radeonsi: move BCOLOR PS input locations after all other inputs

BCOLOR inputs were immediately after COLOR inputs. Thus, all following inputs
were offset by 1 if color_two_side was enabled, and not offset if it was not
enabled, which is a variation that's problematic if we want to have 1 variant
per shader and the variant doesn't care about color_two_side (that should be
handled by other bytecode attached at the beginning).

Instead, move BCOLOR inputs after all other inputs, so BCOLOR0 is at location
"num_inputs" if it's present. BCOLOR1 is next.

This also allows removing si_shader::nparam and
si_shader::ps_input_param_offset, which are useless now.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/gallium/drivers/radeonsi/si_shader.c

@@ -912,9 +912,7 @@ static void declare_input_fs(
 
 	unsigned chan;
 
-	shader->ps_input_param_offset[input_index] = shader->nparam++;
+	attr_number = lp_build_const_int32(gallivm, input_index);
-	attr_number = lp_build_const_int32(gallivm,
-					   shader->ps_input_param_offset[input_index]);
 
 	shader->ps_input_interpolate[input_index] = decl->Interp.Interpolate;
 	interp_param_idx = lookup_interp_param_index(decl->Interp.Interpolate,
@@ -938,11 +936,19 @@ static void declare_input_fs(
 
 	if (decl->Semantic.Name == TGSI_SEMANTIC_COLOR &&
 	    si_shader_ctx->shader->key.ps.color_two_side) {
+		struct tgsi_shader_info *info = &shader->selector->info;
 		LLVMValueRef args[4];
 		LLVMValueRef face, is_face_positive;
-		LLVMValueRef back_attr_number =
+		LLVMValueRef back_attr_number;
-			lp_build_const_int32(gallivm,
+
-					     shader->ps_input_param_offset[input_index] + 1);
+		/* If BCOLOR0 is used, BCOLOR1 is at offset "num_inputs + 1",
+		 * otherwise it's at offset "num_inputs".
+		 */
+		unsigned back_attr_offset = shader->selector->info.num_inputs;
+		if (decl->Semantic.Index == 1 && info->colors_read & 0xf)
+			back_attr_offset += 1;
+
+		back_attr_number = lp_build_const_int32(gallivm, back_attr_offset);
 
 		face = LLVMGetParam(main_fn, SI_PARAM_FRONT_FACE);
 
@@ -974,8 +980,6 @@ static void declare_input_fs(
 						back,
 						"");
 		}
-
-		shader->nparam++;
 	} else if (decl->Semantic.Name == TGSI_SEMANTIC_FOG) {
 		LLVMValueRef args[4];
 
@@ -3280,8 +3284,7 @@ static void build_interp_intrinsic(const struct lp_build_tgsi_action *action,
 	else
 		interp_param = NULL;
 
-	attr_number = lp_build_const_int32(gallivm,
+	attr_number = lp_build_const_int32(gallivm, input_index);
-					   shader->ps_input_param_offset[input_index]);
 
 	if (inst->Instruction.Opcode == TGSI_OPCODE_INTERP_OFFSET ||
 	    inst->Instruction.Opcode == TGSI_OPCODE_INTERP_SAMPLE) {
@@ -4337,8 +4340,6 @@ int si_shader_create(struct si_screen *sscreen, LLVMTargetMachineRef tm,
 		si_dump_streamout(&sel->so);
 	}
 
-	assert(shader->nparam == 0);
-
 	si_init_shader_ctx(&si_shader_ctx, sscreen, shader, tm,
 			   poly_stipple ? &stipple_shader_info : &sel->info);
 

src/gallium/drivers/radeonsi/si_shader.h

@@ -290,9 +290,7 @@ struct si_shader {
 	struct radeon_shader_binary	binary;
 	struct si_shader_config		config;
 
-	unsigned		nparam;
 	unsigned		vs_output_param_offset[PIPE_MAX_SHADER_OUTPUTS];
-	unsigned		ps_input_param_offset[PIPE_MAX_SHADER_INPUTS];
 	unsigned		ps_input_interpolate[PIPE_MAX_SHADER_INPUTS];
 	bool			uses_instanceid;
 	unsigned		nr_pos_exports;

src/gallium/drivers/radeonsi/si_state_shaders.c

@@ -404,6 +404,18 @@ static void si_shader_vs(struct si_shader *shader, struct si_shader *gs)
 		si_set_tesseval_regs(shader, pm4);
 }
 
+static unsigned si_get_ps_num_interp(struct si_shader *ps)
+{
+	struct tgsi_shader_info *info = &ps->selector->info;
+	unsigned num_colors = !!(info->colors_read & 0x0f) +
+			      !!(info->colors_read & 0xf0);
+	unsigned num_interp = ps->selector->info.num_inputs +
+			      (ps->key.ps.color_two_side ? num_colors : 0);
+
+	assert(num_interp <= 32);
+	return MIN2(num_interp, 32);
+}
+
 static unsigned si_get_spi_shader_col_format(struct si_shader *shader)
 {
 	unsigned value = shader->key.ps.spi_shader_col_format;
@@ -507,7 +519,7 @@ static void si_shader_ps(struct si_shader *shader)
 	has_centroid = G_0286CC_PERSP_CENTROID_ENA(shader->config.spi_ps_input_ena) ||
 		       G_0286CC_LINEAR_CENTROID_ENA(shader->config.spi_ps_input_ena);
 
-	spi_ps_in_control = S_0286D8_NUM_INTERP(shader->nparam) |
+	spi_ps_in_control = S_0286D8_NUM_INTERP(si_get_ps_num_interp(shader)) |
 			    S_0286D8_BC_OPTIMIZE_DISABLE(has_centroid);
 
 	/* Set registers. */
@@ -1129,34 +1141,44 @@ static void si_emit_spi_map(struct si_context *sctx, struct r600_atom *atom)
 	struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
 	struct si_shader *ps = sctx->ps_shader.current;
 	struct si_shader *vs = si_get_vs_state(sctx);
-	struct tgsi_shader_info *psinfo;
+	struct tgsi_shader_info *psinfo = ps ? &ps->selector->info : NULL;
-	unsigned i, num_written = 0;
+	unsigned i, num_interp, num_written = 0, bcol_interp[2];
 
-	if (!ps || !ps->nparam)
+	if (!ps || !ps->selector->info.num_inputs)
 		return;
 
-	psinfo = &ps->selector->info;
+	num_interp = si_get_ps_num_interp(ps);
-
+	assert(num_interp > 0);
-	radeon_set_context_reg_seq(cs, R_028644_SPI_PS_INPUT_CNTL_0, ps->nparam);
+	radeon_set_context_reg_seq(cs, R_028644_SPI_PS_INPUT_CNTL_0, num_interp);
 
 	for (i = 0; i < psinfo->num_inputs; i++) {
 		unsigned name = psinfo->input_semantic_name[i];
 		unsigned index = psinfo->input_semantic_index[i];
 		unsigned interpolate = psinfo->input_interpolate[i];
-		unsigned param_offset = ps->ps_input_param_offset[i];
+
-bcolor:
 		radeon_emit(cs, si_get_ps_input_cntl(sctx, vs, name, index,
 						     interpolate));
 		num_written++;
 
-		if (name == TGSI_SEMANTIC_COLOR &&
+		if (name == TGSI_SEMANTIC_COLOR) {
-		    ps->key.ps.color_two_side) {
+			assert(index < ARRAY_SIZE(bcol_interp));
-			name = TGSI_SEMANTIC_BCOLOR;
+			bcol_interp[index] = interpolate;
-			param_offset++;
-			goto bcolor;
 		}
 	}
-	assert(ps->nparam == num_written);
+
+	if (ps->key.ps.color_two_side) {
+		unsigned bcol = TGSI_SEMANTIC_BCOLOR;
+
+		for (i = 0; i < 2; i++) {
+			if (!(psinfo->colors_read & (0xf << (i * 4))))
+				continue;
+
+			radeon_emit(cs, si_get_ps_input_cntl(sctx, vs, bcol,
+							     i, bcol_interp[i]));
+			num_written++;
+		}
+	}
+	assert(num_interp == num_written);
 }
 
 static void si_emit_spi_ps_input(struct si_context *sctx, struct r600_atom *atom)