Adapter selection for Renderer (#923)

* * Make adapter used selectable on the command line
* Added 'adapter' to Renderer::Desc with dx11, dx12, vk honoring it
* GL will check that the renderer matches, but cannot select a specific device
* Share functionality on dx adapter selection in D3DUtil

Note - that on tests that use OpenGL and the adapter doesn't match it will ignore the test (and display a message that the appropriate device couldn't be started)

* Small function name improvement.

* Variable rename to match type.

* Fix typo in Dx12 device selection.

* * Add checking if an adapter is warp
* Improve some comments

1 files changed, 9 insertions, 0 deletions

diff --git a/tools/slang-test/options.cpp b/tools/slang-test/options.cpp
index 70b7a4533..2b9ec6c06 100644
--- a/tools/slang-test/options.cpp
+++ b/tools/slang-test/options.cpp
@@ -170,6 +170,15 @@ static bool _isSubCommand(const char* arg)
             argCursor++;
             // Assumed to be handle by .bat file that called us
         }
+        else if (strcmp(arg, "-adapter") == 0)
+        {
+            if (argCursor == argEnd)
+            {
+                stdError.print("error: expected operand for '%s'\n", arg);
+                return SLANG_FAIL;
+            }
+            optionsOut->adapter = *argCursor++;
+        }
         else if (strcmp(arg, "-appveyor") == 0)
         {
             optionsOut->outputMode = TestOutputMode::AppVeyor;