[sanitizer] Track which modules are instrumented in LoadedModule objects

[kubamracek]

Summary

This patch adds tracking which modules are instrumented and which are not. On macOS, instrumented modules link against the ASan/TSan/... dylib, so we can just check if such a load command exists or not.

This is needed to implement a feature that needs to know if an interceptor is called from instrumented code or not (then it's likely a system library). The patch for that will follow.

[kubamracek]

https://reviews.llvm.org/D28264 ("Implement a 'ignore_noninstrumented_modules' flag to better suppress false positive races") builds on top of this patch.

lib/sanitizer_common/sanitizer_common.h

 
 const uptr kModuleUUIDSize = 16;
 
 // Represents a binary loaded into virtual memory (e.g. this can be an
 // executable or a shared object).
 class LoadedModule {
  public:
   LoadedModule()
-      : full_name_(nullptr), base_address_(0), arch_(kModuleArchUnknown) {
+      : full_name_(nullptr),
+        base_address_(0),
+        arch_(kModuleArchUnknown),
+        instrumented_(false) {
     internal_memset(uuid_, 0, kModuleUUIDSize);
     ranges_.clear();
   }
   void set(const char *module_name, uptr base_address);
   void set(const char *module_name, uptr base_address, ModuleArch arch,
-           u8 uuid[kModuleUUIDSize]);
+           u8 uuid[kModuleUUIDSize], bool instrumented);
   void clear();
   void addAddressRange(uptr beg, uptr end, bool executable);
   bool containsAddress(uptr address) const;
 
   const char *full_name() const { return full_name_; }
   uptr base_address() const { return base_address_; }
   ModuleArch arch() const { return arch_; }
   const u8 *uuid() const { return uuid_; }
+  bool instrumented() const { return instrumented_; }
 
   struct AddressRange {
     AddressRange *next;
     uptr beg;
     uptr end;
     bool executable;
 
     AddressRange(uptr beg, uptr end, bool executable)
         : next(nullptr), beg(beg), end(end), executable(executable) {}
   };
 
   const IntrusiveList<AddressRange> &ranges() const { return ranges_; }
 
  private:
   char *full_name_;  // Owned.
   uptr base_address_;
   ModuleArch arch_;
   u8 uuid_[kModuleUUIDSize];
+  bool instrumented_;
   IntrusiveList<AddressRange> ranges_;
 };
 
 // List of LoadedModules. OS-dependent implementation is responsible for
 // filling this information.
 class ListOfModules {
  public:
   ListOfModules() : modules_(kInitialCapacity) {}

lib/sanitizer_common/sanitizer_common.cc

 
 void LoadedModule::set(const char *module_name, uptr base_address) {
   clear();
   full_name_ = internal_strdup(module_name);
   base_address_ = base_address;
 }
 
 void LoadedModule::set(const char *module_name, uptr base_address,
-                       ModuleArch arch, u8 uuid[kModuleUUIDSize]) {
+                       ModuleArch arch, u8 uuid[kModuleUUIDSize],
+                       bool instrumented) {
   set(module_name, base_address);
   arch_ = arch;
   internal_memcpy(uuid_, uuid, sizeof(uuid_));
+  instrumented_ = instrumented;
 }
 
 void LoadedModule::clear() {
   InternalFree(full_name_);
   full_name_ = nullptr;
   arch_ = kModuleArchUnknown;
   internal_memset(uuid_, 0, kModuleUUIDSize);
+  instrumented_ = false;
   while (!ranges_.empty()) {
     AddressRange *r = ranges_.front();
     ranges_.pop_front();
     InternalFree(r);
   }
 }
 
 void LoadedModule::addAddressRange(uptr beg, uptr end, bool executable) {

lib/sanitizer_common/sanitizer_procmaps.h

bool NextSegmentLoad(uptr *start, uptr *end, uptr *offset, char filename[],
                        uptr *protection);
   int current_image_;
   u32 current_magic_;
   u32 current_filetype_;
   ModuleArch current_arch_;
   u8 current_uuid_[kModuleUUIDSize];
   int current_load_cmd_count_;
   char *current_load_cmd_addr_;
+  bool current_instrumented_;
 # endif
 };
 
 typedef void (*fill_profile_f)(uptr start, uptr rss, bool file,
                                /*out*/uptr *stats, uptr stats_size);
 
 // Parse the contents of /proc/self/smaps and generate a memory profile.
 // |cb| is a tool-specific callback that fills the |stats| array containing

lib/sanitizer_common/sanitizer_procmaps_mac.cc

switch (cputype) {
     case CPU_TYPE_ARM64:
       return kModuleArchARM64;
     default:
       CHECK(0 && "Invalid CPU type");
       return kModuleArchUnknown;
   }
 }
 
+static const load_command *NextCommand(const load_command *lc) {
+  return (const load_command *)((char *)lc + lc->cmdsize);
+}
+
 static void FindUUID(const load_command *first_lc, u8 *uuid_output) {
-  const load_command *current_lc = first_lc;
-  while (1) {
-    if (current_lc->cmd == 0) return;
-    if (current_lc->cmd == LC_UUID) {
-      const uuid_command *uuid_lc = (const uuid_command *)current_lc;
-      const uint8_t *uuid = &uuid_lc->uuid[0];
-      internal_memcpy(uuid_output, uuid, kModuleUUIDSize);
-      return;
-    }
+  for (const load_command *lc = first_lc; lc->cmd != 0; lc = NextCommand(lc)) {
+    if (lc->cmd != LC_UUID) continue;
+
+    const uuid_command *uuid_lc = (const uuid_command *)lc;
+}
 
-    current_lc =
-        (const load_command *)(((char *)current_lc) + current_lc->cmdsize);
+static bool IsModuleInstrumented(const load_command *first_lc) {
+  for (const load_command *lc = first_lc; lc->cmd != 0; lc = NextCommand(lc)) {
+    if (lc->cmd != LC_LOAD_DYLIB) continue;
+
+    const dylib_command *dylib_lc = (const dylib_command *)lc;
+    uint32_t dylib_name_offset = dylib_lc->dylib.name.offset;
+    const char *dylib_name = ((const char *)dylib_lc) + dylib_name_offset;
+    dylib_name = StripModuleName(dylib_name);
+    if (dylib_name != 0 && (internal_strstr(dylib_name, "libclang_rt."))) {
+      return true;
     }
   }
+  return false;
+}
 
 bool MemoryMappingLayout::Next(uptr *start, uptr *end, uptr *offset,
                                char filename[], uptr filename_size,
                                uptr *protection, ModuleArch *arch, u8 *uuid) {
   for (; current_image_ >= 0; current_image_--) {
     const mach_header* hdr = _dyld_get_image_header(current_image_);
     if (!hdr) continue;
     if (current_load_cmd_count_ < 0) {
#endif
         case MH_MAGIC: {
           current_load_cmd_addr_ = (char*)hdr + sizeof(mach_header);
           break;
         }
         default: {
           continue;
         }
       }
-    }
-
       FindUUID((const load_command *)current_load_cmd_addr_, &current_uuid_[0]);
+      current_instrumented_ =
+          IsModuleInstrumented((const load_command *)current_load_cmd_addr_);
+    }
 
     for (; current_load_cmd_count_ >= 0; current_load_cmd_count_--) {
       switch (current_magic_) {
         // current_magic_ may be only one of MH_MAGIC, MH_MAGIC_64.
 #ifdef MH_MAGIC_64
         case MH_MAGIC_64: {
           if (NextSegmentLoad<LC_SEGMENT_64, struct segment_command_64>(
                   start, end, offset, filename, filename_size, arch, uuid,
if (cur_name[0] == '\0')
       continue;
     LoadedModule *cur_module = nullptr;
     if (!modules->empty() &&
         0 == internal_strcmp(cur_name, modules->back().full_name())) {
       cur_module = &modules->back();
     } else {
       modules->push_back(LoadedModule());
       cur_module = &modules->back();
-      cur_module->set(cur_name, cur_beg, cur_arch, cur_uuid);
+      cur_module->set(cur_name, cur_beg, cur_arch, cur_uuid,
+                      current_instrumented_);
     }
     cur_module->addAddressRange(cur_beg, cur_end, prot & kProtectionExecute);
   }
 }
 
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_MAC