llvm-6502/lib/Linker/LinkArchives.cpp

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//===- lib/Linker/LinkArchives.cpp - Link LLVM objects and libraries ------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains routines to handle linking together LLVM bytecode files,
// and to handle annoying things like static libraries.
//
//===----------------------------------------------------------------------===//
#include "llvm/Linker.h"
#include "llvm/Module.h"
#include "llvm/ModuleProvider.h"
#include "llvm/PassManager.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/Archive.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Config/config.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/Timer.h"
#include "llvm/System/Signals.h"
#include "llvm/Support/SystemUtils.h"
#include <algorithm>
#include <fstream>
#include <memory>
#include <set>
using namespace llvm;
/// FindLib - Try to convert Filename into the name of a file that we can open,
/// if it does not already name a file we can open, by first trying to open
/// Filename, then libFilename.[suffix] for each of a set of several common
/// library suffixes, in each of the directories in Paths and the directory
/// named by the value of the environment variable LLVM_LIB_SEARCH_PATH. Returns
/// an empty string if no matching file can be found.
///
std::string llvm::FindLib(const std::string &Filename,
const std::vector<std::string> &Paths,
bool SharedObjectOnly) {
// Determine if the pathname can be found as it stands.
if (FileOpenable(Filename))
return Filename;
// If that doesn't work, convert the name into a library name.
std::string LibName = "lib" + Filename;
// Iterate over the directories in Paths to see if we can find the library
// there.
for (unsigned Index = 0; Index != Paths.size(); ++Index) {
std::string Directory = Paths[Index] + "/";
if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".bca"))
return Directory + LibName + ".bca";
if (FileOpenable(Directory + LibName + LTDL_SHLIB_EXT))
return Directory + LibName + LTDL_SHLIB_EXT;
if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".a"))
return Directory + LibName + ".a";
}
// One last hope: Check LLVM_LIB_SEARCH_PATH.
char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
if (SearchPath == NULL)
return std::string();
LibName = std::string(SearchPath) + "/" + LibName;
if (FileOpenable(LibName))
return LibName;
return std::string();
}
/// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the
/// name of each externally-visible symbol defined in M.
///
void llvm::GetAllDefinedSymbols(Module *M,
std::set<std::string> &DefinedSymbols) {
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
/// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
/// exist in an LLVM module. This is a bit tricky because there may be two
/// symbols with the same name but different LLVM types that will be resolved to
/// each other but aren't currently (thus we need to treat it as resolved).
///
/// Inputs:
/// M - The module in which to find undefined symbols.
///
/// Outputs:
/// UndefinedSymbols - A set of C++ strings containing the name of all
/// undefined symbols.
///
void
llvm::GetAllUndefinedSymbols(Module *M,
std::set<std::string> &UndefinedSymbols) {
std::set<std::string> DefinedSymbols;
UndefinedSymbols.clear();
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
if (I->hasName()) {
if (I->isExternal())
UndefinedSymbols.insert(I->getName());
else if (!I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
if (I->hasName()) {
if (I->isExternal())
UndefinedSymbols.insert(I->getName());
else if (!I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
// Prune out any defined symbols from the undefined symbols set...
for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
I != UndefinedSymbols.end(); )
if (DefinedSymbols.count(*I))
UndefinedSymbols.erase(I++); // This symbol really is defined!
else
++I; // Keep this symbol in the undefined symbols list
}
/// LoadObject - Read in and parse the bytecode file named by FN and return the
/// module it contains (wrapped in an auto_ptr), or 0 and set ErrorMessage if an
/// error occurs.
///
static std::auto_ptr<Module> LoadObject(const std::string &FN,
std::string &ErrorMessage) {
std::string ParserErrorMessage;
Module *Result = ParseBytecodeFile(FN, &ParserErrorMessage);
if (Result) return std::auto_ptr<Module>(Result);
ErrorMessage = "Bytecode file '" + FN + "' could not be loaded";
if (ParserErrorMessage.size()) ErrorMessage += ": " + ParserErrorMessage;
return std::auto_ptr<Module>();
}
/// LinkInArchive - opens an archive library and link in all objects which
/// provide symbols that are currently undefined.
///
/// Inputs:
/// M - The module in which to link the archives.
/// Filename - The pathname of the archive.
/// Verbose - Flags whether verbose messages should be printed.
///
/// Outputs:
/// ErrorMessage - A C++ string detailing what error occurred, if any.
///
/// Return Value:
/// TRUE - An error occurred.
/// FALSE - No errors.
///
bool llvm::LinkInArchive(Module *M,
const std::string &Filename,
std::string* ErrorMessage,
bool Verbose)
{
// Find all of the symbols currently undefined in the bytecode program.
// If all the symbols are defined, the program is complete, and there is
// no reason to link in any archive files.
std::set<std::string> UndefinedSymbols;
GetAllUndefinedSymbols(M, UndefinedSymbols);
if (UndefinedSymbols.empty()) {
if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
return false; // No need to link anything in!
}
// Open the archive file
if (Verbose) std::cerr << " Loading archive file '" << Filename << "'\n";
std::auto_ptr<Archive> AutoArch (
Archive::OpenAndLoadSymbols(sys::Path(Filename)));
Archive* arch = AutoArch.get();
// Save a set of symbols that are not defined by the archive. Since we're
// entering a loop, there's no point searching for these multiple times. This
// variable is used to "set_subtract" from the set of undefined symbols.
std::set<std::string> NotDefinedByArchive;
// While we are linking in object files, loop.
while (true) {
// Find the modules we need to link into the target module
std::set<ModuleProvider*> Modules;
arch->findModulesDefiningSymbols(UndefinedSymbols, Modules);
// If we didn't find any more modules to link this time, we are done
// searching this archive.
if (Modules.empty())
break;
// Any symbols remaining in UndefinedSymbols after
// findModulesDefiningSymbols are ones that the archive does not define. So
// we add them to the NotDefinedByArchive variable now.
NotDefinedByArchive.insert(UndefinedSymbols.begin(),
UndefinedSymbols.end());
// Loop over all the ModuleProviders that we got back from the archive
for (std::set<ModuleProvider*>::iterator I=Modules.begin(), E=Modules.end();
I != E; ++I) {
// Get the module we must link in.
std::auto_ptr<Module> AutoModule( (*I)->releaseModule() );
Module* aModule = AutoModule.get();
// Link it in
if (LinkModules(M, aModule, ErrorMessage))
return true; // Couldn't link in the module
}
// Get the undefined symbols from the aggregate module. This recomputes the
// symbols we still need after the new modules have been linked in.
GetAllUndefinedSymbols(M, UndefinedSymbols);
// At this point we have two sets of undefined symbols: UndefinedSymbols
// which holds the undefined symbols from all the modules, and
// NotDefinedByArchive which holds symbols we know the archive doesn't
// define. There's no point searching for symbols that we won't find in the
// archive so we subtract these sets.
set_subtract<std::set<std::string>,std::set<std::string> >(
UndefinedSymbols,NotDefinedByArchive);
// If there's no symbols left, no point in continuing to search the
// archive.
if (UndefinedSymbols.empty())
break;
}
return false;
}
/// LinkInFile - opens a bytecode file and links in all objects which
/// provide symbols that are currently undefined.
///
/// Inputs:
/// HeadModule - The module in which to link the bytecode file.
/// Filename - The pathname of the bytecode file.
/// Verbose - Flags whether verbose messages should be printed.
///
/// Outputs:
/// ErrorMessage - A C++ string detailing what error occurred, if any.
///
/// Return Value:
/// TRUE - An error occurred.
/// FALSE - No errors.
///
static bool LinkInFile(Module *HeadModule,
const std::string &Filename,
std::string &ErrorMessage,
bool Verbose)
{
std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage));
if (M.get() == 0) return true;
bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage);
if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n";
return Result;
}
/// LinkFiles - takes a module and a list of files and links them all together.
/// It locates the file either in the current directory, as its absolute
/// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
///
/// Inputs:
/// progname - The name of the program (infamous argv[0]).
/// HeadModule - The module under which all files will be linked.
/// Files - A vector of C++ strings indicating the LLVM bytecode filenames
/// to be linked. The names can refer to a mixture of pure LLVM
/// bytecode files and archive (ar) formatted files.
/// Verbose - Flags whether verbose output should be printed while linking.
///
/// Outputs:
/// HeadModule - The module will have the specified LLVM bytecode files linked
/// in.
///
/// Return value:
/// FALSE - No errors.
/// TRUE - Some error occurred.
///
bool llvm::LinkFiles(const char *progname, Module *HeadModule,
const std::vector<std::string> &Files, bool Verbose) {
// String in which to receive error messages.
std::string ErrorMessage;
// Full pathname of the file
std::string Pathname;
// Get the library search path from the environment
char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
for (unsigned i = 0; i < Files.size(); ++i) {
// Determine where this file lives.
if (FileOpenable(Files[i])) {
Pathname = Files[i];
} else {
if (SearchPath == NULL) {
std::cerr << progname << ": Cannot find linker input file '"
<< Files[i] << "'\n";
std::cerr << progname
<< ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n";
return true;
}
Pathname = std::string(SearchPath)+"/"+Files[i];
if (!FileOpenable(Pathname)) {
std::cerr << progname << ": Cannot find linker input file '"
<< Files[i] << "'\n";
return true;
}
}
// A user may specify an ar archive without -l, perhaps because it
// is not installed as a library. Detect that and link the library.
if (IsArchive(Pathname)) {
if (Verbose)
std::cerr << "Trying to link archive '" << Pathname << "'\n";
if (LinkInArchive(HeadModule, Pathname, &ErrorMessage, Verbose)) {
std::cerr << progname << ": Error linking in archive '" << Pathname
<< "': " << ErrorMessage << "\n";
return true;
}
} else if (IsBytecode(Pathname)) {
if (Verbose)
std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
std::cerr << progname << ": Error linking in bytecode file '"
<< Pathname << "': " << ErrorMessage << "\n";
return true;
}
} else {
std::cerr << progname << ": Warning: invalid file `" << Pathname
<< "' ignored.\n";
}
}
return false;
}
/// LinkOneLibrary - links one library of any kind into the HeadModule
static inline void LinkOneLibrary(const char*progname, Module* HeadModule,
const std::string& Lib,
const std::vector<std::string>& LibPaths,
bool Verbose, bool Native) {
// String in which to receive error messages.
std::string ErrorMessage;
// Determine where this library lives.
std::string Pathname = FindLib(Lib, LibPaths);
if (Pathname.empty()) {
// If the pathname does not exist, then simply return if we're doing a
// native link and give a warning if we're doing a bytecode link.
if (!Native) {
std::cerr << progname << ": WARNING: Cannot find library -l"
<< Lib << "\n";
return;
}
}
// A user may specify an ar archive without -l, perhaps because it
// is not installed as a library. Detect that and link the library.
if (IsArchive(Pathname)) {
if (Verbose)
std::cerr << "Trying to link archive '" << Pathname << "' (-l"
<< Lib << ")\n";
if (LinkInArchive(HeadModule, Pathname, &ErrorMessage, Verbose)) {
std::cerr << progname << ": " << ErrorMessage
<< ": Error linking in archive '" << Pathname << "' (-l"
<< Lib << ")\n";
exit(1);
}
} else {
std::cerr << progname << ": WARNING: Supposed library -l"
<< Lib << " isn't a library.\n";
}
}
/// LinkLibraries - takes the specified library files and links them into the
/// main bytecode object file.
///
/// Inputs:
/// progname - The name of the program (infamous argv[0]).
/// HeadModule - The module into which all necessary libraries will be linked.
/// Libraries - The list of libraries to link into the module.
/// LibPaths - The list of library paths in which to find libraries.
/// Verbose - Flags whether verbose messages should be printed.
/// Native - Flags whether native code is being generated.
///
/// Outputs:
/// HeadModule - The module will have all necessary libraries linked in.
///
/// Return value:
/// FALSE - No error.
/// TRUE - Error.
///
void llvm::LinkLibraries(const char *progname, Module *HeadModule,
const std::vector<std::string> &Libraries,
const std::vector<std::string> &LibPaths,
bool Verbose, bool Native) {
// Process the set of libraries we've been provided
for (unsigned i = 0; i < Libraries.size(); ++i) {
LinkOneLibrary(progname,HeadModule,Libraries[i],LibPaths,Verbose,Native);
}
// At this point we have processed all the libraries provided to us. Since
// we have an aggregated module at this point, the dependent libraries in
// that module should also be aggregated with duplicates eliminated. This is
// now the time to process the dependent libraries to resolve any remaining
// symbols.
const Module::LibraryListType& DepLibs = HeadModule->getLibraries();
for (Module::LibraryListType::const_iterator I = DepLibs.begin(),
E = DepLibs.end(); I != E; ++I) {
LinkOneLibrary(progname,HeadModule,*I,LibPaths,Verbose,Native);
}
}