llvm/tools/llvm-ld/llvm-ld.cpp
Reid Spencer 93f8f55e19 For PR351:
Adjust to interface change for FindExecutable.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18920 91177308-0d34-0410-b5e6-96231b3b80d8
2004-12-13 23:44:23 +00:00

540 lines
19 KiB
C++

//===- llvm-ld.cpp - LLVM 'ld' compatible linker --------------------------===//
//
// 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 utility is intended to be compatible with GCC, and follows standard
// system 'ld' conventions. As such, the default output file is ./a.out.
// Additionally, this program outputs a shell script that is used to invoke LLI
// to execute the program. In this manner, the generated executable (a.out for
// example), is directly executable, whereas the bytecode file actually lives in
// the a.out.bc file generated by this program. Also, Force is on by default.
//
// Note that if someone (or a script) deletes the executable program generated,
// the .bc file will be left around. Considering that this is a temporary hack,
// I'm not too worried about this.
//
//===----------------------------------------------------------------------===//
#include "llvm/Linker.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/Writer.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachineRegistry.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/System/Signals.h"
#include <fstream>
#include <iostream>
#include <memory>
using namespace llvm;
// Input/Output Options
static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
cl::desc("<input bytecode files>"));
static cl::opt<std::string> OutputFilename("o", cl::init("a.out"),
cl::desc("Override output filename"),
cl::value_desc("filename"));
static cl::opt<bool> Verbose("v",
cl::desc("Print information about actions taken"));
static cl::list<std::string> LibPaths("L", cl::Prefix,
cl::desc("Specify a library search path"),
cl::value_desc("directory"));
static cl::list<std::string> Libraries("l", cl::Prefix,
cl::desc("Specify libraries to link to"),
cl::value_desc("library prefix"));
static cl::opt<bool> LinkAsLibrary("link-as-library",
cl::desc("Link the .bc files together as a library, not an executable"));
static cl::alias Relink("r", cl::aliasopt(LinkAsLibrary),
cl::desc("Alias for -link-as-library"));
static cl::opt<const TargetMachineRegistry::Entry*, false, TargetNameParser>
MachineArch("march", cl::desc("Architecture to generate assembly for:"));
static cl::opt<bool> Native("native",
cl::desc("Generate a native binary instead of a shell script"));
static cl::opt<bool>NativeCBE("native-cbe",
cl::desc("Generate a native binary with the C backend and GCC"));
static cl::opt<bool>DisableCompression("disable-compression",cl::init(false),
cl::desc("Disable writing of compressed bytecode files"));
// Compatibility options that are ignored but supported by LD
static cl::opt<std::string> CO3("soname", cl::Hidden,
cl::desc("Compatibility option: ignored"));
static cl::opt<std::string> CO4("version-script", cl::Hidden,
cl::desc("Compatibility option: ignored"));
static cl::opt<bool> CO5("eh-frame-hdr", cl::Hidden,
cl::desc("Compatibility option: ignored"));
static cl::opt<std::string> CO6("h", cl::Hidden,
cl::desc("Compatibility option: ignored"));
/// This is just for convenience so it doesn't have to be passed around
/// everywhere.
static std::string progname;
/// PrintAndReturn - Prints a message to standard error and returns true.
///
/// Inputs:
/// progname - The name of the program (i.e. argv[0]).
/// Message - The message to print to standard error.
///
static int PrintAndReturn(const std::string &Message) {
std::cerr << progname << ": " << Message << "\n";
return 1;
}
/// CopyEnv - This function takes an array of environment variables and makes a
/// copy of it. This copy can then be manipulated any way the caller likes
/// without affecting the process's real environment.
///
/// Inputs:
/// envp - An array of C strings containing an environment.
///
/// Return value:
/// NULL - An error occurred.
///
/// Otherwise, a pointer to a new array of C strings is returned. Every string
/// in the array is a duplicate of the one in the original array (i.e. we do
/// not copy the char *'s from one array to another).
///
static char ** CopyEnv(char ** const envp) {
// Count the number of entries in the old list;
unsigned entries; // The number of entries in the old environment list
for (entries = 0; envp[entries] != NULL; entries++)
/*empty*/;
// Add one more entry for the NULL pointer that ends the list.
++entries;
// If there are no entries at all, just return NULL.
if (entries == 0)
return NULL;
// Allocate a new environment list.
char **newenv = new char* [entries];
if ((newenv = new char* [entries]) == NULL)
return NULL;
// Make a copy of the list. Don't forget the NULL that ends the list.
entries = 0;
while (envp[entries] != NULL) {
newenv[entries] = new char[strlen (envp[entries]) + 1];
strcpy (newenv[entries], envp[entries]);
++entries;
}
newenv[entries] = NULL;
return newenv;
}
/// RemoveEnv - Remove the specified environment variable from the environment
/// array.
///
/// Inputs:
/// name - The name of the variable to remove. It cannot be NULL.
/// envp - The array of environment variables. It cannot be NULL.
///
/// Notes:
/// This is mainly done because functions to remove items from the environment
/// are not available across all platforms. In particular, Solaris does not
/// seem to have an unsetenv() function or a setenv() function (or they are
/// undocumented if they do exist).
///
static void RemoveEnv(const char * name, char ** const envp) {
for (unsigned index=0; envp[index] != NULL; index++) {
// Find the first equals sign in the array and make it an EOS character.
char *p = strchr (envp[index], '=');
if (p == NULL)
continue;
else
*p = '\0';
// Compare the two strings. If they are equal, zap this string.
// Otherwise, restore it.
if (!strcmp(name, envp[index]))
*envp[index] = '\0';
else
*p = '=';
}
return;
}
/// GenerateBytecode - generates a bytecode file from the module provided
void GenerateBytecode(Module* M, const std::string& FileName) {
// Create the output file.
std::ofstream Out(FileName.c_str());
if (!Out.good()) {
PrintAndReturn("error opening '" + FileName + "' for writing!");
return;
}
// Ensure that the bytecode file gets removed from the disk if we get a
// terminating signal.
sys::RemoveFileOnSignal(sys::Path(FileName));
// Write it out
WriteBytecodeToFile(M, Out, !DisableCompression);
// Close the bytecode file.
Out.close();
}
/// GenerateAssembly - generates a native assembly language source file from the
/// specified bytecode file.
///
/// Inputs:
/// InputFilename - The name of the output bytecode file.
/// OutputFilename - The name of the file to generate.
/// llc - The pathname to use for LLC.
/// envp - The environment to use when running LLC.
///
/// Return non-zero value on error.
///
static int GenerateAssembly(const std::string &OutputFilename,
const std::string &InputFilename,
const std::string &llc,
char ** const envp) {
// Run LLC to convert the bytecode file into assembly code.
const char *cmd[6];
cmd[0] = llc.c_str();
cmd[1] = "-f";
cmd[2] = "-o";
cmd[3] = OutputFilename.c_str();
cmd[4] = InputFilename.c_str();
cmd[5] = 0;
return ExecWait(cmd, envp);
}
/// GenerateAssembly - generates a native assembly language source file from the
/// specified bytecode file.
static int GenerateCFile(const std::string &OutputFile,
const std::string &InputFile,
const std::string &llc, char ** const envp) {
// Run LLC to convert the bytecode file into C.
const char *cmd[7];
cmd[0] = llc.c_str();
cmd[1] = "-march=c";
cmd[2] = "-f";
cmd[3] = "-o";
cmd[4] = OutputFile.c_str();
cmd[5] = InputFile.c_str();
cmd[6] = 0;
return ExecWait(cmd, envp);
}
/// GenerateNative - generates a native assembly language source file from the
/// specified assembly source file.
///
/// Inputs:
/// InputFilename - The name of the output bytecode file.
/// OutputFilename - The name of the file to generate.
/// Libraries - The list of libraries with which to link.
/// LibPaths - The list of directories in which to find libraries.
/// gcc - The pathname to use for GGC.
/// envp - A copy of the process's current environment.
///
/// Outputs:
/// None.
///
/// Returns non-zero value on error.
///
static int GenerateNative(const std::string &OutputFilename,
const std::string &InputFilename,
const std::vector<std::string> &Libraries,
const std::vector<std::string> &LibPaths,
const std::string &gcc, char ** const envp) {
// Remove these environment variables from the environment of the
// programs that we will execute. It appears that GCC sets these
// environment variables so that the programs it uses can configure
// themselves identically.
//
// However, when we invoke GCC below, we want it to use its normal
// configuration. Hence, we must sanitize its environment.
char ** clean_env = CopyEnv(envp);
if (clean_env == NULL)
return 1;
RemoveEnv("LIBRARY_PATH", clean_env);
RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
RemoveEnv("GCC_EXEC_PREFIX", clean_env);
RemoveEnv("COMPILER_PATH", clean_env);
RemoveEnv("COLLECT_GCC", clean_env);
std::vector<const char *> cmd;
// Run GCC to assemble and link the program into native code.
//
// Note:
// We can't just assemble and link the file with the system assembler
// and linker because we don't know where to put the _start symbol.
// GCC mysteriously knows how to do it.
cmd.push_back(gcc.c_str());
cmd.push_back("-fno-strict-aliasing");
cmd.push_back("-O3");
cmd.push_back("-o");
cmd.push_back(OutputFilename.c_str());
cmd.push_back(InputFilename.c_str());
// Adding the library paths creates a problem for native generation. If we
// include the search paths from llvmgcc, then we'll be telling normal gcc
// to look inside of llvmgcc's library directories for libraries. This is
// bad because those libraries hold only bytecode files (not native object
// files). In the end, we attempt to link the bytecode libgcc into a native
// program.
#if 0
// Add in the library path options.
for (unsigned index=0; index < LibPaths.size(); index++) {
cmd.push_back("-L");
cmd.push_back(LibPaths[index].c_str());
}
#endif
// Add in the libraries to link.
std::vector<std::string> Libs(Libraries);
for (unsigned index = 0; index < Libs.size(); index++) {
if (Libs[index] != "crtend") {
Libs[index] = "-l" + Libs[index];
cmd.push_back(Libs[index].c_str());
}
}
cmd.push_back(NULL);
// Run the compiler to assembly and link together the program.
return ExecWait(&(cmd[0]), clean_env);
}
/// EmitShellScript - Output the wrapper file that invokes the JIT on the LLVM
/// bytecode file for the program.
static void EmitShellScript(char **argv) {
#if defined(_WIN32) || defined(__CYGWIN__)
// Windows doesn't support #!/bin/sh style shell scripts in .exe files. To
// support windows systems, we copy the llvm-stub.exe executable from the
// build tree to the destination file.
std::string llvmstub = FindExecutable("llvm-stub.exe", argv[0]);
if (llvmstub.empty()) {
std::cerr << "Could not find llvm-stub.exe executable!\n";
exit(1);
}
if (CopyFile(OutputFilename, llvmstub)) {
std::cerr << "Could not copy the llvm-stub.exe executable!\n";
exit(1);
}
return;
#endif
// Output the script to start the program...
std::ofstream Out2(OutputFilename.c_str());
if (!Out2.good())
exit(PrintAndReturn("error opening '" + OutputFilename + "' for writing!"));
Out2 << "#!/bin/sh\n";
// Allow user to setenv LLVMINTERP if lli is not in their PATH.
Out2 << "lli=${LLVMINTERP-lli}\n";
Out2 << "exec $lli \\\n";
// gcc accepts -l<lib> and implicitly searches /lib and /usr/lib.
LibPaths.push_back("/lib");
LibPaths.push_back("/usr/lib");
LibPaths.push_back("/usr/X11R6/lib");
// We don't need to link in libc! In fact, /usr/lib/libc.so may not be a
// shared object at all! See RH 8: plain text.
std::vector<std::string>::iterator libc =
std::find(Libraries.begin(), Libraries.end(), "c");
if (libc != Libraries.end()) Libraries.erase(libc);
// List all the shared object (native) libraries this executable will need
// on the command line, so that we don't have to do this manually!
for (std::vector<std::string>::iterator i = Libraries.begin(),
e = Libraries.end(); i != e; ++i) {
sys::Path FullLibraryPath = sys::Path::FindLibrary(*i);
if (!FullLibraryPath.isEmpty() && FullLibraryPath.isDynamicLibrary())
Out2 << " -load=" << FullLibraryPath.toString() << " \\\n";
}
Out2 << " $0.bc ${1+\"$@\"}\n";
Out2.close();
}
// BuildLinkItems -- This function generates a LinkItemList for the LinkItems
// linker function by combining the Files and Libraries in the order they were
// declared on the command line.
static void BuildLinkItems(
Linker::ItemList& Items,
const cl::list<std::string>& Files,
const cl::list<std::string>& Libraries) {
// Build the list of linkage items for LinkItems.
cl::list<std::string>::const_iterator fileIt = Files.begin();
cl::list<std::string>::const_iterator libIt = Libraries.begin();
int libPos = -1, filePos = -1;
while ( libIt != Libraries.end() || fileIt != Files.end() ) {
if (libIt != Libraries.end())
libPos = Libraries.getPosition(libIt - Libraries.begin());
else
libPos = -1;
if (fileIt != Files.end())
filePos = Files.getPosition(fileIt - Files.begin());
else
filePos = -1;
if (filePos != -1 && (libPos == -1 || filePos < libPos)) {
// Add a source file
Items.push_back(std::make_pair(*fileIt++, false));
} else if (libPos != -1 && (filePos == -1 || libPos < filePos)) {
// Add a library
Items.push_back(std::make_pair(*libIt++, true));
}
}
}
// Rightly this should go in a header file but it just seems such a waste.
namespace llvm {
extern void Optimize(Module*);
}
int main(int argc, char **argv, char **envp) {
// Initial global variable above for convenience printing of program name.
progname = sys::Path(argv[0]).getBasename();
Linker TheLinker(progname, Verbose);
// Set up the library paths for the Linker
TheLinker.addPaths(LibPaths);
TheLinker.addSystemPaths();
// Parse the command line options
cl::ParseCommandLineOptions(argc, argv, " llvm linker\n");
sys::PrintStackTraceOnErrorSignal();
// Remove any consecutive duplicates of the same library...
Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
Libraries.end());
if (LinkAsLibrary) {
std::vector<sys::Path> Files;
for (unsigned i = 0; i < InputFilenames.size(); ++i )
Files.push_back(sys::Path(InputFilenames[i]));
if (TheLinker.LinkInFiles(Files))
return 1; // Error already printed
// The libraries aren't linked in but are noted as "dependent" in the
// module.
for (cl::list<std::string>::const_iterator I = Libraries.begin(),
E = Libraries.end(); I != E ; ++I) {
TheLinker.getModule()->addLibrary(*I);
}
} else {
// Build a list of the items from our command line
Linker::ItemList Items;
BuildLinkItems(Items, InputFilenames, Libraries);
// Link all the items together
if (TheLinker.LinkInItems(Items) )
return 1;
}
std::auto_ptr<Module> Composite(TheLinker.releaseModule());
// Optimize the module
Optimize(Composite.get());
// Generate the bytecode for the optimized module.
std::string RealBytecodeOutput = OutputFilename;
if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
GenerateBytecode(Composite.get(), RealBytecodeOutput);
// If we are not linking a library, generate either a native executable
// or a JIT shell script, depending upon what the user wants.
if (!LinkAsLibrary) {
// If the user wants to generate a native executable, compile it from the
// bytecode file.
//
// Otherwise, create a script that will run the bytecode through the JIT.
if (Native) {
// Name of the Assembly Language output file
std::string AssemblyFile = OutputFilename + ".s";
// Mark the output files for removal if we get an interrupt.
sys::RemoveFileOnSignal(sys::Path(AssemblyFile));
sys::RemoveFileOnSignal(sys::Path(OutputFilename));
// Determine the locations of the llc and gcc programs.
std::string llc = FindExecutable("llc", argv[0]).toString();
if (llc.empty())
return PrintAndReturn("Failed to find llc");
std::string gcc = FindExecutable("gcc", argv[0]).toString();
if (gcc.empty())
return PrintAndReturn("Failed to find gcc");
// Generate an assembly language file for the bytecode.
if (Verbose) std::cout << "Generating Assembly Code\n";
GenerateAssembly(AssemblyFile, RealBytecodeOutput, llc, envp);
if (Verbose) std::cout << "Generating Native Code\n";
GenerateNative(OutputFilename, AssemblyFile, Libraries, LibPaths,
gcc, envp);
// Remove the assembly language file.
removeFile (AssemblyFile);
} else if (NativeCBE) {
std::string CFile = OutputFilename + ".cbe.c";
// Mark the output files for removal if we get an interrupt.
sys::RemoveFileOnSignal(sys::Path(CFile));
sys::RemoveFileOnSignal(sys::Path(OutputFilename));
// Determine the locations of the llc and gcc programs.
std::string llc = FindExecutable("llc", argv[0]).toString();
if (llc.empty())
return PrintAndReturn("Failed to find llc");
std::string gcc = FindExecutable("gcc", argv[0]).toString();
if (gcc.empty())
return PrintAndReturn("Failed to find gcc");
// Generate an assembly language file for the bytecode.
if (Verbose) std::cout << "Generating Assembly Code\n";
GenerateCFile(CFile, RealBytecodeOutput, llc, envp);
if (Verbose) std::cout << "Generating Native Code\n";
GenerateNative(OutputFilename, CFile, Libraries, LibPaths, gcc, envp);
// Remove the assembly language file.
removeFile(CFile);
} else {
EmitShellScript(argv);
}
// Make the script executable...
sys::Path(OutputFilename).makeExecutable();
// Make the bytecode file readable and directly executable in LLEE as well
sys::Path(RealBytecodeOutput).makeExecutable();
sys::Path(RealBytecodeOutput).makeReadable();
}
return 0;
}