Make fence descriptor optional

Bug: dawn:22
Change-Id: I5d14aa8e12899eb577d7c50081a6ee6f7ec248a0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/21365
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>

dawn.json

@@ -909,7 +909,7 @@
                 "name": "create fence",
                 "returns": "fence",
                 "args": [
-                    {"name": "descriptor", "type": "fence descriptor", "annotation": "const*"}
+                    {"name": "descriptor", "type": "fence descriptor", "annotation": "const*", "optional": true}
                 ]
             }
         ]

src/dawn_native/Queue.cpp

@@ -84,6 +84,10 @@ namespace dawn_native {
             return Fence::MakeError(GetDevice());
         }
 
+        if (descriptor == nullptr) {
+            FenceDescriptor defaultDescriptor = {};
+            return new Fence(this, &defaultDescriptor);
+        }
         return new Fence(this, descriptor);
     }
 
@@ -135,7 +139,9 @@ namespace dawn_native {
     MaybeError QueueBase::ValidateCreateFence(const FenceDescriptor* descriptor) {
         DAWN_TRY(GetDevice()->ValidateIsAlive());
         DAWN_TRY(GetDevice()->ValidateObject(this));
-        DAWN_TRY(ValidateFenceDescriptor(descriptor));
+        if (descriptor != nullptr) {
+            DAWN_TRY(ValidateFenceDescriptor(descriptor));
+        }
 
         return {};
     }

src/dawn_wire/client/ApiProcs.cpp

@@ -331,8 +331,10 @@ namespace dawn_wire { namespace client {
 
         Fence* fence = reinterpret_cast<Fence*>(cFence);
         fence->queue = queue;
-        fence->signaledValue = descriptor->initialValue;
-        fence->completedValue = descriptor->initialValue;
+
+        uint64_t initialValue = descriptor != nullptr ? descriptor->initialValue : 0u;
+        fence->signaledValue = initialValue;
+        fence->completedValue = initialValue;
         return cFence;
     }
 

src/tests/end2end/FenceTests.cpp

@@ -97,9 +97,7 @@ TEST_P(FenceTests, SimpleSignal) {
 
 // Test callbacks are called in increasing order of fence completion value
 TEST_P(FenceTests, OnCompletionOrdering) {
-    wgpu::FenceDescriptor descriptor;
-    descriptor.initialValue = 0u;
-    wgpu::Fence fence = queue.CreateFence(&descriptor);
+    wgpu::Fence fence = queue.CreateFence();
 
     queue.Signal(fence, 4);
 
@@ -133,9 +131,7 @@ TEST_P(FenceTests, OnCompletionOrdering) {
 
 // Test callbacks still occur if Queue::Signal happens multiple times
 TEST_P(FenceTests, MultipleSignalOnCompletion) {
-    wgpu::FenceDescriptor descriptor;
-    descriptor.initialValue = 0u;
-    wgpu::Fence fence = queue.CreateFence(&descriptor);
+    wgpu::Fence fence = queue.CreateFence();
 
     queue.Signal(fence, 2);
     queue.Signal(fence, 4);
@@ -149,9 +145,7 @@ TEST_P(FenceTests, MultipleSignalOnCompletion) {
 
 // Test all callbacks are called if they are added for the same fence value
 TEST_P(FenceTests, OnCompletionMultipleCallbacks) {
-    wgpu::FenceDescriptor descriptor;
-    descriptor.initialValue = 0u;
-    wgpu::Fence fence = queue.CreateFence(&descriptor);
+    wgpu::Fence fence = queue.CreateFence();
 
     queue.Signal(fence, 4);
 
@@ -178,15 +172,11 @@ TEST_P(FenceTests, OnCompletionMultipleCallbacks) {
 // TODO(enga): Enable when fence is removed from fence signal tracker
 // Currently it holds a reference and is not destructed
 TEST_P(FenceTests, DISABLED_DestroyBeforeOnCompletionEnd) {
-    wgpu::FenceDescriptor descriptor;
-    descriptor.initialValue = 0u;
-    wgpu::Fence fence = queue.CreateFence(&descriptor);
+    wgpu::Fence fence = queue.CreateFence();
 
     // The fence in this block will be deleted when it goes out of scope
     {
-        wgpu::FenceDescriptor descriptor;
-        descriptor.initialValue = 0u;
-        wgpu::Fence testFence = queue.CreateFence(&descriptor);
+        wgpu::Fence testFence = queue.CreateFence();
 
         queue.Signal(testFence, 4);
 
@@ -220,9 +210,7 @@ TEST_P(FenceTests, DISABLED_DestroyBeforeOnCompletionEnd) {
 // Regression test that validation errors that are tracked client-side are captured
 // in error scopes.
 TEST_P(FenceTests, ClientValidationErrorInErrorScope) {
-    wgpu::FenceDescriptor descriptor;
-    descriptor.initialValue = 0u;
-    wgpu::Fence fence = queue.CreateFence(&descriptor);
+    wgpu::Fence fence = queue.CreateFence();
 
     queue.Signal(fence, 4);
 

src/tests/unittests/validation/FenceValidationTests.cpp

@@ -78,6 +78,12 @@ TEST_F(FenceValidationTest, CreationSuccess) {
     }
 }
 
+// Creation succeeds if no descriptor is provided
+TEST_F(FenceValidationTest, DefaultDescriptor) {
+    wgpu::Fence fence = queue.CreateFence();
+    EXPECT_EQ(fence.GetCompletedValue(), 0u);
+}
+
 TEST_F(FenceValidationTest, GetCompletedValue) {
     // Starts at initial value
     {