File: | lib/Transforms/IPO/MergeFunctions.cpp |
Warning: | line 726, column 5 Called C++ object pointer is null |
1 | //===- MergeFunctions.cpp - Merge identical functions ---------------------===// | |||
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 | // This pass looks for equivalent functions that are mergable and folds them. | |||
11 | // | |||
12 | // Order relation is defined on set of functions. It was made through | |||
13 | // special function comparison procedure that returns | |||
14 | // 0 when functions are equal, | |||
15 | // -1 when Left function is less than right function, and | |||
16 | // 1 for opposite case. We need total-ordering, so we need to maintain | |||
17 | // four properties on the functions set: | |||
18 | // a <= a (reflexivity) | |||
19 | // if a <= b and b <= a then a = b (antisymmetry) | |||
20 | // if a <= b and b <= c then a <= c (transitivity). | |||
21 | // for all a and b: a <= b or b <= a (totality). | |||
22 | // | |||
23 | // Comparison iterates through each instruction in each basic block. | |||
24 | // Functions are kept on binary tree. For each new function F we perform | |||
25 | // lookup in binary tree. | |||
26 | // In practice it works the following way: | |||
27 | // -- We define Function* container class with custom "operator<" (FunctionPtr). | |||
28 | // -- "FunctionPtr" instances are stored in std::set collection, so every | |||
29 | // std::set::insert operation will give you result in log(N) time. | |||
30 | // | |||
31 | // As an optimization, a hash of the function structure is calculated first, and | |||
32 | // two functions are only compared if they have the same hash. This hash is | |||
33 | // cheap to compute, and has the property that if function F == G according to | |||
34 | // the comparison function, then hash(F) == hash(G). This consistency property | |||
35 | // is critical to ensuring all possible merging opportunities are exploited. | |||
36 | // Collisions in the hash affect the speed of the pass but not the correctness | |||
37 | // or determinism of the resulting transformation. | |||
38 | // | |||
39 | // When a match is found the functions are folded. If both functions are | |||
40 | // overridable, we move the functionality into a new internal function and | |||
41 | // leave two overridable thunks to it. | |||
42 | // | |||
43 | //===----------------------------------------------------------------------===// | |||
44 | // | |||
45 | // Future work: | |||
46 | // | |||
47 | // * virtual functions. | |||
48 | // | |||
49 | // Many functions have their address taken by the virtual function table for | |||
50 | // the object they belong to. However, as long as it's only used for a lookup | |||
51 | // and call, this is irrelevant, and we'd like to fold such functions. | |||
52 | // | |||
53 | // * be smarter about bitcasts. | |||
54 | // | |||
55 | // In order to fold functions, we will sometimes add either bitcast instructions | |||
56 | // or bitcast constant expressions. Unfortunately, this can confound further | |||
57 | // analysis since the two functions differ where one has a bitcast and the | |||
58 | // other doesn't. We should learn to look through bitcasts. | |||
59 | // | |||
60 | // * Compare complex types with pointer types inside. | |||
61 | // * Compare cross-reference cases. | |||
62 | // * Compare complex expressions. | |||
63 | // | |||
64 | // All the three issues above could be described as ability to prove that | |||
65 | // fA == fB == fC == fE == fF == fG in example below: | |||
66 | // | |||
67 | // void fA() { | |||
68 | // fB(); | |||
69 | // } | |||
70 | // void fB() { | |||
71 | // fA(); | |||
72 | // } | |||
73 | // | |||
74 | // void fE() { | |||
75 | // fF(); | |||
76 | // } | |||
77 | // void fF() { | |||
78 | // fG(); | |||
79 | // } | |||
80 | // void fG() { | |||
81 | // fE(); | |||
82 | // } | |||
83 | // | |||
84 | // Simplest cross-reference case (fA <--> fB) was implemented in previous | |||
85 | // versions of MergeFunctions, though it presented only in two function pairs | |||
86 | // in test-suite (that counts >50k functions) | |||
87 | // Though possibility to detect complex cross-referencing (e.g.: A->B->C->D->A) | |||
88 | // could cover much more cases. | |||
89 | // | |||
90 | //===----------------------------------------------------------------------===// | |||
91 | ||||
92 | #include "llvm/ADT/Hashing.h" | |||
93 | #include "llvm/ADT/STLExtras.h" | |||
94 | #include "llvm/ADT/SmallSet.h" | |||
95 | #include "llvm/ADT/Statistic.h" | |||
96 | #include "llvm/IR/CallSite.h" | |||
97 | #include "llvm/IR/Constants.h" | |||
98 | #include "llvm/IR/DataLayout.h" | |||
99 | #include "llvm/IR/DebugInfo.h" | |||
100 | #include "llvm/IR/IRBuilder.h" | |||
101 | #include "llvm/IR/Instructions.h" | |||
102 | #include "llvm/IR/IntrinsicInst.h" | |||
103 | #include "llvm/IR/LLVMContext.h" | |||
104 | #include "llvm/IR/Module.h" | |||
105 | #include "llvm/IR/ValueHandle.h" | |||
106 | #include "llvm/IR/ValueMap.h" | |||
107 | #include "llvm/Pass.h" | |||
108 | #include "llvm/Support/CommandLine.h" | |||
109 | #include "llvm/Support/Debug.h" | |||
110 | #include "llvm/Support/ErrorHandling.h" | |||
111 | #include "llvm/Support/raw_ostream.h" | |||
112 | #include "llvm/Transforms/IPO.h" | |||
113 | #include "llvm/Transforms/Utils/FunctionComparator.h" | |||
114 | #include <vector> | |||
115 | ||||
116 | using namespace llvm; | |||
117 | ||||
118 | #define DEBUG_TYPE"mergefunc" "mergefunc" | |||
119 | ||||
120 | STATISTIC(NumFunctionsMerged, "Number of functions merged")static llvm::Statistic NumFunctionsMerged = {"mergefunc", "NumFunctionsMerged" , "Number of functions merged", {0}, false}; | |||
121 | STATISTIC(NumThunksWritten, "Number of thunks generated")static llvm::Statistic NumThunksWritten = {"mergefunc", "NumThunksWritten" , "Number of thunks generated", {0}, false}; | |||
122 | STATISTIC(NumAliasesWritten, "Number of aliases generated")static llvm::Statistic NumAliasesWritten = {"mergefunc", "NumAliasesWritten" , "Number of aliases generated", {0}, false}; | |||
123 | STATISTIC(NumDoubleWeak, "Number of new functions created")static llvm::Statistic NumDoubleWeak = {"mergefunc", "NumDoubleWeak" , "Number of new functions created", {0}, false}; | |||
124 | ||||
125 | static cl::opt<unsigned> NumFunctionsForSanityCheck( | |||
126 | "mergefunc-sanity", | |||
127 | cl::desc("How many functions in module could be used for " | |||
128 | "MergeFunctions pass sanity check. " | |||
129 | "'0' disables this check. Works only with '-debug' key."), | |||
130 | cl::init(0), cl::Hidden); | |||
131 | ||||
132 | // Under option -mergefunc-preserve-debug-info we: | |||
133 | // - Do not create a new function for a thunk. | |||
134 | // - Retain the debug info for a thunk's parameters (and associated | |||
135 | // instructions for the debug info) from the entry block. | |||
136 | // Note: -debug will display the algorithm at work. | |||
137 | // - Create debug-info for the call (to the shared implementation) made by | |||
138 | // a thunk and its return value. | |||
139 | // - Erase the rest of the function, retaining the (minimally sized) entry | |||
140 | // block to create a thunk. | |||
141 | // - Preserve a thunk's call site to point to the thunk even when both occur | |||
142 | // within the same translation unit, to aid debugability. Note that this | |||
143 | // behaviour differs from the underlying -mergefunc implementation which | |||
144 | // modifies the thunk's call site to point to the shared implementation | |||
145 | // when both occur within the same translation unit. | |||
146 | static cl::opt<bool> | |||
147 | MergeFunctionsPDI("mergefunc-preserve-debug-info", cl::Hidden, | |||
148 | cl::init(false), | |||
149 | cl::desc("Preserve debug info in thunk when mergefunc " | |||
150 | "transformations are made.")); | |||
151 | ||||
152 | namespace { | |||
153 | ||||
154 | class FunctionNode { | |||
155 | mutable AssertingVH<Function> F; | |||
156 | FunctionComparator::FunctionHash Hash; | |||
157 | public: | |||
158 | // Note the hash is recalculated potentially multiple times, but it is cheap. | |||
159 | FunctionNode(Function *F) | |||
160 | : F(F), Hash(FunctionComparator::functionHash(*F)) {} | |||
161 | Function *getFunc() const { return F; } | |||
162 | FunctionComparator::FunctionHash getHash() const { return Hash; } | |||
163 | ||||
164 | /// Replace the reference to the function F by the function G, assuming their | |||
165 | /// implementations are equal. | |||
166 | void replaceBy(Function *G) const { | |||
167 | F = G; | |||
168 | } | |||
169 | ||||
170 | void release() { F = nullptr; } | |||
171 | }; | |||
172 | ||||
173 | /// MergeFunctions finds functions which will generate identical machine code, | |||
174 | /// by considering all pointer types to be equivalent. Once identified, | |||
175 | /// MergeFunctions will fold them by replacing a call to one to a call to a | |||
176 | /// bitcast of the other. | |||
177 | /// | |||
178 | class MergeFunctions : public ModulePass { | |||
179 | public: | |||
180 | static char ID; | |||
181 | MergeFunctions() | |||
182 | : ModulePass(ID), FnTree(FunctionNodeCmp(&GlobalNumbers)), FNodesInTree(), | |||
183 | HasGlobalAliases(false) { | |||
184 | initializeMergeFunctionsPass(*PassRegistry::getPassRegistry()); | |||
185 | } | |||
186 | ||||
187 | bool runOnModule(Module &M) override; | |||
188 | ||||
189 | private: | |||
190 | // The function comparison operator is provided here so that FunctionNodes do | |||
191 | // not need to become larger with another pointer. | |||
192 | class FunctionNodeCmp { | |||
193 | GlobalNumberState* GlobalNumbers; | |||
194 | public: | |||
195 | FunctionNodeCmp(GlobalNumberState* GN) : GlobalNumbers(GN) {} | |||
196 | bool operator()(const FunctionNode &LHS, const FunctionNode &RHS) const { | |||
197 | // Order first by hashes, then full function comparison. | |||
198 | if (LHS.getHash() != RHS.getHash()) | |||
199 | return LHS.getHash() < RHS.getHash(); | |||
200 | FunctionComparator FCmp(LHS.getFunc(), RHS.getFunc(), GlobalNumbers); | |||
201 | return FCmp.compare() == -1; | |||
202 | } | |||
203 | }; | |||
204 | typedef std::set<FunctionNode, FunctionNodeCmp> FnTreeType; | |||
205 | ||||
206 | GlobalNumberState GlobalNumbers; | |||
207 | ||||
208 | /// A work queue of functions that may have been modified and should be | |||
209 | /// analyzed again. | |||
210 | std::vector<WeakTrackingVH> Deferred; | |||
211 | ||||
212 | /// Checks the rules of order relation introduced among functions set. | |||
213 | /// Returns true, if sanity check has been passed, and false if failed. | |||
214 | #ifndef NDEBUG | |||
215 | bool doSanityCheck(std::vector<WeakTrackingVH> &Worklist); | |||
216 | #endif | |||
217 | ||||
218 | /// Insert a ComparableFunction into the FnTree, or merge it away if it's | |||
219 | /// equal to one that's already present. | |||
220 | bool insert(Function *NewFunction); | |||
221 | ||||
222 | /// Remove a Function from the FnTree and queue it up for a second sweep of | |||
223 | /// analysis. | |||
224 | void remove(Function *F); | |||
225 | ||||
226 | /// Find the functions that use this Value and remove them from FnTree and | |||
227 | /// queue the functions. | |||
228 | void removeUsers(Value *V); | |||
229 | ||||
230 | /// Replace all direct calls of Old with calls of New. Will bitcast New if | |||
231 | /// necessary to make types match. | |||
232 | void replaceDirectCallers(Function *Old, Function *New); | |||
233 | ||||
234 | /// Merge two equivalent functions. Upon completion, G may be deleted, or may | |||
235 | /// be converted into a thunk. In either case, it should never be visited | |||
236 | /// again. | |||
237 | void mergeTwoFunctions(Function *F, Function *G); | |||
238 | ||||
239 | /// Replace G with a thunk or an alias to F. Deletes G. | |||
240 | void writeThunkOrAlias(Function *F, Function *G); | |||
241 | ||||
242 | /// Fill PDIUnrelatedWL with instructions from the entry block that are | |||
243 | /// unrelated to parameter related debug info. | |||
244 | void filterInstsUnrelatedToPDI(BasicBlock *GEntryBlock, | |||
245 | std::vector<Instruction *> &PDIUnrelatedWL); | |||
246 | ||||
247 | /// Erase the rest of the CFG (i.e. barring the entry block). | |||
248 | void eraseTail(Function *G); | |||
249 | ||||
250 | /// Erase the instructions in PDIUnrelatedWL as they are unrelated to the | |||
251 | /// parameter debug info, from the entry block. | |||
252 | void eraseInstsUnrelatedToPDI(std::vector<Instruction *> &PDIUnrelatedWL); | |||
253 | ||||
254 | /// Replace G with a simple tail call to bitcast(F). Also (unless | |||
255 | /// MergeFunctionsPDI holds) replace direct uses of G with bitcast(F), | |||
256 | /// delete G. | |||
257 | void writeThunk(Function *F, Function *G); | |||
258 | ||||
259 | /// Replace G with an alias to F. Deletes G. | |||
260 | void writeAlias(Function *F, Function *G); | |||
261 | ||||
262 | /// Replace function F with function G in the function tree. | |||
263 | void replaceFunctionInTree(const FunctionNode &FN, Function *G); | |||
264 | ||||
265 | /// The set of all distinct functions. Use the insert() and remove() methods | |||
266 | /// to modify it. The map allows efficient lookup and deferring of Functions. | |||
267 | FnTreeType FnTree; | |||
268 | // Map functions to the iterators of the FunctionNode which contains them | |||
269 | // in the FnTree. This must be updated carefully whenever the FnTree is | |||
270 | // modified, i.e. in insert(), remove(), and replaceFunctionInTree(), to avoid | |||
271 | // dangling iterators into FnTree. The invariant that preserves this is that | |||
272 | // there is exactly one mapping F -> FN for each FunctionNode FN in FnTree. | |||
273 | ValueMap<Function*, FnTreeType::iterator> FNodesInTree; | |||
274 | ||||
275 | /// Whether or not the target supports global aliases. | |||
276 | bool HasGlobalAliases; | |||
277 | }; | |||
278 | ||||
279 | } // end anonymous namespace | |||
280 | ||||
281 | char MergeFunctions::ID = 0; | |||
282 | INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false)static void *initializeMergeFunctionsPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Merge Functions", "mergefunc" , &MergeFunctions::ID, PassInfo::NormalCtor_t(callDefaultCtor <MergeFunctions>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeMergeFunctionsPassFlag ; void llvm::initializeMergeFunctionsPass(PassRegistry &Registry ) { llvm::call_once(InitializeMergeFunctionsPassFlag, initializeMergeFunctionsPassOnce , std::ref(Registry)); } | |||
283 | ||||
284 | ModulePass *llvm::createMergeFunctionsPass() { | |||
285 | return new MergeFunctions(); | |||
286 | } | |||
287 | ||||
288 | #ifndef NDEBUG | |||
289 | bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) { | |||
290 | if (const unsigned Max = NumFunctionsForSanityCheck) { | |||
291 | unsigned TripleNumber = 0; | |||
292 | bool Valid = true; | |||
293 | ||||
294 | dbgs() << "MERGEFUNC-SANITY: Started for first " << Max << " functions.\n"; | |||
295 | ||||
296 | unsigned i = 0; | |||
297 | for (std::vector<WeakTrackingVH>::iterator I = Worklist.begin(), | |||
298 | E = Worklist.end(); | |||
299 | I != E && i < Max; ++I, ++i) { | |||
300 | unsigned j = i; | |||
301 | for (std::vector<WeakTrackingVH>::iterator J = I; J != E && j < Max; | |||
302 | ++J, ++j) { | |||
303 | Function *F1 = cast<Function>(*I); | |||
304 | Function *F2 = cast<Function>(*J); | |||
305 | int Res1 = FunctionComparator(F1, F2, &GlobalNumbers).compare(); | |||
306 | int Res2 = FunctionComparator(F2, F1, &GlobalNumbers).compare(); | |||
307 | ||||
308 | // If F1 <= F2, then F2 >= F1, otherwise report failure. | |||
309 | if (Res1 != -Res2) { | |||
310 | dbgs() << "MERGEFUNC-SANITY: Non-symmetric; triple: " << TripleNumber | |||
311 | << "\n"; | |||
312 | dbgs() << *F1 << '\n' << *F2 << '\n'; | |||
313 | Valid = false; | |||
314 | } | |||
315 | ||||
316 | if (Res1 == 0) | |||
317 | continue; | |||
318 | ||||
319 | unsigned k = j; | |||
320 | for (std::vector<WeakTrackingVH>::iterator K = J; K != E && k < Max; | |||
321 | ++k, ++K, ++TripleNumber) { | |||
322 | if (K == J) | |||
323 | continue; | |||
324 | ||||
325 | Function *F3 = cast<Function>(*K); | |||
326 | int Res3 = FunctionComparator(F1, F3, &GlobalNumbers).compare(); | |||
327 | int Res4 = FunctionComparator(F2, F3, &GlobalNumbers).compare(); | |||
328 | ||||
329 | bool Transitive = true; | |||
330 | ||||
331 | if (Res1 != 0 && Res1 == Res4) { | |||
332 | // F1 > F2, F2 > F3 => F1 > F3 | |||
333 | Transitive = Res3 == Res1; | |||
334 | } else if (Res3 != 0 && Res3 == -Res4) { | |||
335 | // F1 > F3, F3 > F2 => F1 > F2 | |||
336 | Transitive = Res3 == Res1; | |||
337 | } else if (Res4 != 0 && -Res3 == Res4) { | |||
338 | // F2 > F3, F3 > F1 => F2 > F1 | |||
339 | Transitive = Res4 == -Res1; | |||
340 | } | |||
341 | ||||
342 | if (!Transitive) { | |||
343 | dbgs() << "MERGEFUNC-SANITY: Non-transitive; triple: " | |||
344 | << TripleNumber << "\n"; | |||
345 | dbgs() << "Res1, Res3, Res4: " << Res1 << ", " << Res3 << ", " | |||
346 | << Res4 << "\n"; | |||
347 | dbgs() << *F1 << '\n' << *F2 << '\n' << *F3 << '\n'; | |||
348 | Valid = false; | |||
349 | } | |||
350 | } | |||
351 | } | |||
352 | } | |||
353 | ||||
354 | dbgs() << "MERGEFUNC-SANITY: " << (Valid ? "Passed." : "Failed.") << "\n"; | |||
355 | return Valid; | |||
356 | } | |||
357 | return true; | |||
358 | } | |||
359 | #endif | |||
360 | ||||
361 | bool MergeFunctions::runOnModule(Module &M) { | |||
362 | if (skipModule(M)) | |||
| ||||
363 | return false; | |||
364 | ||||
365 | bool Changed = false; | |||
366 | ||||
367 | // All functions in the module, ordered by hash. Functions with a unique | |||
368 | // hash value are easily eliminated. | |||
369 | std::vector<std::pair<FunctionComparator::FunctionHash, Function *>> | |||
370 | HashedFuncs; | |||
371 | for (Function &Func : M) { | |||
372 | if (!Func.isDeclaration() && !Func.hasAvailableExternallyLinkage()) { | |||
373 | HashedFuncs.push_back({FunctionComparator::functionHash(Func), &Func}); | |||
374 | } | |||
375 | } | |||
376 | ||||
377 | std::stable_sort( | |||
378 | HashedFuncs.begin(), HashedFuncs.end(), | |||
379 | [](const std::pair<FunctionComparator::FunctionHash, Function *> &a, | |||
380 | const std::pair<FunctionComparator::FunctionHash, Function *> &b) { | |||
381 | return a.first < b.first; | |||
382 | }); | |||
383 | ||||
384 | auto S = HashedFuncs.begin(); | |||
385 | for (auto I = HashedFuncs.begin(), IE = HashedFuncs.end(); I != IE; ++I) { | |||
386 | // If the hash value matches the previous value or the next one, we must | |||
387 | // consider merging it. Otherwise it is dropped and never considered again. | |||
388 | if ((I != S && std::prev(I)->first == I->first) || | |||
389 | (std::next(I) != IE && std::next(I)->first == I->first) ) { | |||
390 | Deferred.push_back(WeakTrackingVH(I->second)); | |||
391 | } | |||
392 | } | |||
393 | ||||
394 | do { | |||
395 | std::vector<WeakTrackingVH> Worklist; | |||
396 | Deferred.swap(Worklist); | |||
397 | ||||
398 | DEBUG(doSanityCheck(Worklist))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { doSanityCheck(Worklist); } } while (false); | |||
399 | ||||
400 | DEBUG(dbgs() << "size of module: " << M.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of module: " << M .size() << '\n'; } } while (false); | |||
401 | DEBUG(dbgs() << "size of worklist: " << Worklist.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of worklist: " << Worklist.size() << '\n'; } } while (false); | |||
402 | ||||
403 | // Insert functions and merge them. | |||
404 | for (WeakTrackingVH &I : Worklist) { | |||
405 | if (!I) | |||
406 | continue; | |||
407 | Function *F = cast<Function>(I); | |||
408 | if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage()) { | |||
409 | Changed |= insert(F); | |||
410 | } | |||
411 | } | |||
412 | DEBUG(dbgs() << "size of FnTree: " << FnTree.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of FnTree: " << FnTree .size() << '\n'; } } while (false); | |||
413 | } while (!Deferred.empty()); | |||
414 | ||||
415 | FnTree.clear(); | |||
416 | GlobalNumbers.clear(); | |||
417 | ||||
418 | return Changed; | |||
419 | } | |||
420 | ||||
421 | // Replace direct callers of Old with New. | |||
422 | void MergeFunctions::replaceDirectCallers(Function *Old, Function *New) { | |||
423 | Constant *BitcastNew = ConstantExpr::getBitCast(New, Old->getType()); | |||
424 | for (auto UI = Old->use_begin(), UE = Old->use_end(); UI != UE;) { | |||
425 | Use *U = &*UI; | |||
426 | ++UI; | |||
427 | CallSite CS(U->getUser()); | |||
428 | if (CS && CS.isCallee(U)) { | |||
429 | // Transfer the called function's attributes to the call site. Due to the | |||
430 | // bitcast we will 'lose' ABI changing attributes because the 'called | |||
431 | // function' is no longer a Function* but the bitcast. Code that looks up | |||
432 | // the attributes from the called function will fail. | |||
433 | ||||
434 | // FIXME: This is not actually true, at least not anymore. The callsite | |||
435 | // will always have the same ABI affecting attributes as the callee, | |||
436 | // because otherwise the original input has UB. Note that Old and New | |||
437 | // always have matching ABI, so no attributes need to be changed. | |||
438 | // Transferring other attributes may help other optimizations, but that | |||
439 | // should be done uniformly and not in this ad-hoc way. | |||
440 | auto &Context = New->getContext(); | |||
441 | auto NewPAL = New->getAttributes(); | |||
442 | SmallVector<AttributeSet, 4> NewArgAttrs; | |||
443 | for (unsigned argIdx = 0; argIdx < CS.arg_size(); argIdx++) | |||
444 | NewArgAttrs.push_back(NewPAL.getParamAttributes(argIdx)); | |||
445 | // Don't transfer attributes from the function to the callee. Function | |||
446 | // attributes typically aren't relevant to the calling convention or ABI. | |||
447 | CS.setAttributes(AttributeList::get(Context, /*FnAttrs=*/AttributeSet(), | |||
448 | NewPAL.getRetAttributes(), | |||
449 | NewArgAttrs)); | |||
450 | ||||
451 | remove(CS.getInstruction()->getParent()->getParent()); | |||
452 | U->set(BitcastNew); | |||
453 | } | |||
454 | } | |||
455 | } | |||
456 | ||||
457 | // Replace G with an alias to F if possible, or else a thunk to F. Deletes G. | |||
458 | void MergeFunctions::writeThunkOrAlias(Function *F, Function *G) { | |||
459 | if (HasGlobalAliases && G->hasGlobalUnnamedAddr()) { | |||
460 | if (G->hasExternalLinkage() || G->hasLocalLinkage() || | |||
461 | G->hasWeakLinkage()) { | |||
462 | writeAlias(F, G); | |||
463 | return; | |||
464 | } | |||
465 | } | |||
466 | ||||
467 | writeThunk(F, G); | |||
468 | } | |||
469 | ||||
470 | // Helper for writeThunk, | |||
471 | // Selects proper bitcast operation, | |||
472 | // but a bit simpler then CastInst::getCastOpcode. | |||
473 | static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) { | |||
474 | Type *SrcTy = V->getType(); | |||
475 | if (SrcTy->isStructTy()) { | |||
476 | assert(DestTy->isStructTy())((DestTy->isStructTy()) ? static_cast<void> (0) : __assert_fail ("DestTy->isStructTy()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 476, __PRETTY_FUNCTION__)); | |||
477 | assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements())((SrcTy->getStructNumElements() == DestTy->getStructNumElements ()) ? static_cast<void> (0) : __assert_fail ("SrcTy->getStructNumElements() == DestTy->getStructNumElements()" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 477, __PRETTY_FUNCTION__)); | |||
478 | Value *Result = UndefValue::get(DestTy); | |||
479 | for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) { | |||
480 | Value *Element = createCast( | |||
481 | Builder, Builder.CreateExtractValue(V, makeArrayRef(I)), | |||
482 | DestTy->getStructElementType(I)); | |||
483 | ||||
484 | Result = | |||
485 | Builder.CreateInsertValue(Result, Element, makeArrayRef(I)); | |||
486 | } | |||
487 | return Result; | |||
488 | } | |||
489 | assert(!DestTy->isStructTy())((!DestTy->isStructTy()) ? static_cast<void> (0) : __assert_fail ("!DestTy->isStructTy()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 489, __PRETTY_FUNCTION__)); | |||
490 | if (SrcTy->isIntegerTy() && DestTy->isPointerTy()) | |||
491 | return Builder.CreateIntToPtr(V, DestTy); | |||
492 | else if (SrcTy->isPointerTy() && DestTy->isIntegerTy()) | |||
493 | return Builder.CreatePtrToInt(V, DestTy); | |||
494 | else | |||
495 | return Builder.CreateBitCast(V, DestTy); | |||
496 | } | |||
497 | ||||
498 | // Erase the instructions in PDIUnrelatedWL as they are unrelated to the | |||
499 | // parameter debug info, from the entry block. | |||
500 | void MergeFunctions::eraseInstsUnrelatedToPDI( | |||
501 | std::vector<Instruction *> &PDIUnrelatedWL) { | |||
502 | ||||
503 | DEBUG(dbgs() << " Erasing instructions (in reverse order of appearance in "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Erasing instructions (in reverse order of appearance in " "entry block) unrelated to parameter debug info from entry " "block: {\n"; } } while (false) | |||
504 | "entry block) unrelated to parameter debug info from entry "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Erasing instructions (in reverse order of appearance in " "entry block) unrelated to parameter debug info from entry " "block: {\n"; } } while (false) | |||
505 | "block: {\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Erasing instructions (in reverse order of appearance in " "entry block) unrelated to parameter debug info from entry " "block: {\n"; } } while (false); | |||
506 | while (!PDIUnrelatedWL.empty()) { | |||
507 | Instruction *I = PDIUnrelatedWL.back(); | |||
508 | DEBUG(dbgs() << " Deleting Instruction: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deleting Instruction: "; } } while (false); | |||
509 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
510 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
511 | I->eraseFromParent(); | |||
512 | PDIUnrelatedWL.pop_back(); | |||
513 | } | |||
514 | DEBUG(dbgs() << " } // Done erasing instructions unrelated to parameter "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " } // Done erasing instructions unrelated to parameter " "debug info from entry block. \n"; } } while (false) | |||
515 | "debug info from entry block. \n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " } // Done erasing instructions unrelated to parameter " "debug info from entry block. \n"; } } while (false); | |||
516 | } | |||
517 | ||||
518 | // Reduce G to its entry block. | |||
519 | void MergeFunctions::eraseTail(Function *G) { | |||
520 | ||||
521 | std::vector<BasicBlock *> WorklistBB; | |||
522 | for (Function::iterator BBI = std::next(G->begin()), BBE = G->end(); | |||
523 | BBI != BBE; ++BBI) { | |||
524 | BBI->dropAllReferences(); | |||
525 | WorklistBB.push_back(&*BBI); | |||
526 | } | |||
527 | while (!WorklistBB.empty()) { | |||
528 | BasicBlock *BB = WorklistBB.back(); | |||
529 | BB->eraseFromParent(); | |||
530 | WorklistBB.pop_back(); | |||
531 | } | |||
532 | } | |||
533 | ||||
534 | // We are interested in the following instructions from the entry block as being | |||
535 | // related to parameter debug info: | |||
536 | // - @llvm.dbg.declare | |||
537 | // - stores from the incoming parameters to locations on the stack-frame | |||
538 | // - allocas that create these locations on the stack-frame | |||
539 | // - @llvm.dbg.value | |||
540 | // - the entry block's terminator | |||
541 | // The rest are unrelated to debug info for the parameters; fill up | |||
542 | // PDIUnrelatedWL with such instructions. | |||
543 | void MergeFunctions::filterInstsUnrelatedToPDI( | |||
544 | BasicBlock *GEntryBlock, std::vector<Instruction *> &PDIUnrelatedWL) { | |||
545 | ||||
546 | std::set<Instruction *> PDIRelated; | |||
547 | for (BasicBlock::iterator BI = GEntryBlock->begin(), BIE = GEntryBlock->end(); | |||
548 | BI != BIE; ++BI) { | |||
549 | if (auto *DVI = dyn_cast<DbgValueInst>(&*BI)) { | |||
550 | DEBUG(dbgs() << " Deciding: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deciding: "; } } while (false ); | |||
551 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
552 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
553 | DILocalVariable *DILocVar = DVI->getVariable(); | |||
554 | if (DILocVar->isParameter()) { | |||
555 | DEBUG(dbgs() << " Include (parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include (parameter): "; } } while (false); | |||
556 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
557 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
558 | PDIRelated.insert(&*BI); | |||
559 | } else { | |||
560 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
561 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
562 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
563 | } | |||
564 | } else if (auto *DDI = dyn_cast<DbgDeclareInst>(&*BI)) { | |||
565 | DEBUG(dbgs() << " Deciding: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deciding: "; } } while (false ); | |||
566 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
567 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
568 | DILocalVariable *DILocVar = DDI->getVariable(); | |||
569 | if (DILocVar->isParameter()) { | |||
570 | DEBUG(dbgs() << " Parameter: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Parameter: "; } } while ( false); | |||
571 | DEBUG(DILocVar->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { DILocVar->print(dbgs()); } } while (false ); | |||
572 | AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress()); | |||
573 | if (AI) { | |||
574 | DEBUG(dbgs() << " Processing alloca users: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Processing alloca users: " ; } } while (false); | |||
575 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
576 | for (User *U : AI->users()) { | |||
577 | if (StoreInst *SI = dyn_cast<StoreInst>(U)) { | |||
578 | if (Value *Arg = SI->getValueOperand()) { | |||
579 | if (dyn_cast<Argument>(Arg)) { | |||
580 | DEBUG(dbgs() << " Include: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include: "; } } while (false ); | |||
581 | DEBUG(AI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { AI->print(dbgs()); } } while (false); | |||
582 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
583 | PDIRelated.insert(AI); | |||
584 | DEBUG(dbgs() << " Include (parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include (parameter): "; } } while (false); | |||
585 | DEBUG(SI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { SI->print(dbgs()); } } while (false); | |||
586 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
587 | PDIRelated.insert(SI); | |||
588 | DEBUG(dbgs() << " Include: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include: "; } } while (false ); | |||
589 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
590 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
591 | PDIRelated.insert(&*BI); | |||
592 | } else { | |||
593 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
594 | DEBUG(SI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { SI->print(dbgs()); } } while (false); | |||
595 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
596 | } | |||
597 | } | |||
598 | } else { | |||
599 | DEBUG(dbgs() << " Defer: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Defer: "; } } while (false ); | |||
600 | DEBUG(U->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { U->print(dbgs()); } } while (false); | |||
601 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
602 | } | |||
603 | } | |||
604 | } else { | |||
605 | DEBUG(dbgs() << " Delete (alloca NULL): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (alloca NULL): "; } } while (false); | |||
606 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
607 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
608 | } | |||
609 | } else { | |||
610 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
611 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
612 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
613 | } | |||
614 | } else if (dyn_cast<TerminatorInst>(BI) == GEntryBlock->getTerminator()) { | |||
615 | DEBUG(dbgs() << " Will Include Terminator: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Will Include Terminator: " ; } } while (false); | |||
616 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
617 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
618 | PDIRelated.insert(&*BI); | |||
619 | } else { | |||
620 | DEBUG(dbgs() << " Defer: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Defer: "; } } while (false ); | |||
621 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
622 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
623 | } | |||
624 | } | |||
625 | DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Report parameter debug info related/related instructions: {\n" ; } } while (false) | |||
626 | << " Report parameter debug info related/related instructions: {\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Report parameter debug info related/related instructions: {\n" ; } } while (false); | |||
627 | for (BasicBlock::iterator BI = GEntryBlock->begin(), BE = GEntryBlock->end(); | |||
628 | BI != BE; ++BI) { | |||
629 | ||||
630 | Instruction *I = &*BI; | |||
631 | if (PDIRelated.find(I) == PDIRelated.end()) { | |||
632 | DEBUG(dbgs() << " !PDIRelated: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " !PDIRelated: "; } } while (false); | |||
633 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
634 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
635 | PDIUnrelatedWL.push_back(I); | |||
636 | } else { | |||
637 | DEBUG(dbgs() << " PDIRelated: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " PDIRelated: "; } } while (false); | |||
638 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
639 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
640 | } | |||
641 | } | |||
642 | DEBUG(dbgs() << " }\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " }\n"; } } while (false); | |||
643 | } | |||
644 | ||||
645 | // Replace G with a simple tail call to bitcast(F). Also (unless | |||
646 | // MergeFunctionsPDI holds) replace direct uses of G with bitcast(F), | |||
647 | // delete G. Under MergeFunctionsPDI, we use G itself for creating | |||
648 | // the thunk as we preserve the debug info (and associated instructions) | |||
649 | // from G's entry block pertaining to G's incoming arguments which are | |||
650 | // passed on as corresponding arguments in the call that G makes to F. | |||
651 | // For better debugability, under MergeFunctionsPDI, we do not modify G's | |||
652 | // call sites to point to F even when within the same translation unit. | |||
653 | void MergeFunctions::writeThunk(Function *F, Function *G) { | |||
654 | if (!G->isInterposable() && !MergeFunctionsPDI) { | |||
655 | // Redirect direct callers of G to F. (See note on MergeFunctionsPDI | |||
656 | // above). | |||
657 | replaceDirectCallers(G, F); | |||
658 | } | |||
659 | ||||
660 | // If G was internal then we may have replaced all uses of G with F. If so, | |||
661 | // stop here and delete G. There's no need for a thunk. (See note on | |||
662 | // MergeFunctionsPDI above). | |||
663 | if (G->hasLocalLinkage() && G->use_empty() && !MergeFunctionsPDI) { | |||
664 | G->eraseFromParent(); | |||
665 | return; | |||
666 | } | |||
667 | ||||
668 | BasicBlock *GEntryBlock = nullptr; | |||
669 | std::vector<Instruction *> PDIUnrelatedWL; | |||
670 | BasicBlock *BB = nullptr; | |||
671 | Function *NewG = nullptr; | |||
672 | if (MergeFunctionsPDI) { | |||
673 | DEBUG(dbgs() << "writeThunk: (MergeFunctionsPDI) Do not create a new "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) Do not create a new " "function as thunk; retain original: " << G->getName () << "()\n"; } } while (false) | |||
674 | "function as thunk; retain original: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) Do not create a new " "function as thunk; retain original: " << G->getName () << "()\n"; } } while (false) | |||
675 | << G->getName() << "()\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) Do not create a new " "function as thunk; retain original: " << G->getName () << "()\n"; } } while (false); | |||
676 | GEntryBlock = &G->getEntryBlock(); | |||
677 | DEBUG(dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related " "debug info for " << G->getName() << "() {\n" ; } } while (false) | |||
678 | "debug info for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related " "debug info for " << G->getName() << "() {\n" ; } } while (false) | |||
679 | << G->getName() << "() {\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related " "debug info for " << G->getName() << "() {\n" ; } } while (false); | |||
680 | filterInstsUnrelatedToPDI(GEntryBlock, PDIUnrelatedWL); | |||
681 | GEntryBlock->getTerminator()->eraseFromParent(); | |||
682 | BB = GEntryBlock; | |||
683 | } else { | |||
684 | NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "", | |||
685 | G->getParent()); | |||
686 | BB = BasicBlock::Create(F->getContext(), "", NewG); | |||
687 | } | |||
688 | ||||
689 | IRBuilder<> Builder(BB); | |||
690 | Function *H = MergeFunctionsPDI ? G : NewG; | |||
691 | SmallVector<Value *, 16> Args; | |||
692 | unsigned i = 0; | |||
693 | FunctionType *FFTy = F->getFunctionType(); | |||
694 | for (Argument & AI : H->args()) { | |||
695 | Args.push_back(createCast(Builder, &AI, FFTy->getParamType(i))); | |||
696 | ++i; | |||
697 | } | |||
698 | ||||
699 | CallInst *CI = Builder.CreateCall(F, Args); | |||
700 | ReturnInst *RI = nullptr; | |||
701 | CI->setTailCall(); | |||
702 | CI->setCallingConv(F->getCallingConv()); | |||
703 | CI->setAttributes(F->getAttributes()); | |||
704 | if (H->getReturnType()->isVoidTy()) { | |||
705 | RI = Builder.CreateRetVoid(); | |||
706 | } else { | |||
707 | RI = Builder.CreateRet(createCast(Builder, CI, H->getReturnType())); | |||
708 | } | |||
709 | ||||
710 | if (MergeFunctionsPDI) { | |||
711 | DISubprogram *DIS = G->getSubprogram(); | |||
712 | if (DIS) { | |||
713 | DebugLoc CIDbgLoc = DebugLoc::get(DIS->getScopeLine(), 0, DIS); | |||
714 | DebugLoc RIDbgLoc = DebugLoc::get(DIS->getScopeLine(), 0, DIS); | |||
715 | CI->setDebugLoc(CIDbgLoc); | |||
716 | RI->setDebugLoc(RIDbgLoc); | |||
717 | } else { | |||
718 | DEBUG(dbgs() << "writeThunk: (MergeFunctionsPDI) No DISubprogram for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) No DISubprogram for " << G->getName() << "()\n"; } } while (false) | |||
719 | << G->getName() << "()\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) No DISubprogram for " << G->getName() << "()\n"; } } while (false); | |||
720 | } | |||
721 | eraseTail(G); | |||
722 | eraseInstsUnrelatedToPDI(PDIUnrelatedWL); | |||
723 | DEBUG(dbgs() << "} // End of parameter related debug info filtering for: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "} // End of parameter related debug info filtering for: " << G->getName() << "()\n"; } } while (false) | |||
724 | << G->getName() << "()\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "} // End of parameter related debug info filtering for: " << G->getName() << "()\n"; } } while (false); | |||
725 | } else { | |||
726 | NewG->copyAttributesFrom(G); | |||
| ||||
727 | NewG->takeName(G); | |||
728 | removeUsers(G); | |||
729 | G->replaceAllUsesWith(NewG); | |||
730 | G->eraseFromParent(); | |||
731 | } | |||
732 | ||||
733 | DEBUG(dbgs() << "writeThunk: " << H->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: " << H-> getName() << '\n'; } } while (false); | |||
734 | ++NumThunksWritten; | |||
735 | } | |||
736 | ||||
737 | // Replace G with an alias to F and delete G. | |||
738 | void MergeFunctions::writeAlias(Function *F, Function *G) { | |||
739 | auto *GA = GlobalAlias::create(G->getLinkage(), "", F); | |||
740 | F->setAlignment(std::max(F->getAlignment(), G->getAlignment())); | |||
741 | GA->takeName(G); | |||
742 | GA->setVisibility(G->getVisibility()); | |||
743 | removeUsers(G); | |||
744 | G->replaceAllUsesWith(GA); | |||
745 | G->eraseFromParent(); | |||
746 | ||||
747 | DEBUG(dbgs() << "writeAlias: " << GA->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeAlias: " << GA-> getName() << '\n'; } } while (false); | |||
748 | ++NumAliasesWritten; | |||
749 | } | |||
750 | ||||
751 | // Merge two equivalent functions. Upon completion, Function G is deleted. | |||
752 | void MergeFunctions::mergeTwoFunctions(Function *F, Function *G) { | |||
753 | if (F->isInterposable()) { | |||
754 | assert(G->isInterposable())((G->isInterposable()) ? static_cast<void> (0) : __assert_fail ("G->isInterposable()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 754, __PRETTY_FUNCTION__)); | |||
755 | ||||
756 | // Make them both thunks to the same internal function. | |||
757 | Function *H = Function::Create(F->getFunctionType(), F->getLinkage(), "", | |||
758 | F->getParent()); | |||
759 | H->copyAttributesFrom(F); | |||
760 | H->takeName(F); | |||
761 | removeUsers(F); | |||
762 | F->replaceAllUsesWith(H); | |||
763 | ||||
764 | unsigned MaxAlignment = std::max(G->getAlignment(), H->getAlignment()); | |||
765 | ||||
766 | if (HasGlobalAliases) { | |||
767 | writeAlias(F, G); | |||
768 | writeAlias(F, H); | |||
769 | } else { | |||
770 | writeThunk(F, G); | |||
771 | writeThunk(F, H); | |||
772 | } | |||
773 | ||||
774 | F->setAlignment(MaxAlignment); | |||
775 | F->setLinkage(GlobalValue::PrivateLinkage); | |||
776 | ++NumDoubleWeak; | |||
777 | } else { | |||
778 | writeThunkOrAlias(F, G); | |||
779 | } | |||
780 | ||||
781 | ++NumFunctionsMerged; | |||
782 | } | |||
783 | ||||
784 | /// Replace function F by function G. | |||
785 | void MergeFunctions::replaceFunctionInTree(const FunctionNode &FN, | |||
786 | Function *G) { | |||
787 | Function *F = FN.getFunc(); | |||
788 | assert(FunctionComparator(F, G, &GlobalNumbers).compare() == 0 &&((FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && "The two functions must be equal") ? static_cast< void> (0) : __assert_fail ("FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && \"The two functions must be equal\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 789, __PRETTY_FUNCTION__)) | |||
789 | "The two functions must be equal")((FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && "The two functions must be equal") ? static_cast< void> (0) : __assert_fail ("FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && \"The two functions must be equal\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 789, __PRETTY_FUNCTION__)); | |||
790 | ||||
791 | auto I = FNodesInTree.find(F); | |||
792 | assert(I != FNodesInTree.end() && "F should be in FNodesInTree")((I != FNodesInTree.end() && "F should be in FNodesInTree" ) ? static_cast<void> (0) : __assert_fail ("I != FNodesInTree.end() && \"F should be in FNodesInTree\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 792, __PRETTY_FUNCTION__)); | |||
793 | assert(FNodesInTree.count(G) == 0 && "FNodesInTree should not contain G")((FNodesInTree.count(G) == 0 && "FNodesInTree should not contain G" ) ? static_cast<void> (0) : __assert_fail ("FNodesInTree.count(G) == 0 && \"FNodesInTree should not contain G\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 793, __PRETTY_FUNCTION__)); | |||
794 | ||||
795 | FnTreeType::iterator IterToFNInFnTree = I->second; | |||
796 | assert(&(*IterToFNInFnTree) == &FN && "F should map to FN in FNodesInTree.")((&(*IterToFNInFnTree) == &FN && "F should map to FN in FNodesInTree." ) ? static_cast<void> (0) : __assert_fail ("&(*IterToFNInFnTree) == &FN && \"F should map to FN in FNodesInTree.\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 796, __PRETTY_FUNCTION__)); | |||
797 | // Remove F -> FN and insert G -> FN | |||
798 | FNodesInTree.erase(I); | |||
799 | FNodesInTree.insert({G, IterToFNInFnTree}); | |||
800 | // Replace F with G in FN, which is stored inside the FnTree. | |||
801 | FN.replaceBy(G); | |||
802 | } | |||
803 | ||||
804 | // Insert a ComparableFunction into the FnTree, or merge it away if equal to one | |||
805 | // that was already inserted. | |||
806 | bool MergeFunctions::insert(Function *NewFunction) { | |||
807 | std::pair<FnTreeType::iterator, bool> Result = | |||
808 | FnTree.insert(FunctionNode(NewFunction)); | |||
809 | ||||
810 | if (Result.second) { | |||
811 | assert(FNodesInTree.count(NewFunction) == 0)((FNodesInTree.count(NewFunction) == 0) ? static_cast<void > (0) : __assert_fail ("FNodesInTree.count(NewFunction) == 0" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 811, __PRETTY_FUNCTION__)); | |||
812 | FNodesInTree.insert({NewFunction, Result.first}); | |||
813 | DEBUG(dbgs() << "Inserting as unique: " << NewFunction->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "Inserting as unique: " << NewFunction->getName() << '\n'; } } while (false); | |||
814 | return false; | |||
815 | } | |||
816 | ||||
817 | const FunctionNode &OldF = *Result.first; | |||
818 | ||||
819 | // Don't merge tiny functions, since it can just end up making the function | |||
820 | // larger. | |||
821 | // FIXME: Should still merge them if they are unnamed_addr and produce an | |||
822 | // alias. | |||
823 | if (NewFunction->size() == 1) { | |||
824 | if (NewFunction->front().size() <= 2) { | |||
825 | DEBUG(dbgs() << NewFunction->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << NewFunction->getName() << " is to small to bother merging\n"; } } while (false) | |||
826 | << " is to small to bother merging\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << NewFunction->getName() << " is to small to bother merging\n"; } } while (false); | |||
827 | return false; | |||
828 | } | |||
829 | } | |||
830 | ||||
831 | // Impose a total order (by name) on the replacement of functions. This is | |||
832 | // important when operating on more than one module independently to prevent | |||
833 | // cycles of thunks calling each other when the modules are linked together. | |||
834 | // | |||
835 | // First of all, we process strong functions before weak functions. | |||
836 | if ((OldF.getFunc()->isInterposable() && !NewFunction->isInterposable()) || | |||
837 | (OldF.getFunc()->isInterposable() == NewFunction->isInterposable() && | |||
838 | OldF.getFunc()->getName() > NewFunction->getName())) { | |||
839 | // Swap the two functions. | |||
840 | Function *F = OldF.getFunc(); | |||
841 | replaceFunctionInTree(*Result.first, NewFunction); | |||
842 | NewFunction = F; | |||
843 | assert(OldF.getFunc() != F && "Must have swapped the functions.")((OldF.getFunc() != F && "Must have swapped the functions." ) ? static_cast<void> (0) : __assert_fail ("OldF.getFunc() != F && \"Must have swapped the functions.\"" , "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn306458/lib/Transforms/IPO/MergeFunctions.cpp" , 843, __PRETTY_FUNCTION__)); | |||
844 | } | |||
845 | ||||
846 | DEBUG(dbgs() << " " << OldF.getFunc()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " " << OldF.getFunc() ->getName() << " == " << NewFunction->getName () << '\n'; } } while (false) | |||
847 | << " == " << NewFunction->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " " << OldF.getFunc() ->getName() << " == " << NewFunction->getName () << '\n'; } } while (false); | |||
848 | ||||
849 | Function *DeleteF = NewFunction; | |||
850 | mergeTwoFunctions(OldF.getFunc(), DeleteF); | |||
851 | return true; | |||
852 | } | |||
853 | ||||
854 | // Remove a function from FnTree. If it was already in FnTree, add | |||
855 | // it to Deferred so that we'll look at it in the next round. | |||
856 | void MergeFunctions::remove(Function *F) { | |||
857 | auto I = FNodesInTree.find(F); | |||
858 | if (I != FNodesInTree.end()) { | |||
859 | DEBUG(dbgs() << "Deferred " << F->getName()<< ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "Deferred " << F->getName ()<< ".\n"; } } while (false); | |||
860 | FnTree.erase(I->second); | |||
861 | // I->second has been invalidated, remove it from the FNodesInTree map to | |||
862 | // preserve the invariant. | |||
863 | FNodesInTree.erase(I); | |||
864 | Deferred.emplace_back(F); | |||
865 | } | |||
866 | } | |||
867 | ||||
868 | // For each instruction used by the value, remove() the function that contains | |||
869 | // the instruction. This should happen right before a call to RAUW. | |||
870 | void MergeFunctions::removeUsers(Value *V) { | |||
871 | std::vector<Value *> Worklist; | |||
872 | Worklist.push_back(V); | |||
873 | SmallSet<Value*, 8> Visited; | |||
874 | Visited.insert(V); | |||
875 | while (!Worklist.empty()) { | |||
876 | Value *V = Worklist.back(); | |||
877 | Worklist.pop_back(); | |||
878 | ||||
879 | for (User *U : V->users()) { | |||
880 | if (Instruction *I = dyn_cast<Instruction>(U)) { | |||
881 | remove(I->getParent()->getParent()); | |||
882 | } else if (isa<GlobalValue>(U)) { | |||
883 | // do nothing | |||
884 | } else if (Constant *C = dyn_cast<Constant>(U)) { | |||
885 | for (User *UU : C->users()) { | |||
886 | if (!Visited.insert(UU).second) | |||
887 | Worklist.push_back(UU); | |||
888 | } | |||
889 | } | |||
890 | } | |||
891 | } | |||
892 | } |