tint: Support dot4I8Packed and dot4U8Packed in sem

This patch adds the support of dot4I8Packed and dot4U8Packed in
semantics under the extension "chromium_experimental_dp4a".

Bug: tint:1497
Test: tint_unittests
Change-Id: I659172fcb8953ba13b49664c6c9ad75724ff5957
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/88962
Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>

src/tint/sem/builtin.cc

@@ -145,6 +145,16 @@ bool Builtin::HasSideEffects() const {
     return false;
 }
 
+ast::Enable::ExtensionKind Builtin::RequiredExtension() const {
+    switch (type_) {
+        case sem::BuiltinType::kDot4I8Packed:
+        case sem::BuiltinType::kDot4U8Packed:
+            return ast::Enable::ExtensionKind::kChromiumExperimentalDP4a;
+        default:
+            return ast::Enable::ExtensionKind::kNotAnExtension;
+    }
+}
+
 }  // namespace tint::sem
 
 //! @endcond

src/tint/sem/builtin.h

@@ -134,6 +134,10 @@ class Builtin final : public Castable<Builtin, CallTarget> {
     /// one of its inputs)
     bool HasSideEffects() const;
 
+    /// @returns the required extension of this builtin function. Returns
+    /// ast::Enable::ExtensionKind::kNotAnExtension if no extension is required.
+    ast::Enable::ExtensionKind RequiredExtension() const;
+
   private:
     const BuiltinType type_;
     const PipelineStageSet supported_stages_;

src/tint/sem/builtin_test.cc

@@ -56,6 +56,8 @@ INSTANTIATE_TEST_SUITE_P(
                     BuiltinData{"determinant", BuiltinType::kDeterminant},
                     BuiltinData{"distance", BuiltinType::kDistance},
                     BuiltinData{"dot", BuiltinType::kDot},
+                    BuiltinData{"dot4I8Packed", BuiltinType::kDot4I8Packed},
+                    BuiltinData{"dot4U8Packed", BuiltinType::kDot4U8Packed},
                     BuiltinData{"dpdx", BuiltinType::kDpdx},
                     BuiltinData{"dpdxCoarse", BuiltinType::kDpdxCoarse},
                     BuiltinData{"dpdxFine", BuiltinType::kDpdxFine},

src/tint/sem/builtin_type.cc

@@ -89,6 +89,12 @@ BuiltinType ParseBuiltinType(const std::string& name) {
     if (name == "dot") {
         return BuiltinType::kDot;
     }
+    if (name == "dot4I8Packed") {
+        return BuiltinType::kDot4I8Packed;
+    }
+    if (name == "dot4U8Packed") {
+        return BuiltinType::kDot4U8Packed;
+    }
     if (name == "dpdx") {
         return BuiltinType::kDpdx;
     }
@@ -391,6 +397,10 @@ const char* str(BuiltinType i) {
             return "distance";
         case BuiltinType::kDot:
             return "dot";
+        case BuiltinType::kDot4I8Packed:
+            return "dot4I8Packed";
+        case BuiltinType::kDot4U8Packed:
+            return "dot4U8Packed";
         case BuiltinType::kDpdx:
             return "dpdx";
         case BuiltinType::kDpdxCoarse:

src/tint/sem/builtin_type.h

@@ -53,6 +53,8 @@ enum class BuiltinType {
     kDeterminant,
     kDistance,
     kDot,
+    kDot4I8Packed,
+    kDot4U8Packed,
     kDpdx,
     kDpdxCoarse,
     kDpdxFine,