r256412 - in /trunk/gcc/go/gofrontend: MERGE ex...

[ian@gcc.gnu.org]

Author: ian
Date: Tue Jan  9 23:56:54 2018
New Revision: 256412

URL: https://gcc.gnu.org/viewcvs?rev=256412&root=gcc&view=rev
Log:
    compiler: use temporary variable for stack allocation
    
    Currently, allocation expression that can be allocated on stack
    is implemented with __builtin_alloca, which turns into
    __morestack_allocate_stack_space, which may call C malloc. This
    may be slow. Also if this happens during certain runtime
    functions (e.g. write barrier), bad things might happen (when
    the escape analysis is enabled for the runtime). Make a temporary
    variable on stack for the allocation instead.
    
    Also remove the write barrier in the assignment in building heap
    expression when it is stack allocated.
    
    Reviewed-on: https://go-review.googlesource.com/86242

Modified:
    trunk/gcc/go/gofrontend/MERGE
    trunk/gcc/go/gofrontend/expressions.cc