"John S. Yates, Jr." <jyates@xxxxxxxxxxx> writes: > > "Falk Hueffner" <falk.hueffner@xxxxxxxxxxxxxxxxxxxxxxxx> writes: > > > > It's an expected limitation. asm's are not supposed to > > change the control flow. The manual could probably more > > explicit about this... > > I find this assertion hard to believe. The gcc manual shows an > explicit example of using an asm() to make a call. If your > assertion is truly gcc's reasoned design intent then it implies that > any author of an asm() containing a call is responsible for ensuring > that the transitive closure of all code reachable from that call is > and remains free of exception possibilities for all time. Surely > such drastic consequences from a design choice would have merited a > cautionary comment of some sort... > > I therefore put it to you that this is not simply a deficiency in > gcc documentation but rather a legitimate bug. True, a fix might > require additional syntax... But as things stand asm() is a > festering gotcha. I basically agree. I suggest you file a bug report against the documentation for not documenting the status quo properly. Then you might also file a bug report asking for a mechanism to make this work reliably. > > Maybe you could try to generate the required .eh_frames manually, > > I think the Linux kernel does this somewhere. > > I am desperate and willing to try anything. Searching the web > based-on your suggestion I found the following article: > > http://www.tldp.org/LDP/khg/HyperNews/get/devices/exceptions.html > > I believe I could indeed do something similar if I knew enough > about the contents of .eh_frames. So far though I have had no > luck looking for documentation. Any suggestions? As a bit of voodoo, try not to use -fomit-frame-pointer in case you currently do, and try adding memory to the clobber list (you should probably do that anyway, since the functions you call might change memory). This article gives some overview of the EH mechanism: http://gcc.gnu.org/ml/gcc/2002-07/msg00391.html Other than that, I've no idea either... -- Falk
