[dawn][native] Disallow GetBGL(maxBindGroups - 1) with resource tables.

The resource tables use one bind group slot so it doesn't make sense to
query the BGL at position maxBindGroups - 1 since it conceptually
doesn't exist.

Bug: 463925499
Change-Id: Ic2a16d43c36bdeef1e6fad8fdef6ecd57fa3827d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/280438
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

Author: Kangz

src/dawn/native/Pipeline.cpp

@@ -342,9 +342,18 @@ MaybeError PipelineBase::ValidateGetBindGroupLayout(BindGroupIndex groupIndex) {
     DAWN_TRY(GetDevice()->ValidateIsAlive());
     DAWN_TRY(GetDevice()->ValidateObject(this));
     DAWN_TRY(GetDevice()->ValidateObject(mLayout.Get()));
-    DAWN_INVALID_IF(groupIndex >= kMaxBindGroupsTyped,
-                    "Bind group layout index (%u) exceeds the maximum number of bind groups (%u).",
-                    groupIndex, kMaxBindGroups);
+
+    if (mLayout->UsesResourceTable()) {
+        DAWN_INVALID_IF(groupIndex >= kMaxBindGroupsTyped - BindGroupIndex(1),
+                        "Bind group layout index (%u) exceeds or equals the maximum number of bind "
+                        "groups (%u) - 1 (one slot reserved for the resource table).",
+                        groupIndex, kMaxBindGroups);
+    } else {
+        DAWN_INVALID_IF(groupIndex >= kMaxBindGroupsTyped,
+                        "Bind group layout index (%u) exceeds or equals the maximum number of bind "
+                        "groups (%u).",
+                        groupIndex, kMaxBindGroups);
+    }
     return {};
 }
 

src/dawn/tests/unittests/validation/ResourceTableValidationTests.cpp

@@ -350,6 +350,41 @@ TEST_F(ResourceTableValidationTest,
     }
 }
 
+// Test that GetBindGroupLayout is valid for one less BGL if resource tables are used.
+TEST_F(ResourceTableValidationTest, GetBindGroupLayoutValidForOneLessIndex) {
+    // Default behavior case: GetBGL is valid until kMaxBindGroups - 1 when no resource table is
+    // used.
+    {
+        wgpu::ComputePipelineDescriptor csDesc;
+        csDesc.layout = nullptr;
+        csDesc.compute.module = utils::CreateShaderModule(device, R"(
+            enable chromium_experimental_resource_table;
+            @compute @workgroup_size(1) fn main() {
+            }
+        )");
+        wgpu::ComputePipeline pipeline = device.CreateComputePipeline(&csDesc);
+
+        pipeline.GetBindGroupLayout(kMaxBindGroups - 1);
+        ASSERT_DEVICE_ERROR(pipeline.GetBindGroupLayout(kMaxBindGroups));
+    }
+
+    // Resource table case: GetBGL is valid until kMaxBindGroups - 2.
+    {
+        wgpu::ComputePipelineDescriptor csDesc;
+        csDesc.layout = nullptr;
+        csDesc.compute.module = utils::CreateShaderModule(device, R"(
+            enable chromium_experimental_resource_table;
+            @compute @workgroup_size(1) fn main() {
+                _ = hasResource<texture_2d<f32>>(0);
+            }
+        )");
+        wgpu::ComputePipeline pipeline = device.CreateComputePipeline(&csDesc);
+
+        pipeline.GetBindGroupLayout(kMaxBindGroups - 2);
+        ASSERT_DEVICE_ERROR(pipeline.GetBindGroupLayout(kMaxBindGroups - 1));
+    }
+}
+
 // Tests calling CommandEncoder::SetResourceTable
 TEST_F(ResourceTableValidationTest, CommandEncoder_SetResourceTable) {
     // Failure case: invalid encoder state