[compiler-rt] r333595 - [asan] Remove unneeded VirtualQuery from exception handler

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Wed May 30 14:21:18 2018
New Revision: 333595

URL: http://llvm.org/viewvc/llvm-project?rev=333595&view=rev
Log:
[asan] Remove unneeded VirtualQuery from exception handler

We don't use the result of the query, and all tests pass if I remove it.
During startup, ASan spends a fair amount of time in this handler, and
the query is much more expensive than the call to commit the memory.

Modified:
    compiler-rt/trunk/lib/asan/asan_win.cc

Modified: compiler-rt/trunk/lib/asan/asan_win.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_win.cc?rev=333595&r1=333594&r2=333595&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_win.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_win.cc Wed May 30 14:21:18 2018
@@ -265,11 +265,6 @@ ShadowExceptionHandler(PEXCEPTION_POINTE
   // Determine the address of the page that is being accessed.
   uptr page = RoundDownTo(addr, page_size);
 
-  // Query the existing page.
-  MEMORY_BASIC_INFORMATION mem_info = {};
-  if (::VirtualQuery((LPVOID)page, &mem_info, sizeof(mem_info)) == 0)
-    return EXCEPTION_CONTINUE_SEARCH;
-
   // Commit the page.
   uptr result =
       (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);