Backend support for top-level Clang epxressions

This patch adds a new ExecutionPolicy, eExecutionPolicyTopLevel, which
tells the expression parser that the expression should be JITted as top
level code but nothing (except static initializers) should be run.  I
have modified the Clang expression parser to recognize this execution
policy.  On top of the existing patches that support storing IR and
maintaining a map of arbitrary Decls, this is mainly just patching up a
few places in the expression parser.

I intend to submit a patch for review that exposes this functionality
through the "expression" command and through the SB API.  That patch
also includes a testcase for all of this.

<rdar://problem/22864976>

llvm-svn: 264095

1 files changed, 10 insertions, 8 deletions

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
index 3177da358af..6077588b024 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
@@ -51,13 +51,10 @@ public:
     class ClangUserExpressionHelper : public ClangExpressionHelper
     {
     public:
-        ClangUserExpressionHelper (Target &target) :
-            m_target(target)
-        {
-        }
-        
+        ClangUserExpressionHelper(Target &target, bool top_level) : m_target(target), m_top_level(top_level) {}
+
         ~ClangUserExpressionHelper() override = default;
-        
+
         //------------------------------------------------------------------
         /// Return the object that the parser should use when resolving external
         /// values.  May be NULL if everything should be self-contained.
@@ -88,11 +85,16 @@ public:
         clang::ASTConsumer *
         ASTTransformer(clang::ASTConsumer *passthrough) override;
 
+        void
+        CommitPersistentDecls() override;
+
     private:
-        Target                                  &m_target;
+        Target &m_target;
         std::unique_ptr<ClangExpressionDeclMap> m_expr_decl_map_up;
-        std::unique_ptr<ASTStructExtractor> m_struct_extractor_up;         ///< The class that generates the argument struct layout.
+        std::unique_ptr<ASTStructExtractor>
+            m_struct_extractor_up; ///< The class that generates the argument struct layout.
         std::unique_ptr<ASTResultSynthesizer> m_result_synthesizer_up;
+        bool m_top_level;
     };
 
     //------------------------------------------------------------------