Index: gcc/config/i386/host-mingw32.c
===================================================================
--- gcc/config/i386/host-mingw32.c	(revision 129490)
+++ gcc/config/i386/host-mingw32.c	(working copy)
@@ -28,6 +28,8 @@
 
 
 #define WIN32_LEAN_AND_MEAN  /* Not so important if we have windows.h.gch.  */
+#include <tchar.h>
+#include <stdlib.h>
 #include <windows.h>
 
 static void * mingw32_gt_pch_get_address (size_t, int);
@@ -47,7 +49,7 @@
 static const size_t pch_VA_max_size  = 128 * 1024 * 1024;
 
 /* Granularity for reserving address space.  */
-static const size_t va_granularity = 0x10000;
+static size_t va_granularity = 0x10000;
 
 /* Print out the GetLastError() translation.  */ 
 static inline void
@@ -70,7 +72,9 @@
 /* Granularity for reserving address space.  */
 static size_t mingw32_gt_pch_alloc_granularity (void)
 {
-  return va_granularity;
+  SYSTEM_INFO SysInfo;
+  GetSystemInfo(&SysInfo);
+  return (va_granularity = (size_t)SysInfo.dwAllocationGranularity);
 }
 
 /* Identify an address that's likely to be free in a subsequent invocation
@@ -116,6 +120,9 @@
 {
   void * mmap_addr;
   static HANDLE mmap_handle;
+  TCHAR szMappingName[26];
+  OSVERSIONINFO version_info;
+  int i = 0;
 
   if (size == 0)
     return 0;
@@ -125,16 +132,49 @@
   if ((offset & (va_granularity - 1)) != 0 || size > pch_VA_max_size)
     return -1;
 
-  mmap_handle = CreateFileMapping ((HANDLE) _get_osfhandle (fd),
-				   NULL, PAGE_WRITECOPY | SEC_COMMIT,
-				   0, 0,  NULL);
+  /* Determine the version of Windows we are running on.  */
+  version_info.dwOSVersionInfoSize = sizeof (version_info);
+  GetVersionEx (&version_info);
+
+  srand(1);
+  while (1)
+    {
+      /* Generate a unique mapping name. This is neccessary to avoid
+         needing the SeCreateGlobalPrivilege privilege in certain cases.
+         However, the documentation for CreateFileMapping says that on NT4
+         and earlier, backslashes are invalid in object name.  So, we need
+         to check if we are on Windows2000 or higher.  */
+      _stprintf(szMappingName, _T("Local\\MinGWGCCPCH%08X"), rand());
+      mmap_handle = CreateFileMapping ((HANDLE) _get_osfhandle (fd),
+					   NULL, PAGE_WRITECOPY | SEC_COMMIT,
+					   0, 0,  (version_info.dwMajorVersion >
+					   4 ? szMappingName : NULL));
+      if (mmap_handle != NULL && GetLastError() == ERROR_ALREADY_EXISTS)
+          CloseHandle(mmap_handle);
+      else
+          break;
+    }
+
   if (mmap_handle == NULL)
     {
       w32_error (__FUNCTION__,  __FILE__, __LINE__, "CreateFileMapping");
       return -1; 
     }
-  mmap_addr = MapViewOfFileEx (mmap_handle, FILE_MAP_COPY, 0, offset,
-			       size, addr);
+  /* wait/retry a couple of times if needed.
+     Fixes a race when running multiple gcc's (-j) */
+  for(i = 0; i < 5; i++)
+    {
+      mmap_addr = MapViewOfFileEx (mmap_handle, FILE_MAP_COPY, 0, offset,
+			         size, addr);
+	  if (mmap_addr != addr)
+	    {
+	      Sleep(500);
+	    }
+	  else
+	    {
+	      break;
+	    }
+	}
   if (mmap_addr != addr)
     {
       w32_error (__FUNCTION__, __FILE__, __LINE__, "MapViewOfFileEx");