resolver: Limit the number of parameters to 255

See: https://github.com/gpuweb/gpuweb/issues/1959

Fixed: chromium:1228642
Change-Id: Iadedd0a1396ebb6a006caa99e0931a92eb2c008e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/58390
Commit-Queue: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>

src/resolver/function_validation_test.cc

@@ -644,6 +644,28 @@ TEST_F(ResolverFunctionValidationTest, ParameterSotreType_AtomicFree) {
   EXPECT_TRUE(r()->Resolve()) << r()->error();
 }
 
+TEST_F(ResolverFunctionValidationTest, ParametersAtLimit) {
+  ast::VariableList params;
+  for (int i = 0; i < 255; i++) {
+    params.emplace_back(Param("param_" + std::to_string(i), ty.i32()));
+  }
+  Func(Source{{12, 34}}, "f", params, ty.void_(), {});
+
+  EXPECT_TRUE(r()->Resolve()) << r()->error();
+}
+
+TEST_F(ResolverFunctionValidationTest, ParametersOverLimit) {
+  ast::VariableList params;
+  for (int i = 0; i < 256; i++) {
+    params.emplace_back(Param("param_" + std::to_string(i), ty.i32()));
+  }
+  Func(Source{{12, 34}}, "f", params, ty.void_(), {});
+
+  EXPECT_FALSE(r()->Resolve());
+  EXPECT_EQ(r()->error(),
+            "12:34 error: functions may declare at most 255 parameters");
+}
+
 struct TestParams {
   ast::StorageClass storage_class;
   bool should_pass;

src/resolver/resolver.cc

@@ -1388,6 +1388,11 @@ bool Resolver::ValidateFunction(const ast::Function* func,
     }
   }
 
+  if (func->params().size() > 255) {
+    AddError("functions may declare at most 255 parameters", func->source());
+    return false;
+  }
+
   for (auto* param : func->params()) {
     if (!ValidateFunctionParameter(func, variable_to_info_.at(param))) {
       return false;