Changed ClangASTImporter to allow finer-grained

management of what allocations remain after an
expression finishes executing.  This saves around
2.5KiB per expression for simple expressions.

llvm-svn: 145342

lldb/include/lldb/Symbol/ClangASTImporter.h

@@ -106,7 +106,8 @@ public:
     
     void BuildNamespaceMap (const clang::NamespaceDecl *decl);
     
-    void PurgeMaps (clang::ASTContext *dest_ast_ctx);
+    void ForgetDestination (clang::ASTContext *dst_ctx);
+    void ForgetSource (clang::ASTContext *dst_ctx, clang::ASTContext *src_ctx);
 private:
     struct DeclOrigin 
     {

lldb/source/Expression/ClangASTSource.cpp

@@ -24,7 +24,20 @@ using namespace lldb_private;
 
 ClangASTSource::~ClangASTSource() 
 {
-    m_ast_importer->PurgeMaps(m_ast_context);
+    m_ast_importer->ForgetDestination(m_ast_context);
+    
+    ClangASTContext *scratch_clang_ast_context = m_target->GetScratchClangASTContext();
+    
+    if (!scratch_clang_ast_context)
+        return;
+    
+    clang::ASTContext *scratch_ast_context = scratch_clang_ast_context->getASTContext();
+    
+    if (!scratch_ast_context)
+        return;
+    
+    if (m_ast_context != scratch_ast_context)
+        m_ast_importer->ForgetSource(scratch_ast_context, m_ast_context);
 }
 
 void

lldb/source/Symbol/ClangASTImporter.cpp

@@ -179,11 +179,32 @@ ClangASTImporter::BuildNamespaceMap(const clang::NamespaceDecl *decl)
 }
 
 void 
-ClangASTImporter::PurgeMaps (clang::ASTContext *dst_ast)
+ClangASTImporter::ForgetDestination (clang::ASTContext *dst_ast)
 {
     m_metadata_map.erase(dst_ast);
 }
 
+void
+ClangASTImporter::ForgetSource (clang::ASTContext *dst_ast, clang::ASTContext *src_ast)
+{
+    ASTContextMetadataSP md = MaybeGetContextMetadata (dst_ast);
+    
+    if (!md)
+        return;
+ 
+    md->m_minions.erase(src_ast);
+    
+    for (OriginMap::iterator iter = md->m_origins.begin();
+         iter != md->m_origins.end();
+         )
+    {
+        if (iter->second.ctx == src_ast)
+            md->m_origins.erase(iter++);
+        else
+            ++iter;
+    }
+}
+
 ClangASTImporter::NamespaceMapCompleter::~NamespaceMapCompleter ()
 {
     return;