On 08/12/2012 12:34 AM, David Nadlinger wrote:
On Saturday, 11 August 2012 at 22:17:44 UTC, Timon Gehr wrote:
Will generated code differ?
Only the mangled symbol name will differ. (unlike when scope is used on
delegate parameters, in this case it prevents closure allocation at
the call site.)
The code for callee stays the same, yes, but the code for the caller
might change as the optimizer is free to take advantage of the fact that
any reference in the parameters will not be escaped by the function. For
example, LDC will stack-allocate dynamic arrays and objects if they are
local to the function. [1]
David
[1] The fine print: We currently don't take advantage of "scope"
parameters for this yet, though (it seems too dangerous with the related
analysis not being implemented in the frontend), and for a completely
unrelated reason, the code which performs the mentioned optimization is
disabled in current master (but will be re-enabled in the near future,
before the September release).
Is there an upper bound on the amount of allocated memory? Implicit
stack-allocation of arbitrarily-sized dynamic arrays seems dangerous.
