#include "sid.h"
#include "util/u_memory.h"
+#include "util/u_prim.h"
static LLVMValueRef get_wave_id_in_tg(struct si_shader_context *ctx)
{
return si_unpack_param(ctx, ctx->param_merged_wave_info, 24, 4);
}
+static LLVMValueRef get_tgsize(struct si_shader_context *ctx)
+{
+ return si_unpack_param(ctx, ctx->param_merged_wave_info, 28, 4);
+}
+
+static LLVMValueRef get_thread_id_in_tg(struct si_shader_context *ctx)
+{
+ LLVMBuilderRef builder = ctx->ac.builder;
+ LLVMValueRef tmp;
+ tmp = LLVMBuildMul(builder, get_wave_id_in_tg(ctx),
+ LLVMConstInt(ctx->ac.i32, 64, false), "");
+ return LLVMBuildAdd(builder, tmp, ac_get_thread_id(&ctx->ac), "");
+}
+
static LLVMValueRef ngg_get_vtx_cnt(struct si_shader_context *ctx)
{
return ac_build_bfe(&ctx->ac, ctx->gs_tg_info,
FREE(outputs);
}
+
+static LLVMValueRef
+ngg_gs_get_vertex_storage(struct si_shader_context *ctx)
+{
+ const struct si_shader_selector *sel = ctx->shader->selector;
+ const struct tgsi_shader_info *info = &sel->info;
+
+ LLVMTypeRef elements[2] = {
+ LLVMArrayType(ctx->ac.i32, 4 * info->num_outputs),
+ LLVMArrayType(ctx->ac.i8, 4),
+ };
+ LLVMTypeRef type = LLVMStructTypeInContext(ctx->ac.context, elements, 2, false);
+ type = LLVMPointerType(LLVMArrayType(type, 0), AC_ADDR_SPACE_LDS);
+ return LLVMBuildBitCast(ctx->ac.builder, ctx->gs_ngg_emit, type, "");
+}
+
+/**
+ * Return a pointer to the LDS storage reserved for the N'th vertex, where N
+ * is in emit order; that is:
+ * - during the epilogue, N is the threadidx (relative to the entire threadgroup)
+ * - during vertex emit, i.e. while the API GS shader invocation is running,
+ * N = threadidx * gs_max_out_vertices + emitidx
+ *
+ * Goals of the LDS memory layout:
+ * 1. Eliminate bank conflicts on write for geometry shaders that have all emits
+ * in uniform control flow
+ * 2. Eliminate bank conflicts on read for export if, additionally, there is no
+ * culling
+ * 3. Agnostic to the number of waves (since we don't know it before compiling)
+ * 4. Allow coalescing of LDS instructions (ds_write_b128 etc.)
+ * 5. Avoid wasting memory.
+ *
+ * We use an AoS layout due to point 4 (this also helps point 3). In an AoS
+ * layout, elimination of bank conflicts requires that each vertex occupy an
+ * odd number of dwords. We use the additional dword to store the output stream
+ * index as well as a flag to indicate whether this vertex ends a primitive
+ * for rasterization.
+ *
+ * Swizzling is required to satisfy points 1 and 2 simultaneously.
+ *
+ * Vertices are stored in export order (gsthread * gs_max_out_vertices + emitidx).
+ * Indices are swizzled in groups of 32, which ensures point 1 without
+ * disturbing point 2.
+ *
+ * \return an LDS pointer to type {[N x i32], [4 x i8]}
+ */
+static LLVMValueRef
+ngg_gs_vertex_ptr(struct si_shader_context *ctx, LLVMValueRef vertexidx)
+{
+ struct si_shader_selector *sel = ctx->shader->selector;
+ LLVMBuilderRef builder = ctx->ac.builder;
+ LLVMValueRef storage = ngg_gs_get_vertex_storage(ctx);
+
+ /* gs_max_out_vertices = 2^(write_stride_2exp) * some odd number */
+ unsigned write_stride_2exp = ffs(sel->gs_max_out_vertices) - 1;
+ if (write_stride_2exp) {
+ LLVMValueRef row =
+ LLVMBuildLShr(builder, vertexidx,
+ LLVMConstInt(ctx->ac.i32, 5, false), "");
+ LLVMValueRef swizzle =
+ LLVMBuildAnd(builder, row,
+ LLVMConstInt(ctx->ac.i32, (1u << write_stride_2exp) - 1,
+ false), "");
+ vertexidx = LLVMBuildXor(builder, vertexidx, swizzle, "");
+ }
+
+ return ac_build_gep0(&ctx->ac, storage, vertexidx);
+}
+
+static LLVMValueRef
+ngg_gs_emit_vertex_ptr(struct si_shader_context *ctx, LLVMValueRef gsthread,
+ LLVMValueRef emitidx)
+{
+ struct si_shader_selector *sel = ctx->shader->selector;
+ LLVMBuilderRef builder = ctx->ac.builder;
+ LLVMValueRef tmp;
+
+ tmp = LLVMConstInt(ctx->ac.i32, sel->gs_max_out_vertices, false);
+ tmp = LLVMBuildMul(builder, tmp, gsthread, "");
+ const LLVMValueRef vertexidx = LLVMBuildAdd(builder, tmp, emitidx, "");
+ return ngg_gs_vertex_ptr(ctx, vertexidx);
+}
+
+void gfx10_ngg_gs_emit_vertex(struct si_shader_context *ctx,
+ unsigned stream,
+ LLVMValueRef *addrs)
+{
+ const struct si_shader_selector *sel = ctx->shader->selector;
+ const struct tgsi_shader_info *info = &sel->info;
+ LLVMBuilderRef builder = ctx->ac.builder;
+ struct lp_build_if_state if_state;
+ LLVMValueRef tmp;
+ const LLVMValueRef vertexidx =
+ LLVMBuildLoad(builder, ctx->gs_next_vertex[stream], "");
+
+ /* If this thread has already emitted the declared maximum number of
+ * vertices, skip the write: excessive vertex emissions are not
+ * supposed to have any effect.
+ */
+ const LLVMValueRef can_emit =
+ LLVMBuildICmp(builder, LLVMIntULT, vertexidx,
+ LLVMConstInt(ctx->i32, sel->gs_max_out_vertices, false), "");
+
+ tmp = LLVMBuildAdd(builder, vertexidx, ctx->ac.i32_1, "");
+ tmp = LLVMBuildSelect(builder, can_emit, tmp, vertexidx, "");
+ LLVMBuildStore(builder, tmp, ctx->gs_next_vertex[stream]);
+
+ lp_build_if(&if_state, &ctx->gallivm, can_emit);
+
+ const LLVMValueRef vertexptr =
+ ngg_gs_emit_vertex_ptr(ctx, get_thread_id_in_tg(ctx), vertexidx);
+ unsigned out_idx = 0;
+ for (unsigned i = 0; i < info->num_outputs; i++) {
+ for (unsigned chan = 0; chan < 4; chan++, out_idx++) {
+ if (!(info->output_usagemask[i] & (1 << chan)) ||
+ ((info->output_streams[i] >> (2 * chan)) & 3) != stream)
+ continue;
+
+ LLVMValueRef out_val = LLVMBuildLoad(builder, addrs[4 * i + chan], "");
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implied C-style array */
+ ctx->ac.i32_0, /* first entry of struct */
+ LLVMConstInt(ctx->ac.i32, out_idx, false),
+ };
+ LLVMValueRef ptr = LLVMBuildGEP(builder, vertexptr, gep_idx, 3, "");
+
+ out_val = ac_to_integer(&ctx->ac, out_val);
+ LLVMBuildStore(builder, out_val, ptr);
+ }
+ }
+ assert(out_idx * 4 == sel->gsvs_vertex_size);
+
+ /* Determine and store whether this vertex completed a primitive. */
+ const LLVMValueRef curverts = LLVMBuildLoad(builder, ctx->gs_curprim_verts[stream], "");
+
+ tmp = LLVMConstInt(ctx->ac.i32, u_vertices_per_prim(sel->gs_output_prim) - 1, false);
+ const LLVMValueRef iscompleteprim =
+ LLVMBuildICmp(builder, LLVMIntUGE, curverts, tmp, "");
+
+ tmp = LLVMBuildAdd(builder, curverts, ctx->ac.i32_1, "");
+ LLVMBuildStore(builder, tmp, ctx->gs_curprim_verts[stream]);
+
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implied C-style array */
+ ctx->ac.i32_1, /* second struct entry */
+ LLVMConstInt(ctx->ac.i32, stream, false),
+ };
+ const LLVMValueRef primflagptr =
+ LLVMBuildGEP(builder, vertexptr, gep_idx, 3, "");
+
+ tmp = LLVMBuildZExt(builder, iscompleteprim, ctx->ac.i8, "");
+ LLVMBuildStore(builder, tmp, primflagptr);
+
+ lp_build_endif(&if_state);
+}
+
+void gfx10_ngg_gs_emit_epilogue(struct si_shader_context *ctx)
+{
+ const struct si_shader_selector *sel = ctx->shader->selector;
+ const struct tgsi_shader_info *info = &sel->info;
+ const unsigned verts_per_prim = u_vertices_per_prim(sel->gs_output_prim);
+ LLVMBuilderRef builder = ctx->ac.builder;
+ LLVMValueRef i8_0 = LLVMConstInt(ctx->ac.i8, 0, false);
+ LLVMValueRef tmp, tmp2;
+
+ /* Zero out remaining (non-emitted) primitive flags.
+ *
+ * Note: Alternatively, we could pass the relevant gs_next_vertex to
+ * the emit threads via LDS. This is likely worse in the expected
+ * typical case where each GS thread emits the full set of
+ * vertices.
+ */
+ for (unsigned stream = 0; stream < 4; ++stream) {
+ if (!info->num_stream_output_components[stream])
+ continue;
+
+ const LLVMValueRef gsthread = get_thread_id_in_tg(ctx);
+
+ ac_build_bgnloop(&ctx->ac, 5100);
+
+ const LLVMValueRef vertexidx =
+ LLVMBuildLoad(builder, ctx->gs_next_vertex[stream], "");
+ tmp = LLVMBuildICmp(builder, LLVMIntUGE, vertexidx,
+ LLVMConstInt(ctx->ac.i32, sel->gs_max_out_vertices, false), "");
+ ac_build_ifcc(&ctx->ac, tmp, 5101);
+ ac_build_break(&ctx->ac);
+ ac_build_endif(&ctx->ac, 5101);
+
+ tmp = LLVMBuildAdd(builder, vertexidx, ctx->ac.i32_1, "");
+ LLVMBuildStore(builder, tmp, ctx->gs_next_vertex[stream]);
+
+ tmp = ngg_gs_emit_vertex_ptr(ctx, gsthread, vertexidx);
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implied C-style array */
+ ctx->ac.i32_1, /* second entry of struct */
+ LLVMConstInt(ctx->ac.i32, stream, false),
+ };
+ tmp = LLVMBuildGEP(builder, tmp, gep_idx, 3, "");
+ LLVMBuildStore(builder, i8_0, tmp);
+
+ ac_build_endloop(&ctx->ac, 5100);
+ }
+
+ lp_build_endif(&ctx->merged_wrap_if_state);
+
+ ac_build_s_barrier(&ctx->ac);
+
+ const LLVMValueRef tid = get_thread_id_in_tg(ctx);
+ LLVMValueRef num_emit_threads = ngg_get_prim_cnt(ctx);
+
+ /* TODO: streamout */
+
+ /* TODO: culling */
+
+ /* Determine vertex liveness. */
+ LLVMValueRef vertliveptr = lp_build_alloca(&ctx->gallivm, ctx->ac.i1, "vertexlive");
+
+ tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, num_emit_threads, "");
+ ac_build_ifcc(&ctx->ac, tmp, 5120);
+ {
+ for (unsigned i = 0; i < verts_per_prim; ++i) {
+ const LLVMValueRef primidx =
+ LLVMBuildAdd(builder, tid,
+ LLVMConstInt(ctx->ac.i32, i, false), "");
+
+ if (i > 0) {
+ tmp = LLVMBuildICmp(builder, LLVMIntULT, primidx, num_emit_threads, "");
+ ac_build_ifcc(&ctx->ac, tmp, 5121 + i);
+ }
+
+ /* Load primitive liveness */
+ tmp = ngg_gs_vertex_ptr(ctx, primidx);
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implicit C-style array */
+ ctx->ac.i32_1, /* second value of struct */
+ ctx->ac.i32_0, /* stream 0 */
+ };
+ tmp = LLVMBuildGEP(builder, tmp, gep_idx, 3, "");
+ tmp = LLVMBuildLoad(builder, tmp, "");
+ const LLVMValueRef primlive =
+ LLVMBuildTrunc(builder, tmp, ctx->ac.i1, "");
+
+ tmp = LLVMBuildLoad(builder, vertliveptr, "");
+ tmp = LLVMBuildOr(builder, tmp, primlive, ""),
+ LLVMBuildStore(builder, tmp, vertliveptr);
+
+ if (i > 0)
+ ac_build_endif(&ctx->ac, 5121 + i);
+ }
+ }
+ ac_build_endif(&ctx->ac, 5120);
+
+ /* Inclusive scan addition across the current wave. */
+ LLVMValueRef vertlive = LLVMBuildLoad(builder, vertliveptr, "");
+ struct ac_wg_scan vertlive_scan = {};
+ vertlive_scan.op = nir_op_iadd;
+ vertlive_scan.enable_reduce = true;
+ vertlive_scan.enable_exclusive = true;
+ vertlive_scan.src = vertlive;
+ vertlive_scan.scratch = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, ctx->i32_0);
+ vertlive_scan.waveidx = get_wave_id_in_tg(ctx);
+ vertlive_scan.numwaves = get_tgsize(ctx);
+ vertlive_scan.maxwaves = 8;
+
+ ac_build_wg_scan(&ctx->ac, &vertlive_scan);
+
+ /* Skip all exports (including index exports) when possible. At least on
+ * early gfx10 revisions this is also to avoid hangs.
+ */
+ LLVMValueRef have_exports =
+ LLVMBuildICmp(builder, LLVMIntNE, vertlive_scan.result_reduce, ctx->ac.i32_0, "");
+ num_emit_threads =
+ LLVMBuildSelect(builder, have_exports, num_emit_threads, ctx->ac.i32_0, "");
+
+ /* Allocate export space. Send this message as early as possible, to
+ * hide the latency of the SQ <-> SPI roundtrip.
+ *
+ * Note: We could consider compacting primitives for export as well.
+ * PA processes 1 non-null prim / clock, but it fetches 4 DW of
+ * prim data per clock and skips null primitives at no additional
+ * cost. So compacting primitives can only be beneficial when
+ * there are 4 or more contiguous null primitives in the export
+ * (in the common case of single-dword prim exports).
+ */
+ build_sendmsg_gs_alloc_req(ctx, vertlive_scan.result_reduce, num_emit_threads);
+
+ /* Setup the reverse vertex compaction permutation. We re-use stream 1
+ * of the primitive liveness flags, relying on the fact that each
+ * threadgroup can have at most 256 threads. */
+ ac_build_ifcc(&ctx->ac, vertlive, 5130);
+ {
+ tmp = ngg_gs_vertex_ptr(ctx, vertlive_scan.result_exclusive);
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implicit C-style array */
+ ctx->ac.i32_1, /* second value of struct */
+ ctx->ac.i32_1, /* stream 1 */
+ };
+ tmp = LLVMBuildGEP(builder, tmp, gep_idx, 3, "");
+ tmp2 = LLVMBuildTrunc(builder, tid, ctx->ac.i8, "");
+ LLVMBuildStore(builder, tmp2, tmp);
+ }
+ ac_build_endif(&ctx->ac, 5130);
+
+ ac_build_s_barrier(&ctx->ac);
+
+ /* Export primitive data */
+ tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, num_emit_threads, "");
+ ac_build_ifcc(&ctx->ac, tmp, 5140);
+ {
+ struct ngg_prim prim = {};
+ prim.num_vertices = verts_per_prim;
+
+ tmp = ngg_gs_vertex_ptr(ctx, tid);
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implicit C-style array */
+ ctx->ac.i32_1, /* second value of struct */
+ ctx->ac.i32_0, /* primflag */
+ };
+ tmp = LLVMBuildGEP(builder, tmp, gep_idx, 3, "");
+ tmp = LLVMBuildLoad(builder, tmp, "");
+ prim.isnull = LLVMBuildICmp(builder, LLVMIntEQ, tmp,
+ LLVMConstInt(ctx->ac.i8, 0, false), "");
+
+ for (unsigned i = 0; i < verts_per_prim; ++i) {
+ prim.index[i] = LLVMBuildSub(builder, vertlive_scan.result_exclusive,
+ LLVMConstInt(ctx->ac.i32, verts_per_prim - i - 1, false), "");
+ prim.edgeflag[i] = ctx->ac.i1false;
+ }
+
+ build_export_prim(ctx, &prim);
+ }
+ ac_build_endif(&ctx->ac, 5140);
+
+ /* Export position and parameter data */
+ tmp = LLVMBuildICmp(builder, LLVMIntULT, tid, vertlive_scan.result_reduce, "");
+ ac_build_ifcc(&ctx->ac, tmp, 5145);
+ {
+ struct si_shader_output_values *outputs = NULL;
+ outputs = MALLOC(info->num_outputs * sizeof(outputs[0]));
+
+ tmp = ngg_gs_vertex_ptr(ctx, tid);
+ LLVMValueRef gep_idx[3] = {
+ ctx->ac.i32_0, /* implicit C-style array */
+ ctx->ac.i32_1, /* second value of struct */
+ ctx->ac.i32_1, /* stream 1: source data index */
+ };
+ tmp = LLVMBuildGEP(builder, tmp, gep_idx, 3, "");
+ tmp = LLVMBuildLoad(builder, tmp, "");
+ tmp = LLVMBuildZExt(builder, tmp, ctx->ac.i32, "");
+ const LLVMValueRef vertexptr = ngg_gs_vertex_ptr(ctx, tmp);
+
+ unsigned out_idx = 0;
+ gep_idx[1] = ctx->ac.i32_0;
+ for (unsigned i = 0; i < info->num_outputs; i++) {
+ outputs[i].semantic_name = info->output_semantic_name[i];
+ outputs[i].semantic_index = info->output_semantic_index[i];
+
+ for (unsigned j = 0; j < 4; j++, out_idx++) {
+ gep_idx[2] = LLVMConstInt(ctx->ac.i32, out_idx, false);
+ tmp = LLVMBuildGEP(builder, vertexptr, gep_idx, 3, "");
+ tmp = LLVMBuildLoad(builder, tmp, "");
+ outputs[i].values[j] = ac_to_float(&ctx->ac, tmp);
+ outputs[i].vertex_stream[j] =
+ (info->output_streams[i] >> (2 * j)) & 3;
+ }
+ }
+
+ si_llvm_export_vs(ctx, outputs, info->num_outputs);
+
+ FREE(outputs);
+ }
+ ac_build_endif(&ctx->ac, 5145);
+}
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