clang/lib/Analysis/ThreadSafetyCommon.cpp

   1 //===- ThreadSafetyCommon.cpp ---------------------------------------------===//
   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 // Implementation of the interfaces declared in ThreadSafetyCommon.h
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "clang/Analysis/Analyses/ThreadSafetyCommon.h"
  14 #include "clang/AST/Attr.h"
  15 #include "clang/AST/Decl.h"
  16 #include "clang/AST/DeclCXX.h"
  17 #include "clang/AST/DeclGroup.h"
  18 #include "clang/AST/DeclObjC.h"
  19 #include "clang/AST/Expr.h"
  20 #include "clang/AST/ExprCXX.h"
  21 #include "clang/AST/OperationKinds.h"
  22 #include "clang/AST/Stmt.h"
  23 #include "clang/AST/Type.h"
  24 #include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
  25 #include "clang/Analysis/CFG.h"
  26 #include "clang/Basic/LLVM.h"
  27 #include "clang/Basic/OperatorKinds.h"
  28 #include "clang/Basic/Specifiers.h"
  29 #include "llvm/ADT/StringExtras.h"
  30 #include "llvm/ADT/StringRef.h"
  31 #include "llvm/Support/Casting.h"
  32 #include <algorithm>
  33 #include <cassert>
  34 #include <string>
  35 #include <utility>
  36
  37 using namespace clang;
  38 using namespace threadSafety;
  39
  40 // From ThreadSafetyUtil.h
  41 std::string threadSafety::getSourceLiteralString(const Expr *CE) {
  42   switch (CE->getStmtClass()) {
  43     case Stmt::IntegerLiteralClass:
  44       return toString(cast<IntegerLiteral>(CE)->getValue(), 10, true);
  45     case Stmt::StringLiteralClass: {
  46       std::string ret("\"");
  47       ret += cast<StringLiteral>(CE)->getString();
  48       ret += "\"";
  49       return ret;
  50     }
  51     case Stmt::CharacterLiteralClass:
  52     case Stmt::CXXNullPtrLiteralExprClass:
  53     case Stmt::GNUNullExprClass:
  54     case Stmt::CXXBoolLiteralExprClass:
  55     case Stmt::FloatingLiteralClass:
  56     case Stmt::ImaginaryLiteralClass:
  57     case Stmt::ObjCStringLiteralClass:
  58     default:
  59       return "#lit";
  60   }
  61 }
  62
  63 // Return true if E is a variable that points to an incomplete Phi node.
  64 static bool isIncompletePhi(const til::SExpr *E) {
  65   if (const auto *Ph = dyn_cast<til::Phi>(E))
  66     return Ph->status() == til::Phi::PH_Incomplete;
  67   return false;
  68 }
  69
  70 using CallingContext = SExprBuilder::CallingContext;
  71
  72 til::SExpr *SExprBuilder::lookupStmt(const Stmt *S) { return SMap.lookup(S); }
  73
  74 til::SCFG *SExprBuilder::buildCFG(CFGWalker &Walker) {
  75   Walker.walk(*this);
  76   return Scfg;
  77 }
  78
  79 static bool isCalleeArrow(const Expr *E) {
  80   const auto *ME = dyn_cast<MemberExpr>(E->IgnoreParenCasts());
  81   return ME ? ME->isArrow() : false;
  82 }
  83
  84 static StringRef ClassifyDiagnostic(const CapabilityAttr *A) {
  85   return A->getName();
  86 }
  87
  88 static StringRef ClassifyDiagnostic(QualType VDT) {
  89   // We need to look at the declaration of the type of the value to determine
  90   // which it is. The type should either be a record or a typedef, or a pointer
  91   // or reference thereof.
  92   if (const auto *RT = VDT->getAs<RecordType>()) {
  93     if (const auto *RD = RT->getDecl())
  94       if (const auto *CA = RD->getAttr<CapabilityAttr>())
  95         return ClassifyDiagnostic(CA);
  96   } else if (const auto *TT = VDT->getAs<TypedefType>()) {
  97     if (const auto *TD = TT->getDecl())
  98       if (const auto *CA = TD->getAttr<CapabilityAttr>())
  99         return ClassifyDiagnostic(CA);
 100   } else if (VDT->isPointerOrReferenceType())
 101     return ClassifyDiagnostic(VDT->getPointeeType());
 102
 103   return "mutex";
 104 }
 105
 106 /// Translate a clang expression in an attribute to a til::SExpr.
 107 /// Constructs the context from D, DeclExp, and SelfDecl.
 108 ///
 109 /// \param AttrExp The expression to translate.
 110 /// \param D       The declaration to which the attribute is attached.
 111 /// \param DeclExp An expression involving the Decl to which the attribute
 112 ///                is attached.  E.g. the call to a function.
 113 /// \param Self    S-expression to substitute for a \ref CXXThisExpr in a call,
 114 ///                or argument to a cleanup function.
 115 CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
 116                                                const NamedDecl *D,
 117                                                const Expr *DeclExp,
 118                                                til::SExpr *Self) {
 119   // If we are processing a raw attribute expression, with no substitutions.
 120   if (!DeclExp && !Self)
 121     return translateAttrExpr(AttrExp, nullptr);
 122
 123   CallingContext Ctx(nullptr, D);
 124
 125   // Examine DeclExp to find SelfArg and FunArgs, which are used to substitute
 126   // for formal parameters when we call buildMutexID later.
 127   if (!DeclExp)
 128     /* We'll use Self. */;
 129   else if (const auto *ME = dyn_cast<MemberExpr>(DeclExp)) {
 130     Ctx.SelfArg   = ME->getBase();
 131     Ctx.SelfArrow = ME->isArrow();
 132   } else if (const auto *CE = dyn_cast<CXXMemberCallExpr>(DeclExp)) {
 133     Ctx.SelfArg   = CE->getImplicitObjectArgument();
 134     Ctx.SelfArrow = isCalleeArrow(CE->getCallee());
 135     Ctx.NumArgs   = CE->getNumArgs();
 136     Ctx.FunArgs   = CE->getArgs();
 137   } else if (const auto *CE = dyn_cast<CallExpr>(DeclExp)) {
 138     Ctx.NumArgs = CE->getNumArgs();
 139     Ctx.FunArgs = CE->getArgs();
 140   } else if (const auto *CE = dyn_cast<CXXConstructExpr>(DeclExp)) {
 141     Ctx.SelfArg = nullptr;  // Will be set below
 142     Ctx.NumArgs = CE->getNumArgs();
 143     Ctx.FunArgs = CE->getArgs();
 144   }
 145
 146   if (Self) {
 147     assert(!Ctx.SelfArg && "Ambiguous self argument");
 148     assert(isa<FunctionDecl>(D) && "Self argument requires function");
 149     if (isa<CXXMethodDecl>(D))
 150       Ctx.SelfArg = Self;
 151     else
 152       Ctx.FunArgs = Self;
 153
 154     // If the attribute has no arguments, then assume the argument is "this".
 155     if (!AttrExp)
 156       return CapabilityExpr(
 157           Self,
 158           ClassifyDiagnostic(
 159               cast<CXXMethodDecl>(D)->getFunctionObjectParameterType()),
 160           false);
 161     else  // For most attributes.
 162       return translateAttrExpr(AttrExp, &Ctx);
 163   }
 164
 165   // If the attribute has no arguments, then assume the argument is "this".
 166   if (!AttrExp)
 167     return translateAttrExpr(cast<const Expr *>(Ctx.SelfArg), nullptr);
 168   else  // For most attributes.
 169     return translateAttrExpr(AttrExp, &Ctx);
 170 }
 171
 172 /// Translate a clang expression in an attribute to a til::SExpr.
 173 // This assumes a CallingContext has already been created.
 174 CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
 175                                                CallingContext *Ctx) {
 176   if (!AttrExp)
 177     return CapabilityExpr();
 178
 179   if (const auto* SLit = dyn_cast<StringLiteral>(AttrExp)) {
 180     if (SLit->getString() == "*")
 181       // The "*" expr is a universal lock, which essentially turns off
 182       // checks until it is removed from the lockset.
 183       return CapabilityExpr(new (Arena) til::Wildcard(), StringRef("wildcard"),
 184                             false);
 185     else
 186       // Ignore other string literals for now.
 187       return CapabilityExpr();
 188   }
 189
 190   bool Neg = false;
 191   if (const auto *OE = dyn_cast<CXXOperatorCallExpr>(AttrExp)) {
 192     if (OE->getOperator() == OO_Exclaim) {
 193       Neg = true;
 194       AttrExp = OE->getArg(0);
 195     }
 196   }
 197   else if (const auto *UO = dyn_cast<UnaryOperator>(AttrExp)) {
 198     if (UO->getOpcode() == UO_LNot) {
 199       Neg = true;
 200       AttrExp = UO->getSubExpr()->IgnoreImplicit();
 201     }
 202   }
 203
 204   til::SExpr *E = translate(AttrExp, Ctx);
 205
 206   // Trap mutex expressions like nullptr, or 0.
 207   // Any literal value is nonsense.
 208   if (!E || isa<til::Literal>(E))
 209     return CapabilityExpr();
 210
 211   StringRef Kind = ClassifyDiagnostic(AttrExp->getType());
 212
 213   // Hack to deal with smart pointers -- strip off top-level pointer casts.
 214   if (const auto *CE = dyn_cast<til::Cast>(E)) {
 215     if (CE->castOpcode() == til::CAST_objToPtr)
 216       return CapabilityExpr(CE->expr(), Kind, Neg);
 217   }
 218   return CapabilityExpr(E, Kind, Neg);
 219 }
 220
 221 til::LiteralPtr *SExprBuilder::createVariable(const VarDecl *VD) {
 222   return new (Arena) til::LiteralPtr(VD);
 223 }
 224
 225 std::pair<til::LiteralPtr *, StringRef>
 226 SExprBuilder::createThisPlaceholder(const Expr *Exp) {
 227   return {new (Arena) til::LiteralPtr(nullptr),
 228           ClassifyDiagnostic(Exp->getType())};
 229 }
 230
 231 // Translate a clang statement or expression to a TIL expression.
 232 // Also performs substitution of variables; Ctx provides the context.
 233 // Dispatches on the type of S.
 234 til::SExpr *SExprBuilder::translate(const Stmt *S, CallingContext *Ctx) {
 235   if (!S)
 236     return nullptr;
 237
 238   // Check if S has already been translated and cached.
 239   // This handles the lookup of SSA names for DeclRefExprs here.
 240   if (til::SExpr *E = lookupStmt(S))
 241     return E;
 242
 243   switch (S->getStmtClass()) {
 244   case Stmt::DeclRefExprClass:
 245     return translateDeclRefExpr(cast<DeclRefExpr>(S), Ctx);
 246   case Stmt::CXXThisExprClass:
 247     return translateCXXThisExpr(cast<CXXThisExpr>(S), Ctx);
 248   case Stmt::MemberExprClass:
 249     return translateMemberExpr(cast<MemberExpr>(S), Ctx);
 250   case Stmt::ObjCIvarRefExprClass:
 251     return translateObjCIVarRefExpr(cast<ObjCIvarRefExpr>(S), Ctx);
 252   case Stmt::CallExprClass:
 253     return translateCallExpr(cast<CallExpr>(S), Ctx);
 254   case Stmt::CXXMemberCallExprClass:
 255     return translateCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), Ctx);
 256   case Stmt::CXXOperatorCallExprClass:
 257     return translateCXXOperatorCallExpr(cast<CXXOperatorCallExpr>(S), Ctx);
 258   case Stmt::UnaryOperatorClass:
 259     return translateUnaryOperator(cast<UnaryOperator>(S), Ctx);
 260   case Stmt::BinaryOperatorClass:
 261   case Stmt::CompoundAssignOperatorClass:
 262     return translateBinaryOperator(cast<BinaryOperator>(S), Ctx);
 263
 264   case Stmt::ArraySubscriptExprClass:
 265     return translateArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Ctx);
 266   case Stmt::ConditionalOperatorClass:
 267     return translateAbstractConditionalOperator(
 268              cast<ConditionalOperator>(S), Ctx);
 269   case Stmt::BinaryConditionalOperatorClass:
 270     return translateAbstractConditionalOperator(
 271              cast<BinaryConditionalOperator>(S), Ctx);
 272
 273   // We treat these as no-ops
 274   case Stmt::ConstantExprClass:
 275     return translate(cast<ConstantExpr>(S)->getSubExpr(), Ctx);
 276   case Stmt::ParenExprClass:
 277     return translate(cast<ParenExpr>(S)->getSubExpr(), Ctx);
 278   case Stmt::ExprWithCleanupsClass:
 279     return translate(cast<ExprWithCleanups>(S)->getSubExpr(), Ctx);
 280   case Stmt::CXXBindTemporaryExprClass:
 281     return translate(cast<CXXBindTemporaryExpr>(S)->getSubExpr(), Ctx);
 282   case Stmt::MaterializeTemporaryExprClass:
 283     return translate(cast<MaterializeTemporaryExpr>(S)->getSubExpr(), Ctx);
 284
 285   // Collect all literals
 286   case Stmt::CharacterLiteralClass:
 287   case Stmt::CXXNullPtrLiteralExprClass:
 288   case Stmt::GNUNullExprClass:
 289   case Stmt::CXXBoolLiteralExprClass:
 290   case Stmt::FloatingLiteralClass:
 291   case Stmt::ImaginaryLiteralClass:
 292   case Stmt::IntegerLiteralClass:
 293   case Stmt::StringLiteralClass:
 294   case Stmt::ObjCStringLiteralClass:
 295     return new (Arena) til::Literal(cast<Expr>(S));
 296
 297   case Stmt::DeclStmtClass:
 298     return translateDeclStmt(cast<DeclStmt>(S), Ctx);
 299   default:
 300     break;
 301   }
 302   if (const auto *CE = dyn_cast<CastExpr>(S))
 303     return translateCastExpr(CE, Ctx);
 304
 305   return new (Arena) til::Undefined(S);
 306 }
 307
 308 til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
 309                                                CallingContext *Ctx) {
 310   const auto *VD = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
 311
 312   // Function parameters require substitution and/or renaming.
 313   if (const auto *PV = dyn_cast<ParmVarDecl>(VD)) {
 314     unsigned I = PV->getFunctionScopeIndex();
 315     const DeclContext *D = PV->getDeclContext();
 316     if (Ctx && Ctx->FunArgs) {
 317       const Decl *Canonical = Ctx->AttrDecl->getCanonicalDecl();
 318       if (isa<FunctionDecl>(D)
 319               ? (cast<FunctionDecl>(D)->getCanonicalDecl() == Canonical)
 320               : (cast<ObjCMethodDecl>(D)->getCanonicalDecl() == Canonical)) {
 321         // Substitute call arguments for references to function parameters
 322         if (const Expr *const *FunArgs =
 323                 Ctx->FunArgs.dyn_cast<const Expr *const *>()) {
 324           assert(I < Ctx->NumArgs);
 325           return translate(FunArgs[I], Ctx->Prev);
 326         }
 327
 328         assert(I == 0);
 329         return Ctx->FunArgs.get<til::SExpr *>();
 330       }
 331     }
 332     // Map the param back to the param of the original function declaration
 333     // for consistent comparisons.
 334     VD = isa<FunctionDecl>(D)
 335              ? cast<FunctionDecl>(D)->getCanonicalDecl()->getParamDecl(I)
 336              : cast<ObjCMethodDecl>(D)->getCanonicalDecl()->getParamDecl(I);
 337   }
 338
 339   // For non-local variables, treat it as a reference to a named object.
 340   return new (Arena) til::LiteralPtr(VD);
 341 }
 342
 343 til::SExpr *SExprBuilder::translateCXXThisExpr(const CXXThisExpr *TE,
 344                                                CallingContext *Ctx) {
 345   // Substitute for 'this'
 346   if (Ctx && Ctx->SelfArg) {
 347     if (const auto *SelfArg = dyn_cast<const Expr *>(Ctx->SelfArg))
 348       return translate(SelfArg, Ctx->Prev);
 349     else
 350       return cast<til::SExpr *>(Ctx->SelfArg);
 351   }
 352   assert(SelfVar && "We have no variable for 'this'!");
 353   return SelfVar;
 354 }
 355
 356 static const ValueDecl *getValueDeclFromSExpr(const til::SExpr *E) {
 357   if (const auto *V = dyn_cast<til::Variable>(E))
 358     return V->clangDecl();
 359   if (const auto *Ph = dyn_cast<til::Phi>(E))
 360     return Ph->clangDecl();
 361   if (const auto *P = dyn_cast<til::Project>(E))
 362     return P->clangDecl();
 363   if (const auto *L = dyn_cast<til::LiteralPtr>(E))
 364     return L->clangDecl();
 365   return nullptr;
 366 }
 367
 368 static bool hasAnyPointerType(const til::SExpr *E) {
 369   auto *VD = getValueDeclFromSExpr(E);
 370   if (VD && VD->getType()->isAnyPointerType())
 371     return true;
 372   if (const auto *C = dyn_cast<til::Cast>(E))
 373     return C->castOpcode() == til::CAST_objToPtr;
 374
 375   return false;
 376 }
 377
 378 // Grab the very first declaration of virtual method D
 379 static const CXXMethodDecl *getFirstVirtualDecl(const CXXMethodDecl *D) {
 380   while (true) {
 381     D = D->getCanonicalDecl();
 382     auto OverriddenMethods = D->overridden_methods();
 383     if (OverriddenMethods.begin() == OverriddenMethods.end())
 384       return D;  // Method does not override anything
 385     // FIXME: this does not work with multiple inheritance.
 386     D = *OverriddenMethods.begin();
 387   }
 388   return nullptr;
 389 }
 390
 391 til::SExpr *SExprBuilder::translateMemberExpr(const MemberExpr *ME,
 392                                               CallingContext *Ctx) {
 393   til::SExpr *BE = translate(ME->getBase(), Ctx);
 394   til::SExpr *E  = new (Arena) til::SApply(BE);
 395
 396   const auto *D = cast<ValueDecl>(ME->getMemberDecl()->getCanonicalDecl());
 397   if (const auto *VD = dyn_cast<CXXMethodDecl>(D))
 398     D = getFirstVirtualDecl(VD);
 399
 400   til::Project *P = new (Arena) til::Project(E, D);
 401   if (hasAnyPointerType(BE))
 402     P->setArrow(true);
 403   return P;
 404 }
 405
 406 til::SExpr *SExprBuilder::translateObjCIVarRefExpr(const ObjCIvarRefExpr *IVRE,
 407                                                    CallingContext *Ctx) {
 408   til::SExpr *BE = translate(IVRE->getBase(), Ctx);
 409   til::SExpr *E = new (Arena) til::SApply(BE);
 410
 411   const auto *D = cast<ObjCIvarDecl>(IVRE->getDecl()->getCanonicalDecl());
 412
 413   til::Project *P = new (Arena) til::Project(E, D);
 414   if (hasAnyPointerType(BE))
 415     P->setArrow(true);
 416   return P;
 417 }
 418
 419 til::SExpr *SExprBuilder::translateCallExpr(const CallExpr *CE,
 420                                             CallingContext *Ctx,
 421                                             const Expr *SelfE) {
 422   if (CapabilityExprMode) {
 423     // Handle LOCK_RETURNED
 424     if (const FunctionDecl *FD = CE->getDirectCallee()) {
 425       FD = FD->getMostRecentDecl();
 426       if (LockReturnedAttr *At = FD->getAttr<LockReturnedAttr>()) {
 427         CallingContext LRCallCtx(Ctx);
 428         LRCallCtx.AttrDecl = CE->getDirectCallee();
 429         LRCallCtx.SelfArg = SelfE;
 430         LRCallCtx.NumArgs = CE->getNumArgs();
 431         LRCallCtx.FunArgs = CE->getArgs();
 432         return const_cast<til::SExpr *>(
 433             translateAttrExpr(At->getArg(), &LRCallCtx).sexpr());
 434       }
 435     }
 436   }
 437
 438   til::SExpr *E = translate(CE->getCallee(), Ctx);
 439   for (const auto *Arg : CE->arguments()) {
 440     til::SExpr *A = translate(Arg, Ctx);
 441     E = new (Arena) til::Apply(E, A);
 442   }
 443   return new (Arena) til::Call(E, CE);
 444 }
 445
 446 til::SExpr *SExprBuilder::translateCXXMemberCallExpr(
 447     const CXXMemberCallExpr *ME, CallingContext *Ctx) {
 448   if (CapabilityExprMode) {
 449     // Ignore calls to get() on smart pointers.
 450     if (ME->getMethodDecl()->getNameAsString() == "get" &&
 451         ME->getNumArgs() == 0) {
 452       auto *E = translate(ME->getImplicitObjectArgument(), Ctx);
 453       return new (Arena) til::Cast(til::CAST_objToPtr, E);
 454       // return E;
 455     }
 456   }
 457   return translateCallExpr(cast<CallExpr>(ME), Ctx,
 458                            ME->getImplicitObjectArgument());
 459 }
 460
 461 til::SExpr *SExprBuilder::translateCXXOperatorCallExpr(
 462     const CXXOperatorCallExpr *OCE, CallingContext *Ctx) {
 463   if (CapabilityExprMode) {
 464     // Ignore operator * and operator -> on smart pointers.
 465     OverloadedOperatorKind k = OCE->getOperator();
 466     if (k == OO_Star || k == OO_Arrow) {
 467       auto *E = translate(OCE->getArg(0), Ctx);
 468       return new (Arena) til::Cast(til::CAST_objToPtr, E);
 469       // return E;
 470     }
 471   }
 472   return translateCallExpr(cast<CallExpr>(OCE), Ctx);
 473 }
 474
 475 til::SExpr *SExprBuilder::translateUnaryOperator(const UnaryOperator *UO,
 476                                                  CallingContext *Ctx) {
 477   switch (UO->getOpcode()) {
 478   case UO_PostInc:
 479   case UO_PostDec:
 480   case UO_PreInc:
 481   case UO_PreDec:
 482     return new (Arena) til::Undefined(UO);
 483
 484   case UO_AddrOf:
 485     if (CapabilityExprMode) {
 486       // interpret &Graph::mu_ as an existential.
 487       if (const auto *DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr())) {
 488         if (DRE->getDecl()->isCXXInstanceMember()) {
 489           // This is a pointer-to-member expression, e.g. &MyClass::mu_.
 490           // We interpret this syntax specially, as a wildcard.
 491           auto *W = new (Arena) til::Wildcard();
 492           return new (Arena) til::Project(W, DRE->getDecl());
 493         }
 494       }
 495     }
 496     // otherwise, & is a no-op
 497     return translate(UO->getSubExpr(), Ctx);
 498
 499   // We treat these as no-ops
 500   case UO_Deref:
 501   case UO_Plus:
 502     return translate(UO->getSubExpr(), Ctx);
 503
 504   case UO_Minus:
 505     return new (Arena)
 506       til::UnaryOp(til::UOP_Minus, translate(UO->getSubExpr(), Ctx));
 507   case UO_Not:
 508     return new (Arena)
 509       til::UnaryOp(til::UOP_BitNot, translate(UO->getSubExpr(), Ctx));
 510   case UO_LNot:
 511     return new (Arena)
 512       til::UnaryOp(til::UOP_LogicNot, translate(UO->getSubExpr(), Ctx));
 513
 514   // Currently unsupported
 515   case UO_Real:
 516   case UO_Imag:
 517   case UO_Extension:
 518   case UO_Coawait:
 519     return new (Arena) til::Undefined(UO);
 520   }
 521   return new (Arena) til::Undefined(UO);
 522 }
 523
 524 til::SExpr *SExprBuilder::translateBinOp(til::TIL_BinaryOpcode Op,
 525                                          const BinaryOperator *BO,
 526                                          CallingContext *Ctx, bool Reverse) {
 527    til::SExpr *E0 = translate(BO->getLHS(), Ctx);
 528    til::SExpr *E1 = translate(BO->getRHS(), Ctx);
 529    if (Reverse)
 530      return new (Arena) til::BinaryOp(Op, E1, E0);
 531    else
 532      return new (Arena) til::BinaryOp(Op, E0, E1);
 533 }
 534
 535 til::SExpr *SExprBuilder::translateBinAssign(til::TIL_BinaryOpcode Op,
 536                                              const BinaryOperator *BO,
 537                                              CallingContext *Ctx,
 538                                              bool Assign) {
 539   const Expr *LHS = BO->getLHS();
 540   const Expr *RHS = BO->getRHS();
 541   til::SExpr *E0 = translate(LHS, Ctx);
 542   til::SExpr *E1 = translate(RHS, Ctx);
 543
 544   const ValueDecl *VD = nullptr;
 545   til::SExpr *CV = nullptr;
 546   if (const auto *DRE = dyn_cast<DeclRefExpr>(LHS)) {
 547     VD = DRE->getDecl();
 548     CV = lookupVarDecl(VD);
 549   }
 550
 551   if (!Assign) {
 552     til::SExpr *Arg = CV ? CV : new (Arena) til::Load(E0);
 553     E1 = new (Arena) til::BinaryOp(Op, Arg, E1);
 554     E1 = addStatement(E1, nullptr, VD);
 555   }
 556   if (VD && CV)
 557     return updateVarDecl(VD, E1);
 558   return new (Arena) til::Store(E0, E1);
 559 }
 560
 561 til::SExpr *SExprBuilder::translateBinaryOperator(const BinaryOperator *BO,
 562                                                   CallingContext *Ctx) {
 563   switch (BO->getOpcode()) {
 564   case BO_PtrMemD:
 565   case BO_PtrMemI:
 566     return new (Arena) til::Undefined(BO);
 567
 568   case BO_Mul:  return translateBinOp(til::BOP_Mul, BO, Ctx);
 569   case BO_Div:  return translateBinOp(til::BOP_Div, BO, Ctx);
 570   case BO_Rem:  return translateBinOp(til::BOP_Rem, BO, Ctx);
 571   case BO_Add:  return translateBinOp(til::BOP_Add, BO, Ctx);
 572   case BO_Sub:  return translateBinOp(til::BOP_Sub, BO, Ctx);
 573   case BO_Shl:  return translateBinOp(til::BOP_Shl, BO, Ctx);
 574   case BO_Shr:  return translateBinOp(til::BOP_Shr, BO, Ctx);
 575   case BO_LT:   return translateBinOp(til::BOP_Lt,  BO, Ctx);
 576   case BO_GT:   return translateBinOp(til::BOP_Lt,  BO, Ctx, true);
 577   case BO_LE:   return translateBinOp(til::BOP_Leq, BO, Ctx);
 578   case BO_GE:   return translateBinOp(til::BOP_Leq, BO, Ctx, true);
 579   case BO_EQ:   return translateBinOp(til::BOP_Eq,  BO, Ctx);
 580   case BO_NE:   return translateBinOp(til::BOP_Neq, BO, Ctx);
 581   case BO_Cmp:  return translateBinOp(til::BOP_Cmp, BO, Ctx);
 582   case BO_And:  return translateBinOp(til::BOP_BitAnd,   BO, Ctx);
 583   case BO_Xor:  return translateBinOp(til::BOP_BitXor,   BO, Ctx);
 584   case BO_Or:   return translateBinOp(til::BOP_BitOr,    BO, Ctx);
 585   case BO_LAnd: return translateBinOp(til::BOP_LogicAnd, BO, Ctx);
 586   case BO_LOr:  return translateBinOp(til::BOP_LogicOr,  BO, Ctx);
 587
 588   case BO_Assign:    return translateBinAssign(til::BOP_Eq,  BO, Ctx, true);
 589   case BO_MulAssign: return translateBinAssign(til::BOP_Mul, BO, Ctx);
 590   case BO_DivAssign: return translateBinAssign(til::BOP_Div, BO, Ctx);
 591   case BO_RemAssign: return translateBinAssign(til::BOP_Rem, BO, Ctx);
 592   case BO_AddAssign: return translateBinAssign(til::BOP_Add, BO, Ctx);
 593   case BO_SubAssign: return translateBinAssign(til::BOP_Sub, BO, Ctx);
 594   case BO_ShlAssign: return translateBinAssign(til::BOP_Shl, BO, Ctx);
 595   case BO_ShrAssign: return translateBinAssign(til::BOP_Shr, BO, Ctx);
 596   case BO_AndAssign: return translateBinAssign(til::BOP_BitAnd, BO, Ctx);
 597   case BO_XorAssign: return translateBinAssign(til::BOP_BitXor, BO, Ctx);
 598   case BO_OrAssign:  return translateBinAssign(til::BOP_BitOr,  BO, Ctx);
 599
 600   case BO_Comma:
 601     // The clang CFG should have already processed both sides.
 602     return translate(BO->getRHS(), Ctx);
 603   }
 604   return new (Arena) til::Undefined(BO);
 605 }
 606
 607 til::SExpr *SExprBuilder::translateCastExpr(const CastExpr *CE,
 608                                             CallingContext *Ctx) {
 609   CastKind K = CE->getCastKind();
 610   switch (K) {
 611   case CK_LValueToRValue: {
 612     if (const auto *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
 613       til::SExpr *E0 = lookupVarDecl(DRE->getDecl());
 614       if (E0)
 615         return E0;
 616     }
 617     til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
 618     return E0;
 619     // FIXME!! -- get Load working properly
 620     // return new (Arena) til::Load(E0);
 621   }
 622   case CK_NoOp:
 623   case CK_DerivedToBase:
 624   case CK_UncheckedDerivedToBase:
 625   case CK_ArrayToPointerDecay:
 626   case CK_FunctionToPointerDecay: {
 627     til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
 628     return E0;
 629   }
 630   default: {
 631     // FIXME: handle different kinds of casts.
 632     til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
 633     if (CapabilityExprMode)
 634       return E0;
 635     return new (Arena) til::Cast(til::CAST_none, E0);
 636   }
 637   }
 638 }
 639
 640 til::SExpr *
 641 SExprBuilder::translateArraySubscriptExpr(const ArraySubscriptExpr *E,
 642                                           CallingContext *Ctx) {
 643   til::SExpr *E0 = translate(E->getBase(), Ctx);
 644   til::SExpr *E1 = translate(E->getIdx(), Ctx);
 645   return new (Arena) til::ArrayIndex(E0, E1);
 646 }
 647
 648 til::SExpr *
 649 SExprBuilder::translateAbstractConditionalOperator(
 650     const AbstractConditionalOperator *CO, CallingContext *Ctx) {
 651   auto *C = translate(CO->getCond(), Ctx);
 652   auto *T = translate(CO->getTrueExpr(), Ctx);
 653   auto *E = translate(CO->getFalseExpr(), Ctx);
 654   return new (Arena) til::IfThenElse(C, T, E);
 655 }
 656
 657 til::SExpr *
 658 SExprBuilder::translateDeclStmt(const DeclStmt *S, CallingContext *Ctx) {
 659   DeclGroupRef DGrp = S->getDeclGroup();
 660   for (auto *I : DGrp) {
 661     if (auto *VD = dyn_cast_or_null<VarDecl>(I)) {
 662       Expr *E = VD->getInit();
 663       til::SExpr* SE = translate(E, Ctx);
 664
 665       // Add local variables with trivial type to the variable map
 666       QualType T = VD->getType();
 667       if (T.isTrivialType(VD->getASTContext()))
 668         return addVarDecl(VD, SE);
 669       else {
 670         // TODO: add alloca
 671       }
 672     }
 673   }
 674   return nullptr;
 675 }
 676
 677 // If (E) is non-trivial, then add it to the current basic block, and
 678 // update the statement map so that S refers to E.  Returns a new variable
 679 // that refers to E.
 680 // If E is trivial returns E.
 681 til::SExpr *SExprBuilder::addStatement(til::SExpr* E, const Stmt *S,
 682                                        const ValueDecl *VD) {
 683   if (!E || !CurrentBB || E->block() || til::ThreadSafetyTIL::isTrivial(E))
 684     return E;
 685   if (VD)
 686     E = new (Arena) til::Variable(E, VD);
 687   CurrentInstructions.push_back(E);
 688   if (S)
 689     insertStmt(S, E);
 690   return E;
 691 }
 692
 693 // Returns the current value of VD, if known, and nullptr otherwise.
 694 til::SExpr *SExprBuilder::lookupVarDecl(const ValueDecl *VD) {
 695   auto It = LVarIdxMap.find(VD);
 696   if (It != LVarIdxMap.end()) {
 697     assert(CurrentLVarMap[It->second].first == VD);
 698     return CurrentLVarMap[It->second].second;
 699   }
 700   return nullptr;
 701 }
 702
 703 // if E is a til::Variable, update its clangDecl.
 704 static void maybeUpdateVD(til::SExpr *E, const ValueDecl *VD) {
 705   if (!E)
 706     return;
 707   if (auto *V = dyn_cast<til::Variable>(E)) {
 708     if (!V->clangDecl())
 709       V->setClangDecl(VD);
 710   }
 711 }
 712
 713 // Adds a new variable declaration.
 714 til::SExpr *SExprBuilder::addVarDecl(const ValueDecl *VD, til::SExpr *E) {
 715   maybeUpdateVD(E, VD);
 716   LVarIdxMap.insert(std::make_pair(VD, CurrentLVarMap.size()));
 717   CurrentLVarMap.makeWritable();
 718   CurrentLVarMap.push_back(std::make_pair(VD, E));
 719   return E;
 720 }
 721
 722 // Updates a current variable declaration.  (E.g. by assignment)
 723 til::SExpr *SExprBuilder::updateVarDecl(const ValueDecl *VD, til::SExpr *E) {
 724   maybeUpdateVD(E, VD);
 725   auto It = LVarIdxMap.find(VD);
 726   if (It == LVarIdxMap.end()) {
 727     til::SExpr *Ptr = new (Arena) til::LiteralPtr(VD);
 728     til::SExpr *St  = new (Arena) til::Store(Ptr, E);
 729     return St;
 730   }
 731   CurrentLVarMap.makeWritable();
 732   CurrentLVarMap.elem(It->second).second = E;
 733   return E;
 734 }
 735
 736 // Make a Phi node in the current block for the i^th variable in CurrentVarMap.
 737 // If E != null, sets Phi[CurrentBlockInfo->ArgIndex] = E.
 738 // If E == null, this is a backedge and will be set later.
 739 void SExprBuilder::makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E) {
 740   unsigned ArgIndex = CurrentBlockInfo->ProcessedPredecessors;
 741   assert(ArgIndex > 0 && ArgIndex < NPreds);
 742
 743   til::SExpr *CurrE = CurrentLVarMap[i].second;
 744   if (CurrE->block() == CurrentBB) {
 745     // We already have a Phi node in the current block,
 746     // so just add the new variable to the Phi node.
 747     auto *Ph = dyn_cast<til::Phi>(CurrE);
 748     assert(Ph && "Expecting Phi node.");
 749     if (E)
 750       Ph->values()[ArgIndex] = E;
 751     return;
 752   }
 753
 754   // Make a new phi node: phi(..., E)
 755   // All phi args up to the current index are set to the current value.
 756   til::Phi *Ph = new (Arena) til::Phi(Arena, NPreds);
 757   Ph->values().setValues(NPreds, nullptr);
 758   for (unsigned PIdx = 0; PIdx < ArgIndex; ++PIdx)
 759     Ph->values()[PIdx] = CurrE;
 760   if (E)
 761     Ph->values()[ArgIndex] = E;
 762   Ph->setClangDecl(CurrentLVarMap[i].first);
 763   // If E is from a back-edge, or either E or CurrE are incomplete, then
 764   // mark this node as incomplete; we may need to remove it later.
 765   if (!E || isIncompletePhi(E) || isIncompletePhi(CurrE))
 766     Ph->setStatus(til::Phi::PH_Incomplete);
 767
 768   // Add Phi node to current block, and update CurrentLVarMap[i]
 769   CurrentArguments.push_back(Ph);
 770   if (Ph->status() == til::Phi::PH_Incomplete)
 771     IncompleteArgs.push_back(Ph);
 772
 773   CurrentLVarMap.makeWritable();
 774   CurrentLVarMap.elem(i).second = Ph;
 775 }
 776
 777 // Merge values from Map into the current variable map.
 778 // This will construct Phi nodes in the current basic block as necessary.
 779 void SExprBuilder::mergeEntryMap(LVarDefinitionMap Map) {
 780   assert(CurrentBlockInfo && "Not processing a block!");
 781
 782   if (!CurrentLVarMap.valid()) {
 783     // Steal Map, using copy-on-write.
 784     CurrentLVarMap = std::move(Map);
 785     return;
 786   }
 787   if (CurrentLVarMap.sameAs(Map))
 788     return;  // Easy merge: maps from different predecessors are unchanged.
 789
 790   unsigned NPreds = CurrentBB->numPredecessors();
 791   unsigned ESz = CurrentLVarMap.size();
 792   unsigned MSz = Map.size();
 793   unsigned Sz  = std::min(ESz, MSz);
 794
 795   for (unsigned i = 0; i < Sz; ++i) {
 796     if (CurrentLVarMap[i].first != Map[i].first) {
 797       // We've reached the end of variables in common.
 798       CurrentLVarMap.makeWritable();
 799       CurrentLVarMap.downsize(i);
 800       break;
 801     }
 802     if (CurrentLVarMap[i].second != Map[i].second)
 803       makePhiNodeVar(i, NPreds, Map[i].second);
 804   }
 805   if (ESz > MSz) {
 806     CurrentLVarMap.makeWritable();
 807     CurrentLVarMap.downsize(Map.size());
 808   }
 809 }
 810
 811 // Merge a back edge into the current variable map.
 812 // This will create phi nodes for all variables in the variable map.
 813 void SExprBuilder::mergeEntryMapBackEdge() {
 814   // We don't have definitions for variables on the backedge, because we
 815   // haven't gotten that far in the CFG.  Thus, when encountering a back edge,
 816   // we conservatively create Phi nodes for all variables.  Unnecessary Phi
 817   // nodes will be marked as incomplete, and stripped out at the end.
 818   //
 819   // An Phi node is unnecessary if it only refers to itself and one other
 820   // variable, e.g. x = Phi(y, y, x)  can be reduced to x = y.
 821
 822   assert(CurrentBlockInfo && "Not processing a block!");
 823
 824   if (CurrentBlockInfo->HasBackEdges)
 825     return;
 826   CurrentBlockInfo->HasBackEdges = true;
 827
 828   CurrentLVarMap.makeWritable();
 829   unsigned Sz = CurrentLVarMap.size();
 830   unsigned NPreds = CurrentBB->numPredecessors();
 831
 832   for (unsigned i = 0; i < Sz; ++i)
 833     makePhiNodeVar(i, NPreds, nullptr);
 834 }
 835
 836 // Update the phi nodes that were initially created for a back edge
 837 // once the variable definitions have been computed.
 838 // I.e., merge the current variable map into the phi nodes for Blk.
 839 void SExprBuilder::mergePhiNodesBackEdge(const CFGBlock *Blk) {
 840   til::BasicBlock *BB = lookupBlock(Blk);
 841   unsigned ArgIndex = BBInfo[Blk->getBlockID()].ProcessedPredecessors;
 842   assert(ArgIndex > 0 && ArgIndex < BB->numPredecessors());
 843
 844   for (til::SExpr *PE : BB->arguments()) {
 845     auto *Ph = dyn_cast_or_null<til::Phi>(PE);
 846     assert(Ph && "Expecting Phi Node.");
 847     assert(Ph->values()[ArgIndex] == nullptr && "Wrong index for back edge.");
 848
 849     til::SExpr *E = lookupVarDecl(Ph->clangDecl());
 850     assert(E && "Couldn't find local variable for Phi node.");
 851     Ph->values()[ArgIndex] = E;
 852   }
 853 }
 854
 855 void SExprBuilder::enterCFG(CFG *Cfg, const NamedDecl *D,
 856                             const CFGBlock *First) {
 857   // Perform initial setup operations.
 858   unsigned NBlocks = Cfg->getNumBlockIDs();
 859   Scfg = new (Arena) til::SCFG(Arena, NBlocks);
 860
 861   // allocate all basic blocks immediately, to handle forward references.
 862   BBInfo.resize(NBlocks);
 863   BlockMap.resize(NBlocks, nullptr);
 864   // create map from clang blockID to til::BasicBlocks
 865   for (auto *B : *Cfg) {
 866     auto *BB = new (Arena) til::BasicBlock(Arena);
 867     BB->reserveInstructions(B->size());
 868     BlockMap[B->getBlockID()] = BB;
 869   }
 870
 871   CurrentBB = lookupBlock(&Cfg->getEntry());
 872   auto Parms = isa<ObjCMethodDecl>(D) ? cast<ObjCMethodDecl>(D)->parameters()
 873                                       : cast<FunctionDecl>(D)->parameters();
 874   for (auto *Pm : Parms) {
 875     QualType T = Pm->getType();
 876     if (!T.isTrivialType(Pm->getASTContext()))
 877       continue;
 878
 879     // Add parameters to local variable map.
 880     // FIXME: right now we emulate params with loads; that should be fixed.
 881     til::SExpr *Lp = new (Arena) til::LiteralPtr(Pm);
 882     til::SExpr *Ld = new (Arena) til::Load(Lp);
 883     til::SExpr *V  = addStatement(Ld, nullptr, Pm);
 884     addVarDecl(Pm, V);
 885   }
 886 }
 887
 888 void SExprBuilder::enterCFGBlock(const CFGBlock *B) {
 889   // Initialize TIL basic block and add it to the CFG.
 890   CurrentBB = lookupBlock(B);
 891   CurrentBB->reservePredecessors(B->pred_size());
 892   Scfg->add(CurrentBB);
 893
 894   CurrentBlockInfo = &BBInfo[B->getBlockID()];
 895
 896   // CurrentLVarMap is moved to ExitMap on block exit.
 897   // FIXME: the entry block will hold function parameters.
 898   // assert(!CurrentLVarMap.valid() && "CurrentLVarMap already initialized.");
 899 }
 900
 901 void SExprBuilder::handlePredecessor(const CFGBlock *Pred) {
 902   // Compute CurrentLVarMap on entry from ExitMaps of predecessors
 903
 904   CurrentBB->addPredecessor(BlockMap[Pred->getBlockID()]);
 905   BlockInfo *PredInfo = &BBInfo[Pred->getBlockID()];
 906   assert(PredInfo->UnprocessedSuccessors > 0);
 907
 908   if (--PredInfo->UnprocessedSuccessors == 0)
 909     mergeEntryMap(std::move(PredInfo->ExitMap));
 910   else
 911     mergeEntryMap(PredInfo->ExitMap.clone());
 912
 913   ++CurrentBlockInfo->ProcessedPredecessors;
 914 }
 915
 916 void SExprBuilder::handlePredecessorBackEdge(const CFGBlock *Pred) {
 917   mergeEntryMapBackEdge();
 918 }
 919
 920 void SExprBuilder::enterCFGBlockBody(const CFGBlock *B) {
 921   // The merge*() methods have created arguments.
 922   // Push those arguments onto the basic block.
 923   CurrentBB->arguments().reserve(
 924     static_cast<unsigned>(CurrentArguments.size()), Arena);
 925   for (auto *A : CurrentArguments)
 926     CurrentBB->addArgument(A);
 927 }
 928
 929 void SExprBuilder::handleStatement(const Stmt *S) {
 930   til::SExpr *E = translate(S, nullptr);
 931   addStatement(E, S);
 932 }
 933
 934 void SExprBuilder::handleDestructorCall(const VarDecl *VD,
 935                                         const CXXDestructorDecl *DD) {
 936   til::SExpr *Sf = new (Arena) til::LiteralPtr(VD);
 937   til::SExpr *Dr = new (Arena) til::LiteralPtr(DD);
 938   til::SExpr *Ap = new (Arena) til::Apply(Dr, Sf);
 939   til::SExpr *E = new (Arena) til::Call(Ap);
 940   addStatement(E, nullptr);
 941 }
 942
 943 void SExprBuilder::exitCFGBlockBody(const CFGBlock *B) {
 944   CurrentBB->instructions().reserve(
 945     static_cast<unsigned>(CurrentInstructions.size()), Arena);
 946   for (auto *V : CurrentInstructions)
 947     CurrentBB->addInstruction(V);
 948
 949   // Create an appropriate terminator
 950   unsigned N = B->succ_size();
 951   auto It = B->succ_begin();
 952   if (N == 1) {
 953     til::BasicBlock *BB = *It ? lookupBlock(*It) : nullptr;
 954     // TODO: set index
 955     unsigned Idx = BB ? BB->findPredecessorIndex(CurrentBB) : 0;
 956     auto *Tm = new (Arena) til::Goto(BB, Idx);
 957     CurrentBB->setTerminator(Tm);
 958   }
 959   else if (N == 2) {
 960     til::SExpr *C = translate(B->getTerminatorCondition(true), nullptr);
 961     til::BasicBlock *BB1 = *It ? lookupBlock(*It) : nullptr;
 962     ++It;
 963     til::BasicBlock *BB2 = *It ? lookupBlock(*It) : nullptr;
 964     // FIXME: make sure these aren't critical edges.
 965     auto *Tm = new (Arena) til::Branch(C, BB1, BB2);
 966     CurrentBB->setTerminator(Tm);
 967   }
 968 }
 969
 970 void SExprBuilder::handleSuccessor(const CFGBlock *Succ) {
 971   ++CurrentBlockInfo->UnprocessedSuccessors;
 972 }
 973
 974 void SExprBuilder::handleSuccessorBackEdge(const CFGBlock *Succ) {
 975   mergePhiNodesBackEdge(Succ);
 976   ++BBInfo[Succ->getBlockID()].ProcessedPredecessors;
 977 }
 978
 979 void SExprBuilder::exitCFGBlock(const CFGBlock *B) {
 980   CurrentArguments.clear();
 981   CurrentInstructions.clear();
 982   CurrentBlockInfo->ExitMap = std::move(CurrentLVarMap);
 983   CurrentBB = nullptr;
 984   CurrentBlockInfo = nullptr;
 985 }
 986
 987 void SExprBuilder::exitCFG(const CFGBlock *Last) {
 988   for (auto *Ph : IncompleteArgs) {
 989     if (Ph->status() == til::Phi::PH_Incomplete)
 990       simplifyIncompleteArg(Ph);
 991   }
 992
 993   CurrentArguments.clear();
 994   CurrentInstructions.clear();
 995   IncompleteArgs.clear();
 996 }
 997
 998 #ifndef NDEBUG
 999 namespace {
1000
1001 class TILPrinter :
1002     public til::PrettyPrinter<TILPrinter, llvm::raw_ostream> {};
1003
1004 } // namespace
1005
1006 namespace clang {
1007 namespace threadSafety {
1008
1009 void printSCFG(CFGWalker &Walker) {
1010   llvm::BumpPtrAllocator Bpa;
1011   til::MemRegionRef Arena(&Bpa);
1012   SExprBuilder SxBuilder(Arena);
1013   til::SCFG *Scfg = SxBuilder.buildCFG(Walker);
1014   TILPrinter::print(Scfg, llvm::errs());
1015 }
1016
1017 } // namespace threadSafety
1018 } // namespace clang
1019 #endif // NDEBUG