gallium/radeon: add basic code for setting shader return values

LLVMBuildInsertValue will be used on return_value.

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

src/gallium/drivers/r600/r600_llvm.c

@@ -789,7 +789,7 @@ LLVMModuleRef r600_tgsi_llvm(
 	unsigned ArgumentsCount = 0;
 	for (unsigned i = 0; i < ctx->inputs_count; i++)
 		Arguments[ArgumentsCount++] = LLVMVectorType(bld_base->base.elem_type, 4);
-	radeon_llvm_create_func(ctx, Arguments, ArgumentsCount);
+	radeon_llvm_create_func(ctx, NULL, 0, Arguments, ArgumentsCount);
 	for (unsigned i = 0; i < ctx->inputs_count; i++) {
 		LLVMValueRef P = LLVMGetParam(ctx->main_fn, i);
 		LLVMAddAttribute(P, LLVMInRegAttribute);

src/gallium/drivers/radeon/radeon_llvm.h

@@ -113,6 +113,7 @@ struct radeon_llvm_context {
 	struct tgsi_declaration_range *arrays;
 
 	LLVMValueRef main_fn;
+	LLVMTypeRef return_type;
 
 	struct gallivm_state gallivm;
 };
@@ -162,7 +163,8 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx,
                               const char *triple);
 
 void radeon_llvm_create_func(struct radeon_llvm_context * ctx,
-                             LLVMTypeRef *ParamTypes, unsigned ParamCount);
+			     LLVMTypeRef *return_types, unsigned num_return_elems,
+			     LLVMTypeRef *ParamTypes, unsigned ParamCount);
 
 void radeon_llvm_dispose(struct radeon_llvm_context * ctx);
 

src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c

@@ -1701,14 +1701,22 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx, const char *trip
 }
 
 void radeon_llvm_create_func(struct radeon_llvm_context * ctx,
+			     LLVMTypeRef *return_types, unsigned num_return_elems,
 			     LLVMTypeRef *ParamTypes, unsigned ParamCount)
 {
-	LLVMTypeRef main_fn_type;
+	LLVMTypeRef main_fn_type, ret_type;
 	LLVMBasicBlockRef main_fn_body;
 
+	if (num_return_elems)
+		ret_type = LLVMStructTypeInContext(ctx->gallivm.context,
+						   return_types,
+						   num_return_elems, true);
+	else
+		ret_type = LLVMVoidTypeInContext(ctx->gallivm.context);
+
 	/* Setup the function */
-	main_fn_type = LLVMFunctionType(LLVMVoidTypeInContext(ctx->gallivm.context),
-					ParamTypes, ParamCount, 0);
+	ctx->return_type = ret_type;
+	main_fn_type = LLVMFunctionType(ret_type, ParamTypes, ParamCount, 0);
 	ctx->main_fn = LLVMAddFunction(ctx->gallivm.module, "main", main_fn_type);
 	main_fn_body = LLVMAppendBasicBlockInContext(ctx->gallivm.context,
 			ctx->main_fn, "main_body");

src/gallium/drivers/radeonsi/si_shader.c

@@ -96,6 +96,7 @@ struct si_shader_context
 	LLVMValueRef esgs_ring;
 	LLVMValueRef gsvs_ring[4];
 	LLVMValueRef gs_next_vertex[4];
+	LLVMValueRef return_value;
 
 	LLVMTypeRef voidt;
 	LLVMTypeRef i1;
@@ -3711,8 +3712,10 @@ static void create_function(struct si_shader_context *ctx)
 	}
 
 	assert(num_params <= Elements(params));
-	radeon_llvm_create_func(&ctx->radeon_bld, params, num_params);
+	radeon_llvm_create_func(&ctx->radeon_bld, NULL, 0,
+				params, num_params);
 	radeon_llvm_shader_type(ctx->radeon_bld.main_fn, ctx->type);
+	ctx->return_value = LLVMGetUndef(ctx->radeon_bld.return_type);
 
 	for (i = 0; i <= last_sgpr; ++i) {
 		LLVMValueRef P = LLVMGetParam(ctx->radeon_bld.main_fn, i);
@@ -4241,7 +4244,7 @@ static int si_generate_gs_copy_shader(struct si_screen *sscreen,
 
 	si_llvm_export_vs(bld_base, outputs, gsinfo->num_outputs);
 
-	LLVMBuildRetVoid(bld_base->base.gallivm->builder);
+	LLVMBuildRet(gallivm->builder, ctx->return_value);
 
 	/* Dump LLVM IR before any optimization passes */
 	if (sscreen->b.debug_flags & DBG_PREOPT_IR &&
@@ -4475,7 +4478,7 @@ int si_shader_create(struct si_screen *sscreen, LLVMTargetMachineRef tm,
 		goto out;
 	}
 
-	LLVMBuildRetVoid(bld_base->base.gallivm->builder);
+	LLVMBuildRet(bld_base->base.gallivm->builder, ctx.return_value);
 	mod = bld_base->base.gallivm->module;
 
 	/* Dump LLVM IR before any optimization passes */