2 files changed, 30 insertions, 10 deletions

diff --git a/indra/llrender/llshadermgr.cpp b/indra/llrender/llshadermgr.cpp
index 4807c12226..0ec532a55b 100644
--- a/indra/llrender/llshadermgr.cpp
+++ b/indra/llrender/llshadermgr.cpp
@@ -989,16 +989,17 @@ bool LLShaderMgr::validateProgramObject(GLuint obj)
     return success;
 }
 
-void LLShaderMgr::initShaderCache(bool enabled, const LLUUID& old_cache_version, const LLUUID& current_cache_version)
+void LLShaderMgr::initShaderCache(bool enabled, const LLUUID& old_cache_version, const LLUUID& current_cache_version, bool second_instance)
 {
+    LL_PROFILE_ZONE_SCOPED;
     LL_INFOS() << "Initializing shader cache" << LL_ENDL;
 
     mShaderCacheEnabled = gGLManager.mGLVersion >= 4.09 && enabled;
 
-    if(!mShaderCacheEnabled || mShaderCacheInitialized)
+    if(!mShaderCacheEnabled || mShaderCacheVersion.notNull())
         return;
 
-    mShaderCacheInitialized = true;
+    mShaderCacheVersion = current_cache_version;
 
     mShaderCacheDir = gDirUtilp->getExpandedFilename(LL_PATH_CACHE, "shader_cache");
     LLFile::mkdir(mShaderCacheDir);
@@ -1007,16 +1008,19 @@ void LLShaderMgr::initShaderCache(bool enabled, const LLUUID& old_cache_version,
         std::string meta_out_path = gDirUtilp->add(mShaderCacheDir, "shaderdata.llsd");
         if (gDirUtilp->fileExists(meta_out_path))
         {
+            LL_PROFILE_ZONE_NAMED("shader_cache");
             LL_INFOS() << "Loading shader cache metadata" << LL_ENDL;
 
             llifstream instream(meta_out_path);
             LLSD in_data;
+            // todo: this is likely very expensive to parse, should use binary
             LLSDSerialize::fromNotation(in_data, instream, LLSDSerialize::SIZE_UNLIMITED);
             instream.close();
 
-            if (old_cache_version == current_cache_version)
+            if (old_cache_version == current_cache_version
+                && in_data["version"].asUUID() == current_cache_version)
             {
-                for (const auto& data_pair : llsd::inMap(in_data))
+                for (const auto& data_pair : llsd::inMap(in_data["shaders"]))
                 {
                     ProgramBinaryData binary_info = ProgramBinaryData();
                     binary_info.mBinaryFormat = data_pair.second["binary_format"].asInteger();
@@ -1025,11 +1029,15 @@ void LLShaderMgr::initShaderCache(bool enabled, const LLUUID& old_cache_version,
                     mShaderBinaryCache.insert_or_assign(LLUUID(data_pair.first), binary_info);
                 }
             }
-            else
+            else if (!second_instance)
             {
                 LL_INFOS() << "Shader cache version mismatch detected. Purging." << LL_ENDL;
                 clearShaderCache();
             }
+            else
+            {
+                LL_INFOS() << "Shader cache version mismatch detected." << LL_ENDL;
+            }
         }
     }
 }
@@ -1046,10 +1054,22 @@ void LLShaderMgr::clearShaderCache()
 void LLShaderMgr::persistShaderCacheMetadata()
 {
     if(!mShaderCacheEnabled) return;
+    if (mShaderCacheVersion.isNull())
+    {
+        LL_WARNS() << "Attempted to save shader cache with no version set" << LL_ENDL;
+        return;
+    }
 
     LL_INFOS() << "Persisting shader cache metadata to disk" << LL_ENDL;
 
-    LLSD out = LLSD::emptyMap();
+    LLSD out;
+    // Settings and shader cache get saved at different time, thus making
+    // RenderShaderCacheVersion unreliable when running multiple viewer
+    // instances, or for cases where viewer crashes before saving settings.
+    // Dupplicate version to the cache itself.
+    out["version"] = mShaderCacheVersion;
+    out["shaders"] = LLSD::emptyMap();
+    LLSD &shaders = out["shaders"];
 
     static const F32 LRU_TIME = (60.f * 60.f) * 24.f * 7.f; // 14 days
     const F32 current_time = (F32)LLTimer::getTotalSeconds();
@@ -1068,7 +1088,7 @@ void LLShaderMgr::persistShaderCacheMetadata()
             data["binary_format"] = LLSD::Integer(shader_metadata.mBinaryFormat);
             data["binary_size"] = LLSD::Integer(shader_metadata.mBinaryLength);
             data["last_used"] = LLSD::Real(shader_metadata.mLastUsedTime);
-            out[it->first.asString()] = data;
+            shaders[it->first.asString()] = data;
             ++it;
         }
     }
diff --git a/indra/llrender/llshadermgr.h b/indra/llrender/llshadermgr.h
index 46788841a5..1b638e6e06 100644
--- a/indra/llrender/llshadermgr.h
+++ b/indra/llrender/llshadermgr.h
@@ -363,7 +363,7 @@ public:
     // Implemented in the application to actually update out of date uniforms for a particular shader
     virtual void updateShaderUniforms(LLGLSLShader * shader) = 0; // Pure Virtual
 
-    void initShaderCache(bool enabled, const LLUUID& old_cache_version, const LLUUID& current_cache_version);
+    void initShaderCache(bool enabled, const LLUUID& old_cache_version, const LLUUID& current_cache_version, bool second_instance);
     void clearShaderCache();
     void persistShaderCacheMetadata();
 
@@ -387,7 +387,7 @@ public:
         F32 mLastUsedTime = 0.0;
     };
     std::map<LLUUID, ProgramBinaryData> mShaderBinaryCache;
-    bool mShaderCacheInitialized = false;
+    LLUUID mShaderCacheVersion;
     bool mShaderCacheEnabled = false;
     std::string mShaderCacheDir;