[LLDB] Simplify CAS configuration handling

Author: adrian-prantl

lldb/include/lldb/Core/ModuleList.h

@@ -24,6 +24,10 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/RWMutex.h"
 
+// BEGIN CAS
+#include "llvm/CAS/CASConfiguration.h"
+// END CAS
+
 #include <functional>
 #include <list>
 #include <mutex>
@@ -547,7 +551,7 @@ class ModuleList {
   // START CAS
 
   struct CAS {
-    std::shared_ptr<llvm::cas::CASConfiguration> configuration;
+    llvm::cas::CASConfiguration configuration;
     std::shared_ptr<llvm::cas::ObjectStore> object_store;
     std::shared_ptr<llvm::cas::ActionCache> action_cache;
   };

lldb/source/Core/ModuleList.cpp

@@ -1290,7 +1290,7 @@ class SharedModuleList {
         to_remove.ForEach([&](auto &m) {
           auto it = m_module_configs.find(m.get());
           if (it != m_module_configs.end()) {
-            m_cas_cache.erase(it->second.get());
+            m_cas_cache.erase(it->second);
             m_module_configs.erase(it);
           }
           return IterationAction::Continue;
@@ -1314,13 +1314,10 @@ class SharedModuleList {
 public:
   /// Each module may have a CAS config associated with it.
   /// Often many modules share the same CAS.
-  llvm::DenseMap<const Module *, std::shared_ptr<llvm::cas::CASConfiguration>>
-      m_module_configs;
-
-  llvm::StringMap<std::weak_ptr<llvm::cas::CASConfiguration>> m_cas_configs;
+  llvm::DenseMap<const Module *, llvm::cas::CASConfiguration> m_module_configs;
 
   /// Each CAS config has a CAS associated with it.
-  llvm::DenseMap<const llvm::cas::CASConfiguration *,
+  llvm::DenseMap<llvm::cas::CASConfiguration,
                  std::pair<std::shared_ptr<llvm::cas::ObjectStore>,
                            std::shared_ptr<llvm::cas::ActionCache>>>
       m_cas_cache;
@@ -1357,22 +1354,19 @@ static SharedModuleList &GetSharedModuleList() {
   return GetSharedModuleListInfo().module_list;
 }
 
-static std::shared_ptr<llvm::cas::CASConfiguration>
+static llvm::cas::CASConfiguration
 GetCASConfiguration(FileSpec CandidateConfigSearchPath) {
   // Config CAS from properties.
   auto &props = ModuleList::GetGlobalModuleListProperties();
   auto path = props.GetCASOnDiskPath().GetPath();
   if (!path.empty()) {
-    auto config = std::make_shared<llvm::cas::CASConfiguration>();
-    config->CASPath = props.GetCASOnDiskPath().GetPath();
-    config->PluginPath = props.GetCASPluginPath().GetPath();
-    config->PluginOptions = props.GetCASPluginOptions();
-    return config;
+    return {props.GetCASOnDiskPath().GetPath(),
+            props.GetCASPluginPath().GetPath(), props.GetCASPluginOptions()};
   }
   auto search_config = llvm::cas::CASConfiguration::createFromSearchConfigFile(
       CandidateConfigSearchPath.GetPath());
   if (search_config)
-    return std::make_shared<llvm::cas::CASConfiguration>(search_config->second);
+    return search_config->second;
 
   return {};
 }
@@ -1679,7 +1673,7 @@ static llvm::Expected<bool> loadModuleFromCASImpl(llvm::StringRef cas_id,
 
   // Swap out the module_spec with the one loaded via CAS.
   FileSpec cas_spec;
-  cas_spec.SetDirectory(ConstString(maybe_cas->configuration->CASPath));
+  cas_spec.SetDirectory(ConstString(maybe_cas->configuration.CASPath));
   cas_spec.SetFilename(ConstString(cas_id));
   ModuleSpec loaded(cas_spec, module_spec.GetUUID(), std::move(file_buffer));
   loaded.GetArchitecture() = module_spec.GetArchitecture();
@@ -1707,7 +1701,7 @@ static llvm::Expected<bool> loadModuleFromCAS(llvm::StringRef cas_id,
   return result;
 }
 
-static std::shared_ptr<llvm::cas::CASConfiguration>
+static llvm::cas::CASConfiguration
 FindCASConfiguration(const ModuleSP &module_sp) {
   auto get_dir = [](FileSpec path) {
     path.ClearFilename();
@@ -1716,7 +1710,7 @@ FindCASConfiguration(const ModuleSP &module_sp) {
 
   // Look near the binary / dSYM.
   std::set<FileSpec> unique_paths;
-  std::shared_ptr<llvm::cas::CASConfiguration> cas_config =
+  llvm::cas::CASConfiguration cas_config =
       GetCASConfiguration(module_sp->GetFileSpec());
 
   if (!cas_config) {
@@ -1762,10 +1756,9 @@ ModuleList::GetOrCreateCAS(const ModuleSP &module_sp) {
   auto &shared_module_list = GetSharedModuleListInfo();
   std::scoped_lock<std::mutex> lock(shared_module_list.shared_lock);
   auto &module_configs = shared_module_list.module_list.m_module_configs;
-  auto &cas_configs = shared_module_list.module_list.m_cas_configs;
   auto &cas_cache = shared_module_list.module_list.m_cas_cache;
 
-  std::shared_ptr<llvm::cas::CASConfiguration> cas_config;
+  llvm::cas::CASConfiguration cas_config;
   {
     auto cached_config = module_configs.find(module_sp.get());
     if (cached_config != module_configs.end()) {
@@ -1777,15 +1770,6 @@ ModuleList::GetOrCreateCAS(const ModuleSP &module_sp) {
 
   if (!cas_config) {
     cas_config = FindCASConfiguration(module_sp);
-    if (cas_config) {
-      // Unique the configuration. This assumes that no two configs
-      // with different plugins share the same path.
-      auto it = cas_configs.find(cas_config->CASPath);
-      if (it != cas_configs.end())
-        if (auto unique_config = it->second.lock())
-          cas_config = unique_config;
-      cas_configs.insert({cas_config->CASPath, cas_config});
-    }
     // Cache the config or lack thereof.
     module_configs.insert({module_sp.get(), cas_config});
   }
@@ -1795,7 +1779,7 @@ ModuleList::GetOrCreateCAS(const ModuleSP &module_sp) {
 
   // Look in the cache.
   {
-    auto cached = cas_cache.find(cas_config.get());
+    auto cached = cas_cache.find(cas_config);
     if (cached != cas_cache.end()) {
       if (!cached->second.first)
         return llvm::createStringError(
@@ -1806,15 +1790,16 @@ ModuleList::GetOrCreateCAS(const ModuleSP &module_sp) {
   }
 
   // Create the CAS.
-  auto cas = cas_config->createDatabases();
+  auto cas = cas_config.createDatabases();
   if (!cas) {
-    cas_cache.insert({cas_config.get(), {}});
+    cas_cache.insert({cas_config, {}});
     return cas.takeError();
   }
 
   LLDB_LOG(GetLog(LLDBLog::Modules | LLDBLog::Symbols),
-           "Initialized CAS at {0}", cas_config->CASPath);
-  cas_cache.insert({cas_config.get(), {cas->first, cas->second}});
+           "Initialized CAS at {0}", cas_config.CASPath);
+  assert(cas_config);  
+  cas_cache.insert({cas_config, {cas->first, cas->second}});
   return ModuleList::CAS{cas_config, cas->first, cas->second};
 }
 

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -926,14 +926,14 @@ static void ConfigureCASStorage(const std::string &m_description,
   }
   m_ast_context->SetCASStorage(std::move(cas->object_store),
                                std::move(cas->action_cache));
-  m_ast_context->GetCASOptions().CASOpts.CASPath = cas->configuration->CASPath;
+  m_ast_context->GetCASOptions().CASOpts.CASPath = cas->configuration.CASPath;
   m_ast_context->GetCASOptions().CASOpts.PluginPath =
-      cas->configuration->PluginPath;
+      cas->configuration.PluginPath;
   m_ast_context->GetCASOptions().CASOpts.PluginOptions =
-      cas->configuration->PluginOptions;
+      cas->configuration.PluginOptions;
   LOG_PRINTF(GetLog(LLDBLog::Types),
              "Setup CAS from module list properties with cas path: %s",
-             cas->configuration->CASPath.c_str());
+             cas->configuration.CASPath.c_str());
 }
 
 SwiftASTContext::ScopedDiagnostics::ScopedDiagnostics(