[PATCH 1/1] vkd3d-shader/hlsl: Initialize static variables to 0 by default.

[Francisco Casas]

From: Francisco Casas

We are currently not initializing static values to zero by default.

Consider the following shader:
```hlsl
static float4 va;

float4 main() : sv_target
{
  return va;
}
```
we get the following output:
```
ps_5_0
dcl_output o0.xyzw
dcl_temps 2
mov r0.xyzw, r1.xyzw
mov o0.xyzw, r0.xyzw
ret
```
where r1.xyzw is not initialized.

This patch solves this by assigning the static variable the value of an
uint 0, and thus, relying on complex broadcasts.

This seems to be the behaviour of the the native compiler, since it retrieves
the following error on a shader that lacks an initializer on a data type with
object components:

```
error X3017: cannot convert from 'uint' to 'struct <unnamed>'
```
---
 libs/vkd3d-shader/hlsl.y       | 35 ++++++++++++++++++++++++++++++++++
 tests/hlsl-invalid.shader_test |  8 ++++++++
 2 files changed, 43 insertions(+)

diff --git a/libs/vkd3d-shader/hlsl.y b/libs/vkd3d-shader/hlsl.y
index eedc85bd..a10f7308 100644
--- a/libs/vkd3d-shader/hlsl.y
+++ b/libs/vkd3d-shader/hlsl.y
@@ -2167,6 +2167,41 @@ static struct list *declare_vars(struct hlsl_ctx *ctx, struct hlsl_type *basic_t
             vkd3d_free(v->initializer.args);
             vkd3d_free(v->initializer.instrs);
         }
+        else if (var->modifiers & HLSL_STORAGE_STATIC)
+        {
+            struct hlsl_ir_constant *zero;
+            struct hlsl_ir_load *load;
+
+            /* Initialize statics to zero by default. */
+
+            if (type_has_object_components(var->data_type, false))
+            {
+                hlsl_error(ctx, &v->loc, VKD3D_SHADER_ERROR_HLSL_MISSING_INITIALIZER,
+                        "Static variable cannot be initialized to 0 if it has object components.");
+                vkd3d_free(v);
+                continue;
+            }
+
+            if (!(zero = hlsl_new_uint_constant(ctx, 0, &var->loc)))
+            {
+                vkd3d_free(v);
+                continue;
+            }
+            list_add_tail(&ctx->static_initializers, &zero->node.entry);
+
+            if (!(load = hlsl_new_var_load(ctx, var, var->loc)))
+            {
+                vkd3d_free(v);
+                continue;
+            }
+            list_add_tail(&ctx->static_initializers, &load->node.entry);
+
+            if (!add_assignment(ctx, &ctx->static_initializers, &load->node, ASSIGN_OP_ASSIGN, &zero->node))
+            {
+                vkd3d_free(v);
+                continue;
+            }
+        }
         vkd3d_free(v);
     }
     vkd3d_free(var_list);
diff --git a/tests/hlsl-invalid.shader_test b/tests/hlsl-invalid.shader_test
index 1b39d7f0..3e18961b 100644
--- a/tests/hlsl-invalid.shader_test
+++ b/tests/hlsl-invalid.shader_test
@@ -264,3 +264,11 @@ float4 main() : sv_target
 {
     return 1.0;
 }
+
+[pixel shader fail]
+static uint i;
+float4 main() : sv_target { return 1/i; }
+
+[pixel shader fail]
+static Texture2D tex;
+float4 main() : sv_target { return 0; }