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