contrib/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep_new.cc

   1 //===-- sanitizer_coverage_libcdep_new.cc ---------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 // Sanitizer Coverage Controller for Trace PC Guard.
  10
  11 #include "sanitizer_platform.h"
  12
  13 #if !SANITIZER_FUCHSIA
  14 #include "sancov_flags.h"
  15 #include "sanitizer_allocator_internal.h"
  16 #include "sanitizer_atomic.h"
  17 #include "sanitizer_common.h"
  18 #include "sanitizer_file.h"
  19
  20 using namespace __sanitizer;
  21
  22 using AddressRange = LoadedModule::AddressRange;
  23
  24 namespace __sancov {
  25 namespace {
  26
  27 static const u64 Magic64 = 0xC0BFFFFFFFFFFF64ULL;
  28 static const u64 Magic32 = 0xC0BFFFFFFFFFFF32ULL;
  29 static const u64 Magic = SANITIZER_WORDSIZE == 64 ? Magic64 : Magic32;
  30
  31 static fd_t OpenFile(const char* path) {
  32   error_t err;
  33   fd_t fd = OpenFile(path, WrOnly, &err);
  34   if (fd == kInvalidFd)
  35     Report("SanitizerCoverage: failed to open %s for writing (reason: %d)\n",
  36            path, err);
  37   return fd;
  38 }
  39
  40 static void GetCoverageFilename(char* path, const char* name,
  41                                 const char* extension) {
  42   CHECK(name);
  43   internal_snprintf(path, kMaxPathLength, "%s/%s.%zd.%s",
  44                     common_flags()->coverage_dir, name, internal_getpid(),
  45                     extension);
  46 }
  47
  48 static void WriteModuleCoverage(char* file_path, const char* module_name,
  49                                 const uptr* pcs, uptr len) {
  50   GetCoverageFilename(file_path, StripModuleName(module_name), "sancov");
  51   fd_t fd = OpenFile(file_path);
  52   WriteToFile(fd, &Magic, sizeof(Magic));
  53   WriteToFile(fd, pcs, len * sizeof(*pcs));
  54   CloseFile(fd);
  55   Printf("SanitizerCoverage: %s: %zd PCs written\n", file_path, len);
  56 }
  57
  58 static void SanitizerDumpCoverage(const uptr* unsorted_pcs, uptr len) {
  59   if (!len) return;
  60
  61   char* file_path = static_cast<char*>(InternalAlloc(kMaxPathLength));
  62   char* module_name = static_cast<char*>(InternalAlloc(kMaxPathLength));
  63   uptr* pcs = static_cast<uptr*>(InternalAlloc(len * sizeof(uptr)));
  64
  65   internal_memcpy(pcs, unsorted_pcs, len * sizeof(uptr));
  66   Sort(pcs, len);
  67
  68   bool module_found = false;
  69   uptr last_base = 0;
  70   uptr module_start_idx = 0;
  71
  72   for (uptr i = 0; i < len; ++i) {
  73     const uptr pc = pcs[i];
  74     if (!pc) continue;
  75
  76     if (!__sanitizer_get_module_and_offset_for_pc(pc, nullptr, 0, &pcs[i])) {
  77       Printf("ERROR: unknown pc 0x%x (may happen if dlclose is used)\n", pc);
  78       continue;
  79     }
  80     uptr module_base = pc - pcs[i];
  81
  82     if (module_base != last_base || !module_found) {
  83       if (module_found) {
  84         WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  85                             i - module_start_idx);
  86       }
  87
  88       last_base = module_base;
  89       module_start_idx = i;
  90       module_found = true;
  91       __sanitizer_get_module_and_offset_for_pc(pc, module_name, kMaxPathLength,
  92                                                &pcs[i]);
  93     }
  94   }
  95
  96   if (module_found) {
  97     WriteModuleCoverage(file_path, module_name, &pcs[module_start_idx],
  98                         len - module_start_idx);
  99   }
 100
 101   InternalFree(file_path);
 102   InternalFree(module_name);
 103   InternalFree(pcs);
 104 }
 105
 106 // Collects trace-pc guard coverage.
 107 // This class relies on zero-initialization.
 108 class TracePcGuardController {
 109  public:
 110   void Initialize() {
 111     CHECK(!initialized);
 112
 113     initialized = true;
 114     InitializeSancovFlags();
 115
 116     pc_vector.Initialize(0);
 117   }
 118
 119   void InitTracePcGuard(u32* start, u32* end) {
 120     if (!initialized) Initialize();
 121     CHECK(!*start);
 122     CHECK_NE(start, end);
 123
 124     u32 i = pc_vector.size();
 125     for (u32* p = start; p < end; p++) *p = ++i;
 126     pc_vector.resize(i);
 127   }
 128
 129   void TracePcGuard(u32* guard, uptr pc) {
 130     u32 idx = *guard;
 131     if (!idx) return;
 132     // we start indices from 1.
 133     atomic_uintptr_t* pc_ptr =
 134         reinterpret_cast<atomic_uintptr_t*>(&pc_vector[idx - 1]);
 135     if (atomic_load(pc_ptr, memory_order_relaxed) == 0)
 136       atomic_store(pc_ptr, pc, memory_order_relaxed);
 137   }
 138
 139   void Reset() {
 140     internal_memset(&pc_vector[0], 0, sizeof(pc_vector[0]) * pc_vector.size());
 141   }
 142
 143   void Dump() {
 144     if (!initialized || !common_flags()->coverage) return;
 145     __sanitizer_dump_coverage(pc_vector.data(), pc_vector.size());
 146   }
 147
 148  private:
 149   bool initialized;
 150   InternalMmapVectorNoCtor<uptr> pc_vector;
 151 };
 152
 153 static TracePcGuardController pc_guard_controller;
 154
 155 }  // namespace
 156 }  // namespace __sancov
 157
 158 namespace __sanitizer {
 159 void InitializeCoverage(bool enabled, const char *dir) {
 160   static bool coverage_enabled = false;
 161   if (coverage_enabled)
 162     return;  // May happen if two sanitizer enable coverage in the same process.
 163   coverage_enabled = enabled;
 164   Atexit(__sanitizer_cov_dump);
 165   AddDieCallback(__sanitizer_cov_dump);
 166 }
 167 } // namespace __sanitizer
 168
 169 extern "C" {
 170 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_coverage(  // NOLINT
 171     const uptr* pcs, uptr len) {
 172   return __sancov::SanitizerDumpCoverage(pcs, len);
 173 }
 174
 175 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32* guard) {
 176   if (!*guard) return;
 177   __sancov::pc_guard_controller.TracePcGuard(guard, GET_CALLER_PC() - 1);
 178 }
 179
 180 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init,
 181                              u32* start, u32* end) {
 182   if (start == end || *start) return;
 183   __sancov::pc_guard_controller.InitTracePcGuard(start, end);
 184 }
 185
 186 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_dump_trace_pc_guard_coverage() {
 187   __sancov::pc_guard_controller.Dump();
 188 }
 189 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_dump() {
 190   __sanitizer_dump_trace_pc_guard_coverage();
 191 }
 192 SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_cov_reset() {
 193   __sancov::pc_guard_controller.Reset();
 194 }
 195 // Default empty implementations (weak). Users should redefine them.
 196 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp, void) {}
 197 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp1, void) {}
 198 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp2, void) {}
 199 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp4, void) {}
 200 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_cmp8, void) {}
 201 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp1, void) {}
 202 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp2, void) {}
 203 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp4, void) {}
 204 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp8, void) {}
 205 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_switch, void) {}
 206 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div4, void) {}
 207 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div8, void) {}
 208 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_gep, void) {}
 209 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
 210 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_8bit_counters_init, void) {}
 211 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, void) {}
 212 }  // extern "C"
 213 // Weak definition for code instrumented with -fsanitize-coverage=stack-depth
 214 // and later linked with code containing a strong definition.
 215 // E.g., -fsanitize=fuzzer-no-link
 216 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 217 SANITIZER_TLS_INITIAL_EXEC_ATTRIBUTE uptr __sancov_lowest_stack;
 218
 219 #endif  // !SANITIZER_FUCHSIA