[Mesa-dev] [PATCH] nir: Use helper macros for dealing with VLAs.
Jason Ekstrand
jason at jlekstrand.net
Tue Mar 3 09:38:50 PST 2015
LGTM. I would still rather do the allocation in live_variables not on the
stack, but I can clean that up later.
Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com>
On Tue, Mar 3, 2015 at 5:19 AM, Jose Fonseca <jfonseca at vmware.com> wrote:
> v2:
> - Single statement, by using memset return value as suggested by Ian
> Romanick.
> - No internal declaration, as suggested by Jason Ekstrand.
> - Move macros to a header.
> ---
> src/glsl/nir/nir_from_ssa.c | 23 ++++++---------
> src/glsl/nir/nir_live_variables.c | 4 +--
> src/glsl/nir/nir_lower_vars_to_ssa.c | 12 +++-----
> src/glsl/nir/nir_vla.h | 54
> ++++++++++++++++++++++++++++++++++++
> 4 files changed, 69 insertions(+), 24 deletions(-)
> create mode 100644 src/glsl/nir/nir_vla.h
>
> diff --git a/src/glsl/nir/nir_from_ssa.c b/src/glsl/nir/nir_from_ssa.c
> index 66339f3..c3090fb 100644
> --- a/src/glsl/nir/nir_from_ssa.c
> +++ b/src/glsl/nir/nir_from_ssa.c
> @@ -26,7 +26,7 @@
> */
>
> #include "nir.h"
> -#include "c99_alloca.h"
> +#include "nir_vla.h"
>
> /*
> * This file implements an out-of-SSA pass as described in "Revisiting
> @@ -182,7 +182,7 @@ merge_merge_sets(merge_set *a, merge_set *b)
> static bool
> merge_sets_interfere(merge_set *a, merge_set *b)
> {
> - merge_node **dom = alloca((a->size + b->size) * sizeof *dom);
> + NIR_VLA(merge_node *, dom, a->size + b->size);
> int dom_idx = -1;
>
> struct exec_node *an = exec_list_get_head(&a->nodes);
> @@ -674,21 +674,16 @@ resolve_parallel_copy(nir_parallel_copy_instr *pcopy,
> }
>
> /* The register/source corresponding to the given index */
> - nir_src *values = alloca(num_copies * 2 * sizeof *values);
> - memset(values, 0, num_copies * 2 * sizeof *values);
> + NIR_VLA_ZERO(nir_src, values, num_copies * 2);
>
> - /* The current location of a given piece of data */
> - int *loc = alloca(num_copies * 2 * sizeof *loc);
> + /* The current location of a given piece of data. We will use -1 for
> "null" */
> + NIR_VLA_FILL(int, loc, num_copies * 2, -1);
>
> - /* The piece of data that the given piece of data is to be copied from
> */
> - int *pred = alloca(num_copies * 2 * sizeof *pred);
> -
> - /* Initialize loc and pred. We will use -1 for "null" */
> - memset(loc, -1, num_copies * 2 * sizeof *loc);
> - memset(pred, -1, num_copies * 2 * sizeof *pred);
> + /* The piece of data that the given piece of data is to be copied
> from. We will use -1 for "null" */
> + NIR_VLA_FILL(int, pred, num_copies * 2, -1);
>
> /* The destinations we have yet to properly fill */
> - int *to_do = alloca(num_copies * 2 * sizeof *to_do);
> + NIR_VLA(int, to_do, num_copies * 2);
> int to_do_idx = -1;
>
> /* Now we set everything up:
> @@ -738,7 +733,7 @@ resolve_parallel_copy(nir_parallel_copy_instr *pcopy,
> }
>
> /* Currently empty destinations we can go ahead and fill */
> - int *ready = alloca(num_copies * 2 * sizeof *ready);
> + NIR_VLA(int, ready, num_copies * 2);
> int ready_idx = -1;
>
> /* Mark the ones that are ready for copying. We know an index is a
> diff --git a/src/glsl/nir/nir_live_variables.c
> b/src/glsl/nir/nir_live_variables.c
> index b57ca3a..1c96dcf 100644
> --- a/src/glsl/nir/nir_live_variables.c
> +++ b/src/glsl/nir/nir_live_variables.c
> @@ -26,7 +26,7 @@
>
> #include "nir.h"
> #include "nir_worklist.h"
> -#include "c99_alloca.h"
> +#include "nir_vla.h"
>
> /*
> * Basic liveness analysis. This works only in SSA form.
> @@ -131,7 +131,7 @@ static bool
> propagate_across_edge(nir_block *pred, nir_block *succ,
> struct live_variables_state *state)
> {
> - BITSET_WORD *live = alloca(state->bitset_words * sizeof *live);
> + NIR_VLA(BITSET_WORD, live, state->bitset_words);
> memcpy(live, succ->live_in, state->bitset_words * sizeof *live);
>
> nir_foreach_instr(succ, instr) {
> diff --git a/src/glsl/nir/nir_lower_vars_to_ssa.c
> b/src/glsl/nir/nir_lower_vars_to_ssa.c
> index f54d1b7..9e9a418 100644
> --- a/src/glsl/nir/nir_lower_vars_to_ssa.c
> +++ b/src/glsl/nir/nir_lower_vars_to_ssa.c
> @@ -26,8 +26,7 @@
> */
>
> #include "nir.h"
> -
> -#include "c99_alloca.h"
> +#include "nir_vla.h"
>
>
> struct deref_node {
> @@ -902,8 +901,8 @@ rename_variables_block(nir_block *block, struct
> lower_variables_state *state)
> static void
> insert_phi_nodes(struct lower_variables_state *state)
> {
> - unsigned *work = alloca(state->impl->num_blocks * sizeof *work);
> - unsigned *has_already = alloca(state->impl->num_blocks * sizeof
> *has_already);
> + NIR_VLA_ZERO(unsigned, work, state->impl->num_blocks);
> + NIR_VLA_ZERO(unsigned, has_already, state->impl->num_blocks);
>
> /*
> * Since the work flags already prevent us from inserting a node that
> has
> @@ -913,10 +912,7 @@ insert_phi_nodes(struct lower_variables_state *state)
> * function. So all we need to handle W is an array and a pointer to
> the
> * next element to be inserted and the next element to be removed.
> */
> - nir_block **W = alloca(state->impl->num_blocks * sizeof *W);
> -
> - memset(work, 0, state->impl->num_blocks * sizeof *work);
> - memset(has_already, 0, state->impl->num_blocks * sizeof *has_already);
> + NIR_VLA(nir_block *, W, state->impl->num_blocks);
>
> unsigned w_start, w_end;
> unsigned iter_count = 0;
> diff --git a/src/glsl/nir/nir_vla.h b/src/glsl/nir/nir_vla.h
> new file mode 100644
> index 0000000..7537833
> --- /dev/null
> +++ b/src/glsl/nir/nir_vla.h
> @@ -0,0 +1,54 @@
>
> +/**************************************************************************
> + *
> + * Copyright 2015 VMware, Inc.
> + * All Rights Reserved.
> + *
> + * 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, sub license, 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 NON-INFRINGEMENT.
> + * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS 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.
> + *
> +
> **************************************************************************/
> +
> +#pragma once
> +
> +
> +#include "c99_alloca.h"
> +
> +
> +/* Declare a variable length array, with no initialization */
> +#define NIR_VLA(_type, _name, _length) \
> + _type *_name = alloca((_length) * sizeof *_name)
> +
> +
> +/* Declare a variable length array, and initialize it with the given byte.
> + *
> + * _length is evaluated twice, so expressions with side-effects must be
> + * avoided.
> + */
> +#define NIR_VLA_FILL(_type, _name, _length, _byte) \
> + _type *_name = memset(alloca((_length) * sizeof *_name), _byte,
> (_length) * sizeof *_name)
> +
> +
> +/* Declare a variable length array, and zero it.
> + *
> + * Just like NIR_VLA_FILL, _length is evaluated twice, so expressions with
> + * side-effects must be avoided.
> + */
> +#define NIR_VLA_ZERO(_type, _name, _length) \
> + NIR_VLA_FILL(_type, _name, _length, 0)
> --
> 2.1.0
>
>
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