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"
27 using namespace llvm;
28 using namespace llvm::dwarf;
29 
30 // Handle the Pass registration stuff necessary to use TargetData's.
31 static RegisterPass<MachineModuleInfo>
32 X("machinemoduleinfo", "Module Information");
33 char MachineModuleInfo::ID = 0;
34 
35 // Out of line virtual method.
36 MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
37 
38 //===----------------------------------------------------------------------===//
39 
40 MachineModuleInfo::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 
50 MachineModuleInfo::~MachineModuleInfo() {
51   delete ObjFileMMI;
52 }
53 
54 /// doInitialization - Initialize the state for a new module.
55 ///
56 bool MachineModuleInfo::doInitialization() {
57   return false;
58 }
59 
60 /// doFinalization - Tear down the state after completion of a module.
61 ///
62 bool MachineModuleInfo::doFinalization() {
63   return false;
64 }
65 
66 /// EndFunction - Discard function meta information.
67 ///
68 void MachineModuleInfo::EndFunction() {
69   // Clean up frame info.
70   FrameMoves.clear();
71 
72   // Clean up exception info.
73   LandingPads.clear();
74   CallSiteMap.clear();
75   TypeInfos.clear();
76   FilterIds.clear();
77   FilterEnds.clear();
78   CallsEHReturn = 0;
79   CallsUnwindInit = 0;
80   VariableDbgInfo.clear();
81 }
82 
83 /// AnalyzeModule - Scan the module for global debug information.
84 ///
85 void MachineModuleInfo::AnalyzeModule(Module &M) {
86   // Insert functions in the llvm.used array (but not llvm.compiler.used) into
87   // UsedFunctions.
88   GlobalVariable *GV = M.getGlobalVariable("llvm.used");
89   if (!GV || !GV->hasInitializer()) return;
90 
91   // Should be an array of 'i8*'.
92   ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
93   if (InitList == 0) return;
94 
95   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
96     if (Function *F =
97           dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
98       UsedFunctions.insert(F);
99 }
100 
101 //===-EH-------------------------------------------------------------------===//
102 
103 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
104 /// specified MachineBasicBlock.
105 LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
106     (MachineBasicBlock *LandingPad) {
107   unsigned N = LandingPads.size();
108   for (unsigned i = 0; i < N; ++i) {
109     LandingPadInfo &LP = LandingPads[i];
110     if (LP.LandingPadBlock == LandingPad)
111       return LP;
112   }
113 
114   LandingPads.push_back(LandingPadInfo(LandingPad));
115   return LandingPads[N];
116 }
117 
118 /// addInvoke - Provide the begin and end labels of an invoke style call and
119 /// associate it with a try landing pad block.
120 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
121                                   unsigned BeginLabel, unsigned EndLabel) {
122   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
123   LP.BeginLabels.push_back(BeginLabel);
124   LP.EndLabels.push_back(EndLabel);
125 }
126 
127 /// addLandingPad - Provide the label of a try LandingPad block.
128 ///
129 unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
130   unsigned LandingPadLabel = NextLabelID();
131   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
132   LP.LandingPadLabel = LandingPadLabel;
133   return LandingPadLabel;
134 }
135 
136 /// addPersonality - Provide the personality function for the exception
137 /// information.
138 void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
139                                        Function *Personality) {
140   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
141   LP.Personality = Personality;
142 
143   for (unsigned i = 0; i < Personalities.size(); ++i)
144     if (Personalities[i] == Personality)
145       return;
146 
147   // If this is the first personality we're adding go
148   // ahead and add it at the beginning.
149   if (Personalities[0] == NULL)
150     Personalities[0] = Personality;
151   else
152     Personalities.push_back(Personality);
153 }
154 
155 /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
156 ///
157 void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
158                                         std::vector<GlobalVariable *> &TyInfo) {
159   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
160   for (unsigned N = TyInfo.size(); N; --N)
161     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
162 }
163 
164 /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
165 ///
166 void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
167                                         std::vector<GlobalVariable *> &TyInfo) {
168   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
169   std::vector<unsigned> IdsInFilter(TyInfo.size());
170   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
171     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
172   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
173 }
174 
175 /// addCleanup - Add a cleanup action for a landing pad.
176 ///
177 void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
178   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
179   LP.TypeIds.push_back(0);
180 }
181 
182 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
183 /// pads.
184 void MachineModuleInfo::TidyLandingPads() {
185   for (unsigned i = 0; i != LandingPads.size(); ) {
186     LandingPadInfo &LandingPad = LandingPads[i];
187     LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);
188 
189     // Special case: we *should* emit LPs with null LP MBB. This indicates
190     // "nounwind" case.
191     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
192       LandingPads.erase(LandingPads.begin() + i);
193       continue;
194     }
195 
196     for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
197       unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
198       unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);
199 
200       if (!BeginLabel || !EndLabel) {
201         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
202         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
203         continue;
204       }
205 
206       LandingPad.BeginLabels[j] = BeginLabel;
207       LandingPad.EndLabels[j] = EndLabel;
208       ++j;
209     }
210 
211     // Remove landing pads with no try-ranges.
212     if (LandingPads[i].BeginLabels.empty()) {
213       LandingPads.erase(LandingPads.begin() + i);
214       continue;
215     }
216 
217     // If there is no landing pad, ensure that the list of typeids is empty.
218     // If the only typeid is a cleanup, this is the same as having no typeids.
219     if (!LandingPad.LandingPadBlock ||
220         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
221       LandingPad.TypeIds.clear();
222 
223     ++i;
224   }
225 }
226 
227 /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
228 /// function wide.
229 unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
230   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
231     if (TypeInfos[i] == TI) return i + 1;
232 
233   TypeInfos.push_back(TI);
234   return TypeInfos.size();
235 }
236 
237 /// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
238 /// function wide.
239 int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
240   // If the new filter coincides with the tail of an existing filter, then
241   // re-use the existing filter.  Folding filters more than this requires
242   // re-ordering filters and/or their elements - probably not worth it.
243   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
244        E = FilterEnds.end(); I != E; ++I) {
245     unsigned i = *I, j = TyIds.size();
246 
247     while (i && j)
248       if (FilterIds[--i] != TyIds[--j])
249         goto try_next;
250 
251     if (!j)
252       // The new filter coincides with range [i, end) of the existing filter.
253       return -(1 + i);
254 
255 try_next:;
256   }
257 
258   // Add the new filter.
259   int FilterID = -(1 + FilterIds.size());
260   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
261   for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
262     FilterIds.push_back(TyIds[I]);
263   FilterEnds.push_back(FilterIds.size());
264   FilterIds.push_back(0); // terminator
265   return FilterID;
266 }
267 
268 /// getPersonality - Return the personality function for the current function.
269 Function *MachineModuleInfo::getPersonality() const {
270   // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
271   // function
272   return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
273 }
274 
275 /// getPersonalityIndex - Return unique index for current personality
276 /// function. NULL/first personality function should always get zero index.
277 unsigned MachineModuleInfo::getPersonalityIndex() const {
278   const Function* Personality = NULL;
279 
280   // Scan landing pads. If there is at least one non-NULL personality - use it.
281   for (unsigned i = 0; i != LandingPads.size(); ++i)
282     if (LandingPads[i].Personality) {
283       Personality = LandingPads[i].Personality;
284       break;
285     }
286 
287   for (unsigned i = 0; i < Personalities.size(); ++i) {
288     if (Personalities[i] == Personality)
289       return i;
290   }
291 
292   // This will happen if the current personality function is
293   // in the zero index.
294   return 0;
295 }
296 
297