/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/Analysis/LiveVariables.cpp
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1 | | //=- LiveVariables.cpp - Live Variable Analysis for Source CFGs ----------*-==// |
2 | | // |
3 | | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | // See https://llvm.org/LICENSE.txt for license information. |
5 | | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | // |
7 | | //===----------------------------------------------------------------------===// |
8 | | // |
9 | | // This file implements Live Variables analysis for source-level CFGs. |
10 | | // |
11 | | //===----------------------------------------------------------------------===// |
12 | | |
13 | | #include "clang/Analysis/Analyses/LiveVariables.h" |
14 | | #include "clang/AST/Stmt.h" |
15 | | #include "clang/AST/StmtVisitor.h" |
16 | | #include "clang/Analysis/AnalysisDeclContext.h" |
17 | | #include "clang/Analysis/CFG.h" |
18 | | #include "clang/Analysis/FlowSensitive/DataflowWorklist.h" |
19 | | #include "llvm/ADT/DenseMap.h" |
20 | | #include "llvm/Support/raw_ostream.h" |
21 | | #include <algorithm> |
22 | | #include <vector> |
23 | | |
24 | | using namespace clang; |
25 | | |
26 | | namespace { |
27 | | class LiveVariablesImpl { |
28 | | public: |
29 | | AnalysisDeclContext &analysisContext; |
30 | | llvm::ImmutableSet<const Expr *>::Factory ESetFact; |
31 | | llvm::ImmutableSet<const VarDecl *>::Factory DSetFact; |
32 | | llvm::ImmutableSet<const BindingDecl *>::Factory BSetFact; |
33 | | llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues> blocksEndToLiveness; |
34 | | llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues> blocksBeginToLiveness; |
35 | | llvm::DenseMap<const Stmt *, LiveVariables::LivenessValues> stmtsToLiveness; |
36 | | llvm::DenseMap<const DeclRefExpr *, unsigned> inAssignment; |
37 | | const bool killAtAssign; |
38 | | |
39 | | LiveVariables::LivenessValues |
40 | | merge(LiveVariables::LivenessValues valsA, |
41 | | LiveVariables::LivenessValues valsB); |
42 | | |
43 | | LiveVariables::LivenessValues |
44 | | runOnBlock(const CFGBlock *block, LiveVariables::LivenessValues val, |
45 | | LiveVariables::Observer *obs = nullptr); |
46 | | |
47 | | void dumpBlockLiveness(const SourceManager& M); |
48 | | void dumpExprLiveness(const SourceManager& M); |
49 | | |
50 | | LiveVariablesImpl(AnalysisDeclContext &ac, bool KillAtAssign) |
51 | | : analysisContext(ac), |
52 | | ESetFact(false), // Do not canonicalize ImmutableSets by default. |
53 | | DSetFact(false), // This is a *major* performance win. |
54 | 27.1k | BSetFact(false), killAtAssign(KillAtAssign) {} |
55 | | }; |
56 | | } // namespace |
57 | | |
58 | 2.13M | static LiveVariablesImpl &getImpl(void *x) { |
59 | 2.13M | return *((LiveVariablesImpl *) x); |
60 | 2.13M | } |
61 | | |
62 | | //===----------------------------------------------------------------------===// |
63 | | // Operations and queries on LivenessValues. |
64 | | //===----------------------------------------------------------------------===// |
65 | | |
66 | 1.49M | bool LiveVariables::LivenessValues::isLive(const Expr *E) const { |
67 | 1.49M | return liveExprs.contains(E); |
68 | 1.49M | } |
69 | | |
70 | 636k | bool LiveVariables::LivenessValues::isLive(const VarDecl *D) const { |
71 | 636k | if (const auto *DD = dyn_cast<DecompositionDecl>(D)) { |
72 | 142 | bool alive = false; |
73 | 142 | for (const BindingDecl *BD : DD->bindings()) |
74 | 344 | alive |= liveBindings.contains(BD); |
75 | 142 | return alive; |
76 | 142 | } |
77 | 636k | return liveDecls.contains(D); |
78 | 636k | } |
79 | | |
80 | | namespace { |
81 | | template <typename SET> |
82 | 248k | SET mergeSets(SET A, SET B) { |
83 | 248k | if (A.isEmpty()) |
84 | 240k | return B; |
85 | | |
86 | 15.1k | for (typename SET::iterator it = B.begin(), ei = B.end(); 7.59k it != ei; ++it7.51k ) { |
87 | 7.51k | A = A.add(*it); |
88 | 7.51k | } |
89 | 7.59k | return A; |
90 | 248k | } LiveVariables.cpp:llvm::ImmutableSetRef<clang::Expr const*, llvm::ImutContainerInfo<clang::Expr const*> > (anonymous namespace)::mergeSets<llvm::ImmutableSetRef<clang::Expr const*, llvm::ImutContainerInfo<clang::Expr const*> > >(llvm::ImmutableSetRef<clang::Expr const*, llvm::ImutContainerInfo<clang::Expr const*> >, llvm::ImmutableSetRef<clang::Expr const*, llvm::ImutContainerInfo<clang::Expr const*> >) Line | Count | Source | 82 | 82.7k | SET mergeSets(SET A, SET B) { | 83 | 82.7k | if (A.isEmpty()) | 84 | 80.9k | return B; | 85 | | | 86 | 4.58k | for (typename SET::iterator it = B.begin(), ei = B.end(); 1.74k it != ei; ++it2.84k ) { | 87 | 2.84k | A = A.add(*it); | 88 | 2.84k | } | 89 | 1.74k | return A; | 90 | 82.7k | } |
LiveVariables.cpp:llvm::ImmutableSetRef<clang::VarDecl const*, llvm::ImutContainerInfo<clang::VarDecl const*> > (anonymous namespace)::mergeSets<llvm::ImmutableSetRef<clang::VarDecl const*, llvm::ImutContainerInfo<clang::VarDecl const*> > >(llvm::ImmutableSetRef<clang::VarDecl const*, llvm::ImutContainerInfo<clang::VarDecl const*> >, llvm::ImmutableSetRef<clang::VarDecl const*, llvm::ImutContainerInfo<clang::VarDecl const*> >) Line | Count | Source | 82 | 82.7k | SET mergeSets(SET A, SET B) { | 83 | 82.7k | if (A.isEmpty()) | 84 | 76.8k | return B; | 85 | | | 86 | 10.5k | for (typename SET::iterator it = B.begin(), ei = B.end(); 5.85k it != ei; ++it4.66k ) { | 87 | 4.66k | A = A.add(*it); | 88 | 4.66k | } | 89 | 5.85k | return A; | 90 | 82.7k | } |
LiveVariables.cpp:llvm::ImmutableSetRef<clang::BindingDecl const*, llvm::ImutContainerInfo<clang::BindingDecl const*> > (anonymous namespace)::mergeSets<llvm::ImmutableSetRef<clang::BindingDecl const*, llvm::ImutContainerInfo<clang::BindingDecl const*> > >(llvm::ImmutableSetRef<clang::BindingDecl const*, llvm::ImutContainerInfo<clang::BindingDecl const*> >, llvm::ImmutableSetRef<clang::BindingDecl const*, llvm::ImutContainerInfo<clang::BindingDecl const*> >) Line | Count | Source | 82 | 82.7k | SET mergeSets(SET A, SET B) { | 83 | 82.7k | if (A.isEmpty()) | 84 | 82.7k | return B; | 85 | | | 86 | 0 | for (typename SET::iterator it = B.begin(), ei = B.end(); it != ei; ++it) { | 87 | 0 | A = A.add(*it); | 88 | 0 | } | 89 | 0 | return A; | 90 | 82.7k | } |
|
91 | | } // namespace |
92 | | |
93 | 0 | void LiveVariables::Observer::anchor() { } |
94 | | |
95 | | LiveVariables::LivenessValues |
96 | | LiveVariablesImpl::merge(LiveVariables::LivenessValues valsA, |
97 | 82.7k | LiveVariables::LivenessValues valsB) { |
98 | | |
99 | 82.7k | llvm::ImmutableSetRef<const Expr *> SSetRefA( |
100 | 82.7k | valsA.liveExprs.getRootWithoutRetain(), ESetFact.getTreeFactory()), |
101 | 82.7k | SSetRefB(valsB.liveExprs.getRootWithoutRetain(), |
102 | 82.7k | ESetFact.getTreeFactory()); |
103 | | |
104 | 82.7k | llvm::ImmutableSetRef<const VarDecl *> |
105 | 82.7k | DSetRefA(valsA.liveDecls.getRootWithoutRetain(), DSetFact.getTreeFactory()), |
106 | 82.7k | DSetRefB(valsB.liveDecls.getRootWithoutRetain(), DSetFact.getTreeFactory()); |
107 | | |
108 | 82.7k | llvm::ImmutableSetRef<const BindingDecl *> |
109 | 82.7k | BSetRefA(valsA.liveBindings.getRootWithoutRetain(), BSetFact.getTreeFactory()), |
110 | 82.7k | BSetRefB(valsB.liveBindings.getRootWithoutRetain(), BSetFact.getTreeFactory()); |
111 | | |
112 | 82.7k | SSetRefA = mergeSets(SSetRefA, SSetRefB); |
113 | 82.7k | DSetRefA = mergeSets(DSetRefA, DSetRefB); |
114 | 82.7k | BSetRefA = mergeSets(BSetRefA, BSetRefB); |
115 | | |
116 | | // asImmutableSet() canonicalizes the tree, allowing us to do an easy |
117 | | // comparison afterwards. |
118 | 82.7k | return LiveVariables::LivenessValues(SSetRefA.asImmutableSet(), |
119 | 82.7k | DSetRefA.asImmutableSet(), |
120 | 82.7k | BSetRefA.asImmutableSet()); |
121 | 82.7k | } |
122 | | |
123 | 3.62k | bool LiveVariables::LivenessValues::equals(const LivenessValues &V) const { |
124 | 3.62k | return liveExprs == V.liveExprs && liveDecls == V.liveDecls3.01k ; |
125 | 3.62k | } |
126 | | |
127 | | //===----------------------------------------------------------------------===// |
128 | | // Query methods. |
129 | | //===----------------------------------------------------------------------===// |
130 | | |
131 | 732k | static bool isAlwaysAlive(const VarDecl *D) { |
132 | 732k | return D->hasGlobalStorage(); |
133 | 732k | } |
134 | | |
135 | 0 | bool LiveVariables::isLive(const CFGBlock *B, const VarDecl *D) { |
136 | 0 | return isAlwaysAlive(D) || getImpl(impl).blocksEndToLiveness[B].isLive(D); |
137 | 0 | } |
138 | | |
139 | 635k | bool LiveVariables::isLive(const Stmt *S, const VarDecl *D) { |
140 | 635k | return isAlwaysAlive(D) || getImpl(impl).stmtsToLiveness[S].isLive(D); |
141 | 635k | } |
142 | | |
143 | 1.49M | bool LiveVariables::isLive(const Stmt *Loc, const Expr *Val) { |
144 | 1.49M | return getImpl(impl).stmtsToLiveness[Loc].isLive(Val); |
145 | 1.49M | } |
146 | | |
147 | | //===----------------------------------------------------------------------===// |
148 | | // Dataflow computation. |
149 | | //===----------------------------------------------------------------------===// |
150 | | |
151 | | namespace { |
152 | | class TransferFunctions : public StmtVisitor<TransferFunctions> { |
153 | | LiveVariablesImpl &LV; |
154 | | LiveVariables::LivenessValues &val; |
155 | | LiveVariables::Observer *observer; |
156 | | const CFGBlock *currentBlock; |
157 | | public: |
158 | | TransferFunctions(LiveVariablesImpl &im, |
159 | | LiveVariables::LivenessValues &Val, |
160 | | LiveVariables::Observer *Observer, |
161 | | const CFGBlock *CurrentBlock) |
162 | 102k | : LV(im), val(Val), observer(Observer), currentBlock(CurrentBlock) {} |
163 | | |
164 | | void VisitBinaryOperator(BinaryOperator *BO); |
165 | | void VisitBlockExpr(BlockExpr *BE); |
166 | | void VisitDeclRefExpr(DeclRefExpr *DR); |
167 | | void VisitDeclStmt(DeclStmt *DS); |
168 | | void VisitObjCForCollectionStmt(ObjCForCollectionStmt *OS); |
169 | | void VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *UE); |
170 | | void VisitUnaryOperator(UnaryOperator *UO); |
171 | | void Visit(Stmt *S); |
172 | | }; |
173 | | } // namespace |
174 | | |
175 | 22.7k | static const VariableArrayType *FindVA(QualType Ty) { |
176 | 22.7k | const Type *ty = Ty.getTypePtr(); |
177 | 24.2k | while (const ArrayType *VT = dyn_cast<ArrayType>(ty)) { |
178 | 1.60k | if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(VT)) |
179 | 64 | if (VAT->getSizeExpr()) |
180 | 64 | return VAT; |
181 | | |
182 | 1.54k | ty = VT->getElementType().getTypePtr(); |
183 | 1.54k | } |
184 | | |
185 | 22.6k | return nullptr; |
186 | 22.7k | } |
187 | | |
188 | 422k | static const Expr *LookThroughExpr(const Expr *E) { |
189 | 428k | while (E) { |
190 | 428k | if (const Expr *Ex = dyn_cast<Expr>(E)) |
191 | 428k | E = Ex->IgnoreParens(); |
192 | 428k | if (const FullExpr *FE = dyn_cast<FullExpr>(E)) { |
193 | 5.28k | E = FE->getSubExpr(); |
194 | 5.28k | continue; |
195 | 5.28k | } |
196 | 423k | if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) { |
197 | 780 | E = OVE->getSourceExpr(); |
198 | 780 | continue; |
199 | 780 | } |
200 | 422k | break; |
201 | 423k | } |
202 | 422k | return E; |
203 | 422k | } |
204 | | |
205 | | static void AddLiveExpr(llvm::ImmutableSet<const Expr *> &Set, |
206 | | llvm::ImmutableSet<const Expr *>::Factory &F, |
207 | 422k | const Expr *E) { |
208 | 422k | Set = F.add(Set, LookThroughExpr(E)); |
209 | 422k | } |
210 | | |
211 | 501k | void TransferFunctions::Visit(Stmt *S) { |
212 | 501k | if (observer) |
213 | 9.05k | observer->observeStmt(S, currentBlock, val); |
214 | | |
215 | 501k | StmtVisitor<TransferFunctions>::Visit(S); |
216 | | |
217 | 501k | if (const auto *E = dyn_cast<Expr>(S)) { |
218 | 461k | val.liveExprs = LV.ESetFact.remove(val.liveExprs, E); |
219 | 461k | } |
220 | | |
221 | | // Mark all children expressions live. |
222 | | |
223 | 501k | switch (S->getStmtClass()) { |
224 | 459k | default: |
225 | 459k | break; |
226 | 459k | case Stmt::StmtExprClass: { |
227 | | // For statement expressions, look through the compound statement. |
228 | 130 | S = cast<StmtExpr>(S)->getSubStmt(); |
229 | 130 | break; |
230 | 0 | } |
231 | 6.13k | case Stmt::CXXMemberCallExprClass: { |
232 | | // Include the implicit "this" pointer as being live. |
233 | 6.13k | CXXMemberCallExpr *CE = cast<CXXMemberCallExpr>(S); |
234 | 6.13k | if (Expr *ImplicitObj = CE->getImplicitObjectArgument()) { |
235 | 6.13k | AddLiveExpr(val.liveExprs, LV.ESetFact, ImplicitObj); |
236 | 6.13k | } |
237 | 6.13k | break; |
238 | 0 | } |
239 | 4.12k | case Stmt::ObjCMessageExprClass: { |
240 | | // In calls to super, include the implicit "self" pointer as being live. |
241 | 4.12k | ObjCMessageExpr *CE = cast<ObjCMessageExpr>(S); |
242 | 4.12k | if (CE->getReceiverKind() == ObjCMessageExpr::SuperInstance) |
243 | 319 | val.liveDecls = LV.DSetFact.add(val.liveDecls, |
244 | 319 | LV.analysisContext.getSelfDecl()); |
245 | 4.12k | break; |
246 | 0 | } |
247 | 22.6k | case Stmt::DeclStmtClass: { |
248 | 22.6k | const DeclStmt *DS = cast<DeclStmt>(S); |
249 | 22.6k | if (const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl())) { |
250 | 22.6k | for (const VariableArrayType* VA = FindVA(VD->getType()); |
251 | 22.7k | VA != nullptr; VA = FindVA(VA->getElementType())64 ) { |
252 | 64 | AddLiveExpr(val.liveExprs, LV.ESetFact, VA->getSizeExpr()); |
253 | 64 | } |
254 | 22.6k | } |
255 | 22.6k | break; |
256 | 0 | } |
257 | 388 | case Stmt::PseudoObjectExprClass: { |
258 | | // A pseudo-object operation only directly consumes its result |
259 | | // expression. |
260 | 388 | Expr *child = cast<PseudoObjectExpr>(S)->getResultExpr(); |
261 | 388 | if (!child) return0 ; |
262 | 388 | if (OpaqueValueExpr *OV = dyn_cast<OpaqueValueExpr>(child)) |
263 | 80 | child = OV->getSourceExpr(); |
264 | 388 | child = child->IgnoreParens(); |
265 | 388 | val.liveExprs = LV.ESetFact.add(val.liveExprs, child); |
266 | 388 | return; |
267 | 388 | } |
268 | | |
269 | | // FIXME: These cases eventually shouldn't be needed. |
270 | 0 | case Stmt::ExprWithCleanupsClass: { |
271 | 0 | S = cast<ExprWithCleanups>(S)->getSubExpr(); |
272 | 0 | break; |
273 | 388 | } |
274 | 1.74k | case Stmt::CXXBindTemporaryExprClass: { |
275 | 1.74k | S = cast<CXXBindTemporaryExpr>(S)->getSubExpr(); |
276 | 1.74k | break; |
277 | 388 | } |
278 | 875 | case Stmt::UnaryExprOrTypeTraitExprClass: { |
279 | | // No need to unconditionally visit subexpressions. |
280 | 875 | return; |
281 | 388 | } |
282 | 5.29k | case Stmt::IfStmtClass: { |
283 | | // If one of the branches is an expression rather than a compound |
284 | | // statement, it will be bad if we mark it as live at the terminator |
285 | | // of the if-statement (i.e., immediately after the condition expression). |
286 | 5.29k | AddLiveExpr(val.liveExprs, LV.ESetFact, cast<IfStmt>(S)->getCond()); |
287 | 5.29k | return; |
288 | 388 | } |
289 | 339 | case Stmt::WhileStmtClass: { |
290 | | // If the loop body is an expression rather than a compound statement, |
291 | | // it will be bad if we mark it as live at the terminator of the loop |
292 | | // (i.e., immediately after the condition expression). |
293 | 339 | AddLiveExpr(val.liveExprs, LV.ESetFact, cast<WhileStmt>(S)->getCond()); |
294 | 339 | return; |
295 | 388 | } |
296 | 178 | case Stmt::DoStmtClass: { |
297 | | // If the loop body is an expression rather than a compound statement, |
298 | | // it will be bad if we mark it as live at the terminator of the loop |
299 | | // (i.e., immediately after the condition expression). |
300 | 178 | AddLiveExpr(val.liveExprs, LV.ESetFact, cast<DoStmt>(S)->getCond()); |
301 | 178 | return; |
302 | 388 | } |
303 | 742 | case Stmt::ForStmtClass: { |
304 | | // If the loop body is an expression rather than a compound statement, |
305 | | // it will be bad if we mark it as live at the terminator of the loop |
306 | | // (i.e., immediately after the condition expression). |
307 | 742 | AddLiveExpr(val.liveExprs, LV.ESetFact, cast<ForStmt>(S)->getCond()); |
308 | 742 | return; |
309 | 388 | } |
310 | | |
311 | 501k | } |
312 | | |
313 | | // HACK + FIXME: What is this? One could only guess that this is an attempt to |
314 | | // fish for live values, for example, arguments from a call expression. |
315 | | // Maybe we could take inspiration from UninitializedVariable analysis? |
316 | 493k | for (Stmt *Child : S->children()) { |
317 | 411k | if (const auto *E = dyn_cast_or_null<Expr>(Child)) |
318 | 410k | AddLiveExpr(val.liveExprs, LV.ESetFact, E); |
319 | 411k | } |
320 | 493k | } |
321 | | |
322 | 553 | static bool writeShouldKill(const VarDecl *VD) { |
323 | 553 | return VD && !VD->getType()->isReferenceType() && |
324 | 553 | !isAlwaysAlive(VD)541 ; |
325 | 553 | } |
326 | | |
327 | 26.3k | void TransferFunctions::VisitBinaryOperator(BinaryOperator *B) { |
328 | 26.3k | if (LV.killAtAssign && B->getOpcode() == BO_Assign1.77k ) { |
329 | 804 | if (const auto *DR = dyn_cast<DeclRefExpr>(B->getLHS()->IgnoreParens())) { |
330 | 515 | LV.inAssignment[DR] = 1; |
331 | 515 | } |
332 | 804 | } |
333 | 26.3k | if (B->isAssignmentOp()) { |
334 | 8.73k | if (!LV.killAtAssign) |
335 | 7.86k | return; |
336 | | |
337 | | // Assigning to a variable? |
338 | 872 | Expr *LHS = B->getLHS()->IgnoreParens(); |
339 | | |
340 | 872 | if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { |
341 | 567 | const Decl* D = DR->getDecl(); |
342 | 567 | bool Killed = false; |
343 | | |
344 | 567 | if (const BindingDecl* BD = dyn_cast<BindingDecl>(D)) { |
345 | 14 | Killed = !BD->getType()->isReferenceType(); |
346 | 14 | if (Killed) |
347 | 14 | val.liveBindings = LV.BSetFact.remove(val.liveBindings, BD); |
348 | 553 | } else if (const auto *VD = dyn_cast<VarDecl>(D)) { |
349 | 553 | Killed = writeShouldKill(VD); |
350 | 553 | if (Killed) |
351 | 525 | val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); |
352 | | |
353 | 553 | } |
354 | | |
355 | 567 | if (Killed && observer539 ) |
356 | 252 | observer->observerKill(DR); |
357 | 567 | } |
358 | 872 | } |
359 | 26.3k | } |
360 | | |
361 | 430 | void TransferFunctions::VisitBlockExpr(BlockExpr *BE) { |
362 | 430 | for (const VarDecl *VD : |
363 | 430 | LV.analysisContext.getReferencedBlockVars(BE->getBlockDecl())) { |
364 | 370 | if (isAlwaysAlive(VD)) |
365 | 44 | continue; |
366 | 326 | val.liveDecls = LV.DSetFact.add(val.liveDecls, VD); |
367 | 326 | } |
368 | 430 | } |
369 | | |
370 | 116k | void TransferFunctions::VisitDeclRefExpr(DeclRefExpr *DR) { |
371 | 116k | const Decl* D = DR->getDecl(); |
372 | 116k | bool InAssignment = LV.inAssignment[DR]; |
373 | 116k | if (const auto *BD = dyn_cast<BindingDecl>(D)) { |
374 | 149 | if (!InAssignment) |
375 | 135 | val.liveBindings = LV.BSetFact.add(val.liveBindings, BD); |
376 | 115k | } else if (const auto *VD = dyn_cast<VarDecl>(D)) { |
377 | 73.7k | if (!InAssignment && !isAlwaysAlive(VD)73.2k ) |
378 | 70.5k | val.liveDecls = LV.DSetFact.add(val.liveDecls, VD); |
379 | 73.7k | } |
380 | 116k | } |
381 | | |
382 | 22.6k | void TransferFunctions::VisitDeclStmt(DeclStmt *DS) { |
383 | 22.6k | for (const auto *DI : DS->decls()) { |
384 | 22.6k | if (const auto *DD = dyn_cast<DecompositionDecl>(DI)) { |
385 | 73 | for (const auto *BD : DD->bindings()) |
386 | 163 | val.liveBindings = LV.BSetFact.remove(val.liveBindings, BD); |
387 | 22.5k | } else if (const auto *VD = dyn_cast<VarDecl>(DI)) { |
388 | 22.5k | if (!isAlwaysAlive(VD)) |
389 | 22.0k | val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); |
390 | 22.5k | } |
391 | 22.6k | } |
392 | 22.6k | } |
393 | | |
394 | 254 | void TransferFunctions::VisitObjCForCollectionStmt(ObjCForCollectionStmt *OS) { |
395 | | // Kill the iteration variable. |
396 | 254 | DeclRefExpr *DR = nullptr; |
397 | 254 | const VarDecl *VD = nullptr; |
398 | | |
399 | 254 | Stmt *element = OS->getElement(); |
400 | 254 | if (DeclStmt *DS = dyn_cast<DeclStmt>(element)) { |
401 | 216 | VD = cast<VarDecl>(DS->getSingleDecl()); |
402 | 216 | } |
403 | 38 | else if ((DR = dyn_cast<DeclRefExpr>(cast<Expr>(element)->IgnoreParens()))) { |
404 | 38 | VD = cast<VarDecl>(DR->getDecl()); |
405 | 38 | } |
406 | | |
407 | 254 | if (VD) { |
408 | 254 | val.liveDecls = LV.DSetFact.remove(val.liveDecls, VD); |
409 | 254 | if (observer && DR14 ) |
410 | 2 | observer->observerKill(DR); |
411 | 254 | } |
412 | 254 | } |
413 | | |
414 | | void TransferFunctions:: |
415 | | VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *UE) |
416 | 875 | { |
417 | | // While sizeof(var) doesn't technically extend the liveness of 'var', it |
418 | | // does extent the liveness of metadata if 'var' is a VariableArrayType. |
419 | | // We handle that special case here. |
420 | 875 | if (UE->getKind() != UETT_SizeOf || UE->isArgumentType()872 ) |
421 | 626 | return; |
422 | | |
423 | 249 | const Expr *subEx = UE->getArgumentExpr(); |
424 | 249 | if (subEx->getType()->isVariableArrayType()) { |
425 | 5 | assert(subEx->isLValue()); |
426 | 0 | val.liveExprs = LV.ESetFact.add(val.liveExprs, subEx->IgnoreParens()); |
427 | 5 | } |
428 | 249 | } |
429 | | |
430 | 12.7k | void TransferFunctions::VisitUnaryOperator(UnaryOperator *UO) { |
431 | | // Treat ++/-- as a kill. |
432 | | // Note we don't actually have to do anything if we don't have an observer, |
433 | | // since a ++/-- acts as both a kill and a "use". |
434 | 12.7k | if (!observer) |
435 | 12.3k | return; |
436 | | |
437 | 373 | switch (UO->getOpcode()) { |
438 | 259 | default: |
439 | 259 | return; |
440 | 259 | case UO_PostInc: |
441 | 19 | case UO_PostDec: |
442 | 112 | case UO_PreInc: |
443 | 114 | case UO_PreDec: |
444 | 114 | break; |
445 | 373 | } |
446 | | |
447 | 114 | if (auto *DR = dyn_cast<DeclRefExpr>(UO->getSubExpr()->IgnoreParens())) { |
448 | 107 | const Decl *D = DR->getDecl(); |
449 | 107 | if (isa<VarDecl>(D) || isa<BindingDecl>(D)0 ) { |
450 | | // Treat ++/-- as a kill. |
451 | 107 | observer->observerKill(DR); |
452 | 107 | } |
453 | 107 | } |
454 | 114 | } |
455 | | |
456 | | LiveVariables::LivenessValues |
457 | | LiveVariablesImpl::runOnBlock(const CFGBlock *block, |
458 | | LiveVariables::LivenessValues val, |
459 | 102k | LiveVariables::Observer *obs) { |
460 | | |
461 | 102k | TransferFunctions TF(*this, val, obs, block); |
462 | | |
463 | | // Visit the terminator (if any). |
464 | 102k | if (const Stmt *term = block->getTerminatorStmt()) |
465 | 9.87k | TF.Visit(const_cast<Stmt*>(term)); |
466 | | |
467 | | // Apply the transfer function for all Stmts in the block. |
468 | 102k | for (CFGBlock::const_reverse_iterator it = block->rbegin(), |
469 | 601k | ei = block->rend(); it != ei; ++it499k ) { |
470 | 499k | const CFGElement &elem = *it; |
471 | | |
472 | 499k | if (Optional<CFGAutomaticObjDtor> Dtor = |
473 | 499k | elem.getAs<CFGAutomaticObjDtor>()) { |
474 | 642 | val.liveDecls = DSetFact.add(val.liveDecls, Dtor->getVarDecl()); |
475 | 642 | continue; |
476 | 642 | } |
477 | | |
478 | 498k | if (!elem.getAs<CFGStmt>()) |
479 | 7.02k | continue; |
480 | | |
481 | 491k | const Stmt *S = elem.castAs<CFGStmt>().getStmt(); |
482 | 491k | TF.Visit(const_cast<Stmt*>(S)); |
483 | 491k | stmtsToLiveness[S] = val; |
484 | 491k | } |
485 | 102k | return val; |
486 | 102k | } |
487 | | |
488 | 519 | void LiveVariables::runOnAllBlocks(LiveVariables::Observer &obs) { |
489 | 519 | const CFG *cfg = getImpl(impl).analysisContext.getCFG(); |
490 | 3.01k | for (CFG::const_iterator it = cfg->begin(), ei = cfg->end(); it != ei; ++it2.49k ) |
491 | 2.49k | getImpl(impl).runOnBlock(*it, getImpl(impl).blocksEndToLiveness[*it], &obs); |
492 | 519 | } |
493 | | |
494 | 27.1k | LiveVariables::LiveVariables(void *im) : impl(im) {} |
495 | | |
496 | 27.1k | LiveVariables::~LiveVariables() { |
497 | 27.1k | delete (LiveVariablesImpl*) impl; |
498 | 27.1k | } |
499 | | |
500 | | std::unique_ptr<LiveVariables> |
501 | 27.1k | LiveVariables::computeLiveness(AnalysisDeclContext &AC, bool killAtAssign) { |
502 | | |
503 | | // No CFG? Bail out. |
504 | 27.1k | CFG *cfg = AC.getCFG(); |
505 | 27.1k | if (!cfg) |
506 | 0 | return nullptr; |
507 | | |
508 | | // The analysis currently has scalability issues for very large CFGs. |
509 | | // Bail out if it looks too large. |
510 | 27.1k | if (cfg->getNumBlockIDs() > 300000) |
511 | 0 | return nullptr; |
512 | | |
513 | 27.1k | LiveVariablesImpl *LV = new LiveVariablesImpl(AC, killAtAssign); |
514 | | |
515 | | // Construct the dataflow worklist. Enqueue the exit block as the |
516 | | // start of the analysis. |
517 | 27.1k | BackwardDataflowWorklist worklist(*cfg, AC); |
518 | 27.1k | llvm::BitVector everAnalyzedBlock(cfg->getNumBlockIDs()); |
519 | | |
520 | | // FIXME: we should enqueue using post order. |
521 | 97.3k | for (const CFGBlock *B : cfg->nodes()) { |
522 | 97.3k | worklist.enqueueBlock(B); |
523 | 97.3k | } |
524 | | |
525 | 128k | while (const CFGBlock *block = worklist.dequeue()) { |
526 | | // Determine if the block's end value has changed. If not, we |
527 | | // have nothing left to do for this block. |
528 | 101k | LivenessValues &prevVal = LV->blocksEndToLiveness[block]; |
529 | | |
530 | | // Merge the values of all successor blocks. |
531 | 101k | LivenessValues val; |
532 | 101k | for (CFGBlock::const_succ_iterator it = block->succ_begin(), |
533 | 184k | ei = block->succ_end(); it != ei; ++it83.8k ) { |
534 | 83.8k | if (const CFGBlock *succ = *it) { |
535 | 82.7k | val = LV->merge(val, LV->blocksBeginToLiveness[succ]); |
536 | 82.7k | } |
537 | 83.8k | } |
538 | | |
539 | 101k | if (!everAnalyzedBlock[block->getBlockID()]) |
540 | 97.3k | everAnalyzedBlock[block->getBlockID()] = true; |
541 | 3.62k | else if (prevVal.equals(val)) |
542 | 1.25k | continue; |
543 | | |
544 | 99.7k | prevVal = val; |
545 | | |
546 | | // Update the dataflow value for the start of this block. |
547 | 99.7k | LV->blocksBeginToLiveness[block] = LV->runOnBlock(block, val); |
548 | | |
549 | | // Enqueue the value to the predecessors. |
550 | 99.7k | worklist.enqueuePredecessors(block); |
551 | 99.7k | } |
552 | | |
553 | 27.1k | return std::unique_ptr<LiveVariables>(new LiveVariables(LV)); |
554 | 27.1k | } |
555 | | |
556 | 2 | void LiveVariables::dumpBlockLiveness(const SourceManager &M) { |
557 | 2 | getImpl(impl).dumpBlockLiveness(M); |
558 | 2 | } |
559 | | |
560 | 2 | void LiveVariablesImpl::dumpBlockLiveness(const SourceManager &M) { |
561 | 2 | std::vector<const CFGBlock *> vec; |
562 | 2 | for (llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues>::iterator |
563 | 2 | it = blocksEndToLiveness.begin(), ei = blocksEndToLiveness.end(); |
564 | 8 | it != ei; ++it6 ) { |
565 | 6 | vec.push_back(it->first); |
566 | 6 | } |
567 | 4 | llvm::sort(vec, [](const CFGBlock *A, const CFGBlock *B) { |
568 | 4 | return A->getBlockID() < B->getBlockID(); |
569 | 4 | }); |
570 | | |
571 | 2 | std::vector<const VarDecl*> declVec; |
572 | | |
573 | 2 | for (std::vector<const CFGBlock *>::iterator |
574 | 8 | it = vec.begin(), ei = vec.end(); it != ei; ++it6 ) { |
575 | 6 | llvm::errs() << "\n[ B" << (*it)->getBlockID() |
576 | 6 | << " (live variables at block exit) ]\n"; |
577 | | |
578 | 6 | LiveVariables::LivenessValues vals = blocksEndToLiveness[*it]; |
579 | 6 | declVec.clear(); |
580 | | |
581 | 6 | for (llvm::ImmutableSet<const VarDecl *>::iterator si = |
582 | 6 | vals.liveDecls.begin(), |
583 | 7 | se = vals.liveDecls.end(); si != se; ++si1 ) { |
584 | 1 | declVec.push_back(*si); |
585 | 1 | } |
586 | | |
587 | 6 | llvm::sort(declVec, [](const Decl *A, const Decl *B) { |
588 | 0 | return A->getBeginLoc() < B->getBeginLoc(); |
589 | 0 | }); |
590 | | |
591 | 6 | for (std::vector<const VarDecl*>::iterator di = declVec.begin(), |
592 | 7 | de = declVec.end(); di != de; ++di1 ) { |
593 | 1 | llvm::errs() << " " << (*di)->getDeclName().getAsString() |
594 | 1 | << " <"; |
595 | 1 | (*di)->getLocation().print(llvm::errs(), M); |
596 | 1 | llvm::errs() << ">\n"; |
597 | 1 | } |
598 | 6 | } |
599 | 2 | llvm::errs() << "\n"; |
600 | 2 | } |
601 | | |
602 | 12 | void LiveVariables::dumpExprLiveness(const SourceManager &M) { |
603 | 12 | getImpl(impl).dumpExprLiveness(M); |
604 | 12 | } |
605 | | |
606 | 12 | void LiveVariablesImpl::dumpExprLiveness(const SourceManager &M) { |
607 | | // Don't iterate over blockEndsToLiveness directly because it's not sorted. |
608 | 59 | for (const CFGBlock *B : *analysisContext.getCFG()) { |
609 | | |
610 | 59 | llvm::errs() << "\n[ B" << B->getBlockID() |
611 | 59 | << " (live expressions at block exit) ]\n"; |
612 | 59 | for (const Expr *E : blocksEndToLiveness[B].liveExprs) { |
613 | 14 | llvm::errs() << "\n"; |
614 | 14 | E->dump(); |
615 | 14 | } |
616 | 59 | llvm::errs() << "\n"; |
617 | 59 | } |
618 | 12 | } |
619 | | |
620 | 521 | const void *LiveVariables::getTag() { static int x; return &x; } |
621 | 2.15M | const void *RelaxedLiveVariables::getTag() { static int x; return &x; } |