MachineModuleInfo.cpp revision bbdc8207d587026212e176026d3e37ae043a6661 
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/Streams.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//===----------------------------------------------------------------------===//
36
37MachineModuleInfo::MachineModuleInfo()
38: ImmutablePass(&ID)
39, Lines()
40, LabelIDList()
41, FrameMoves()
42, LandingPads()
43, Personalities()
44, CallsEHReturn(0)
45, CallsUnwindInit(0)
46, DbgInfoAvailable(false)
47{
48  // Always emit "no personality" info
49  Personalities.push_back(NULL);
50}
51MachineModuleInfo::~MachineModuleInfo() {
52
53}
54
55/// doInitialization - Initialize the state for a new module.
56///
57bool MachineModuleInfo::doInitialization() {
58  return false;
59}
60
61/// doFinalization - Tear down the state after completion of a module.
62///
63bool MachineModuleInfo::doFinalization() {
64  return false;
65}
66
67/// BeginFunction - Begin gathering function meta information.
68///
69void MachineModuleInfo::BeginFunction(MachineFunction *MF) {
70  // Coming soon.
71}
72
73/// EndFunction - Discard function meta information.
74///
75void MachineModuleInfo::EndFunction() {
76  // Clean up frame info.
77  FrameMoves.clear();
78
79  // Clean up exception info.
80  LandingPads.clear();
81  TypeInfos.clear();
82  FilterIds.clear();
83  FilterEnds.clear();
84  CallsEHReturn = 0;
85  CallsUnwindInit = 0;
86}
87
88/// AnalyzeModule - Scan the module for global debug information.
89///
90void MachineModuleInfo::AnalyzeModule(Module &M) {
91  // Insert functions in the llvm.used array into UsedFunctions.
92  GlobalVariable *GV = M.getGlobalVariable("llvm.used");
93  if (!GV || !GV->hasInitializer()) return;
94
95  // Should be an array of 'i8*'.
96  ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
97  if (InitList == 0) return;
98
99  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
100    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(InitList->getOperand(i)))
101      if (CE->getOpcode() == Instruction::BitCast)
102        if (Function *F = dyn_cast<Function>(CE->getOperand(0)))
103          UsedFunctions.insert(F);
104  }
105}
106
107//===-EH-------------------------------------------------------------------===//
108
109/// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
110/// specified MachineBasicBlock.
111LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
112    (MachineBasicBlock *LandingPad) {
113  unsigned N = LandingPads.size();
114  for (unsigned i = 0; i < N; ++i) {
115    LandingPadInfo &LP = LandingPads[i];
116    if (LP.LandingPadBlock == LandingPad)
117      return LP;
118  }
119
120  LandingPads.push_back(LandingPadInfo(LandingPad));
121  return LandingPads[N];
122}
123
124/// addInvoke - Provide the begin and end labels of an invoke style call and
125/// associate it with a try landing pad block.
126void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
127                                  unsigned BeginLabel, unsigned EndLabel) {
128  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
129  LP.BeginLabels.push_back(BeginLabel);
130  LP.EndLabels.push_back(EndLabel);
131}
132
133/// addLandingPad - Provide the label of a try LandingPad block.
134///
135unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
136  unsigned LandingPadLabel = NextLabelID();
137  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
138  LP.LandingPadLabel = LandingPadLabel;
139  return LandingPadLabel;
140}
141
142/// addPersonality - Provide the personality function for the exception
143/// information.
144void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
145                                       Function *Personality) {
146  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
147  LP.Personality = Personality;
148
149  for (unsigned i = 0; i < Personalities.size(); ++i)
150    if (Personalities[i] == Personality)
151      return;
152
153  Personalities.push_back(Personality);
154}
155
156/// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
157///
158void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
159                                        std::vector<GlobalVariable *> &TyInfo) {
160  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
161  for (unsigned N = TyInfo.size(); N; --N)
162    LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
163}
164
165/// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
166///
167void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
168                                        std::vector<GlobalVariable *> &TyInfo) {
169  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
170  std::vector<unsigned> IdsInFilter(TyInfo.size());
171  for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
172    IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
173  LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
174}
175
176/// addCleanup - Add a cleanup action for a landing pad.
177///
178void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
179  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
180  LP.TypeIds.push_back(0);
181}
182
183/// TidyLandingPads - Remap landing pad labels and remove any deleted landing
184/// pads.
185void MachineModuleInfo::TidyLandingPads() {
186  for (unsigned i = 0; i != LandingPads.size(); ) {
187    LandingPadInfo &LandingPad = LandingPads[i];
188    LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);
189
190    // Special case: we *should* emit LPs with null LP MBB. This indicates
191    // "nounwind" case.
192    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
193      LandingPads.erase(LandingPads.begin() + i);
194      continue;
195    }
196
197    for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
198      unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
199      unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);
200
201      if (!BeginLabel || !EndLabel) {
202        LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
203        LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
204        continue;
205      }
206
207      LandingPad.BeginLabels[j] = BeginLabel;
208      LandingPad.EndLabels[j] = EndLabel;
209      ++j;
210    }
211
212    // Remove landing pads with no try-ranges.
213    if (LandingPads[i].BeginLabels.empty()) {
214      LandingPads.erase(LandingPads.begin() + i);
215      continue;
216    }
217
218    // If there is no landing pad, ensure that the list of typeids is empty.
219    // If the only typeid is a cleanup, this is the same as having no typeids.
220    if (!LandingPad.LandingPadBlock ||
221        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
222      LandingPad.TypeIds.clear();
223
224    ++i;
225  }
226}
227
228/// getTypeIDFor - Return the type id for the specified typeinfo.  This is
229/// function wide.
230unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
231  for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
232    if (TypeInfos[i] == TI) return i + 1;
233
234  TypeInfos.push_back(TI);
235  return TypeInfos.size();
236}
237
238/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
239/// function wide.
240int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
241  // If the new filter coincides with the tail of an existing filter, then
242  // re-use the existing filter.  Folding filters more than this requires
243  // re-ordering filters and/or their elements - probably not worth it.
244  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
245       E = FilterEnds.end(); I != E; ++I) {
246    unsigned i = *I, j = TyIds.size();
247
248    while (i && j)
249      if (FilterIds[--i] != TyIds[--j])
250        goto try_next;
251
252    if (!j)
253      // The new filter coincides with range [i, end) of the existing filter.
254      return -(1 + i);
255
256try_next:;
257  }
258
259  // Add the new filter.
260  int FilterID = -(1 + FilterIds.size());
261  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
262  for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
263    FilterIds.push_back(TyIds[I]);
264  FilterEnds.push_back(FilterIds.size());
265  FilterIds.push_back(0); // terminator
266  return FilterID;
267}
268
269/// getPersonality - Return the personality function for the current function.
270Function *MachineModuleInfo::getPersonality() const {
271  // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
272  // function
273  return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
274}
275
276/// getPersonalityIndex - Return unique index for current personality
277/// function. NULL personality function should always get zero index.
278unsigned MachineModuleInfo::getPersonalityIndex() const {
279  const Function* Personality = NULL;
280
281  // Scan landing pads. If there is at least one non-NULL personality - use it.
282  for (unsigned i = 0; i != LandingPads.size(); ++i)
283    if (LandingPads[i].Personality) {
284      Personality = LandingPads[i].Personality;
285      break;
286    }
287
288  for (unsigned i = 0; i < Personalities.size(); ++i) {
289    if (Personalities[i] == Personality)
290      return i;
291  }
292
293  // This should never happen
294  assert(0 && "Personality function should be set!");
295  return 0;
296}
297
298//===----------------------------------------------------------------------===//
299/// DebugLabelFolding pass - This pass prunes out redundant labels.  This allows
300/// a info consumer to determine if the range of two labels is empty, by seeing
301/// if the labels map to the same reduced label.
302
303namespace llvm {
304
305struct DebugLabelFolder : public MachineFunctionPass {
306  static char ID;
307  DebugLabelFolder() : MachineFunctionPass(&ID) {}
308
309  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
310    AU.addPreservedID(MachineLoopInfoID);
311    AU.addPreservedID(MachineDominatorsID);
312    MachineFunctionPass::getAnalysisUsage(AU);
313  }
314
315  virtual bool runOnMachineFunction(MachineFunction &MF);
316  virtual const char *getPassName() const { return "Label Folder"; }
317};
318
319char DebugLabelFolder::ID = 0;
320
321bool DebugLabelFolder::runOnMachineFunction(MachineFunction &MF) {
322  // Get machine module info.
323  MachineModuleInfo *MMI = getAnalysisToUpdate<MachineModuleInfo>();
324  if (!MMI) return false;
325
326  // Track if change is made.
327  bool MadeChange = false;
328  // No prior label to begin.
329  unsigned PriorLabel = 0;
330
331  // Iterate through basic blocks.
332  for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
333       BB != E; ++BB) {
334    // Iterate through instructions.
335    for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
336      // Is it a label.
337      if (I->isDebugLabel()) {
338        // The label ID # is always operand #0, an immediate.
339        unsigned NextLabel = I->getOperand(0).getImm();
340
341        // If there was an immediate prior label.
342        if (PriorLabel) {
343          // Remap the current label to prior label.
344          MMI->RemapLabel(NextLabel, PriorLabel);
345          // Delete the current label.
346          I = BB->erase(I);
347          // Indicate a change has been made.
348          MadeChange = true;
349          continue;
350        } else {
351          // Start a new round.
352          PriorLabel = NextLabel;
353        }
354       } else {
355        // No consecutive labels.
356        PriorLabel = 0;
357      }
358
359      ++I;
360    }
361  }
362
363  return MadeChange;
364}
365
366FunctionPass *createDebugLabelFoldingPass() { return new DebugLabelFolder(); }
367
368}
369
370