PersistentShaderCache integration (#2453)

* Shader cache index integrated into RendererBase; Added test for cache eviction policy (which currently does not pass)

* Restructured main if block in getEntryPointCodeFromShaderCache; Post-rebase cleanup

* undo local testing only change

* Fixed issues causing shader cache tests to fail

* Edited gfx.slang to reflect structural changes to IDevice::Desc and to include ShaderCacheDesc; Modified how the cache is reading in the file from disk; Added a check to the cache eviction policy test that checks for correct order of entries in the cache as well as eight total expected output files for D3D12 and Vulkan

* Removed line in gfx-unit-test.cpp for local testing

* Edited .gitignore to ignore all shaders automatically generated by the shader cache tests and removed the test shaders that were previously added; Review changes, most notably with an overhaul of how the cache eviction policy test handles checking order of entries

* Ran premake; Removed local testing specific line (again)

* Removed expected comparison files from earlier commit; Ran premake

* Edited premake5.lua to also ignore the auto-generated shader files from specific shader cache tests

* Fixed weird indent in premake5.lua

1 files changed, 13 insertions, 11 deletions

diff --git a/tools/gfx/persistent-shader-cache.cpp b/tools/gfx/persistent-shader-cache.cpp
index a378e0f4f..55a95a257 100644
--- a/tools/gfx/persistent-shader-cache.cpp
+++ b/tools/gfx/persistent-shader-cache.cpp
@@ -6,14 +6,15 @@
 #include "../../source/core/slang-string-util.h"
 #include "../../source/core/slang-file-system.h"
 
-namespace Slang
+namespace gfx
 {
 
-PersistentShaderCache::PersistentShaderCache(const Desc& inDesc)
+PersistentShaderCache::PersistentShaderCache(const IDevice::ShaderCacheDesc& inDesc)
 {
     desc = inDesc;
 
-    if (!desc.shaderCachePath.getBuffer())
+    // If a path is provided, we will want our underlying file system to be initialized using that path.
+    if (desc.shaderCachePath)
     {
         if (!desc.shaderCacheFileSystem)
         {
@@ -25,7 +26,7 @@ PersistentShaderCache::PersistentShaderCache(const Desc& inDesc)
     }
 
     // If our shader cache has an underlying file system, check if it's mutable. If so, store a pointer
-    // to the mutable version in order to save new entries later.
+    // to the mutable version for operations which require writing to disk.
     if (desc.shaderCacheFileSystem)
     {
         desc.shaderCacheFileSystem->queryInterface(ISlangMutableFileSystem::getTypeGuid(), (void**)mutableShaderCacheFileSystem.writeRef());
@@ -39,27 +40,28 @@ PersistentShaderCache::PersistentShaderCache(const Desc& inDesc)
 void PersistentShaderCache::loadCacheFromFile()
 {
     ComPtr<ISlangBlob> indexBlob;
-    if (SLANG_FAILED(desc.shaderCacheFileSystem->loadFile(desc.cacheFilename.getBuffer(), indexBlob.writeRef())))
+    if (SLANG_FAILED(desc.shaderCacheFileSystem->loadFile(desc.cacheFilename, indexBlob.writeRef())))
     {
         // Cache index not found, so we'll create and save a new one.
         if (mutableShaderCacheFileSystem)
         {
-            mutableShaderCacheFileSystem->saveFile(desc.cacheFilename.getBuffer(), nullptr, 0);
+            mutableShaderCacheFileSystem->saveFile(desc.cacheFilename, nullptr, 0);
             return;
         }
         // Cache index not found and we can't save a new one due to the file system being immutable.
         return;
     }
 
-    String indexString;
-    File::readAllText(desc.cacheFilename, indexString);
+    auto indexString = UnownedStringSlice((char*)indexBlob->getBufferPointer());
 
     List<UnownedStringSlice> lines;
-    StringUtil::calcLines(indexString.getUnownedSlice(), lines);
+    StringUtil::calcLines(indexString, lines);
     for (auto line : lines)
     {
         List<UnownedStringSlice> digests;
-        StringUtil::split(line, ' ', digests); // This will return our two hashes as two elements in digests.
+        StringUtil::split(line, ' ', digests); // This will return our two hashes as two elements in digests, unless we've reached the end.
+        if (digests.getCount() != 2)
+            continue;
         auto dependencyDigest = DigestUtil::fromString(digests[0]);
         auto astDigest = DigestUtil::fromString(digests[1]);
 
@@ -158,7 +160,7 @@ void PersistentShaderCache::saveCacheToFile()
         indexSb << "\n";
     }
 
-    mutableShaderCacheFileSystem->saveFile(desc.cacheFilename.getBuffer(), indexSb.getBuffer(), indexSb.getLength());
+    mutableShaderCacheFileSystem->saveFile(desc.cacheFilename, indexSb.getBuffer(), indexSb.getLength());
 }
 
 void PersistentShaderCache::deleteLRUEntry()