mirror of
https://github.com/c64scene-ar/llvm-6502.git
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0ebee7410f
to reduce the inter-file interface in the gccld tool and gets some uninteresting code out of gccld.cpp. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13942 91177308-0d34-0410-b5e6-96231b3b80d8
420 lines
15 KiB
C++
420 lines
15 KiB
C++
//===- Linker.cpp - Link together LLVM objects and libraries --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains routines to handle linking together LLVM bytecode files,
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// and to handle annoying things like static libraries.
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//
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//===----------------------------------------------------------------------===//
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#include "gccld.h"
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#include "llvm/Module.h"
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#include "llvm/PassManager.h"
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#include "llvm/Bytecode/Reader.h"
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#include "llvm/Bytecode/WriteBytecodePass.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/Linker.h"
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#include "Config/config.h"
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#include "Support/CommandLine.h"
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#include "Support/FileUtilities.h"
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#include "llvm/System/Signals.h"
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#include "Support/SystemUtils.h"
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#include <algorithm>
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#include <fstream>
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#include <memory>
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#include <set>
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using namespace llvm;
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/// FindLib - Try to convert Filename into the name of a file that we can open,
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/// if it does not already name a file we can open, by first trying to open
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/// Filename, then libFilename.[suffix] for each of a set of several common
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/// library suffixes, in each of the directories in Paths and the directory
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/// named by the value of the environment variable LLVM_LIB_SEARCH_PATH. Returns
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/// an empty string if no matching file can be found.
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///
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std::string llvm::FindLib(const std::string &Filename,
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const std::vector<std::string> &Paths,
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bool SharedObjectOnly) {
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// Determine if the pathname can be found as it stands.
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if (FileOpenable(Filename))
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return Filename;
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// If that doesn't work, convert the name into a library name.
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std::string LibName = "lib" + Filename;
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// Iterate over the directories in Paths to see if we can find the library
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// there.
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for (unsigned Index = 0; Index != Paths.size(); ++Index) {
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std::string Directory = Paths[Index] + "/";
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if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".bc"))
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return Directory + LibName + ".bc";
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if (FileOpenable(Directory + LibName + SHLIBEXT))
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return Directory + LibName + SHLIBEXT;
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if (!SharedObjectOnly && FileOpenable(Directory + LibName + ".a"))
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return Directory + LibName + ".a";
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}
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// One last hope: Check LLVM_LIB_SEARCH_PATH.
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char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
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if (SearchPath == NULL)
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return std::string();
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LibName = std::string(SearchPath) + "/" + LibName;
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if (FileOpenable(LibName))
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return LibName;
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return std::string();
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}
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/// GetAllDefinedSymbols - Modifies its parameter DefinedSymbols to contain the
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/// name of each externally-visible symbol defined in M.
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///
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void llvm::GetAllDefinedSymbols(Module *M,
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std::set<std::string> &DefinedSymbols) {
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for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
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if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
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if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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/// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
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/// exist in an LLVM module. This is a bit tricky because there may be two
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/// symbols with the same name but different LLVM types that will be resolved to
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/// each other but aren't currently (thus we need to treat it as resolved).
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///
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/// Inputs:
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/// M - The module in which to find undefined symbols.
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///
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/// Outputs:
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/// UndefinedSymbols - A set of C++ strings containing the name of all
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/// undefined symbols.
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///
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void
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llvm::GetAllUndefinedSymbols(Module *M,
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std::set<std::string> &UndefinedSymbols) {
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std::set<std::string> DefinedSymbols;
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UndefinedSymbols.clear(); // Start out empty
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for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
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if (I->hasName()) {
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if (I->isExternal())
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UndefinedSymbols.insert(I->getName());
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else if (!I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
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if (I->hasName()) {
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if (I->isExternal())
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UndefinedSymbols.insert(I->getName());
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else if (!I->hasInternalLinkage())
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DefinedSymbols.insert(I->getName());
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}
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// Prune out any defined symbols from the undefined symbols set...
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for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
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I != UndefinedSymbols.end(); )
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if (DefinedSymbols.count(*I))
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UndefinedSymbols.erase(I++); // This symbol really is defined!
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else
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++I; // Keep this symbol in the undefined symbols list
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}
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/// LoadObject - Read in and parse the bytecode file named by FN and return the
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/// module it contains (wrapped in an auto_ptr), or 0 and set ErrorMessage if an
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/// error occurs.
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///
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std::auto_ptr<Module> llvm::LoadObject(const std::string &FN,
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std::string &ErrorMessage) {
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std::string ParserErrorMessage;
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Module *Result = ParseBytecodeFile(FN, &ParserErrorMessage);
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if (Result) return std::auto_ptr<Module>(Result);
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ErrorMessage = "Bytecode file '" + FN + "' could not be loaded";
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if (ParserErrorMessage.size()) ErrorMessage += ": " + ParserErrorMessage;
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return std::auto_ptr<Module>();
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}
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/// LinkInArchive - opens an archive library and link in all objects which
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/// provide symbols that are currently undefined.
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///
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/// Inputs:
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/// M - The module in which to link the archives.
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/// Filename - The pathname of the archive.
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/// Verbose - Flags whether verbose messages should be printed.
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///
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/// Outputs:
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/// ErrorMessage - A C++ string detailing what error occurred, if any.
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///
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/// Return Value:
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/// TRUE - An error occurred.
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/// FALSE - No errors.
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///
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static bool LinkInArchive(Module *M,
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const std::string &Filename,
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std::string &ErrorMessage,
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bool Verbose)
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{
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// Find all of the symbols currently undefined in the bytecode program.
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// If all the symbols are defined, the program is complete, and there is
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// no reason to link in any archive files.
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std::set<std::string> UndefinedSymbols;
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GetAllUndefinedSymbols(M, UndefinedSymbols);
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if (UndefinedSymbols.empty()) {
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if (Verbose) std::cerr << " No symbols undefined, don't link library!\n";
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return false; // No need to link anything in!
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}
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// Load in the archive objects.
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if (Verbose) std::cerr << " Loading archive file '" << Filename << "'\n";
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std::vector<Module*> Objects;
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if (ReadArchiveFile(Filename, Objects, &ErrorMessage))
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return true;
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// Figure out which symbols are defined by all of the modules in the archive.
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std::vector<std::set<std::string> > DefinedSymbols;
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DefinedSymbols.resize(Objects.size());
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for (unsigned i = 0; i != Objects.size(); ++i) {
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GetAllDefinedSymbols(Objects[i], DefinedSymbols[i]);
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}
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// While we are linking in object files, loop.
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bool Linked = true;
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while (Linked) {
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Linked = false;
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for (unsigned i = 0; i != Objects.size(); ++i) {
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// Consider whether we need to link in this module... we only need to
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// link it in if it defines some symbol which is so far undefined.
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//
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const std::set<std::string> &DefSymbols = DefinedSymbols[i];
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bool ObjectRequired = false;
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//
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// If the object defines main() and the program currently has main()
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// undefined, then automatically link in the module. Otherwise, look to
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// see if it defines a symbol that is currently undefined.
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//
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if ((M->getMainFunction() == NULL) &&
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((DefSymbols.find ("main")) != DefSymbols.end())) {
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ObjectRequired = true;
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} else {
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for (std::set<std::string>::iterator I = UndefinedSymbols.begin(),
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E = UndefinedSymbols.end(); I != E; ++I)
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if (DefSymbols.count(*I)) {
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if (Verbose)
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std::cerr << " Found object '"
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<< Objects[i]->getModuleIdentifier ()
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<< "' providing symbol '" << *I << "'...\n";
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ObjectRequired = true;
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break;
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}
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}
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// We DO need to link this object into the program...
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if (ObjectRequired) {
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if (LinkModules(M, Objects[i], &ErrorMessage))
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return true; // Couldn't link in the right object file...
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// Since we have linked in this object, delete it from the list of
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// objects to consider in this archive file.
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std::swap(Objects[i], Objects.back());
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std::swap(DefinedSymbols[i], DefinedSymbols.back());
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Objects.pop_back();
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DefinedSymbols.pop_back();
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--i; // Do not skip an entry
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// The undefined symbols set should have shrunk.
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GetAllUndefinedSymbols(M, UndefinedSymbols);
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Linked = true; // We have linked something in!
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}
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}
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}
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return false;
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}
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/// LinkInFile - opens a bytecode file and links in all objects which
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/// provide symbols that are currently undefined.
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///
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/// Inputs:
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/// HeadModule - The module in which to link the bytecode file.
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/// Filename - The pathname of the bytecode file.
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/// Verbose - Flags whether verbose messages should be printed.
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///
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/// Outputs:
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/// ErrorMessage - A C++ string detailing what error occurred, if any.
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///
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/// Return Value:
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/// TRUE - An error occurred.
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/// FALSE - No errors.
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///
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static bool LinkInFile(Module *HeadModule,
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const std::string &Filename,
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std::string &ErrorMessage,
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bool Verbose)
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{
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std::auto_ptr<Module> M(LoadObject(Filename, ErrorMessage));
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if (M.get() == 0) return true;
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bool Result = LinkModules(HeadModule, M.get(), &ErrorMessage);
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if (Verbose) std::cerr << "Linked in bytecode file '" << Filename << "'\n";
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return Result;
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}
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/// LinkFiles - takes a module and a list of files and links them all together.
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/// It locates the file either in the current directory, as its absolute
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/// or relative pathname, or as a file somewhere in LLVM_LIB_SEARCH_PATH.
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///
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/// Inputs:
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/// progname - The name of the program (infamous argv[0]).
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/// HeadModule - The module under which all files will be linked.
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/// Files - A vector of C++ strings indicating the LLVM bytecode filenames
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/// to be linked. The names can refer to a mixture of pure LLVM
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/// bytecode files and archive (ar) formatted files.
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/// Verbose - Flags whether verbose output should be printed while linking.
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///
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/// Outputs:
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/// HeadModule - The module will have the specified LLVM bytecode files linked
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/// in.
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///
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/// Return value:
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/// FALSE - No errors.
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/// TRUE - Some error occurred.
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///
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bool llvm::LinkFiles(const char *progname, Module *HeadModule,
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const std::vector<std::string> &Files, bool Verbose) {
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// String in which to receive error messages.
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std::string ErrorMessage;
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// Full pathname of the file
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std::string Pathname;
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// Get the library search path from the environment
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char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH");
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for (unsigned i = 0; i < Files.size(); ++i) {
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// Determine where this file lives.
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if (FileOpenable(Files[i])) {
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Pathname = Files[i];
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} else {
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if (SearchPath == NULL) {
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std::cerr << progname << ": Cannot find linker input file '"
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<< Files[i] << "'\n";
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std::cerr << progname
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<< ": Warning: Your LLVM_LIB_SEARCH_PATH is unset.\n";
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return true;
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}
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Pathname = std::string(SearchPath)+"/"+Files[i];
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if (!FileOpenable(Pathname)) {
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std::cerr << progname << ": Cannot find linker input file '"
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<< Files[i] << "'\n";
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return true;
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}
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}
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// A user may specify an ar archive without -l, perhaps because it
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// is not installed as a library. Detect that and link the library.
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if (IsArchive(Pathname)) {
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if (Verbose)
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std::cerr << "Trying to link archive '" << Pathname << "'\n";
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if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
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std::cerr << progname << ": Error linking in archive '" << Pathname
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<< "': " << ErrorMessage << "\n";
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return true;
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}
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} else if (IsBytecode(Pathname)) {
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if (Verbose)
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std::cerr << "Trying to link bytecode file '" << Pathname << "'\n";
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if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
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std::cerr << progname << ": Error linking in bytecode file '"
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<< Pathname << "': " << ErrorMessage << "\n";
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return true;
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}
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}
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}
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return false;
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}
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/// LinkLibraries - takes the specified library files and links them into the
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/// main bytecode object file.
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///
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/// Inputs:
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/// progname - The name of the program (infamous argv[0]).
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/// HeadModule - The module into which all necessary libraries will be linked.
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/// Libraries - The list of libraries to link into the module.
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/// LibPaths - The list of library paths in which to find libraries.
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/// Verbose - Flags whether verbose messages should be printed.
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/// Native - Flags whether native code is being generated.
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///
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/// Outputs:
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/// HeadModule - The module will have all necessary libraries linked in.
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///
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/// Return value:
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/// FALSE - No error.
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/// TRUE - Error.
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///
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void llvm::LinkLibraries(const char *progname, Module *HeadModule,
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const std::vector<std::string> &Libraries,
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const std::vector<std::string> &LibPaths,
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bool Verbose, bool Native) {
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// String in which to receive error messages.
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std::string ErrorMessage;
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for (unsigned i = 0; i < Libraries.size(); ++i) {
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// Determine where this library lives.
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std::string Pathname = FindLib(Libraries[i], LibPaths);
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if (Pathname.empty()) {
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// If the pathname does not exist, then continue to the next one if
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// we're doing a native link and give an error if we're doing a bytecode
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// link.
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if (!Native) {
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std::cerr << progname << ": WARNING: Cannot find library -l"
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<< Libraries[i] << "\n";
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continue;
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}
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}
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// A user may specify an ar archive without -l, perhaps because it
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// is not installed as a library. Detect that and link the library.
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if (IsArchive(Pathname)) {
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if (Verbose)
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std::cerr << "Trying to link archive '" << Pathname << "' (-l"
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<< Libraries[i] << ")\n";
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if (LinkInArchive(HeadModule, Pathname, ErrorMessage, Verbose)) {
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std::cerr << progname << ": " << ErrorMessage
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<< ": Error linking in archive '" << Pathname << "' (-l"
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<< Libraries[i] << ")\n";
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exit(1);
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}
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} else if (IsBytecode(Pathname)) {
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if (Verbose)
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std::cerr << "Trying to link bytecode file '" << Pathname
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<< "' (-l" << Libraries[i] << ")\n";
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if (LinkInFile(HeadModule, Pathname, ErrorMessage, Verbose)) {
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std::cerr << progname << ": " << ErrorMessage
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<< ": error linking in bytecode file '" << Pathname << "' (-l"
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<< Libraries[i] << ")\n";
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exit(1);
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}
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}
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}
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}
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