Skip to content

Reapply "[lldb] Remove UnwindPlan::Row shared_ptrs (https://github.com/llvm/llvm-project/pull/132370)" #134821

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Apr 9, 2025

Conversation

labath
Copy link
Collaborator

@labath labath commented Apr 8, 2025

This reverts commit 48864a5, reapplying
d7cea2b. It also fixes the dangling
pointers caused by the previous version by creating copies of the Rows
in x86AssemblyInspectionEngine.

labath added 2 commits April 8, 2025 10:30
This reverts commit 48864a5, reapplying
d7cea2b. It also fixes the dangling
pointers caused by the previous version by creating copies of the Rows
in x86AssemblyInspectionEngine.
@labath labath requested review from bulbazord and clayborg April 8, 2025 09:30
@labath labath requested a review from JDevlieghere as a code owner April 8, 2025 09:30
@llvmbot llvmbot added the lldb label Apr 8, 2025
@llvmbot
Copy link
Member

llvmbot commented Apr 8, 2025

@llvm/pr-subscribers-lldb

Author: Pavel Labath (labath)

Changes

This reverts commit 48864a5, reapplying
d7cea2b. It also fixes the dangling
pointers caused by the previous version by creating copies of the Rows
in x86AssemblyInspectionEngine.


Full diff: https://github.com/llvm/llvm-project/pull/134821.diff

3 Files Affected:

  • (modified) lldb/include/lldb/Symbol/UnwindPlan.h (+5-22)
  • (modified) lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp (+9-9)
  • (modified) lldb/source/Symbol/UnwindPlan.cpp (+16-16)
diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h b/lldb/include/lldb/Symbol/UnwindPlan.h
index 6640a23a3e868..0feb20b12e184 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -428,8 +428,6 @@ class UnwindPlan {
     bool m_unspecified_registers_are_undefined = false;
   }; // class Row
 
-  typedef std::shared_ptr<Row> RowSP;
-
   UnwindPlan(lldb::RegisterKind reg_kind)
       : m_register_kind(reg_kind), m_return_addr_register(LLDB_INVALID_REGNUM),
         m_plan_is_sourced_from_compiler(eLazyBoolCalculate),
@@ -437,25 +435,10 @@ class UnwindPlan {
         m_plan_is_for_signal_trap(eLazyBoolCalculate) {}
 
   // Performs a deep copy of the plan, including all the rows (expensive).
-  UnwindPlan(const UnwindPlan &rhs)
-      : m_plan_valid_ranges(rhs.m_plan_valid_ranges),
-        m_register_kind(rhs.m_register_kind),
-        m_return_addr_register(rhs.m_return_addr_register),
-        m_source_name(rhs.m_source_name),
-        m_plan_is_sourced_from_compiler(rhs.m_plan_is_sourced_from_compiler),
-        m_plan_is_valid_at_all_instruction_locations(
-            rhs.m_plan_is_valid_at_all_instruction_locations),
-        m_plan_is_for_signal_trap(rhs.m_plan_is_for_signal_trap),
-        m_lsda_address(rhs.m_lsda_address),
-        m_personality_func_addr(rhs.m_personality_func_addr) {
-    m_row_list.reserve(rhs.m_row_list.size());
-    for (const RowSP &row_sp : rhs.m_row_list)
-      m_row_list.emplace_back(new Row(*row_sp));
-  }
+  UnwindPlan(const UnwindPlan &rhs) = default;
+  UnwindPlan &operator=(const UnwindPlan &rhs) = default;
+
   UnwindPlan(UnwindPlan &&rhs) = default;
-  UnwindPlan &operator=(const UnwindPlan &rhs) {
-    return *this = UnwindPlan(rhs); // NB: moving from a temporary (deep) copy
-  }
   UnwindPlan &operator=(UnwindPlan &&) = default;
 
   ~UnwindPlan() = default;
@@ -487,7 +470,7 @@ class UnwindPlan {
   uint32_t GetInitialCFARegister() const {
     if (m_row_list.empty())
       return LLDB_INVALID_REGNUM;
-    return m_row_list.front()->GetCFAValue().GetRegisterNumber();
+    return m_row_list.front().GetCFAValue().GetRegisterNumber();
   }
 
   // This UnwindPlan may not be valid at every address of the function span.
@@ -570,7 +553,7 @@ class UnwindPlan {
   }
 
 private:
-  std::vector<RowSP> m_row_list;
+  std::vector<Row> m_row_list;
   std::vector<AddressRange> m_plan_valid_ranges;
   lldb::RegisterKind m_register_kind; // The RegisterKind these register numbers
                                       // are in terms of - will need to be
diff --git a/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp b/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp
index 3eaa2f33fce3e..823c6505d90cf 100644
--- a/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp
+++ b/lldb/source/Plugins/UnwindAssembly/x86/x86AssemblyInspectionEngine.cpp
@@ -1338,25 +1338,25 @@ bool x86AssemblyInspectionEngine::AugmentUnwindPlanFromCallSite(
   if (unwind_plan.GetRowCount() < 2)
     return false;
 
-  const UnwindPlan::Row *first_row = unwind_plan.GetRowAtIndex(0);
-  if (first_row->GetOffset() != 0)
+  UnwindPlan::Row first_row = *unwind_plan.GetRowAtIndex(0);
+  if (first_row.GetOffset() != 0)
     return false;
-  uint32_t cfa_reg = first_row->GetCFAValue().GetRegisterNumber();
+  uint32_t cfa_reg = first_row.GetCFAValue().GetRegisterNumber();
   if (unwind_plan.GetRegisterKind() != eRegisterKindLLDB) {
     cfa_reg = reg_ctx->ConvertRegisterKindToRegisterNumber(
         unwind_plan.GetRegisterKind(),
-        first_row->GetCFAValue().GetRegisterNumber());
+        first_row.GetCFAValue().GetRegisterNumber());
   }
   if (cfa_reg != m_lldb_sp_regnum ||
-      first_row->GetCFAValue().GetOffset() != m_wordsize)
+      first_row.GetCFAValue().GetOffset() != m_wordsize)
     return false;
 
-  const UnwindPlan::Row *original_last_row = unwind_plan.GetLastRow();
+  UnwindPlan::Row original_last_row = *unwind_plan.GetLastRow();
 
   size_t offset = 0;
   int row_id = 1;
   bool unwind_plan_updated = false;
-  UnwindPlan::Row row = *first_row;
+  UnwindPlan::Row row = first_row;
 
   // After a mid-function epilogue we will need to re-insert the original
   // unwind rules so unwinds work for the remainder of the function.  These
@@ -1380,7 +1380,7 @@ bool x86AssemblyInspectionEngine::AugmentUnwindPlanFromCallSite(
       continue;
 
     if (reinstate_unwind_state) {
-      row = *original_last_row;
+      row = original_last_row;
       row.SetOffset(offset);
       unwind_plan.AppendRow(row);
       reinstate_unwind_state = false;
@@ -1521,7 +1521,7 @@ bool x86AssemblyInspectionEngine::AugmentUnwindPlanFromCallSite(
         if (ret_pattern_p()) {
           row.SetOffset(offset);
           row.GetCFAValue().SetIsRegisterPlusOffset(
-              first_row->GetCFAValue().GetRegisterNumber(), m_wordsize);
+              first_row.GetCFAValue().GetRegisterNumber(), m_wordsize);
 
           unwind_plan.InsertRow(row);
           unwind_plan_updated = true;
diff --git a/lldb/source/Symbol/UnwindPlan.cpp b/lldb/source/Symbol/UnwindPlan.cpp
index cfa8eefaa55bb..48999aadab1e2 100644
--- a/lldb/source/Symbol/UnwindPlan.cpp
+++ b/lldb/source/Symbol/UnwindPlan.cpp
@@ -391,29 +391,29 @@ bool UnwindPlan::Row::operator==(const UnwindPlan::Row &rhs) const {
 }
 
 void UnwindPlan::AppendRow(Row row) {
-  if (m_row_list.empty() || m_row_list.back()->GetOffset() != row.GetOffset())
-    m_row_list.push_back(std::make_shared<Row>(std::move(row)));
+  if (m_row_list.empty() || m_row_list.back().GetOffset() != row.GetOffset())
+    m_row_list.push_back(std::move(row));
   else
-    *m_row_list.back() = std::move(row);
+    m_row_list.back() = std::move(row);
 }
 
 struct RowLess {
-  bool operator()(addr_t a, const UnwindPlan::RowSP &b) const {
-    return a < b->GetOffset();
+  bool operator()(addr_t a, const UnwindPlan::Row &b) const {
+    return a < b.GetOffset();
   }
-  bool operator()(const UnwindPlan::RowSP &a, addr_t b) const {
-    return a->GetOffset() < b;
+  bool operator()(const UnwindPlan::Row &a, addr_t b) const {
+    return a.GetOffset() < b;
   }
 };
 
 void UnwindPlan::InsertRow(Row row, bool replace_existing) {
   auto it = llvm::lower_bound(m_row_list, row.GetOffset(), RowLess());
-  if (it == m_row_list.end() || it->get()->GetOffset() > row.GetOffset())
-    m_row_list.insert(it, std::make_shared<Row>(std::move(row)));
+  if (it == m_row_list.end() || it->GetOffset() > row.GetOffset())
+    m_row_list.insert(it, std::move(row));
   else {
-    assert(it->get()->GetOffset() == row.GetOffset());
+    assert(it->GetOffset() == row.GetOffset());
     if (replace_existing)
-      **it = std::move(row);
+      *it = std::move(row);
   }
 }
 
@@ -425,7 +425,7 @@ UnwindPlan::GetRowForFunctionOffset(std::optional<int> offset) const {
     return nullptr;
   // upper_bound returns the row strictly greater than our desired offset, which
   // means that the row before it is a match.
-  return std::prev(it)->get();
+  return &*std::prev(it);
 }
 
 bool UnwindPlan::IsValidRowIndex(uint32_t idx) const {
@@ -434,7 +434,7 @@ bool UnwindPlan::IsValidRowIndex(uint32_t idx) const {
 
 const UnwindPlan::Row *UnwindPlan::GetRowAtIndex(uint32_t idx) const {
   if (idx < m_row_list.size())
-    return m_row_list[idx].get();
+    return &m_row_list[idx];
   LLDB_LOG(GetLog(LLDBLog::Unwind),
            "error: UnwindPlan::GetRowAtIndex(idx = {0}) invalid index "
            "(number rows is {1})",
@@ -448,7 +448,7 @@ const UnwindPlan::Row *UnwindPlan::GetLastRow() const {
              "UnwindPlan::GetLastRow() when rows are empty");
     return nullptr;
   }
-  return m_row_list.back().get();
+  return &m_row_list.back();
 }
 
 bool UnwindPlan::PlanValidAtAddress(Address addr) const {
@@ -567,9 +567,9 @@ void UnwindPlan::Dump(Stream &s, Thread *thread, lldb::addr_t base_addr) const {
       range.Dump(&s, target_sp.get(), Address::DumpStyleSectionNameOffset);
     s.EOL();
   }
-  for (const auto &[index, row_sp] : llvm::enumerate(m_row_list)) {
+  for (const auto &[index, row] : llvm::enumerate(m_row_list)) {
     s.Format("row[{0}]: ", index);
-    row_sp->Dump(s, this, thread, base_addr);
+    row.Dump(s, this, thread, base_addr);
     s << "\n";
   }
 }

Copy link
Member

@JDevlieghere JDevlieghere left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

🚀

Copy link
Member

@bulbazord bulbazord left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

🫡

@labath labath merged commit e348173 into llvm:main Apr 9, 2025
12 checks passed
@labath labath deleted the uaf branch April 9, 2025 06:22
var-const pushed a commit to ldionne/llvm-project that referenced this pull request Apr 17, 2025
This reverts commit
llvm@48864a5,
reapplying llvm@d7cea2b.
It also fixes the dangling
pointers caused by the previous version by creating copies of the Rows
in x86AssemblyInspectionEngine.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
Projects
None yet
Development

Successfully merging this pull request may close these issues.

4 participants