[PATCH v2 0/1] MR212: vkd3d-shader/spirv: Always terminate main block.

[Jan Sikorski (＠jsikorski)]

I encountered a case where a game provides an empty fragment shader, one that disassembles to just:

```
ps_5_0
dcl_globalFlags refactoringAllowed
```
which gets translated to:

```
               OpCapability Shader
               OpMemoryModel Logical GLSL450
               OpEntryPoint Fragment %main "main"
               OpExecutionMode %main OriginUpperLeft
               OpName %main "main"
       %void = OpTypeVoid
          %3 = OpTypeFunction %void
       %main = OpFunction %void None %3
          %4 = OpLabel
               OpFunctionEnd
```

This patch is to detect that the OpLabel has not been terminated by a corresponding top-level return, and add it.

--
  v2: vkd3d-shader: Ensure that the OpLabel emitted vkd3d_spirv_builder_begin_main_function() gets terminated.

https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/212

[PATCH v2 1/1] vkd3d-shader: Ensure that the OpLabel emitted vkd3d_spirv_builder_begin_main_function() gets terminated.

[Jan Sikorski]

From: Jan Sikorski

---
 libs/vkd3d-shader/spirv.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libs/vkd3d-shader/spirv.c b/libs/vkd3d-shader/spirv.c
index ed24e743..9606902b 100644
--- a/libs/vkd3d-shader/spirv.c
+++ b/libs/vkd3d-shader/spirv.c
@@ -2247,6 +2247,7 @@ struct spirv_compiler
     struct vkd3d_push_constant_buffer_binding *push_constants;
     const struct vkd3d_shader_spirv_target_info *spirv_target_info;

+    bool main_block_open;
     bool after_declarations_section;
     struct shader_signature input_signature;
     struct shader_signature output_signature;
@@ -5216,6 +5217,7 @@ static void spirv_compiler_emit_initial_declarations(struct spirv_compiler *comp
     if (compiler->shader_type != VKD3D_SHADER_TYPE_HULL)
     {
         vkd3d_spirv_builder_begin_main_function(builder);
+        compiler->main_block_open = true;
     }
 }

@@ -7511,6 +7513,8 @@ static int spirv_compiler_emit_control_flow_instruction(struct spirv_compiler *c

if (cf_info)
                 cf_info->inside_block = false;
+            else
+                compiler->main_block_open = false;
             break;

case VKD3DSIH_RETP:
@@ -9471,6 +9475,9 @@ static int spirv_compiler_generate_spirv(struct spirv_compiler *compiler,
     if (result < 0)
         return result;

+    if (compiler->main_block_open)
+        vkd3d_spirv_build_op_return(builder);
+
     if (!is_in_default_phase(compiler))
         spirv_compiler_leave_shader_phase(compiler);
     else