llc.cpp revision 452fea997232437902385e88366482b01957eeef 
1//===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
2//
3// This is the llc code generator.
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/Scalar.h"
11#include "llvm/Module.h"
12#include "llvm/PassManager.h"
13#include "llvm/Pass.h"
14#include "Support/CommandLine.h"
15#include "Support/Signals.h"
16#include <memory>
17#include <fstream>
18
19// General options for llc.  Other pass-specific options are specified
20// within the corresponding llc passes, and target-specific options
21// and back-end code generation options are specified with the target machine.
22//
23static cl::opt<std::string>
24InputFilename(cl::Positional, cl::desc("<input bytecode>"), cl::init("-"));
25
26static cl::opt<std::string>
27OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
28
29static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
30
31enum ArchName { noarch, x86, Sparc };
32
33static cl::opt<ArchName>
34Arch("march", cl::desc("Architecture to generate assembly for:"), cl::Prefix,
35     cl::values(clEnumVal(x86, "  IA-32 (Pentium and above)"),
36                clEnumValN(Sparc, "sparc", "  SPARC V9"),
37		0),
38     cl::init(noarch));
39
40// GetFileNameRoot - Helper function to get the basename of a filename...
41static inline std::string
42GetFileNameRoot(const std::string &InputFilename)
43{
44  std::string IFN = InputFilename;
45  std::string outputFilename;
46  int Len = IFN.length();
47  if ((Len > 2) &&
48      IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
49    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
50  } else {
51    outputFilename = IFN;
52  }
53  return outputFilename;
54}
55
56
57// main - Entry point for the llc compiler.
58//
59int main(int argc, char **argv) {
60  cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
61
62  // Load the module to be compiled...
63  std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
64  if (M.get() == 0) {
65    std::cerr << argv[0] << ": bytecode didn't read correctly.\n";
66    return 1;
67  }
68  Module &mod = *M.get();
69
70  // Allocate target machine.  First, check whether the user has
71  // explicitly specified an architecture to compile for.
72  TargetMachine* (*TargetMachineAllocator)(const Module&) = 0;
73  switch (Arch) {
74  case x86:
75    TargetMachineAllocator = allocateX86TargetMachine;
76    break;
77  case Sparc:
78    TargetMachineAllocator = allocateSparcTargetMachine;
79    break;
80  default:
81    // Decide what the default target machine should be, by looking at
82    // the module. This heuristic (ILP32, LE -> IA32; LP64, BE ->
83    // SPARCV9) is kind of gross, but it will work until we have more
84    // sophisticated target information to work from.
85    if (mod.getEndianness()  == Module::LittleEndian &&
86        mod.getPointerSize() == Module::Pointer32) {
87      TargetMachineAllocator = allocateX86TargetMachine;
88    } else if (mod.getEndianness()  == Module::BigEndian &&
89               mod.getPointerSize() == Module::Pointer64) {
90      TargetMachineAllocator = allocateSparcTargetMachine;
91    } else {
92      // If the module is target independent, favor a target which matches the
93      // current build system.
94#if defined(i386) || defined(__i386__) || defined(__x86__)
95      TargetMachineAllocator = allocateX86TargetMachine;
96#elif defined(sparc) || defined(__sparc__) || defined(__sparcv9)
97      TargetMachineAllocator = allocateSparcTargetMachine;
98#else
99      std::cerr << argv[0] << ": module does not specify a target to use.  "
100                << "You must use the -march option.\n";
101      return 1;
102#endif
103    }
104    break;
105  }
106  std::auto_ptr<TargetMachine> target(TargetMachineAllocator(mod));
107  assert(target.get() && "Could not allocate target machine!");
108  TargetMachine &Target = *target.get();
109  const TargetData &TD = Target.getTargetData();
110
111  // Build up all of the passes that we want to do to the module...
112  PassManager Passes;
113
114  Passes.add(new TargetData("llc", TD.isLittleEndian(), TD.getPointerSize(),
115                            TD.getPointerAlignment(), TD.getDoubleAlignment()));
116
117  // Figure out where we are going to send the output...
118  std::ostream *Out = 0;
119  if (OutputFilename != "") {
120    if (OutputFilename != "-") {
121      // Specified an output filename?
122      if (!Force && std::ifstream(OutputFilename.c_str())) {
123	// If force is not specified, make sure not to overwrite a file!
124	std::cerr << argv[0] << ": error opening '" << OutputFilename
125		  << "': file exists!\n"
126		  << "Use -f command line argument to force output\n";
127	return 1;
128      }
129      Out = new std::ofstream(OutputFilename.c_str());
130
131      // Make sure that the Out file gets unlinked from the disk if we get a
132      // SIGINT
133      RemoveFileOnSignal(OutputFilename);
134    } else {
135      Out = &std::cout;
136    }
137  } else {
138    if (InputFilename == "-") {
139      OutputFilename = "-";
140      Out = &std::cout;
141    } else {
142      OutputFilename = GetFileNameRoot(InputFilename);
143      OutputFilename += ".s";
144
145      if (!Force && std::ifstream(OutputFilename.c_str())) {
146        // If force is not specified, make sure not to overwrite a file!
147        std::cerr << argv[0] << ": error opening '" << OutputFilename
148                  << "': file exists!\n"
149                  << "Use -f command line argument to force output\n";
150        return 1;
151      }
152
153      Out = new std::ofstream(OutputFilename.c_str());
154      if (!Out->good()) {
155        std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
156        delete Out;
157        return 1;
158      }
159
160      // Make sure that the Out file gets unlinked from the disk if we get a
161      // SIGINT
162      RemoveFileOnSignal(OutputFilename);
163    }
164  }
165
166  // Ask the target to add backend passes as necessary
167  if (Target.addPassesToEmitAssembly(Passes, *Out)) {
168    std::cerr << argv[0] << ": target '" << Target.getName()
169              << "' does not support static compilation!\n";
170    if (Out != &std::cout) delete Out;
171    // And the Out file is empty and useless, so remove it now.
172    std::remove(OutputFilename.c_str());
173    return 1;
174  } else {
175    // Run our queue of passes all at once now, efficiently.
176    Passes.run(*M.get());
177  }
178
179  // Delete the ostream if it's not a stdout stream
180  if (Out != &std::cout) delete Out;
181
182  return 0;
183}
184