[Lldb-commits] [PATCH] D140249: [lldb] Do not deallocate memory after exec

[Alex Langford via Phabricator via lldb-commits]

bulbazord updated this revision to Diff 483692.
bulbazord added a comment.

Add a comment explaining why we do not dealloc after exec


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D140249/new/

https://reviews.llvm.org/D140249

Files:
  lldb/include/lldb/Target/Memory.h
  lldb/source/Target/Memory.cpp
  lldb/source/Target/Process.cpp


Index: lldb/source/Target/Process.cpp
===================================================================
--- lldb/source/Target/Process.cpp
+++ lldb/source/Target/Process.cpp
@@ -542,7 +542,7 @@
   m_notifications.swap(empty_notifications);
   m_image_tokens.clear();
   m_memory_cache.Clear();
-  m_allocated_memory_cache.Clear();
+  m_allocated_memory_cache.Clear(/*did_exec=*/false);
   {
     std::lock_guard<std::recursive_mutex> guard(m_language_runtimes_mutex);
     m_language_runtimes.clear();
@@ -5656,7 +5656,7 @@
   m_dyld_up.reset();
   m_jit_loaders_up.reset();
   m_image_tokens.clear();
-  m_allocated_memory_cache.Clear();
+  m_allocated_memory_cache.Clear(/*did_exec=*/true);
   {
     std::lock_guard<std::recursive_mutex> guard(m_language_runtimes_mutex);
     m_language_runtimes.clear();
Index: lldb/source/Target/Memory.cpp
===================================================================
--- lldb/source/Target/Memory.cpp
+++ lldb/source/Target/Memory.cpp
@@ -332,9 +332,11 @@
 
 AllocatedMemoryCache::~AllocatedMemoryCache() = default;
 
-void AllocatedMemoryCache::Clear() {
+void AllocatedMemoryCache::Clear(bool did_exec) {
   std::lock_guard<std::recursive_mutex> guard(m_mutex);
-  if (m_process.IsAlive()) {
+  // After an exec, the inferior is a new process and these memory regions are
+  // no longer allocated.
+  if (m_process.IsAlive() && !did_exec) {
     PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
     for (pos = m_memory_map.begin(); pos != end; ++pos)
       m_process.DoDeallocateMemory(pos->second->GetBaseAddress());
Index: lldb/include/lldb/Target/Memory.h
===================================================================
--- lldb/include/lldb/Target/Memory.h
+++ lldb/include/lldb/Target/Memory.h
@@ -116,7 +116,7 @@
 
   ~AllocatedMemoryCache();
 
-  void Clear();
+  void Clear(bool did_exec);
 
   lldb::addr_t AllocateMemory(size_t byte_size, uint32_t permissions,
                               Status &error);


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