Added support to the Objective-C language runtime

to find Objective-C class types by looking in the
symbol tables for the individual object files.

I did this as follows:

- I added code to SymbolFileSymtab that vends
  Clang types for symbols matching the pattern
  "_OBJC_CLASS_$_NSMyClassName," making them
  appear as Objective-C classes.  This only occurs
  in modules that do not have debug information,
  since otherwise SymbolFileDWARF would be in
  charge of looking up types.

- I made a new SymbolVendor subclass for the
  Apple Objective-C runtime that is in charge of
  making global lookups of Objective-C types.  It
  currently just sends out type lookup requests to
  the appropriate SymbolFiles, but in the future we
  will probably extend it to query the runtime more
  completely.

I also modified a testcase whose behavior is changed
by the fact that we now actually return an Objective-C
type for __NSCFString.

llvm-svn: 145526

2 files changed, 71 insertions, 1 deletions

diff --git a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
index c3e02d7573f..a824267487d 100644
--- a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
+++ b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
@@ -63,7 +63,8 @@ SymbolFileSymtab::SymbolFileSymtab(ObjectFile* obj_file) :
     m_func_indexes(),
     m_code_indexes(),
     m_data_indexes(),
-    m_addr_indexes()
+    m_addr_indexes(),
+    m_has_objc_symbols(eLazyBoolCalculate)
 {
 }
 
@@ -71,6 +72,27 @@ SymbolFileSymtab::~SymbolFileSymtab()
 {
 }
 
+ClangASTContext &       
+SymbolFileSymtab::GetClangASTContext ()
+{    
+    ClangASTContext &ast = m_obj_file->GetModule()->GetClangASTContext();
+    
+    return ast;
+}
+
+bool
+SymbolFileSymtab::HasObjCSymbols ()
+{
+    if (m_has_objc_symbols == eLazyBoolCalculate)
+    {
+        if (m_obj_file->GetSectionList()->FindSectionByName(ConstString("__objc_data")))
+            m_has_objc_symbols = eLazyBoolYes;
+        else
+            m_has_objc_symbols = eLazyBoolNo;
+    }
+    
+    return m_has_objc_symbols == eLazyBoolYes;
+}
 
 uint32_t
 SymbolFileSymtab::GetAbilities ()
@@ -113,6 +135,11 @@ SymbolFileSymtab::GetAbilities ()
                 symtab->SortSymbolIndexesByValue(m_data_indexes, true);
                 abilities |= GlobalVariables;
             }
+            
+            if (HasObjCSymbols())
+            {
+                abilities |= RuntimeTypes;
+            }
         }
     }
     return abilities;
@@ -352,6 +379,42 @@ SymbolFileSymtab::FindTypes (const lldb_private::SymbolContext& sc, const lldb_p
 {
     if (!append)
         types.Clear();
+    
+    if (HasObjCSymbols())
+    {
+        std::string symbol_name("OBJC_CLASS_$_");
+        symbol_name.append(name.AsCString());
+        ConstString symbol_const_string(symbol_name.c_str());
+        
+        std::vector<uint32_t> indices;
+        
+        if (m_obj_file->GetSymtab()->FindAllSymbolsWithNameAndType(symbol_const_string, lldb::eSymbolTypeRuntime, indices) == 0)
+            return 0;
+        
+        const bool isForwardDecl = false;
+        const bool isInternal = true;
+        
+        ClangASTContext &clang_ast_ctx = GetClangASTContext();
+        
+        lldb::clang_type_t objc_object_type = clang_ast_ctx.CreateObjCClass(name.AsCString(), clang_ast_ctx.GetTranslationUnitDecl(), isForwardDecl, isInternal);
+        
+        Declaration decl;
+        
+        lldb::TypeSP type(new Type (indices[0],
+                                    this,
+                                    name,
+                                    0 /*byte_size*/,
+                                    NULL /*SymbolContextScope*/,
+                                    0 /*encoding_uid*/,
+                                    Type::eEncodingInvalid,
+                                    decl,
+                                    objc_object_type,
+                                    Type::eResolveStateForward));
+        
+        types.Insert(type);
+        
+        return 1;
+    }
 
     return 0;
 }
diff --git a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
index ba43a30424e..d7e58af1182 100644
--- a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
+++ b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
@@ -119,12 +119,19 @@ public:
     GetPluginVersion();
 
 protected:
+    lldb_private::LazyBool  m_has_objc_symbols;
     std::vector<uint32_t>   m_source_indexes;
     std::vector<uint32_t>   m_func_indexes;
     std::vector<uint32_t>   m_code_indexes;
     std::vector<uint32_t>   m_data_indexes;
     std::vector<uint32_t>   m_addr_indexes; // Anything that needs to go into an search by address
 
+    bool
+    HasObjCSymbols ();
+    
+    lldb_private::ClangASTContext &
+    GetClangASTContext ();
+    
 private:
     DISALLOW_COPY_AND_ASSIGN (SymbolFileSymtab);
 };