[Mesa-dev] [PATCH 6/7] radeonsi/nir: add initial bindless image support

[Timothy Arceri]

---
 src/gallium/drivers/radeonsi/si_shader_nir.c | 41 +++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader_nir.c b/src/gallium/drivers/radeonsi/si_shader_nir.c
index c2036a1509..e3e71c6eb6 100644
--- a/src/gallium/drivers/radeonsi/si_shader_nir.c
+++ b/src/gallium/drivers/radeonsi/si_shader_nir.c
@@ -771,6 +771,21 @@ si_nir_lookup_interp_param(struct ac_shader_abi *abi,
 		LLVMGetParam(ctx->main_fn, interp_param_idx) : NULL;
 }
 
+static LLVMValueRef
+get_bindless_index(struct ac_shader_abi *abi,
+                   struct si_shader_context *ctx, LLVMValueRef index)
+{
+	LLVMValueRef offset =
+		LLVMBuildMul(ctx->ac.builder, index, LLVMConstInt(ctx->i32, 16, 0), "");
+
+	index = abi->load_ubo(abi, ctx->ac.i32_0);
+
+	LLVMValueRef ret = ac_build_buffer_load(&ctx->ac, index, 1, NULL, offset,
+						NULL, 0, false, false, true, true);
+
+	return LLVMBuildBitCast(ctx->ac.builder, ret, ctx->i32, "");
+}
+
 static LLVMValueRef
 si_nir_load_sampler_desc(struct ac_shader_abi *abi,
 		         unsigned descriptor_set, unsigned base_index,
@@ -780,8 +795,10 @@ si_nir_load_sampler_desc(struct ac_shader_abi *abi,
 {
 	struct si_shader_context *ctx = si_shader_context_from_abi(abi);
 	LLVMBuilderRef builder = ctx->ac.builder;
-	LLVMValueRef list = LLVMGetParam(ctx->main_fn, ctx->param_samplers_and_images);
 	LLVMValueRef index = dynamic_index;
+	LLVMValueRef list = bindless ?
+		LLVMGetParam(ctx->main_fn, ctx->param_bindless_samplers_and_images) :
+		LLVMGetParam(ctx->main_fn, ctx->param_samplers_and_images);
 
 	assert(!descriptor_set);
 
@@ -794,14 +811,24 @@ si_nir_load_sampler_desc(struct ac_shader_abi *abi,
 
 	if (image) {
 		assert(desc_type == AC_DESC_IMAGE || desc_type == AC_DESC_BUFFER);
-		assert(base_index + constant_index < ctx->num_images);
 
-		if (dynamic_index)
-			index = si_llvm_bound_index(ctx, index, ctx->num_images);
+		if (bindless) {
+			LLVMValueRef ret = get_bindless_index(abi, ctx, index);
 
-		index = LLVMBuildSub(ctx->gallivm.builder,
-				     LLVMConstInt(ctx->i32, SI_NUM_IMAGES - 1, 0),
-				     index, "");
+			/* For simplicity, bindless image descriptors use fixed
+			 * 16-dword slots for now.
+			 */
+			index = LLVMBuildMul(ctx->ac.builder, ret,
+					     LLVMConstInt(ctx->i32, 2, 0), "");
+		} else {
+			assert(base_index + constant_index < ctx->num_images);
+			if (dynamic_index)
+				index = si_llvm_bound_index(ctx, index, ctx->num_images);
+
+			index = LLVMBuildSub(ctx->gallivm.builder,
+					     LLVMConstInt(ctx->i32, SI_NUM_IMAGES - 1, 0),
+					     index, "");
+		}
 
 		/* TODO: be smarter about when we use dcc_off */
 		return si_load_image_desc(ctx, list, index, desc_type, write);
-- 
2.14.3