llc.cpp revision b5881f126d4baab41dc7efb2824a53601ef167b0 
1//===-- llc.cpp - Implement the LLVM Compiler -----------------------------===//
2//
3// This is the llc compiler driver.
4//
5//===----------------------------------------------------------------------===//
6
7#include "llvm/Bytecode/Reader.h"
8#include "llvm/Target/TargetMachineImpls.h"
9#include "llvm/Target/TargetMachine.h"
10#include "llvm/Transforms/Instrumentation.h"
11#include "llvm/Transforms/Scalar.h"
12#include "llvm/Transforms/Utils/Linker.h"
13#include "llvm/Assembly/PrintModulePass.h"
14#include "llvm/Bytecode/WriteBytecodePass.h"
15#include "llvm/Transforms/IPO.h"
16#include "llvm/Module.h"
17#include "llvm/PassManager.h"
18#include "llvm/Pass.h"
19#include "llvm/Support/PassNameParser.h"
20#include "Support/CommandLine.h"
21#include "Support/Signals.h"
22#include <memory>
23#include <fstream>
24
25//------------------------------------------------------------------------------
26// Option declarations for LLC.
27//------------------------------------------------------------------------------
28
29// Make all registered optimization passes available to llc.  These passes
30// will all be run before the simplification and lowering steps used by the
31// back-end code generator, and will be run in the order specified on the
32// command line. The OptimizationList is automatically populated with
33// registered Passes by the PassNameParser.
34//
35static cl::list<const PassInfo*, bool,
36                FilteredPassNameParser<PassInfo::Optimization> >
37OptimizationList(cl::desc("Optimizations available:"));
38
39
40// General options for llc.  Other pass-specific options are specified
41// within the corresponding llc passes, and target-specific options
42// and back-end code generation options are specified with the target machine.
43//
44static cl::opt<std::string>
45InputFilename(cl::Positional, cl::desc("<input bytecode>"), cl::init("-"));
46
47static cl::opt<std::string>
48OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
49
50static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
51
52static cl::opt<bool>
53DumpAsm("d", cl::desc("Print bytecode before native code generation"),
54        cl::Hidden);
55
56static cl::opt<std::string>
57TraceLibPath("tracelibpath", cl::desc("Path to libinstr for trace code"),
58             cl::value_desc("directory"), cl::Hidden);
59
60
61// flags set from -tracem and -trace options to control tracing
62static bool TraceFunctions   = false;
63static bool TraceBasicBlocks = false;
64
65
66// GetFileNameRoot - Helper function to get the basename of a filename...
67static inline std::string
68GetFileNameRoot(const std::string &InputFilename)
69{
70  std::string IFN = InputFilename;
71  std::string outputFilename;
72  int Len = IFN.length();
73  if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
74    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
75  } else {
76    outputFilename = IFN;
77  }
78  return outputFilename;
79}
80
81static bool
82insertTraceCodeFor(Module &M)
83{
84  PassManager Passes;
85
86  // Insert trace code in all functions in the module
87  if (TraceBasicBlocks)
88    Passes.add(createTraceValuesPassForBasicBlocks());
89  else if (TraceFunctions)
90    Passes.add(createTraceValuesPassForFunction());
91  else
92    return false;
93
94  // Eliminate duplication in constant pool
95  Passes.add(createConstantMergePass());
96
97  // Run passes to insert and clean up trace code...
98  Passes.run(M);
99
100  std::string ErrorMessage;
101
102  // Load the module that contains the runtime helper routines neccesary for
103  // pointer hashing and stuff...  link this module into the program if possible
104  //
105  Module *TraceModule = ParseBytecodeFile(TraceLibPath+"libinstr.bc");
106
107  // Check if the TraceLibPath contains a valid module.  If not, try to load
108  // the module from the current LLVM-GCC install directory.  This is kindof
109  // a hack, but allows people to not HAVE to have built the library.
110  //
111  if (TraceModule == 0)
112    TraceModule = ParseBytecodeFile("/home/vadve/lattner/cvs/gcc_install/lib/"
113                                    "gcc-lib/llvm/3.1/libinstr.bc");
114
115  // If we still didn't get it, cancel trying to link it in...
116  if (TraceModule == 0)
117    std::cerr <<"WARNING: couldn't load trace routines to link into program!\n";
118  else
119    {
120      // Link in the trace routines... if this fails, don't panic, because the
121      // compile should still succeed, but the native linker will probably fail.
122      //
123      std::auto_ptr<Module> TraceRoutines(TraceModule);
124      if (LinkModules(&M, TraceRoutines.get(), &ErrorMessage))
125        std::cerr << "WARNING: Error linking in trace routines: "
126                  << ErrorMessage << "\n";
127    }
128
129  // Write out the module with tracing code just before code generation
130  assert (InputFilename != "-"
131          && "Cannot write out traced bytecode when reading input from stdin");
132  std::string TraceFilename = GetFileNameRoot(InputFilename) + ".trace.bc";
133
134  std::ofstream Out(TraceFilename.c_str());
135  if (!Out.good())
136    std::cerr << "Error opening '" << TraceFilename
137              << "'!: Skipping output of trace code as bytecode\n";
138  else
139    {
140      std::cerr << "Emitting trace code to '" << TraceFilename
141                << "' for comparison...\n";
142      WriteBytecodeToFile(&M, Out);
143    }
144
145  return true;
146}
147
148// Making tracing a module pass so the entire module with tracing
149// can be written out before continuing.
150struct InsertTracingCodePass: public Pass {
151  virtual bool run(Module &M) {
152    return insertTraceCodeFor(M);
153  }
154};
155
156
157//===---------------------------------------------------------------------===//
158// Function main()
159//
160// Entry point for the llc compiler.
161//===---------------------------------------------------------------------===//
162
163int
164main(int argc, char **argv)
165{
166  cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
167
168  // Allocate a target... in the future this will be controllable on the
169  // command line.
170  std::auto_ptr<TargetMachine> target(allocateSparcTargetMachine());
171  assert(target.get() && "Could not allocate target machine!");
172
173  TargetMachine &Target = *target.get();
174  const TargetData &TD = Target.getTargetData();
175
176  // Load the module to be compiled...
177  std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
178  if (M.get() == 0)
179    {
180      std::cerr << argv[0] << ": bytecode didn't read correctly.\n";
181      return 1;
182    }
183
184  // Build up all of the passes that we want to do to the module...
185  PassManager Passes;
186
187  Passes.add(new TargetData("llc", TD.isLittleEndian(), TD.getSubWordDataSize(),
188                            TD.getIntegerRegSize(), TD.getPointerSize(),
189                            TD.getPointerAlignment()));
190
191  // Create a new optimization pass for each one specified on the command line
192  // Deal specially with tracing passes, which must be run differently than opt.
193  //
194  for (unsigned i = 0; i < OptimizationList.size(); ++i)
195    {
196      const PassInfo *Opt = OptimizationList[i];
197
198      if (std::string(Opt->getPassArgument()) == "trace")
199        TraceFunctions = !(TraceBasicBlocks = true);
200      else if (std::string(Opt->getPassArgument()) == "tracem")
201        TraceFunctions = !(TraceBasicBlocks = false);
202      else
203        { // handle other passes as normal optimization passes
204          if (Opt->getNormalCtor())
205            Passes.add(Opt->getNormalCtor()());
206          else if (Opt->getTargetCtor())
207            Passes.add(Opt->getTargetCtor()(Target));
208          else
209            std::cerr << argv[0] << ": cannot create pass: "
210                      << Opt->getPassName() << "\n";
211        }
212    }
213
214  // Run tracing passes after other optimization passes and before llc passes.
215  if (TraceFunctions || TraceBasicBlocks)
216    Passes.add(new InsertTracingCodePass);
217
218  // Decompose multi-dimensional refs into a sequence of 1D refs
219  Passes.add(createDecomposeMultiDimRefsPass());
220
221  // Replace malloc and free instructions with library calls.
222  // Do this after tracing until lli implements these lib calls.
223  // For now, it will emulate malloc and free internally.
224  Passes.add(createLowerAllocationsPass());
225
226  // If LLVM dumping after transformations is requested, add it to the pipeline
227  if (DumpAsm)
228    Passes.add(new PrintFunctionPass("Code after xformations: \n", &std::cerr));
229
230  // Strip all of the symbols from the bytecode so that it will be smaller...
231  Passes.add(createSymbolStrippingPass());
232
233  // Figure out where we are going to send the output...
234  std::ostream *Out = 0;
235  if (OutputFilename != "")
236    {   // Specified an output filename?
237      if (!Force && std::ifstream(OutputFilename.c_str())) {
238        // If force is not specified, make sure not to overwrite a file!
239        std::cerr << argv[0] << ": error opening '" << OutputFilename
240                  << "': file exists!\n"
241                  << "Use -f command line argument to force output\n";
242        return 1;
243      }
244      Out = new std::ofstream(OutputFilename.c_str());
245
246      // Make sure that the Out file gets unlink'd from the disk if we get a
247      // SIGINT
248      RemoveFileOnSignal(OutputFilename);
249    }
250  else
251    {
252      if (InputFilename == "-")
253        {
254          OutputFilename = "-";
255          Out = &std::cout;
256        }
257      else
258        {
259          std::string OutputFilename = GetFileNameRoot(InputFilename);
260          OutputFilename += ".s";
261
262          if (!Force && std::ifstream(OutputFilename.c_str()))
263            {
264              // If force is not specified, make sure not to overwrite a file!
265              std::cerr << argv[0] << ": error opening '" << OutputFilename
266                        << "': file exists!\n"
267                        << "Use -f command line argument to force output\n";
268              return 1;
269            }
270
271          Out = new std::ofstream(OutputFilename.c_str());
272          if (!Out->good())
273            {
274              std::cerr << argv[0] << ": error opening " << OutputFilename
275                        << "!\n";
276              delete Out;
277              return 1;
278            }
279
280          // Make sure that the Out file gets unlink'd from the disk if we get a
281          // SIGINT
282          RemoveFileOnSignal(OutputFilename);
283        }
284    }
285
286  // Ask the target to add backend passes as neccesary
287  if (Target.addPassesToEmitAssembly(Passes, *Out)) {
288    std::cerr << argv[0] << ": target '" << Target.getName()
289              << " does not support static compilation!\n";
290  } else {
291    // Run our queue of passes all at once now, efficiently.
292    Passes.run(*M.get());
293  }
294
295  // Delete the ostream if it's not a stdout stream
296  if (Out != &std::cout) delete Out;
297
298  return 0;
299}
300