[Mesa-dev] [PATCH 094/133] nir: Add a pass to lower global variables to local variables

Jason Ekstrand jason at jlekstrand.net
Tue Jan 6 15:32:27 PST 2015


On Sun, Jan 4, 2015 at 7:24 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:

>
>
> On Tue, Dec 16, 2014 at 1:11 AM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
>
>> ---
>>  src/glsl/Makefile.sources                     |   1 +
>>  src/glsl/nir/nir.h                            |   2 +
>>  src/glsl/nir/nir_lower_global_vars_to_local.c | 107
>> ++++++++++++++++++++++++++
>>  3 files changed, 110 insertions(+)
>>  create mode 100644 src/glsl/nir/nir_lower_global_vars_to_local.c
>>
>> diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
>> index 53c3e98..3f5c0bd 100644
>> --- a/src/glsl/Makefile.sources
>> +++ b/src/glsl/Makefile.sources
>> @@ -22,6 +22,7 @@ NIR_FILES = \
>>         $(GLSL_SRCDIR)/nir/nir_intrinsics.h \
>>         $(GLSL_SRCDIR)/nir/nir_live_variables.c \
>>         $(GLSL_SRCDIR)/nir/nir_lower_atomics.c \
>> +       $(GLSL_SRCDIR)/nir/nir_lower_global_vars_to_local.c \
>>         $(GLSL_SRCDIR)/nir/nir_lower_locals_to_regs.c \
>>         $(GLSL_SRCDIR)/nir/nir_lower_io.c \
>>         $(GLSL_SRCDIR)/nir/nir_lower_samplers.cpp \
>> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
>> index ec9ce07..30146d6 100644
>> --- a/src/glsl/nir/nir.h
>> +++ b/src/glsl/nir/nir.h
>> @@ -1358,6 +1358,8 @@ void nir_dump_cfg(nir_shader *shader, FILE *fp);
>>
>>  void nir_split_var_copies(nir_shader *shader);
>>
>> +void nir_lower_global_vars_to_local(nir_shader *shader);
>> +
>>  void nir_lower_locals_to_regs(nir_shader *shader);
>>
>>  void nir_lower_io(nir_shader *shader);
>> diff --git a/src/glsl/nir/nir_lower_global_vars_to_local.c
>> b/src/glsl/nir/nir_lower_global_vars_to_local.c
>> new file mode 100644
>> index 0000000..ec23a0a
>> --- /dev/null
>> +++ b/src/glsl/nir/nir_lower_global_vars_to_local.c
>> @@ -0,0 +1,107 @@
>> +/*
>> + * Copyright © 2014 Intel Corporation
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining
>> a
>> + * copy of this software and associated documentation files (the
>> "Software"),
>> + * to deal in the Software without restriction, including without
>> limitation
>> + * the rights to use, copy, modify, merge, publish, distribute,
>> sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice (including the
>> next
>> + * paragraph) shall be included in all copies or substantial portions of
>> the
>> + * Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
>> EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT
>> SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> ARISING
>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
>> DEALINGS
>> + * IN THE SOFTWARE.
>> + *
>> + * Authors:
>> + *    Jason Ekstrand (jason at jlekstrand.net)
>> + *
>> + */
>> +
>> +/*
>> + * This lowering pass detects when a global variable is only being used
>> by
>> + * one function and makes it local to that function
>> + */
>> +
>> +#include "nir.h"
>> +
>> +struct global_to_local_state {
>> +   nir_function_impl *impl;
>> +   /* A hash table keyed on variable pointers that stores the unique
>> +    * nir_function_impl that uses the given variable.  If a variable is
>> +    * used in multiple functions, the data for the given key will be
>> NULL.
>> +    */
>> +   struct hash_table *var_func_table;
>> +};
>> +
>> +static bool
>> +mark_global_var_uses_block(nir_block *block, void *void_state)
>> +{
>> +   struct global_to_local_state *state = void_state;
>> +
>> +   nir_foreach_instr(block, instr) {
>> +      if (instr->type != nir_instr_type_intrinsic)
>> +         continue;
>> +
>> +      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
>> +      unsigned num_vars =
>> nir_intrinsic_infos[intrin->intrinsic].num_variables;
>> +
>> +      for (unsigned i = 0; i < num_vars; i++) {
>> +         nir_variable *var = intrin->variables[i]->var;
>> +         if (var->data.mode != nir_var_global)
>> +            continue;
>> +
>> +         uint32_t hash = _mesa_hash_pointer(var);
>> +         struct hash_entry *entry =
>> +            _mesa_hash_table_search(state->var_func_table, hash, var);
>> +
>> +         if (entry) {
>> +            if (entry->data != state->impl)
>> +               entry->data = NULL;
>> +         }
>> +
>> +         _mesa_hash_table_insert(state->var_func_table, hash, var,
>> state->impl);
>>
>
> I think you should be doing:
>
> if (entry) {
>    ...
> } else {
>    _mesa_hash_table_insert(state->var_func_table, hash, var, state->impl);
> }
>

Yup.  Fixed.


>
>
>> +      }
>> +   }
>> +
>> +   return true;
>> +}
>> +
>> +void
>> +nir_lower_global_vars_to_local(nir_shader *shader)
>> +{
>> +   struct global_to_local_state state;
>> +
>> +   state.var_func_table = _mesa_hash_table_create(NULL,
>> +
>> _mesa_key_pointer_equal);
>> +
>> +   nir_foreach_overload(shader, overload) {
>> +      if (overload->impl) {
>> +         state.impl = overload->impl;
>> +         nir_foreach_block(overload->impl, mark_global_var_uses_block,
>> &state);
>> +      }
>> +   }
>> +
>> +   struct hash_entry *entry;
>> +   hash_table_foreach(state.var_func_table, entry) {
>> +      nir_variable *var = (void *)entry->key;
>> +      nir_function_impl *impl = entry->data;
>> +
>> +      assert(var->data.mode == nir_var_global);
>> +
>> +      if (impl != NULL) {
>> +         exec_node_remove(&var->node);
>> +         var->data.mode = nir_var_local;
>> +         exec_list_push_tail(&impl->locals, &var->node);
>> +      }
>> +   }
>> +
>> +   _mesa_hash_table_destroy(state.var_func_table, NULL);
>> +}
>> --
>> 2.2.0
>>
>> _______________________________________________
>> mesa-dev mailing list
>> mesa-dev at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>
>
>
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