[Mesa-dev] [PATCH] gallium/ttn: add support for temp arrays
Eric Anholt
eric at anholt.net
Wed Apr 8 08:14:46 PDT 2015
Rob Clark <robdclark at gmail.com> writes:
> From: Rob Clark <robclark at freedesktop.org>
>
> Since the rest of NIR really would rather have these as variables rather
> than registers, create a nir_variable per array. But rather than
> completely re-arrange ttn to be variable based rather than register
> based, keep the registers. In the cases where there is a matching var
> for the reg, ttn_emit_instruction will append the appropriate intrinsic
> to get things back from the shadow reg into the variable.
>
> NOTE: this doesn't quite handle TEMP[ADDR[]] when the DCL doesn't give
> an array id. But those just kinda suck, and should really go away.
> AFAICT we don't get those from glsl. Might be an issue for some other
> state tracker.
>
> v2: rework to use load_var/store_var with deref chains
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
> src/gallium/auxiliary/nir/tgsi_to_nir.c | 122 +++++++++++++++++++++++++++-----
> 1 file changed, 103 insertions(+), 19 deletions(-)
>
> diff --git a/src/gallium/auxiliary/nir/tgsi_to_nir.c b/src/gallium/auxiliary/nir/tgsi_to_nir.c
> index da935a4..f4c0bad 100644
> --- a/src/gallium/auxiliary/nir/tgsi_to_nir.c
> +++ b/src/gallium/auxiliary/nir/tgsi_to_nir.c
> @@ -44,6 +44,7 @@
> struct ttn_reg_info {
> /** nir register containing this TGSI index. */
> nir_register *reg;
> + nir_variable *var;
> /** Offset (in vec4s) from the start of var for this TGSI index. */
> int offset;
> };
> @@ -121,22 +122,29 @@ ttn_emit_declaration(struct ttn_compile *c)
>
> if (file == TGSI_FILE_TEMPORARY) {
> nir_register *reg;
> - if (c->scan->indirect_files & (1 << file)) {
> + nir_variable *var = NULL;
> +
> + if (decl->Declaration.Array) {
> + /* for arrays, the register created just serves as a
> + * shadow register. We append intrinsic_store_global
> + * after the tgsi instruction is translated to move
> + * back from the shadow register to the variable
> + */
> + var = rzalloc(b->shader, nir_variable);
> +
> + var->type = glsl_array_type(glsl_vec4_type(), array_size);
> + var->data.mode = nir_var_global;
> + var->name = ralloc_asprintf(var, "arr_%d", decl->Array.ArrayID);
> +
> + exec_list_push_tail(&b->shader->globals, &var->node);
> + }
> +
> + for (i = 0; i < array_size; i++) {
> reg = nir_local_reg_create(b->impl);
> reg->num_components = 4;
> - reg->num_array_elems = array_size;
> -
> - for (i = 0; i < array_size; i++) {
> - c->temp_regs[decl->Range.First + i].reg = reg;
> - c->temp_regs[decl->Range.First + i].offset = i;
> - }
> - } else {
> - for (i = 0; i < array_size; i++) {
> - reg = nir_local_reg_create(b->impl);
> - reg->num_components = 4;
> - c->temp_regs[decl->Range.First + i].reg = reg;
> - c->temp_regs[decl->Range.First + i].offset = 0;
> - }
> + c->temp_regs[decl->Range.First + i].reg = reg;
> + c->temp_regs[decl->Range.First + i].var = var;
> + c->temp_regs[decl->Range.First + i].offset = i;
Continuing to use array_size here doesn't make any sense to me, since if
you're not handling variable array indices when generating stores into
the array. So all you want is a single vec4 reg available so that you
have something that our ALU op generation can do writemasked stores
into, and you're picking an arbitrary one of them in ttn_get_dest().
I think this would make a ton more sense if ttn_get_dest() just returned
a new vec4 local reg for the temporary, instead of having this
sort-of-shadow thing.
> }
> } else if (file == TGSI_FILE_ADDRESS) {
> c->addr_reg = nir_local_reg_create(b->impl);
> @@ -245,6 +253,32 @@ ttn_emit_immediate(struct ttn_compile *c)
> static nir_src *
> ttn_src_for_indirect(struct ttn_compile *c, struct tgsi_ind_register *indirect);
>
> +/* generate either a constant or indirect deref chain for accessing an
> + * array variable.
> + */
> +static nir_deref_var *
> +ttn_array_deref(struct ttn_compile *c, nir_variable *var, unsigned offset,
> + struct tgsi_ind_register *indirect)
> +{
> + nir_builder *b = &c->build;
> + nir_deref_var *deref = nir_deref_var_create(b->shader, var);
> + nir_deref_array *arr = nir_deref_array_create(b->shader);
> +
> + arr->base_offset = offset;
> + arr->deref.type = glsl_get_array_element(var->type);
> +
> + if (indirect) {
> + arr->deref_array_type = nir_deref_array_type_indirect;
> + arr->indirect = nir_src_for_reg(c->addr_reg);
> + } else {
> + arr->deref_array_type = nir_deref_array_type_direct;
> + }
> +
> + deref->deref.child = &arr->deref;
> +
> + return deref;
> +}
> +
> static nir_src
> ttn_src_for_file_and_index(struct ttn_compile *c, unsigned file, unsigned index,
> struct tgsi_ind_register *indirect)
> @@ -256,10 +290,25 @@ ttn_src_for_file_and_index(struct ttn_compile *c, unsigned file, unsigned index,
>
> switch (file) {
> case TGSI_FILE_TEMPORARY:
> - src.reg.reg = c->temp_regs[index].reg;
> - src.reg.base_offset = c->temp_regs[index].offset;
> - if (indirect)
> - src.reg.indirect = ttn_src_for_indirect(c, indirect);
> + if (c->temp_regs[index].var) {
> + unsigned offset = c->temp_regs[index].offset;
> + nir_variable *var = c->temp_regs[index].var;
> + nir_intrinsic_instr *load;
> +
> + load = nir_intrinsic_instr_create(b->shader,
> + nir_intrinsic_load_var);
> + load->num_components = 4;
> + load->variables[0] = ttn_array_deref(c, var, offset, indirect);
> +
> + nir_ssa_dest_init(&load->instr, &load->dest, 4, NULL);
> + nir_instr_insert_after_cf_list(b->cf_node_list, &load->instr);
> +
> + src = nir_src_for_ssa(&load->dest.ssa);
> +
> + } else {
> + assert(!indirect);
> + src.reg.reg = c->temp_regs[index].reg;
> + }
> break;
>
> case TGSI_FILE_ADDRESS:
> @@ -363,6 +412,21 @@ ttn_get_dest(struct ttn_compile *c, struct tgsi_full_dst_register *tgsi_fdst)
> return dest;
> }
I don't see where you deleted the "if (tgsi_dst->Indirect)" line in
ttn_get_dest, so I'm confused how this works at all since your variable
stores don't handle the indirect.
>
> +static nir_variable *
> +ttn_get_var(struct ttn_compile *c, struct tgsi_full_dst_register *tgsi_fdst)
> +{
> + struct tgsi_dst_register *tgsi_dst = &tgsi_fdst->Register;
> + unsigned index = tgsi_dst->Index;
> +
> + if (tgsi_dst->File == TGSI_FILE_TEMPORARY) {
> + return c->temp_regs[index].var;
> + } else if (tgsi_dst->File == TGSI_FILE_OUTPUT) {
> + return c->output_regs[index].var;
> + }
> +
> + return NULL;
> +}
> +
> static nir_ssa_def *
> ttn_get_src(struct ttn_compile *c, struct tgsi_full_src_register *tgsi_fsrc)
> {
> @@ -1133,6 +1197,7 @@ ttn_emit_instruction(struct ttn_compile *c)
> struct tgsi_full_instruction *tgsi_inst = &c->token->FullInstruction;
> unsigned i;
> unsigned tgsi_op = tgsi_inst->Instruction.Opcode;
> + struct tgsi_full_dst_register *tgsi_dst = &tgsi_inst->Dst[0];
>
> if (tgsi_op == TGSI_OPCODE_END)
> return;
> @@ -1141,7 +1206,7 @@ ttn_emit_instruction(struct ttn_compile *c)
> for (i = 0; i < TGSI_FULL_MAX_SRC_REGISTERS; i++) {
> src[i] = ttn_get_src(c, &tgsi_inst->Src[i]);
> }
> - nir_alu_dest dest = ttn_get_dest(c, &tgsi_inst->Dst[0]);
> + nir_alu_dest dest = ttn_get_dest(c, tgsi_dst);
>
> switch (tgsi_op) {
> case TGSI_OPCODE_RSQ:
> @@ -1331,6 +1396,25 @@ ttn_emit_instruction(struct ttn_compile *c)
> assert(!dest.dest.is_ssa);
> ttn_move_dest(b, dest, nir_fsat(b, ttn_src_for_dest(b, &dest)));
> }
> +
> + /* if the dst has a matching var, append store_global to move
> + * output from reg to var
> + */
> + nir_variable *var = ttn_get_var(c, tgsi_dst);
> + if (var) {
> + unsigned index = tgsi_dst->Register.Index;
> + unsigned offset = c->temp_regs[index].offset;
> + nir_intrinsic_instr *store =
> + nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_var);
> + struct tgsi_ind_register *indirect = tgsi_dst->Register.Indirect ?
> + &tgsi_dst->Indirect : NULL;
> +
> + store->num_components = 4;
> + store->variables[0] = ttn_array_deref(c, var, offset, indirect);
> + store->src[0] = nir_src_for_reg(dest.dest.reg.reg);
> +
> + nir_instr_insert_after_cf_list(b->cf_node_list, &store->instr);
> + }
> }
What about a destination with a writemask? You'd need to load from the
var and merge in before storing.
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