MachineFunction.cpp revision c0b9dc5be79f009d260edb5cd5e1d8346587aaa2 
1//===-- MachineFunction.cpp -----------------------------------------------===//
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// Collect native machine code information for a function.  This allows
11// target-specific information about the generated code to be stored with each
12// function.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/CodeGen/MachineFunctionPass.h"
17#include "llvm/CodeGen/MachineInstr.h"
18#include "llvm/CodeGen/MachineCodeForInstruction.h"
19#include "llvm/CodeGen/SSARegMap.h"
20#include "llvm/CodeGen/MachineFunctionInfo.h"
21#include "llvm/CodeGen/MachineFrameInfo.h"
22#include "llvm/CodeGen/MachineConstantPool.h"
23#include "llvm/CodeGen/Passes.h"
24#include "llvm/Target/TargetMachine.h"
25#include "llvm/Target/TargetFrameInfo.h"
26#include "llvm/Target/TargetCacheInfo.h"
27#include "llvm/Function.h"
28#include "llvm/iOther.h"
29using namespace llvm;
30
31static AnnotationID MF_AID(
32                 AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
33
34
35namespace {
36  struct Printer : public MachineFunctionPass {
37    std::ostream *OS;
38    const std::string Banner;
39
40    Printer (std::ostream *_OS, const std::string &_Banner) :
41      OS (_OS), Banner (_Banner) { }
42
43    const char *getPassName() const { return "MachineFunction Printer"; }
44
45    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
46      AU.setPreservesAll();
47    }
48
49    bool runOnMachineFunction(MachineFunction &MF) {
50      (*OS) << Banner;
51      MF.print (*OS);
52      return false;
53    }
54  };
55}
56
57/// Returns a newly-created MachineFunction Printer pass. The default output
58/// stream is std::cerr; the default banner is empty.
59///
60FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
61                                                     const std::string &Banner) {
62  return new Printer(OS, Banner);
63}
64
65//===---------------------------------------------------------------------===//
66// MachineFunction implementation
67//===---------------------------------------------------------------------===//
68
69MachineFunction::MachineFunction(const Function *F,
70                                 const TargetMachine &TM)
71  : Annotation(MF_AID), Fn(F), Target(TM) {
72  SSARegMapping = new SSARegMap();
73  MFInfo = new MachineFunctionInfo(*this);
74  FrameInfo = new MachineFrameInfo();
75  ConstantPool = new MachineConstantPool();
76}
77
78MachineFunction::~MachineFunction() {
79  delete SSARegMapping;
80  delete MFInfo;
81  delete FrameInfo;
82  delete ConstantPool;
83}
84
85void MachineFunction::dump() const { print(std::cerr); }
86
87void MachineFunction::print(std::ostream &OS) const {
88  OS << "\n" << *(Value*)Fn->getFunctionType() << " \"" << Fn->getName()
89     << "\"\n";
90
91  // Print Frame Information
92  getFrameInfo()->print(*this, OS);
93
94  // Print Constant Pool
95  getConstantPool()->print(OS);
96
97  for (const_iterator BB = begin(); BB != end(); ++BB) {
98    const BasicBlock *LBB = BB->getBasicBlock();
99    OS << "\n" << LBB->getName() << " (" << (const void*)LBB << "):\n";
100    for (MachineBasicBlock::const_iterator I = BB->begin(); I != BB->end();++I){
101      OS << "\t";
102      I->print(OS, Target);
103    }
104  }
105  OS << "\nEnd function \"" << Fn->getName() << "\"\n\n";
106}
107
108
109// The next two methods are used to construct and to retrieve
110// the MachineCodeForFunction object for the given function.
111// construct() -- Allocates and initializes for a given function and target
112// get()       -- Returns a handle to the object.
113//                This should not be called before "construct()"
114//                for a given Function.
115//
116MachineFunction&
117MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
118{
119  assert(Fn->getAnnotation(MF_AID) == 0 &&
120         "Object already exists for this function!");
121  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
122  Fn->addAnnotation(mcInfo);
123  return *mcInfo;
124}
125
126void MachineFunction::destruct(const Function *Fn) {
127  bool Deleted = Fn->deleteAnnotation(MF_AID);
128  assert(Deleted && "Machine code did not exist for function!");
129}
130
131MachineFunction& MachineFunction::get(const Function *F)
132{
133  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
134  assert(mc && "Call construct() method first to allocate the object");
135  return *mc;
136}
137
138void MachineFunction::clearSSARegMap() {
139  delete SSARegMapping;
140  SSARegMapping = 0;
141}
142
143//===----------------------------------------------------------------------===//
144//  MachineFrameInfo implementation
145//===----------------------------------------------------------------------===//
146
147/// CreateStackObject - Create a stack object for a value of the specified type.
148///
149int MachineFrameInfo::CreateStackObject(const Type *Ty, const TargetData &TD) {
150  return CreateStackObject(TD.getTypeSize(Ty), TD.getTypeAlignment(Ty));
151}
152
153int MachineFrameInfo::CreateStackObject(const TargetRegisterClass *RC) {
154  return CreateStackObject(RC->getSize(), RC->getAlignment());
155}
156
157
158void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
159  int ValOffset = MF.getTarget().getFrameInfo().getOffsetOfLocalArea();
160
161  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
162    const StackObject &SO = Objects[i];
163    OS << "  <fi #" << (int)(i-NumFixedObjects) << "> is ";
164    if (SO.Size == 0)
165      OS << "variable sized";
166    else
167      OS << SO.Size << " byte" << (SO.Size != 1 ? "s" : " ");
168
169    if (i < NumFixedObjects)
170      OS << " fixed";
171    if (i < NumFixedObjects || SO.SPOffset != -1) {
172      int Off = SO.SPOffset + ValOffset;
173      OS << " at location [SP";
174      if (Off > 0)
175	OS << "+" << Off;
176      else if (Off < 0)
177	OS << Off;
178      OS << "]";
179    }
180    OS << "\n";
181  }
182
183  if (HasVarSizedObjects)
184    OS << "  Stack frame contains variable sized objects\n";
185}
186
187void MachineFrameInfo::dump(const MachineFunction &MF) const {
188  print(MF, std::cerr);
189}
190
191
192//===----------------------------------------------------------------------===//
193//  MachineConstantPool implementation
194//===----------------------------------------------------------------------===//
195
196void MachineConstantPool::print(std::ostream &OS) const {
197  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
198    OS << "  <cp #" << i << "> is" << *(Value*)Constants[i] << "\n";
199}
200
201void MachineConstantPool::dump() const { print(std::cerr); }
202
203//===----------------------------------------------------------------------===//
204//  MachineFunctionInfo implementation
205//===----------------------------------------------------------------------===//
206
207static unsigned
208ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
209                           unsigned &maxOptionalNumArgs)
210{
211  const TargetFrameInfo &frameInfo = target.getFrameInfo();
212
213  unsigned maxSize = 0;
214
215  for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
216    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
217      if (const CallInst *callInst = dyn_cast<CallInst>(I))
218        {
219          unsigned numOperands = callInst->getNumOperands() - 1;
220          int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
221          if (numExtra <= 0)
222            continue;
223
224          unsigned sizeForThisCall;
225          if (frameInfo.argsOnStackHaveFixedSize())
226            {
227              int argSize = frameInfo.getSizeOfEachArgOnStack();
228              sizeForThisCall = numExtra * (unsigned) argSize;
229            }
230          else
231            {
232              assert(0 && "UNTESTED CODE: Size per stack argument is not "
233                     "fixed on this architecture: use actual arg sizes to "
234                     "compute MaxOptionalArgsSize");
235              sizeForThisCall = 0;
236              for (unsigned i = 0; i < numOperands; ++i)
237                sizeForThisCall += target.getTargetData().getTypeSize(callInst->
238                                              getOperand(i)->getType());
239            }
240
241          if (maxSize < sizeForThisCall)
242            maxSize = sizeForThisCall;
243
244          if ((int)maxOptionalNumArgs < numExtra)
245            maxOptionalNumArgs = (unsigned) numExtra;
246        }
247
248  return maxSize;
249}
250
251// Align data larger than one L1 cache line on L1 cache line boundaries.
252// Align all smaller data on the next higher 2^x boundary (4, 8, ...),
253// but not higher than the alignment of the largest type we support
254// (currently a double word). -- see class TargetData).
255//
256// This function is similar to the corresponding function in EmitAssembly.cpp
257// but they are unrelated.  This one does not align at more than a
258// double-word boundary whereas that one might.
259//
260inline unsigned
261SizeToAlignment(unsigned size, const TargetMachine& target)
262{
263  unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
264  if (size > (unsigned) cacheLineSize / 2)
265    return cacheLineSize;
266  else
267    for (unsigned sz=1; /*no condition*/; sz *= 2)
268      if (sz >= size || sz >= target.getTargetData().getDoubleAlignment())
269        return sz;
270}
271
272
273void MachineFunctionInfo::CalculateArgSize() {
274  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(MF.getTarget(),
275						   MF.getFunction(),
276                                                   maxOptionalNumArgs);
277  staticStackSize = maxOptionalArgsSize
278    + MF.getTarget().getFrameInfo().getMinStackFrameSize();
279}
280
281int
282MachineFunctionInfo::computeOffsetforLocalVar(const Value* val,
283					      unsigned &getPaddedSize,
284					      unsigned  sizeToUse)
285{
286  if (sizeToUse == 0)
287    sizeToUse = MF.getTarget().findOptimalStorageSize(val->getType());
288  unsigned align = SizeToAlignment(sizeToUse, MF.getTarget());
289
290  bool growUp;
291  int firstOffset = MF.getTarget().getFrameInfo().getFirstAutomaticVarOffset(MF,
292									     growUp);
293  int offset = growUp? firstOffset + getAutomaticVarsSize()
294                     : firstOffset - (getAutomaticVarsSize() + sizeToUse);
295
296  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
297  getPaddedSize = sizeToUse + abs(aligned - offset);
298
299  return aligned;
300}
301
302
303int MachineFunctionInfo::allocateLocalVar(const Value* val,
304                                          unsigned sizeToUse) {
305  assert(! automaticVarsAreaFrozen &&
306         "Size of auto vars area has been used to compute an offset so "
307         "no more automatic vars should be allocated!");
308
309  // Check if we've allocated a stack slot for this value already
310  //
311  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
312  if (pair != offsets.end())
313    return pair->second;
314
315  unsigned getPaddedSize;
316  unsigned offset = computeOffsetforLocalVar(val, getPaddedSize, sizeToUse);
317  offsets[val] = offset;
318  incrementAutomaticVarsSize(getPaddedSize);
319  return offset;
320}
321
322int
323MachineFunctionInfo::allocateSpilledValue(const Type* type)
324{
325  assert(! spillsAreaFrozen &&
326         "Size of reg spills area has been used to compute an offset so "
327         "no more register spill slots should be allocated!");
328
329  unsigned size  = MF.getTarget().getTargetData().getTypeSize(type);
330  unsigned char align = MF.getTarget().getTargetData().getTypeAlignment(type);
331
332  bool growUp;
333  int firstOffset = MF.getTarget().getFrameInfo().getRegSpillAreaOffset(MF, growUp);
334
335  int offset = growUp? firstOffset + getRegSpillsSize()
336                     : firstOffset - (getRegSpillsSize() + size);
337
338  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
339  size += abs(aligned - offset); // include alignment padding in size
340
341  incrementRegSpillsSize(size);  // update size of reg. spills area
342
343  return aligned;
344}
345
346int
347MachineFunctionInfo::pushTempValue(unsigned size)
348{
349  unsigned align = SizeToAlignment(size, MF.getTarget());
350
351  bool growUp;
352  int firstOffset = MF.getTarget().getFrameInfo().getTmpAreaOffset(MF, growUp);
353
354  int offset = growUp? firstOffset + currentTmpValuesSize
355                     : firstOffset - (currentTmpValuesSize + size);
356
357  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp,
358							      align);
359  size += abs(aligned - offset); // include alignment padding in size
360
361  incrementTmpAreaSize(size);    // update "current" size of tmp area
362
363  return aligned;
364}
365
366void MachineFunctionInfo::popAllTempValues() {
367  resetTmpAreaSize();            // clear tmp area to reuse
368}
369
370