radeonsi: add support for interpolateAt functions (v2)

This is part of ARB_gpu_shader5, and this passes
all the piglit tests currently available.

v2: use macros from the fine derivs commit.
add comments.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/docs/GL3.txt b/docs/GL3.txt
index 15bb57f..258a6fb 100644 (file)
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -107,7 +107,7 @@ GL 4.0, GLSL 4.00:
   - Geometry shader instancing                         DONE (r600, radeonsi, llvmpipe, softpipe)
   - Geometry shader multiple streams                   DONE ()
   - Enhanced per-sample shading                        DONE (r600, radeonsi)
-  - Interpolation functions                            DONE (r600)
+  - Interpolation functions                            DONE (r600, radeonsi)
   - New overload resolution rules                      DONE
   GL_ARB_gpu_shader_fp64                               DONE (nvc0, radeonsi, llvmpipe, softpipe)
   GL_ARB_sample_shading                                DONE (i965, nv50, nvc0, r600, radeonsi)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 27b3c72..fa31f73 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2960,6 +2960,234 @@ static void si_llvm_emit_ddxy(
        emit_data->output[0] = lp_build_gather_values(gallivm, result, 4);
 }
 
+/*
+ * this takes an I,J coordinate pair,
+ * and works out the X and Y derivatives.
+ * it returns DDX(I), DDX(J), DDY(I), DDY(J).
+ */
+static LLVMValueRef si_llvm_emit_ddxy_interp(
+       struct lp_build_tgsi_context *bld_base,
+       LLVMValueRef interp_ij)
+{
+       struct si_shader_context *si_shader_ctx = si_shader_context(bld_base);
+       struct gallivm_state *gallivm = bld_base->base.gallivm;
+       struct lp_build_context *base = &bld_base->base;
+       LLVMValueRef indices[2];
+       LLVMValueRef store_ptr, load_ptr_x, load_ptr_y, load_ptr_ddx, load_ptr_ddy, temp, temp2;
+       LLVMValueRef tl, tr, bl, result[4];
+       LLVMTypeRef i32;
+       unsigned c;
+
+       i32 = LLVMInt32TypeInContext(gallivm->context);
+
+       indices[0] = bld_base->uint_bld.zero;
+       indices[1] = build_intrinsic(gallivm->builder, "llvm.SI.tid", i32,
+                                    NULL, 0, LLVMReadNoneAttribute);
+       store_ptr = LLVMBuildGEP(gallivm->builder, si_shader_ctx->lds,
+                                indices, 2, "");
+
+       temp = LLVMBuildAnd(gallivm->builder, indices[1],
+                           lp_build_const_int32(gallivm, TID_MASK_LEFT), "");
+
+       temp2 = LLVMBuildAnd(gallivm->builder, indices[1],
+                            lp_build_const_int32(gallivm, TID_MASK_TOP), "");
+
+       indices[1] = temp;
+       load_ptr_x = LLVMBuildGEP(gallivm->builder, si_shader_ctx->lds,
+                                 indices, 2, "");
+
+       indices[1] = temp2;
+       load_ptr_y = LLVMBuildGEP(gallivm->builder, si_shader_ctx->lds,
+                                 indices, 2, "");
+
+       indices[1] = LLVMBuildAdd(gallivm->builder, temp,
+                                 lp_build_const_int32(gallivm, 1), "");
+       load_ptr_ddx = LLVMBuildGEP(gallivm->builder, si_shader_ctx->lds,
+                                  indices, 2, "");
+
+       indices[1] = LLVMBuildAdd(gallivm->builder, temp2,
+                                 lp_build_const_int32(gallivm, 2), "");
+       load_ptr_ddy = LLVMBuildGEP(gallivm->builder, si_shader_ctx->lds,
+                                  indices, 2, "");
+
+       for (c = 0; c < 2; ++c) {
+               LLVMValueRef store_val;
+               LLVMValueRef c_ll = lp_build_const_int32(gallivm, c);
+
+               store_val = LLVMBuildExtractElement(gallivm->builder,
+                                                   interp_ij, c_ll, "");
+               LLVMBuildStore(gallivm->builder,
+                              store_val,
+                              store_ptr);
+
+               tl = LLVMBuildLoad(gallivm->builder, load_ptr_x, "");
+               tl = LLVMBuildBitCast(gallivm->builder, tl, base->elem_type, "");
+
+               tr = LLVMBuildLoad(gallivm->builder, load_ptr_ddx, "");
+               tr = LLVMBuildBitCast(gallivm->builder, tr, base->elem_type, "");
+
+               result[c] = LLVMBuildFSub(gallivm->builder, tr, tl, "");
+
+               tl = LLVMBuildLoad(gallivm->builder, load_ptr_y, "");
+               tl = LLVMBuildBitCast(gallivm->builder, tl, base->elem_type, "");
+
+               bl = LLVMBuildLoad(gallivm->builder, load_ptr_ddy, "");
+               bl = LLVMBuildBitCast(gallivm->builder, bl, base->elem_type, "");
+
+               result[c + 2] = LLVMBuildFSub(gallivm->builder, bl, tl, "");
+       }
+
+       return lp_build_gather_values(gallivm, result, 4);
+}
+
+static void interp_fetch_args(
+       struct lp_build_tgsi_context *bld_base,
+       struct lp_build_emit_data *emit_data)
+{
+       struct si_shader_context *si_shader_ctx = si_shader_context(bld_base);
+       struct gallivm_state *gallivm = bld_base->base.gallivm;
+       const struct tgsi_full_instruction *inst = emit_data->inst;
+
+       if (inst->Instruction.Opcode == TGSI_OPCODE_INTERP_OFFSET) {
+               /* offset is in second src, first two channels */
+               emit_data->args[0] = lp_build_emit_fetch(bld_base,
+                                                        emit_data->inst, 1,
+                                                        0);
+               emit_data->args[1] = lp_build_emit_fetch(bld_base,
+                                                        emit_data->inst, 1,
+                                                        1);
+               emit_data->arg_count = 2;
+       } else if (inst->Instruction.Opcode == TGSI_OPCODE_INTERP_SAMPLE) {
+               LLVMValueRef sample_position;
+               LLVMValueRef sample_id;
+               LLVMValueRef halfval = lp_build_const_float(gallivm, 0.5f);
+
+               /* fetch sample ID, then fetch its sample position,
+                * and place into first two channels.
+                */
+               sample_id = lp_build_emit_fetch(bld_base,
+                                               emit_data->inst, 1, 0);
+               sample_id = LLVMBuildBitCast(gallivm->builder, sample_id,
+                                            LLVMInt32TypeInContext(gallivm->context),
+                                            "");
+               sample_position = load_sample_position(&si_shader_ctx->radeon_bld, sample_id);
+
+               emit_data->args[0] = LLVMBuildExtractElement(gallivm->builder,
+                                                            sample_position,
+                                                            lp_build_const_int32(gallivm, 0), "");
+
+               emit_data->args[0] = LLVMBuildFSub(gallivm->builder, emit_data->args[0], halfval, "");
+               emit_data->args[1] = LLVMBuildExtractElement(gallivm->builder,
+                                                            sample_position,
+                                                            lp_build_const_int32(gallivm, 1), "");
+               emit_data->args[1] = LLVMBuildFSub(gallivm->builder, emit_data->args[1], halfval, "");
+               emit_data->arg_count = 2;
+       }
+}
+
+static void build_interp_intrinsic(const struct lp_build_tgsi_action *action,
+                               struct lp_build_tgsi_context *bld_base,
+                               struct lp_build_emit_data *emit_data)
+{
+       struct si_shader_context *si_shader_ctx = si_shader_context(bld_base);
+       struct si_shader *shader = si_shader_ctx->shader;
+       struct gallivm_state *gallivm = bld_base->base.gallivm;
+       LLVMValueRef interp_param;
+       const struct tgsi_full_instruction *inst = emit_data->inst;
+       const char *intr_name;
+       int input_index;
+       int chan;
+       int i;
+       LLVMValueRef attr_number;
+       LLVMTypeRef input_type = LLVMFloatTypeInContext(gallivm->context);
+       LLVMValueRef params = LLVMGetParam(si_shader_ctx->radeon_bld.main_fn, SI_PARAM_PRIM_MASK);
+       int interp_param_idx;
+       unsigned location;
+
+       assert(inst->Src[0].Register.File == TGSI_FILE_INPUT);
+       input_index = inst->Src[0].Register.Index;
+
+       if (inst->Instruction.Opcode == TGSI_OPCODE_INTERP_OFFSET ||
+           inst->Instruction.Opcode == TGSI_OPCODE_INTERP_SAMPLE)
+               location = TGSI_INTERPOLATE_LOC_CENTER;
+       else
+               location = TGSI_INTERPOLATE_LOC_CENTROID;
+
+       interp_param_idx = lookup_interp_param_index(shader->ps_input_interpolate[input_index],
+                                                    location);
+       if (interp_param_idx == -1)
+               return;
+       else if (interp_param_idx)
+               interp_param = LLVMGetParam(si_shader_ctx->radeon_bld.main_fn, interp_param_idx);
+       else
+               interp_param = NULL;
+
+       attr_number = lp_build_const_int32(gallivm,
+                                          shader->ps_input_param_offset[input_index]);
+
+       if (inst->Instruction.Opcode == TGSI_OPCODE_INTERP_OFFSET ||
+           inst->Instruction.Opcode == TGSI_OPCODE_INTERP_SAMPLE) {
+               LLVMValueRef ij_out[2];
+               LLVMValueRef ddxy_out = si_llvm_emit_ddxy_interp(bld_base, interp_param);
+
+               /*
+                * take the I then J parameters, and the DDX/Y for it, and
+                * calculate the IJ inputs for the interpolator.
+                * temp1 = ddx * offset/sample.x + I;
+                * interp_param.I = ddy * offset/sample.y + temp1;
+                * temp1 = ddx * offset/sample.x + J;
+                * interp_param.J = ddy * offset/sample.y + temp1;
+                */
+               for (i = 0; i < 2; i++) {
+                       LLVMValueRef ix_ll = lp_build_const_int32(gallivm, i);
+                       LLVMValueRef iy_ll = lp_build_const_int32(gallivm, i + 2);
+                       LLVMValueRef ddx_el = LLVMBuildExtractElement(gallivm->builder,
+                                                                     ddxy_out, ix_ll, "");
+                       LLVMValueRef ddy_el = LLVMBuildExtractElement(gallivm->builder,
+                                                                     ddxy_out, iy_ll, "");
+                       LLVMValueRef interp_el = LLVMBuildExtractElement(gallivm->builder,
+                                                                        interp_param, ix_ll, "");
+                       LLVMValueRef temp1, temp2;
+
+                       interp_el = LLVMBuildBitCast(gallivm->builder, interp_el,
+                                                    LLVMFloatTypeInContext(gallivm->context), "");
+
+                       temp1 = LLVMBuildFMul(gallivm->builder, ddx_el, emit_data->args[0], "");
+
+                       temp1 = LLVMBuildFAdd(gallivm->builder, temp1, interp_el, "");
+
+                       temp2 = LLVMBuildFMul(gallivm->builder, ddy_el, emit_data->args[1], "");
+
+                       temp2 = LLVMBuildFAdd(gallivm->builder, temp2, temp1, "");
+
+                       ij_out[i] = LLVMBuildBitCast(gallivm->builder,
+                                                    temp2,
+                                                    LLVMIntTypeInContext(gallivm->context, 32), "");
+               }
+               interp_param = lp_build_gather_values(bld_base->base.gallivm, ij_out, 2);
+       }
+
+       intr_name = interp_param ? "llvm.SI.fs.interp" : "llvm.SI.fs.constant";
+       for (chan = 0; chan < 2; chan++) {
+               LLVMValueRef args[4];
+               LLVMValueRef llvm_chan;
+               unsigned schan;
+
+               schan = tgsi_util_get_full_src_register_swizzle(&inst->Src[0], chan);
+               llvm_chan = lp_build_const_int32(gallivm, schan);
+
+               args[0] = llvm_chan;
+               args[1] = attr_number;
+               args[2] = params;
+               args[3] = interp_param;
+
+               emit_data->output[chan] =
+                       build_intrinsic(gallivm->builder, intr_name,
+                                       input_type, args, args[3] ? 4 : 3,
+                                       LLVMReadNoneAttribute | LLVMNoUnwindAttribute);
+       }
+}
+
 /* Emit one vertex from the geometry shader */
 static void si_llvm_emit_vertex(
        const struct lp_build_tgsi_action *action,
@@ -3073,6 +3301,11 @@ static const struct lp_build_tgsi_action txq_action = {
        .intr_name = "llvm.SI.resinfo"
 };
 
+static const struct lp_build_tgsi_action interp_action = {
+       .fetch_args = interp_fetch_args,
+       .emit = build_interp_intrinsic,
+};
+
 static void create_meta_data(struct si_shader_context *si_shader_ctx)
 {
        struct gallivm_state *gallivm = si_shader_ctx->radeon_bld.soa.bld_base.base.gallivm;
@@ -3269,7 +3502,9 @@ static void create_function(struct si_shader_context *si_shader_ctx)
            (bld_base->info->opcode_count[TGSI_OPCODE_DDX] > 0 ||
             bld_base->info->opcode_count[TGSI_OPCODE_DDY] > 0 ||
             bld_base->info->opcode_count[TGSI_OPCODE_DDX_FINE] > 0 ||
-            bld_base->info->opcode_count[TGSI_OPCODE_DDY_FINE] > 0))
+            bld_base->info->opcode_count[TGSI_OPCODE_DDY_FINE] > 0 ||
+            bld_base->info->opcode_count[TGSI_OPCODE_INTERP_OFFSET] > 0 ||
+            bld_base->info->opcode_count[TGSI_OPCODE_INTERP_SAMPLE] > 0))
                si_shader_ctx->lds =
                        LLVMAddGlobalInAddressSpace(gallivm->module,
                                                    LLVMArrayType(i32, 64),
@@ -3747,6 +3982,10 @@ int si_shader_create(struct si_screen *sscreen, LLVMTargetMachineRef tm,
        bld_base->info = poly_stipple ? &stipple_shader_info : &sel->info;
        bld_base->emit_fetch_funcs[TGSI_FILE_CONSTANT] = fetch_constant;
 
+       bld_base->op_actions[TGSI_OPCODE_INTERP_CENTROID] = interp_action;
+       bld_base->op_actions[TGSI_OPCODE_INTERP_SAMPLE] = interp_action;
+       bld_base->op_actions[TGSI_OPCODE_INTERP_OFFSET] = interp_action;
+
        bld_base->op_actions[TGSI_OPCODE_TEX] = tex_action;
        bld_base->op_actions[TGSI_OPCODE_TEX2] = tex_action;
        bld_base->op_actions[TGSI_OPCODE_TXB] = tex_action;