Module: Mesa Branch: main Commit: f92738eaaabb0ce9ca34f6cbe34824cb7925bb77 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=f92738eaaabb0ce9ca34f6cbe34824cb7925bb77
Author: Alyssa Rosenzweig <[email protected]> Date: Sun Feb 19 15:29:19 2023 -0500 agx: Handle fragment shader side effects Fragment shaders with side effects need to be lowered to ensure they execute for all shaded pixels but no helper threads. Add a lowering pass to handle this. Fixes dEQP-GLES31.functional.shaders.opaque_type_indexing.atomic_counter.const_literal_fragment Signed-off-by: Alyssa Rosenzweig <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21712> --- src/asahi/compiler/agx_compile.c | 3 +- src/asahi/compiler/agx_compiler.h | 1 + src/asahi/compiler/agx_nir_lower_frag_sidefx.c | 78 ++++++++++++++++++++++++++ src/asahi/compiler/meson.build | 1 + 4 files changed, 82 insertions(+), 1 deletion(-) diff --git a/src/asahi/compiler/agx_compile.c b/src/asahi/compiler/agx_compile.c index 7f9358ca71e..ca055fb9e08 100644 --- a/src/asahi/compiler/agx_compile.c +++ b/src/asahi/compiler/agx_compile.c @@ -2239,7 +2239,9 @@ agx_preprocess_nir(nir_shader *nir, bool support_lod_bias) NIR_PASS_V(nir, nir_lower_vars_to_ssa); NIR_PASS_V(nir, nir_lower_io, nir_var_shader_in | nir_var_shader_out, glsl_type_size, 0); + NIR_PASS_V(nir, nir_lower_ssbo); if (nir->info.stage == MESA_SHADER_FRAGMENT) { + NIR_PASS_V(nir, agx_nir_lower_frag_sidefx); NIR_PASS_V(nir, agx_nir_lower_zs_emit); /* Interpolate varyings at fp16 and write to the tilebuffer at fp16. As an @@ -2293,7 +2295,6 @@ agx_preprocess_nir(nir_shader *nir, bool support_lod_bias) NIR_PASS_V(nir, nir_opt_move, move_all); NIR_PASS_V(nir, agx_nir_lower_ubo); NIR_PASS_V(nir, agx_nir_lower_shared_bitsize); - NIR_PASS_V(nir, nir_lower_ssbo); } void diff --git a/src/asahi/compiler/agx_compiler.h b/src/asahi/compiler/agx_compiler.h index 031733e0626..25ae85d2d9a 100644 --- a/src/asahi/compiler/agx_compiler.h +++ b/src/asahi/compiler/agx_compiler.h @@ -834,6 +834,7 @@ bool agx_nir_lower_load_mask(nir_shader *shader); bool agx_nir_lower_address(nir_shader *shader); bool agx_nir_lower_ubo(nir_shader *shader); bool agx_nir_lower_shared_bitsize(nir_shader *shader); +bool agx_nir_lower_frag_sidefx(nir_shader *s); #ifdef __cplusplus } /* extern C */ diff --git a/src/asahi/compiler/agx_nir_lower_frag_sidefx.c b/src/asahi/compiler/agx_nir_lower_frag_sidefx.c new file mode 100644 index 00000000000..f2615871cdc --- /dev/null +++ b/src/asahi/compiler/agx_nir_lower_frag_sidefx.c @@ -0,0 +1,78 @@ +/* + * Copyright 2022 Alyssa Rosenzweig + * SPDX-License-Identifier: MIT + */ + +#include "compiler/nir/nir.h" +#include "compiler/nir/nir_builder.h" +#include "agx_compiler.h" + +/* Fragment shaders with side effects require special handling to ensure the + * side effects execute as intended. By default, they require late depth + * testing, to ensure the side effects happen even for killed pixels. To handle, + * the driver inserts a dummy `gl_FragDepth = gl_Position.z` in shaders that + * don't otherwise write their depth, forcing a late depth test. + * + * For side effects with force early testing forced, the sample mask is written + * at the *beginning* of the shader (TODO: handle). + */ + +static bool +pass(struct nir_builder *b, nir_instr *instr, void *data) +{ + if (instr->type != nir_instr_type_intrinsic) + return false; + + nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); + if (intr->intrinsic != nir_intrinsic_store_output) + return false; + + /* Only lower once */ + bool *done = data; + if (*done) + return false; + *done = true; + + b->cursor = nir_before_instr(instr); + nir_ssa_def *zero = nir_imm_int(b, 0); + nir_ssa_def *pixel = nir_load_barycentric_pixel(b, 32, .interp_mode = 1); + + nir_ssa_def *position = + nir_load_interpolated_input(b, 1, 32, pixel, zero, .component = 2 /* Z */, + .dest_type = nir_type_float32, + .io_semantics = { + .location = VARYING_SLOT_POS, + .num_slots = 1, + }); + + nir_store_output(b, position, zero, + .io_semantics.location = FRAG_RESULT_DEPTH, + .write_mask = BITFIELD_MASK(1), + .src_type = nir_type_float32); + + b->shader->info.inputs_read |= BITFIELD64_BIT(VARYING_SLOT_POS); + b->shader->info.outputs_written |= BITFIELD64_BIT(FRAG_RESULT_DEPTH); + return true; +} + +bool +agx_nir_lower_frag_sidefx(nir_shader *s) +{ + assert(s->info.stage == MESA_SHADER_FRAGMENT); + + /* If there are no side effects, there's nothing to lower */ + if (!s->info.writes_memory) + return false; + + /* Lower writes from helper invocations with the common pass */ + NIR_PASS_V(s, nir_lower_helper_writes, false); + + /* If depth/stencil feedback is already used, we're done */ + if (s->info.outputs_written & (BITFIELD64_BIT(FRAG_RESULT_STENCIL) | + BITFIELD64_BIT(FRAG_RESULT_DEPTH))) + return false; + + bool done = false; + return nir_shader_instructions_pass( + s, pass, nir_metadata_block_index | nir_metadata_dominance, &done); +} diff --git a/src/asahi/compiler/meson.build b/src/asahi/compiler/meson.build index 42af74d2d05..4a751e24e39 100644 --- a/src/asahi/compiler/meson.build +++ b/src/asahi/compiler/meson.build @@ -25,6 +25,7 @@ libasahi_agx_files = files( 'agx_liveness.c', 'agx_insert_waits.c', 'agx_nir_lower_address.c', + 'agx_nir_lower_frag_sidefx.c', 'agx_nir_lower_zs_emit.c', 'agx_nir_lower_texture.c', 'agx_nir_lower_load_mask.c',
