On Sun, Dec 27, 2015 at 10:15 AM, Connor Abbott <cwabbo...@gmail.com> wrote:
> On Sat, Dec 26, 2015 at 2:09 PM, Jason Ekstrand <ja...@jlekstrand.net>
> wrote:
> > This commit adds a new NIR pass that lowers all function calls away by
> > inlining the functions.
> > ---
> >
> > There are still two things missing here:
> >
> > 1) We really shouldn't do the inline recursively. We should keep a
> > hash-table of inlined versions or something.
>
> I don't think we need anything so complicated. We're collapsing the
> DAG of functions, so we just need a simple DFS: we should inline the
> callees before inlining the caller. We could keep a record of the
> already-inlined functions, but if we visit an already-inlined function
> we wouldn't do anything so it would only save us the cost of walking
> over that function.
>
Yes, that's what we want to do for the "inline the whole shader" case.
What if we want only want to inline part of it? Would that ever seriously
happen? I don't know. We probably also want to delete all of the "extra"
functions while we're at it. How do we specify the unique entrypoint? No,
"main" isn't sufficient.
--Jason
>
> >
> > 2) It doesn't properly handle things like samplers as parameters. Since
> > those can only be "in" parameters, I had thought about treating the
> > variable as a "proxy" and going through and rewriting all of the
> derefs
> > that use it. We could do the same thing for regular parameters when
> a
> > shadow isn't needed.
> >
> > Still, I thought it was worth sending out because it does work for most
> > cases.
> >
> > src/glsl/Makefile.sources | 1 +
> > src/glsl/nir/nir.h | 3 +
> > src/glsl/nir/nir_inline_functions.c | 138
> ++++++++++++++++++++++++++++++++++++
> > 3 files changed, 142 insertions(+)
> > create mode 100644 src/glsl/nir/nir_inline_functions.c
> >
> > diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
> > index fa3868c..c271afd 100644
> > --- a/src/glsl/Makefile.sources
> > +++ b/src/glsl/Makefile.sources
> > @@ -35,6 +35,7 @@ NIR_FILES = \
> > nir/nir_dominance.c \
> > nir/nir_from_ssa.c \
> > nir/nir_gs_count_vertices.c \
> > + nir/nir_inline_functions.c \
> > nir/nir_intrinsics.c \
> > nir/nir_intrinsics.h \
> > nir/nir_instr_set.c \
> > diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> > index 2e29617..437f63a 100644
> > --- a/src/glsl/nir/nir.h
> > +++ b/src/glsl/nir/nir.h
> > @@ -1938,6 +1938,9 @@ bool nir_split_var_copies(nir_shader *shader);
> > bool nir_lower_returns_impl(nir_function_impl *impl);
> > bool nir_lower_returns(nir_shader *shader);
> >
> > +bool nir_inline_functions_impl(nir_function_impl *impl);
> > +bool nir_inline_functions(nir_shader *shader);
> > +
> > void nir_lower_var_copy_instr(nir_intrinsic_instr *copy, void *mem_ctx);
> > void nir_lower_var_copies(nir_shader *shader);
> >
> > diff --git a/src/glsl/nir/nir_inline_functions.c
> b/src/glsl/nir/nir_inline_functions.c
> > new file mode 100644
> > index 0000000..e7e17ca
> > --- /dev/null
> > +++ b/src/glsl/nir/nir_inline_functions.c
> > @@ -0,0 +1,138 @@
> > +/*
> > + * Copyright © 2015 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.
> > + */
> > +
> > +#include "nir.h"
> > +#include "nir_builder.h"
> > +#include "nir_control_flow.h"
> > +
> > +struct inline_functions_state {
> > + nir_function_impl *impl;
> > + nir_builder builder;
> > + bool progress;
> > +};
> > +
> > +static bool
> > +inline_functions_block(nir_block *block, void *void_state)
> > +{
> > + struct inline_functions_state *state = void_state;
> > +
> > + nir_builder *b = &state->builder;
> > +
> > + /* This is tricky. We're iterating over instructions in a block
> but, as
> > + * we go, the block and its instruction list are being split into
> > + * pieces. However, this *should* be safe since foreach_safe always
> > + * stashes the next thing in the iteration. That next thing will
> > + * properly get moved to the next block when it gets split, and we
> > + * continue iterating there.
> > + */
> > + nir_foreach_instr_safe(block, instr) {
> > + if (instr->type != nir_instr_type_call)
> > + continue;
> > +
> > + state->progress = true;
> > +
> > + nir_call_instr *call = nir_instr_as_call(instr);
> > + assert(call->callee->impl);
> > +
> > + nir_function_impl *callee_copy =
> > + nir_function_impl_clone(call->callee->impl);
> > +
> > + exec_list_append(&state->impl->locals, &callee_copy->locals);
> > + exec_list_append(&state->impl->registers,
> &callee_copy->registers);
> > +
> > + b->cursor = nir_before_instr(&call->instr);
> > +
> > + /* Add copies of all in parameters */
> > + assert(call->num_params == callee_copy->num_params);
> > + for (unsigned i = 0; i < callee_copy->num_params; i++) {
> > + /* Only in or inout parameters */
> > + if (call->callee->params[i].param_type == nir_parameter_out)
> > + continue;
> > +
> > + nir_copy_deref_var(b, nir_deref_var_create(b->shader,
> > +
> callee_copy->params[i]),
> > + call->params[i]);
> > + }
> > +
> > + /* Pluck the body out of the function and place it here */
> > + nir_cf_list body;
> > + nir_cf_list_extract(&body, &callee_copy->body);
> > + nir_cf_reinsert(&body, b->cursor);
> > +
> > + b->cursor = nir_before_instr(&call->instr);
> > +
> > + /* Add copies of all out parameters and the return */
> > + assert(call->num_params == callee_copy->num_params);
> > + for (unsigned i = 0; i < callee_copy->num_params; i++) {
> > + /* Only out or inout parameters */
> > + if (call->callee->params[i].param_type == nir_parameter_in)
> > + continue;
> > +
> > + nir_copy_deref_var(b, call->params[i],
> > + nir_deref_var_create(b->shader,
> > +
> callee_copy->params[i]));
> > + }
> > + if (!glsl_type_is_void(call->callee->return_type)) {
> > + nir_copy_deref_var(b, call->return_deref,
> > + nir_deref_var_create(b->shader,
> > +
> callee_copy->return_var));
> > + }
> > +
> > + nir_instr_remove(&call->instr);
> > + }
> > +
> > + return true;
> > +}
> > +
> > +bool
> > +nir_inline_functions_impl(nir_function_impl *impl)
> > +{
> > + struct inline_functions_state state;
> > +
> > + state.progress = false;
> > + state.impl = impl;
> > + nir_builder_init(&state.builder, impl);
> > +
> > + nir_foreach_block(impl, inline_functions_block, &state);
> > +
> > + /* SSA and register indices are completely messed up now */
> > + nir_index_ssa_defs(impl);
> > + nir_index_local_regs(impl);
> > +
> > + nir_metadata_preserve(impl, nir_metadata_none);
> > +
> > + return state.progress;
> > +}
> > +
> > +bool
> > +nir_inline_functions(nir_shader *shader)
> > +{
> > + bool progress = false;
> > +
> > + nir_foreach_function(shader, function) {
> > + if (function->impl)
> > + progress = nir_inline_functions_impl(function->impl) ||
> progress;
> > + }
> > +
> > + return progress;
> > +}
> > --
> > 2.5.0.400.gff86faf
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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