1 //===- GenerateCode.cpp - Functions for generating executable files ------===//
3 // This file contains functions for generating executable files once linking
4 // has finished. This includes generating a shell script to run the JIT or
5 // a native executable derived from the bytecode.
7 //===----------------------------------------------------------------------===//
10 #include "llvm/Module.h"
11 #include "llvm/PassManager.h"
12 #include "llvm/Bytecode/WriteBytecodePass.h"
13 #include "llvm/Target/TargetData.h"
14 #include "llvm/Transforms/IPO.h"
15 #include "llvm/Transforms/Scalar.h"
16 #include "llvm/Transforms/Utils/Linker.h"
17 #include "Support/SystemUtils.h"
20 // Function: GenerateBytecode ()
23 // This function generates a bytecode file from the specified module.
26 // M - The module for which bytecode should be generated.
27 // Strip - Flags whether symbols should be stripped from the output.
28 // Internalize - Flags whether all symbols should be marked internal.
29 // Out - Pointer to file stream to which to write the output.
39 GenerateBytecode (Module *M, bool Strip, bool Internalize, std::ostream *Out) {
40 // In addition to just linking the input from GCC, we also want to spiff it up
41 // a little bit. Do this now.
44 // Add an appropriate TargetData instance for this module...
45 Passes.add(new TargetData("gccld", M));
47 // Linking modules together can lead to duplicated global constants, only keep
48 // one copy of each constant...
49 Passes.add(createConstantMergePass());
51 // If the -s command line option was specified, strip the symbols out of the
52 // resulting program to make it smaller. -s is a GCC option that we are
55 Passes.add(createSymbolStrippingPass());
57 // Often if the programmer does not specify proper prototypes for the
58 // functions they are calling, they end up calling a vararg version of the
59 // function that does not get a body filled in (the real function has typed
60 // arguments). This pass merges the two functions.
61 Passes.add(createFunctionResolvingPass());
64 // Now that composite has been compiled, scan through the module, looking
65 // for a main function. If main is defined, mark all other functions
67 Passes.add(createInternalizePass());
70 // Remove unused arguments from functions...
71 Passes.add(createDeadArgEliminationPass());
73 // The FuncResolve pass may leave cruft around if functions were prototyped
74 // differently than they were defined. Remove this cruft.
75 Passes.add(createInstructionCombiningPass());
77 // Delete basic blocks, which optimization passes may have killed...
78 Passes.add(createCFGSimplificationPass());
80 // Now that we have optimized the program, discard unreachable functions...
81 Passes.add(createGlobalDCEPass());
83 // Add the pass that writes bytecode to the output file...
84 Passes.add(new WriteBytecodePass(Out));
86 // Run our queue of passes all at once now, efficiently.
93 // Function: GenerateAssembly ()
96 // This function generates a native assembly language source file from the
97 // specified bytecode file.
100 // InputFilename - The name of the output bytecode file.
101 // OutputFilename - The name of the file to generate.
102 // llc - The pathname to use for LLC.
103 // envp - The environment to use when running LLC.
113 GenerateAssembly(const std::string &OutputFilename,
114 const std::string &InputFilename,
115 const std::string &llc,
118 // Run LLC to convert the bytecode file into assembly code.
121 cmd[0] = llc.c_str();
124 cmd[3] = OutputFilename.c_str();
125 cmd[4] = InputFilename.c_str();
128 return ExecWait(cmd, envp);
132 // Function: GenerateNative ()
135 // This function generates a native assembly language source file from the
136 // specified assembly source file.
139 // InputFilename - The name of the output bytecode file.
140 // OutputFilename - The name of the file to generate.
141 // Libraries - The list of libraries with which to link.
142 // LibPaths - The list of directories in which to find libraries.
143 // gcc - The pathname to use for GGC.
144 // envp - A copy of the process's current environment.
154 GenerateNative(const std::string &OutputFilename,
155 const std::string &InputFilename,
156 const std::vector<std::string> &Libraries,
157 const std::vector<std::string> &LibPaths,
158 const std::string &gcc,
159 char ** const envp) {
160 // Remove these environment variables from the environment of the
161 // programs that we will execute. It appears that GCC sets these
162 // environment variables so that the programs it uses can configure
163 // themselves identically.
165 // However, when we invoke GCC below, we want it to use its normal
166 // configuration. Hence, we must sanitize its environment.
167 char ** clean_env = CopyEnv(envp);
168 if (clean_env == NULL)
170 RemoveEnv("LIBRARY_PATH", clean_env);
171 RemoveEnv("COLLECT_GCC_OPTIONS", clean_env);
172 RemoveEnv("GCC_EXEC_PREFIX", clean_env);
173 RemoveEnv("COMPILER_PATH", clean_env);
174 RemoveEnv("COLLECT_GCC", clean_env);
176 std::vector<const char *> cmd;
178 // Run GCC to assemble and link the program into native code.
181 // We can't just assemble and link the file with the system assembler
182 // and linker because we don't know where to put the _start symbol.
183 // GCC mysteriously knows how to do it.
184 cmd.push_back(gcc.c_str());
186 cmd.push_back(OutputFilename.c_str());
187 cmd.push_back(InputFilename.c_str());
189 // Adding the library paths creates a problem for native generation. If we
190 // include the search paths from llvmgcc, then we'll be telling normal gcc
191 // to look inside of llvmgcc's library directories for libraries. This is
192 // bad because those libraries hold only bytecode files (not native object
193 // files). In the end, we attempt to link the bytecode libgcc into a native
196 // Add in the library path options.
197 for (unsigned index=0; index < LibPaths.size(); index++) {
199 cmd.push_back(LibPaths[index].c_str());
203 // Add in the libraries to link.
204 std::vector<std::string> Libs(Libraries);
205 for (unsigned index = 0; index < Libs.size(); index++) {
206 Libs[index] = "-l" + Libs[index];
207 cmd.push_back(Libs[index].c_str());
211 // Run the compiler to assembly and link together the program.
212 return ExecWait(&(cmd[0]), clean_env);