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llvm-mirror/include/llvm/Linker.h
Tanya Lattner 0ae574fe2b Make it possible to use the linker without destroying the source module. This is so the source module can be linked to multiple other destination modules. For all that used LinkModules() before, they will continue to destroy the source module as before.
This line, and those below, will be ignored--

M    include/llvm/Linker.h
M    tools/bugpoint/Miscompilation.cpp
M    tools/bugpoint/BugDriver.cpp
M    tools/llvm-link/llvm-link.cpp
M    lib/Linker/LinkModules.cpp

llvm-svn: 141606
2011-10-11 00:24:54 +00:00

306 lines
14 KiB
C++

//===- 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 <memory>
#include <vector>
#include "llvm/ADT/StringRef.h"
namespace llvm {
namespace sys { class Path; }
class Module;
class LLVMContext;
/// 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 stderr 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 stderr what steps the linker is taking
QuietWarnings = 2, ///< Don't print warnings to stderr.
QuietErrors = 4 ///< Don't print errors to stderr.
};
enum LinkerMode {
DestroySource = 0, // Allow source module to be destroyed.
PreserveSource = 1 // Preserve the source module.
};
/// @}
/// @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(StringRef progname, ///< name of tool running linker
StringRef modulename, ///< name of linker's end-result module
LLVMContext &C, ///< Context for global info
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(StringRef 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 stderr.
/// @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
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 (
StringRef 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 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, Linker::DestroySource, 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, unsigned Mode,
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(StringRef 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(StringRef message);
bool error(StringRef message);
void verbose(StringRef message);
/// @}
/// @name Data
/// @{
private:
LLVMContext& Context; ///< The context for global information
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