From 62baf92a524a5b57eb465100a5e47c489c049f15 Mon Sep 17 00:00:00 2001
From: Darren Wihandi <65404740+fairywreath@users.noreply.github.com>
Date: Mon, 21 Apr 2025 12:46:23 -0600
Subject: Add `vk::offset` to specify member offsets for push constants (#6797)

* Add struct member offset qualifier for SPIRV

* Implement for GLSL target and add tests

* clean up

* fix formatting

* fix typo

* renamed GLSLStructOffset to VkStructOffset and added emit-spirv-via-glsl test case
---
 tests/spirv/vk-offset.slang | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 tests/spirv/vk-offset.slang

(limited to 'tests/spirv')

diff --git a/tests/spirv/vk-offset.slang b/tests/spirv/vk-offset.slang
new file mode 100644
index 000000000..64cec1b55
--- /dev/null
+++ b/tests/spirv/vk-offset.slang
@@ -0,0 +1,42 @@
+//TEST:SIMPLE(filecheck=CHECK_SPV): -target spirv -emit-spirv-directly -entry vertexMain -stage vertex
+//TEST:SIMPLE(filecheck=CHECK_SPV): -target spirv -emit-spirv-via-glsl -entry vertexMain -stage vertex
+//TEST:SIMPLE(filecheck=CHECK_GLSL): -target glsl -entry vertexMain -stage vertex
+
+struct S1
+{
+    [[vk::offset(32)]]
+    float2 a;
+
+    float3 b;
+
+    [[vk::offset(16)]]
+    float4 c;
+  }
+
+[[vk::push_constant]]
+S1 pc;
+
+struct VertexOutput
+{
+    float3 position : SV_Position;
+}
+
+// CHECK_SPV: OpDecorate [[STRUCT:%[a-zA-Z0-9_]+]] Block
+// CHECK_SPV-NEXT: OpMemberDecorate [[STRUCT]] 0 Offset 32
+// CHECK_SPV-NEXT: OpMemberDecorate [[STRUCT]] 1 Offset 48
+// CHECK_SPV-NEXT: OpMemberDecorate [[STRUCT]] 2 Offset 16
+
+// CHECK_GLSL: layout(std430) uniform
+// CHECK_GLSL-NEXT: {
+// CHECK_GLSL-NEXT: layout(offset = 32) vec2 a
+// CHECK_GLSL-NEXT: vec3 b
+// CHECK_GLSL-NEXT: layout(offset = 16) vec4 c
+
+[shader("vertex")]
+VertexOutput vertexMain()
+{
+    VertexOutput output;
+    output.position = float3(pc.a.x, pc.b.y, pc.c.z);
+    return output;
+}
+
-- 
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