MachineFunction.cpp revision 19df3876e6dce016ec4c5ab28320a246ab285001 
1//===-- MachineFunction.cpp -----------------------------------------------===//
2//
3// Collect native machine code information for a function.  This allows
4// target-specific information about the generated code to be stored with each
5// function.
6//
7//===----------------------------------------------------------------------===//
8
9#include "llvm/CodeGen/MachineFunction.h"
10#include "llvm/CodeGen/MachineInstr.h"
11#include "llvm/CodeGen/MachineCodeForInstruction.h"
12#include "llvm/CodeGen/SSARegMap.h"
13#include "llvm/CodeGen/MachineFunctionInfo.h"
14#include "llvm/CodeGen/MachineFrameInfo.h"
15#include "llvm/CodeGen/MachineConstantPool.h"
16#include "llvm/Target/TargetMachine.h"
17#include "llvm/Target/TargetFrameInfo.h"
18#include "llvm/Target/TargetCacheInfo.h"
19#include "llvm/Function.h"
20#include "llvm/iOther.h"
21#include "llvm/Pass.h"
22#include "Config/limits.h"
23
24const int INVALID_FRAME_OFFSET = INT_MAX; // std::numeric_limits<int>::max();
25
26static AnnotationID MF_AID(
27                 AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
28
29
30//===---------------------------------------------------------------------===//
31// Code generation/destruction passes
32//===---------------------------------------------------------------------===//
33
34namespace {
35  class ConstructMachineFunction : public FunctionPass {
36    TargetMachine &Target;
37  public:
38    ConstructMachineFunction(TargetMachine &T) : Target(T) {}
39
40    const char *getPassName() const {
41      return "ConstructMachineFunction";
42    }
43
44    bool runOnFunction(Function &F) {
45      MachineFunction::construct(&F, Target).getInfo()->CalculateArgSize();
46      return false;
47    }
48  };
49
50  struct DestroyMachineFunction : public FunctionPass {
51    const char *getPassName() const { return "FreeMachineFunction"; }
52
53    static void freeMachineCode(Instruction &I) {
54      MachineCodeForInstruction::destroy(&I);
55    }
56
57    bool runOnFunction(Function &F) {
58      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
59        for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E; ++I)
60          MachineCodeForInstruction::get(I).dropAllReferences();
61
62      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
63        for_each(FI->begin(), FI->end(), freeMachineCode);
64
65      return false;
66    }
67  };
68
69  struct Printer : public FunctionPass {
70    const char *getPassName() const { return "MachineFunction Printer"; }
71
72    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
73      AU.setPreservesAll();
74    }
75
76    bool runOnFunction(Function &F) {
77      MachineFunction::get(&F).dump();
78      return false;
79    }
80  };
81}
82
83FunctionPass *createMachineCodeConstructionPass(TargetMachine &Target) {
84  return new ConstructMachineFunction(Target);
85}
86
87FunctionPass *createMachineCodeDestructionPass() {
88  return new DestroyMachineFunction();
89}
90
91FunctionPass *createMachineFunctionPrinterPass() {
92  return new Printer();
93}
94
95
96//===---------------------------------------------------------------------===//
97// MachineFunction implementation
98//===---------------------------------------------------------------------===//
99
100MachineFunction::MachineFunction(const Function *F,
101                                 const TargetMachine &TM)
102  : Annotation(MF_AID), Fn(F), Target(TM) {
103  SSARegMapping = new SSARegMap();
104  MFInfo = new MachineFunctionInfo(*this);
105  FrameInfo = new MachineFrameInfo();
106  ConstantPool = new MachineConstantPool();
107}
108
109MachineFunction::~MachineFunction() {
110  delete SSARegMapping;
111  delete MFInfo;
112  delete FrameInfo;
113  delete ConstantPool;
114}
115
116void MachineFunction::dump() const { print(std::cerr); }
117
118void MachineFunction::print(std::ostream &OS) const {
119  OS << "\n" << *(Value*)Fn->getFunctionType() << " \"" << Fn->getName()
120     << "\"\n";
121
122  // Print Frame Information
123  getFrameInfo()->print(*this, OS);
124
125  // Print Constant Pool
126  getConstantPool()->print(OS);
127
128  for (const_iterator BB = begin(); BB != end(); ++BB) {
129    const BasicBlock *LBB = BB->getBasicBlock();
130    OS << "\n" << LBB->getName() << " (" << (const void*)LBB << "):\n";
131    for (MachineBasicBlock::const_iterator I = BB->begin(); I != BB->end();++I){
132      OS << "\t";
133      (*I)->print(OS, Target);
134    }
135  }
136  OS << "\nEnd function \"" << Fn->getName() << "\"\n\n";
137}
138
139
140// The next two methods are used to construct and to retrieve
141// the MachineCodeForFunction object for the given function.
142// construct() -- Allocates and initializes for a given function and target
143// get()       -- Returns a handle to the object.
144//                This should not be called before "construct()"
145//                for a given Function.
146//
147MachineFunction&
148MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
149{
150  assert(Fn->getAnnotation(MF_AID) == 0 &&
151         "Object already exists for this function!");
152  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
153  Fn->addAnnotation(mcInfo);
154  return *mcInfo;
155}
156
157void
158MachineFunction::destruct(const Function *Fn)
159{
160  bool Deleted = Fn->deleteAnnotation(MF_AID);
161  assert(Deleted && "Machine code did not exist for function!");
162}
163
164MachineFunction& MachineFunction::get(const Function *F)
165{
166  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
167  assert(mc && "Call construct() method first to allocate the object");
168  return *mc;
169}
170
171void MachineFunction::clearSSARegMap() {
172  delete SSARegMapping;
173  SSARegMapping = 0;
174}
175
176//===----------------------------------------------------------------------===//
177//  MachineFrameInfo implementation
178//===----------------------------------------------------------------------===//
179
180/// CreateStackObject - Create a stack object for a value of the specified type.
181///
182int MachineFrameInfo::CreateStackObject(const Type *Ty, const TargetData &TD) {
183  return CreateStackObject(TD.getTypeSize(Ty), TD.getTypeAlignment(Ty));
184}
185
186int MachineFrameInfo::CreateStackObject(const TargetRegisterClass *RC) {
187  return CreateStackObject(RC->getSize(), RC->getAlignment());
188}
189
190
191void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
192  int ValOffset = MF.getTarget().getFrameInfo().getOffsetOfLocalArea();
193
194  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
195    const StackObject &SO = Objects[i];
196    OS << "  <fi #" << (int)(i-NumFixedObjects) << "> is ";
197    if (SO.Size == 0)
198      OS << "variable sized";
199    else
200      OS << SO.Size << " byte" << (SO.Size != 1 ? "s" : " ");
201
202    if (i < NumFixedObjects)
203      OS << " fixed";
204    if (i < NumFixedObjects || SO.SPOffset != -1) {
205      int Off = SO.SPOffset + ValOffset;
206      OS << " at location [SP";
207      if (Off > 0)
208	OS << "+" << Off;
209      else if (Off < 0)
210	OS << Off;
211      OS << "]";
212    }
213    OS << "\n";
214  }
215
216  if (HasVarSizedObjects)
217    OS << "  Stack frame contains variable sized objects\n";
218}
219
220void MachineFrameInfo::dump(const MachineFunction &MF) const {
221  print(MF, std::cerr);
222}
223
224
225//===----------------------------------------------------------------------===//
226//  MachineConstantPool implementation
227//===----------------------------------------------------------------------===//
228
229void MachineConstantPool::print(std::ostream &OS) const {
230  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
231    OS << "  <cp #" << i << "> is" << *(Value*)Constants[i] << "\n";
232}
233
234void MachineConstantPool::dump() const { print(std::cerr); }
235
236//===----------------------------------------------------------------------===//
237//  MachineFunctionInfo implementation
238//===----------------------------------------------------------------------===//
239
240static unsigned
241ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
242                           unsigned &maxOptionalNumArgs)
243{
244  const TargetFrameInfo &frameInfo = target.getFrameInfo();
245
246  unsigned maxSize = 0;
247
248  for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
249    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
250      if (const CallInst *callInst = dyn_cast<CallInst>(I))
251        {
252          unsigned numOperands = callInst->getNumOperands() - 1;
253          int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
254          if (numExtra <= 0)
255            continue;
256
257          unsigned sizeForThisCall;
258          if (frameInfo.argsOnStackHaveFixedSize())
259            {
260              int argSize = frameInfo.getSizeOfEachArgOnStack();
261              sizeForThisCall = numExtra * (unsigned) argSize;
262            }
263          else
264            {
265              assert(0 && "UNTESTED CODE: Size per stack argument is not "
266                     "fixed on this architecture: use actual arg sizes to "
267                     "compute MaxOptionalArgsSize");
268              sizeForThisCall = 0;
269              for (unsigned i = 0; i < numOperands; ++i)
270                sizeForThisCall += target.getTargetData().getTypeSize(callInst->
271                                              getOperand(i)->getType());
272            }
273
274          if (maxSize < sizeForThisCall)
275            maxSize = sizeForThisCall;
276
277          if ((int)maxOptionalNumArgs < numExtra)
278            maxOptionalNumArgs = (unsigned) numExtra;
279        }
280
281  return maxSize;
282}
283
284// Align data larger than one L1 cache line on L1 cache line boundaries.
285// Align all smaller data on the next higher 2^x boundary (4, 8, ...),
286// but not higher than the alignment of the largest type we support
287// (currently a double word). -- see class TargetData).
288//
289// This function is similar to the corresponding function in EmitAssembly.cpp
290// but they are unrelated.  This one does not align at more than a
291// double-word boundary whereas that one might.
292//
293inline unsigned
294SizeToAlignment(unsigned size, const TargetMachine& target)
295{
296  unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
297  if (size > (unsigned) cacheLineSize / 2)
298    return cacheLineSize;
299  else
300    for (unsigned sz=1; /*no condition*/; sz *= 2)
301      if (sz >= size || sz >= target.getTargetData().getDoubleAlignment())
302        return sz;
303}
304
305
306void MachineFunctionInfo::CalculateArgSize() {
307  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(MF.getTarget(),
308						   MF.getFunction(),
309                                                   maxOptionalNumArgs);
310  staticStackSize = maxOptionalArgsSize
311    + MF.getTarget().getFrameInfo().getMinStackFrameSize();
312}
313
314int
315MachineFunctionInfo::computeOffsetforLocalVar(const Value* val,
316					      unsigned &getPaddedSize,
317					      unsigned  sizeToUse)
318{
319  if (sizeToUse == 0)
320    sizeToUse = MF.getTarget().findOptimalStorageSize(val->getType());
321  unsigned align = SizeToAlignment(sizeToUse, MF.getTarget());
322
323  bool growUp;
324  int firstOffset = MF.getTarget().getFrameInfo().getFirstAutomaticVarOffset(MF,
325									     growUp);
326  int offset = growUp? firstOffset + getAutomaticVarsSize()
327                     : firstOffset - (getAutomaticVarsSize() + sizeToUse);
328
329  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
330  getPaddedSize = sizeToUse + abs(aligned - offset);
331
332  return aligned;
333}
334
335int
336MachineFunctionInfo::allocateLocalVar(const Value* val,
337				      unsigned sizeToUse)
338{
339  assert(! automaticVarsAreaFrozen &&
340         "Size of auto vars area has been used to compute an offset so "
341         "no more automatic vars should be allocated!");
342
343  // Check if we've allocated a stack slot for this value already
344  //
345  int offset = getOffset(val);
346  if (offset == INVALID_FRAME_OFFSET)
347    {
348      unsigned getPaddedSize;
349      offset = computeOffsetforLocalVar(val, getPaddedSize, sizeToUse);
350      offsets[val] = offset;
351      incrementAutomaticVarsSize(getPaddedSize);
352    }
353  return offset;
354}
355
356int
357MachineFunctionInfo::allocateSpilledValue(const Type* type)
358{
359  assert(! spillsAreaFrozen &&
360         "Size of reg spills area has been used to compute an offset so "
361         "no more register spill slots should be allocated!");
362
363  unsigned size  = MF.getTarget().getTargetData().getTypeSize(type);
364  unsigned char align = MF.getTarget().getTargetData().getTypeAlignment(type);
365
366  bool growUp;
367  int firstOffset = MF.getTarget().getFrameInfo().getRegSpillAreaOffset(MF, growUp);
368
369  int offset = growUp? firstOffset + getRegSpillsSize()
370                     : firstOffset - (getRegSpillsSize() + size);
371
372  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
373  size += abs(aligned - offset); // include alignment padding in size
374
375  incrementRegSpillsSize(size);  // update size of reg. spills area
376
377  return aligned;
378}
379
380int
381MachineFunctionInfo::pushTempValue(unsigned size)
382{
383  unsigned align = SizeToAlignment(size, MF.getTarget());
384
385  bool growUp;
386  int firstOffset = MF.getTarget().getFrameInfo().getTmpAreaOffset(MF, growUp);
387
388  int offset = growUp? firstOffset + currentTmpValuesSize
389                     : firstOffset - (currentTmpValuesSize + size);
390
391  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp,
392							      align);
393  size += abs(aligned - offset); // include alignment padding in size
394
395  incrementTmpAreaSize(size);    // update "current" size of tmp area
396
397  return aligned;
398}
399
400void MachineFunctionInfo::popAllTempValues() {
401  resetTmpAreaSize();            // clear tmp area to reuse
402}
403
404int
405MachineFunctionInfo::getOffset(const Value* val) const
406{
407  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
408  return (pair == offsets.end()) ? INVALID_FRAME_OFFSET : pair->second;
409}
410