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diff --git a/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h b/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h
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+++ b/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h
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+//===-- ASTStructExtractor.h ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_ASTStructExtractor_h_
+#define liblldb_ASTStructExtractor_h_
+
+#include "ClangExpressionVariable.h"
+#include "ClangFunctionCaller.h"
+
+#include "clang/Sema/SemaConsumer.h"
+#include "lldb/Core/ClangForward.h"
+
+namespace lldb_private {
+    
+//----------------------------------------------------------------------
+/// @class ASTStructExtractor ASTStructExtractor.h "lldb/Expression/ASTStructExtractor.h"
+/// @brief Extracts and describes the argument structure for a wrapped function.
+///
+/// This pass integrates with ClangFunctionCaller, which calls functions with custom
+/// sets of arguments.  To avoid having to implement the full calling convention
+/// for the target's architecture, ClangFunctionCaller writes a simple wrapper
+/// function that takes a pointer to an argument structure that contains room
+/// for the address of the function to be called, the values of all its
+/// arguments, and room for the function's return value.
+///
+/// The definition of this struct is itself in the body of the wrapper function,
+/// so Clang does the structure layout itself.  ASTStructExtractor reads through
+/// the AST for the wrapper function and finds the struct.
+//----------------------------------------------------------------------
+class ASTStructExtractor : public clang::SemaConsumer
+{
+public:
+    //----------------------------------------------------------------------
+    /// Constructor
+    ///
+    /// @param[in] passthrough
+    ///     Since the ASTs must typically go through to the Clang code generator
+    ///     in order to produce LLVM IR, this SemaConsumer must allow them to
+    ///     pass to the next step in the chain after processing.  Passthrough is
+    ///     the next ASTConsumer, or NULL if none is required.
+    ///
+    /// @param[in] struct_name
+    ///     The name of the structure to extract from the wrapper function.
+    ///
+    /// @param[in] function
+    ///     The caller object whose members should be populated with information
+    ///     about the argument struct.  ClangFunctionCaller friends ASTStructExtractor
+    ///     for this purpose.
+    //----------------------------------------------------------------------
+    ASTStructExtractor(clang::ASTConsumer *passthrough,
+                       const char *struct_name,
+                       ClangFunctionCaller &function);
+    
+    //----------------------------------------------------------------------
+    /// Destructor
+    //----------------------------------------------------------------------
+    ~ASTStructExtractor() override;
+    
+    //----------------------------------------------------------------------
+    /// Link this consumer with a particular AST context
+    ///
+    /// @param[in] Context
+    ///     This AST context will be used for types and identifiers, and also
+    ///     forwarded to the passthrough consumer, if one exists.
+    //----------------------------------------------------------------------
+    void Initialize(clang::ASTContext &Context) override;
+    
+    //----------------------------------------------------------------------
+    /// Examine a list of Decls to find the function $__lldb_expr and 
+    /// transform its code
+    ///
+    /// @param[in] D
+    ///     The list of Decls to search.  These may contain LinkageSpecDecls,
+    ///     which need to be searched recursively.  That job falls to
+    ///     TransformTopLevelDecl.
+    //----------------------------------------------------------------------
+    bool HandleTopLevelDecl(clang::DeclGroupRef D) override;
+    
+    //----------------------------------------------------------------------
+    /// Passthrough stub
+    //----------------------------------------------------------------------
+    void HandleTranslationUnit(clang::ASTContext &Ctx) override;
+    
+    //----------------------------------------------------------------------
+    /// Passthrough stub
+    //----------------------------------------------------------------------
+    void HandleTagDeclDefinition(clang::TagDecl *D) override;
+    
+    //----------------------------------------------------------------------
+    /// Passthrough stub
+    //----------------------------------------------------------------------
+    void CompleteTentativeDefinition(clang::VarDecl *D) override;
+    
+    //----------------------------------------------------------------------
+    /// Passthrough stub
+    //----------------------------------------------------------------------
+    void HandleVTable(clang::CXXRecordDecl *RD) override;
+    
+    //----------------------------------------------------------------------
+    /// Passthrough stub
+    //----------------------------------------------------------------------
+    void PrintStats() override;
+    
+    //----------------------------------------------------------------------
+    /// Set the Sema object to use when performing transforms, and pass it on
+    ///
+    /// @param[in] S
+    ///     The Sema to use.  Because Sema isn't externally visible, this class
+    ///     casts it to an Action for actual use.
+    //----------------------------------------------------------------------
+    void InitializeSema(clang::Sema &S) override;
+    
+    //----------------------------------------------------------------------
+    /// Reset the Sema to NULL now that transformations are done
+    //----------------------------------------------------------------------
+    void ForgetSema() override;
+
+private:
+    //----------------------------------------------------------------------
+    /// Hunt the given FunctionDecl for the argument struct and place
+    /// information about it into m_function
+    ///
+    /// @param[in] F
+    ///     The FunctionDecl to hunt.
+    //----------------------------------------------------------------------
+    void
+    ExtractFromFunctionDecl(clang::FunctionDecl* F);
+    
+    //----------------------------------------------------------------------
+    /// Hunt the given Decl for FunctionDecls named the same as the wrapper
+    /// function name, recursing as necessary through LinkageSpecDecls, and 
+    /// calling ExtractFromFunctionDecl on anything that was found
+    ///
+    /// @param[in] D
+    ///     The Decl to hunt.
+    //----------------------------------------------------------------------
+    void
+    ExtractFromTopLevelDecl(clang::Decl* D);
+    
+    clang::ASTContext              *m_ast_context;          ///< The AST context to use for identifiers and types.
+    clang::ASTConsumer             *m_passthrough;          ///< The ASTConsumer down the chain, for passthrough.  NULL if it's a SemaConsumer.
+    clang::SemaConsumer            *m_passthrough_sema;     ///< The SemaConsumer down the chain, for passthrough.  NULL if it's an ASTConsumer.
+    clang::Sema                    *m_sema;                 ///< The Sema to use.
+    clang::Action                  *m_action;               ///< The Sema to use, cast to an Action so it's usable.
+    
+    ClangFunctionCaller            &m_function;             ///< The function to populate with information about the argument structure.
+    std::string                     m_struct_name;          ///< The name of the structure to extract.
+};
+    
+} // namespace lldb_private
+
+#endif // liblldb_ASTStructExtractor_h_