Initial implementation of llvm-ld: stolen from gccld.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-ld/GenerateCode.cpp b/tools/llvm-ld/GenerateCode.cpp
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+++ b/tools/llvm-ld/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 "llvm-ld.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/Linker.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 = '=';
+ }
+
+ 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.
+/// Strip - Flags whether symbols should be stripped from the output.
+/// 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, bool Strip, 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 mark any globals as
+ // being constant!
+ addPass(Passes, createGlobalConstifierPass());
+
+ // Linking modules together can lead to duplicated global constants, only
+ // keep one copy of each constant...
+ addPass(Passes, createConstantMergePass());
+
+ // If the -s command line option was specified, strip the symbols out of the
+ // resulting program to make it smaller. -s is a GCC option that we are
+ // supporting.
+ if (Strip)
+ addPass(Passes, createSymbolStrippingPass());
+
+ // Propagate constants at call sites into the functions they call.
+ addPass(Passes, createIPConstantPropagationPass());
+
+ // 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, 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());
+ }
+
+ // 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<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);
+}
+