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//===- lib/Linker/LinkItems.cpp - Link LLVM objects and libraries ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains routines to handle linking together LLVM bitcode files,
// and to handle annoying things like static libraries.
//
//===----------------------------------------------------------------------===//
#include "llvm/Linker.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/system_error.h"
using namespace llvm;
// LinkItems - This function is the main entry point into linking. It takes a
// list of LinkItem which indicates the order the files should be linked and
// how each file should be treated (plain file or with library search). The
// function only links bitcode and produces a result list of items that are
// native objects.
bool
Linker::LinkInItems(const ItemList& Items, ItemList& NativeItems) {
// Clear the NativeItems just in case
NativeItems.clear();
// For each linkage item ...
for (ItemList::const_iterator I = Items.begin(), E = Items.end();
I != E; ++I) {
if (I->second) {
// Link in the library suggested.
bool is_native = false;
if (LinkInLibrary(I->first, is_native))
return true;
if (is_native)
NativeItems.push_back(*I);
} else {
// Link in the file suggested
bool is_native = false;
if (LinkInFile(sys::Path(I->first), is_native))
return true;
if (is_native)
NativeItems.push_back(*I);
}
}
return false;
}
/// LinkInLibrary - links one library into the HeadModule.
///
bool Linker::LinkInLibrary(StringRef Lib, bool& is_native) {
is_native = false;
// Determine where this library lives.
sys::Path Pathname = FindLib(Lib);
if (Pathname.isEmpty())
return error("Cannot find library '" + Lib.str() + "'");
// If its an archive, try to link it in
std::string Magic;
Pathname.getMagicNumber(Magic, 64);
switch (sys::IdentifyFileType(Magic.c_str(), 64)) {
default: llvm_unreachable("Bad file type identification");
case sys::Unknown_FileType:
return warning("Supposed library '" + Lib.str() + "' isn't a library.");
case sys::Bitcode_FileType:
// LLVM ".so" file.
if (LinkInFile(Pathname, is_native))
return true;
break;
case sys::Archive_FileType:
if (LinkInArchive(Pathname, is_native))
return error("Cannot link archive '" + Pathname.str() + "'");
break;
case sys::ELF_Relocatable_FileType:
case sys::ELF_SharedObject_FileType:
case sys::Mach_O_Object_FileType:
case sys::Mach_O_FixedVirtualMemorySharedLib_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLib_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLibStub_FileType:
case sys::COFF_FileType:
is_native = true;
break;
}
return false;
}
/// LinkLibraries - takes the specified library files and links them into the
/// main bitcode object file.
///
/// Inputs:
/// Libraries - The list of libraries to link into the module.
///
/// Return value:
/// FALSE - No error.
/// TRUE - Error.
///
bool Linker::LinkInLibraries(const std::vector<std::string> &Libraries) {
// Process the set of libraries we've been provided.
bool is_native = false;
for (unsigned i = 0; i < Libraries.size(); ++i)
if (LinkInLibrary(Libraries[i], is_native))
return true;
return false;
}
/// LinkInFile - opens a bitcode file and links in all objects which
/// provide symbols that are currently undefined.
///
/// Inputs:
/// File - The pathname of the bitcode file.
///
/// Outputs:
/// ErrorMessage - A C++ string detailing what error occurred, if any.
///
/// Return Value:
/// TRUE - An error occurred.
/// FALSE - No errors.
///
bool Linker::LinkInFile(const sys::Path &File, bool &is_native) {
is_native = false;
// Check for a file of name "-", which means "read standard input"
if (File.str() == "-") {
std::auto_ptr<Module> M;
OwningPtr<MemoryBuffer> Buffer;
error_code ec;
if (!(ec = MemoryBuffer::getSTDIN(Buffer))) {
if (!Buffer->getBufferSize()) {
Error = "standard input is empty";
} else {
M.reset(ParseBitcodeFile(Buffer.get(), Context, &Error));
if (M.get())
if (!LinkInModule(M.get(), &Error))
return false;
}
}
return error("Cannot link stdin: " + ec.message());
}
// Determine what variety of file it is.
std::string Magic;
if (!File.getMagicNumber(Magic, 64))
return error("Cannot find linker input '" + File.str() + "'");
switch (sys::IdentifyFileType(Magic.c_str(), 64)) {
default: llvm_unreachable("Bad file type identification");
case sys::Unknown_FileType:
return warning("Ignoring file '" + File.str() +
"' because does not contain bitcode.");
case sys::Archive_FileType:
// A user may specify an ar archive without -l, perhaps because it
// is not installed as a library. Detect that and link the archive.
if (LinkInArchive(File, is_native))
return true;
break;
case sys::Bitcode_FileType: {
verbose("Linking bitcode file '" + File.str() + "'");
std::auto_ptr<Module> M(LoadObject(File));
if (M.get() == 0)
return error("Cannot load file '" + File.str() + "': " + Error);
if (LinkInModule(M.get(), &Error))
return error("Cannot link file '" + File.str() + "': " + Error);
verbose("Linked in file '" + File.str() + "'");
break;
}
case sys::ELF_Relocatable_FileType:
case sys::ELF_SharedObject_FileType:
case sys::Mach_O_Object_FileType:
case sys::Mach_O_FixedVirtualMemorySharedLib_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLib_FileType:
case sys::Mach_O_DynamicallyLinkedSharedLibStub_FileType:
case sys::COFF_FileType:
is_native = true;
break;
}
return false;
}
/// 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:
/// Files - A vector of sys::Path indicating the LLVM bitcode filenames
/// to be linked. The names can refer to a mixture of pure LLVM
/// bitcode files and archive (ar) formatted files.
///
/// Return value:
/// FALSE - No errors.
/// TRUE - Some error occurred.
///
bool Linker::LinkInFiles(const std::vector<sys::Path> &Files) {
bool is_native;
for (unsigned i = 0; i < Files.size(); ++i)
if (LinkInFile(Files[i], is_native))
return true;
return false;
}
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