llc.cpp revision ea8aed7ef38077e17253b15f5e7b52b1b5d1db92 
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/SubtargetFeature.h"
18#include "llvm/Target/TargetMachine.h"
19#include "llvm/Target/TargetMachineRegistry.h"
20#include "llvm/Transforms/Scalar.h"
21#include "llvm/Module.h"
22#include "llvm/PassManager.h"
23#include "llvm/Pass.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/PluginLoader.h"
26#include "llvm/Support/PassNameParser.h"
27#include "llvm/Support/FileUtilities.h"
28#include "llvm/Analysis/Verifier.h"
29#include "llvm/System/Signals.h"
30#include "llvm/Config/config.h"
31#include <fstream>
32#include <iostream>
33#include <memory>
34#include <cstdio>
35
36using namespace llvm;
37
38// General options for llc.  Other pass-specific options are specified
39// within the corresponding llc passes, and target-specific options
40// and back-end code generation options are specified with the target machine.
41//
42static cl::opt<std::string>
43InputFilename(cl::Positional, cl::desc("<input bytecode>"), cl::init("-"));
44
45static cl::opt<std::string>
46OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
47
48static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
49
50static cl::opt<bool> Fast("fast",
51      cl::desc("Generate code quickly, potentially sacrificing code quality"));
52
53static cl::opt<std::string>
54TargetTriple("mtriple", cl::desc("Override target triple for module"));
55
56static cl::opt<const TargetMachineRegistry::Entry*, false, TargetNameParser>
57MArch("march", cl::desc("Architecture to generate code for:"));
58
59static cl::opt<std::string>
60MCPU("mcpu",
61  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
62  cl::value_desc("cpu-name"),
63  cl::init(""));
64
65static cl::list<std::string>
66MAttrs("mattr",
67  cl::CommaSeparated,
68  cl::desc("Target specific attributes (-mattr=help for details)"),
69  cl::value_desc("a1,+a2,-a3,..."));
70
71cl::opt<TargetMachine::CodeGenFileType>
72FileType("filetype", cl::init(TargetMachine::AssemblyFile),
73  cl::desc("Choose a file type (not all types are supported by all targets):"),
74  cl::values(
75       clEnumValN(TargetMachine::AssemblyFile,    "asm",
76                  "  Emit an assembly ('.s') file"),
77       clEnumValN(TargetMachine::ObjectFile,    "obj",
78                  "  Emit a native object ('.o') file [experimental]"),
79       clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
80                  "  Emit a native dynamic library ('.so') file"),
81       clEnumValEnd));
82
83// The LLCPassList is populated with passes that were registered using
84//  PassInfo::LLC by the FilteredPassNameParser:
85cl::list<const PassInfo*, bool, FilteredPassNameParser<PassInfo::LLC> >
86LLCPassList(cl::desc("Passes Available"));
87
88cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
89                       cl::desc("Do not verify input module"));
90
91
92// GetFileNameRoot - Helper function to get the basename of a filename.
93static inline std::string
94GetFileNameRoot(const std::string &InputFilename) {
95  std::string IFN = InputFilename;
96  std::string outputFilename;
97  int Len = IFN.length();
98  if ((Len > 2) &&
99      IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
100    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
101  } else {
102    outputFilename = IFN;
103  }
104  return outputFilename;
105}
106
107
108// main - Entry point for the llc compiler.
109//
110int main(int argc, char **argv) {
111  try {
112    cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
113    sys::PrintStackTraceOnErrorSignal();
114
115    // Load the module to be compiled...
116    std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
117    if (M.get() == 0) {
118      std::cerr << argv[0] << ": bytecode didn't read correctly.\n";
119      return 1;
120    }
121    Module &mod = *M.get();
122
123    // If we are supposed to override the target triple, do so now.
124    if (!TargetTriple.empty())
125      mod.setTargetTriple(TargetTriple);
126
127    // Allocate target machine.  First, check whether the user has
128    // explicitly specified an architecture to compile for.
129    TargetMachine* (*TargetMachineAllocator)(const Module&,
130                                             IntrinsicLowering *) = 0;
131    if (MArch == 0) {
132      std::string Err;
133      MArch = TargetMachineRegistry::getClosestStaticTargetForModule(mod, Err);
134      if (MArch == 0) {
135        std::cerr << argv[0] << ": error auto-selecting target for module '"
136                  << Err << "'.  Please use the -march option to explicitly "
137                  << "pick a target.\n";
138        return 1;
139      }
140    }
141
142    // Package up features to be passed to target/subtarget
143    std::string FeaturesStr;
144    if (MCPU.size() || MAttrs.size()) {
145      SubtargetFeatures Features;
146      Features.setCPU(MCPU);
147      for (unsigned i = 0; i != MAttrs.size(); ++i)
148        Features.AddFeature(MAttrs[i]);
149      FeaturesStr = Features.getString();
150    }
151
152    std::auto_ptr<TargetMachine> target(MArch->CtorFn(mod, 0, FeaturesStr));
153    assert(target.get() && "Could not allocate target machine!");
154    TargetMachine &Target = *target.get();
155    const TargetData &TD = Target.getTargetData();
156
157    // Build up all of the passes that we want to do to the module...
158    PassManager Passes;
159    Passes.add(new TargetData(TD));
160
161    // Create a new pass for each one specified on the command line
162    for (unsigned i = 0; i < LLCPassList.size(); ++i) {
163      const PassInfo *aPass = LLCPassList[i];
164
165      if (aPass->getNormalCtor()) {
166        Pass *P = aPass->getNormalCtor()();
167        Passes.add(P);
168      } else {
169        std::cerr << argv[0] << ": cannot create pass: "
170                  << aPass->getPassName() << "\n";
171      }
172    }
173
174#ifndef NDEBUG
175    if(!NoVerify)
176      Passes.add(createVerifierPass());
177#endif
178
179    // Figure out where we are going to send the output...
180    std::ostream *Out = 0;
181    if (OutputFilename != "") {
182      if (OutputFilename != "-") {
183        // Specified an output filename?
184        if (!Force && std::ifstream(OutputFilename.c_str())) {
185          // If force is not specified, make sure not to overwrite a file!
186          std::cerr << argv[0] << ": error opening '" << OutputFilename
187                    << "': file exists!\n"
188                    << "Use -f command line argument to force output\n";
189          return 1;
190        }
191        Out = new std::ofstream(OutputFilename.c_str());
192
193        // Make sure that the Out file gets unlinked from the disk if we get a
194        // SIGINT
195        sys::RemoveFileOnSignal(sys::Path(OutputFilename));
196      } else {
197        Out = &std::cout;
198      }
199    } else {
200      if (InputFilename == "-") {
201        OutputFilename = "-";
202        Out = &std::cout;
203      } else {
204        OutputFilename = GetFileNameRoot(InputFilename);
205
206        switch (FileType) {
207        case TargetMachine::AssemblyFile:
208          if (MArch->Name[0] != 'c' || MArch->Name[1] != 0)  // not CBE
209            OutputFilename += ".s";
210          else
211            OutputFilename += ".cbe.c";
212          break;
213        case TargetMachine::ObjectFile:
214          OutputFilename += ".o";
215          break;
216        case TargetMachine::DynamicLibrary:
217          OutputFilename += LTDL_SHLIB_EXT;
218          break;
219        }
220
221        if (!Force && std::ifstream(OutputFilename.c_str())) {
222          // If force is not specified, make sure not to overwrite a file!
223          std::cerr << argv[0] << ": error opening '" << OutputFilename
224                    << "': file exists!\n"
225                    << "Use -f command line argument to force output\n";
226          return 1;
227        }
228
229        Out = new std::ofstream(OutputFilename.c_str());
230        if (!Out->good()) {
231          std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
232          delete Out;
233          return 1;
234        }
235
236        // Make sure that the Out file gets unlinked from the disk if we get a
237        // SIGINT
238        sys::RemoveFileOnSignal(sys::Path(OutputFilename));
239      }
240    }
241
242    // Ask the target to add backend passes as necessary.
243    if (Target.addPassesToEmitFile(Passes, *Out, FileType, Fast)) {
244      std::cerr << argv[0] << ": target '" << Target.getName()
245                << "' does not support generation of this file type!\n";
246      if (Out != &std::cout) delete Out;
247      // And the Out file is empty and useless, so remove it now.
248      sys::Path(OutputFilename).eraseFromDisk();
249      return 1;
250    } else {
251      // Run our queue of passes all at once now, efficiently.
252      Passes.run(*M.get());
253    }
254
255    // Delete the ostream if it's not a stdout stream
256    if (Out != &std::cout) delete Out;
257
258    return 0;
259  } catch (const std::string& msg) {
260    std::cerr << argv[0] << ": " << msg << "\n";
261  } catch (...) {
262    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
263  }
264  return 1;
265}
266