Fixed an issue where if we have DWARF in an executable that has multiple languages where these languages use different type systems, you can end up trying to find the actualy definition for a forward declaration for a type, you will call:

TypeSP SymbolFileDWARF::FindDefinitionTypeForDWARFDeclContext (const DWARFDeclContext &dwarf_decl_ctx);

The problem was we might be looking for a type "Foo", and find one from another langauge. Then the DWARFASTParserClang would try to make an AST type using a CompilerType that might return an empty. 

This fix makes sure that when we create a DWARFDeclContext from a DWARFDIE that the DWARFDeclContext we set the language of the DIE. Then when we go to find matches for DWARFDeclContext, we end up with bunch of DIEs. We check each DWARFDIE that we found by asking it for its language and making sure the language is compatible with the type system that we want to use. This keeps us from using the wrong types to resolve forward declarations.

<rdar://problem/25276165>

llvm-svn: 265196

3 files changed, 27 insertions, 3 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
index 4963f8599da..0f02c74fd2e 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
@@ -298,6 +298,7 @@ DWARFDIE::GetDWARFDeclContext (DWARFDeclContext &dwarf_decl_ctx) const
 {
     if (IsValid())
     {
+        dwarf_decl_ctx.SetLanguage(GetLanguage());
         m_die->GetDWARFDeclContext (GetDWARF(), GetCU(), dwarf_decl_ctx);
     }
     else
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
index 4c29447b47b..2452274a293 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
@@ -64,7 +64,8 @@ public:
     };
 
     DWARFDeclContext () :
-        m_entries()
+        m_entries(),
+        m_language(lldb::eLanguageTypeUnknown)
     {
     }
 
@@ -115,10 +116,23 @@ public:
         m_qualified_name.clear();
     }
 
+    lldb::LanguageType
+    GetLanguage() const
+    {
+        return m_language;
+    }
+
+    void
+    SetLanguage(lldb::LanguageType language)
+    {
+        m_language = language;
+    }
+
 protected:
     typedef std::vector<Entry> collection;
     collection m_entries;
     mutable std::string m_qualified_name;
+    lldb::LanguageType m_language;
 };
 
 #endif  // SymbolFileDWARF_DWARFDeclContext_h_
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 36f4d2b8ca4..8b9726fbf2d 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -3698,8 +3698,12 @@ SymbolFileDWARF::FindDefinitionTypeForDWARFDeclContext (const DWARFDeclContext &
             }
             
             const size_t num_matches = die_offsets.size();
-            
-            
+
+            // Get the type system that we are looking to find a type for. We will use this
+            // to ensure any matches we find are in a language that this type system supports
+            const LanguageType language = dwarf_decl_ctx.GetLanguage();
+            TypeSystem *type_system = (language == eLanguageTypeUnknown) ? nullptr : GetTypeSystemForLanguage(language);
+
             if (num_matches)
             {
                 for (size_t i=0; i<num_matches; ++i)
@@ -3709,6 +3713,11 @@ SymbolFileDWARF::FindDefinitionTypeForDWARFDeclContext (const DWARFDeclContext &
                     
                     if (type_die)
                     {
+                        // Make sure type_die's langauge matches the type system we are looking for.
+                        // We don't want to find a "Foo" type from Java if we are looking for a "Foo"
+                        // type for C, C++, ObjC, or ObjC++.
+                        if (type_system && !type_system->SupportsLanguage(type_die.GetLanguage()))
+                            continue;
                         bool try_resolving_type = false;
                         
                         // Don't try and resolve the DIE we are looking for with the DIE itself!