Add RHI Device Caching and Test Prefix Exclusion (#8448)

# Add RHI Device Caching and Test Prefix Exclusion

## Summary

This PR introduces two key improvements to the Slang test
infrastructure:

1. **RHI Device Caching**: Implements device caching to significantly
speed up test execution by reusing graphics devices across tests, **RHI
Device Caching reduces slang-test execution time from ~15 minutes to ~5
minutes in Windows release builds**
2. **Test Prefix Exclusion**: Adds `-exclude-prefix` option to skip
tests matching specified path prefixes

## Changes

### RHI Device Caching
- **New `DeviceCache` class** (`slang-test-device-cache.h/cpp`):
Thread-safe device cache with LRU eviction (max 10 devices)
- **Cache control option**: `-cache-rhi-device` flag in both
`slang-test` and `render-test`
- Default: **enabled** in slang-test, **disabled** in render-test when
run standalone
  - Automatically skips caching for CUDA devices (due to driver issues)
- **Performance benefit**: Eliminates expensive device
creation/destruction cycles, especially beneficial for Vulkan on Tegra
platforms

### Test Prefix Exclusion
- **New `-exclude-prefix <prefix>` option** in slang-test
- Allows excluding entire test directories or patterns from execution
- Complements existing `-category` and individual test filtering options

### Usage Examples
```bash
# Enable device caching (default)
slang-test

# Disable device caching
slang-test -cache-rhi-device false

# Exclude tests from specific directories
slang-test -exclude-prefix tests/problematic/
slang-test -exclude-prefix tests/slow/ -exclude-prefix tests/experimental/
```

This change should significantly improve test execution performance,
particularly in CI environments with frequent device operations. This is
needed for running the GPU test in aarch64, where repeated device
creation/destroy is causing driver issues.

Needed by: https://github.com/shader-slang/slang/issues/8346

---------

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

1 files changed, 13 insertions, 0 deletions

diff --git a/tools/slang-test/test-context.cpp b/tools/slang-test/test-context.cpp
index ede12d0d7..e3655e61d 100644
--- a/tools/slang-test/test-context.cpp
+++ b/tools/slang-test/test-context.cpp
@@ -130,6 +130,8 @@ TestContext::InnerMainFunc TestContext::getInnerMainFunc(const String& dirPath,
             loader->loadPlatformSharedLibrary(path.begin(), tool.m_sharedLibrary.writeRef())))
     {
         tool.m_func = (InnerMainFunc)tool.m_sharedLibrary->findFuncByName("innerMain");
+        tool.m_cleanDeviceCacheFunc =
+            (CleanDeviceCacheFunc)tool.m_sharedLibrary->findFuncByName("cleanDeviceCache");
     }
 
     m_sharedLibTools.add(name, tool);
@@ -152,6 +154,17 @@ void TestContext::setInnerMainFunc(const String& name, InnerMainFunc func)
     }
 }
 
+TestContext::CleanDeviceCacheFunc TestContext::getCleanDeviceCacheFunc(const String& name)
+{
+    SharedLibraryTool* tool = m_sharedLibTools.tryGetValue(name);
+    if (tool)
+    {
+        return tool->m_cleanDeviceCacheFunc;
+    }
+
+    return nullptr;
+}
+
 DownstreamCompilerSet* TestContext::getCompilerSet()
 {
     std::lock_guard<std::mutex> lock(mutex);