[llvm-commits] CVS: llvm/include/llvm/Linker.h

Reid Spencer reid at x10sys.com
Sun Dec 12 18:58:15 PST 2004



Changes in directory llvm/include/llvm:

Linker.h updated: 1.13 -> 1.14
---
Log message:

Completely rewrite the interface to be class based

---
Diffs of the changes:  (+259 -107)

Index: llvm/include/llvm/Linker.h
diff -u llvm/include/llvm/Linker.h:1.13 llvm/include/llvm/Linker.h:1.14
--- llvm/include/llvm/Linker.h:1.13	Sun Dec  5 13:14:43 2004
+++ llvm/include/llvm/Linker.h	Sun Dec 12 20:58:05 2004
@@ -14,120 +14,272 @@
 #ifndef LLVM_LINKER_H
 #define LLVM_LINKER_H
 
-#include "llvm/Support/CommandLine.h"
-#include <string>
+#include "llvm/System/Path.h"
 #include <vector>
-#include <set>
 
 namespace llvm {
 
 class Module;
 
-/// 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, false for files, signifying "isLibrary".
-/// @brief A list of string/bool pairs
-typedef std::vector<std::pair<std::string,bool> > LinkItemList;
-
-/// This function can be used to link a set of linkage items into a module. A
-/// linkage item is one of the three things identified by the LinkItemKind
-/// enumeration. This function allows linking to preserve the order of 
-/// specification associated with a command line, or for other purposes. Each
-/// item will be linked in turn as it occurs in \p Items. Note that library
-/// path items will only be in effect after they have been processed.
-/// @returns The aggregated/linked Module.
-/// @throws nothing
-Module* LinkItems (
-  const char * progname,   ///< Name of the program being linked (for output)
-  const LinkItemList& Items, // Set of libraries/files to link in
-  const std::vector<std::string>& LibPaths, // Paths to search for libraries
-  bool Verbose, ///< Link verbosely, indicating each action
-  bool Native ///< Linking is for a native executable
-);
-
-/// This function provides some utility for tools that need to build the list
-/// of link items from a triplet of command line options: Files, Libraries, and
-/// LibraryPaths. The command line ordering is preserved by this function even
-/// though the options are split into three separate cl::list<std::string>. The
-/// resulting \p OutList is suitable for use with LinkItems.
-/// @see LinkItems
-/// @throws nothing
-void BuildLinkItems(
-  LinkItemList& OutList,
-  const cl::list<std::string>& Files, ///< List of files to put in list
-  const cl::list<std::string>& Libs   ///< List of libraries to put in list
-);
-
-/// This is the heart of the linker. The \p Src module is linked into the \p
-/// Dest module. If an error occurs, true is returned, otherwise false. If \p
-/// ErrorMsg is not null and an error occurs, \p *ErrorMsg will be set to a
-/// readable string that indicates the nature of the error.  Note that this can
-/// destroy the Src module in arbitrary ways.
-///
-/// @returns true if there's an error
-/// @brief Link two modules together
-bool LinkModules(
-  Module* Dest,          ///< Module into which \p Src is linked
-  Module* Src,     ///< Module linked into \p Dest
-  std::string* ErrorMsg  ///< Optional error message string
-);
-
-/// This function links the bytecode \p Files into the \p HeadModule. 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 bytecode file and calls LinkModules on them. 
-/// @returns true if an error occurs, false otherwise
-bool LinkFiles (
-  const char * progname, ///< Name of the program being linked (for output)
-  Module * HeadModule,   ///< Main (resulting) module to be linked into
-  const std::vector<std::string> & Files, ///< Files to link in
-  bool Verbose ///< Link verbosely, indicating each action
-);
-
-/// This function links one archive, \p Filename,  that contains bytecode into
-/// \p HeadModule.  If an error occurs, true is returned, otherwise false. If
-/// \p ErrorMsg is not null and an error occurs, \p *ErrorMsg will be set to a
-/// readable string that indicates the nature of the error.
-/// @returns true if there's an error
-/// @brief Link in one archive.
-bool LinkInArchive( 
-  Module* HeadModule,          ///< Main (resulting) module to be linked into
-  const std::string& Filename, ///< Filename of the archive to link
-  std::string* ErrorMsg,       ///< Error message if an error occurs.
-  bool Verbose                 ///< Link verbosely, indicating each action
-);
-
-/// This function provides the ability to handle the -L and -l options on a 
-/// linker's command line. It will link into \p HeadModule any modules found in
-/// the \p Libraries (which might be found in the \p LibPaths). 
-/// @brief Link libraries into a module
-void LinkLibraries (
-  const char * progname,   ///< Name of the program being linked (for output)
-  Module* HeadModule,      ///< Main (resulting) module to be linked into
-  const std::vector<std::string> & Libraries, ///< Set of libraries to link in
-  const std::vector<std::string> & LibPaths,  ///< Set of library paths
-  bool Verbose, ///< Link verbosely, indicating each action
-  bool Native ///< Linking is for a native executable
-);
-
-/// This function looks at Module \p M and returns a set of strings, 
-/// \p DefinedSymbols, that is the publicly visible defined symbols in 
-/// module \p M.
-void GetAllDefinedSymbols (Module *M, std::set<std::string> &DefinedSymbols);
-
-/// This function looks at Module \p M and returns a set of strings, 
-/// \p UnefinedSymbols, that is the publicly visible undefined symbols in 
-/// module \p M.
-void GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols);
-
-/// This function looks through a set of \p Paths to find a library with the
-/// name \p Filename. If \p SharedObjectOnly is true, it only finds a match
-/// if the file is a shared library.
-std::string FindLib(const std::string &Filename,
-                    const std::vector<std::string> &Paths,
-                    bool SharedObjectOnly = false);
+/// 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, bytecode files, or bytecode 
+/// 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 errors and warnings to std::cerr.
+      QuietErrors   = 4, ///< Indicate that this link is for a native executable
+    };
+
+  /// @}
+  /// @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, unsigned Flags = 0 );
+
+    /// 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
+    );
+
+    /// This function links the bytecode \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 bytecode 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 bytecode file, \p File, into the composite
+    /// module. Note that this does not attempt to resolve symbols. This method
+    /// just loads the bytecode 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.
+    );
+
+    /// 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
+    );
+
+    /// This function links one bytecode 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
+    );
+
+    /// 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
+    ) { return LinkModules(Composite, Src, &Error); }
+
+    /// 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 bytecode 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






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