MachineFunction.cpp revision 831fdcf0177a4eef66129cd6fb4138922c492bf0 
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/Target/TargetMachine.h"
14#include "llvm/Target/MachineFrameInfo.h"
15#include "llvm/Target/MachineCacheInfo.h"
16#include "llvm/Function.h"
17#include "llvm/iOther.h"
18#include "llvm/Pass.h"
19#include <limits.h>
20
21const int INVALID_FRAME_OFFSET = INT_MAX; // std::numeric_limits<int>::max();
22
23static AnnotationID MF_AID(
24                 AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
25
26
27//===---------------------------------------------------------------------===//
28// Code generation/destruction passes
29//===---------------------------------------------------------------------===//
30
31namespace {
32  class ConstructMachineFunction : public FunctionPass {
33    TargetMachine &Target;
34  public:
35    ConstructMachineFunction(TargetMachine &T) : Target(T) {}
36
37    const char *getPassName() const {
38      return "ConstructMachineFunction";
39    }
40
41    bool runOnFunction(Function &F) {
42      MachineFunction::construct(&F, Target).CalculateArgSize();
43      return false;
44    }
45  };
46
47  struct DestroyMachineFunction : public FunctionPass {
48    const char *getPassName() const { return "FreeMachineFunction"; }
49
50    static void freeMachineCode(Instruction &I) {
51      MachineCodeForInstruction::destroy(&I);
52    }
53
54    bool runOnFunction(Function &F) {
55      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
56        for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E; ++I)
57          MachineCodeForInstruction::get(I).dropAllReferences();
58
59      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
60        for_each(FI->begin(), FI->end(), freeMachineCode);
61
62      return false;
63    }
64  };
65
66  struct Printer : public FunctionPass {
67    const char *getPassName() const { return "MachineFunction Printer"; }
68
69    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
70      AU.setPreservesAll();
71    }
72
73    bool runOnFunction(Function &F) {
74      MachineFunction::get(&F).dump();
75      return false;
76    }
77  };
78}
79
80Pass *createMachineCodeConstructionPass(TargetMachine &Target) {
81  return new ConstructMachineFunction(Target);
82}
83
84Pass *createMachineCodeDestructionPass() {
85  return new DestroyMachineFunction();
86}
87
88Pass *createMachineFunctionPrinterPass() {
89  return new Printer();
90}
91
92
93//===---------------------------------------------------------------------===//
94// MachineFunction implementation
95//===---------------------------------------------------------------------===//
96
97MachineFunction::MachineFunction(const Function *F,
98                                 const TargetMachine& target)
99  : Annotation(MF_AID), Fn(F), Target(target) {
100  SSARegMapping = new SSARegMap();
101
102  // FIXME: move state into another class
103  staticStackSize = automaticVarsSize = regSpillsSize = 0;
104  maxOptionalArgsSize = maxOptionalNumArgs = currentTmpValuesSize = 0;
105  maxTmpValuesSize = 0;
106  compiledAsLeaf = spillsAreaFrozen = automaticVarsAreaFrozen = false;
107}
108
109MachineFunction::~MachineFunction() {
110  delete SSARegMapping;
111}
112
113void MachineFunction::dump() const { print(std::cerr); }
114
115void MachineFunction::print(std::ostream &OS) const {
116  OS << "\n" << *(Value*)Fn->getReturnType() << " \"" << Fn->getName()<< "\"\n";
117
118  for (const_iterator BB = begin(); BB != end(); ++BB) {
119    BasicBlock *LBB = BB->getBasicBlock();
120    OS << "\n" << LBB->getName() << " (" << (const void*)LBB << "):\n";
121    for (MachineBasicBlock::const_iterator I = BB->begin(); I != BB->end();++I){
122      OS << "\t";
123      (*I)->print(OS, Target);
124    }
125  }
126  OS << "\nEnd function \"" << Fn->getName() << "\"\n\n";
127}
128
129
130// The next two methods are used to construct and to retrieve
131// the MachineCodeForFunction object for the given function.
132// construct() -- Allocates and initializes for a given function and target
133// get()       -- Returns a handle to the object.
134//                This should not be called before "construct()"
135//                for a given Function.
136//
137MachineFunction&
138MachineFunction::construct(const Function *Fn, const TargetMachine &Tar)
139{
140  assert(Fn->getAnnotation(MF_AID) == 0 &&
141         "Object already exists for this function!");
142  MachineFunction* mcInfo = new MachineFunction(Fn, Tar);
143  Fn->addAnnotation(mcInfo);
144  return *mcInfo;
145}
146
147void
148MachineFunction::destruct(const Function *Fn)
149{
150  bool Deleted = Fn->deleteAnnotation(MF_AID);
151  assert(Deleted && "Machine code did not exist for function!");
152}
153
154MachineFunction& MachineFunction::get(const Function *F)
155{
156  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MF_AID);
157  assert(mc && "Call construct() method first to allocate the object");
158  return *mc;
159}
160
161void MachineFunction::clearSSARegMap() {
162  delete SSARegMapping;
163  SSARegMapping = 0;
164}
165
166
167static unsigned
168ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
169                           unsigned &maxOptionalNumArgs)
170{
171  const MachineFrameInfo& frameInfo = target.getFrameInfo();
172
173  unsigned maxSize = 0;
174
175  for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
176    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
177      if (const CallInst *callInst = dyn_cast<CallInst>(&*I))
178        {
179          unsigned numOperands = callInst->getNumOperands() - 1;
180          int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
181          if (numExtra <= 0)
182            continue;
183
184          unsigned int sizeForThisCall;
185          if (frameInfo.argsOnStackHaveFixedSize())
186            {
187              int argSize = frameInfo.getSizeOfEachArgOnStack();
188              sizeForThisCall = numExtra * (unsigned) argSize;
189            }
190          else
191            {
192              assert(0 && "UNTESTED CODE: Size per stack argument is not "
193                     "fixed on this architecture: use actual arg sizes to "
194                     "compute MaxOptionalArgsSize");
195              sizeForThisCall = 0;
196              for (unsigned i = 0; i < numOperands; ++i)
197                sizeForThisCall += target.DataLayout.getTypeSize(callInst->
198                                              getOperand(i)->getType());
199            }
200
201          if (maxSize < sizeForThisCall)
202            maxSize = sizeForThisCall;
203
204          if ((int)maxOptionalNumArgs < numExtra)
205            maxOptionalNumArgs = (unsigned) numExtra;
206        }
207
208  return maxSize;
209}
210
211// Align data larger than one L1 cache line on L1 cache line boundaries.
212// Align all smaller data on the next higher 2^x boundary (4, 8, ...),
213// but not higher than the alignment of the largest type we support
214// (currently a double word). -- see class TargetData).
215//
216// This function is similar to the corresponding function in EmitAssembly.cpp
217// but they are unrelated.  This one does not align at more than a
218// double-word boundary whereas that one might.
219//
220inline unsigned int
221SizeToAlignment(unsigned int size, const TargetMachine& target)
222{
223  unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
224  if (size > (unsigned) cacheLineSize / 2)
225    return cacheLineSize;
226  else
227    for (unsigned sz=1; /*no condition*/; sz *= 2)
228      if (sz >= size || sz >= target.DataLayout.getDoubleAlignment())
229        return sz;
230}
231
232
233void MachineFunction::CalculateArgSize() {
234  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(Target, Fn,
235                                                   maxOptionalNumArgs);
236  staticStackSize = maxOptionalArgsSize
237    + Target.getFrameInfo().getMinStackFrameSize();
238}
239
240int
241MachineFunction::computeOffsetforLocalVar(const TargetMachine& target,
242                                               const Value* val,
243                                               unsigned int& getPaddedSize,
244                                               unsigned int  sizeToUse)
245{
246  if (sizeToUse == 0)
247    sizeToUse = target.findOptimalStorageSize(val->getType());
248  unsigned int align = SizeToAlignment(sizeToUse, target);
249
250  bool growUp;
251  int firstOffset = target.getFrameInfo().getFirstAutomaticVarOffset(*this,
252                                                                     growUp);
253  int offset = growUp? firstOffset + getAutomaticVarsSize()
254                     : firstOffset - (getAutomaticVarsSize() + sizeToUse);
255
256  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
257  getPaddedSize = sizeToUse + abs(aligned - offset);
258
259  return aligned;
260}
261
262int
263MachineFunction::allocateLocalVar(const TargetMachine& target,
264                                       const Value* val,
265                                       unsigned int sizeToUse)
266{
267  assert(! automaticVarsAreaFrozen &&
268         "Size of auto vars area has been used to compute an offset so "
269         "no more automatic vars should be allocated!");
270
271  // Check if we've allocated a stack slot for this value already
272  //
273  int offset = getOffset(val);
274  if (offset == INVALID_FRAME_OFFSET)
275    {
276      unsigned int getPaddedSize;
277      offset = computeOffsetforLocalVar(target, val, getPaddedSize, sizeToUse);
278      offsets[val] = offset;
279      incrementAutomaticVarsSize(getPaddedSize);
280    }
281  return offset;
282}
283
284int
285MachineFunction::allocateSpilledValue(const TargetMachine& target,
286                                           const Type* type)
287{
288  assert(! spillsAreaFrozen &&
289         "Size of reg spills area has been used to compute an offset so "
290         "no more register spill slots should be allocated!");
291
292  unsigned int size  = target.DataLayout.getTypeSize(type);
293  unsigned char align = target.DataLayout.getTypeAlignment(type);
294
295  bool growUp;
296  int firstOffset = target.getFrameInfo().getRegSpillAreaOffset(*this, growUp);
297
298  int offset = growUp? firstOffset + getRegSpillsSize()
299                     : firstOffset - (getRegSpillsSize() + size);
300
301  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
302  size += abs(aligned - offset); // include alignment padding in size
303
304  incrementRegSpillsSize(size);  // update size of reg. spills area
305
306  return aligned;
307}
308
309int
310MachineFunction::pushTempValue(const TargetMachine& target,
311                                    unsigned int size)
312{
313  unsigned int align = SizeToAlignment(size, target);
314
315  bool growUp;
316  int firstOffset = target.getFrameInfo().getTmpAreaOffset(*this, growUp);
317
318  int offset = growUp? firstOffset + currentTmpValuesSize
319                     : firstOffset - (currentTmpValuesSize + size);
320
321  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
322  size += abs(aligned - offset); // include alignment padding in size
323
324  incrementTmpAreaSize(size);    // update "current" size of tmp area
325
326  return aligned;
327}
328
329void
330MachineFunction::popAllTempValues(const TargetMachine& target)
331{
332  resetTmpAreaSize();            // clear tmp area to reuse
333}
334
335int
336MachineFunction::getOffset(const Value* val) const
337{
338  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
339  return (pair == offsets.end()) ? INVALID_FRAME_OFFSET : pair->second;
340}
341