On 01/13/2014 09:49 AM, Ian Romanick wrote:
> On 01/11/2014 02:37 AM, Kenneth Graunke wrote:
>> These can't use foreach_list since they want to skip over the first few
>> list elements. Just doing the ad-hoc list walking isn't too bad.
>>
>> Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
>> ---
>> src/glsl/ir_reader.cpp | 18 ++++++++++--------
>> 1 file changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/src/glsl/ir_reader.cpp b/src/glsl/ir_reader.cpp
>> index f5185d2..28923f3 100644
>> --- a/src/glsl/ir_reader.cpp
>> +++ b/src/glsl/ir_reader.cpp
>> @@ -205,11 +205,12 @@ ir_reader::read_function(s_expression *expr, bool
>> skip_body)
>> assert(added);
>> }
>>
>> - exec_list_iterator it = ((s_list *) expr)->subexpressions.iterator();
>> - it.next(); // skip "function" tag
>> - it.next(); // skip function name
>> - for (/* nothing */; it.has_next(); it.next()) {
>> - s_expression *s_sig = (s_expression *) it.get();
>> + /* Skip over "function" tag and function name (which are guaranteed to be
>> + * present by the above PARTIAL_MATCH call).
>> + */
>> + exec_node *node = ((s_list *) expr)->subexpressions.head->next->next;
>> + for (/* nothing */; !node->is_tail_sentinel(); node = node->next) {
>> + s_expression *s_sig = (s_expression *) node;
>
> This won't behave the same in the (bug) case that the list has too few
> elements. If the list is empty or as only one element, there will be a
> NULL deref here somewhere. I believe the iterator version was safe
> against this.
>
> Do we have some pre-existing guarantee that the list has enough elements?
Yes. Above:
s_pattern pat[] = { "function", name };
if (!PARTIAL_MATCH(expr, pat)) {
ir_read_error(expr, "Expected (function <name> (signature ...) ...)");
return NULL;
}
If the list doesn't match the (partial) S-Expression
(function <name> ...)
we would have bailed by now. So the list is guaranteed to have at least
two elements.
>> read_function_sig(f, s_sig, skip_body);
>> }
>> return added ? f : NULL;
>> @@ -249,9 +250,10 @@ ir_reader::read_function_sig(ir_function *f,
>> s_expression *expr, bool skip_body)
>> exec_list hir_parameters;
>> state->symbols->push_scope();
>>
>> - exec_list_iterator it = paramlist->subexpressions.iterator();
>> - for (it.next() /* skip "parameters" */; it.has_next(); it.next()) {
>> - ir_variable *var = read_declaration((s_expression *) it.get());
>> + /* Skip over the "parameters" tag. */
>> + exec_node *node = paramlist->subexpressions.head->next;
>> + for (/* nothing */; !node->is_tail_sentinel(); node = node->next) {
>> + ir_variable *var = read_declaration((s_expression *) node);
>> if (var == NULL)
>> return;
>>
>>
>
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