File: | lib/Transforms/IPO/MergeFunctions.cpp |
Warning: | line 709, column 23 Called C++ object pointer is null |
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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/ArrayRef.h" | |||
93 | #include "llvm/ADT/SmallSet.h" | |||
94 | #include "llvm/ADT/SmallVector.h" | |||
95 | #include "llvm/ADT/Statistic.h" | |||
96 | #include "llvm/IR/Argument.h" | |||
97 | #include "llvm/IR/Attributes.h" | |||
98 | #include "llvm/IR/BasicBlock.h" | |||
99 | #include "llvm/IR/CallSite.h" | |||
100 | #include "llvm/IR/Constant.h" | |||
101 | #include "llvm/IR/Constants.h" | |||
102 | #include "llvm/IR/DebugInfoMetadata.h" | |||
103 | #include "llvm/IR/DebugLoc.h" | |||
104 | #include "llvm/IR/DerivedTypes.h" | |||
105 | #include "llvm/IR/Function.h" | |||
106 | #include "llvm/IR/GlobalValue.h" | |||
107 | #include "llvm/IR/IRBuilder.h" | |||
108 | #include "llvm/IR/InstrTypes.h" | |||
109 | #include "llvm/IR/Instruction.h" | |||
110 | #include "llvm/IR/Instructions.h" | |||
111 | #include "llvm/IR/IntrinsicInst.h" | |||
112 | #include "llvm/IR/Module.h" | |||
113 | #include "llvm/IR/Type.h" | |||
114 | #include "llvm/IR/Use.h" | |||
115 | #include "llvm/IR/User.h" | |||
116 | #include "llvm/IR/Value.h" | |||
117 | #include "llvm/IR/ValueHandle.h" | |||
118 | #include "llvm/IR/ValueMap.h" | |||
119 | #include "llvm/Pass.h" | |||
120 | #include "llvm/Support/Casting.h" | |||
121 | #include "llvm/Support/CommandLine.h" | |||
122 | #include "llvm/Support/Debug.h" | |||
123 | #include "llvm/Support/raw_ostream.h" | |||
124 | #include "llvm/Transforms/IPO.h" | |||
125 | #include "llvm/Transforms/Utils/FunctionComparator.h" | |||
126 | #include <algorithm> | |||
127 | #include <cassert> | |||
128 | #include <iterator> | |||
129 | #include <set> | |||
130 | #include <utility> | |||
131 | #include <vector> | |||
132 | ||||
133 | using namespace llvm; | |||
134 | ||||
135 | #define DEBUG_TYPE"mergefunc" "mergefunc" | |||
136 | ||||
137 | STATISTIC(NumFunctionsMerged, "Number of functions merged")static llvm::Statistic NumFunctionsMerged = {"mergefunc", "NumFunctionsMerged" , "Number of functions merged", {0}, {false}}; | |||
138 | STATISTIC(NumThunksWritten, "Number of thunks generated")static llvm::Statistic NumThunksWritten = {"mergefunc", "NumThunksWritten" , "Number of thunks generated", {0}, {false}}; | |||
139 | STATISTIC(NumDoubleWeak, "Number of new functions created")static llvm::Statistic NumDoubleWeak = {"mergefunc", "NumDoubleWeak" , "Number of new functions created", {0}, {false}}; | |||
140 | ||||
141 | static cl::opt<unsigned> NumFunctionsForSanityCheck( | |||
142 | "mergefunc-sanity", | |||
143 | cl::desc("How many functions in module could be used for " | |||
144 | "MergeFunctions pass sanity check. " | |||
145 | "'0' disables this check. Works only with '-debug' key."), | |||
146 | cl::init(0), cl::Hidden); | |||
147 | ||||
148 | // Under option -mergefunc-preserve-debug-info we: | |||
149 | // - Do not create a new function for a thunk. | |||
150 | // - Retain the debug info for a thunk's parameters (and associated | |||
151 | // instructions for the debug info) from the entry block. | |||
152 | // Note: -debug will display the algorithm at work. | |||
153 | // - Create debug-info for the call (to the shared implementation) made by | |||
154 | // a thunk and its return value. | |||
155 | // - Erase the rest of the function, retaining the (minimally sized) entry | |||
156 | // block to create a thunk. | |||
157 | // - Preserve a thunk's call site to point to the thunk even when both occur | |||
158 | // within the same translation unit, to aid debugability. Note that this | |||
159 | // behaviour differs from the underlying -mergefunc implementation which | |||
160 | // modifies the thunk's call site to point to the shared implementation | |||
161 | // when both occur within the same translation unit. | |||
162 | static cl::opt<bool> | |||
163 | MergeFunctionsPDI("mergefunc-preserve-debug-info", cl::Hidden, | |||
164 | cl::init(false), | |||
165 | cl::desc("Preserve debug info in thunk when mergefunc " | |||
166 | "transformations are made.")); | |||
167 | ||||
168 | namespace { | |||
169 | ||||
170 | class FunctionNode { | |||
171 | mutable AssertingVH<Function> F; | |||
172 | FunctionComparator::FunctionHash Hash; | |||
173 | ||||
174 | public: | |||
175 | // Note the hash is recalculated potentially multiple times, but it is cheap. | |||
176 | FunctionNode(Function *F) | |||
177 | : F(F), Hash(FunctionComparator::functionHash(*F)) {} | |||
178 | ||||
179 | Function *getFunc() const { return F; } | |||
180 | FunctionComparator::FunctionHash getHash() const { return Hash; } | |||
181 | ||||
182 | /// Replace the reference to the function F by the function G, assuming their | |||
183 | /// implementations are equal. | |||
184 | void replaceBy(Function *G) const { | |||
185 | F = G; | |||
186 | } | |||
187 | ||||
188 | void release() { F = nullptr; } | |||
189 | }; | |||
190 | ||||
191 | /// MergeFunctions finds functions which will generate identical machine code, | |||
192 | /// by considering all pointer types to be equivalent. Once identified, | |||
193 | /// MergeFunctions will fold them by replacing a call to one to a call to a | |||
194 | /// bitcast of the other. | |||
195 | class MergeFunctions : public ModulePass { | |||
196 | public: | |||
197 | static char ID; | |||
198 | ||||
199 | MergeFunctions() | |||
200 | : ModulePass(ID), FnTree(FunctionNodeCmp(&GlobalNumbers)) { | |||
201 | initializeMergeFunctionsPass(*PassRegistry::getPassRegistry()); | |||
202 | } | |||
203 | ||||
204 | bool runOnModule(Module &M) override; | |||
205 | ||||
206 | private: | |||
207 | // The function comparison operator is provided here so that FunctionNodes do | |||
208 | // not need to become larger with another pointer. | |||
209 | class FunctionNodeCmp { | |||
210 | GlobalNumberState* GlobalNumbers; | |||
211 | ||||
212 | public: | |||
213 | FunctionNodeCmp(GlobalNumberState* GN) : GlobalNumbers(GN) {} | |||
214 | ||||
215 | bool operator()(const FunctionNode &LHS, const FunctionNode &RHS) const { | |||
216 | // Order first by hashes, then full function comparison. | |||
217 | if (LHS.getHash() != RHS.getHash()) | |||
218 | return LHS.getHash() < RHS.getHash(); | |||
219 | FunctionComparator FCmp(LHS.getFunc(), RHS.getFunc(), GlobalNumbers); | |||
220 | return FCmp.compare() == -1; | |||
221 | } | |||
222 | }; | |||
223 | using FnTreeType = std::set<FunctionNode, FunctionNodeCmp>; | |||
224 | ||||
225 | GlobalNumberState GlobalNumbers; | |||
226 | ||||
227 | /// A work queue of functions that may have been modified and should be | |||
228 | /// analyzed again. | |||
229 | std::vector<WeakTrackingVH> Deferred; | |||
230 | ||||
231 | #ifndef NDEBUG | |||
232 | /// Checks the rules of order relation introduced among functions set. | |||
233 | /// Returns true, if sanity check has been passed, and false if failed. | |||
234 | bool doSanityCheck(std::vector<WeakTrackingVH> &Worklist); | |||
235 | #endif | |||
236 | ||||
237 | /// Insert a ComparableFunction into the FnTree, or merge it away if it's | |||
238 | /// equal to one that's already present. | |||
239 | bool insert(Function *NewFunction); | |||
240 | ||||
241 | /// Remove a Function from the FnTree and queue it up for a second sweep of | |||
242 | /// analysis. | |||
243 | void remove(Function *F); | |||
244 | ||||
245 | /// Find the functions that use this Value and remove them from FnTree and | |||
246 | /// queue the functions. | |||
247 | void removeUsers(Value *V); | |||
248 | ||||
249 | /// Replace all direct calls of Old with calls of New. Will bitcast New if | |||
250 | /// necessary to make types match. | |||
251 | void replaceDirectCallers(Function *Old, Function *New); | |||
252 | ||||
253 | /// Merge two equivalent functions. Upon completion, G may be deleted, or may | |||
254 | /// be converted into a thunk. In either case, it should never be visited | |||
255 | /// again. | |||
256 | void mergeTwoFunctions(Function *F, Function *G); | |||
257 | ||||
258 | /// Fill PDIUnrelatedWL with instructions from the entry block that are | |||
259 | /// unrelated to parameter related debug info. | |||
260 | void filterInstsUnrelatedToPDI(BasicBlock *GEntryBlock, | |||
261 | std::vector<Instruction *> &PDIUnrelatedWL); | |||
262 | ||||
263 | /// Erase the rest of the CFG (i.e. barring the entry block). | |||
264 | void eraseTail(Function *G); | |||
265 | ||||
266 | /// Erase the instructions in PDIUnrelatedWL as they are unrelated to the | |||
267 | /// parameter debug info, from the entry block. | |||
268 | void eraseInstsUnrelatedToPDI(std::vector<Instruction *> &PDIUnrelatedWL); | |||
269 | ||||
270 | /// Replace G with a simple tail call to bitcast(F). Also (unless | |||
271 | /// MergeFunctionsPDI holds) replace direct uses of G with bitcast(F), | |||
272 | /// delete G. | |||
273 | void writeThunk(Function *F, Function *G); | |||
274 | ||||
275 | /// Replace function F with function G in the function tree. | |||
276 | void replaceFunctionInTree(const FunctionNode &FN, Function *G); | |||
277 | ||||
278 | /// The set of all distinct functions. Use the insert() and remove() methods | |||
279 | /// to modify it. The map allows efficient lookup and deferring of Functions. | |||
280 | FnTreeType FnTree; | |||
281 | ||||
282 | // Map functions to the iterators of the FunctionNode which contains them | |||
283 | // in the FnTree. This must be updated carefully whenever the FnTree is | |||
284 | // modified, i.e. in insert(), remove(), and replaceFunctionInTree(), to avoid | |||
285 | // dangling iterators into FnTree. The invariant that preserves this is that | |||
286 | // there is exactly one mapping F -> FN for each FunctionNode FN in FnTree. | |||
287 | ValueMap<Function*, FnTreeType::iterator> FNodesInTree; | |||
288 | }; | |||
289 | ||||
290 | } // end anonymous namespace | |||
291 | ||||
292 | char MergeFunctions::ID = 0; | |||
293 | ||||
294 | 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)); } | |||
295 | ||||
296 | ModulePass *llvm::createMergeFunctionsPass() { | |||
297 | return new MergeFunctions(); | |||
298 | } | |||
299 | ||||
300 | #ifndef NDEBUG | |||
301 | bool MergeFunctions::doSanityCheck(std::vector<WeakTrackingVH> &Worklist) { | |||
302 | if (const unsigned Max = NumFunctionsForSanityCheck) { | |||
303 | unsigned TripleNumber = 0; | |||
304 | bool Valid = true; | |||
305 | ||||
306 | dbgs() << "MERGEFUNC-SANITY: Started for first " << Max << " functions.\n"; | |||
307 | ||||
308 | unsigned i = 0; | |||
309 | for (std::vector<WeakTrackingVH>::iterator I = Worklist.begin(), | |||
310 | E = Worklist.end(); | |||
311 | I != E && i < Max; ++I, ++i) { | |||
312 | unsigned j = i; | |||
313 | for (std::vector<WeakTrackingVH>::iterator J = I; J != E && j < Max; | |||
314 | ++J, ++j) { | |||
315 | Function *F1 = cast<Function>(*I); | |||
316 | Function *F2 = cast<Function>(*J); | |||
317 | int Res1 = FunctionComparator(F1, F2, &GlobalNumbers).compare(); | |||
318 | int Res2 = FunctionComparator(F2, F1, &GlobalNumbers).compare(); | |||
319 | ||||
320 | // If F1 <= F2, then F2 >= F1, otherwise report failure. | |||
321 | if (Res1 != -Res2) { | |||
322 | dbgs() << "MERGEFUNC-SANITY: Non-symmetric; triple: " << TripleNumber | |||
323 | << "\n"; | |||
324 | dbgs() << *F1 << '\n' << *F2 << '\n'; | |||
325 | Valid = false; | |||
326 | } | |||
327 | ||||
328 | if (Res1 == 0) | |||
329 | continue; | |||
330 | ||||
331 | unsigned k = j; | |||
332 | for (std::vector<WeakTrackingVH>::iterator K = J; K != E && k < Max; | |||
333 | ++k, ++K, ++TripleNumber) { | |||
334 | if (K == J) | |||
335 | continue; | |||
336 | ||||
337 | Function *F3 = cast<Function>(*K); | |||
338 | int Res3 = FunctionComparator(F1, F3, &GlobalNumbers).compare(); | |||
339 | int Res4 = FunctionComparator(F2, F3, &GlobalNumbers).compare(); | |||
340 | ||||
341 | bool Transitive = true; | |||
342 | ||||
343 | if (Res1 != 0 && Res1 == Res4) { | |||
344 | // F1 > F2, F2 > F3 => F1 > F3 | |||
345 | Transitive = Res3 == Res1; | |||
346 | } else if (Res3 != 0 && Res3 == -Res4) { | |||
347 | // F1 > F3, F3 > F2 => F1 > F2 | |||
348 | Transitive = Res3 == Res1; | |||
349 | } else if (Res4 != 0 && -Res3 == Res4) { | |||
350 | // F2 > F3, F3 > F1 => F2 > F1 | |||
351 | Transitive = Res4 == -Res1; | |||
352 | } | |||
353 | ||||
354 | if (!Transitive) { | |||
355 | dbgs() << "MERGEFUNC-SANITY: Non-transitive; triple: " | |||
356 | << TripleNumber << "\n"; | |||
357 | dbgs() << "Res1, Res3, Res4: " << Res1 << ", " << Res3 << ", " | |||
358 | << Res4 << "\n"; | |||
359 | dbgs() << *F1 << '\n' << *F2 << '\n' << *F3 << '\n'; | |||
360 | Valid = false; | |||
361 | } | |||
362 | } | |||
363 | } | |||
364 | } | |||
365 | ||||
366 | dbgs() << "MERGEFUNC-SANITY: " << (Valid ? "Passed." : "Failed.") << "\n"; | |||
367 | return Valid; | |||
368 | } | |||
369 | return true; | |||
370 | } | |||
371 | #endif | |||
372 | ||||
373 | bool MergeFunctions::runOnModule(Module &M) { | |||
374 | if (skipModule(M)) | |||
| ||||
375 | return false; | |||
376 | ||||
377 | bool Changed = false; | |||
378 | ||||
379 | // All functions in the module, ordered by hash. Functions with a unique | |||
380 | // hash value are easily eliminated. | |||
381 | std::vector<std::pair<FunctionComparator::FunctionHash, Function *>> | |||
382 | HashedFuncs; | |||
383 | for (Function &Func : M) { | |||
384 | if (!Func.isDeclaration() && !Func.hasAvailableExternallyLinkage()) { | |||
385 | HashedFuncs.push_back({FunctionComparator::functionHash(Func), &Func}); | |||
386 | } | |||
387 | } | |||
388 | ||||
389 | std::stable_sort( | |||
390 | HashedFuncs.begin(), HashedFuncs.end(), | |||
391 | [](const std::pair<FunctionComparator::FunctionHash, Function *> &a, | |||
392 | const std::pair<FunctionComparator::FunctionHash, Function *> &b) { | |||
393 | return a.first < b.first; | |||
394 | }); | |||
395 | ||||
396 | auto S = HashedFuncs.begin(); | |||
397 | for (auto I = HashedFuncs.begin(), IE = HashedFuncs.end(); I != IE; ++I) { | |||
398 | // If the hash value matches the previous value or the next one, we must | |||
399 | // consider merging it. Otherwise it is dropped and never considered again. | |||
400 | if ((I != S && std::prev(I)->first == I->first) || | |||
401 | (std::next(I) != IE && std::next(I)->first == I->first) ) { | |||
402 | Deferred.push_back(WeakTrackingVH(I->second)); | |||
403 | } | |||
404 | } | |||
405 | ||||
406 | do { | |||
407 | std::vector<WeakTrackingVH> Worklist; | |||
408 | Deferred.swap(Worklist); | |||
409 | ||||
410 | DEBUG(doSanityCheck(Worklist))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { doSanityCheck(Worklist); } } while (false); | |||
411 | ||||
412 | DEBUG(dbgs() << "size of module: " << M.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of module: " << M .size() << '\n'; } } while (false); | |||
413 | DEBUG(dbgs() << "size of worklist: " << Worklist.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of worklist: " << Worklist.size() << '\n'; } } while (false); | |||
414 | ||||
415 | // Insert functions and merge them. | |||
416 | for (WeakTrackingVH &I : Worklist) { | |||
417 | if (!I) | |||
418 | continue; | |||
419 | Function *F = cast<Function>(I); | |||
420 | if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage()) { | |||
421 | Changed |= insert(F); | |||
422 | } | |||
423 | } | |||
424 | DEBUG(dbgs() << "size of FnTree: " << FnTree.size() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "size of FnTree: " << FnTree .size() << '\n'; } } while (false); | |||
425 | } while (!Deferred.empty()); | |||
426 | ||||
427 | FnTree.clear(); | |||
428 | GlobalNumbers.clear(); | |||
429 | ||||
430 | return Changed; | |||
431 | } | |||
432 | ||||
433 | // Replace direct callers of Old with New. | |||
434 | void MergeFunctions::replaceDirectCallers(Function *Old, Function *New) { | |||
435 | Constant *BitcastNew = ConstantExpr::getBitCast(New, Old->getType()); | |||
436 | for (auto UI = Old->use_begin(), UE = Old->use_end(); UI != UE;) { | |||
437 | Use *U = &*UI; | |||
438 | ++UI; | |||
439 | CallSite CS(U->getUser()); | |||
440 | if (CS && CS.isCallee(U)) { | |||
441 | // Transfer the called function's attributes to the call site. Due to the | |||
442 | // bitcast we will 'lose' ABI changing attributes because the 'called | |||
443 | // function' is no longer a Function* but the bitcast. Code that looks up | |||
444 | // the attributes from the called function will fail. | |||
445 | ||||
446 | // FIXME: This is not actually true, at least not anymore. The callsite | |||
447 | // will always have the same ABI affecting attributes as the callee, | |||
448 | // because otherwise the original input has UB. Note that Old and New | |||
449 | // always have matching ABI, so no attributes need to be changed. | |||
450 | // Transferring other attributes may help other optimizations, but that | |||
451 | // should be done uniformly and not in this ad-hoc way. | |||
452 | auto &Context = New->getContext(); | |||
453 | auto NewPAL = New->getAttributes(); | |||
454 | SmallVector<AttributeSet, 4> NewArgAttrs; | |||
455 | for (unsigned argIdx = 0; argIdx < CS.arg_size(); argIdx++) | |||
456 | NewArgAttrs.push_back(NewPAL.getParamAttributes(argIdx)); | |||
457 | // Don't transfer attributes from the function to the callee. Function | |||
458 | // attributes typically aren't relevant to the calling convention or ABI. | |||
459 | CS.setAttributes(AttributeList::get(Context, /*FnAttrs=*/AttributeSet(), | |||
460 | NewPAL.getRetAttributes(), | |||
461 | NewArgAttrs)); | |||
462 | ||||
463 | remove(CS.getInstruction()->getParent()->getParent()); | |||
464 | U->set(BitcastNew); | |||
465 | } | |||
466 | } | |||
467 | } | |||
468 | ||||
469 | // Helper for writeThunk, | |||
470 | // Selects proper bitcast operation, | |||
471 | // but a bit simpler then CastInst::getCastOpcode. | |||
472 | static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) { | |||
473 | Type *SrcTy = V->getType(); | |||
474 | if (SrcTy->isStructTy()) { | |||
475 | assert(DestTy->isStructTy())(static_cast <bool> (DestTy->isStructTy()) ? void (0 ) : __assert_fail ("DestTy->isStructTy()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 475, __extension__ __PRETTY_FUNCTION__)); | |||
476 | assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements())(static_cast <bool> (SrcTy->getStructNumElements() == DestTy->getStructNumElements()) ? void (0) : __assert_fail ("SrcTy->getStructNumElements() == DestTy->getStructNumElements()" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 476, __extension__ __PRETTY_FUNCTION__)); | |||
477 | Value *Result = UndefValue::get(DestTy); | |||
478 | for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) { | |||
479 | Value *Element = createCast( | |||
480 | Builder, Builder.CreateExtractValue(V, makeArrayRef(I)), | |||
481 | DestTy->getStructElementType(I)); | |||
482 | ||||
483 | Result = | |||
484 | Builder.CreateInsertValue(Result, Element, makeArrayRef(I)); | |||
485 | } | |||
486 | return Result; | |||
487 | } | |||
488 | assert(!DestTy->isStructTy())(static_cast <bool> (!DestTy->isStructTy()) ? void ( 0) : __assert_fail ("!DestTy->isStructTy()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 488, __extension__ __PRETTY_FUNCTION__)); | |||
489 | if (SrcTy->isIntegerTy() && DestTy->isPointerTy()) | |||
490 | return Builder.CreateIntToPtr(V, DestTy); | |||
491 | else if (SrcTy->isPointerTy() && DestTy->isIntegerTy()) | |||
492 | return Builder.CreatePtrToInt(V, DestTy); | |||
493 | else | |||
494 | return Builder.CreateBitCast(V, DestTy); | |||
495 | } | |||
496 | ||||
497 | // Erase the instructions in PDIUnrelatedWL as they are unrelated to the | |||
498 | // parameter debug info, from the entry block. | |||
499 | void MergeFunctions::eraseInstsUnrelatedToPDI( | |||
500 | std::vector<Instruction *> &PDIUnrelatedWL) { | |||
501 | 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) | |||
502 | "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) | |||
503 | "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); | |||
504 | while (!PDIUnrelatedWL.empty()) { | |||
505 | Instruction *I = PDIUnrelatedWL.back(); | |||
506 | DEBUG(dbgs() << " Deleting Instruction: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deleting Instruction: "; } } while (false); | |||
507 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
508 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
509 | I->eraseFromParent(); | |||
510 | PDIUnrelatedWL.pop_back(); | |||
511 | } | |||
512 | 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) | |||
513 | "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); | |||
514 | } | |||
515 | ||||
516 | // Reduce G to its entry block. | |||
517 | void MergeFunctions::eraseTail(Function *G) { | |||
518 | std::vector<BasicBlock *> WorklistBB; | |||
519 | for (Function::iterator BBI = std::next(G->begin()), BBE = G->end(); | |||
520 | BBI != BBE; ++BBI) { | |||
521 | BBI->dropAllReferences(); | |||
522 | WorklistBB.push_back(&*BBI); | |||
523 | } | |||
524 | while (!WorklistBB.empty()) { | |||
525 | BasicBlock *BB = WorklistBB.back(); | |||
526 | BB->eraseFromParent(); | |||
527 | WorklistBB.pop_back(); | |||
528 | } | |||
529 | } | |||
530 | ||||
531 | // We are interested in the following instructions from the entry block as being | |||
532 | // related to parameter debug info: | |||
533 | // - @llvm.dbg.declare | |||
534 | // - stores from the incoming parameters to locations on the stack-frame | |||
535 | // - allocas that create these locations on the stack-frame | |||
536 | // - @llvm.dbg.value | |||
537 | // - the entry block's terminator | |||
538 | // The rest are unrelated to debug info for the parameters; fill up | |||
539 | // PDIUnrelatedWL with such instructions. | |||
540 | void MergeFunctions::filterInstsUnrelatedToPDI( | |||
541 | BasicBlock *GEntryBlock, std::vector<Instruction *> &PDIUnrelatedWL) { | |||
542 | std::set<Instruction *> PDIRelated; | |||
543 | for (BasicBlock::iterator BI = GEntryBlock->begin(), BIE = GEntryBlock->end(); | |||
544 | BI != BIE; ++BI) { | |||
545 | if (auto *DVI = dyn_cast<DbgValueInst>(&*BI)) { | |||
546 | DEBUG(dbgs() << " Deciding: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deciding: "; } } while (false ); | |||
547 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
548 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
549 | DILocalVariable *DILocVar = DVI->getVariable(); | |||
550 | if (DILocVar->isParameter()) { | |||
551 | DEBUG(dbgs() << " Include (parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include (parameter): "; } } while (false); | |||
552 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
553 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
554 | PDIRelated.insert(&*BI); | |||
555 | } else { | |||
556 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
557 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
558 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
559 | } | |||
560 | } else if (auto *DDI = dyn_cast<DbgDeclareInst>(&*BI)) { | |||
561 | DEBUG(dbgs() << " Deciding: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Deciding: "; } } while (false ); | |||
562 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
563 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
564 | DILocalVariable *DILocVar = DDI->getVariable(); | |||
565 | if (DILocVar->isParameter()) { | |||
566 | DEBUG(dbgs() << " Parameter: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Parameter: "; } } while ( false); | |||
567 | DEBUG(DILocVar->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { DILocVar->print(dbgs()); } } while (false ); | |||
568 | AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress()); | |||
569 | if (AI) { | |||
570 | DEBUG(dbgs() << " Processing alloca users: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Processing alloca users: " ; } } while (false); | |||
571 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
572 | for (User *U : AI->users()) { | |||
573 | if (StoreInst *SI = dyn_cast<StoreInst>(U)) { | |||
574 | if (Value *Arg = SI->getValueOperand()) { | |||
575 | if (dyn_cast<Argument>(Arg)) { | |||
576 | DEBUG(dbgs() << " Include: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include: "; } } while (false ); | |||
577 | DEBUG(AI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { AI->print(dbgs()); } } while (false); | |||
578 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
579 | PDIRelated.insert(AI); | |||
580 | DEBUG(dbgs() << " Include (parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include (parameter): "; } } while (false); | |||
581 | DEBUG(SI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { SI->print(dbgs()); } } while (false); | |||
582 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
583 | PDIRelated.insert(SI); | |||
584 | DEBUG(dbgs() << " Include: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Include: "; } } while (false ); | |||
585 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
586 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
587 | PDIRelated.insert(&*BI); | |||
588 | } else { | |||
589 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
590 | DEBUG(SI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { SI->print(dbgs()); } } while (false); | |||
591 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
592 | } | |||
593 | } | |||
594 | } else { | |||
595 | DEBUG(dbgs() << " Defer: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Defer: "; } } while (false ); | |||
596 | DEBUG(U->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { U->print(dbgs()); } } while (false); | |||
597 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
598 | } | |||
599 | } | |||
600 | } else { | |||
601 | DEBUG(dbgs() << " Delete (alloca NULL): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (alloca NULL): "; } } while (false); | |||
602 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
603 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
604 | } | |||
605 | } else { | |||
606 | DEBUG(dbgs() << " Delete (!parameter): ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Delete (!parameter): "; } } while (false); | |||
607 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
608 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
609 | } | |||
610 | } else if (dyn_cast<TerminatorInst>(BI) == GEntryBlock->getTerminator()) { | |||
611 | DEBUG(dbgs() << " Will Include Terminator: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Will Include Terminator: " ; } } while (false); | |||
612 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
613 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
614 | PDIRelated.insert(&*BI); | |||
615 | } else { | |||
616 | DEBUG(dbgs() << " Defer: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Defer: "; } } while (false ); | |||
617 | DEBUG(BI->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { BI->print(dbgs()); } } while (false); | |||
618 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
619 | } | |||
620 | } | |||
621 | DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " Report parameter debug info related/related instructions: {\n" ; } } while (false) | |||
622 | << " 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); | |||
623 | for (BasicBlock::iterator BI = GEntryBlock->begin(), BE = GEntryBlock->end(); | |||
624 | BI != BE; ++BI) { | |||
625 | ||||
626 | Instruction *I = &*BI; | |||
627 | if (PDIRelated.find(I) == PDIRelated.end()) { | |||
628 | DEBUG(dbgs() << " !PDIRelated: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " !PDIRelated: "; } } while (false); | |||
629 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
630 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
631 | PDIUnrelatedWL.push_back(I); | |||
632 | } else { | |||
633 | DEBUG(dbgs() << " PDIRelated: ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " PDIRelated: "; } } while (false); | |||
634 | DEBUG(I->print(dbgs()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { I->print(dbgs()); } } while (false); | |||
635 | DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "\n"; } } while (false); | |||
636 | } | |||
637 | } | |||
638 | DEBUG(dbgs() << " }\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " }\n"; } } while (false); | |||
639 | } | |||
640 | ||||
641 | // Replace G with a simple tail call to bitcast(F). Also (unless | |||
642 | // MergeFunctionsPDI holds) replace direct uses of G with bitcast(F), | |||
643 | // delete G. Under MergeFunctionsPDI, we use G itself for creating | |||
644 | // the thunk as we preserve the debug info (and associated instructions) | |||
645 | // from G's entry block pertaining to G's incoming arguments which are | |||
646 | // passed on as corresponding arguments in the call that G makes to F. | |||
647 | // For better debugability, under MergeFunctionsPDI, we do not modify G's | |||
648 | // call sites to point to F even when within the same translation unit. | |||
649 | void MergeFunctions::writeThunk(Function *F, Function *G) { | |||
650 | if (!G->isInterposable() && !MergeFunctionsPDI) { | |||
651 | if (G->hasGlobalUnnamedAddr()) { | |||
652 | // G might have been a key in our GlobalNumberState, and it's illegal | |||
653 | // to replace a key in ValueMap<GlobalValue *> with a non-global. | |||
654 | GlobalNumbers.erase(G); | |||
655 | // If G's address is not significant, replace it entirely. | |||
656 | Constant *BitcastF = ConstantExpr::getBitCast(F, G->getType()); | |||
657 | G->replaceAllUsesWith(BitcastF); | |||
658 | } else { | |||
659 | // Redirect direct callers of G to F. (See note on MergeFunctionsPDI | |||
660 | // above). | |||
661 | replaceDirectCallers(G, F); | |||
662 | } | |||
663 | } | |||
664 | ||||
665 | // If G was internal then we may have replaced all uses of G with F. If so, | |||
666 | // stop here and delete G. There's no need for a thunk. (See note on | |||
667 | // MergeFunctionsPDI above). | |||
668 | if (G->hasLocalLinkage() && G->use_empty() && !MergeFunctionsPDI) { | |||
669 | G->eraseFromParent(); | |||
670 | return; | |||
671 | } | |||
672 | ||||
673 | // Don't merge tiny functions using a thunk, since it can just end up | |||
674 | // making the function larger. | |||
675 | if (F->size() == 1) { | |||
676 | if (F->front().size() <= 2) { | |||
677 | DEBUG(dbgs() << "writeThunk: " << F->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: " << F-> getName() << " is too small to bother creating a thunk for\n" ; } } while (false) | |||
678 | << " is too small to bother creating a thunk for\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: " << F-> getName() << " is too small to bother creating a thunk for\n" ; } } while (false); | |||
679 | return; | |||
680 | } | |||
681 | } | |||
682 | ||||
683 | BasicBlock *GEntryBlock = nullptr; | |||
684 | std::vector<Instruction *> PDIUnrelatedWL; | |||
685 | BasicBlock *BB = nullptr; | |||
686 | Function *NewG = nullptr; | |||
687 | if (MergeFunctionsPDI) { | |||
688 | 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) | |||
689 | "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) | |||
690 | << 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); | |||
691 | GEntryBlock = &G->getEntryBlock(); | |||
692 | 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) | |||
693 | "debug info for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related " "debug info for " << G->getName() << "() {\n" ; } } while (false) | |||
694 | << G->getName() << "() {\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) filter parameter related " "debug info for " << G->getName() << "() {\n" ; } } while (false); | |||
695 | filterInstsUnrelatedToPDI(GEntryBlock, PDIUnrelatedWL); | |||
696 | GEntryBlock->getTerminator()->eraseFromParent(); | |||
697 | BB = GEntryBlock; | |||
698 | } else { | |||
699 | NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "", | |||
700 | G->getParent()); | |||
701 | BB = BasicBlock::Create(F->getContext(), "", NewG); | |||
702 | } | |||
703 | ||||
704 | IRBuilder<> Builder(BB); | |||
705 | Function *H = MergeFunctionsPDI ? G : NewG; | |||
706 | SmallVector<Value *, 16> Args; | |||
707 | unsigned i = 0; | |||
708 | FunctionType *FFTy = F->getFunctionType(); | |||
709 | for (Argument &AI : H->args()) { | |||
| ||||
710 | Args.push_back(createCast(Builder, &AI, FFTy->getParamType(i))); | |||
711 | ++i; | |||
712 | } | |||
713 | ||||
714 | CallInst *CI = Builder.CreateCall(F, Args); | |||
715 | ReturnInst *RI = nullptr; | |||
716 | CI->setTailCall(); | |||
717 | CI->setCallingConv(F->getCallingConv()); | |||
718 | CI->setAttributes(F->getAttributes()); | |||
719 | if (H->getReturnType()->isVoidTy()) { | |||
720 | RI = Builder.CreateRetVoid(); | |||
721 | } else { | |||
722 | RI = Builder.CreateRet(createCast(Builder, CI, H->getReturnType())); | |||
723 | } | |||
724 | ||||
725 | if (MergeFunctionsPDI) { | |||
726 | DISubprogram *DIS = G->getSubprogram(); | |||
727 | if (DIS) { | |||
728 | DebugLoc CIDbgLoc = DebugLoc::get(DIS->getScopeLine(), 0, DIS); | |||
729 | DebugLoc RIDbgLoc = DebugLoc::get(DIS->getScopeLine(), 0, DIS); | |||
730 | CI->setDebugLoc(CIDbgLoc); | |||
731 | RI->setDebugLoc(RIDbgLoc); | |||
732 | } else { | |||
733 | 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) | |||
734 | << G->getName() << "()\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: (MergeFunctionsPDI) No DISubprogram for " << G->getName() << "()\n"; } } while (false); | |||
735 | } | |||
736 | eraseTail(G); | |||
737 | eraseInstsUnrelatedToPDI(PDIUnrelatedWL); | |||
738 | 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) | |||
739 | << G->getName() << "()\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "} // End of parameter related debug info filtering for: " << G->getName() << "()\n"; } } while (false); | |||
740 | } else { | |||
741 | NewG->copyAttributesFrom(G); | |||
742 | NewG->takeName(G); | |||
743 | removeUsers(G); | |||
744 | G->replaceAllUsesWith(NewG); | |||
745 | G->eraseFromParent(); | |||
746 | } | |||
747 | ||||
748 | DEBUG(dbgs() << "writeThunk: " << H->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "writeThunk: " << H-> getName() << '\n'; } } while (false); | |||
749 | ++NumThunksWritten; | |||
750 | } | |||
751 | ||||
752 | // Merge two equivalent functions. Upon completion, Function G is deleted. | |||
753 | void MergeFunctions::mergeTwoFunctions(Function *F, Function *G) { | |||
754 | if (F->isInterposable()) { | |||
755 | assert(G->isInterposable())(static_cast <bool> (G->isInterposable()) ? void (0) : __assert_fail ("G->isInterposable()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 755, __extension__ __PRETTY_FUNCTION__)); | |||
756 | ||||
757 | // Make them both thunks to the same internal function. | |||
758 | Function *H = Function::Create(F->getFunctionType(), F->getLinkage(), "", | |||
759 | F->getParent()); | |||
760 | H->copyAttributesFrom(F); | |||
761 | H->takeName(F); | |||
762 | removeUsers(F); | |||
763 | F->replaceAllUsesWith(H); | |||
764 | ||||
765 | unsigned MaxAlignment = std::max(G->getAlignment(), H->getAlignment()); | |||
766 | ||||
767 | writeThunk(F, G); | |||
768 | writeThunk(F, H); | |||
769 | ||||
770 | F->setAlignment(MaxAlignment); | |||
771 | F->setLinkage(GlobalValue::PrivateLinkage); | |||
772 | ++NumDoubleWeak; | |||
773 | } else { | |||
774 | writeThunk(F, G); | |||
775 | } | |||
776 | ||||
777 | ++NumFunctionsMerged; | |||
778 | } | |||
779 | ||||
780 | /// Replace function F by function G. | |||
781 | void MergeFunctions::replaceFunctionInTree(const FunctionNode &FN, | |||
782 | Function *G) { | |||
783 | Function *F = FN.getFunc(); | |||
784 | assert(FunctionComparator(F, G, &GlobalNumbers).compare() == 0 &&(static_cast <bool> (FunctionComparator(F, G, &GlobalNumbers ).compare() == 0 && "The two functions must be equal" ) ? void (0) : __assert_fail ("FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && \"The two functions must be equal\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 785, __extension__ __PRETTY_FUNCTION__)) | |||
785 | "The two functions must be equal")(static_cast <bool> (FunctionComparator(F, G, &GlobalNumbers ).compare() == 0 && "The two functions must be equal" ) ? void (0) : __assert_fail ("FunctionComparator(F, G, &GlobalNumbers).compare() == 0 && \"The two functions must be equal\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 785, __extension__ __PRETTY_FUNCTION__)); | |||
786 | ||||
787 | auto I = FNodesInTree.find(F); | |||
788 | assert(I != FNodesInTree.end() && "F should be in FNodesInTree")(static_cast <bool> (I != FNodesInTree.end() && "F should be in FNodesInTree") ? void (0) : __assert_fail ("I != FNodesInTree.end() && \"F should be in FNodesInTree\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 788, __extension__ __PRETTY_FUNCTION__)); | |||
789 | assert(FNodesInTree.count(G) == 0 && "FNodesInTree should not contain G")(static_cast <bool> (FNodesInTree.count(G) == 0 && "FNodesInTree should not contain G") ? void (0) : __assert_fail ("FNodesInTree.count(G) == 0 && \"FNodesInTree should not contain G\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 789, __extension__ __PRETTY_FUNCTION__)); | |||
790 | ||||
791 | FnTreeType::iterator IterToFNInFnTree = I->second; | |||
792 | assert(&(*IterToFNInFnTree) == &FN && "F should map to FN in FNodesInTree.")(static_cast <bool> (&(*IterToFNInFnTree) == &FN && "F should map to FN in FNodesInTree.") ? void (0) : __assert_fail ("&(*IterToFNInFnTree) == &FN && \"F should map to FN in FNodesInTree.\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 792, __extension__ __PRETTY_FUNCTION__)); | |||
793 | // Remove F -> FN and insert G -> FN | |||
794 | FNodesInTree.erase(I); | |||
795 | FNodesInTree.insert({G, IterToFNInFnTree}); | |||
796 | // Replace F with G in FN, which is stored inside the FnTree. | |||
797 | FN.replaceBy(G); | |||
798 | } | |||
799 | ||||
800 | // Insert a ComparableFunction into the FnTree, or merge it away if equal to one | |||
801 | // that was already inserted. | |||
802 | bool MergeFunctions::insert(Function *NewFunction) { | |||
803 | std::pair<FnTreeType::iterator, bool> Result = | |||
804 | FnTree.insert(FunctionNode(NewFunction)); | |||
805 | ||||
806 | if (Result.second) { | |||
807 | assert(FNodesInTree.count(NewFunction) == 0)(static_cast <bool> (FNodesInTree.count(NewFunction) == 0) ? void (0) : __assert_fail ("FNodesInTree.count(NewFunction) == 0" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 807, __extension__ __PRETTY_FUNCTION__)); | |||
808 | FNodesInTree.insert({NewFunction, Result.first}); | |||
809 | DEBUG(dbgs() << "Inserting as unique: " << NewFunction->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "Inserting as unique: " << NewFunction->getName() << '\n'; } } while (false); | |||
810 | return false; | |||
811 | } | |||
812 | ||||
813 | const FunctionNode &OldF = *Result.first; | |||
814 | ||||
815 | // Impose a total order (by name) on the replacement of functions. This is | |||
816 | // important when operating on more than one module independently to prevent | |||
817 | // cycles of thunks calling each other when the modules are linked together. | |||
818 | // | |||
819 | // First of all, we process strong functions before weak functions. | |||
820 | if ((OldF.getFunc()->isInterposable() && !NewFunction->isInterposable()) || | |||
821 | (OldF.getFunc()->isInterposable() == NewFunction->isInterposable() && | |||
822 | OldF.getFunc()->getName() > NewFunction->getName())) { | |||
823 | // Swap the two functions. | |||
824 | Function *F = OldF.getFunc(); | |||
825 | replaceFunctionInTree(*Result.first, NewFunction); | |||
826 | NewFunction = F; | |||
827 | assert(OldF.getFunc() != F && "Must have swapped the functions.")(static_cast <bool> (OldF.getFunc() != F && "Must have swapped the functions." ) ? void (0) : __assert_fail ("OldF.getFunc() != F && \"Must have swapped the functions.\"" , "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/IPO/MergeFunctions.cpp" , 827, __extension__ __PRETTY_FUNCTION__)); | |||
828 | } | |||
829 | ||||
830 | DEBUG(dbgs() << " " << OldF.getFunc()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " " << OldF.getFunc() ->getName() << " == " << NewFunction->getName () << '\n'; } } while (false) | |||
831 | << " == " << NewFunction->getName() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << " " << OldF.getFunc() ->getName() << " == " << NewFunction->getName () << '\n'; } } while (false); | |||
832 | ||||
833 | Function *DeleteF = NewFunction; | |||
834 | mergeTwoFunctions(OldF.getFunc(), DeleteF); | |||
835 | return true; | |||
836 | } | |||
837 | ||||
838 | // Remove a function from FnTree. If it was already in FnTree, add | |||
839 | // it to Deferred so that we'll look at it in the next round. | |||
840 | void MergeFunctions::remove(Function *F) { | |||
841 | auto I = FNodesInTree.find(F); | |||
842 | if (I != FNodesInTree.end()) { | |||
843 | DEBUG(dbgs() << "Deferred " << F->getName()<< ".\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("mergefunc")) { dbgs() << "Deferred " << F->getName ()<< ".\n"; } } while (false); | |||
844 | FnTree.erase(I->second); | |||
845 | // I->second has been invalidated, remove it from the FNodesInTree map to | |||
846 | // preserve the invariant. | |||
847 | FNodesInTree.erase(I); | |||
848 | Deferred.emplace_back(F); | |||
849 | } | |||
850 | } | |||
851 | ||||
852 | // For each instruction used by the value, remove() the function that contains | |||
853 | // the instruction. This should happen right before a call to RAUW. | |||
854 | void MergeFunctions::removeUsers(Value *V) { | |||
855 | std::vector<Value *> Worklist; | |||
856 | Worklist.push_back(V); | |||
857 | SmallSet<Value*, 8> Visited; | |||
858 | Visited.insert(V); | |||
859 | while (!Worklist.empty()) { | |||
860 | Value *V = Worklist.back(); | |||
861 | Worklist.pop_back(); | |||
862 | ||||
863 | for (User *U : V->users()) { | |||
864 | if (Instruction *I = dyn_cast<Instruction>(U)) { | |||
865 | remove(I->getParent()->getParent()); | |||
866 | } else if (isa<GlobalValue>(U)) { | |||
867 | // do nothing | |||
868 | } else if (Constant *C = dyn_cast<Constant>(U)) { | |||
869 | for (User *UU : C->users()) { | |||
870 | if (!Visited.insert(UU).second) | |||
871 | Worklist.push_back(UU); | |||
872 | } | |||
873 | } | |||
874 | } | |||
875 | } | |||
876 | } |