Avoid using the backend validation when using test server (#6094)

* Avoid using the backend validation when using test server

Currently with a debug build, the backend validation such
as Vulkan-Validation-Layer or DXC validation is enabled all the time.
It means there is a higher chance that we see warning messages while
running slang-test with a debug build.

However, those warning messages incorrectly treated as the testing
result when using test-server. This is mainly because of the fact that
the Slang implemention for the RPC commucation expects only one time
output result. As soon as any warning is printed, the testing process is
incorrectly considered as completed even though it might be still in the
middle of initializing the device.

This commit disables the backend validation when using the test-server.

* format code (#31)

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

---------

Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>
Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>
Co-authored-by: Yong He <yonghe@outlook.com>

tools/render-test/options.cpp

@@ -249,6 +249,10 @@ static rhi::DeviceType _toRenderType(Slang::RenderApiType apiType)
         {
             SLANG_RETURN_ON_FAIL(reader.expectArg(outOptions.entryPointName));
         }
+        else if (argValue == "-enable-backend-validation")
+        {
+            outOptions.enableBackendValidation = true;
+        }
         else
         {
             // Lookup

tools/render-test/options.h

@@ -87,6 +87,8 @@ struct Options
 
     bool generateSPIRVDirectly = true;
 
+    bool enableBackendValidation = false;
+
     Options() { downstreamArgs.addName("slang"); }
 
     static SlangResult parse(

tools/render-test/render-test-main.cpp

@@ -1367,10 +1367,12 @@ static SlangResult _innerMain(
 
 #if _DEBUG
         desc.enableValidation = true;
-        desc.enableBackendValidation = true;
         desc.debugCallback = &debugCallback;
 #endif
 
+        if (options.enableBackendValidation)
+            desc.enableBackendValidation = true;
+
         desc.slang.lineDirectiveMode = SLANG_LINE_DIRECTIVE_MODE_NONE;
         if (options.generateSPIRVDirectly)
             desc.slang.targetFlags = SLANG_TARGET_FLAG_GENERATE_SPIRV_DIRECTLY;

tools/slang-test/slang-test-main.cpp

@@ -3478,6 +3478,15 @@ TestResult runComputeComparisonImpl(
     auto actualOutputFile = outputStem + ".actual.txt";
     cmdLine.addArg(actualOutputFile);
 
+#if _DEBUG
+    // When using test server, any validation warning printed from the backend
+    // gets misinterpreted as the result from the test.
+    // This is due to the limitation that Slang RPC implementation expects only
+    // one time communication.
+    if (input.spawnType != SpawnType::UseTestServer)
+        cmdLine.addArg("-enable-backend-validation");
+#endif
+
     if (context->isExecuting())
     {
         // clear the stale actual output file first. This will allow us to detect error if