void *__tsan_external_register_tag(const char *object_type) {
  75   uptr new_tag = atomic_fetch_add(&used_tags, 1, memory_order_relaxed);
  76   CHECK_LT(new_tag, kExternalTagMax);
  77   GetTagData(new_tag)->object_type = internal_strdup(object_type);
  78   char header[127] = {0};
  79   internal_snprintf(header, sizeof(header), "race on %s", object_type);
  80   GetTagData(new_tag)->header = internal_strdup(header);
  81   return (void *)new_tag;
  82 }
  83
  84 SANITIZER_INTERFACE_ATTRIBUTE
  85 void __tsan_external_register_header(void *tag, const char *header) {
  86   CHECK_GE((uptr)tag, kExternalTagFirstUserAvailable);
  87   CHECK_LT((uptr)tag, kExternalTagMax);
  88   atomic_uintptr_t *header_ptr =
  89       (atomic_uintptr_t *)&GetTagData((uptr)tag)->header;
  90   header = internal_strdup(header);
  91   char *old_header =
  92       (char *)atomic_exchange(header_ptr, (uptr)header, memory_order_seq_cst);
  93   if (old_header) internal_free(old_header);
  94 }
  95
  96 SANITIZER_INTERFACE_ATTRIBUTE
  97 void __tsan_external_assign_tag(void *addr, void *tag) {
  98   CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
  99   Allocator *a = allocator();
 100   MBlock *b = nullptr;
 101   if (a->PointerIsMine((void *)addr)) {
 102     void *block_begin = a->GetBlockBegin((void *)addr);
 103     if (block_begin) b = ctx->metamap.GetBlock((uptr)block_begin);
 104   }
 105   if (b) {
 106     b->tag = (uptr)tag;
 107   }
 108 }
 109
 110 SANITIZER_INTERFACE_ATTRIBUTE
 111 void __tsan_external_read(void *addr, void *caller_pc, void *tag) {
 112   ExternalAccess(addr, caller_pc, tag, MemoryRead);
 113 }
 114
 115 SANITIZER_INTERFACE_ATTRIBUTE
 116 void __tsan_external_write(void *addr, void *caller_pc, void *tag) {
 117   ExternalAccess(addr, caller_pc, tag, MemoryWrite);
 118 }
 119 }  // extern "C"
 120
 121 #endif  // !SANITIZER_GO
 122
 123 }  // namespace __tsan