[libunwind] [Windows] Add a log message if EnumProcessModules fails

Differential Revision: https://reviews.llvm.org/D69504

diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp
index 908c898..db67df4 100644 (file)
--- a/libunwind/src/AddressSpace.hpp
+++ b/libunwind/src/AddressSpace.hpp
@@ -433,8 +433,12 @@ inline bool LocalAddressSpace::findUnwindSections(pint_t targetAddr,
   HANDLE process = GetCurrentProcess();
   DWORD needed;
 
-  if (!EnumProcessModules(process, mods, sizeof(mods), &needed))
+  if (!EnumProcessModules(process, mods, sizeof(mods), &needed)) {
+    DWORD err = GetLastError();
+    _LIBUNWIND_TRACE_UNWINDING("findUnwindSections: EnumProcessModules failed, "
+                               "returned error %d", (int)err);
     return false;
+  }
 
   for (unsigned i = 0; i < (needed / sizeof(HMODULE)); i++) {
     PIMAGE_DOS_HEADER pidh = (PIMAGE_DOS_HEADER)mods[i];