On 04/25/16 13:49, Alexander Monakov wrote:
On Mon, 25 Apr 2016, Nathan Sidwell wrote:
acceptable?
No, that really doesn't sound viable. You'd need to somehow take into account
every instance where the compiler attempts to switch sections internally
(.text/.data/.bss, -ffunction-sections/-fdata-sections etc.).
Hm, -f{function/data}=sections would be the killer here.
Ugh. Checking DECL_INITIAL in nvptx_encode_section_info would be much
simpler (and that's how other backends perform a similar test).
If that's available, then great.
Note, rejecting zero-initializers is debatable:
C and C++ don't have a concept of uninitialized global-scope data; if
the initializer is missing, it's exactly as if it was 0. However, GCC has
-fcommon enabled by default (which, btw, shouldn't we change on NVPTX?), and
that makes a difference: 'int v = 0;' is a strong definition, while 'int v;'
becomes a common symbol, and ultimately a weak definition on NVPTX.
So if all-zeros initializers are rejected, to make a strong definition of a
shared variable one would have to write:
I think we should reject the cases where the backend gets to see an explicit
initializer.
fno-common would be a good default for PTX (I had thought it was already on?)
nathan
