From eae79fdb34f8a223cb1b58de24de80771c14adb7 Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Fri, 11 Feb 2011 15:02:09 -0700
Subject: [PATCH] clean up MINIDUMP_EXCEPTION_INFORMATION mess in windows.cpp

The last two commits were meant to work around a supposed bug in
mingw-w64's dbghelp.h, but closer inspection reminded me that we're
not using dbghelp.h at all; legacy mingw doesn't have it, so we had to
declare the structures we needed ourselves based on the MSDN
documentation.  What that documentation doesn't mention is that
MINIDUMP_EXCEPTION_INFORMATION is subject to a special, packed layout,
which we must represent using the __packed__ attribute.
---
 src/windows.cpp | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/src/windows.cpp b/src/windows.cpp
index 21b9a0ed64..c4809c072c 100644
--- a/src/windows.cpp
+++ b/src/windows.cpp
@@ -833,7 +833,7 @@ class MySystem: public System {
   const char* crashDumpDirectory;
 };
 
-struct MINIDUMP_EXCEPTION_INFORMATION {
+struct __attribute__ ((__packed__)) MINIDUMP_EXCEPTION_INFORMATION {
   DWORD thread;
   LPEXCEPTION_POINTERS exception;
   BOOL exceptionInCurrentAddressSpace;
@@ -856,16 +856,6 @@ typedef BOOL (*MiniDumpWriteDumpType)
  const MINIDUMP_USER_STREAM_INFORMATION* userStream,
  const MINIDUMP_CALLBACK_INFORMATION* callback);
 
-// dbghelp.dll expects that MINIDUMP_EXCEPTION_INFORMATION has a
-// packed layout and will crash if it doesn't (at least on 64-bit
-// systems), but as of this writing mingw-w64's version is not
-// declared to be so.  Hence this workaround:
-struct __attribute__ ((__packed__)) My_MINIDUMP_EXCEPTION_INFORMATION {
-  DWORD ThreadId;
-  PEXCEPTION_POINTERS ExceptionPointers;
-  WINBOOL ClientPointers;
-};
-
 void
 dump(LPEXCEPTION_POINTERS e, const char* directory)
 {
@@ -887,22 +877,15 @@ dump(LPEXCEPTION_POINTERS e, const char* directory)
         (name, FILE_WRITE_DATA, 0, 0, CREATE_ALWAYS, 0, 0);
 
       if (file != INVALID_HANDLE_VALUE) {
-        My_MINIDUMP_EXCEPTION_INFORMATION exception
+        MINIDUMP_EXCEPTION_INFORMATION exception
            = { GetCurrentThreadId(), e, true };
- 
-        union {
-          MINIDUMP_EXCEPTION_INFORMATION* exceptionPointer;
-          My_MINIDUMP_EXCEPTION_INFORMATION* myExceptionPointer;
-        };
-
-        myExceptionPointer = &exception;
 
          MiniDumpWriteDump
            (GetCurrentProcess(),
             GetCurrentProcessId(),
             file,
             MiniDumpWithFullMemory,
-            exceptionPointer,
+            &exception,
             0,
             0);