[Lldb-commits] [PATCH] D100338: Add a setting that enables memory to be read from the file cache instead of process when the section LLDB is reading from is read-only

[Augusto Noronha via Phabricator via lldb-commits]

augusto2112 created this revision.
augusto2112 added reviewers: aprantl, jasonmolenda.
augusto2112 requested review of this revision.
Herald added a project: LLDB.
Herald added a subscriber: lldb-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100338

Files:
  lldb/include/lldb/Target/Target.h
  lldb/source/Target/Target.cpp
  lldb/source/Target/TargetProperties.td


Index: lldb/source/Target/TargetProperties.td
===================================================================
--- lldb/source/Target/TargetProperties.td
+++ lldb/source/Target/TargetProperties.td
@@ -175,6 +175,9 @@
   def DebugUtilityExpression: Property<"debug-utility-expression", "Boolean">,
     DefaultFalse,
     Desc<"Enable debugging of LLDB-internal utility expressions.">;
+  def FetchReadonlySectionsFromFileCache: Property<"fetch-readonly-sections-from-file-cache", "Boolean">,
+    DefaultTrue,
+    Desc<"Enables reading bytes from the file cache instead of process when the address LLDB is reading from falls in a readable but not writable section">;
 }
 
 let Definition = "process_experimental" in {
Index: lldb/source/Target/Target.cpp
===================================================================
--- lldb/source/Target/Target.cpp
+++ lldb/source/Target/Target.cpp
@@ -1753,6 +1753,15 @@
   if (!resolved_addr.IsValid())
     resolved_addr = addr;
 
+  if (GetFetchReadonlySectionsFromFileCache()) {
+    SectionSP section_sp(addr.GetSection());
+    if (section_sp) {
+      auto permissions = section_sp->GetPermissions();
+      prefer_file_cache |= (permissions & ePermissionsWritable) == 0 &&
+                          (permissions & ePermissionsReadable) == 1;
+    }
+  }
+
   if (prefer_file_cache) {
     bytes_read = ReadMemoryFromFileCache(resolved_addr, dst, dst_len, error);
     if (bytes_read > 0)
@@ -4355,6 +4364,17 @@
   m_collection_sp->SetPropertyAtIndexAsBoolean(nullptr, idx, debug);
 }
 
+bool TargetProperties::GetFetchReadonlySectionsFromFileCache() const {
+  const uint32_t idx = ePropertyFetchReadonlySectionsFromFileCache;
+  return m_collection_sp->GetPropertyAtIndexAsBoolean(
+      nullptr, idx, g_target_properties[idx].default_uint_value != 0);
+}
+
+void TargetProperties::SetFetchReadonlySectionsFromFileCache(bool b) {
+  const uint32_t idx = ePropertyFetchReadonlySectionsFromFileCache;
+  m_collection_sp->SetPropertyAtIndexAsBoolean(nullptr, idx, b);
+}
+
 // Target::TargetEventData
 
 Target::TargetEventData::TargetEventData(const lldb::TargetSP &target_sp)
Index: lldb/include/lldb/Target/Target.h
===================================================================
--- lldb/include/lldb/Target/Target.h
+++ lldb/include/lldb/Target/Target.h
@@ -231,6 +231,11 @@
 
   bool GetDebugUtilityExpression() const;
 
+  bool GetFetchReadonlySectionsFromFileCache() const;
+
+  void SetFetchReadonlySectionsFromFileCache(bool b);
+
+
 private:
   // Callbacks for m_launch_info.
   void Arg0ValueChangedCallback();


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