llvm/tools/gccld/gccld.cpp
2004-02-19 20:32:39 +00:00

317 lines
11 KiB
C++

//===- gccld.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 "gccld.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Linker.h"
#include "Support/CommandLine.h"
#include "Support/FileUtilities.h"
#include "Support/Signals.h"
#include "Support/SystemUtils.h"
#include <fstream>
#include <memory>
using namespace llvm;
namespace {
cl::list<std::string>
InputFilenames(cl::Positional, cl::desc("<input bytecode files>"),
cl::OneOrMore);
cl::opt<std::string>
OutputFilename("o", cl::desc("Override output filename"), cl::init("a.out"),
cl::value_desc("filename"));
cl::opt<bool>
Verbose("v", cl::desc("Print information about actions taken"));
cl::list<std::string>
LibPaths("L", cl::desc("Specify a library search path"), cl::Prefix,
cl::value_desc("directory"));
cl::list<std::string>
Libraries("l", cl::desc("Specify libraries to link to"), cl::Prefix,
cl::value_desc("library prefix"));
cl::opt<bool>
Strip("s", cl::desc("Strip symbol info from executable"));
cl::opt<bool>
NoInternalize("disable-internalize",
cl::desc("Do not mark all symbols as internal"));
cl::alias
ExportDynamic("export-dynamic", cl::desc("Alias for -disable-internalize"),
cl::aliasopt(NoInternalize));
cl::opt<bool>
LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a"
" library, not an executable"));
cl::alias
Relink("r", cl::desc("Alias for -link-as-library"),
cl::aliasopt(LinkAsLibrary));
cl::opt<bool>
Native("native",
cl::desc("Generate a native binary instead of a shell script"));
// Compatibility options that are ignored but supported by LD
cl::opt<std::string>
CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored"));
cl::opt<std::string>
CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored"));
cl::opt<bool>
CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored"));
cl::opt<std::string>
CO6("h", cl::Hidden, cl::desc("Compatibility option: ignored"));
}
namespace llvm {
/// PrintAndReturn - Prints a message to standard error and returns a value
/// usable for an exit status.
///
/// Inputs:
/// progname - The name of the program (i.e. argv[0]).
/// Message - The message to print to standard error.
/// Extra - Extra information to print between the program name and thei
/// message. It is optional.
///
/// Return value:
/// Returns a value that can be used as the exit status (i.e. for exit()).
///
int
PrintAndReturn(const char *progname,
const std::string &Message,
const std::string &Extra)
{
std::cerr << progname << Extra << ": " << 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).
///
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).
///
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;
}
} // End llvm namespace
int main(int argc, char **argv, char **envp) {
cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n");
PrintStackTraceOnErrorSignal();
std::string ModuleID("gccld-output");
std::auto_ptr<Module> Composite(new Module(ModuleID));
// We always look first in the current directory when searching for libraries.
LibPaths.insert(LibPaths.begin(), ".");
// If the user specified an extra search path in their environment, respect
// it.
if (char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"))
LibPaths.push_back(SearchPath);
// Remove any consecutive duplicates of the same library...
Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
Libraries.end());
// Link in all of the files
if (LinkFiles(argv[0], Composite.get(), InputFilenames, Verbose))
return 1; // Error already printed
if (!LinkAsLibrary)
LinkLibraries(argv[0], Composite.get(), Libraries, LibPaths,
Verbose, Native);
// Link in all of the libraries next...
// Create the output file.
std::string RealBytecodeOutput = OutputFilename;
if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
std::ofstream Out(RealBytecodeOutput.c_str());
if (!Out.good())
return PrintAndReturn(argv[0], "error opening '" + RealBytecodeOutput +
"' for writing!");
// Ensure that the bytecode file gets removed from the disk if we get a
// SIGINT signal.
RemoveFileOnSignal(RealBytecodeOutput);
// Generate the bytecode file.
if (GenerateBytecode(Composite.get(), Strip, !NoInternalize, &Out)) {
Out.close();
return PrintAndReturn(argv[0], "error generating bytecode");
}
// Close the bytecode file.
Out.close();
// 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.
RemoveFileOnSignal(AssemblyFile);
RemoveFileOnSignal(OutputFilename);
// Determine the locations of the llc and gcc programs.
std::string llc = FindExecutable("llc", argv[0]);
std::string gcc = FindExecutable("gcc", argv[0]);
if (llc.empty())
return PrintAndReturn(argv[0], "Failed to find llc");
if (gcc.empty())
return PrintAndReturn(argv[0], "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 {
// Output the script to start the program...
std::ofstream Out2(OutputFilename.c_str());
if (!Out2.good())
return PrintAndReturn(argv[0], "error opening '" + OutputFilename +
"' for writing!");
Out2 << "#!/bin/sh\nlli \\\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) {
std::string FullLibraryPath = FindLib(*i, LibPaths, true);
if (!FullLibraryPath.empty() && IsSharedObject(FullLibraryPath))
Out2 << " -load=" << FullLibraryPath << " \\\n";
}
Out2 << " $0.bc $*\n";
Out2.close();
}
// Make the script executable...
MakeFileExecutable(OutputFilename);
// Make the bytecode file readable and directly executable in LLEE as well
MakeFileExecutable(RealBytecodeOutput);
MakeFileReadable(RealBytecodeOutput);
}
return 0;
}