1 //===- ThreadSafetyCommon.cpp -----------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Implementation of the interfaces declared in ThreadSafetyCommon.h
12 //===----------------------------------------------------------------------===//
14 #include "clang/Analysis/Analyses/ThreadSafetyCommon.h"
15 #include "clang/AST/Attr.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/StmtCXX.h"
20 #include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
21 #include "clang/Analysis/Analyses/ThreadSafetyTraverse.h"
22 #include "clang/Analysis/AnalysisContext.h"
23 #include "clang/Analysis/CFG.h"
24 #include "clang/Basic/OperatorKinds.h"
25 #include "clang/Basic/SourceLocation.h"
26 #include "llvm/ADT/StringRef.h"
29 using namespace clang;
30 using namespace threadSafety;
32 // From ThreadSafetyUtil.h
33 std::string threadSafety::getSourceLiteralString(const clang::Expr *CE) {
34 switch (CE->getStmtClass()) {
35 case Stmt::IntegerLiteralClass:
36 return cast<IntegerLiteral>(CE)->getValue().toString(10, true);
37 case Stmt::StringLiteralClass: {
38 std::string ret("\"");
39 ret += cast<StringLiteral>(CE)->getString();
43 case Stmt::CharacterLiteralClass:
44 case Stmt::CXXNullPtrLiteralExprClass:
45 case Stmt::GNUNullExprClass:
46 case Stmt::CXXBoolLiteralExprClass:
47 case Stmt::FloatingLiteralClass:
48 case Stmt::ImaginaryLiteralClass:
49 case Stmt::ObjCStringLiteralClass:
55 // Return true if E is a variable that points to an incomplete Phi node.
56 static bool isIncompletePhi(const til::SExpr *E) {
57 if (const auto *Ph = dyn_cast<til::Phi>(E))
58 return Ph->status() == til::Phi::PH_Incomplete;
62 typedef SExprBuilder::CallingContext CallingContext;
64 til::SExpr *SExprBuilder::lookupStmt(const Stmt *S) {
65 auto It = SMap.find(S);
71 til::SCFG *SExprBuilder::buildCFG(CFGWalker &Walker) {
76 static bool isCalleeArrow(const Expr *E) {
77 const MemberExpr *ME = dyn_cast<MemberExpr>(E->IgnoreParenCasts());
78 return ME ? ME->isArrow() : false;
81 /// \brief Translate a clang expression in an attribute to a til::SExpr.
82 /// Constructs the context from D, DeclExp, and SelfDecl.
84 /// \param AttrExp The expression to translate.
85 /// \param D The declaration to which the attribute is attached.
86 /// \param DeclExp An expression involving the Decl to which the attribute
87 /// is attached. E.g. the call to a function.
88 CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
92 // If we are processing a raw attribute expression, with no substitutions.
94 return translateAttrExpr(AttrExp, nullptr);
96 CallingContext Ctx(nullptr, D);
98 // Examine DeclExp to find SelfArg and FunArgs, which are used to substitute
99 // for formal parameters when we call buildMutexID later.
100 if (const MemberExpr *ME = dyn_cast<MemberExpr>(DeclExp)) {
101 Ctx.SelfArg = ME->getBase();
102 Ctx.SelfArrow = ME->isArrow();
103 } else if (const CXXMemberCallExpr *CE =
104 dyn_cast<CXXMemberCallExpr>(DeclExp)) {
105 Ctx.SelfArg = CE->getImplicitObjectArgument();
106 Ctx.SelfArrow = isCalleeArrow(CE->getCallee());
107 Ctx.NumArgs = CE->getNumArgs();
108 Ctx.FunArgs = CE->getArgs();
109 } else if (const CallExpr *CE = dyn_cast<CallExpr>(DeclExp)) {
110 Ctx.NumArgs = CE->getNumArgs();
111 Ctx.FunArgs = CE->getArgs();
112 } else if (const CXXConstructExpr *CE =
113 dyn_cast<CXXConstructExpr>(DeclExp)) {
114 Ctx.SelfArg = nullptr; // Will be set below
115 Ctx.NumArgs = CE->getNumArgs();
116 Ctx.FunArgs = CE->getArgs();
117 } else if (D && isa<CXXDestructorDecl>(D)) {
118 // There's no such thing as a "destructor call" in the AST.
119 Ctx.SelfArg = DeclExp;
122 // Hack to handle constructors, where self cannot be recovered from
124 if (SelfDecl && !Ctx.SelfArg) {
125 DeclRefExpr SelfDRE(SelfDecl, false, SelfDecl->getType(), VK_LValue,
126 SelfDecl->getLocation());
127 Ctx.SelfArg = &SelfDRE;
129 // If the attribute has no arguments, then assume the argument is "this".
131 return translateAttrExpr(Ctx.SelfArg, nullptr);
132 else // For most attributes.
133 return translateAttrExpr(AttrExp, &Ctx);
136 // If the attribute has no arguments, then assume the argument is "this".
138 return translateAttrExpr(Ctx.SelfArg, nullptr);
139 else // For most attributes.
140 return translateAttrExpr(AttrExp, &Ctx);
143 /// \brief Translate a clang expression in an attribute to a til::SExpr.
144 // This assumes a CallingContext has already been created.
145 CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
146 CallingContext *Ctx) {
148 return CapabilityExpr(nullptr, false);
150 if (auto* SLit = dyn_cast<StringLiteral>(AttrExp)) {
151 if (SLit->getString() == StringRef("*"))
152 // The "*" expr is a universal lock, which essentially turns off
153 // checks until it is removed from the lockset.
154 return CapabilityExpr(new (Arena) til::Wildcard(), false);
156 // Ignore other string literals for now.
157 return CapabilityExpr(nullptr, false);
161 if (auto *OE = dyn_cast<CXXOperatorCallExpr>(AttrExp)) {
162 if (OE->getOperator() == OO_Exclaim) {
164 AttrExp = OE->getArg(0);
167 else if (auto *UO = dyn_cast<UnaryOperator>(AttrExp)) {
168 if (UO->getOpcode() == UO_LNot) {
170 AttrExp = UO->getSubExpr();
174 til::SExpr *E = translate(AttrExp, Ctx);
176 // Trap mutex expressions like nullptr, or 0.
177 // Any literal value is nonsense.
178 if (!E || isa<til::Literal>(E))
179 return CapabilityExpr(nullptr, false);
181 // Hack to deal with smart pointers -- strip off top-level pointer casts.
182 if (auto *CE = dyn_cast_or_null<til::Cast>(E)) {
183 if (CE->castOpcode() == til::CAST_objToPtr)
184 return CapabilityExpr(CE->expr(), Neg);
186 return CapabilityExpr(E, Neg);
189 // Translate a clang statement or expression to a TIL expression.
190 // Also performs substitution of variables; Ctx provides the context.
191 // Dispatches on the type of S.
192 til::SExpr *SExprBuilder::translate(const Stmt *S, CallingContext *Ctx) {
196 // Check if S has already been translated and cached.
197 // This handles the lookup of SSA names for DeclRefExprs here.
198 if (til::SExpr *E = lookupStmt(S))
201 switch (S->getStmtClass()) {
202 case Stmt::DeclRefExprClass:
203 return translateDeclRefExpr(cast<DeclRefExpr>(S), Ctx);
204 case Stmt::CXXThisExprClass:
205 return translateCXXThisExpr(cast<CXXThisExpr>(S), Ctx);
206 case Stmt::MemberExprClass:
207 return translateMemberExpr(cast<MemberExpr>(S), Ctx);
208 case Stmt::CallExprClass:
209 return translateCallExpr(cast<CallExpr>(S), Ctx);
210 case Stmt::CXXMemberCallExprClass:
211 return translateCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), Ctx);
212 case Stmt::CXXOperatorCallExprClass:
213 return translateCXXOperatorCallExpr(cast<CXXOperatorCallExpr>(S), Ctx);
214 case Stmt::UnaryOperatorClass:
215 return translateUnaryOperator(cast<UnaryOperator>(S), Ctx);
216 case Stmt::BinaryOperatorClass:
217 case Stmt::CompoundAssignOperatorClass:
218 return translateBinaryOperator(cast<BinaryOperator>(S), Ctx);
220 case Stmt::ArraySubscriptExprClass:
221 return translateArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Ctx);
222 case Stmt::ConditionalOperatorClass:
223 return translateAbstractConditionalOperator(
224 cast<ConditionalOperator>(S), Ctx);
225 case Stmt::BinaryConditionalOperatorClass:
226 return translateAbstractConditionalOperator(
227 cast<BinaryConditionalOperator>(S), Ctx);
229 // We treat these as no-ops
230 case Stmt::ParenExprClass:
231 return translate(cast<ParenExpr>(S)->getSubExpr(), Ctx);
232 case Stmt::ExprWithCleanupsClass:
233 return translate(cast<ExprWithCleanups>(S)->getSubExpr(), Ctx);
234 case Stmt::CXXBindTemporaryExprClass:
235 return translate(cast<CXXBindTemporaryExpr>(S)->getSubExpr(), Ctx);
236 case Stmt::MaterializeTemporaryExprClass:
237 return translate(cast<MaterializeTemporaryExpr>(S)->GetTemporaryExpr(),
240 // Collect all literals
241 case Stmt::CharacterLiteralClass:
242 case Stmt::CXXNullPtrLiteralExprClass:
243 case Stmt::GNUNullExprClass:
244 case Stmt::CXXBoolLiteralExprClass:
245 case Stmt::FloatingLiteralClass:
246 case Stmt::ImaginaryLiteralClass:
247 case Stmt::IntegerLiteralClass:
248 case Stmt::StringLiteralClass:
249 case Stmt::ObjCStringLiteralClass:
250 return new (Arena) til::Literal(cast<Expr>(S));
252 case Stmt::DeclStmtClass:
253 return translateDeclStmt(cast<DeclStmt>(S), Ctx);
257 if (const CastExpr *CE = dyn_cast<CastExpr>(S))
258 return translateCastExpr(CE, Ctx);
260 return new (Arena) til::Undefined(S);
263 til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
264 CallingContext *Ctx) {
265 const ValueDecl *VD = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
267 // Function parameters require substitution and/or renaming.
268 if (const ParmVarDecl *PV = dyn_cast_or_null<ParmVarDecl>(VD)) {
269 const FunctionDecl *FD =
270 cast<FunctionDecl>(PV->getDeclContext())->getCanonicalDecl();
271 unsigned I = PV->getFunctionScopeIndex();
273 if (Ctx && Ctx->FunArgs && FD == Ctx->AttrDecl->getCanonicalDecl()) {
274 // Substitute call arguments for references to function parameters
275 assert(I < Ctx->NumArgs);
276 return translate(Ctx->FunArgs[I], Ctx->Prev);
278 // Map the param back to the param of the original function declaration
279 // for consistent comparisons.
280 VD = FD->getParamDecl(I);
283 // For non-local variables, treat it as a reference to a named object.
284 return new (Arena) til::LiteralPtr(VD);
287 til::SExpr *SExprBuilder::translateCXXThisExpr(const CXXThisExpr *TE,
288 CallingContext *Ctx) {
289 // Substitute for 'this'
290 if (Ctx && Ctx->SelfArg)
291 return translate(Ctx->SelfArg, Ctx->Prev);
292 assert(SelfVar && "We have no variable for 'this'!");
296 static const ValueDecl *getValueDeclFromSExpr(const til::SExpr *E) {
297 if (auto *V = dyn_cast<til::Variable>(E))
298 return V->clangDecl();
299 if (auto *Ph = dyn_cast<til::Phi>(E))
300 return Ph->clangDecl();
301 if (auto *P = dyn_cast<til::Project>(E))
302 return P->clangDecl();
303 if (auto *L = dyn_cast<til::LiteralPtr>(E))
304 return L->clangDecl();
308 static bool hasCppPointerType(const til::SExpr *E) {
309 auto *VD = getValueDeclFromSExpr(E);
310 if (VD && VD->getType()->isPointerType())
312 if (auto *C = dyn_cast<til::Cast>(E))
313 return C->castOpcode() == til::CAST_objToPtr;
318 // Grab the very first declaration of virtual method D
319 static const CXXMethodDecl *getFirstVirtualDecl(const CXXMethodDecl *D) {
321 D = D->getCanonicalDecl();
322 CXXMethodDecl::method_iterator I = D->begin_overridden_methods(),
323 E = D->end_overridden_methods();
325 return D; // Method does not override anything
326 D = *I; // FIXME: this does not work with multiple inheritance.
331 til::SExpr *SExprBuilder::translateMemberExpr(const MemberExpr *ME,
332 CallingContext *Ctx) {
333 til::SExpr *BE = translate(ME->getBase(), Ctx);
334 til::SExpr *E = new (Arena) til::SApply(BE);
337 cast<ValueDecl>(ME->getMemberDecl()->getCanonicalDecl());
338 if (auto *VD = dyn_cast<CXXMethodDecl>(D))
339 D = getFirstVirtualDecl(VD);
341 til::Project *P = new (Arena) til::Project(E, D);
342 if (hasCppPointerType(BE))
347 til::SExpr *SExprBuilder::translateCallExpr(const CallExpr *CE,
350 if (CapabilityExprMode) {
351 // Handle LOCK_RETURNED
352 const FunctionDecl *FD = CE->getDirectCallee()->getMostRecentDecl();
353 if (LockReturnedAttr* At = FD->getAttr<LockReturnedAttr>()) {
354 CallingContext LRCallCtx(Ctx);
355 LRCallCtx.AttrDecl = CE->getDirectCallee();
356 LRCallCtx.SelfArg = SelfE;
357 LRCallCtx.NumArgs = CE->getNumArgs();
358 LRCallCtx.FunArgs = CE->getArgs();
359 return const_cast<til::SExpr*>(
360 translateAttrExpr(At->getArg(), &LRCallCtx).sexpr());
364 til::SExpr *E = translate(CE->getCallee(), Ctx);
365 for (const auto *Arg : CE->arguments()) {
366 til::SExpr *A = translate(Arg, Ctx);
367 E = new (Arena) til::Apply(E, A);
369 return new (Arena) til::Call(E, CE);
372 til::SExpr *SExprBuilder::translateCXXMemberCallExpr(
373 const CXXMemberCallExpr *ME, CallingContext *Ctx) {
374 if (CapabilityExprMode) {
375 // Ignore calls to get() on smart pointers.
376 if (ME->getMethodDecl()->getNameAsString() == "get" &&
377 ME->getNumArgs() == 0) {
378 auto *E = translate(ME->getImplicitObjectArgument(), Ctx);
379 return new (Arena) til::Cast(til::CAST_objToPtr, E);
383 return translateCallExpr(cast<CallExpr>(ME), Ctx,
384 ME->getImplicitObjectArgument());
387 til::SExpr *SExprBuilder::translateCXXOperatorCallExpr(
388 const CXXOperatorCallExpr *OCE, CallingContext *Ctx) {
389 if (CapabilityExprMode) {
390 // Ignore operator * and operator -> on smart pointers.
391 OverloadedOperatorKind k = OCE->getOperator();
392 if (k == OO_Star || k == OO_Arrow) {
393 auto *E = translate(OCE->getArg(0), Ctx);
394 return new (Arena) til::Cast(til::CAST_objToPtr, E);
398 return translateCallExpr(cast<CallExpr>(OCE), Ctx);
401 til::SExpr *SExprBuilder::translateUnaryOperator(const UnaryOperator *UO,
402 CallingContext *Ctx) {
403 switch (UO->getOpcode()) {
408 return new (Arena) til::Undefined(UO);
411 if (CapabilityExprMode) {
412 // interpret &Graph::mu_ as an existential.
413 if (DeclRefExpr* DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr())) {
414 if (DRE->getDecl()->isCXXInstanceMember()) {
415 // This is a pointer-to-member expression, e.g. &MyClass::mu_.
416 // We interpret this syntax specially, as a wildcard.
417 auto *W = new (Arena) til::Wildcard();
418 return new (Arena) til::Project(W, DRE->getDecl());
422 // otherwise, & is a no-op
423 return translate(UO->getSubExpr(), Ctx);
426 // We treat these as no-ops
429 return translate(UO->getSubExpr(), Ctx);
433 til::UnaryOp(til::UOP_Minus, translate(UO->getSubExpr(), Ctx));
436 til::UnaryOp(til::UOP_BitNot, translate(UO->getSubExpr(), Ctx));
439 til::UnaryOp(til::UOP_LogicNot, translate(UO->getSubExpr(), Ctx));
441 // Currently unsupported
446 return new (Arena) til::Undefined(UO);
448 return new (Arena) til::Undefined(UO);
451 til::SExpr *SExprBuilder::translateBinOp(til::TIL_BinaryOpcode Op,
452 const BinaryOperator *BO,
453 CallingContext *Ctx, bool Reverse) {
454 til::SExpr *E0 = translate(BO->getLHS(), Ctx);
455 til::SExpr *E1 = translate(BO->getRHS(), Ctx);
457 return new (Arena) til::BinaryOp(Op, E1, E0);
459 return new (Arena) til::BinaryOp(Op, E0, E1);
462 til::SExpr *SExprBuilder::translateBinAssign(til::TIL_BinaryOpcode Op,
463 const BinaryOperator *BO,
466 const Expr *LHS = BO->getLHS();
467 const Expr *RHS = BO->getRHS();
468 til::SExpr *E0 = translate(LHS, Ctx);
469 til::SExpr *E1 = translate(RHS, Ctx);
471 const ValueDecl *VD = nullptr;
472 til::SExpr *CV = nullptr;
473 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(LHS)) {
475 CV = lookupVarDecl(VD);
479 til::SExpr *Arg = CV ? CV : new (Arena) til::Load(E0);
480 E1 = new (Arena) til::BinaryOp(Op, Arg, E1);
481 E1 = addStatement(E1, nullptr, VD);
484 return updateVarDecl(VD, E1);
485 return new (Arena) til::Store(E0, E1);
488 til::SExpr *SExprBuilder::translateBinaryOperator(const BinaryOperator *BO,
489 CallingContext *Ctx) {
490 switch (BO->getOpcode()) {
493 return new (Arena) til::Undefined(BO);
495 case BO_Mul: return translateBinOp(til::BOP_Mul, BO, Ctx);
496 case BO_Div: return translateBinOp(til::BOP_Div, BO, Ctx);
497 case BO_Rem: return translateBinOp(til::BOP_Rem, BO, Ctx);
498 case BO_Add: return translateBinOp(til::BOP_Add, BO, Ctx);
499 case BO_Sub: return translateBinOp(til::BOP_Sub, BO, Ctx);
500 case BO_Shl: return translateBinOp(til::BOP_Shl, BO, Ctx);
501 case BO_Shr: return translateBinOp(til::BOP_Shr, BO, Ctx);
502 case BO_LT: return translateBinOp(til::BOP_Lt, BO, Ctx);
503 case BO_GT: return translateBinOp(til::BOP_Lt, BO, Ctx, true);
504 case BO_LE: return translateBinOp(til::BOP_Leq, BO, Ctx);
505 case BO_GE: return translateBinOp(til::BOP_Leq, BO, Ctx, true);
506 case BO_EQ: return translateBinOp(til::BOP_Eq, BO, Ctx);
507 case BO_NE: return translateBinOp(til::BOP_Neq, BO, Ctx);
508 case BO_And: return translateBinOp(til::BOP_BitAnd, BO, Ctx);
509 case BO_Xor: return translateBinOp(til::BOP_BitXor, BO, Ctx);
510 case BO_Or: return translateBinOp(til::BOP_BitOr, BO, Ctx);
511 case BO_LAnd: return translateBinOp(til::BOP_LogicAnd, BO, Ctx);
512 case BO_LOr: return translateBinOp(til::BOP_LogicOr, BO, Ctx);
514 case BO_Assign: return translateBinAssign(til::BOP_Eq, BO, Ctx, true);
515 case BO_MulAssign: return translateBinAssign(til::BOP_Mul, BO, Ctx);
516 case BO_DivAssign: return translateBinAssign(til::BOP_Div, BO, Ctx);
517 case BO_RemAssign: return translateBinAssign(til::BOP_Rem, BO, Ctx);
518 case BO_AddAssign: return translateBinAssign(til::BOP_Add, BO, Ctx);
519 case BO_SubAssign: return translateBinAssign(til::BOP_Sub, BO, Ctx);
520 case BO_ShlAssign: return translateBinAssign(til::BOP_Shl, BO, Ctx);
521 case BO_ShrAssign: return translateBinAssign(til::BOP_Shr, BO, Ctx);
522 case BO_AndAssign: return translateBinAssign(til::BOP_BitAnd, BO, Ctx);
523 case BO_XorAssign: return translateBinAssign(til::BOP_BitXor, BO, Ctx);
524 case BO_OrAssign: return translateBinAssign(til::BOP_BitOr, BO, Ctx);
527 // The clang CFG should have already processed both sides.
528 return translate(BO->getRHS(), Ctx);
530 return new (Arena) til::Undefined(BO);
533 til::SExpr *SExprBuilder::translateCastExpr(const CastExpr *CE,
534 CallingContext *Ctx) {
535 clang::CastKind K = CE->getCastKind();
537 case CK_LValueToRValue: {
538 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
539 til::SExpr *E0 = lookupVarDecl(DRE->getDecl());
543 til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
545 // FIXME!! -- get Load working properly
546 // return new (Arena) til::Load(E0);
549 case CK_DerivedToBase:
550 case CK_UncheckedDerivedToBase:
551 case CK_ArrayToPointerDecay:
552 case CK_FunctionToPointerDecay: {
553 til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
557 // FIXME: handle different kinds of casts.
558 til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
559 if (CapabilityExprMode)
561 return new (Arena) til::Cast(til::CAST_none, E0);
567 SExprBuilder::translateArraySubscriptExpr(const ArraySubscriptExpr *E,
568 CallingContext *Ctx) {
569 til::SExpr *E0 = translate(E->getBase(), Ctx);
570 til::SExpr *E1 = translate(E->getIdx(), Ctx);
571 return new (Arena) til::ArrayIndex(E0, E1);
575 SExprBuilder::translateAbstractConditionalOperator(
576 const AbstractConditionalOperator *CO, CallingContext *Ctx) {
577 auto *C = translate(CO->getCond(), Ctx);
578 auto *T = translate(CO->getTrueExpr(), Ctx);
579 auto *E = translate(CO->getFalseExpr(), Ctx);
580 return new (Arena) til::IfThenElse(C, T, E);
584 SExprBuilder::translateDeclStmt(const DeclStmt *S, CallingContext *Ctx) {
585 DeclGroupRef DGrp = S->getDeclGroup();
586 for (DeclGroupRef::iterator I = DGrp.begin(), E = DGrp.end(); I != E; ++I) {
587 if (VarDecl *VD = dyn_cast_or_null<VarDecl>(*I)) {
588 Expr *E = VD->getInit();
589 til::SExpr* SE = translate(E, Ctx);
591 // Add local variables with trivial type to the variable map
592 QualType T = VD->getType();
593 if (T.isTrivialType(VD->getASTContext())) {
594 return addVarDecl(VD, SE);
604 // If (E) is non-trivial, then add it to the current basic block, and
605 // update the statement map so that S refers to E. Returns a new variable
607 // If E is trivial returns E.
608 til::SExpr *SExprBuilder::addStatement(til::SExpr* E, const Stmt *S,
609 const ValueDecl *VD) {
610 if (!E || !CurrentBB || E->block() || til::ThreadSafetyTIL::isTrivial(E))
613 E = new (Arena) til::Variable(E, VD);
614 CurrentInstructions.push_back(E);
620 // Returns the current value of VD, if known, and nullptr otherwise.
621 til::SExpr *SExprBuilder::lookupVarDecl(const ValueDecl *VD) {
622 auto It = LVarIdxMap.find(VD);
623 if (It != LVarIdxMap.end()) {
624 assert(CurrentLVarMap[It->second].first == VD);
625 return CurrentLVarMap[It->second].second;
630 // if E is a til::Variable, update its clangDecl.
631 static void maybeUpdateVD(til::SExpr *E, const ValueDecl *VD) {
634 if (til::Variable *V = dyn_cast<til::Variable>(E)) {
640 // Adds a new variable declaration.
641 til::SExpr *SExprBuilder::addVarDecl(const ValueDecl *VD, til::SExpr *E) {
642 maybeUpdateVD(E, VD);
643 LVarIdxMap.insert(std::make_pair(VD, CurrentLVarMap.size()));
644 CurrentLVarMap.makeWritable();
645 CurrentLVarMap.push_back(std::make_pair(VD, E));
649 // Updates a current variable declaration. (E.g. by assignment)
650 til::SExpr *SExprBuilder::updateVarDecl(const ValueDecl *VD, til::SExpr *E) {
651 maybeUpdateVD(E, VD);
652 auto It = LVarIdxMap.find(VD);
653 if (It == LVarIdxMap.end()) {
654 til::SExpr *Ptr = new (Arena) til::LiteralPtr(VD);
655 til::SExpr *St = new (Arena) til::Store(Ptr, E);
658 CurrentLVarMap.makeWritable();
659 CurrentLVarMap.elem(It->second).second = E;
663 // Make a Phi node in the current block for the i^th variable in CurrentVarMap.
664 // If E != null, sets Phi[CurrentBlockInfo->ArgIndex] = E.
665 // If E == null, this is a backedge and will be set later.
666 void SExprBuilder::makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E) {
667 unsigned ArgIndex = CurrentBlockInfo->ProcessedPredecessors;
668 assert(ArgIndex > 0 && ArgIndex < NPreds);
670 til::SExpr *CurrE = CurrentLVarMap[i].second;
671 if (CurrE->block() == CurrentBB) {
672 // We already have a Phi node in the current block,
673 // so just add the new variable to the Phi node.
674 til::Phi *Ph = dyn_cast<til::Phi>(CurrE);
675 assert(Ph && "Expecting Phi node.");
677 Ph->values()[ArgIndex] = E;
681 // Make a new phi node: phi(..., E)
682 // All phi args up to the current index are set to the current value.
683 til::Phi *Ph = new (Arena) til::Phi(Arena, NPreds);
684 Ph->values().setValues(NPreds, nullptr);
685 for (unsigned PIdx = 0; PIdx < ArgIndex; ++PIdx)
686 Ph->values()[PIdx] = CurrE;
688 Ph->values()[ArgIndex] = E;
689 Ph->setClangDecl(CurrentLVarMap[i].first);
690 // If E is from a back-edge, or either E or CurrE are incomplete, then
691 // mark this node as incomplete; we may need to remove it later.
692 if (!E || isIncompletePhi(E) || isIncompletePhi(CurrE)) {
693 Ph->setStatus(til::Phi::PH_Incomplete);
696 // Add Phi node to current block, and update CurrentLVarMap[i]
697 CurrentArguments.push_back(Ph);
698 if (Ph->status() == til::Phi::PH_Incomplete)
699 IncompleteArgs.push_back(Ph);
701 CurrentLVarMap.makeWritable();
702 CurrentLVarMap.elem(i).second = Ph;
705 // Merge values from Map into the current variable map.
706 // This will construct Phi nodes in the current basic block as necessary.
707 void SExprBuilder::mergeEntryMap(LVarDefinitionMap Map) {
708 assert(CurrentBlockInfo && "Not processing a block!");
710 if (!CurrentLVarMap.valid()) {
711 // Steal Map, using copy-on-write.
712 CurrentLVarMap = std::move(Map);
715 if (CurrentLVarMap.sameAs(Map))
716 return; // Easy merge: maps from different predecessors are unchanged.
718 unsigned NPreds = CurrentBB->numPredecessors();
719 unsigned ESz = CurrentLVarMap.size();
720 unsigned MSz = Map.size();
721 unsigned Sz = std::min(ESz, MSz);
723 for (unsigned i=0; i<Sz; ++i) {
724 if (CurrentLVarMap[i].first != Map[i].first) {
725 // We've reached the end of variables in common.
726 CurrentLVarMap.makeWritable();
727 CurrentLVarMap.downsize(i);
730 if (CurrentLVarMap[i].second != Map[i].second)
731 makePhiNodeVar(i, NPreds, Map[i].second);
734 CurrentLVarMap.makeWritable();
735 CurrentLVarMap.downsize(Map.size());
739 // Merge a back edge into the current variable map.
740 // This will create phi nodes for all variables in the variable map.
741 void SExprBuilder::mergeEntryMapBackEdge() {
742 // We don't have definitions for variables on the backedge, because we
743 // haven't gotten that far in the CFG. Thus, when encountering a back edge,
744 // we conservatively create Phi nodes for all variables. Unnecessary Phi
745 // nodes will be marked as incomplete, and stripped out at the end.
747 // An Phi node is unnecessary if it only refers to itself and one other
748 // variable, e.g. x = Phi(y, y, x) can be reduced to x = y.
750 assert(CurrentBlockInfo && "Not processing a block!");
752 if (CurrentBlockInfo->HasBackEdges)
754 CurrentBlockInfo->HasBackEdges = true;
756 CurrentLVarMap.makeWritable();
757 unsigned Sz = CurrentLVarMap.size();
758 unsigned NPreds = CurrentBB->numPredecessors();
760 for (unsigned i=0; i < Sz; ++i) {
761 makePhiNodeVar(i, NPreds, nullptr);
765 // Update the phi nodes that were initially created for a back edge
766 // once the variable definitions have been computed.
767 // I.e., merge the current variable map into the phi nodes for Blk.
768 void SExprBuilder::mergePhiNodesBackEdge(const CFGBlock *Blk) {
769 til::BasicBlock *BB = lookupBlock(Blk);
770 unsigned ArgIndex = BBInfo[Blk->getBlockID()].ProcessedPredecessors;
771 assert(ArgIndex > 0 && ArgIndex < BB->numPredecessors());
773 for (til::SExpr *PE : BB->arguments()) {
774 til::Phi *Ph = dyn_cast_or_null<til::Phi>(PE);
775 assert(Ph && "Expecting Phi Node.");
776 assert(Ph->values()[ArgIndex] == nullptr && "Wrong index for back edge.");
778 til::SExpr *E = lookupVarDecl(Ph->clangDecl());
779 assert(E && "Couldn't find local variable for Phi node.");
780 Ph->values()[ArgIndex] = E;
784 void SExprBuilder::enterCFG(CFG *Cfg, const NamedDecl *D,
785 const CFGBlock *First) {
786 // Perform initial setup operations.
787 unsigned NBlocks = Cfg->getNumBlockIDs();
788 Scfg = new (Arena) til::SCFG(Arena, NBlocks);
790 // allocate all basic blocks immediately, to handle forward references.
791 BBInfo.resize(NBlocks);
792 BlockMap.resize(NBlocks, nullptr);
793 // create map from clang blockID to til::BasicBlocks
794 for (auto *B : *Cfg) {
795 auto *BB = new (Arena) til::BasicBlock(Arena);
796 BB->reserveInstructions(B->size());
797 BlockMap[B->getBlockID()] = BB;
800 CurrentBB = lookupBlock(&Cfg->getEntry());
801 auto Parms = isa<ObjCMethodDecl>(D) ? cast<ObjCMethodDecl>(D)->parameters()
802 : cast<FunctionDecl>(D)->parameters();
803 for (auto *Pm : Parms) {
804 QualType T = Pm->getType();
805 if (!T.isTrivialType(Pm->getASTContext()))
808 // Add parameters to local variable map.
809 // FIXME: right now we emulate params with loads; that should be fixed.
810 til::SExpr *Lp = new (Arena) til::LiteralPtr(Pm);
811 til::SExpr *Ld = new (Arena) til::Load(Lp);
812 til::SExpr *V = addStatement(Ld, nullptr, Pm);
817 void SExprBuilder::enterCFGBlock(const CFGBlock *B) {
818 // Intialize TIL basic block and add it to the CFG.
819 CurrentBB = lookupBlock(B);
820 CurrentBB->reservePredecessors(B->pred_size());
821 Scfg->add(CurrentBB);
823 CurrentBlockInfo = &BBInfo[B->getBlockID()];
825 // CurrentLVarMap is moved to ExitMap on block exit.
826 // FIXME: the entry block will hold function parameters.
827 // assert(!CurrentLVarMap.valid() && "CurrentLVarMap already initialized.");
830 void SExprBuilder::handlePredecessor(const CFGBlock *Pred) {
831 // Compute CurrentLVarMap on entry from ExitMaps of predecessors
833 CurrentBB->addPredecessor(BlockMap[Pred->getBlockID()]);
834 BlockInfo *PredInfo = &BBInfo[Pred->getBlockID()];
835 assert(PredInfo->UnprocessedSuccessors > 0);
837 if (--PredInfo->UnprocessedSuccessors == 0)
838 mergeEntryMap(std::move(PredInfo->ExitMap));
840 mergeEntryMap(PredInfo->ExitMap.clone());
842 ++CurrentBlockInfo->ProcessedPredecessors;
845 void SExprBuilder::handlePredecessorBackEdge(const CFGBlock *Pred) {
846 mergeEntryMapBackEdge();
849 void SExprBuilder::enterCFGBlockBody(const CFGBlock *B) {
850 // The merge*() methods have created arguments.
851 // Push those arguments onto the basic block.
852 CurrentBB->arguments().reserve(
853 static_cast<unsigned>(CurrentArguments.size()), Arena);
854 for (auto *A : CurrentArguments)
855 CurrentBB->addArgument(A);
858 void SExprBuilder::handleStatement(const Stmt *S) {
859 til::SExpr *E = translate(S, nullptr);
863 void SExprBuilder::handleDestructorCall(const VarDecl *VD,
864 const CXXDestructorDecl *DD) {
865 til::SExpr *Sf = new (Arena) til::LiteralPtr(VD);
866 til::SExpr *Dr = new (Arena) til::LiteralPtr(DD);
867 til::SExpr *Ap = new (Arena) til::Apply(Dr, Sf);
868 til::SExpr *E = new (Arena) til::Call(Ap);
869 addStatement(E, nullptr);
872 void SExprBuilder::exitCFGBlockBody(const CFGBlock *B) {
873 CurrentBB->instructions().reserve(
874 static_cast<unsigned>(CurrentInstructions.size()), Arena);
875 for (auto *V : CurrentInstructions)
876 CurrentBB->addInstruction(V);
878 // Create an appropriate terminator
879 unsigned N = B->succ_size();
880 auto It = B->succ_begin();
882 til::BasicBlock *BB = *It ? lookupBlock(*It) : nullptr;
884 unsigned Idx = BB ? BB->findPredecessorIndex(CurrentBB) : 0;
885 auto *Tm = new (Arena) til::Goto(BB, Idx);
886 CurrentBB->setTerminator(Tm);
889 til::SExpr *C = translate(B->getTerminatorCondition(true), nullptr);
890 til::BasicBlock *BB1 = *It ? lookupBlock(*It) : nullptr;
892 til::BasicBlock *BB2 = *It ? lookupBlock(*It) : nullptr;
893 // FIXME: make sure these arent' critical edges.
894 auto *Tm = new (Arena) til::Branch(C, BB1, BB2);
895 CurrentBB->setTerminator(Tm);
899 void SExprBuilder::handleSuccessor(const CFGBlock *Succ) {
900 ++CurrentBlockInfo->UnprocessedSuccessors;
903 void SExprBuilder::handleSuccessorBackEdge(const CFGBlock *Succ) {
904 mergePhiNodesBackEdge(Succ);
905 ++BBInfo[Succ->getBlockID()].ProcessedPredecessors;
908 void SExprBuilder::exitCFGBlock(const CFGBlock *B) {
909 CurrentArguments.clear();
910 CurrentInstructions.clear();
911 CurrentBlockInfo->ExitMap = std::move(CurrentLVarMap);
913 CurrentBlockInfo = nullptr;
916 void SExprBuilder::exitCFG(const CFGBlock *Last) {
917 for (auto *Ph : IncompleteArgs) {
918 if (Ph->status() == til::Phi::PH_Incomplete)
919 simplifyIncompleteArg(Ph);
922 CurrentArguments.clear();
923 CurrentInstructions.clear();
924 IncompleteArgs.clear();
928 void printSCFG(CFGWalker &Walker) {
929 llvm::BumpPtrAllocator Bpa;
930 til::MemRegionRef Arena(&Bpa);
931 SExprBuilder SxBuilder(Arena);
932 til::SCFG *Scfg = SxBuilder.buildCFG(Walker);
933 TILPrinter::print(Scfg, llvm::errs());