llc.cpp revision 90c5b3d753cef1f731dbb66f151da75af1f024b4 
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/Optimizations/Normalize.h"
9#include "llvm/Target/Sparc.h"
10#include "llvm/Target/TargetMachine.h"
11#include "llvm/Transforms/Instrumentation/TraceValues.h"
12#include "llvm/Support/CommandLine.h"
13#include "llvm/Module.h"
14#include "llvm/Method.h"
15#include <memory>
16#include <string>
17#include <fstream>
18
19cl::String InputFilename ("", "Input filename", cl::NoFlags, "-");
20cl::String OutputFilename("o", "Output filename", cl::NoFlags, "");
21cl::Flag   Force         ("f", "Overwrite output files", cl::NoFlags, false);
22cl::Flag   DumpAsm       ("d", "Print bytecode before native code generation", cl::Hidden,false);
23cl::Flag   DoNotEmitAssembly("noasm", "Do not emit assembly code", cl::Hidden, false);
24cl::Flag   TraceBBValues ("trace",
25                          "Trace values at basic block and method exits",
26                          cl::NoFlags, false);
27cl::Flag   TraceMethodValues("tracem", "Trace values only at method exits",
28                             cl::NoFlags, false);
29
30#include "llvm/Assembly/Writer.h"   // For DumpAsm
31
32//-------------------------- Internal Functions ------------------------------//
33
34
35/////
36// TODO: Remove to external file.... When Chris gets back he'll do it
37/////
38#include "llvm/DerivedTypes.h"
39#include "llvm/iMemory.h"
40#include "llvm/iOther.h"
41#include "llvm/SymbolTable.h"
42
43
44Method *MallocMeth = 0, *FreeMeth = 0;
45
46// InsertMallocFreeDecls - Insert an external declaration for malloc and an
47// external declaration for free for use by the ReplaceMallocFree function.
48//
49static void InsertMallocFreeDecls(Module *M) {
50  const MethodType *MallocType =
51    MethodType::get(PointerType::get(Type::UByteTy),
52                    vector<const Type*>(1, Type::UIntTy), false);
53
54  SymbolTable *SymTab = M->getSymbolTableSure();
55
56  // Check for a definition of malloc
57  if (Value *V = SymTab->lookup(PointerType::get(MallocType), "malloc")) {
58    MallocMeth = cast<Method>(V);      // Yup, got it
59  } else {                             // Nope, add one
60    M->getMethodList().push_back(MallocMeth = new Method(MallocType, "malloc"));
61  }
62
63  const MethodType *FreeType =
64    MethodType::get(Type::VoidTy,
65                    vector<const Type*>(1, PointerType::get(Type::UByteTy)),
66		    false);
67
68  // Check for a definition of free
69  if (Value *V = SymTab->lookup(PointerType::get(FreeType), "free")) {
70    FreeMeth = cast<Method>(V);      // Yup, got it
71  } else {                             // Nope, add one
72    M->getMethodList().push_back(FreeMeth = new Method(FreeType, "free"));
73  }
74}
75
76
77static void ReplaceMallocFree(Method *M, const TargetData &DataLayout) {
78  assert(MallocMeth && FreeMeth && M && "Must call InsertMallocFreeDecls!");
79
80  // Loop over all of the instructions, looking for malloc or free instructions
81  for (Method::iterator BBI = M->begin(), BBE = M->end(); BBI != BBE; ++BBI) {
82    BasicBlock *BB = *BBI;
83    for (unsigned i = 0; i < BB->size(); ++i) {
84      BasicBlock::InstListType &BBIL = BB->getInstList();
85      if (MallocInst *MI = dyn_cast<MallocInst>(*(BBIL.begin()+i))) {
86        BBIL.remove(BBIL.begin()+i);   // remove the malloc instr...
87
88        const Type *AllocTy = cast<PointerType>(MI->getType())->getValueType();
89
90        // If the user is allocating an unsized array with a dynamic size arg,
91        // start by getting the size of one element.
92        //
93        if (const ArrayType *ATy = dyn_cast<ArrayType>(AllocTy))
94          if (ATy->isUnsized()) AllocTy = ATy->getElementType();
95
96        // Get the number of bytes to be allocated for one element of the
97        // requested type...
98        unsigned Size = DataLayout.getTypeSize(AllocTy);
99
100        // malloc(type) becomes sbyte *malloc(constint)
101        Value *MallocArg = ConstPoolUInt::get(Type::UIntTy, Size);
102        if (MI->getNumOperands() && Size == 1) {
103          MallocArg = MI->getOperand(0);         // Operand * 1 = Operand
104        } else if (MI->getNumOperands()) {
105          // Multiply it by the array size if neccesary...
106          MallocArg = BinaryOperator::create(Instruction::Mul,MI->getOperand(0),
107                                             MallocArg);
108          BBIL.insert(BBIL.begin()+i++, cast<Instruction>(MallocArg));
109        }
110
111        // Create the call to Malloc...
112        CallInst *MCall = new CallInst(MallocMeth,
113                                       vector<Value*>(1, MallocArg));
114        BBIL.insert(BBIL.begin()+i, MCall);
115
116        // Create a cast instruction to convert to the right type...
117        CastInst *MCast = new CastInst(MCall, MI->getType());
118        BBIL.insert(BBIL.begin()+i+1, MCast);
119
120        // Replace all uses of the old malloc inst with the cast inst
121        MI->replaceAllUsesWith(MCast);
122        delete MI;                          // Delete the malloc inst
123      } else if (FreeInst *FI = dyn_cast<FreeInst>(*(BBIL.begin()+i))) {
124        BBIL.remove(BB->getInstList().begin()+i);
125
126        // Cast the argument to free into a ubyte*...
127        CastInst *MCast = new CastInst(FI->getOperand(0),
128                                       PointerType::get(Type::UByteTy));
129        BBIL.insert(BBIL.begin()+i, MCast);
130
131        // Insert a call to the free function...
132        CallInst *FCall = new CallInst(FreeMeth,
133                                       vector<Value*>(1, MCast));
134        BBIL.insert(BBIL.begin()+i+1, FCall);
135
136        // Delete the old free instruction
137        delete FI;
138      }
139    }
140  }
141}
142
143
144// END TODO: Remove to external file....
145
146static void NormalizeMethod(Method *M) {
147  NormalizePhiConstantArgs(M);
148}
149
150inline string
151GetFileNameRoot(const string& InputFilename)
152{
153  string IFN = InputFilename;
154  string outputFilename;
155  int Len = IFN.length();
156  if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
157    outputFilename = string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
158  } else {
159    outputFilename = IFN;   // Append a .s to it
160  }
161  return outputFilename;
162}
163
164inline string
165GetTraceAssemblyFileName(const string& inFilename)
166{
167  assert(inFilename != "-" && "files on stdin not supported with tracing");
168  string traceFileName = GetFileNameRoot(inFilename);
169  traceFileName += ".trace.ll";
170  return traceFileName;
171}
172
173//===---------------------------------------------------------------------===//
174// Function PreprocessModule()
175//
176// Normalization to simplify later passes.
177//===---------------------------------------------------------------------===//
178
179int
180PreprocessModule(Module* module)
181{
182  InsertMallocFreeDecls(module);
183
184  for (Module::const_iterator MI=module->begin(); MI != module->end(); ++MI)
185    if (! (*MI)->isExternal())
186      NormalizeMethod(*MI);
187
188  return 0;
189}
190
191
192//===---------------------------------------------------------------------===//
193// Function OptimizeModule()
194//
195// Module optimization.
196//===---------------------------------------------------------------------===//
197
198int
199OptimizeModule(Module* module)
200{
201  return 0;
202}
203
204
205//===---------------------------------------------------------------------===//
206// Function GenerateCodeForModule()
207//
208// Native code generation for a specified target.
209//===---------------------------------------------------------------------===//
210
211int
212GenerateCodeForModule(Module* module, TargetMachine* target)
213{
214  // Since any transformation pass may introduce external function decls
215  // into the method list, find current methods first and then walk only those.
216  //
217  vector<Method*> initialMethods(module->begin(), module->end());
218
219
220  // Replace malloc and free instructions with library calls
221  //
222  for (unsigned i=0, N = initialMethods.size(); i < N; i++)
223    if (! initialMethods[i]->isExternal())
224      ReplaceMallocFree(initialMethods[i], target->DataLayout);
225
226
227  // Insert trace code to assist debugging
228  //
229  if (TraceBBValues || TraceMethodValues)
230    {
231      // Insert trace code in all methods in the module
232      for (unsigned i=0, N = initialMethods.size(); i < N; i++)
233        if (! initialMethods[i]->isExternal())
234          InsertCodeToTraceValues(initialMethods[i], TraceBBValues,
235                                  TraceBBValues || TraceMethodValues);
236
237      // Then write the module with tracing code out in assembly form
238      string traceFileName = GetTraceAssemblyFileName(InputFilename);
239      ofstream* ofs = new ofstream(traceFileName.c_str(),
240                                   (Force ? 0 : ios::noreplace)|ios::out);
241      if (!ofs->good()) {
242        cerr << "Error opening " << traceFileName << "!\n";
243        delete ofs;
244        return 1;
245      }
246      WriteToAssembly(module, *ofs);
247      delete ofs;
248    }
249
250
251  // Generate native target code for all methods
252  //
253  for (unsigned i=0, N = initialMethods.size(); i < N; i++)
254    if (! initialMethods[i]->isExternal())
255      {
256        if (DumpAsm)
257          cerr << "Method after xformations: \n" << initialMethods[i];
258
259        if (target->compileMethod(initialMethods[i])) {
260          cerr << "Error compiling " << InputFilename << "!\n";
261          return 1;
262        }
263      }
264
265  return 0;
266}
267
268
269//===---------------------------------------------------------------------===//
270// Function EmitAssemblyForModule()
271//
272// Write assembly code to specified output file; <ModuleName>.s by default.
273//===---------------------------------------------------------------------===//
274
275int
276EmitAssemblyForModule(Module* module, TargetMachine* target)
277{
278  // Figure out where we are going to send the output...
279  ostream *Out = 0;
280  if (OutputFilename != "") {   // Specified an output filename?
281    Out = new ofstream(OutputFilename.c_str(),
282                       (Force ? 0 : ios::noreplace)|ios::out);
283  } else {
284    if (InputFilename == "-") {
285      OutputFilename = "-";
286      Out = &cout;
287    } else {
288      string OutputFilename = GetFileNameRoot(InputFilename);
289      OutputFilename += ".s";
290      Out = new ofstream(OutputFilename.c_str(),
291                         (Force ? 0 : ios::noreplace)|ios::out);
292      if (!Out->good()) {
293        cerr << "Error opening " << OutputFilename << "!\n";
294        delete Out;
295        return 1;
296      }
297    }
298  }
299
300  // Emit the output...
301  target->emitAssembly(module, *Out);
302
303  if (Out != &cout) delete Out;
304
305  return 0;
306}
307
308
309//===---------------------------------------------------------------------===//
310// Function main()
311//
312// Entry point for the llc compiler.
313//===---------------------------------------------------------------------===//
314
315int
316main(int argc, char **argv)
317{
318  // Parse command line options...
319  cl::ParseCommandLineOptions(argc, argv, " llvm system compiler\n");
320
321  // Allocate a target... in the future this will be controllable on the
322  // command line.
323  auto_ptr<TargetMachine> target(allocateSparcTargetMachine());
324
325  // Load the module to be compiled...
326  auto_ptr<Module> M(ParseBytecodeFile(InputFilename));
327  if (M.get() == 0) {
328    cerr << "bytecode didn't read correctly.\n";
329    return 1;
330  }
331
332  if (PreprocessModule(M.get())) return 1;
333
334  if (OptimizeModule(M.get())) return 1;
335
336  if (GenerateCodeForModule(M.get(), target.get())) return 1;
337
338  if (!DoNotEmitAssembly)
339    if (EmitAssemblyForModule(M.get(), target.get())) return 1;
340
341  return 0;
342}
343
344