[Lldb-commits] win32: Memory mapped have to be aligned on the right boundary

[Carlo Kok]

The current trunk implementation of win32 mapped files works fine if the 
start address is 0, but if the start address is not 0, the memory 
mapping fails. This is because mapviewoffile has to be aligned on the 
system's dwAllocationGranularity. This patch fixes that. (This is used 
when loading a Mach-O universal files, which have embedded files in them)

--
Carlo Kok
RemObjects Software
Index: C:/Projects/oxygene-nougat-llvm/lldb/source/Core/DataBufferMemoryMap.cpp
===================================================================
--- C:/Projects/oxygene-nougat-llvm/lldb/source/Core/DataBufferMemoryMap.cpp    
(revision 191382)
+++ C:/Projects/oxygene-nougat-llvm/lldb/source/Core/DataBufferMemoryMap.cpp    
(working copy)
@@ -147,8 +147,18 @@
     Clear();
     return 0;
 }
+
+
+#ifdef _WIN32
+static size_t win32memmapalignment = 0;
+void LoadWin32MemMapAlignment ()
+{
+  SYSTEM_INFO data;
+  GetSystemInfo(&data);
+  win32memmapalignment = data.dwAllocationGranularity;
+}
+#endif
 
-
 //----------------------------------------------------------------------
 // The file descriptor FD is assumed to already be opened as read only
 // and the STAT structure is assumed to a valid pointer and already
@@ -206,13 +216,23 @@
             HANDLE fileMapping = CreateFileMapping(handle, NULL, writeable ? 
PAGE_READWRITE : PAGE_READONLY, file_size_high, file_size_low, NULL);
             if (fileMapping != NULL)
             {
-                m_mmap_addr = (uint8_t*)MapViewOfFile(fileMapping, writeable ? 
FILE_MAP_ALL_ACCESS : FILE_MAP_READ, (DWORD)(offset >> 32), (DWORD)(offset), 
length);
-                if (m_mmap_addr != NULL)
-                {
-                    m_mmap_size = length;
-                    m_data = m_mmap_addr;
-                    m_size = length;
-                }
+                if (win32memmapalignment == 0) LoadWin32MemMapAlignment();
+                lldb::offset_t realoffset = offset;
+                lldb::offset_t delta = 0;
+                if (realoffset % win32memmapalignment != 0) {
+                  realoffset = realoffset / win32memmapalignment * 
win32memmapalignment;
+                  delta = offset - realoffset;
+                     }
+
+                LPVOID data = MapViewOfFile(fileMapping, writeable ? 
FILE_MAP_WRITE : FILE_MAP_READ, 0, realoffset, length + delta);
+                m_mmap_addr = (uint8_t *)data;
+                if (!data) {
+                  Error error; 
+                  error.SetErrorToErrno ();
+                } else {
+                  m_data = m_mmap_addr + delta;
+                  m_size = length;
+                }
                 CloseHandle(fileMapping);
             }
         }
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