Now that SymbolFileDWARF supports having types in completely separate .pcm file with "-fmodules -gmodules", each SymbolFileDWARF can reference module DWARF info by looking in other DWARF files. Then if you have 1000 .o files that each reference one or more .pcm files in their debug info, a simple Module::FindTypes(...) call can end up searching the same .pcm file over and over and over. Now all internal FindTypes methods in classes (ModuleList, Module, SymbolFile) now take an extra argument:

    llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files
    
Each time a SymbolFile::FindTypes() is called, it needs to check the searched_symbol_files list to make sure it hasn't already been asked to find the type and return immediately if it has been checked. This will stop circular dependencies from also crashing LLDB during type queries. 

This has proven to be an issue when debugging large applications on MacOSX that use DWARF in .o files. 

<rdar://problem/24581488>

llvm-svn: 260434

1 files changed, 10 insertions, 6 deletions

diff --git a/lldb/source/Core/Module.cpp b/lldb/source/Core/Module.cpp
index a29456f5b5a..3ada4832e73 100644
--- a/lldb/source/Core/Module.cpp
+++ b/lldb/source/Core/Module.cpp
@@ -933,6 +933,7 @@ Module::FindTypes_Impl (const SymbolContext& sc,
                         const CompilerDeclContext *parent_decl_ctx,
                         bool append,
                         size_t max_matches,
+                        llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                         TypeMap& types)
 {
     Timer scoped_timer(__PRETTY_FUNCTION__, __PRETTY_FUNCTION__);
@@ -940,7 +941,7 @@ Module::FindTypes_Impl (const SymbolContext& sc,
     {
         SymbolVendor *symbols = GetSymbolVendor ();
         if (symbols)
-            return symbols->FindTypes(sc, name, parent_decl_ctx, append, max_matches, types);
+            return symbols->FindTypes(sc, name, parent_decl_ctx, append, max_matches, searched_symbol_files, types);
     }
     return 0;
 }
@@ -954,7 +955,8 @@ Module::FindTypesInNamespace (const SymbolContext& sc,
 {
     const bool append = true;
     TypeMap types_map;
-    size_t num_types = FindTypes_Impl(sc, type_name, parent_decl_ctx, append, max_matches, types_map);
+    llvm::DenseSet<lldb_private::SymbolFile *> searched_symbol_files;
+    size_t num_types = FindTypes_Impl(sc, type_name, parent_decl_ctx, append, max_matches, searched_symbol_files, types_map);
     if (num_types > 0)
         sc.SortTypeList(types_map, type_list);
     return num_types;
@@ -966,7 +968,8 @@ Module::FindFirstType (const SymbolContext& sc,
                        bool exact_match)
 {
     TypeList type_list;
-    const size_t num_matches = FindTypes (sc, name, exact_match, 1, type_list);
+    llvm::DenseSet<lldb_private::SymbolFile *> searched_symbol_files;
+    const size_t num_matches = FindTypes (sc, name, exact_match, 1, searched_symbol_files, type_list);
     if (num_matches)
         return type_list.GetTypeAtIndex(0);
     return TypeSP();
@@ -978,6 +981,7 @@ Module::FindTypes (const SymbolContext& sc,
                    const ConstString &name,
                    bool exact_match,
                    size_t max_matches,
+                   llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                    TypeList& types)
 {
     size_t num_matches = 0;
@@ -1000,7 +1004,7 @@ Module::FindTypes (const SymbolContext& sc,
             exact_match = true;
         }
         ConstString type_basename_const_str (type_basename.c_str());
-        if (FindTypes_Impl(sc, type_basename_const_str, NULL, append, max_matches, typesmap))
+        if (FindTypes_Impl(sc, type_basename_const_str, NULL, append, max_matches, searched_symbol_files, typesmap))
         {
             typesmap.RemoveMismatchedTypes (type_scope, type_basename, type_class, exact_match);
             num_matches = typesmap.GetSize();
@@ -1013,13 +1017,13 @@ Module::FindTypes (const SymbolContext& sc,
         {
             // The "type_name_cstr" will have been modified if we have a valid type class
             // prefix (like "struct", "class", "union", "typedef" etc).
-            FindTypes_Impl(sc, ConstString(type_name_cstr), NULL, append, max_matches, typesmap);
+            FindTypes_Impl(sc, ConstString(type_name_cstr), NULL, append, max_matches, searched_symbol_files, typesmap);
             typesmap.RemoveMismatchedTypes (type_class);
             num_matches = typesmap.GetSize();
         }
         else
         {
-            num_matches = FindTypes_Impl(sc, name, NULL, append, max_matches, typesmap);
+            num_matches = FindTypes_Impl(sc, name, NULL, append, max_matches, searched_symbol_files, typesmap);
         }
     }
     if (num_matches > 0)