[tsan] Add global symbolication support into DlAddrSymbolizer

[kubamracek]

Summary

DlAddrSymbolizer is used on OS X when we're running inside a sandbox that prevents us from spawning an external symbolizer. This patch adds support for symbolication of globals (implements SymbolizeData) for DlAddrSymbolizer.

[glider]

LGTM

test/tsan/Darwin/symbolizer-dladdr.cc

2

Do we also want an ASan test for this functionality?

21

dvyukov: do we want to rename barrier_wait() to e.g. invisible_barrier_wait() or smth. else that indicates TSan doesn't know about this barrier?

[kubamracek]

test/tsan/Darwin/symbolizer-dladdr.cc

2

We have some dladdr tests in dladdr-demangling.cc, sandbox-symbolizer.cc and suppressions-sandbox.cc. Or did you mean to specifically add a test for symbolication of globals?

lib/sanitizer_common/sanitizer_symbolizer_mac.cc

bool DlAddrSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
   Dl_info info;
   int result = dladdr((const void *)addr, &info);
   if (!result) return false;
   const char *demangled = DemangleCXXABI(info.dli_sname);
   stack->info.function = internal_strdup(demangled);
   return true;
 }
 
-bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
-  return false;
+bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
+  Dl_info info;
+  int result = dladdr((const void *)addr, &info);
+  if (!result) return false;
+  const char *demangled = DemangleCXXABI(info.dli_sname);
+  datainfo->name = internal_strdup(demangled);
+  datainfo->start = (uptr)info.dli_saddr;
+  return true;
 }
 
 class AtosSymbolizerProcess : public SymbolizerProcess {
  public:
   explicit AtosSymbolizerProcess(const char *path, pid_t parent_pid)
       : SymbolizerProcess(path, /*use_forkpty*/ true) {
     // Put the string command line argument in the object so that it outlives
     // the call to GetArgV.

test/tsan/Darwin/symbolizer-dladdr.cc

+// RUN: %clangxx_tsan %s -o %t
+// RUN: TSAN_OPTIONS=$TSAN_OPTIONS:verbosity=2:external_symbolizer_path= %deflake %run %t | FileCheck %s
+#include "../test.h"
+
+int GlobalData[10];
+
+void *Thread(void *a) {
+  barrier_wait(&barrier);
+  GlobalData[2] = 42;
+  return 0;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  fprintf(stderr, "addr=");
+  print_address(GlobalData);
+  fprintf(stderr, "\n");
+  pthread_t t;
+  pthread_create(&t, 0, Thread, 0);
+  GlobalData[2] = 43;
+  barrier_wait(&barrier);
+  pthread_join(t, 0);
+}
+
+// CHECK: External symbolizer is explicitly disabled.
+// CHECK: Using dladdr symbolizer.
+// CHECK: addr=[[ADDR:0x[0-9,a-f]+]]
+// CHECK: WARNING: ThreadSanitizer: data race
+// CHECK: Location is global 'GlobalData' at [[ADDR]] ({{.*}}+0x{{[0-9,a-f]+}})