/3rd_party/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp

https://code.google.com/p/softart/ · C++ · 372 lines · 307 code · 38 blank · 27 comment · 71 complexity · 4bb6c917e64d920a956c4e38fdfa3dd9 MD5 · raw file

  1. //===- AliasAnalysisEvaluator.cpp - Alias Analysis Accuracy Evaluator -----===//
  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 file implements a simple N^2 alias analysis accuracy evaluator.
  11. // Basically, for each function in the program, it simply queries to see how the
  12. // alias analysis implementation answers alias queries between each pair of
  13. // pointers in the function.
  14. //
  15. // This is inspired and adapted from code by: Naveen Neelakantam, Francesco
  16. // Spadini, and Wojciech Stryjewski.
  17. //
  18. //===----------------------------------------------------------------------===//
  19. #include "llvm/Analysis/Passes.h"
  20. #include "llvm/ADT/SetVector.h"
  21. #include "llvm/Analysis/AliasAnalysis.h"
  22. #include "llvm/Assembly/Writer.h"
  23. #include "llvm/IR/Constants.h"
  24. #include "llvm/IR/DerivedTypes.h"
  25. #include "llvm/IR/Function.h"
  26. #include "llvm/IR/Instructions.h"
  27. #include "llvm/Pass.h"
  28. #include "llvm/Support/CommandLine.h"
  29. #include "llvm/Support/Debug.h"
  30. #include "llvm/Support/InstIterator.h"
  31. #include "llvm/Support/raw_ostream.h"
  32. using namespace llvm;
  33. static cl::opt<bool> PrintAll("print-all-alias-modref-info", cl::ReallyHidden);
  34. static cl::opt<bool> PrintNoAlias("print-no-aliases", cl::ReallyHidden);
  35. static cl::opt<bool> PrintMayAlias("print-may-aliases", cl::ReallyHidden);
  36. static cl::opt<bool> PrintPartialAlias("print-partial-aliases", cl::ReallyHidden);
  37. static cl::opt<bool> PrintMustAlias("print-must-aliases", cl::ReallyHidden);
  38. static cl::opt<bool> PrintNoModRef("print-no-modref", cl::ReallyHidden);
  39. static cl::opt<bool> PrintMod("print-mod", cl::ReallyHidden);
  40. static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
  41. static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
  42. static cl::opt<bool> EvalTBAA("evaluate-tbaa", cl::ReallyHidden);
  43. namespace {
  44. class AAEval : public FunctionPass {
  45. unsigned NoAlias, MayAlias, PartialAlias, MustAlias;
  46. unsigned NoModRef, Mod, Ref, ModRef;
  47. public:
  48. static char ID; // Pass identification, replacement for typeid
  49. AAEval() : FunctionPass(ID) {
  50. initializeAAEvalPass(*PassRegistry::getPassRegistry());
  51. }
  52. virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  53. AU.addRequired<AliasAnalysis>();
  54. AU.setPreservesAll();
  55. }
  56. bool doInitialization(Module &M) {
  57. NoAlias = MayAlias = PartialAlias = MustAlias = 0;
  58. NoModRef = Mod = Ref = ModRef = 0;
  59. if (PrintAll) {
  60. PrintNoAlias = PrintMayAlias = true;
  61. PrintPartialAlias = PrintMustAlias = true;
  62. PrintNoModRef = PrintMod = PrintRef = PrintModRef = true;
  63. }
  64. return false;
  65. }
  66. bool runOnFunction(Function &F);
  67. bool doFinalization(Module &M);
  68. };
  69. }
  70. char AAEval::ID = 0;
  71. INITIALIZE_PASS_BEGIN(AAEval, "aa-eval",
  72. "Exhaustive Alias Analysis Precision Evaluator", false, true)
  73. INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
  74. INITIALIZE_PASS_END(AAEval, "aa-eval",
  75. "Exhaustive Alias Analysis Precision Evaluator", false, true)
  76. FunctionPass *llvm::createAAEvalPass() { return new AAEval(); }
  77. static void PrintResults(const char *Msg, bool P, const Value *V1,
  78. const Value *V2, const Module *M) {
  79. if (P) {
  80. std::string o1, o2;
  81. {
  82. raw_string_ostream os1(o1), os2(o2);
  83. WriteAsOperand(os1, V1, true, M);
  84. WriteAsOperand(os2, V2, true, M);
  85. }
  86. if (o2 < o1)
  87. std::swap(o1, o2);
  88. errs() << " " << Msg << ":\t"
  89. << o1 << ", "
  90. << o2 << "\n";
  91. }
  92. }
  93. static inline void
  94. PrintModRefResults(const char *Msg, bool P, Instruction *I, Value *Ptr,
  95. Module *M) {
  96. if (P) {
  97. errs() << " " << Msg << ": Ptr: ";
  98. WriteAsOperand(errs(), Ptr, true, M);
  99. errs() << "\t<->" << *I << '\n';
  100. }
  101. }
  102. static inline void
  103. PrintModRefResults(const char *Msg, bool P, CallSite CSA, CallSite CSB,
  104. Module *M) {
  105. if (P) {
  106. errs() << " " << Msg << ": " << *CSA.getInstruction()
  107. << " <-> " << *CSB.getInstruction() << '\n';
  108. }
  109. }
  110. static inline void
  111. PrintLoadStoreResults(const char *Msg, bool P, const Value *V1,
  112. const Value *V2, const Module *M) {
  113. if (P) {
  114. errs() << " " << Msg << ": " << *V1
  115. << " <-> " << *V2 << '\n';
  116. }
  117. }
  118. static inline bool isInterestingPointer(Value *V) {
  119. return V->getType()->isPointerTy()
  120. && !isa<ConstantPointerNull>(V);
  121. }
  122. bool AAEval::runOnFunction(Function &F) {
  123. AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
  124. SetVector<Value *> Pointers;
  125. SetVector<CallSite> CallSites;
  126. SetVector<Value *> Loads;
  127. SetVector<Value *> Stores;
  128. for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
  129. if (I->getType()->isPointerTy()) // Add all pointer arguments.
  130. Pointers.insert(I);
  131. for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
  132. if (I->getType()->isPointerTy()) // Add all pointer instructions.
  133. Pointers.insert(&*I);
  134. if (EvalTBAA && isa<LoadInst>(&*I))
  135. Loads.insert(&*I);
  136. if (EvalTBAA && isa<StoreInst>(&*I))
  137. Stores.insert(&*I);
  138. Instruction &Inst = *I;
  139. if (CallSite CS = cast<Value>(&Inst)) {
  140. Value *Callee = CS.getCalledValue();
  141. // Skip actual functions for direct function calls.
  142. if (!isa<Function>(Callee) && isInterestingPointer(Callee))
  143. Pointers.insert(Callee);
  144. // Consider formals.
  145. for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
  146. AI != AE; ++AI)
  147. if (isInterestingPointer(*AI))
  148. Pointers.insert(*AI);
  149. CallSites.insert(CS);
  150. } else {
  151. // Consider all operands.
  152. for (Instruction::op_iterator OI = Inst.op_begin(), OE = Inst.op_end();
  153. OI != OE; ++OI)
  154. if (isInterestingPointer(*OI))
  155. Pointers.insert(*OI);
  156. }
  157. }
  158. if (PrintNoAlias || PrintMayAlias || PrintPartialAlias || PrintMustAlias ||
  159. PrintNoModRef || PrintMod || PrintRef || PrintModRef)
  160. errs() << "Function: " << F.getName() << ": " << Pointers.size()
  161. << " pointers, " << CallSites.size() << " call sites\n";
  162. // iterate over the worklist, and run the full (n^2)/2 disambiguations
  163. for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
  164. I1 != E; ++I1) {
  165. uint64_t I1Size = AliasAnalysis::UnknownSize;
  166. Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
  167. if (I1ElTy->isSized()) I1Size = AA.getTypeStoreSize(I1ElTy);
  168. for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
  169. uint64_t I2Size = AliasAnalysis::UnknownSize;
  170. Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
  171. if (I2ElTy->isSized()) I2Size = AA.getTypeStoreSize(I2ElTy);
  172. switch (AA.alias(*I1, I1Size, *I2, I2Size)) {
  173. case AliasAnalysis::NoAlias:
  174. PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
  175. ++NoAlias; break;
  176. case AliasAnalysis::MayAlias:
  177. PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
  178. ++MayAlias; break;
  179. case AliasAnalysis::PartialAlias:
  180. PrintResults("PartialAlias", PrintPartialAlias, *I1, *I2,
  181. F.getParent());
  182. ++PartialAlias; break;
  183. case AliasAnalysis::MustAlias:
  184. PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
  185. ++MustAlias; break;
  186. }
  187. }
  188. }
  189. if (EvalTBAA) {
  190. // iterate over all pairs of load, store
  191. for (SetVector<Value *>::iterator I1 = Loads.begin(), E = Loads.end();
  192. I1 != E; ++I1) {
  193. for (SetVector<Value *>::iterator I2 = Stores.begin(), E2 = Stores.end();
  194. I2 != E2; ++I2) {
  195. switch (AA.alias(AA.getLocation(cast<LoadInst>(*I1)),
  196. AA.getLocation(cast<StoreInst>(*I2)))) {
  197. case AliasAnalysis::NoAlias:
  198. PrintLoadStoreResults("NoAlias", PrintNoAlias, *I1, *I2,
  199. F.getParent());
  200. ++NoAlias; break;
  201. case AliasAnalysis::MayAlias:
  202. PrintLoadStoreResults("MayAlias", PrintMayAlias, *I1, *I2,
  203. F.getParent());
  204. ++MayAlias; break;
  205. case AliasAnalysis::PartialAlias:
  206. PrintLoadStoreResults("PartialAlias", PrintPartialAlias, *I1, *I2,
  207. F.getParent());
  208. ++PartialAlias; break;
  209. case AliasAnalysis::MustAlias:
  210. PrintLoadStoreResults("MustAlias", PrintMustAlias, *I1, *I2,
  211. F.getParent());
  212. ++MustAlias; break;
  213. }
  214. }
  215. }
  216. // iterate over all pairs of store, store
  217. for (SetVector<Value *>::iterator I1 = Stores.begin(), E = Stores.end();
  218. I1 != E; ++I1) {
  219. for (SetVector<Value *>::iterator I2 = Stores.begin(); I2 != I1; ++I2) {
  220. switch (AA.alias(AA.getLocation(cast<StoreInst>(*I1)),
  221. AA.getLocation(cast<StoreInst>(*I2)))) {
  222. case AliasAnalysis::NoAlias:
  223. PrintLoadStoreResults("NoAlias", PrintNoAlias, *I1, *I2,
  224. F.getParent());
  225. ++NoAlias; break;
  226. case AliasAnalysis::MayAlias:
  227. PrintLoadStoreResults("MayAlias", PrintMayAlias, *I1, *I2,
  228. F.getParent());
  229. ++MayAlias; break;
  230. case AliasAnalysis::PartialAlias:
  231. PrintLoadStoreResults("PartialAlias", PrintPartialAlias, *I1, *I2,
  232. F.getParent());
  233. ++PartialAlias; break;
  234. case AliasAnalysis::MustAlias:
  235. PrintLoadStoreResults("MustAlias", PrintMustAlias, *I1, *I2,
  236. F.getParent());
  237. ++MustAlias; break;
  238. }
  239. }
  240. }
  241. }
  242. // Mod/ref alias analysis: compare all pairs of calls and values
  243. for (SetVector<CallSite>::iterator C = CallSites.begin(),
  244. Ce = CallSites.end(); C != Ce; ++C) {
  245. Instruction *I = C->getInstruction();
  246. for (SetVector<Value *>::iterator V = Pointers.begin(), Ve = Pointers.end();
  247. V != Ve; ++V) {
  248. uint64_t Size = AliasAnalysis::UnknownSize;
  249. Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
  250. if (ElTy->isSized()) Size = AA.getTypeStoreSize(ElTy);
  251. switch (AA.getModRefInfo(*C, *V, Size)) {
  252. case AliasAnalysis::NoModRef:
  253. PrintModRefResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
  254. ++NoModRef; break;
  255. case AliasAnalysis::Mod:
  256. PrintModRefResults("Just Mod", PrintMod, I, *V, F.getParent());
  257. ++Mod; break;
  258. case AliasAnalysis::Ref:
  259. PrintModRefResults("Just Ref", PrintRef, I, *V, F.getParent());
  260. ++Ref; break;
  261. case AliasAnalysis::ModRef:
  262. PrintModRefResults("Both ModRef", PrintModRef, I, *V, F.getParent());
  263. ++ModRef; break;
  264. }
  265. }
  266. }
  267. // Mod/ref alias analysis: compare all pairs of calls
  268. for (SetVector<CallSite>::iterator C = CallSites.begin(),
  269. Ce = CallSites.end(); C != Ce; ++C) {
  270. for (SetVector<CallSite>::iterator D = CallSites.begin(); D != Ce; ++D) {
  271. if (D == C)
  272. continue;
  273. switch (AA.getModRefInfo(*C, *D)) {
  274. case AliasAnalysis::NoModRef:
  275. PrintModRefResults("NoModRef", PrintNoModRef, *C, *D, F.getParent());
  276. ++NoModRef; break;
  277. case AliasAnalysis::Mod:
  278. PrintModRefResults("Just Mod", PrintMod, *C, *D, F.getParent());
  279. ++Mod; break;
  280. case AliasAnalysis::Ref:
  281. PrintModRefResults("Just Ref", PrintRef, *C, *D, F.getParent());
  282. ++Ref; break;
  283. case AliasAnalysis::ModRef:
  284. PrintModRefResults("Both ModRef", PrintModRef, *C, *D, F.getParent());
  285. ++ModRef; break;
  286. }
  287. }
  288. }
  289. return false;
  290. }
  291. static void PrintPercent(unsigned Num, unsigned Sum) {
  292. errs() << "(" << Num*100ULL/Sum << "."
  293. << ((Num*1000ULL/Sum) % 10) << "%)\n";
  294. }
  295. bool AAEval::doFinalization(Module &M) {
  296. unsigned AliasSum = NoAlias + MayAlias + PartialAlias + MustAlias;
  297. errs() << "===== Alias Analysis Evaluator Report =====\n";
  298. if (AliasSum == 0) {
  299. errs() << " Alias Analysis Evaluator Summary: No pointers!\n";
  300. } else {
  301. errs() << " " << AliasSum << " Total Alias Queries Performed\n";
  302. errs() << " " << NoAlias << " no alias responses ";
  303. PrintPercent(NoAlias, AliasSum);
  304. errs() << " " << MayAlias << " may alias responses ";
  305. PrintPercent(MayAlias, AliasSum);
  306. errs() << " " << PartialAlias << " partial alias responses ";
  307. PrintPercent(PartialAlias, AliasSum);
  308. errs() << " " << MustAlias << " must alias responses ";
  309. PrintPercent(MustAlias, AliasSum);
  310. errs() << " Alias Analysis Evaluator Pointer Alias Summary: "
  311. << NoAlias*100/AliasSum << "%/" << MayAlias*100/AliasSum << "%/"
  312. << PartialAlias*100/AliasSum << "%/"
  313. << MustAlias*100/AliasSum << "%\n";
  314. }
  315. // Display the summary for mod/ref analysis
  316. unsigned ModRefSum = NoModRef + Mod + Ref + ModRef;
  317. if (ModRefSum == 0) {
  318. errs() << " Alias Analysis Mod/Ref Evaluator Summary: no mod/ref!\n";
  319. } else {
  320. errs() << " " << ModRefSum << " Total ModRef Queries Performed\n";
  321. errs() << " " << NoModRef << " no mod/ref responses ";
  322. PrintPercent(NoModRef, ModRefSum);
  323. errs() << " " << Mod << " mod responses ";
  324. PrintPercent(Mod, ModRefSum);
  325. errs() << " " << Ref << " ref responses ";
  326. PrintPercent(Ref, ModRefSum);
  327. errs() << " " << ModRef << " mod & ref responses ";
  328. PrintPercent(ModRef, ModRefSum);
  329. errs() << " Alias Analysis Evaluator Mod/Ref Summary: "
  330. << NoModRef*100/ModRefSum << "%/" << Mod*100/ModRefSum << "%/"
  331. << Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";
  332. }
  333. return false;
  334. }