llc.cpp revision 540f7d60181d64ce25fa277de51ac7e3ded8acae 
1//===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
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.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is the llc code generator driver. It provides a convenient
11// command-line interface for generating native assembly-language code
12// or C code, given LLVM bytecode.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/Bytecode/Reader.h"
17#include "llvm/Target/TargetMachine.h"
18#include "llvm/Target/TargetMachineRegistry.h"
19#include "llvm/Transforms/Scalar.h"
20#include "llvm/Module.h"
21#include "llvm/PassManager.h"
22#include "llvm/Pass.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Support/PluginLoader.h"
25#include "llvm/Support/PassNameParser.h"
26#include "llvm/Analysis/Verifier.h"
27#include "llvm/System/Signals.h"
28#include "llvm/Config/config.h"
29#include <fstream>
30#include <iostream>
31#include <memory>
32
33using namespace llvm;
34
35// General options for llc.  Other pass-specific options are specified
36// within the corresponding llc passes, and target-specific options
37// and back-end code generation options are specified with the target machine.
38//
39static cl::opt<std::string>
40InputFilename(cl::Positional, cl::desc("<input bytecode>"), cl::init("-"));
41
42static cl::opt<std::string>
43OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
44
45static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
46
47static cl::opt<const TargetMachineRegistry::Entry*, false, TargetNameParser>
48MArch("march", cl::desc("Architecture to generate code for:"));
49
50cl::opt<TargetMachine::CodeGenFileType>
51FileType("filetype", cl::init(TargetMachine::AssemblyFile),
52  cl::desc("Choose a file type (not all types are supported by all targets):"),
53  cl::values(
54       clEnumValN(TargetMachine::AssemblyFile,    "asm",
55                  "  Emit an assembly ('.s') file"),
56       clEnumValN(TargetMachine::ObjectFile,    "obj",
57                  "  Emit a native object ('.o') file"),
58       clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
59                  "  Emit a native dynamic library ('.so') file"),
60       clEnumValEnd));
61
62// The LLCPassList is populated with passes that were registered using
63//  PassInfo::LLC by the FilteredPassNameParser:
64cl::list<const PassInfo*, bool, FilteredPassNameParser<PassInfo::LLC> >
65LLCPassList(cl::desc("Passes Available"));
66
67cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
68		       cl::desc("Do not verify input module"));
69
70
71// GetFileNameRoot - Helper function to get the basename of a filename.
72static inline std::string
73GetFileNameRoot(const std::string &InputFilename) {
74  std::string IFN = InputFilename;
75  std::string outputFilename;
76  int Len = IFN.length();
77  if ((Len > 2) &&
78      IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
79    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
80  } else {
81    outputFilename = IFN;
82  }
83  return outputFilename;
84}
85
86
87// main - Entry point for the llc compiler.
88//
89int main(int argc, char **argv) {
90  try {
91    cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
92    sys::PrintStackTraceOnErrorSignal();
93
94    // Load the module to be compiled...
95    std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
96    if (M.get() == 0) {
97      std::cerr << argv[0] << ": bytecode didn't read correctly.\n";
98      return 1;
99    }
100    Module &mod = *M.get();
101
102    // Allocate target machine.  First, check whether the user has
103    // explicitly specified an architecture to compile for.
104    TargetMachine* (*TargetMachineAllocator)(const Module&,
105                                             IntrinsicLowering *) = 0;
106    if (MArch == 0) {
107      std::string Err;
108      MArch = TargetMachineRegistry::getClosestStaticTargetForModule(mod, Err);
109      if (MArch == 0) {
110        std::cerr << argv[0] << ": error auto-selecting target for module '"
111                  << Err << "'.  Please use the -march option to explicitly "
112                  << "pick a target.\n";
113        return 1;
114      }
115    }
116
117    std::auto_ptr<TargetMachine> target(MArch->CtorFn(mod, 0));
118    assert(target.get() && "Could not allocate target machine!");
119    TargetMachine &Target = *target.get();
120    const TargetData &TD = Target.getTargetData();
121
122    // Build up all of the passes that we want to do to the module...
123    PassManager Passes;
124    Passes.add(new TargetData(TD));
125
126    // Create a new pass for each one specified on the command line
127    for (unsigned i = 0; i < LLCPassList.size(); ++i) {
128      const PassInfo *aPass = LLCPassList[i];
129
130      if (aPass->getNormalCtor()) {
131        Pass *P = aPass->getNormalCtor()();
132        Passes.add(P);
133      } else {
134        std::cerr << argv[0] << ": cannot create pass: "
135                  << aPass->getPassName() << "\n";
136      }
137    }
138
139#ifndef NDEBUG
140    if(!NoVerify)
141      Passes.add(createVerifierPass());
142#endif
143
144    // Figure out where we are going to send the output...
145    std::ostream *Out = 0;
146    if (OutputFilename != "") {
147      if (OutputFilename != "-") {
148        // Specified an output filename?
149        if (!Force && std::ifstream(OutputFilename.c_str())) {
150          // If force is not specified, make sure not to overwrite a file!
151          std::cerr << argv[0] << ": error opening '" << OutputFilename
152                    << "': file exists!\n"
153                    << "Use -f command line argument to force output\n";
154          return 1;
155        }
156        Out = new std::ofstream(OutputFilename.c_str());
157
158        // Make sure that the Out file gets unlinked from the disk if we get a
159        // SIGINT
160        sys::RemoveFileOnSignal(sys::Path(OutputFilename));
161      } else {
162        Out = &std::cout;
163      }
164    } else {
165      if (InputFilename == "-") {
166        OutputFilename = "-";
167        Out = &std::cout;
168      } else {
169        OutputFilename = GetFileNameRoot(InputFilename);
170
171        switch (FileType) {
172        case TargetMachine::AssemblyFile:
173          if (MArch->Name[0] != 'c' || MArch->Name[1] != 0)  // not CBE
174            OutputFilename += ".s";
175          else
176            OutputFilename += ".cbe.c";
177          break;
178        case TargetMachine::ObjectFile:
179          OutputFilename += ".o";
180          break;
181        case TargetMachine::DynamicLibrary:
182          OutputFilename += LTDL_SHLIB_EXT;
183          break;
184        }
185
186        if (!Force && std::ifstream(OutputFilename.c_str())) {
187          // If force is not specified, make sure not to overwrite a file!
188          std::cerr << argv[0] << ": error opening '" << OutputFilename
189                    << "': file exists!\n"
190                    << "Use -f command line argument to force output\n";
191          return 1;
192        }
193
194        Out = new std::ofstream(OutputFilename.c_str());
195        if (!Out->good()) {
196          std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
197          delete Out;
198          return 1;
199        }
200
201        // Make sure that the Out file gets unlinked from the disk if we get a
202        // SIGINT
203        sys::RemoveFileOnSignal(sys::Path(OutputFilename));
204      }
205    }
206
207    // Ask the target to add backend passes as necessary.
208    if (Target.addPassesToEmitFile(Passes, *Out, FileType)) {
209      std::cerr << argv[0] << ": target '" << Target.getName()
210                << "' does not support generation of this file type!\n";
211      if (Out != &std::cout) delete Out;
212      // And the Out file is empty and useless, so remove it now.
213      std::remove(OutputFilename.c_str());
214      return 1;
215    } else {
216      // Run our queue of passes all at once now, efficiently.
217      Passes.run(*M.get());
218    }
219
220    // Delete the ostream if it's not a stdout stream
221    if (Out != &std::cout) delete Out;
222
223    return 0;
224  } catch (const std::string& msg) {
225    std::cerr << argv[0] << ": " << msg << "\n";
226  } catch (...) {
227    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
228  }
229  return 1;
230}
231