Hello, As mentioned in a previous discussion at http://gcc.gnu.org/ml/gcc/2005-04/msg01416.html
we have troubles with the expand_main_function code to adjust the stack pointer to PREFERRED_STACK_BOUNDARY on entry points. It currently aligns the stack pointer by applying explicit operations on it and then resorts to allocate_dynamic_stack_space to "pick up the pieces", as the comment says: /* Forcibly align the stack. */ [...] /* Enlist allocate_dynamic_stack_space to pick up the pieces. */ We are using that code on an eabi ppc target to ensure PREFERRED_STACK_BOUNDARY is honored. The current code badly interacts with the ABI because the back-chain cannot be found at the address denoted by the stack pointer after the first step above if it actually affects the register. A possible way to address that is to have expand_main_function compute the distance between the current and aligned values of the stack pointer (without touching it), and resort to allocate_dynamic_stack_space to allocate exactly that amount. We have thought of slighlty updating the allocate_dynamic_stack_space interface and code for the sake of this specific interaction. I can provide more details as well as a tentative patch, and would be glad to hear opinions on the overall issue and approach first, so ... Thanks in advance for your help, Olivier
