Hi, I am working on mobile CE devices and I use cegcc (when it's possible) to developp software. There is one feature I miss with gcc called SEH exceptions and since I have seen a recent post about SEH x64 I think it's the right moment to talk about it.
First SEH exceptions exists in two kinds : 1) SEH called "frame-based" and I think that historically it was the first kind of implementation. This is described here http://www.microsoft.com/msj/0197/exception/exception.aspx. I think this mechanism is used only on x86(32 bits) because it relies on a specific register FS:[0] and is based on a linked list. 2) SEH called "table-based" used on all other platforms(x64, ARM, MIPS, ...) than x86. In this case exception info are stored into a .pdata section (at least on ARM not sure about x64) The Function Table (interpreted .pdata section contents) vma: Begin Prolog Function Flags Exception EH Address Length Length 32b exc Handler Data 00014000 00011008 00000004 00000015 1 1 00011090 000120dc 00014008 0001105c 00000001 00000009 1 0 e24bd010 e89da810 00014010 000110a0 00000002 00000093 1 0 e12fff1c 00013004 00014018 000112f4 00000004 00000030 1 1 00011090 000120f0 00014020 000113b4 00000001 0000000b 1 0 e91b6810 e12fff1e 00014028 000113e0 00000001 0000001b 1 0 0001305c 00013058 00014030 0001144c 00000001 00000041 1 0 00013040 0001303c 00014038 00011550 00000001 00000006 1 0 00013070 00013074 00014040 0001157c 00000002 0000000e 1 0 01b0c820 012fff1e 00014048 000115c0 00000001 00000014 1 0 00013054 0000b064 typedef struct _SCOPE_TABLE { ULONG Count; struct { ULONG BeginAddress; ULONG EndAddress; ULONG HandlerAddress; ULONG JumpTarget; } ScopeRecord[1]; } SCOPE_TABLE, *PSCOPE_TABLE; SEH and gcc seems to be a long story because someone called Casper Hornstrup already had implemented frame-based SEH in 2003 for gcc 3.2 but his patch was never accepted for some bad reasons(it's a MS thing, Borland patents, ...). So I have proposed an internship to one student and he will try to implement table-based SEH exceptions into cegcc. He will work on it for six months, three days a week so I hope he will find some help on this ML. Normally this work will also benefit to x64 because the mechanism is almost the same. If you have suggestions/remarks/advice or if you want to participate please let us know. Some resources : [Frame Based SEH] http://www.microsoft.com/msj/0197/exception/exception.aspx [Table Based SEH on X64 - available only through Google cache] http://209.85.129.132/search?q=cache:ycabCQnoeFoJ:www.osronline.com/article.cfm%3Farticle%3D469+SEh+x64&hl=fr&ct=clnk&cd=1&gl=fr [Table Based SEH on ARM] http://code-factor.blogspot.com/2007/04/windows-ce-seh-for-arm-with-gcc.html [Misc] http://code-factor.blogspot.com/2007/09/windows-seh-revisited.html http://blogs.msdn.com/jaredpar/archive/2008/01/11/mixing-seh-and-c-exceptions.aspx http://cygwin.com/ml/cygwin/2002-08/msg01598.html Vincent Richomme http://www.smartmobili.com
