Fix DW_AT_specification handling in DWO files

[labath]

Summary

We were trying to get a DWARFDIE from a CompileUnit belonging to a DWO file. However, this
function does not understand the die encoding used by the DWO files. Instead use GetDIE on the
SymbolFileDWARF, which is overriden in DWO to do the right thing.

[tberghammer]

LGTM

lldb/trunk/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/Makefile

+LEVEL = ../../../make
+
+CXX_SOURCES := file1.cpp file2.cpp
+
+include $(LEVEL)/Makefile.rules

lldb/trunk/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/TestSymbolContextTwoFiles.py

+"""
+Test SBSymbolContext APIs.
+"""
+
+from __future__ import print_function
+
+import os
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class SymbolContextTwoFilesTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @add_test_categories(['pyapi'])
+    def test_lookup_by_address(self):
+        """Test lookup by address in a module with multiple compilation units"""
+        self.build()
+        exe = os.path.join(os.getcwd(), "a.out")
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+
+        module = target.GetModuleAtIndex(0)
+        self.assertTrue(module.IsValid())
+        for symbol_name in ["struct1::f()", "struct2::f()"]:
+            sc_list = module.FindFunctions(symbol_name, lldb.eSymbolTypeCode)
+            self.assertTrue(1, sc_list.GetSize())
+            symbol_address = sc_list.GetContextAtIndex(0).GetSymbol().GetStartAddress()
+            self.assertTrue(symbol_address.IsValid())
+            sc_by_address = module.ResolveSymbolContextForAddress(symbol_address, lldb.eSymbolContextFunction)
+            self.assertEqual(symbol_name, sc_by_address.GetFunction().GetName())

lldb/trunk/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/decls.h

+struct struct1
+{
+    static void
+    f();
+};
+
+struct struct2
+{
+    static void
+    f();
+};

lldb/trunk/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/file1.cpp

+#include "decls.h"
+
+void
+struct1::f()
+{
+}
+
+int main()
+{
+    struct1::f();
+    struct2::f();
+    return 0;
+}

lldb/trunk/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/file2.cpp

+#include "decls.h"
+
+void
+struct2::f()
+{
+}

lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp

) const
     }
 
     if (ranges.IsEmpty() || name == NULL || mangled == NULL)
     {
         for (const DIERef& die_ref : die_refs)
         {
             if (die_ref.die_offset != DW_INVALID_OFFSET)
             {
-                DWARFDIE die = dwarf2Data->DebugInfo()->GetDIE(die_ref);
+                DWARFDIE die = dwarf2Data->GetDIE(die_ref);
                 if (die)
                     die.GetDIE()->GetDIENamesAndRanges(die.GetDWARF(), die.GetCU(), name, mangled, ranges, decl_file, decl_line, decl_column, call_file, call_line, call_column);
             }
         }
     }
     return !ranges.IsEmpty();
 }