MachineModuleInfo.cpp revision fdc826f6e834a2da80965a34f2ffb5d869fd8c64 
1//===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/CodeGen/MachineModuleInfo.h"
11
12#include "llvm/Constants.h"
13#include "llvm/Analysis/ValueTracking.h"
14#include "llvm/CodeGen/MachineFunctionPass.h"
15#include "llvm/CodeGen/MachineFunction.h"
16#include "llvm/CodeGen/Passes.h"
17#include "llvm/Target/TargetInstrInfo.h"
18#include "llvm/Target/TargetMachine.h"
19#include "llvm/Target/TargetOptions.h"
20#include "llvm/DerivedTypes.h"
21#include "llvm/GlobalVariable.h"
22#include "llvm/Intrinsics.h"
23#include "llvm/Instructions.h"
24#include "llvm/Module.h"
25#include "llvm/Support/Dwarf.h"
26#include "llvm/Support/ErrorHandling.h"
27using namespace llvm;
28using namespace llvm::dwarf;
29
30// Handle the Pass registration stuff necessary to use TargetData's.
31static RegisterPass<MachineModuleInfo>
32X("machinemoduleinfo", "Module Information");
33char MachineModuleInfo::ID = 0;
34
35// Out of line virtual method.
36MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
37
38//===----------------------------------------------------------------------===//
39
40MachineModuleInfo::MachineModuleInfo()
41: ImmutablePass(&ID)
42, ObjFileMMI(0)
43, CallsEHReturn(0)
44, CallsUnwindInit(0)
45, DbgInfoAvailable(false) {
46  // Always emit some info, by default "no personality" info.
47  Personalities.push_back(NULL);
48}
49
50MachineModuleInfo::~MachineModuleInfo() {
51  delete ObjFileMMI;
52}
53
54/// doInitialization - Initialize the state for a new module.
55///
56bool MachineModuleInfo::doInitialization() {
57  return false;
58}
59
60/// doFinalization - Tear down the state after completion of a module.
61///
62bool MachineModuleInfo::doFinalization() {
63  return false;
64}
65
66/// EndFunction - Discard function meta information.
67///
68void MachineModuleInfo::EndFunction() {
69  // Clean up frame info.
70  FrameMoves.clear();
71
72  // Clean up exception info.
73  LandingPads.clear();
74  TypeInfos.clear();
75  FilterIds.clear();
76  FilterEnds.clear();
77  CallsEHReturn = 0;
78  CallsUnwindInit = 0;
79}
80
81/// AnalyzeModule - Scan the module for global debug information.
82///
83void MachineModuleInfo::AnalyzeModule(Module &M) {
84  // Insert functions in the llvm.used array (but not llvm.compiler.used) into
85  // UsedFunctions.
86  GlobalVariable *GV = M.getGlobalVariable("llvm.used");
87  if (!GV || !GV->hasInitializer()) return;
88
89  // Should be an array of 'i8*'.
90  ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
91  if (InitList == 0) return;
92
93  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
94    if (Function *F =
95          dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
96      UsedFunctions.insert(F);
97}
98
99//===-EH-------------------------------------------------------------------===//
100
101/// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
102/// specified MachineBasicBlock.
103LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
104    (MachineBasicBlock *LandingPad) {
105  unsigned N = LandingPads.size();
106  for (unsigned i = 0; i < N; ++i) {
107    LandingPadInfo &LP = LandingPads[i];
108    if (LP.LandingPadBlock == LandingPad)
109      return LP;
110  }
111
112  LandingPads.push_back(LandingPadInfo(LandingPad));
113  return LandingPads[N];
114}
115
116/// addInvoke - Provide the begin and end labels of an invoke style call and
117/// associate it with a try landing pad block.
118void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
119                                  unsigned BeginLabel, unsigned EndLabel) {
120  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
121  LP.BeginLabels.push_back(BeginLabel);
122  LP.EndLabels.push_back(EndLabel);
123}
124
125/// addLandingPad - Provide the label of a try LandingPad block.
126///
127unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
128  unsigned LandingPadLabel = NextLabelID();
129  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
130  LP.LandingPadLabel = LandingPadLabel;
131  return LandingPadLabel;
132}
133
134/// addPersonality - Provide the personality function for the exception
135/// information.
136void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
137                                       Function *Personality) {
138  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
139  LP.Personality = Personality;
140
141  for (unsigned i = 0; i < Personalities.size(); ++i)
142    if (Personalities[i] == Personality)
143      return;
144
145  // If this is the first personality we're adding go
146  // ahead and add it at the beginning.
147  if (Personalities[0] == NULL)
148    Personalities[0] = Personality;
149  else
150    Personalities.push_back(Personality);
151}
152
153/// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
154///
155void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
156                                        std::vector<GlobalVariable *> &TyInfo) {
157  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
158  for (unsigned N = TyInfo.size(); N; --N)
159    LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
160}
161
162/// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
163///
164void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
165                                        std::vector<GlobalVariable *> &TyInfo) {
166  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
167  std::vector<unsigned> IdsInFilter(TyInfo.size());
168  for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
169    IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
170  LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
171}
172
173/// addCleanup - Add a cleanup action for a landing pad.
174///
175void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
176  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
177  LP.TypeIds.push_back(0);
178}
179
180/// TidyLandingPads - Remap landing pad labels and remove any deleted landing
181/// pads.
182void MachineModuleInfo::TidyLandingPads() {
183  for (unsigned i = 0; i != LandingPads.size(); ) {
184    LandingPadInfo &LandingPad = LandingPads[i];
185    LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);
186
187    // Special case: we *should* emit LPs with null LP MBB. This indicates
188    // "nounwind" case.
189    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
190      LandingPads.erase(LandingPads.begin() + i);
191      continue;
192    }
193
194    for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
195      unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
196      unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);
197
198      if (!BeginLabel || !EndLabel) {
199        LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
200        LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
201        continue;
202      }
203
204      LandingPad.BeginLabels[j] = BeginLabel;
205      LandingPad.EndLabels[j] = EndLabel;
206      ++j;
207    }
208
209    // Remove landing pads with no try-ranges.
210    if (LandingPads[i].BeginLabels.empty()) {
211      LandingPads.erase(LandingPads.begin() + i);
212      continue;
213    }
214
215    // If there is no landing pad, ensure that the list of typeids is empty.
216    // If the only typeid is a cleanup, this is the same as having no typeids.
217    if (!LandingPad.LandingPadBlock ||
218        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
219      LandingPad.TypeIds.clear();
220
221    ++i;
222  }
223}
224
225/// getTypeIDFor - Return the type id for the specified typeinfo.  This is
226/// function wide.
227unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
228  for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
229    if (TypeInfos[i] == TI) return i + 1;
230
231  TypeInfos.push_back(TI);
232  return TypeInfos.size();
233}
234
235/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
236/// function wide.
237int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
238  // If the new filter coincides with the tail of an existing filter, then
239  // re-use the existing filter.  Folding filters more than this requires
240  // re-ordering filters and/or their elements - probably not worth it.
241  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
242       E = FilterEnds.end(); I != E; ++I) {
243    unsigned i = *I, j = TyIds.size();
244
245    while (i && j)
246      if (FilterIds[--i] != TyIds[--j])
247        goto try_next;
248
249    if (!j)
250      // The new filter coincides with range [i, end) of the existing filter.
251      return -(1 + i);
252
253try_next:;
254  }
255
256  // Add the new filter.
257  int FilterID = -(1 + FilterIds.size());
258  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
259  for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
260    FilterIds.push_back(TyIds[I]);
261  FilterEnds.push_back(FilterIds.size());
262  FilterIds.push_back(0); // terminator
263  return FilterID;
264}
265
266/// getPersonality - Return the personality function for the current function.
267Function *MachineModuleInfo::getPersonality() const {
268  // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
269  // function
270  return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
271}
272
273/// getPersonalityIndex - Return unique index for current personality
274/// function. NULL/first personality function should always get zero index.
275unsigned MachineModuleInfo::getPersonalityIndex() const {
276  const Function* Personality = NULL;
277
278  // Scan landing pads. If there is at least one non-NULL personality - use it.
279  for (unsigned i = 0; i != LandingPads.size(); ++i)
280    if (LandingPads[i].Personality) {
281      Personality = LandingPads[i].Personality;
282      break;
283    }
284
285  for (unsigned i = 0; i < Personalities.size(); ++i) {
286    if (Personalities[i] == Personality)
287      return i;
288  }
289
290  // This will happen if the current personality function is
291  // in the zero index.
292  return 0;
293}
294
295//===----------------------------------------------------------------------===//
296/// DebugLabelFolding pass - This pass prunes out redundant labels.  This allows
297/// a info consumer to determine if the range of two labels is empty, by seeing
298/// if the labels map to the same reduced label.
299
300namespace llvm {
301
302struct DebugLabelFolder : public MachineFunctionPass {
303  static char ID;
304  DebugLabelFolder() : MachineFunctionPass(&ID) {}
305
306  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
307    AU.setPreservesCFG();
308    AU.addPreservedID(MachineLoopInfoID);
309    AU.addPreservedID(MachineDominatorsID);
310    MachineFunctionPass::getAnalysisUsage(AU);
311  }
312
313  virtual bool runOnMachineFunction(MachineFunction &MF);
314  virtual const char *getPassName() const { return "Label Folder"; }
315};
316
317char DebugLabelFolder::ID = 0;
318
319bool DebugLabelFolder::runOnMachineFunction(MachineFunction &MF) {
320  // Get machine module info.
321  MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
322  if (!MMI) return false;
323
324  // Track if change is made.
325  bool MadeChange = false;
326  // No prior label to begin.
327  unsigned PriorLabel = 0;
328
329  // Iterate through basic blocks.
330  for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
331       BB != E; ++BB) {
332    // Iterate through instructions.
333    for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
334      // Is it a label.
335      if (I->isDebugLabel() && !MMI->isDbgLabelUsed(I->getOperand(0).getImm())){
336        // The label ID # is always operand #0, an immediate.
337        unsigned NextLabel = I->getOperand(0).getImm();
338
339        // If there was an immediate prior label.
340        if (PriorLabel) {
341          // Remap the current label to prior label.
342          MMI->RemapLabel(NextLabel, PriorLabel);
343          // Delete the current label.
344          I = BB->erase(I);
345          // Indicate a change has been made.
346          MadeChange = true;
347          continue;
348        } else {
349          // Start a new round.
350          PriorLabel = NextLabel;
351        }
352       } else {
353        // No consecutive labels.
354        PriorLabel = 0;
355      }
356
357      ++I;
358    }
359  }
360
361  return MadeChange;
362}
363
364FunctionPass *createDebugLabelFoldingPass() { return new DebugLabelFolder(); }
365
366}
367