[Lldb-commits] [PATCH] D109797: Fix rendezvous for rebase_exec=true case

[Emre Kultursay via Phabricator via lldb-commits]

emrekultursay created this revision.
emrekultursay requested review of this revision.
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When rebase_exec=true in DidAttach(), all modules are loaded
before the rendezvous breakpoint is set, which means the
LoadInterpreterModule() method is not called and m_interpreter_module
is not initialized.

This causes the very first rendezvous breakpoint hit (with
m_initial_modules_added=false) to accidentally unload the
module_sp that corresponds to the dynamic loader.

This bug was causing the rendezvous mechanism to not work
in Android 28, which this CL fixes.

Test: Verified rendezvous on Android 28 and 29


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D109797

Files:
  lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp


Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -442,14 +442,18 @@
         if (module_sp->GetObjectFile()->GetBaseAddress().GetLoadAddress(
                 &m_process->GetTarget()) == m_interpreter_base &&
             module_sp != m_interpreter_module.lock()) {
-          // If this is a duplicate instance of ld.so, unload it.  We may end up
-          // with it if we load it via a different path than before (symlink
-          // vs real path).
-          // TODO: remove this once we either fix library matching or avoid
-          // loading the interpreter when setting the rendezvous breakpoint.
-          UnloadSections(module_sp);
-          loaded_modules.Remove(module_sp);
-          continue;
+          if (m_interpreter_module.lock() == nullptr) {
+            m_interpreter_module = module_sp;
+          } else {
+            // If this is a duplicate instance of ld.so, unload it.  We may end up
+            // with it if we load it via a different path than before (symlink
+            // vs real path).
+            // TODO: remove this once we either fix library matching or avoid
+            // loading the interpreter when setting the rendezvous breakpoint.
+            UnloadSections(module_sp);
+            loaded_modules.Remove(module_sp);
+            continue;
+          }
         }
 
         loaded_modules.AppendIfNeeded(module_sp);


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