Making it easier to work with shaders https://git.yummers.dev/slang.git/atom?h=master 2025-07-31T21:32:02+00:00 2025-07-31T21:32:02+00:00 Jay Kwak 82421531+jkwak-work@users.noreply.github.com 2025-07-31T21:32:02+00:00 urn:sha1:aefd1e3e0dbe4e77f8d7dbbfa04e15c2db615394 * Handle debug-layer messages in a separate channel The Problem (Issue #7343) The issue was that Vulkan Validation Layer error messages were being mixed into regular test output, causing potential false positives or negatives. When using -enable-debug-layers true, validation messages would appear in the same output stream as test results, potentially matching //CHECK: patterns incorrectly. Example Problem: - Test expects: //CHECK: 1 - Validation layer prints: VALIDATION ERROR: 1 invalid buffer binding - Test incorrectly matches the "1" in the error message instead of the actual output Slang Test Communication Architecture Execution Modes Slang has 3 different execution modes controlled by SpawnType: enum class SpawnType { UseSharedLibrary, // In-process execution UseTestServer, // Out-of-process via persistent server UseFullyIsolatedTestServer, // Out-of-process via isolated server UseExe // Direct executable spawn } 1. In-Process Mode (UseSharedLibrary) ┌─────────────────────────────────────────┐ │ slang-test │ │ ┌─────────────┐ ┌─────────────────┐ │ │ │render-test │ │gfx-unit-test │ │ │ │unit-test │ │slangc library │ │ │ └─────────────┘ └─────────────────┘ │ │ │ │ │ │ └───► StdWriters ◄──┘ │ │ (shared) │ └─────────────────────────────────────────┘ - Communication: Direct function calls, shared memory - Debug callbacks: Single callback instance in StdWriters - Used when: Default mode for most tests 2. Out-of-Process Mode (UseTestServer) ┌──────────────────┐ JSON-RPC ┌──────────────────┐ │ slang-test │◄──over pipes────┤ test-server.exe │ │ │ │ │ │ ┌─────────────┐ │ │ ┌─────────────┐ │ │ │StdWriters │ │ │ │render-test │ │ │ │+debug │ │ │ │gfx-unit-test│ │ │ │callback │ │ │ │+debug │ │ │ └─────────────┘ │ │ │callback │ │ └──────────────────┘ │ └─────────────┘ │ └──────────────────┘ - Communication: JSON-RPC over stdin/stdout pipes - Debug callbacks: Separate instances in each process - Used when: CI/CD, multi-threaded testing, crash isolation 3. Direct Executable Mode (UseExe) ┌──────────────────┐ pipes ┌──────────────────┐ │ slang-test │◄───────────────┤ slangc.exe │ │ │ │ other tools │ └──────────────────┘ └──────────────────┘ - Communication: Standard process pipes (stdout/stderr) - Debug callbacks: None (external executables) - Used when: Testing external tools Communication Mechanisms Deep Dive JSON-RPC Protocol Over Pipes The test-server.exe communicates with slang-test using JSON-RPC over stdin/stdout pipes: // Parent process (slang-test) creates child with pipes Process* testServerProcess = /* spawn test-server.exe */; // JSONRPCConnection wraps the pipe communication JSONRPCConnection connection; connection.initWithStdStreams(); // Uses stdin/stdout pipes // Send RPC call TestServerProtocol::ExecutionResult result; connection.sendCall("executeTool", &args, &result); Key Point: The pipes carry structured JSON messages, not raw stdout/stderr. This is what enables clean separation of different data channels. Protocol Structure Your changes extend the ExecutionResult protocol: struct ExecutionResult { String stdOut; // Regular program output String stdError; // Error messages String debugLayer; // NEW: Debug/validation messages int32_t result; int32_t returnCode; }; Your Debug Layer Solution The Challenge Memory pointers cannot cross process boundaries. A debugCallback pointer in the parent process is meaningless in the child process. The Solution: String-Based Serialization You solved this by using string capture and serialization: 1. Debug Callback Interface (slang-std-writers.h) class IDebugCallback { virtual void handleMessage( DebugMessageType type, DebugMessageSource source, const char* message) = 0; }; 2. String-Capturing Implementation (slang-support.h) class CoreDebugCallback : public Slang::IDebugCallback { StringBuilder m_buf; // Captures messages as strings void handleMessage(DebugMessageType type, DebugMessageSource source, const char* message) { if (type == DebugMessageType::Error) { m_buf << message << '\n'; // Serialize to string } } String getString() { return m_buf.toString(); } // Extract accumulated messages }; 3. Bridge Between RHI and Core (slang-support.h) class CoreToRHIDebugBridge : public rhi::IDebugCallback { Slang::IDebugCallback* m_coreCallback; void handleMessage(rhi::DebugMessageType type, rhi::DebugMessageSource source, const char* message) { // Convert RHI types to core types and forward m_coreCallback->handleMessage(convertType(type), convertSource(source), message); } }; Data Flow: Debug Messages End-to-End In-Process Mode Flow GPU Driver → RHI Debug Callback → Core Debug Callback → String Buffer → Test Output Out-of-Process Mode Flow Child Process: GPU Driver → RHI Debug Callback → Core Debug Callback → String Buffer ↓ Parent Process: JSON-RPC Serialization Test Output ← String Processing ← ExecutionResult.debugLayer ←┘ Step-by-Step Example 1. Test Execution Starts // In test-server process CoreDebugCallback debugCallback; CoreToRHIDebugBridge bridge; bridge.setCoreCallback(&debugCallback); // Set up graphics device with debug layers deviceDesc.debugCallback = &bridge; 2. Graphics API Call Triggers Validation Error // Inside Vulkan driver (external code) // Validation layer detects error and calls our callback bridge.handleMessage(RHI_ERROR, RHI_LAYER, "Invalid buffer binding"); 3. Message Capture // In CoreDebugCallback::handleMessage m_buf << "Invalid buffer binding\n"; // Stored in string buffer 4. Test Completion & Serialization // Back in test-server TestServerProtocol::ExecutionResult result; result.debugLayer = debugCallback.getString(); // "Invalid buffer binding\n" result.stdOut = "1"; // Regular test output // Send via JSON-RPC connection.sendResult(&result); 5. Parent Process Receives & Separates Output // In slang-test process String output = buildTestOutput(result); // Results in clean separation: // standard output = { // 1 // } // debug layer = { // Invalid buffer binding // } Why This Solution Works 1. Process Isolation: Each process has its own callback objects, no shared pointers 2. String Serialization: Debug messages converted to strings that can cross process boundaries 3. Protocol Extension: Uses existing JSON-RPC infrastructure, just adds new field 4. Clean Separation: Debug messages never mix with stdout/stderr 5. Backward Compatibility: Existing tests unaffected, debug layer field optional Key Benefits - Eliminates False Positives: Debug messages can't interfere with //CHECK: patterns - Better Debugging: Debug messages clearly separated and labeled - Robust Architecture: Works across all execution modes - Minimal Changes: Leverages existing communication infrastructure This elegant solution transforms a fundamental cross-process communication challenge into a simple string serialization problem, using the existing test server architecture to cleanly separate validation layer messages from test results. * Cover the missing slang-test execution path * format code (#82) 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> 2025-06-04T09:58:33+00:00 Jay Kwak 82421531+jkwak-work@users.noreply.github.com 2025-06-04T09:58:33+00:00 urn:sha1:454792a55496dfb00c20c724f6a491bb3110f957 2024-10-29T06:49:26+00:00 Ellie Hermaszewska ellieh@nvidia.com 2024-10-29T06:49:26+00:00 urn:sha1:f65d756bff8d4c5cbc15bd0322a2ae8e6b896a21 * format * Minor test fixes * enable checking cpp format in ci 2021-11-23T21:23:15+00:00 jsmall-nvidia jsmall@nvidia.com 2021-11-23T21:23:15+00:00 urn:sha1:9e084ffab37c276d40931a58633041a2e10de623 * #include an absolute path didn't work - because paths were taken to always be relative. * Use 'Process' to communicate with an command line tool. * Remove slang-win-stream * Tidy up windows ProcessUtil. * First version of BufferedReadStream. * Windows working IPC for steams. * Test proxy count option. * Split Process/ProcessUtil. Process is platform dependant. ProcessUtil are functions that are platform independent. * First implementation of Unix Process interface. * Unix process compiles on cygwin. * Fix typo in unix process. * Separate unix pipe stream error of invalid access, from pipe availability. * Fix in standard line extraction. * Make fd non blocking. * Fix issues with Windows Process streams. * Added UnixPipe. * Some fixes around UnixPipeStream. * Make a unix stream closed explicit. * Hack to debug linux process/stream. * Revert to old linux pipe handling. * Pass executable path for unit tests. Split out CommandLine into own source. * Small improvements in process/command line. * Check process behavior with crash. * Make stderr and stdout unbuffered for crash testing. * Only turn disable buffering in crash test. * Disable crash test on CI. * Fix crash on clang/linux. * Enable crash test. Remove _appendBuffer as can use StreamUtil functionality. * Added inital processing for http headers. * Small improvements to HttpHeader. * First pass HTTPPacketConnection working on windows. * Enable other Process communication tests. * Update comments. * WIP JSON RPC. * Add terminate to Process. Made JSONRPC a Util. * Small tidy up around HTTPPacketConnection. * Improve process termination options. * WIP for test-server. * Add diagnostics error handling to test-server. * Improved JSON support. Parsing/creating JSON-RPC messages. * WIP JSONRPC parsing. * First pass RttiInfo support. * WIP converting between JSON/native types. * Project files. * Split out RttiUtil. Made RttiInfo constuction thread safe. * WIP RTTI<->JSON. * Add diagnostics to JSON<->native conversions. * Make RttiInfo for structs globals. Avoids problem around derived types (like pointers), being able to cause an abort. * Add pointer support to RTTI. Fixed some compilation issues on linux. * Add fixed array support. * Added Rtti unit test. * Add rtti unit test. * Split out quoted/unquoted key handling. Fix bugs in JSON value/container. Added JSON native test. * Make default array allocator use malloc/free. Remove the new[] handler (doesn't work on visuals studio). * Fix for linux warning. * Remove some test code. * Fix issues on x86 win. * Fix warning on aarch64. * Fix some bugs in JSON parsing/handling. Make Rtti work copy/dtor/ctor struct types. * Testing JSON<->native with fixed array. Make makeArrayView explicit if it's just a single value. Added array type. * Fix getting arrayView. * Improve JSON diagnostic name. * First pass refactor using Rtti for JSON RPC. * First pass of test server using RTTI/JSON-RPC. * Added JSONRPCConnection. * Fix some naming issues. * First pass of test-server working. * Added unit test support for JSON-RPC test server. * Fix compilation issues on linux around template handling. * Typo fix. * Fix a bug around SourceLoc lookup with JSONContainer. * Set the console type to console for ISlangWriters. * Small improvements to test-server. * Small improvements in test-server. * Small fix.