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 #include "llvm/ADT/ArrayRef.h"
12 #include "llvm/ADT/DenseMap.h"
13 #include "llvm/ADT/PostOrderIterator.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/ADT/TinyPtrVector.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/IR/BasicBlock.h"
19 #include "llvm/IR/DerivedTypes.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/Value.h"
23 #include "llvm/IR/ValueHandle.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCSymbol.h"
26 #include "llvm/Pass.h"
27 #include "llvm/Support/Casting.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Target/TargetLoweringObjectFile.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include <algorithm>
32 #include <cassert>
33 #include <memory>
34 #include <utility>
35 #include <vector>
36
37 using namespace llvm;
38 using namespace llvm::dwarf;
39
40 // Handle the Pass registration stuff necessary to use DataLayout's.
41 INITIALIZE_PASS(MachineModuleInfo, "machinemoduleinfo",
42 "Machine Module Information", false, false)
43 char MachineModuleInfo::ID = 0;
44
45 // Out of line virtual method.
46 MachineModuleInfoImpl::~MachineModuleInfoImpl() = default;
47
48 namespace llvm {
49
50 class MMIAddrLabelMapCallbackPtr final : CallbackVH {
51 MMIAddrLabelMap *Map = nullptr;
52
53 public:
54 MMIAddrLabelMapCallbackPtr() = default;
MMIAddrLabelMapCallbackPtr(Value * V)55 MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V) {}
56
setPtr(BasicBlock * BB)57 void setPtr(BasicBlock *BB) {
58 ValueHandleBase::operator=(BB);
59 }
60
setMap(MMIAddrLabelMap * map)61 void setMap(MMIAddrLabelMap *map) { Map = map; }
62
63 void deleted() override;
64 void allUsesReplacedWith(Value *V2) override;
65 };
66
67 class MMIAddrLabelMap {
68 MCContext &Context;
69 struct AddrLabelSymEntry {
70 /// The symbols for the label.
71 TinyPtrVector<MCSymbol *> Symbols;
72
73 Function *Fn; // The containing function of the BasicBlock.
74 unsigned Index; // The index in BBCallbacks for the BasicBlock.
75 };
76
77 DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
78
79 /// Callbacks for the BasicBlock's that we have entries for. We use this so
80 /// we get notified if a block is deleted or RAUWd.
81 std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
82
83 /// This is a per-function list of symbols whose corresponding BasicBlock got
84 /// deleted. These symbols need to be emitted at some point in the file, so
85 /// AsmPrinter emits them after the function body.
86 DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>
87 DeletedAddrLabelsNeedingEmission;
88
89 public:
MMIAddrLabelMap(MCContext & context)90 MMIAddrLabelMap(MCContext &context) : Context(context) {}
91
~MMIAddrLabelMap()92 ~MMIAddrLabelMap() {
93 assert(DeletedAddrLabelsNeedingEmission.empty() &&
94 "Some labels for deleted blocks never got emitted");
95 }
96
97 ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);
98
99 void takeDeletedSymbolsForFunction(Function *F,
100 std::vector<MCSymbol*> &Result);
101
102 void UpdateForDeletedBlock(BasicBlock *BB);
103 void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
104 };
105
106 } // end namespace llvm
107
getAddrLabelSymbolToEmit(BasicBlock * BB)108 ArrayRef<MCSymbol *> MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
109 assert(BB->hasAddressTaken() &&
110 "Shouldn't get label for block without address taken");
111 AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
112
113 // If we already had an entry for this block, just return it.
114 if (!Entry.Symbols.empty()) {
115 assert(BB->getParent() == Entry.Fn && "Parent changed");
116 return Entry.Symbols;
117 }
118
119 // Otherwise, this is a new entry, create a new symbol for it and add an
120 // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
121 BBCallbacks.emplace_back(BB);
122 BBCallbacks.back().setMap(this);
123 Entry.Index = BBCallbacks.size() - 1;
124 Entry.Fn = BB->getParent();
125 Entry.Symbols.push_back(Context.createTempSymbol());
126 return Entry.Symbols;
127 }
128
129 /// If we have any deleted symbols for F, return them.
130 void MMIAddrLabelMap::
takeDeletedSymbolsForFunction(Function * F,std::vector<MCSymbol * > & Result)131 takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
132 DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>::iterator I =
133 DeletedAddrLabelsNeedingEmission.find(F);
134
135 // If there are no entries for the function, just return.
136 if (I == DeletedAddrLabelsNeedingEmission.end()) return;
137
138 // Otherwise, take the list.
139 std::swap(Result, I->second);
140 DeletedAddrLabelsNeedingEmission.erase(I);
141 }
142
UpdateForDeletedBlock(BasicBlock * BB)143 void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
144 // If the block got deleted, there is no need for the symbol. If the symbol
145 // was already emitted, we can just forget about it, otherwise we need to
146 // queue it up for later emission when the function is output.
147 AddrLabelSymEntry Entry = std::move(AddrLabelSymbols[BB]);
148 AddrLabelSymbols.erase(BB);
149 assert(!Entry.Symbols.empty() && "Didn't have a symbol, why a callback?");
150 BBCallbacks[Entry.Index] = nullptr; // Clear the callback.
151
152 assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
153 "Block/parent mismatch");
154
155 for (MCSymbol *Sym : Entry.Symbols) {
156 if (Sym->isDefined())
157 return;
158
159 // If the block is not yet defined, we need to emit it at the end of the
160 // function. Add the symbol to the DeletedAddrLabelsNeedingEmission list
161 // for the containing Function. Since the block is being deleted, its
162 // parent may already be removed, we have to get the function from 'Entry'.
163 DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
164 }
165 }
166
UpdateForRAUWBlock(BasicBlock * Old,BasicBlock * New)167 void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
168 // Get the entry for the RAUW'd block and remove it from our map.
169 AddrLabelSymEntry OldEntry = std::move(AddrLabelSymbols[Old]);
170 AddrLabelSymbols.erase(Old);
171 assert(!OldEntry.Symbols.empty() && "Didn't have a symbol, why a callback?");
172
173 AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
174
175 // If New is not address taken, just move our symbol over to it.
176 if (NewEntry.Symbols.empty()) {
177 BBCallbacks[OldEntry.Index].setPtr(New); // Update the callback.
178 NewEntry = std::move(OldEntry); // Set New's entry.
179 return;
180 }
181
182 BBCallbacks[OldEntry.Index] = nullptr; // Update the callback.
183
184 // Otherwise, we need to add the old symbols to the new block's set.
185 NewEntry.Symbols.insert(NewEntry.Symbols.end(), OldEntry.Symbols.begin(),
186 OldEntry.Symbols.end());
187 }
188
deleted()189 void MMIAddrLabelMapCallbackPtr::deleted() {
190 Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
191 }
192
allUsesReplacedWith(Value * V2)193 void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
194 Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
195 }
196
MachineModuleInfo(const TargetMachine * TM)197 MachineModuleInfo::MachineModuleInfo(const TargetMachine *TM)
198 : ImmutablePass(ID), TM(*TM),
199 Context(TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
200 TM->getObjFileLowering(), nullptr, false) {
201 initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
202 }
203
204 MachineModuleInfo::~MachineModuleInfo() = default;
205
doInitialization(Module & M)206 bool MachineModuleInfo::doInitialization(Module &M) {
207 ObjFileMMI = nullptr;
208 CurCallSite = 0;
209 DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
210 HasSplitStack = HasNosplitStack = false;
211 AddrLabelSymbols = nullptr;
212 TheModule = &M;
213 return false;
214 }
215
doFinalization(Module & M)216 bool MachineModuleInfo::doFinalization(Module &M) {
217 Personalities.clear();
218
219 delete AddrLabelSymbols;
220 AddrLabelSymbols = nullptr;
221
222 Context.reset();
223
224 delete ObjFileMMI;
225 ObjFileMMI = nullptr;
226
227 return false;
228 }
229
230 //===- Address of Block Management ----------------------------------------===//
231
232 ArrayRef<MCSymbol *>
getAddrLabelSymbolToEmit(const BasicBlock * BB)233 MachineModuleInfo::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
234 // Lazily create AddrLabelSymbols.
235 if (!AddrLabelSymbols)
236 AddrLabelSymbols = new MMIAddrLabelMap(Context);
237 return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
238 }
239
240 void MachineModuleInfo::
takeDeletedSymbolsForFunction(const Function * F,std::vector<MCSymbol * > & Result)241 takeDeletedSymbolsForFunction(const Function *F,
242 std::vector<MCSymbol*> &Result) {
243 // If no blocks have had their addresses taken, we're done.
244 if (!AddrLabelSymbols) return;
245 return AddrLabelSymbols->
246 takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
247 }
248
249 /// \name Exception Handling
250 /// \{
251
addPersonality(const Function * Personality)252 void MachineModuleInfo::addPersonality(const Function *Personality) {
253 for (unsigned i = 0; i < Personalities.size(); ++i)
254 if (Personalities[i] == Personality)
255 return;
256 Personalities.push_back(Personality);
257 }
258
259 /// \}
260
261 MachineFunction *
getMachineFunction(const Function & F) const262 MachineModuleInfo::getMachineFunction(const Function &F) const {
263 auto I = MachineFunctions.find(&F);
264 return I != MachineFunctions.end() ? I->second.get() : nullptr;
265 }
266
267 MachineFunction &
getOrCreateMachineFunction(const Function & F)268 MachineModuleInfo::getOrCreateMachineFunction(const Function &F) {
269 // Shortcut for the common case where a sequence of MachineFunctionPasses
270 // all query for the same Function.
271 if (LastRequest == &F)
272 return *LastResult;
273
274 auto I = MachineFunctions.insert(
275 std::make_pair(&F, std::unique_ptr<MachineFunction>()));
276 MachineFunction *MF;
277 if (I.second) {
278 // No pre-existing machine function, create a new one.
279 const TargetSubtargetInfo &STI = *TM.getSubtargetImpl(F);
280 MF = new MachineFunction(F, TM, STI, NextFnNum++, *this);
281 // Update the set entry.
282 I.first->second.reset(MF);
283 } else {
284 MF = I.first->second.get();
285 }
286
287 LastRequest = &F;
288 LastResult = MF;
289 return *MF;
290 }
291
deleteMachineFunctionFor(Function & F)292 void MachineModuleInfo::deleteMachineFunctionFor(Function &F) {
293 MachineFunctions.erase(&F);
294 LastRequest = nullptr;
295 LastResult = nullptr;
296 }
297
298 namespace {
299
300 /// This pass frees the MachineFunction object associated with a Function.
301 class FreeMachineFunction : public FunctionPass {
302 public:
303 static char ID;
304
FreeMachineFunction()305 FreeMachineFunction() : FunctionPass(ID) {}
306
getAnalysisUsage(AnalysisUsage & AU) const307 void getAnalysisUsage(AnalysisUsage &AU) const override {
308 AU.addRequired<MachineModuleInfo>();
309 AU.addPreserved<MachineModuleInfo>();
310 }
311
runOnFunction(Function & F)312 bool runOnFunction(Function &F) override {
313 MachineModuleInfo &MMI = getAnalysis<MachineModuleInfo>();
314 MMI.deleteMachineFunctionFor(F);
315 return true;
316 }
317
getPassName() const318 StringRef getPassName() const override {
319 return "Free MachineFunction";
320 }
321 };
322
323 } // end anonymous namespace
324
325 char FreeMachineFunction::ID;
326
createFreeMachineFunctionPass()327 FunctionPass *llvm::createFreeMachineFunctionPass() {
328 return new FreeMachineFunction();
329 }
330
331 //===- MMI building helpers -----------------------------------------------===//
332
computeUsesVAFloatArgument(const CallInst & I,MachineModuleInfo & MMI)333 void llvm::computeUsesVAFloatArgument(const CallInst &I,
334 MachineModuleInfo &MMI) {
335 FunctionType *FT =
336 cast<FunctionType>(I.getCalledValue()->getType()->getContainedType(0));
337 if (FT->isVarArg() && !MMI.usesVAFloatArgument()) {
338 for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) {
339 Type *T = I.getArgOperand(i)->getType();
340 for (auto i : post_order(T)) {
341 if (i->isFloatingPointTy()) {
342 MMI.setUsesVAFloatArgument(true);
343 return;
344 }
345 }
346 }
347 }
348 }
349