[ASan/Win] Handle situations when the client app has used DbgHelp before

[kcc]

LGTM

[timurrrr]

r213151.

lib/sanitizer_common/sanitizer_symbolizer_win.cc

public:
   WinSymbolizer() : initialized_(false) {}
 
   uptr SymbolizePC(uptr addr, AddressInfo *frames, uptr max_frames) {
     if (max_frames == 0)
       return 0;
 
     BlockingMutexLock l(&dbghelp_mu_);
     if (!initialized_) {
-      SymSetOptions(SYMOPT_DEFERRED_LOADS |
-                    SYMOPT_UNDNAME |
-                    SYMOPT_LOAD_LINES);
-      CHECK(SymInitialize(GetCurrentProcess(), 0, TRUE));
-      // FIXME: We don't call SymCleanup() on exit yet - should we?
+      if (!TrySymInitialize()) {
+        // OK, maybe the client app has called SymInitialize already.
+        // That's a bit unfortunate for us as all the DbgHelp functions are
+        // single-threaded and we can't coordinate with the app.
+        // FIXME: Can we stop the other threads at this point?
+        // Anyways, we have to reconfigure stuff to make sure that SymInitialize
+        // has all the appropriate options set.
+        // Cross our fingers and reinitialize DbgHelp.
+        CHECK(SymCleanup(GetCurrentProcess()));
+        CHECK(TrySymInitialize());
+      }
       initialized_ = true;
     }
 
     // See http://msdn.microsoft.com/en-us/library/ms680578(VS.85).aspx
     char buffer[sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(CHAR)];
     PSYMBOL_INFO symbol = (PSYMBOL_INFO)buffer;
     symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
     symbol->MaxNameLen = MAX_SYM_NAME;
if (name[0] == '\01' &&
       return demangle_buffer;
     else
       return name;
   }
 
   // FIXME: Implement GetModuleNameAndOffsetForPC().
 
  private:
+  bool TrySymInitialize() {
+    SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_UNDNAME | SYMOPT_LOAD_LINES);
+    return SymInitialize(GetCurrentProcess(), 0, TRUE);
+    // FIXME: We don't call SymCleanup() on exit yet - should we?
+  }
+
   // All DbgHelp functions are single threaded, so we should use a mutex to
   // serialize accesses.
   BlockingMutex dbghelp_mu_;
   bool initialized_;
 };
 
 Symbolizer *Symbolizer::PlatformInit(const char *path_to_external) {
   static bool called_once = false;
   CHECK(!called_once && "Shouldn't create more than one symbolizer");
   called_once = true;
   return new(symbolizer_allocator_) WinSymbolizer();
 }
 
 }  // namespace __sanitizer
 
 #endif  // _WIN32

test/asan/TestCases/Windows/report_after_syminitialize.cc

+// RUN: %clangxx_asan -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+#include <windows.h>
+#include <dbghelp.h>
+
+int main() {
+  // Make sure the RTL recovers from "no options enabled" dbghelp setup.
+  SymSetOptions(0);
+
+  // Make sure the RTL recovers from "fInvadeProcess=FALSE".
+  if (!SymInitialize(GetCurrentProcess(), 0, FALSE))
+    return 42;
+
+  *(int*)0 = 42;
+  // CHECK: ERROR: AddressSanitizer: access-violation on unknown address
+  // CHECK-NEXT: {{#0 0x.* in main.*report_after_syminitialize.cc:}}[[@LINE-2]]
+  // CHECK: AddressSanitizer can not provide additional info.
+}