[Mesa-stable] [PATCH v2] radv: fix passing clip/cull distances from VS to PS

[Samuel Pitoiset]

CTS doesn't test input clip/cull distances for the fragment
shader stage, which explains why this was totally broken. I
wrote a simple test locally that works now.

This fixes a crash with GTA V and DXVK.

Note that we are exporting unused parameters from the vertex
shader now, but this can't be optimized easily because we don't
keep the fragment shader info...

Cc: mesa-stable at lists.freedesktop.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107477
Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/vulkan/radv_nir_to_llvm.c | 30 +++++++++++++++++++++++++++++-
 src/amd/vulkan/radv_pipeline.c    | 16 ++++++++++++++++
 src/amd/vulkan/radv_shader.h      |  1 +
 src/amd/vulkan/radv_shader_info.c |  4 ++++
 4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
index 4940e3230f..d7cd8cc069 100644
--- a/src/amd/vulkan/radv_nir_to_llvm.c
+++ b/src/amd/vulkan/radv_nir_to_llvm.c
@@ -2098,9 +2098,10 @@ handle_fs_input_decl(struct radv_shader_context *ctx,
 	int idx = variable->data.location;
 	unsigned attrib_count = glsl_count_attribute_slots(variable->type, false);
 	LLVMValueRef interp = NULL;
+	uint64_t mask;
 
 	variable->data.driver_location = idx * 4;
-	ctx->input_mask |= ((1ull << attrib_count) - 1) << variable->data.location;
+	mask = ((1ull << attrib_count) - 1) << variable->data.location;
 
 	if (glsl_get_base_type(glsl_without_array(variable->type)) == GLSL_TYPE_FLOAT) {
 		unsigned interp_type;
@@ -2121,6 +2122,15 @@ handle_fs_input_decl(struct radv_shader_context *ctx,
 	for (unsigned i = 0; i < attrib_count; ++i)
 		ctx->inputs[ac_llvm_reg_index_soa(idx + i, 0)] = interp;
 
+	if (idx == VARYING_SLOT_CLIP_DIST0) {
+		/* Do not account for the number of components inside the array
+		 * of clip/cull distances because this might wrongly set other
+		 * bits like primitive ID or layer.
+		 */
+		mask = 1ull << VARYING_SLOT_CLIP_DIST0;
+	}
+
+	ctx->input_mask |= mask;
 }
 
 static void
@@ -2187,6 +2197,17 @@ handle_fs_inputs(struct radv_shader_context *ctx,
 			if (LLVMIsUndef(interp_param))
 				ctx->shader_info->fs.flat_shaded_mask |= 1u << index;
 			++index;
+		} else if (i == VARYING_SLOT_CLIP_DIST0) {
+			int length = ctx->shader_info->info.ps.num_input_clips_culls;
+
+			for (unsigned j = 0; j < length; j += 4) {
+				inputs = ctx->inputs + ac_llvm_reg_index_soa(i, j);
+
+				interp_param = *inputs;
+				interp_fs_input(ctx, index, interp_param,
+						ctx->abi.prim_mask, inputs);
+				++index;
+			}
 		} else if (i == VARYING_SLOT_POS) {
 			for(int i = 0; i < 3; ++i)
 				inputs[i] = ctx->abi.frag_pos[i];
@@ -2482,6 +2503,13 @@ handle_vs_outputs_post(struct radv_shader_context *ctx,
 		memcpy(&pos_args[target - V_008DFC_SQ_EXP_POS],
 		       &args, sizeof(args));
 
+		/* Export the clip/cull distances values to the next stage. */
+		radv_export_param(ctx, param_count, &slots[0], 0xf);
+		outinfo->vs_output_param_offset[VARYING_SLOT_CLIP_DIST0] = param_count++;
+		if (ctx->num_output_clips + ctx->num_output_culls > 4) {
+			radv_export_param(ctx, param_count, &slots[4], 0xf);
+			outinfo->vs_output_param_offset[VARYING_SLOT_CLIP_DIST1] = param_count++;
+		}
 	}
 
 	LLVMValueRef pos_values[4] = {ctx->ac.f32_0, ctx->ac.f32_0, ctx->ac.f32_0, ctx->ac.f32_1};
diff --git a/src/amd/vulkan/radv_pipeline.c b/src/amd/vulkan/radv_pipeline.c
index e63c481d1e..0303642d7e 100644
--- a/src/amd/vulkan/radv_pipeline.c
+++ b/src/amd/vulkan/radv_pipeline.c
@@ -3052,6 +3052,22 @@ radv_pipeline_generate_ps_inputs(struct radeon_cmdbuf *cs,
 		ps_offset++;
 	}
 
+	if (ps->info.info.ps.num_input_clips_culls) {
+		unsigned vs_offset;
+
+		vs_offset = outinfo->vs_output_param_offset[VARYING_SLOT_CLIP_DIST0];
+		if (vs_offset != AC_EXP_PARAM_UNDEFINED) {
+			ps_input_cntl[ps_offset] = offset_to_ps_input(vs_offset, true);
+			++ps_offset;
+		}
+
+		vs_offset = outinfo->vs_output_param_offset[VARYING_SLOT_CLIP_DIST1];
+		if (vs_offset != AC_EXP_PARAM_UNDEFINED) {
+			ps_input_cntl[ps_offset] = offset_to_ps_input(vs_offset, true);
+			++ps_offset;
+		}
+	}
+
 	for (unsigned i = 0; i < 32 && (1u << i) <= ps->info.fs.input_mask; ++i) {
 		unsigned vs_offset;
 		bool flat_shade;
diff --git a/src/amd/vulkan/radv_shader.h b/src/amd/vulkan/radv_shader.h
index 03760b689c..897e2fc5e1 100644
--- a/src/amd/vulkan/radv_shader.h
+++ b/src/amd/vulkan/radv_shader.h
@@ -174,6 +174,7 @@ struct radv_shader_info {
 		bool has_pcoord;
 		bool prim_id_input;
 		bool layer_input;
+		uint8_t num_input_clips_culls;
 	} ps;
 	struct {
 		bool uses_grid_size;
diff --git a/src/amd/vulkan/radv_shader_info.c b/src/amd/vulkan/radv_shader_info.c
index 8026cca46c..a45c847c46 100644
--- a/src/amd/vulkan/radv_shader_info.c
+++ b/src/amd/vulkan/radv_shader_info.c
@@ -341,6 +341,7 @@ static void
 gather_info_input_decl_ps(const nir_shader *nir, const nir_variable *var,
 			  struct radv_shader_info *info)
 {
+	unsigned attrib_count = glsl_count_attribute_slots(var->type, false);
 	const struct glsl_type *type = glsl_without_array(var->type);
 	int idx = var->data.location;
 
@@ -354,6 +355,9 @@ gather_info_input_decl_ps(const nir_shader *nir, const nir_variable *var,
 	case VARYING_SLOT_LAYER:
 		info->ps.layer_input = true;
 		break;
+	case VARYING_SLOT_CLIP_DIST0:
+		info->ps.num_input_clips_culls = attrib_count;
+		break;
 	default:
 		break;
 	}
-- 
2.18.0