bearophile wrote:
Frits van Bommel:
LDC actually still does a dynamic allocation there because it doesn't eliminate
dynamic allocations in loops.
I have compiled the loop in foo() with LDC:
[snip]
scope auto item = new AllocationItem(i);
[snip]
The asm of the core of the loop:
.LBB2_2:
movl $_D11gc_test2b_d14AllocationItem6__vtblZ, 8(%esp)
movl $0, 12(%esp)
movl %edi, 16(%esp)
movl %ebx, (%esp)
call _d_callfinalizer
incl %edi
cmpl %esi, %edi
jne .LBB2_2
I can see a call to finalizer, but not the allocation?
Sorry, I thought we were talking about the code without 'scope'. Of course the
class is indeed stack-allocated if you use scope.
(The following:
This is unfortunate, but I haven't yet had the time to figure out how to get the
optimization passes to prove the allocation can't be live when reached again.
(If multiple instances of memory allocated at the same allocation site may be
reachable at the same time, it's not safe to use a stack allocation instead of a
heap allocation)
only applies when 'scope' was not used, and the compiler therefore initially
heap-allocated it)
The new JavaVM with the option I have shown is clearly able to do such things.
Can't you take a look at the source code of the JavaVM? :-)
There's a huge amount of NIH in the open source :-)
I suspect the Java VM uses a different internal representation of the code than
LLVM does...
