| //== BodyFarm.cpp - Factory for conjuring up fake bodies ----------*- C++ -*-// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // BodyFarm is a factory for creating faux implementations for functions/methods |
| // for analysis purposes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ADT/StringSwitch.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/Decl.h" |
| #include "BodyFarm.h" |
| |
| using namespace clang; |
| |
| //===----------------------------------------------------------------------===// |
| // Helper creation functions for constructing faux ASTs. |
| //===----------------------------------------------------------------------===// |
| |
| static bool isDispatchBlock(QualType Ty) { |
| // Is it a block pointer? |
| const BlockPointerType *BPT = Ty->getAs<BlockPointerType>(); |
| if (!BPT) |
| return false; |
| |
| // Check if the block pointer type takes no arguments and |
| // returns void. |
| const FunctionProtoType *FT = |
| BPT->getPointeeType()->getAs<FunctionProtoType>(); |
| if (!FT || !FT->getResultType()->isVoidType() || |
| FT->getNumArgs() != 0) |
| return false; |
| |
| return true; |
| } |
| |
| namespace { |
| class ASTMaker { |
| public: |
| ASTMaker(ASTContext &C) : C(C) {} |
| |
| /// Create a new BinaryOperator representing a simple assignment. |
| BinaryOperator *makeAssignment(const Expr *LHS, const Expr *RHS, QualType Ty); |
| |
| /// Create a new DeclRefExpr for the referenced variable. |
| DeclRefExpr *makeDeclRefExpr(const VarDecl *D); |
| |
| /// Create a new UnaryOperator representing a dereference. |
| UnaryOperator *makeDereference(const Expr *Arg, QualType Ty); |
| |
| /// Create an implicit cast for an integer conversion. |
| ImplicitCastExpr *makeIntegralCast(const Expr *Arg, QualType Ty); |
| |
| // Create an implicit cast for lvalue-to-rvaluate conversions. |
| ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty); |
| |
| private: |
| ASTContext &C; |
| }; |
| } |
| |
| BinaryOperator *ASTMaker::makeAssignment(const Expr *LHS, const Expr *RHS, |
| QualType Ty) { |
| return new (C) BinaryOperator(const_cast<Expr*>(LHS), const_cast<Expr*>(RHS), |
| BO_Assign, Ty, VK_RValue, |
| OK_Ordinary, SourceLocation()); |
| } |
| |
| DeclRefExpr *ASTMaker::makeDeclRefExpr(const VarDecl *D) { |
| DeclRefExpr *DR = |
| DeclRefExpr::Create(/* Ctx = */ C, |
| /* QualifierLoc = */ NestedNameSpecifierLoc(), |
| /* TemplateKWLoc = */ SourceLocation(), |
| /* D = */ const_cast<VarDecl*>(D), |
| /* isEnclosingLocal = */ false, |
| /* NameLoc = */ SourceLocation(), |
| /* T = */ D->getType(), |
| /* VK = */ VK_LValue); |
| return DR; |
| } |
| |
| UnaryOperator *ASTMaker::makeDereference(const Expr *Arg, QualType Ty) { |
| return new (C) UnaryOperator(const_cast<Expr*>(Arg), UO_Deref, Ty, |
| VK_LValue, OK_Ordinary, SourceLocation()); |
| } |
| |
| ImplicitCastExpr *ASTMaker::makeLvalueToRvalue(const Expr *Arg, QualType Ty) { |
| return ImplicitCastExpr::Create(C, Ty, CK_LValueToRValue, |
| const_cast<Expr*>(Arg), 0, VK_RValue); |
| } |
| |
| ImplicitCastExpr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) { |
| return ImplicitCastExpr::Create(C, Ty, CK_IntegralCast, |
| const_cast<Expr*>(Arg), 0, VK_RValue); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Creation functions for faux ASTs. |
| //===----------------------------------------------------------------------===// |
| |
| typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D); |
| |
| /// Create a fake body for dispatch_once. |
| static Stmt *create_dispatch_once(ASTContext &C, const FunctionDecl *D) { |
| // Check if we have at least two parameters. |
| if (D->param_size() != 2) |
| return 0; |
| |
| // Check if the first parameter is a pointer to integer type. |
| const ParmVarDecl *Predicate = D->getParamDecl(0); |
| QualType PredicateQPtrTy = Predicate->getType(); |
| const PointerType *PredicatePtrTy = PredicateQPtrTy->getAs<PointerType>(); |
| if (!PredicatePtrTy) |
| return 0; |
| QualType PredicateTy = PredicatePtrTy->getPointeeType(); |
| if (!PredicateTy->isIntegerType()) |
| return 0; |
| |
| // Check if the second parameter is the proper block type. |
| const ParmVarDecl *Block = D->getParamDecl(1); |
| QualType Ty = Block->getType(); |
| if (!isDispatchBlock(Ty)) |
| return 0; |
| |
| // Everything checks out. Create a fakse body that checks the predicate, |
| // sets it, and calls the block. Basically, an AST dump of: |
| // |
| // void dispatch_once(dispatch_once_t *predicate, dispatch_block_t block) { |
| // if (!*predicate) { |
| // *predicate = 1; |
| // block(); |
| // } |
| // } |
| |
| ASTMaker M(C); |
| |
| // (1) Create the call. |
| DeclRefExpr *DR = M.makeDeclRefExpr(Block); |
| ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty); |
| CallExpr *CE = new (C) CallExpr(C, ICE, ArrayRef<Expr*>(), C.VoidTy, |
| VK_RValue, SourceLocation()); |
| |
| // (2) Create the assignment to the predicate. |
| IntegerLiteral *IL = |
| IntegerLiteral::Create(C, llvm::APInt(C.getTypeSize(C.IntTy), (uint64_t) 1), |
| C.IntTy, SourceLocation()); |
| BinaryOperator *B = |
| M.makeAssignment( |
| M.makeDereference( |
| M.makeLvalueToRvalue( |
| M.makeDeclRefExpr(Predicate), PredicateQPtrTy), |
| PredicateTy), |
| M.makeIntegralCast(IL, PredicateTy), |
| PredicateTy); |
| |
| // (3) Create the compound statement. |
| Stmt *Stmts[2]; |
| Stmts[0] = B; |
| Stmts[1] = CE; |
| CompoundStmt *CS = new (C) CompoundStmt(C, Stmts, 2, SourceLocation(), |
| SourceLocation()); |
| |
| // (4) Create the 'if' condition. |
| ImplicitCastExpr *LValToRval = |
| M.makeLvalueToRvalue( |
| M.makeDereference( |
| M.makeLvalueToRvalue( |
| M.makeDeclRefExpr(Predicate), |
| PredicateQPtrTy), |
| PredicateTy), |
| PredicateTy); |
| |
| UnaryOperator *UO = new (C) UnaryOperator(LValToRval, UO_LNot, C.IntTy, |
| VK_RValue, OK_Ordinary, |
| SourceLocation()); |
| |
| // (5) Create the 'if' statement. |
| IfStmt *If = new (C) IfStmt(C, SourceLocation(), 0, UO, CS); |
| return If; |
| } |
| |
| /// Create a fake body for dispatch_sync. |
| static Stmt *create_dispatch_sync(ASTContext &C, const FunctionDecl *D) { |
| // Check if we have at least two parameters. |
| if (D->param_size() != 2) |
| return 0; |
| |
| // Check if the second parameter is a block. |
| const ParmVarDecl *PV = D->getParamDecl(1); |
| QualType Ty = PV->getType(); |
| if (!isDispatchBlock(Ty)) |
| return 0; |
| |
| // Everything checks out. Create a fake body that just calls the block. |
| // This is basically just an AST dump of: |
| // |
| // void dispatch_sync(dispatch_queue_t queue, void (^block)(void)) { |
| // block(); |
| // } |
| // |
| ASTMaker M(C); |
| DeclRefExpr *DR = M.makeDeclRefExpr(PV); |
| ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty); |
| CallExpr *CE = new (C) CallExpr(C, ICE, ArrayRef<Expr*>(), C.VoidTy, |
| VK_RValue, SourceLocation()); |
| return CE; |
| } |
| |
| Stmt *BodyFarm::getBody(const FunctionDecl *D) { |
| D = D->getCanonicalDecl(); |
| |
| llvm::Optional<Stmt *> &Val = Bodies[D]; |
| if (Val.hasValue()) |
| return Val.getValue(); |
| |
| Val = 0; |
| |
| if (D->getIdentifier() == 0) |
| return 0; |
| |
| StringRef Name = D->getName(); |
| if (Name.empty()) |
| return 0; |
| |
| FunctionFarmer FF = |
| llvm::StringSwitch<FunctionFarmer>(Name) |
| .Case("dispatch_sync", create_dispatch_sync) |
| .Case("dispatch_once", create_dispatch_once) |
| .Default(NULL); |
| |
| if (FF) { |
| Val = FF(C, D); |
| } |
| |
| return Val.getValue(); |
| } |
| |