1 //===- gccld.cpp - LLVM 'ld' compatible linker ----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This utility is intended to be compatible with GCC, and follows standard
11 // system 'ld' conventions. As such, the default output file is ./a.out.
12 // Additionally, this program outputs a shell script that is used to invoke LLI
13 // to execute the program. In this manner, the generated executable (a.out for
14 // example), is directly executable, whereas the bytecode file actually lives in
15 // the a.out.bc file generated by this program. Also, Force is on by default.
17 // Note that if someone (or a script) deletes the executable program generated,
18 // the .bc file will be left around. Considering that this is a temporary hack,
19 // I'm not too worried about this.
21 //===----------------------------------------------------------------------===//
24 #include "llvm/Module.h"
25 #include "llvm/PassManager.h"
26 #include "llvm/Bytecode/Reader.h"
27 #include "llvm/Bytecode/WriteBytecodePass.h"
28 #include "llvm/Target/TargetData.h"
29 #include "llvm/Transforms/IPO.h"
30 #include "llvm/Transforms/Scalar.h"
31 #include "llvm/Transforms/Utils/Linker.h"
32 #include "Support/CommandLine.h"
33 #include "Support/FileUtilities.h"
34 #include "Support/Signals.h"
35 #include "Support/SystemUtils.h"
41 InputFilenames(cl::Positional, cl::desc("<input bytecode files>"),
45 OutputFilename("o", cl::desc("Override output filename"), cl::init("a.out"),
46 cl::value_desc("filename"));
49 Verbose("v", cl::desc("Print information about actions taken"));
52 LibPaths("L", cl::desc("Specify a library search path"), cl::Prefix,
53 cl::value_desc("directory"));
56 Libraries("l", cl::desc("Specify libraries to link to"), cl::Prefix,
57 cl::value_desc("library prefix"));
60 Strip("s", cl::desc("Strip symbol info from executable"));
63 NoInternalize("disable-internalize",
64 cl::desc("Do not mark all symbols as internal"));
66 ExportDynamic("export-dynamic", cl::desc("Alias for -disable-internalize"),
67 cl::aliasopt(NoInternalize));
70 LinkAsLibrary("link-as-library", cl::desc("Link the .bc files together as a"
71 " library, not an executable"));
75 cl::desc("Generate a native binary instead of a shell script"));
77 // Compatibility options that are ignored but supported by LD
79 CO3("soname", cl::Hidden, cl::desc("Compatibility option: ignored"));
81 CO4("version-script", cl::Hidden, cl::desc("Compatibility option: ignored"));
83 CO5("eh-frame-hdr", cl::Hidden, cl::desc("Compatibility option: ignored"));
85 CO6("r", cl::Hidden, cl::desc("Compatibility option: ignored"));
89 // Function: PrintAndReturn ()
92 // Prints a message (usually error message) to standard error (stderr) and
93 // returns a value usable for an exit status.
96 // progname - The name of the program (i.e. argv[0]).
97 // Message - The message to print to standard error.
98 // Extra - Extra information to print between the program name and thei
99 // message. It is optional.
105 // Returns a value that can be used as the exit status (i.e. for exit()).
108 PrintAndReturn (const char *progname,
109 const std::string &Message,
110 const std::string &Extra)
112 std::cerr << progname << Extra << ": " << Message << "\n";
118 // Function: CopyEnv()
121 // This function takes an array of environment variables and makes a
122 // copy of it. This copy can then be manipulated any way the caller likes
123 // without affecting the process's real environment.
126 // envp - An array of C strings containing an environment.
132 // NULL - An error occurred.
134 // Otherwise, a pointer to a new array of C strings is returned. Every string
135 // in the array is a duplicate of the one in the original array (i.e. we do
136 // not copy the char *'s from one array to another).
138 char ** CopyEnv(char ** const envp) {
139 // Count the number of entries in the old list;
140 unsigned entries; // The number of entries in the old environment list
141 for (entries = 0; envp[entries] != NULL; entries++)
146 // Add one more entry for the NULL pointer that ends the list.
149 // If there are no entries at all, just return NULL.
153 // Allocate a new environment list.
155 if ((newenv = new (char *) [entries]) == NULL)
158 // Make a copy of the list. Don't forget the NULL that ends the list.
160 while (envp[entries] != NULL) {
161 newenv[entries] = new char[strlen (envp[entries]) + 1];
162 strcpy (newenv[entries], envp[entries]);
165 newenv[entries] = NULL;
172 // Function: RemoveEnv()
175 // Remove the specified environment variable from the environment array.
178 // name - The name of the variable to remove. It cannot be NULL.
179 // envp - The array of environment variables. It cannot be NULL.
182 // envp - The pointer to the specified variable name is removed.
188 // This is mainly done because functions to remove items from the environment
189 // are not available across all platforms. In particular, Solaris does not
190 // seem to have an unsetenv() function or a setenv() function (or they are
191 // undocumented if they do exist).
193 void RemoveEnv(const char * name, char ** const envp) {
194 for (unsigned index=0; envp[index] != NULL; index++) {
195 // Find the first equals sign in the array and make it an EOS character.
196 char *p = strchr (envp[index], '=');
202 // Compare the two strings. If they are equal, zap this string.
203 // Otherwise, restore it.
204 if (!strcmp(name, envp[index]))
214 int main(int argc, char **argv, char **envp) {
215 cl::ParseCommandLineOptions(argc, argv, " llvm linker for GCC\n");
217 std::string ErrorMessage;
218 std::auto_ptr<Module> Composite(LoadObject(InputFilenames[0], ErrorMessage));
219 if (Composite.get() == 0)
220 return PrintAndReturn(argv[0], ErrorMessage);
222 // We always look first in the current directory when searching for libraries.
223 LibPaths.insert(LibPaths.begin(), ".");
225 // If the user specified an extra search path in their environment, respect
227 if (char *SearchPath = getenv("LLVM_LIB_SEARCH_PATH"))
228 LibPaths.push_back(SearchPath);
230 // Remove any consecutive duplicates of the same library...
231 Libraries.erase(std::unique(Libraries.begin(), Libraries.end()),
234 // Link in all of the files
235 if (LinkFiles(argv[0], Composite.get(), InputFilenames, Verbose))
236 return 1; // Error already printed
237 LinkLibraries(argv[0], Composite.get(), Libraries, LibPaths, Verbose, Native);
239 // Link in all of the libraries next...
241 // Create the output file.
242 std::string RealBytecodeOutput = OutputFilename;
243 if (!LinkAsLibrary) RealBytecodeOutput += ".bc";
244 std::ofstream Out(RealBytecodeOutput.c_str());
246 return PrintAndReturn(argv[0], "error opening '" + RealBytecodeOutput +
249 // Ensure that the bytecode file gets removed from the disk if we get a
251 RemoveFileOnSignal(RealBytecodeOutput);
253 // Generate the bytecode file.
254 if (GenerateBytecode(Composite.get(), Strip, !NoInternalize, &Out)) {
256 return PrintAndReturn(argv[0], "error generating bytcode");
259 // Close the bytecode file.
262 // If we are not linking a library, generate either a native executable
263 // or a JIT shell script, depending upon what the user wants.
264 if (!LinkAsLibrary) {
265 // If the user wants to generate a native executable, compile it from the
268 // Otherwise, create a script that will run the bytecode through the JIT.
270 // Name of the Assembly Language output file
271 std::string AssemblyFile = OutputFilename + ".s";
273 // Mark the output files for removal if we get an interrupt.
274 RemoveFileOnSignal(AssemblyFile);
275 RemoveFileOnSignal(OutputFilename);
277 // Determine the locations of the llc and gcc programs.
278 std::string llc = FindExecutable("llc", argv[0]);
279 std::string gcc = FindExecutable("gcc", argv[0]);
281 return PrintAndReturn(argv[0], "Failed to find llc");
284 return PrintAndReturn(argv[0], "Failed to find gcc");
286 // Generate an assembly language file for the bytecode.
287 if (Verbose) std::cout << "Generating Assembly Code\n";
288 GenerateAssembly(AssemblyFile, RealBytecodeOutput, llc, envp);
289 if (Verbose) std::cout << "Generating Native Code\n";
290 GenerateNative(OutputFilename, AssemblyFile, Libraries, LibPaths,
293 // Remove the assembly language file.
294 removeFile (AssemblyFile);
296 // Output the script to start the program...
297 std::ofstream Out2(OutputFilename.c_str());
299 return PrintAndReturn(argv[0], "error opening '" + OutputFilename +
301 Out2 << "#!/bin/sh\nlli $0.bc $*\n";
305 // Make the script executable...
306 MakeFileExecutable(OutputFilename);
308 // Make the bytecode file readable and directly executable in LLEE as well
309 MakeFileExecutable(RealBytecodeOutput);
310 MakeFileReadable(RealBytecodeOutput);