radv/gfx10: declare an external symbol for the ESGS ring

It will be used for stream output but for now only declares it
if VS and if the PrimitiveID needs to be exported.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
index 00c7df8574b7bae536bdf937fa6529fb328b4ebc..a5551203d290fd9da47abf3e123ec127da1b236c 100644 (file)
--- a/src/amd/vulkan/radv_nir_to_llvm.c
+++ b/src/amd/vulkan/radv_nir_to_llvm.c
@@ -4229,6 +4229,25 @@ static void prepare_gs_input_vgprs(struct radv_shader_context *ctx)
        ctx->gs_wave_id = ac_unpack_param(&ctx->ac, ctx->merged_wave_info, 16, 8);
 }
 
+/* Ensure that the esgs ring is declared.
+ *
+ * We declare it with 64KB alignment as a hint that the
+ * pointer value will always be 0.
+ */
+static void declare_esgs_ring(struct radv_shader_context *ctx)
+{
+       if (ctx->esgs_ring)
+               return;
+
+       assert(!LLVMGetNamedGlobal(ctx->ac.module, "esgs_ring"));
+
+       ctx->esgs_ring = LLVMAddGlobalInAddressSpace(
+               ctx->ac.module, LLVMArrayType(ctx->ac.i32, 0),
+               "esgs_ring",
+               AC_ADDR_SPACE_LDS);
+       LLVMSetLinkage(ctx->esgs_ring, LLVMExternalLinkage);
+       LLVMSetAlignment(ctx->esgs_ring, 64 * 1024);
+}
 
 static
 LLVMModuleRef ac_translate_nir_to_llvm(struct ac_llvm_compiler *ac_llvm,
@@ -4368,6 +4387,12 @@ LLVMModuleRef ac_translate_nir_to_llvm(struct ac_llvm_compiler *ac_llvm,
                        ctx.abi.emit_kill = radv_emit_kill;
                }
 
+               if (shaders[i]->info.stage == MESA_SHADER_VERTEX &&
+                   ctx.options->key.vs_common_out.as_ngg &&
+                   ctx.options->key.vs_common_out.export_prim_id) {
+                       declare_esgs_ring(&ctx);
+               }
+
                if (i)
                        ac_emit_barrier(&ctx.ac, ctx.stage);