Add InjectValidationError to command encoder

Needed to implement bytesPerRow/rowsPerImage validation
in Blink.

Bug: dawn:566
Change-Id: I60e9ebd57e40d5043e7277cdc560cbf673bc2576
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/32582
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>

dawn.json

@@ -356,6 +356,13 @@
                     {"name": "copy size", "type": "extent 3D", "annotation": "const*"}
                 ]
             },
+            {
+                "name": "inject validation error",
+                "args": [
+                    {"name": "message", "type": "char", "annotation": "const*", "length": "strlen"}
+                ],
+                "TODO": "enga@: Make this a Dawn extension"
+            },
             {
                 "name": "insert debug marker",
                 "args": [

src/dawn_native/CommandEncoder.cpp

@@ -712,6 +712,12 @@ namespace dawn_native {
         });
     }
 
+    void CommandEncoder::InjectValidationError(const char* message) {
+        if (mEncodingContext.CheckCurrentEncoder(this)) {
+            mEncodingContext.HandleError(InternalErrorType::Validation, message);
+        }
+    }
+
     void CommandEncoder::InsertDebugMarker(const char* groupLabel) {
         mEncodingContext.TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
             InsertDebugMarkerCmd* cmd =

src/dawn_native/CommandEncoder.h

@@ -61,6 +61,7 @@ namespace dawn_native {
                                   const TextureCopyView* destination,
                                   const Extent3D* copySize);
 
+        void InjectValidationError(const char* message);
         void InsertDebugMarker(const char* groupLabel);
         void PopDebugGroup();
         void PushDebugGroup(const char* groupLabel);

src/dawn_native/EncodingContext.cpp

@@ -55,6 +55,8 @@ namespace dawn_native {
 
     void EncodingContext::HandleError(InternalErrorType type, const char* message) {
         if (!IsFinished()) {
+            // Encoding should only generate validation errors.
+            ASSERT(type == InternalErrorType::Validation);
             // If the encoding context is not finished, errors are deferred until
             // Finish() is called.
             if (!mGotError) {

src/dawn_native/EncodingContext.h

@@ -53,8 +53,7 @@ namespace dawn_native {
             return false;
         }
 
-        template <typename EncodeFunction>
-        inline bool TryEncode(const ObjectBase* encoder, EncodeFunction&& encodeFunction) {
+        inline bool CheckCurrentEncoder(const ObjectBase* encoder) {
             if (DAWN_UNLIKELY(encoder != mCurrentEncoder)) {
                 if (mCurrentEncoder != mTopLevelEncoder) {
                     // The top level encoder was used when a pass encoder was current.
@@ -66,6 +65,14 @@ namespace dawn_native {
                 }
                 return false;
             }
+            return true;
+        }
+
+        template <typename EncodeFunction>
+        inline bool TryEncode(const ObjectBase* encoder, EncodeFunction&& encodeFunction) {
+            if (!CheckCurrentEncoder(encoder)) {
+                return false;
+            }
             ASSERT(!mWasMovedToIterator);
             return !ConsumedError(encodeFunction(&mAllocator));
         }

src/tests/unittests/validation/CommandBufferValidationTests.cpp

@@ -180,3 +180,10 @@ TEST_F(CommandBufferValidationTest, CallsAfterAFailedFinish) {
 
     ASSERT_DEVICE_ERROR(encoder.CopyBufferToBuffer(copyBuffer, 0, copyBuffer, 0, 0));
 }
+
+// Test that calling inject validation error produces an error.
+TEST_F(CommandBufferValidationTest, InjectValidationError) {
+    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+    encoder.InjectValidationError("my error");
+    ASSERT_DEVICE_ERROR(encoder.Finish());
+}