MachineFunction.cpp revision eb24db9727a7babe863d5afe70c7bda3a460da18 
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/Target/TargetMachine.h"
16#include "llvm/Target/TargetFrameInfo.h"
17#include "llvm/Target/MachineCacheInfo.h"
18#include "llvm/Function.h"
19#include "llvm/iOther.h"
20#include "llvm/Pass.h"
21#include <limits.h>
22
23const int INVALID_FRAME_OFFSET = INT_MAX; // std::numeric_limits<int>::max();
24
25static AnnotationID MF_AID(
26                 AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
27
28
29//===---------------------------------------------------------------------===//
30// Code generation/destruction passes
31//===---------------------------------------------------------------------===//
32
33namespace {
34  class ConstructMachineFunction : public FunctionPass {
35    TargetMachine &Target;
36  public:
37    ConstructMachineFunction(TargetMachine &T) : Target(T) {}
38
39    const char *getPassName() const {
40      return "ConstructMachineFunction";
41    }
42
43    bool runOnFunction(Function &F) {
44      MachineFunction::construct(&F, Target).getInfo()->CalculateArgSize();
45      return false;
46    }
47  };
48
49  struct DestroyMachineFunction : public FunctionPass {
50    const char *getPassName() const { return "FreeMachineFunction"; }
51
52    static void freeMachineCode(Instruction &I) {
53      MachineCodeForInstruction::destroy(&I);
54    }
55
56    bool runOnFunction(Function &F) {
57      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
58        for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E; ++I)
59          MachineCodeForInstruction::get(I).dropAllReferences();
60
61      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
62        for_each(FI->begin(), FI->end(), freeMachineCode);
63
64      return false;
65    }
66  };
67
68  struct Printer : public FunctionPass {
69    const char *getPassName() const { return "MachineFunction Printer"; }
70
71    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
72      AU.setPreservesAll();
73    }
74
75    bool runOnFunction(Function &F) {
76      MachineFunction::get(&F).dump();
77      return false;
78    }
79  };
80}
81
82Pass *createMachineCodeConstructionPass(TargetMachine &Target) {
83  return new ConstructMachineFunction(Target);
84}
85
86Pass *createMachineCodeDestructionPass() {
87  return new DestroyMachineFunction();
88}
89
90Pass *createMachineFunctionPrinterPass() {
91  return new Printer();
92}
93
94
95//===---------------------------------------------------------------------===//
96// MachineFunction implementation
97//===---------------------------------------------------------------------===//
98
99MachineFunction::MachineFunction(const Function *F,
100                                 const TargetMachine &TM)
101  : Annotation(MF_AID), Fn(F), Target(TM) {
102  SSARegMapping = new SSARegMap();
103  MFInfo = new MachineFunctionInfo(*this);
104  FrameInfo = new MachineFrameInfo();
105}
106
107MachineFunction::~MachineFunction() {
108  delete SSARegMapping;
109  delete MFInfo;
110  delete FrameInfo;
111}
112
113void MachineFunction::dump() const { print(std::cerr); }
114
115void MachineFunction::print(std::ostream &OS) const {
116  OS << "\n" << *(Value*)Fn->getFunctionType() << " \"" << Fn->getName()
117     << "\"\n";
118
119  // Print Frame Information
120  getFrameInfo()->print(OS);
121
122  for (const_iterator BB = begin(); BB != end(); ++BB) {
123    BasicBlock *LBB = BB->getBasicBlock();
124    OS << "\n" << LBB->getName() << " (" << (const void*)LBB << "):\n";
125    for (MachineBasicBlock::const_iterator I = BB->begin(); I != BB->end();++I){
126      OS << "\t";
127      (*I)->print(OS, Target);
128    }
129  }
130  OS << "\nEnd function \"" << Fn->getName() << "\"\n\n";
131}
132
133
134// The next two methods are used to construct and to retrieve
135// the MachineCodeForFunction object for the given function.
136// construct() -- Allocates and initializes for a given function and target
137// get()       -- Returns a handle to the object.
138//                This should not be called before "construct()"
139//                for a given Function.
140//
141MachineFunction&
142MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
143{
144  assert(Fn->getAnnotation(MF_AID) == 0 &&
145         "Object already exists for this function!");
146  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
147  Fn->addAnnotation(mcInfo);
148  return *mcInfo;
149}
150
151void
152MachineFunction::destruct(const Function *Fn)
153{
154  bool Deleted = Fn->deleteAnnotation(MF_AID);
155  assert(Deleted && "Machine code did not exist for function!");
156}
157
158MachineFunction& MachineFunction::get(const Function *F)
159{
160  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
161  assert(mc && "Call construct() method first to allocate the object");
162  return *mc;
163}
164
165void MachineFunction::clearSSARegMap() {
166  delete SSARegMapping;
167  SSARegMapping = 0;
168}
169
170//===----------------------------------------------------------------------===//
171//  MachineFrameInfo implementation
172//===----------------------------------------------------------------------===//
173
174void MachineFrameInfo::print(std::ostream &OS) const {
175  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
176    const StackObject &SO = Objects[i];
177    OS << "  <fi# " << (int)(i-NumFixedObjects) << "> is ";
178    if (SO.Size == 0)
179      OS << "variable sized";
180    else
181      OS << SO.Size << " byte" << (SO.Size != 1 ? "s" : " ");
182
183    if (i < NumFixedObjects)
184      OS << " fixed";
185    if (i < NumFixedObjects || SO.SPOffset != -1) {
186      OS << " at location [SP";
187      if (SO.SPOffset > 0)
188	OS << "+" << SO.SPOffset;
189      else if (SO.SPOffset < 0)
190	OS << SO.SPOffset;
191      OS << "]";
192    }
193    OS << "\n";
194  }
195
196  if (HasVarSizedObjects)
197    OS << "  Stack frame contains variable sized objects\n";
198}
199
200void MachineFrameInfo::dump() const { print(std::cerr); }
201
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
302int
303MachineFunctionInfo::allocateLocalVar(const Value* val,
304				      unsigned sizeToUse)
305{
306  assert(! automaticVarsAreaFrozen &&
307         "Size of auto vars area has been used to compute an offset so "
308         "no more automatic vars should be allocated!");
309
310  // Check if we've allocated a stack slot for this value already
311  //
312  int offset = getOffset(val);
313  if (offset == INVALID_FRAME_OFFSET)
314    {
315      unsigned getPaddedSize;
316      offset = computeOffsetforLocalVar(val, getPaddedSize, sizeToUse);
317      offsets[val] = offset;
318      incrementAutomaticVarsSize(getPaddedSize);
319    }
320  return offset;
321}
322
323int
324MachineFunctionInfo::allocateSpilledValue(const Type* type)
325{
326  assert(! spillsAreaFrozen &&
327         "Size of reg spills area has been used to compute an offset so "
328         "no more register spill slots should be allocated!");
329
330  unsigned size  = MF.getTarget().getTargetData().getTypeSize(type);
331  unsigned char align = MF.getTarget().getTargetData().getTypeAlignment(type);
332
333  bool growUp;
334  int firstOffset = MF.getTarget().getFrameInfo().getRegSpillAreaOffset(MF, growUp);
335
336  int offset = growUp? firstOffset + getRegSpillsSize()
337                     : firstOffset - (getRegSpillsSize() + size);
338
339  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
340  size += abs(aligned - offset); // include alignment padding in size
341
342  incrementRegSpillsSize(size);  // update size of reg. spills area
343
344  return aligned;
345}
346
347int
348MachineFunctionInfo::pushTempValue(unsigned size)
349{
350  unsigned align = SizeToAlignment(size, MF.getTarget());
351
352  bool growUp;
353  int firstOffset = MF.getTarget().getFrameInfo().getTmpAreaOffset(MF, growUp);
354
355  int offset = growUp? firstOffset + currentTmpValuesSize
356                     : firstOffset - (currentTmpValuesSize + size);
357
358  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp,
359							      align);
360  size += abs(aligned - offset); // include alignment padding in size
361
362  incrementTmpAreaSize(size);    // update "current" size of tmp area
363
364  return aligned;
365}
366
367void MachineFunctionInfo::popAllTempValues() {
368  resetTmpAreaSize();            // clear tmp area to reuse
369}
370
371int
372MachineFunctionInfo::getOffset(const Value* val) const
373{
374  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
375  return (pair == offsets.end()) ? INVALID_FRAME_OFFSET : pair->second;
376}
377