Implement global pointer scanning for darwin leak sanitizer

[fjricci]

Thanks for all the reviews - there are roughly 15 patches left to go in my implementation, and then things should quiet down greatly.

[fjricci]

Refactor to eliminate duplicated code between darwin and linux

Didn't originally think to do this.

[kubamracek]

lib/lsan/lsan_common_mac.cc

108–109 ↗

(On Diff #95177)

Is this clang-format'd?

[fjricci]

lib/lsan/lsan_common_mac.cc

108–109 ↗

(On Diff #95177)

I'm not sure - I'll re-run before I merge.

compiler-rt/trunk/lib/lsan/lsan_common.h

 void ProcessGlobalRegions(Frontier *frontier);
 void ProcessPlatformSpecificAllocations(Frontier *frontier);
 // Run stoptheworld while holding any platform-specific locks.
 void DoStopTheWorld(StopTheWorldCallback callback, void* argument);
 
 void ScanRangeForPointers(uptr begin, uptr end,
                           Frontier *frontier,
                           const char *region_type, ChunkTag tag);
+void ScanGlobalRange(uptr begin, uptr end, Frontier *frontier);
 
 enum IgnoreObjectResult {
   kIgnoreObjectSuccess,
   kIgnoreObjectAlreadyIgnored,
   kIgnoreObjectInvalid
 };
 
 // Functions called from the parent tool.

compiler-rt/trunk/lib/lsan/lsan_common.cc

for (; pp + sizeof(void *) <= end; pp += alignment) {  // NOLINT
     m.set_tag(tag);
     LOG_POINTERS("%p: found %p pointing into chunk %p-%p of size %zu.\n", pp, p,
                  chunk, chunk + m.requested_size(), m.requested_size());
     if (frontier)
       frontier->push_back(chunk);
   }
 }
 
+// Scans a global range for pointers
+void ScanGlobalRange(uptr begin, uptr end, Frontier *frontier) {
+  uptr allocator_begin = 0, allocator_end = 0;
+  GetAllocatorGlobalRange(&allocator_begin, &allocator_end);
+  if (begin <= allocator_begin && allocator_begin < end) {
+    CHECK_LE(allocator_begin, allocator_end);
+    CHECK_LE(allocator_end, end);
+    if (begin < allocator_begin)
+      ScanRangeForPointers(begin, allocator_begin, frontier, "GLOBAL",
+                           kReachable);
+    if (allocator_end < end)
+      ScanRangeForPointers(allocator_end, end, frontier, "GLOBAL", kReachable);
+  } else {
+    ScanRangeForPointers(begin, end, frontier, "GLOBAL", kReachable);
+  }
+}
+
 void ForEachExtraStackRangeCb(uptr begin, uptr end, void* arg) {
   Frontier *frontier = reinterpret_cast<Frontier *>(arg);
   ScanRangeForPointers(begin, end, frontier, "FAKE STACK", kReachable);
 }
 
 // Scans thread data (stacks and TLS) for heap pointers.
 static void ProcessThreads(SuspendedThreadsList const &suspended_threads,
                            Frontier *frontier) {

compiler-rt/trunk/lib/lsan/lsan_common_linux.cc

for (uptr j = 0; j < info->dlpi_phnum; j++) {
     const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]);
     // We're looking for .data and .bss sections, which reside in writeable,
     // loadable segments.
     if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) ||
         (phdr->p_memsz == 0))
       continue;
     uptr begin = info->dlpi_addr + phdr->p_vaddr;
     uptr end = begin + phdr->p_memsz;
-    uptr allocator_begin = 0, allocator_end = 0;
-    GetAllocatorGlobalRange(&allocator_begin, &allocator_end);
-    if (begin <= allocator_begin && allocator_begin < end) {
-      CHECK_LE(allocator_begin, allocator_end);
-      CHECK_LE(allocator_end, end);
-      if (begin < allocator_begin)
-        ScanRangeForPointers(begin, allocator_begin, frontier, "GLOBAL",
-                             kReachable);
-      if (allocator_end < end)
-        ScanRangeForPointers(allocator_end, end, frontier, "GLOBAL",
-                             kReachable);
-    } else {
-      ScanRangeForPointers(begin, end, frontier, "GLOBAL", kReachable);
-    }
+    ScanGlobalRange(begin, end, frontier);
   }
   return 0;
 }
 
 // Scans global variables for heap pointers.
 void ProcessGlobalRegions(Frontier *frontier) {
   if (!flags()->use_globals) return;
   dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);

compiler-rt/trunk/lib/lsan/lsan_common_mac.cc

 AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }
 
 // Required on Linux for initialization of TLS behavior, but should not be
 // required on Darwin.
 void InitializePlatformSpecificModules() {}
 
 // Scans global variables for heap pointers.
 void ProcessGlobalRegions(Frontier *frontier) {
-  CHECK(0 && "unimplemented");
+  MemoryMappingLayout memory_mapping(false);
+  InternalMmapVector<LoadedModule> modules(/*initial_capacity*/ 128);
+  memory_mapping.DumpListOfModules(&modules);
+  for (uptr i = 0; i < modules.size(); ++i) {
+    // Even when global scanning is disabled, we still need to scan
+    // system libraries for stashed pointers
+    if (!flags()->use_globals && modules[i].instrumented()) continue;
+
+    for (const __sanitizer::LoadedModule::AddressRange &range :
+         modules[i].ranges()) {
+      if (range.executable) continue;
+
+      ScanGlobalRange(range.beg, range.end, frontier);
+    }
+  }
 }
 
 void ProcessPlatformSpecificAllocations(Frontier *frontier) {
   CHECK(0 && "unimplemented");
 }
 
 void DoStopTheWorld(StopTheWorldCallback callback, void *argument) {
   CHECK(0 && "unimplemented");
 }
 
 } // namespace __lsan
 
 #endif // CAN_SANITIZE_LEAKS && SANITIZER_MAC