MachineFunction.cpp revision d0aa0cdbc6fee00f2b2019633a9b9d00d301ac68 
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/MachineInstr.h"  // For debug output
10#include "llvm/CodeGen/MachineFunction.h"
11#include "llvm/CodeGen/MachineCodeForInstruction.h"
12#include "llvm/Target/TargetMachine.h"
13#include "llvm/Target/MachineFrameInfo.h"
14#include "llvm/Target/MachineCacheInfo.h"
15#include "llvm/Function.h"
16#include "llvm/iOther.h"
17#include "llvm/Pass.h"
18#include <limits.h>
19
20const int INVALID_FRAME_OFFSET = INT_MAX; // std::numeric_limits<int>::max();
21
22static AnnotationID MCFM_AID(
23                 AnnotationManager::getID("CodeGen::MachineCodeForFunction"));
24
25
26//===---------------------------------------------------------------------===//
27// Code generation/destruction passes
28//===---------------------------------------------------------------------===//
29
30namespace {
31  class ConstructMachineFunction : public FunctionPass {
32    TargetMachine &Target;
33  public:
34    ConstructMachineFunction(TargetMachine &T) : Target(T) {}
35
36    const char *getPassName() const {
37      return "ConstructMachineFunction";
38    }
39
40    bool runOnFunction(Function &F) {
41      MachineFunction::construct(&F, Target);
42      return false;
43    }
44  };
45
46  struct DestroyMachineFunction : public FunctionPass {
47    const char *getPassName() const { return "FreeMachineFunction"; }
48
49    static void freeMachineCode(Instruction &I) {
50      MachineCodeForInstruction::destroy(&I);
51    }
52
53    bool runOnFunction(Function &F) {
54      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
55        for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E; ++I)
56          MachineCodeForInstruction::get(I).dropAllReferences();
57
58      for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
59        for_each(FI->begin(), FI->end(), freeMachineCode);
60
61      return false;
62    }
63  };
64}
65
66Pass *createMachineCodeConstructionPass(TargetMachine &Target) {
67  return new ConstructMachineFunction(Target);
68}
69
70Pass *createMachineCodeDestructionPass() {
71  return new DestroyMachineFunction();
72}
73
74
75// get - This deprecated static method returns the MachineBasicBlock object
76// for the specified BasicBlock.
77//
78MachineBasicBlock& MachineBasicBlock::get(const BasicBlock *BB) {
79  const Function *F = BB->getParent();
80  MachineFunction &MF = MachineFunction::get(F);
81
82  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
83    if (I->getBasicBlock() == BB)
84      return *I;
85  assert(0 && "MachineBasicBlock object not found for specified block!");
86  return get(BB);
87}
88
89
90//===---------------------------------------------------------------------===//
91// MachineFunction implementation
92//===---------------------------------------------------------------------===//
93
94// The next two methods are used to construct and to retrieve
95// the MachineCodeForFunction object for the given function.
96// construct() -- Allocates and initializes for a given function and target
97// get()       -- Returns a handle to the object.
98//                This should not be called before "construct()"
99//                for a given Function.
100//
101MachineFunction&
102MachineFunction::construct(const Function *M, const TargetMachine &Tar)
103{
104  assert(M->getAnnotation(MCFM_AID) == 0 &&
105         "Object already exists for this function!");
106  MachineFunction* mcInfo = new MachineFunction(M, Tar);
107  M->addAnnotation(mcInfo);
108  return *mcInfo;
109}
110
111void
112MachineFunction::destruct(const Function *M)
113{
114  bool Deleted = M->deleteAnnotation(MCFM_AID);
115  assert(Deleted && "Machine code did not exist for function!");
116}
117
118MachineFunction&
119MachineFunction::get(const Function *F)
120{
121  MachineFunction *mc = (MachineFunction*)F->getAnnotation(MCFM_AID);
122  assert(mc && "Call construct() method first to allocate the object");
123  return *mc;
124}
125
126static unsigned
127ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
128                           unsigned &maxOptionalNumArgs)
129{
130  const MachineFrameInfo& frameInfo = target.getFrameInfo();
131
132  unsigned maxSize = 0;
133
134  for (Function::const_iterator BB = F->begin(), BBE = F->end(); BB !=BBE; ++BB)
135    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
136      if (const CallInst *callInst = dyn_cast<CallInst>(&*I))
137        {
138          unsigned numOperands = callInst->getNumOperands() - 1;
139          int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
140          if (numExtra <= 0)
141            continue;
142
143          unsigned int sizeForThisCall;
144          if (frameInfo.argsOnStackHaveFixedSize())
145            {
146              int argSize = frameInfo.getSizeOfEachArgOnStack();
147              sizeForThisCall = numExtra * (unsigned) argSize;
148            }
149          else
150            {
151              assert(0 && "UNTESTED CODE: Size per stack argument is not "
152                     "fixed on this architecture: use actual arg sizes to "
153                     "compute MaxOptionalArgsSize");
154              sizeForThisCall = 0;
155              for (unsigned i = 0; i < numOperands; ++i)
156                sizeForThisCall += target.DataLayout.getTypeSize(callInst->
157                                              getOperand(i)->getType());
158            }
159
160          if (maxSize < sizeForThisCall)
161            maxSize = sizeForThisCall;
162
163          if ((int)maxOptionalNumArgs < numExtra)
164            maxOptionalNumArgs = (unsigned) numExtra;
165        }
166
167  return maxSize;
168}
169
170// Align data larger than one L1 cache line on L1 cache line boundaries.
171// Align all smaller data on the next higher 2^x boundary (4, 8, ...),
172// but not higher than the alignment of the largest type we support
173// (currently a double word). -- see class TargetData).
174//
175// This function is similar to the corresponding function in EmitAssembly.cpp
176// but they are unrelated.  This one does not align at more than a
177// double-word boundary whereas that one might.
178//
179inline unsigned int
180SizeToAlignment(unsigned int size, const TargetMachine& target)
181{
182  unsigned short cacheLineSize = target.getCacheInfo().getCacheLineSize(1);
183  if (size > (unsigned) cacheLineSize / 2)
184    return cacheLineSize;
185  else
186    for (unsigned sz=1; /*no condition*/; sz *= 2)
187      if (sz >= size || sz >= target.DataLayout.getDoubleAlignment())
188        return sz;
189}
190
191
192/*ctor*/
193MachineFunction::MachineFunction(const Function *F,
194                                           const TargetMachine& target)
195  : Annotation(MCFM_AID),
196    method(F), staticStackSize(0),
197    automaticVarsSize(0), regSpillsSize(0),
198    maxOptionalArgsSize(0), maxOptionalNumArgs(0),
199    currentTmpValuesSize(0), maxTmpValuesSize(0), compiledAsLeaf(false),
200    spillsAreaFrozen(false), automaticVarsAreaFrozen(false)
201{
202  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(target, method,
203                                                   maxOptionalNumArgs);
204  staticStackSize = maxOptionalArgsSize
205                    + target.getFrameInfo().getMinStackFrameSize();
206}
207
208int
209MachineFunction::computeOffsetforLocalVar(const TargetMachine& target,
210                                               const Value* val,
211                                               unsigned int& getPaddedSize,
212                                               unsigned int  sizeToUse)
213{
214  if (sizeToUse == 0)
215    sizeToUse = target.findOptimalStorageSize(val->getType());
216  unsigned int align = SizeToAlignment(sizeToUse, target);
217
218  bool growUp;
219  int firstOffset = target.getFrameInfo().getFirstAutomaticVarOffset(*this,
220                                                                     growUp);
221  int offset = growUp? firstOffset + getAutomaticVarsSize()
222                     : firstOffset - (getAutomaticVarsSize() + sizeToUse);
223
224  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
225  getPaddedSize = sizeToUse + abs(aligned - offset);
226
227  return aligned;
228}
229
230int
231MachineFunction::allocateLocalVar(const TargetMachine& target,
232                                       const Value* val,
233                                       unsigned int sizeToUse)
234{
235  assert(! automaticVarsAreaFrozen &&
236         "Size of auto vars area has been used to compute an offset so "
237         "no more automatic vars should be allocated!");
238
239  // Check if we've allocated a stack slot for this value already
240  //
241  int offset = getOffset(val);
242  if (offset == INVALID_FRAME_OFFSET)
243    {
244      unsigned int getPaddedSize;
245      offset = computeOffsetforLocalVar(target, val, getPaddedSize, sizeToUse);
246      offsets[val] = offset;
247      incrementAutomaticVarsSize(getPaddedSize);
248    }
249  return offset;
250}
251
252int
253MachineFunction::allocateSpilledValue(const TargetMachine& target,
254                                           const Type* type)
255{
256  assert(! spillsAreaFrozen &&
257         "Size of reg spills area has been used to compute an offset so "
258         "no more register spill slots should be allocated!");
259
260  unsigned int size  = target.DataLayout.getTypeSize(type);
261  unsigned char align = target.DataLayout.getTypeAlignment(type);
262
263  bool growUp;
264  int firstOffset = target.getFrameInfo().getRegSpillAreaOffset(*this, growUp);
265
266  int offset = growUp? firstOffset + getRegSpillsSize()
267                     : firstOffset - (getRegSpillsSize() + size);
268
269  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
270  size += abs(aligned - offset); // include alignment padding in size
271
272  incrementRegSpillsSize(size);  // update size of reg. spills area
273
274  return aligned;
275}
276
277int
278MachineFunction::pushTempValue(const TargetMachine& target,
279                                    unsigned int size)
280{
281  unsigned int align = SizeToAlignment(size, target);
282
283  bool growUp;
284  int firstOffset = target.getFrameInfo().getTmpAreaOffset(*this, growUp);
285
286  int offset = growUp? firstOffset + currentTmpValuesSize
287                     : firstOffset - (currentTmpValuesSize + size);
288
289  int aligned = target.getFrameInfo().adjustAlignment(offset, growUp, align);
290  size += abs(aligned - offset); // include alignment padding in size
291
292  incrementTmpAreaSize(size);    // update "current" size of tmp area
293
294  return aligned;
295}
296
297void
298MachineFunction::popAllTempValues(const TargetMachine& target)
299{
300  resetTmpAreaSize();            // clear tmp area to reuse
301}
302
303int
304MachineFunction::getOffset(const Value* val) const
305{
306  hash_map<const Value*, int>::const_iterator pair = offsets.find(val);
307  return (pair == offsets.end()) ? INVALID_FRAME_OFFSET : pair->second;
308}
309
310void
311MachineFunction::dump() const
312{
313  std::cerr << "\n" << method->getReturnType()
314            << " \"" << method->getName() << "\"\n";
315
316  for (Function::const_iterator BB = method->begin(); BB != method->end(); ++BB)
317    {
318      std::cerr << "\n" << BB->getName() << " (" << (const void*)BB
319                << ")" << ":" << "\n";
320      MachineBasicBlock& mvec = MachineBasicBlock::get(BB);
321      for (unsigned i=0; i < mvec.size(); i++)
322	std::cerr << "\t" << *mvec[i];
323    }
324  std::cerr << "\nEnd function \"" << method->getName() << "\"\n\n";
325}
326