[LLVMdev] variable size alloca

[Eli Friedman]

On Tue, Sep 16, 2008 at 6:23 PM, Ryan M. Lefever <lefever at crhc.uiuc.edu> wrote:
> To what do variable size LLVM alloca instructions get translated, when
> they are turned into machine code?  I compiled a piece of code to
> bitcode and disassembled it.  The disassembled code showed that there
> were alloca instructions with variable-sized parameters within the
> bitcode.  When I turned the bitcode into machine code, I performed an nm
> on the result but didn't see any symbols referring to alloca.  So, I'm
> guessing that they don't get translated to an alloca system call.  If
> that's the case, to what do they get translated?

It depends on your architecture/operating system, but it normally gets
transformed into arithmetic on the stack pointer.

-Eli