[Lldb-commits] [PATCH] D157165: [lldb] [darwin kernel debug] When looking for a Darwin kernel symbol file, call GetSharedModules before DownloadObjectAndSymbolFile

[Jason Molenda via Phabricator via lldb-commits]

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ModuleList::GetSharedModule will call in to the DebugSymbols framework and may be able to find a file on the local system by Spotlight search, or by using the Platform's override of GetSharedModule, and may be faster than calling Symbols::DownloadObjectAndSymbolFile which calls out to an external program and is likely to do a network filesystem or download of the binary/symbol file.

A small perf improvement, NFC.  This is very much jason code, not really looking for a review of this one.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D157165

Files:
  lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp


Index: lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
+++ lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
@@ -763,20 +763,6 @@
       module_spec.GetUUID() = m_uuid;
       module_spec.GetArchitecture() = target.GetArchitecture();
 
-      // For the kernel, we really do need an on-disk file copy of the binary
-      // to do anything useful. This will force a call to dsymForUUID if it
-      // exists, instead of depending on the DebugSymbols preferences being
-      // set.
-      if (IsKernel()) {
-        Status error;
-        if (Symbols::DownloadObjectAndSymbolFile(module_spec, error, true)) {
-          if (FileSystem::Instance().Exists(module_spec.GetFileSpec())) {
-            m_module_sp = std::make_shared<Module>(module_spec.GetFileSpec(),
-                                                   target.GetArchitecture());
-          }
-        }
-      }
-
       // If the current platform is PlatformDarwinKernel, create a ModuleSpec
       // with the filename set to be the bundle ID for this kext, e.g.
       // "com.apple.filesystems.msdosfs", and ask the platform to find it.
@@ -806,6 +792,22 @@
         m_module_sp = target.GetOrCreateModule(module_spec, true /* notify */);
       }
 
+      // For the kernel, we really do need an on-disk file copy of the binary
+      // to do anything useful. This will force a call to dsymForUUID if it
+      // exists, instead of depending on the DebugSymbols preferences being
+      // set.
+      Status kernel_search_error;
+      if (IsKernel() &&
+          (!m_module_sp || !m_module_sp->GetSymbolFileFileSpec())) {
+        if (Symbols::DownloadObjectAndSymbolFile(module_spec,
+                                                 kernel_search_error, true)) {
+          if (FileSystem::Instance().Exists(module_spec.GetFileSpec())) {
+            m_module_sp = std::make_shared<Module>(module_spec.GetFileSpec(),
+                                                   target.GetArchitecture());
+          }
+        }
+      }
+
       if (IsKernel() && !m_module_sp) {
         Stream &s = target.GetDebugger().GetOutputStream();
         s.Printf("WARNING: Unable to locate kernel binary on the debugger "


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