HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu (Christoph van Wuellen) (12/29/90)
When tracking down a problem with my new 386 compiler, I discovered that
Sun C compilers generate special code when leaving a function which
called alloca.
The problem occurs when registers used by register variables have to be
restored. Since the stack pointer is much lower now, they cannot be
retrieved using popl %edi (say), but by using movl -xxxx(%ebp),%edi.
Since this is generally inefficient and I do not like to generate code
which is dependent on a function that has been called (note that it is nothing
like __builtin_alloca !), does anybody have a 386 alloca source?
Stack frame:
arguments
return address
old stackpointer <--- ebp
locals
saved registers
<--- esp