[lldb/breakpad] Use new line table constructor

labath · labath · commit 5e70f4bdc159 · 2020-01-21T15:04:27.000+01:00
The old construction method can be quadratic for some inputs. This
approach guarantees a reasonable performance.
diff --git a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp
@@ -694,18 +694,18 @@ void SymbolFileBreakpad::ParseLineTableAndSupportFiles(CompileUnit &cu,
          "How did we create compile units without a base address?");
 
   SupportFileMap map;
-  data.line_table_up = std::make_unique<LineTable>(&cu);
-  std::unique_ptr<LineSequence> line_seq_up(
-      data.line_table_up->CreateLineSequenceContainer());
+  std::vector<std::unique_ptr<LineSequence>> sequences;
+  std::unique_ptr<LineSequence> line_seq_up =
+      LineTable::CreateLineSequenceContainer();
   llvm::Optional<addr_t> next_addr;
   auto finish_sequence = [&]() {
-    data.line_table_up->AppendLineEntryToSequence(
+    LineTable::AppendLineEntryToSequence(
         line_seq_up.get(), *next_addr, /*line*/ 0, /*column*/ 0,
         /*file_idx*/ 0, /*is_start_of_statement*/ false,
         /*is_start_of_basic_block*/ false, /*is_prologue_end*/ false,
         /*is_epilogue_begin*/ false, /*is_terminal_entry*/ true);
-    data.line_table_up->InsertSequence(line_seq_up.get());
-    line_seq_up->Clear();
+    sequences.push_back(std::move(line_seq_up));
+    line_seq_up = LineTable::CreateLineSequenceContainer();
   };
 
   LineIterator It(*m_objfile_sp, Record::Func, data.bookmark),
@@ -722,7 +722,7 @@ void SymbolFileBreakpad::ParseLineTableAndSupportFiles(CompileUnit &cu,
       // Discontiguous entries. Finish off the previous sequence and reset.
       finish_sequence();
     }
-    data.line_table_up->AppendLineEntryToSequence(
+    LineTable::AppendLineEntryToSequence(
         line_seq_up.get(), record->Address, record->LineNum, /*column*/ 0,
         map[record->FileNum], /*is_start_of_statement*/ true,
         /*is_start_of_basic_block*/ false, /*is_prologue_end*/ false,
@@ -731,6 +731,7 @@ void SymbolFileBreakpad::ParseLineTableAndSupportFiles(CompileUnit &cu,
   }
   if (next_addr)
     finish_sequence();
+  data.line_table_up = std::make_unique<LineTable>(&cu, std::move(sequences));
   data.support_files = map.translate(cu.GetPrimaryFile(), *m_files);
 }
 
