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<div class="moz-cite-prefix">On 11/06/2013 10:55 PM, Paul Berry
wrote:<br>
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<div dir="ltr">On 5 November 2013 23:45, Tapani Pälli <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:tapani.palli@intel.com" target="_blank">tapani.palli@intel.com</a>></span>
wrote:<br>
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<div>On 11/05/2013 07:36 PM, Paul Berry wrote:<br>
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<div>On 1 November 2013 02:16, Tapani Pälli <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:tapani.palli@intel.com"
target="_blank">tapani.palli@intel.com</a>></span>
wrote:<br>
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style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"> +<br>
+/**<br>
+ * Function to create an unique string for
a ir_variable. This is<br>
+ * used by variable dereferences to
indicate the exact ir_variable<br>
+ * when deserialization happens.<br>
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<div>I still don't understand why we don't
just use the pointer for this purpose. It's
unique, and it takes up much less storage
than <name>_<decimal address>.<br>
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We need to construct a unique name to refer to when
reading so this is constructed here already. It could be
also just a counter like is used somewhere else (to have
assignment_tmp@1, assignment_tmp@2) but I wanted to keep
this code minimal as it's just unique naming.</div>
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<div>I'm sorry, there's still something I'm not
understanding. Before serialization, the names are not
unique. So I don't see why we need to create unique names
when reading. The goal should be to reproduce the IR data
structure that was saved as closely as possible.<br>
<br>
It seems like storing the address of the ir_variable (or
some other suitably determined unique numeric id) should
be sufficient for this. When we serialize the
ir_variable, we write out its unique numeric id. When we
serialize an ir_dereference_variable, we write out the
unique numeric id of the ir_variable it refers to. When
deserializing an ir_variable, we store the mapping from
its unique numeric id to its new address in memory in a
hash table. When deserializing an
ir_dereference_variable, we look up the unique numeric id
to find the address of the ir_variable that's already been
deserialized.<br>
<br>
It doesn't seem to me that uniqueness of names is
necessary anywhere in that process. What am I missing?<br>
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I think we are somewhat on the same page but the method you describe
here is another way to solve the same problem. Problem is to get
references to variables pointing to the exact correct variable. This
cannot be detected by variable name, which I wanted to use for it to
be very clear which variable we are referring to and I did not see
any harm in using such 'unique name', ir_print_visitor does similar
renaming in its output. I can change to use your method if renaming
is no good (haven't seen any issues with this though), I guess using
the hash should not affect the parsing performance, correct variable
is anyway searched from a list when creating a reference.<br>
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style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"> +<br>
+ for (unsigned i = 0; i <
ir->num_state_slots; i++) {<br>
+
blob.write_int32(&ir->state_slots[i].swizzle);<br>
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<div>Swizzles are unsigned 8-bit values. This
should be write_uint8.<br>
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OK, maybe the struct could also be changed to have only
8 bits instead of a int then.</div>
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<div>I could get behind that change.<br>
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<div class="gmail_quote">+ CACHE_DEBUG("write
%d prototypes\n", total);<br>
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style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"> +<br>
+ foreach_list_const(node, shader->ir)
{<br>
+ ir_instruction *const inst =
(ir_instruction *) node;<br>
+ if (inst->as_variable())<br>
+ if (save(inst))<br>
+ goto write_errors;<br>
+ }<br>
+<br>
+ foreach_list_const(node, shader->ir)
{<br>
+ ir_instruction *const inst =
(ir_instruction *) node;<br>
+ if (inst->as_function())<br>
+ if (save(inst))<br>
+ goto write_errors;<br>
+ }<br>
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<div>Why is it necessary to save the variables
and instructions first?<br>
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This is because during parsing we might encounter a call
to a function that does not exist yet, same goes for
variable references. Another way would be to modify the
reading side so that it makes 2 passes over the data but
I took this way as originally reader did not use mmap so
it was just simpler.<br>
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<div>Ok, I think you are correct about the functions. But I
believe for variables, the ir_variable always appears in
the IR before any references to it. Can someone confirm
this? (Ken or Ian perhaps?)<br>
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This would be good to confirm. I'm pretty sure I did this to tackle
a problem during parsing but I can't recall now .. I will check
this.<br>
<br>
// Tapani<br>
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