MachineFunction.cpp revision 4d149cdae1553426f49623fdae215d481d56d955 
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 <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
83Pass *createMachineCodeConstructionPass(TargetMachine &Target) {
84  return new ConstructMachineFunction(Target);
85}
86
87Pass *createMachineCodeDestructionPass() {
88  return new DestroyMachineFunction();
89}
90
91Pass *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(OS);
124
125  // Print Constant Pool
126  getConstantPool()->print(OS);
127
128  for (const_iterator BB = begin(); BB != end(); ++BB) {
129    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(std::ostream &OS) const {
192  for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
193    const StackObject &SO = Objects[i];
194    OS << "  <fi #" << (int)(i-NumFixedObjects) << "> is ";
195    if (SO.Size == 0)
196      OS << "variable sized";
197    else
198      OS << SO.Size << " byte" << (SO.Size != 1 ? "s" : " ");
199
200    if (i < NumFixedObjects)
201      OS << " fixed";
202    if (i < NumFixedObjects || SO.SPOffset != -1) {
203      OS << " at location [SP";
204      if (SO.SPOffset > 0)
205	OS << "+" << SO.SPOffset;
206      else if (SO.SPOffset < 0)
207	OS << SO.SPOffset;
208      OS << "]";
209    }
210    OS << "\n";
211  }
212
213  if (HasVarSizedObjects)
214    OS << "  Stack frame contains variable sized objects\n";
215}
216
217void MachineFrameInfo::dump() const { print(std::cerr); }
218
219
220//===----------------------------------------------------------------------===//
221//  MachineConstantPool implementation
222//===----------------------------------------------------------------------===//
223
224void MachineConstantPool::print(std::ostream &OS) const {
225  for (unsigned i = 0, e = Constants.size(); i != e; ++i)
226    OS << "  <cp #" << i << "> is" << *(Value*)Constants[i] << "\n";
227}
228
229void MachineConstantPool::dump() const { print(std::cerr); }
230
231//===----------------------------------------------------------------------===//
232//  MachineFunctionInfo implementation
233//===----------------------------------------------------------------------===//
234
235static unsigned
236ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
237                           unsigned &maxOptionalNumArgs)
238{
239  const TargetFrameInfo &frameInfo = target.getFrameInfo();
240
241  unsigned maxSize = 0;
242
243  for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
244    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
245      if (const CallInst *callInst = dyn_cast<CallInst>(&*I))
246        {
247          unsigned numOperands = callInst->getNumOperands() - 1;
248          int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
249          if (numExtra <= 0)
250            continue;
251
252          unsigned sizeForThisCall;
253          if (frameInfo.argsOnStackHaveFixedSize())
254            {
255              int argSize = frameInfo.getSizeOfEachArgOnStack();
256              sizeForThisCall = numExtra * (unsigned) argSize;
257            }
258          else
259            {
260              assert(0 && "UNTESTED CODE: Size per stack argument is not "
261                     "fixed on this architecture: use actual arg sizes to "
262                     "compute MaxOptionalArgsSize");
263              sizeForThisCall = 0;
264              for (unsigned i = 0; i < numOperands; ++i)
265                sizeForThisCall += target.getTargetData().getTypeSize(callInst->
266                                              getOperand(i)->getType());
267            }
268
269          if (maxSize < sizeForThisCall)
270            maxSize = sizeForThisCall;
271
272          if ((int)maxOptionalNumArgs < numExtra)
273            maxOptionalNumArgs = (unsigned) numExtra;
274        }
275
276  return maxSize;
277}
278
279// Align data larger than one L1 cache line on L1 cache line boundaries.
280// Align all smaller data on the next higher 2^x boundary (4, 8, ...),
281// but not higher than the alignment of the largest type we support
282// (currently a double word). -- see class TargetData).
283//
284// This function is similar to the corresponding function in EmitAssembly.cpp
285// but they are unrelated.  This one does not align at more than a
286// double-word boundary whereas that one might.
287//
288inline unsigned
289SizeToAlignment(unsigned size, const TargetMachine& target)
290{
291  unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
292  if (size > (unsigned) cacheLineSize / 2)
293    return cacheLineSize;
294  else
295    for (unsigned sz=1; /*no condition*/; sz *= 2)
296      if (sz >= size || sz >= target.getTargetData().getDoubleAlignment())
297        return sz;
298}
299
300
301void MachineFunctionInfo::CalculateArgSize() {
302  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(MF.getTarget(),
303						   MF.getFunction(),
304                                                   maxOptionalNumArgs);
305  staticStackSize = maxOptionalArgsSize
306    + MF.getTarget().getFrameInfo().getMinStackFrameSize();
307}
308
309int
310MachineFunctionInfo::computeOffsetforLocalVar(const Value* val,
311					      unsigned &getPaddedSize,
312					      unsigned  sizeToUse)
313{
314  if (sizeToUse == 0)
315    sizeToUse = MF.getTarget().findOptimalStorageSize(val->getType());
316  unsigned align = SizeToAlignment(sizeToUse, MF.getTarget());
317
318  bool growUp;
319  int firstOffset = MF.getTarget().getFrameInfo().getFirstAutomaticVarOffset(MF,
320									     growUp);
321  int offset = growUp? firstOffset + getAutomaticVarsSize()
322                     : firstOffset - (getAutomaticVarsSize() + sizeToUse);
323
324  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
325  getPaddedSize = sizeToUse + abs(aligned - offset);
326
327  return aligned;
328}
329
330int
331MachineFunctionInfo::allocateLocalVar(const Value* val,
332				      unsigned sizeToUse)
333{
334  assert(! automaticVarsAreaFrozen &&
335         "Size of auto vars area has been used to compute an offset so "
336         "no more automatic vars should be allocated!");
337
338  // Check if we've allocated a stack slot for this value already
339  //
340  int offset = getOffset(val);
341  if (offset == INVALID_FRAME_OFFSET)
342    {
343      unsigned getPaddedSize;
344      offset = computeOffsetforLocalVar(val, getPaddedSize, sizeToUse);
345      offsets[val] = offset;
346      incrementAutomaticVarsSize(getPaddedSize);
347    }
348  return offset;
349}
350
351int
352MachineFunctionInfo::allocateSpilledValue(const Type* type)
353{
354  assert(! spillsAreaFrozen &&
355         "Size of reg spills area has been used to compute an offset so "
356         "no more register spill slots should be allocated!");
357
358  unsigned size  = MF.getTarget().getTargetData().getTypeSize(type);
359  unsigned char align = MF.getTarget().getTargetData().getTypeAlignment(type);
360
361  bool growUp;
362  int firstOffset = MF.getTarget().getFrameInfo().getRegSpillAreaOffset(MF, growUp);
363
364  int offset = growUp? firstOffset + getRegSpillsSize()
365                     : firstOffset - (getRegSpillsSize() + size);
366
367  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp, align);
368  size += abs(aligned - offset); // include alignment padding in size
369
370  incrementRegSpillsSize(size);  // update size of reg. spills area
371
372  return aligned;
373}
374
375int
376MachineFunctionInfo::pushTempValue(unsigned size)
377{
378  unsigned align = SizeToAlignment(size, MF.getTarget());
379
380  bool growUp;
381  int firstOffset = MF.getTarget().getFrameInfo().getTmpAreaOffset(MF, growUp);
382
383  int offset = growUp? firstOffset + currentTmpValuesSize
384                     : firstOffset - (currentTmpValuesSize + size);
385
386  int aligned = MF.getTarget().getFrameInfo().adjustAlignment(offset, growUp,
387							      align);
388  size += abs(aligned - offset); // include alignment padding in size
389
390  incrementTmpAreaSize(size);    // update "current" size of tmp area
391
392  return aligned;
393}
394
395void MachineFunctionInfo::popAllTempValues() {
396  resetTmpAreaSize();            // clear tmp area to reuse
397}
398
399int
400MachineFunctionInfo::getOffset(const Value* val) const
401{
402  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
403  return (pair == offsets.end()) ? INVALID_FRAME_OFFSET : pair->second;
404}
405