<rdar://problem/15191078>

Fixed Module::ResolveSymbolContextForAddress() to be able to also look in the SymbolVendor's SymbolFile's ObjectFile for a more meaningful symbol when a symbol lookup finds a synthetic symbol from the main object file. This will help lookups on MacOSX as the main executable might be stripped, but the dSYM file always has a full symbol table.

llvm-svn: 192510

lldb/include/lldb/Symbol/Symtab.h

@@ -95,6 +95,10 @@ public:
                                                 bool add_mangled,
                                                 NameToIndexMap &name_to_index_map) const;
 
+    ObjectFile *        GetObjectFile()
+                        {
+                            return m_objfile;
+                        }
 protected:
     typedef std::vector<Symbol>         collection;
     typedef collection::iterator        iterator;

lldb/source/Core/Module.cpp

@@ -499,7 +499,39 @@ Module::ResolveSymbolContextForAddress (const Address& so_addr, uint32_t resolve
                 }
 
                 if (sc.symbol)
+                {
+                    if (sc.symbol->IsSynthetic())
+                    {
+                        // We have a synthetic symbol so lets check if the object file
+                        // from the symbol file in the symbol vendor is different than
+                        // the object file for the module, and if so search its symbol
+                        // table to see if we can come up with a better symbol. For example
+                        // dSYM files on MacOSX have an unstripped symbol table inside of
+                        // them.
+                        ObjectFile *symtab_objfile = symtab->GetObjectFile();
+                        if (symtab_objfile && symtab_objfile->IsStripped())
+                        {
+                            SymbolFile *symfile = sym_vendor->GetSymbolFile();
+                            if (symfile)
+                            {
+                                ObjectFile *symfile_objfile = symfile->GetObjectFile();
+                                if (symfile_objfile != symtab_objfile)
+                                {
+                                    Symtab *symfile_symtab = symfile_objfile->GetSymtab();
+                                    if (symfile_symtab)
+                                    {
+                                        Symbol *symbol = symfile_symtab->FindSymbolContainingFileAddress(so_addr.GetFileAddress());
+                                        if (symbol && !symbol->IsSynthetic())
+                                        {
+                                            sc.symbol = symbol;
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
                     resolved_flags |= eSymbolContextSymbol;
+                }
             }
         }
 

lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp

@@ -949,7 +949,7 @@ ObjectFileMachO::IsStripped ()
         }
     }
     if (m_dysymtab.cmd)
-        return m_dysymtab.nlocalsym == 0;
+        return m_dysymtab.nlocalsym <= 1;
     return false;
 }