radeonsi: use an explicit symbol for the LSHS LDS memory

Reviewed-by: Marek Olšák <[email protected]>

2 files changed, 20 insertions, 2 deletions

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index a2fec104a54..3617214ebef 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -4925,8 +4925,21 @@ static void create_function(struct si_shader_context *ctx)
 	assert(shader->info.num_input_vgprs >= num_prolog_vgprs);
 	shader->info.num_input_vgprs -= num_prolog_vgprs;
 
-	if (shader->key.as_ls || ctx->type == PIPE_SHADER_TESS_CTRL)
-		ac_declare_lds_as_pointer(&ctx->ac);
+	if (shader->key.as_ls || ctx->type == PIPE_SHADER_TESS_CTRL) {
+		if (USE_LDS_SYMBOLS && HAVE_LLVM >= 0x0900) {
+			/* The LSHS size is not known until draw time, so we append it
+			 * at the end of whatever LDS use there may be in the rest of
+			 * the shader (currently none, unless LLVM decides to do its
+			 * own LDS-based lowering).
+			 */
+			ctx->ac.lds = LLVMAddGlobalInAddressSpace(
+				ctx->ac.module, LLVMArrayType(ctx->i32, 0),
+				"__lds_end", AC_ADDR_SPACE_LDS);
+			LLVMSetAlignment(ctx->ac.lds, 256);
+		} else {
+			ac_declare_lds_as_pointer(&ctx->ac);
+		}
+	}
 }
 
 /**
diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index b8a4a52a400..d780547659e 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -252,6 +252,11 @@ static void si_emit_derived_tess_state(struct si_context *sctx,
 				  C_VS_STATE_LS_OUT_VERTEX_SIZE;
 	sctx->current_vs_state |= tcs_in_layout;
 
+	/* We should be able to support in-shader LDS use with LLVM >= 9
+	 * by just adding the lds_sizes together, but it has never
+	 * been tested. */
+	assert(ls_current->config.lds_size == 0);
+
 	if (sctx->chip_class >= GFX9) {
 		unsigned hs_rsrc2 = ls_current->config.rsrc2 |
 				    S_00B42C_LDS_SIZE(lds_size);