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llvm-project/llvm/tools/gccld/GenerateCode.cpp

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//===- GenerateCode.cpp - Functions for generating executable files ------===//
//
// 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 file contains functions for generating executable files once linking
// has finished. This includes generating a shell script to run the JIT or
// a native executable derived from the bytecode.
//
//===----------------------------------------------------------------------===//
#include "gccld.h"
#include "llvm/System/Program.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bytecode/Archive.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
namespace {
cl::opt<bool>
DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
cl::opt<bool>
Verify("verify", cl::desc("Verify intermediate results of all passes"));
cl::opt<bool>
DisableOptimizations("disable-opt",
cl::desc("Do not run any optimization passes"));
}
/// 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 = '=';
}
}
static void dumpArgs(const char **args) {
std::cerr << *args++;
while (*args)
std::cerr << ' ' << *args++;
std::cerr << '\n' << std::flush;
}
static inline void addPass(PassManager &PM, Pass *P) {
// Add the pass to the pass manager...
PM.add(P);
// If we are verifying all of the intermediate steps, add the verifier...
if (Verify) PM.add(createVerifierPass());
}
static bool isBytecodeLibrary(const sys::Path &FullPath) {
// Check for a bytecode file
if (FullPath.isBytecodeFile()) return true;
// Check for a dynamic library file
if (FullPath.isDynamicLibrary()) return false;
// Check for a true bytecode archive file
if (FullPath.isArchive() ) {
std::string ErrorMessage;
Archive* ar = Archive::OpenAndLoadSymbols( FullPath, &ErrorMessage );
return ar->isBytecodeArchive();
}
return false;
}
static bool isBytecodeLPath(const std::string &LibPath) {
sys::Path LPath(LibPath);
// Make sure it exists and is a directory
sys::FileStatus Status;
if (LPath.getFileStatus(Status) || !Status.isDir)
return false;
// Grab the contents of the -L path
std::set<sys::Path> Files;
if (LPath.getDirectoryContents(Files, 0))
return false;
// Iterate over the contents one by one to determine
// if this -L path has any bytecode shared libraries
// or archives
std::set<sys::Path>::iterator File = Files.begin();
std::string dllsuffix = sys::Path::GetDLLSuffix();
for (; File != Files.end(); ++File) {
// Not a file?
if (File->getFileStatus(Status) || Status.isDir)
continue;
std::string path = File->toString();
// Check for an ending '.dll', '.so' or '.a' suffix as all
// other files are not of interest to us here
if (path.find(dllsuffix, path.size()-dllsuffix.size()) == std::string::npos
&& path.find(".a", path.size()-2) == std::string::npos)
continue;
// Finally, check to see if the file is a true bytecode file
if (isBytecodeLibrary(*File))
return true;
}
return false;
}
/// GenerateBytecode - generates a bytecode file from the specified module.
///
/// Inputs:
/// M - The module for which bytecode should be generated.
/// StripLevel - 2 if we should strip all symbols, 1 if we should strip
/// debug info.
/// Internalize - Flags whether all symbols should be marked internal.
/// Out - Pointer to file stream to which to write the output.
///
/// Returns non-zero value on error.
///
int llvm::GenerateBytecode(Module *M, int StripLevel, bool Internalize,
std::ostream *Out) {
// In addition to just linking the input from GCC, we also want to spiff it up
// a little bit. Do this now.
PassManager Passes;
if (Verify) Passes.add(createVerifierPass());
// Add an appropriate TargetData instance for this module...
addPass(Passes, new TargetData(M));
// Often if the programmer does not specify proper prototypes for the
// functions they are calling, they end up calling a vararg version of the
// function that does not get a body filled in (the real function has typed
// arguments). This pass merges the two functions.
addPass(Passes, createFunctionResolvingPass());
if (!DisableOptimizations) {
// Now that composite has been compiled, scan through the module, looking
// for a main function. If main is defined, mark all other functions
// internal.
addPass(Passes, createInternalizePass(Internalize));
// Propagate constants at call sites into the functions they call. This
// opens opportunities for globalopt (and inlining) by substituting function
// pointers passed as arguments to direct uses of functions.
addPass(Passes, createIPSCCPPass());
// Now that we internalized some globals, see if we can hack on them!
addPass(Passes, createGlobalOptimizerPass());
// Linking modules together can lead to duplicated global constants, only
// keep one copy of each constant...
addPass(Passes, createConstantMergePass());
// Remove unused arguments from functions...
addPass(Passes, createDeadArgEliminationPass());
if (!DisableInline)
addPass(Passes, createFunctionInliningPass()); // Inline small functions
addPass(Passes, createPruneEHPass()); // Remove dead EH info
addPass(Passes, createGlobalOptimizerPass()); // Optimize globals again.
addPass(Passes, createGlobalDCEPass()); // Remove dead functions
// If we didn't decide to inline a function, check to see if we can
// transform it to pass arguments by value instead of by reference.
addPass(Passes, createArgumentPromotionPass());
// The IPO passes may leave cruft around. Clean up after them.
addPass(Passes, createInstructionCombiningPass());
addPass(Passes, createPredicateSimplifierPass());
addPass(Passes, createScalarReplAggregatesPass()); // Break up allocas
// Run a few AA driven optimizations here and now, to cleanup the code.
addPass(Passes, createGlobalsModRefPass()); // IP alias analysis
addPass(Passes, createLICMPass()); // Hoist loop invariants
addPass(Passes, createLoadValueNumberingPass()); // GVN for load instrs
addPass(Passes, createGCSEPass()); // Remove common subexprs
addPass(Passes, createDeadStoreEliminationPass()); // Nuke dead stores
// Cleanup and simplify the code after the scalar optimizations.
addPass(Passes, createInstructionCombiningPass());
// Delete basic blocks, which optimization passes may have killed...
addPass(Passes, createCFGSimplificationPass());
// Now that we have optimized the program, discard unreachable functions...
addPass(Passes, createGlobalDCEPass());
}
// If the -s or -S command line options were specified, strip the symbols out
// of the resulting program to make it smaller. -s and -S are GLD options
// that we are supporting.
if (StripLevel)
addPass(Passes, createStripSymbolsPass(StripLevel == 1));
// Make sure everything is still good.
Passes.add(createVerifierPass());
// Add the pass that writes bytecode to the output file...
addPass(Passes, new WriteBytecodePass(Out));
// Run our queue of passes all at once now, efficiently.
Passes.run(*M);
return 0;
}
/// 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.
///
/// Return non-zero value on error.
///
int llvm::GenerateAssembly(const std::string &OutputFilename,
const std::string &InputFilename,
const sys::Path &llc,
std::string& ErrMsg,
bool Verbose) {
// Run LLC to convert the bytecode file into assembly code.
std::vector<const char*> args;
args.push_back(llc.c_str());
args.push_back("-f");
args.push_back("-o");
args.push_back(OutputFilename.c_str());
args.push_back(InputFilename.c_str());
args.push_back(0);
if (Verbose) dumpArgs(&args[0]);
return sys::Program::ExecuteAndWait(llc, &args[0],0,0,0,&ErrMsg);
}
/// GenerateCFile - generates a C source file from the specified bytecode file.
int llvm::GenerateCFile(const std::string &OutputFile,
const std::string &InputFile,
const sys::Path &llc,
std::string& ErrMsg,
bool Verbose) {
// Run LLC to convert the bytecode file into C.
std::vector<const char*> args;
args.push_back(llc.c_str());
args.push_back("-march=c");
args.push_back("-f");
args.push_back("-o");
args.push_back(OutputFile.c_str());
args.push_back(InputFile.c_str());
args.push_back(0);
if (Verbose) dumpArgs(&args[0]);
return sys::Program::ExecuteAndWait(llc, &args[0],0,0,0,&ErrMsg);
}
/// GenerateNative - generates a native executable 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.
/// gcc - The pathname to use for GGC.
/// envp - A copy of the process's current environment.
///
/// Outputs:
/// None.
///
/// Returns non-zero value on error.
///
int llvm::GenerateNative(const std::string &OutputFilename,
const std::string &InputFilename,
const std::vector<std::string> &LibPaths,
const std::vector<std::string> &Libraries,
const sys::Path &gcc, char ** const envp,
bool Shared,
bool ExportAllAsDynamic,
const std::vector<std::string> &RPaths,
const std::string &SOName,
std::string& ErrMsg,
bool Verbose) {
// 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);
// 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.
std::vector<const char*> args;
args.push_back(gcc.c_str());
args.push_back("-fno-strict-aliasing");
args.push_back("-O3");
args.push_back("-o");
args.push_back(OutputFilename.c_str());
args.push_back(InputFilename.c_str());
// StringsToDelete - We don't want to call c_str() on temporary strings.
// If we need a temporary string, copy it here so that the memory is not
// reclaimed until after the exec call. All of these strings are allocated
// with strdup.
std::vector<char*> StringsToDelete;
if (Shared) args.push_back("-shared");
if (ExportAllAsDynamic) args.push_back("-export-dynamic");
if (!RPaths.empty()) {
for (std::vector<std::string>::const_iterator I = RPaths.begin(),
E = RPaths.end(); I != E; I++) {
std::string rp = "-Wl,-rpath," + *I;
StringsToDelete.push_back(strdup(rp.c_str()));
args.push_back(StringsToDelete.back());
}
}
if (!SOName.empty()) {
std::string so = "-Wl,-soname," + SOName;
StringsToDelete.push_back(strdup(so.c_str()));
args.push_back(StringsToDelete.back());
}
// Add in the libpaths to find the libraries.
//
// Note:
// When gccld is called from the llvm-gxx frontends, the -L paths for
// the LLVM cfrontend install paths are appended. We don't want the
// native linker to use these -L paths as they contain bytecode files.
// Further, we don't want any -L paths that contain bytecode shared
// libraries or true bytecode archive files. We omit them in all such
// cases.
for (unsigned index = 0; index < LibPaths.size(); index++)
if (!isBytecodeLPath(LibPaths[index])) {
std::string Tmp = "-L"+LibPaths[index];
StringsToDelete.push_back(strdup(Tmp.c_str()));
args.push_back(StringsToDelete.back());
}
// Add in the libraries to link.
for (unsigned index = 0; index < Libraries.size(); index++)
// HACK: If this is libg, discard it. This gets added by the compiler
// driver when doing: 'llvm-gcc main.c -Wl,-native -o a.out -g'. Note that
// this should really be fixed by changing the llvm-gcc compiler driver.
if (Libraries[index] != "crtend" && Libraries[index] != "g") {
std::string Tmp = "-l"+Libraries[index];
StringsToDelete.push_back(strdup(Tmp.c_str()));
args.push_back(StringsToDelete.back());
}
args.push_back(0); // Null terminate.
// Run the compiler to assembly and link together the program.
if (Verbose) dumpArgs(&args[0]);
int Res = sys::Program::ExecuteAndWait(
gcc, &args[0],(const char**)clean_env,0,0,&ErrMsg);
delete [] clean_env;
while (!StringsToDelete.empty()) {
free(StringsToDelete.back());
StringsToDelete.pop_back();
}
return Res;
}
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