//===- 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/Linker.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/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 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass")); cl::opt Verify("verify", cl::desc("Verify intermediate results of all passes")); cl::opt 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 = '='; } return; } 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()); } /// 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("gccld", 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) { if (Internalize) { // 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()); } // 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()); // Propagate constants at call sites into the functions they call. addPass(Passes, createIPSCCPPass()); // 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, 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. /// envp - The environment to use when running LLC. /// /// Return non-zero value on error. /// int llvm::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. int llvm::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. /// int llvm::GenerateNative(const std::string &OutputFilename, const std::string &InputFilename, const std::vector &Libraries, const std::vector &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 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 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); }