Import LLVM, at r72732.

1 files changed, 297 insertions, 0 deletions

diff --git a/include/llvm/Linker.h b/include/llvm/Linker.h
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+//===- llvm/Linker.h - Module Linker Interface ------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the interface to the module/file/archive linker.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LINKER_H
+#define LLVM_LINKER_H
+
+#include "llvm/System/Path.h"
+#include <memory>
+#include <vector>
+
+namespace llvm {
+
+class Module;
+
+/// This class provides the core functionality of linking in LLVM. It retains a
+/// Module object which is the composite of the modules and libraries linked
+/// into it. The composite Module can be retrieved via the getModule() method.
+/// In this case the Linker still retains ownership of the Module. If the
+/// releaseModule() method is used, the ownership of the Module is transferred
+/// to the caller and the Linker object is only suitable for destruction.
+/// The Linker can link Modules from memory, bitcode files, or bitcode
+/// archives.  It retains a set of search paths in which to find any libraries
+/// presented to it. By default, the linker will generate error and warning
+/// messages to std::cerr but this capability can be turned off with the
+/// QuietWarnings and QuietErrors flags. It can also be instructed to verbosely
+/// print out the linking actions it is taking with the Verbose flag.
+/// @brief The LLVM Linker.
+class Linker {
+
+  /// @name Types
+  /// @{
+  public:
+    /// This type is used to pass the linkage items (libraries and files) to
+    /// the LinkItems function. It is composed of string/bool pairs. The string
+    /// provides the name of the file or library (as with the -l option). The
+    /// bool should be true for libraries and false for files, signifying
+    /// "isLibrary".
+    /// @brief A list of linkage items
+    typedef std::vector<std::pair<std::string,bool> > ItemList;
+
+    /// This enumeration is used to control various optional features of the
+    /// linker.
+    enum ControlFlags {
+      Verbose       = 1, ///< Print to std::cerr what steps the linker is taking
+      QuietWarnings = 2, ///< Don't print warnings to std::cerr.
+      QuietErrors   = 4  ///< Don't print errors to std::cerr.
+    };
+
+  /// @}
+  /// @name Constructors
+  /// @{
+  public:
+    /// Construct the Linker with an empty module which will be given the
+    /// name \p progname. \p progname will also be used for error messages.
+    /// @brief Construct with empty module
+    Linker(
+        const std::string& progname, ///< name of tool running linker
+        const std::string& modulename, ///< name of linker's end-result module
+        unsigned Flags = 0  ///< ControlFlags (one or more |'d together)
+    );
+
+    /// Construct the Linker with a previously defined module, \p aModule. Use
+    /// \p progname for the name of the program in error messages.
+    /// @brief Construct with existing module
+    Linker(const std::string& progname, Module* aModule, unsigned Flags = 0);
+
+    /// Destruct the Linker.
+    /// @brief Destructor
+    ~Linker();
+
+  /// @}
+  /// @name Accessors
+  /// @{
+  public:
+    /// This method gets the composite module into which linking is being
+    /// done. The Composite module starts out empty and accumulates modules
+    /// linked into it via the various LinkIn* methods. This method does not
+    /// release the Module to the caller. The Linker retains ownership and will
+    /// destruct the Module when the Linker is destructed.
+    /// @see releaseModule
+    /// @brief Get the linked/composite module.
+    Module* getModule() const { return Composite; }
+
+    /// This method releases the composite Module into which linking is being
+    /// done. Ownership of the composite Module is transferred to the caller who
+    /// must arrange for its destruct. After this method is called, the Linker
+    /// terminates the linking session for the returned Module. It will no
+    /// longer utilize the returned Module but instead resets itself for
+    /// subsequent linking as if the constructor had been called. The Linker's
+    /// LibPaths and flags to be reset, and memory will be released.
+    /// @brief Release the linked/composite module.
+    Module* releaseModule();
+
+    /// This method gets the list of libraries that form the path that the
+    /// Linker will search when it is presented with a library name.
+    /// @brief Get the Linkers library path
+    const std::vector<sys::Path>& getLibPaths() const { return LibPaths; }
+
+    /// This method returns an error string suitable for printing to the user.
+    /// The return value will be empty unless an error occurred in one of the
+    /// LinkIn* methods. In those cases, the LinkIn* methods will have returned
+    /// true, indicating an error occurred. At most one error is retained so
+    /// this function always returns the last error that occurred. Note that if
+    /// the Quiet control flag is not set, the error string will have already
+    /// been printed to std::cerr.
+    /// @brief Get the text of the last error that occurred.
+    const std::string& getLastError() const { return Error; }
+
+  /// @}
+  /// @name Mutators
+  /// @{
+  public:
+    /// Add a path to the list of paths that the Linker will search. The Linker
+    /// accumulates the set of libraries added
+    /// library paths for the target platform. The standard libraries will
+    /// always be searched last. The added libraries will be searched in the
+    /// order added.
+    /// @brief Add a path.
+    void addPath(const sys::Path& path);
+
+    /// Add a set of paths to the list of paths that the linker will search. The
+    /// Linker accumulates the set of libraries added. The \p paths will be
+    /// added to the end of the Linker's list. Order will be retained.
+    /// @brief Add a set of paths.
+    void addPaths(const std::vector<std::string>& paths);
+
+    /// This method augments the Linker's list of library paths with the system
+    /// paths of the host operating system, include LLVM_LIB_SEARCH_PATH.
+    /// @brief Add the system paths.
+    void addSystemPaths();
+
+    /// Control optional linker behavior by setting a group of flags. The flags
+    /// are defined in the ControlFlags enumeration.
+    /// @see ControlFlags
+    /// @brief Set control flags.
+    void setFlags(unsigned flags) { Flags = flags; }
+
+    /// This method is the main interface to the linker. It can be used to
+    /// link a set of linkage items into a module. A linkage item is either a
+    /// file name with fully qualified path, or a library for which the Linker's
+    /// LibraryPath will be utilized to locate the library. The bool value in
+    /// the LinkItemKind should be set to true for libraries.  This function
+    /// allows linking to preserve the order of specification associated with
+    /// the command line, or for other purposes. Each item will be linked in
+    /// turn as it occurs in \p Items.
+    /// @returns true if an error occurred, false otherwise
+    /// @see LinkItemKind
+    /// @see getLastError
+    /// @throws nothing
+    bool LinkInItems (
+      const ItemList& Items, ///< Set of libraries/files to link in
+      ItemList& NativeItems  ///< Output list of native files/libs
+    );
+
+    /// This function links the bitcode \p Files into the composite module.
+    /// Note that this does not do any linking of unresolved symbols. The \p
+    /// Files are all completely linked into \p HeadModule regardless of
+    /// unresolved symbols. This function just loads each bitcode file and
+    /// calls LinkInModule on them.
+    /// @returns true if an error occurs, false otherwise
+    /// @see getLastError
+    /// @brief Link in multiple files.
+    bool LinkInFiles (
+      const std::vector<sys::Path> & Files ///< Files to link in
+    );
+
+    /// This function links a single bitcode file, \p File, into the composite
+    /// module. Note that this does not attempt to resolve symbols. This method
+    /// just loads the bitcode file and calls LinkInModule on it. If an error
+    /// occurs, the Linker's error string is set.
+    /// @returns true if an error occurs, false otherwise
+    /// @see getLastError
+    /// @brief Link in a single file.
+    bool LinkInFile(
+      const sys::Path& File, ///< File to link in.
+      bool &is_native        ///< Indicates if the file is native object file
+    );
+
+    /// This function provides a way to selectively link in a set of modules,
+    /// found in libraries, based on the unresolved symbols in the composite
+    /// module. Each item in \p Libraries should be the base name of a library,
+    /// as if given with the -l option of a linker tool.  The Linker's LibPaths
+    /// are searched for the \p Libraries and any found will be linked in with
+    /// LinkInArchive.  If an error occurs, the Linker's error string is set.
+    /// @see LinkInArchive
+    /// @see getLastError
+    /// @returns true if an error occurs, false otherwise
+    /// @brief Link libraries into the module
+    bool LinkInLibraries (
+      const std::vector<std::string> & Libraries ///< Libraries to link in
+    );
+
+    /// This function provides a way to selectively link in a set of modules,
+    /// found in one library, based on the unresolved symbols in the composite
+    /// module.The \p Library should be the base name of a library, as if given
+    /// with the -l option of a linker tool. The Linker's LibPaths are searched
+    /// for the \p Library and if found, it will be linked in with via the
+    /// LinkInArchive method. If an error occurs, the Linker's error string is
+    /// set.
+    /// @see LinkInArchive
+    /// @see getLastError
+    /// @returns true if an error occurs, false otherwise
+    /// @brief Link one library into the module
+    bool LinkInLibrary (
+      const std::string& Library, ///< The library to link in
+      bool& is_native             ///< Indicates if lib a native library
+    );
+
+    /// This function links one bitcode archive, \p Filename, into the module.
+    /// The archive is searched to resolve outstanding symbols. Any modules in
+    /// the archive that resolve outstanding symbols will be linked in. The
+    /// library is searched repeatedly until no more modules that resolve
+    /// symbols can be found. If an error occurs, the error string is  set.
+    /// To speed up this function, ensure the the archive has been processed
+    /// llvm-ranlib or the S option was given to llvm-ar when the archive was
+    /// created. These tools add a symbol table to the archive which makes the
+    /// search for undefined symbols much faster.
+    /// @see getLastError
+    /// @returns true if an error occurs, otherwise false.
+    /// @brief Link in one archive.
+    bool LinkInArchive(
+      const sys::Path& Filename, ///< Filename of the archive to link
+      bool& is_native            ///<  Indicates if archive is a native archive
+    );
+
+    /// This method links the \p Src module into the Linker's Composite module
+    /// by calling LinkModules.  All the other LinkIn* methods eventually
+    /// result in calling this method to link a Module into the Linker's
+    /// composite.
+    /// @see LinkModules
+    /// @returns True if an error occurs, false otherwise.
+    /// @brief Link in a module.
+    bool LinkInModule(
+      Module* Src,              ///< Module linked into \p Dest
+      std::string* ErrorMsg = 0 /// Error/diagnostic string
+    ) { 
+      return LinkModules(Composite, Src, ErrorMsg ); 
+    }
+
+    /// This is the heart of the linker. This method will take unconditional
+    /// control of the \p Src module and link it into the \p Dest module. The
+    /// \p Src module will be destructed or subsumed by this method. In either
+    /// case it is not usable by the caller after this method is invoked. Only
+    /// the \p Dest module will remain. The \p Src module is linked into the
+    /// Linker's composite module such that types, global variables, functions,
+    /// and etc. are matched and resolved.  If an error occurs, this function
+    /// returns true and ErrorMsg is set to a descriptive message about the
+    /// error.
+    /// @returns True if an error occurs, false otherwise.
+    /// @brief Generically link two modules together.
+    static bool LinkModules(Module* Dest, Module* Src, std::string* ErrorMsg);
+
+    /// This function looks through the Linker's LibPaths to find a library with
+    /// the name \p Filename. If the library cannot be found, the returned path
+    /// will be empty (i.e. sys::Path::isEmpty() will return true).
+    /// @returns A sys::Path to the found library
+    /// @brief Find a library from its short name.
+    sys::Path FindLib(const std::string &Filename);
+
+  /// @}
+  /// @name Implementation
+  /// @{
+  private:
+    /// Read in and parse the bitcode file named by FN and return the
+    /// Module it contains (wrapped in an auto_ptr), or 0 if an error occurs.
+    std::auto_ptr<Module> LoadObject(const sys::Path& FN);
+
+    bool warning(const std::string& message);
+    bool error(const std::string& message);
+    void verbose(const std::string& message);
+
+  /// @}
+  /// @name Data
+  /// @{
+  private:
+    Module* Composite; ///< The composite module linked together
+    std::vector<sys::Path> LibPaths; ///< The library search paths
+    unsigned Flags;    ///< Flags to control optional behavior.
+    std::string Error; ///< Text of error that occurred.
+    std::string ProgramName; ///< Name of the program being linked
+  /// @}
+
+};
+
+} // End llvm namespace
+
+#endif