vendor/clang/clang-release_32-r168974

1 files changed, 374 insertions, 0 deletions

diff --git a/lib/Analysis/BodyFarm.cpp b/lib/Analysis/BodyFarm.cpp
new file mode 100644
index 000000000000..794ff9cc2bb1
--- /dev/null
+++ b/lib/Analysis/BodyFarm.cpp
@@ -0,0 +1,374 @@
+//== 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 "clang/AST/ExprObjC.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 BinaryOperator representing a comparison.
+  BinaryOperator *makeComparison(const Expr *LHS, const Expr *RHS,
+                                 BinaryOperator::Opcode Op);
+  
+  /// Create a new compound stmt using the provided statements.
+  CompoundStmt *makeCompound(ArrayRef<Stmt*>);
+  
+  /// 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.
+  Expr *makeIntegralCast(const Expr *Arg, QualType Ty);
+  
+  /// Create an implicit cast to a builtin boolean type.
+  ImplicitCastExpr *makeIntegralCastToBoolean(const Expr *Arg);
+  
+  // Create an implicit cast for lvalue-to-rvaluate conversions.
+  ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty);
+  
+  /// Create an Objective-C bool literal.
+  ObjCBoolLiteralExpr *makeObjCBool(bool Val);
+  
+  /// Create a Return statement.
+  ReturnStmt *makeReturn(const Expr *RetVal);
+  
+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(), false);
+}
+
+BinaryOperator *ASTMaker::makeComparison(const Expr *LHS, const Expr *RHS,
+                                         BinaryOperator::Opcode Op) {
+  assert(BinaryOperator::isLogicalOp(Op) ||
+         BinaryOperator::isComparisonOp(Op));
+  return new (C) BinaryOperator(const_cast<Expr*>(LHS),
+                                const_cast<Expr*>(RHS),
+                                Op,
+                                C.getLogicalOperationType(),
+                                VK_RValue,
+                                OK_Ordinary, SourceLocation(), false);
+}
+
+CompoundStmt *ASTMaker::makeCompound(ArrayRef<Stmt *> Stmts) {
+  return new (C) CompoundStmt(C, const_cast<Stmt**>(Stmts.data()),
+                              Stmts.size(),
+                              SourceLocation(), 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);
+}
+
+Expr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) {
+  if (Arg->getType() == Ty)
+    return const_cast<Expr*>(Arg);
+  
+  return ImplicitCastExpr::Create(C, Ty, CK_IntegralCast,
+                                  const_cast<Expr*>(Arg), 0, VK_RValue);
+}
+
+ImplicitCastExpr *ASTMaker::makeIntegralCastToBoolean(const Expr *Arg) {
+  return ImplicitCastExpr::Create(C, C.BoolTy, CK_IntegralToBoolean,
+                                  const_cast<Expr*>(Arg), 0, VK_RValue);
+}
+
+ObjCBoolLiteralExpr *ASTMaker::makeObjCBool(bool Val) {
+  QualType Ty = C.getBOOLDecl() ? C.getBOOLType() : C.ObjCBuiltinBoolTy;
+  return new (C) ObjCBoolLiteralExpr(Val, Ty, SourceLocation());
+}
+
+ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) {
+  return new (C) ReturnStmt(SourceLocation(), const_cast<Expr*>(RetVal), 0);
+}
+
+//===----------------------------------------------------------------------===//
+// 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 = M.makeCompound(ArrayRef<Stmt*>(Stmts, 2));
+  
+  // (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;
+}
+
+static Stmt *create_OSAtomicCompareAndSwap(ASTContext &C, const FunctionDecl *D)
+{
+  // There are exactly 3 arguments.
+  if (D->param_size() != 3)
+    return 0;
+  
+  // Body for:
+  //   if (oldValue == *theValue) {
+  //    *theValue = newValue;
+  //    return YES;
+  //   }
+  //   else return NO;
+  
+  QualType ResultTy = D->getResultType();
+  bool isBoolean = ResultTy->isBooleanType();
+  if (!isBoolean && !ResultTy->isIntegralType(C))
+    return 0;
+  
+  const ParmVarDecl *OldValue = D->getParamDecl(0);
+  QualType OldValueTy = OldValue->getType();
+
+  const ParmVarDecl *NewValue = D->getParamDecl(1);
+  QualType NewValueTy = NewValue->getType();
+  
+  assert(OldValueTy == NewValueTy);
+  
+  const ParmVarDecl *TheValue = D->getParamDecl(2);
+  QualType TheValueTy = TheValue->getType();
+  const PointerType *PT = TheValueTy->getAs<PointerType>();
+  if (!PT)
+    return 0;
+  QualType PointeeTy = PT->getPointeeType();
+  
+  ASTMaker M(C);
+  // Construct the comparison.
+  Expr *Comparison =
+    M.makeComparison(
+      M.makeLvalueToRvalue(M.makeDeclRefExpr(OldValue), OldValueTy),
+      M.makeLvalueToRvalue(
+        M.makeDereference(
+          M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
+          PointeeTy),
+        PointeeTy),
+      BO_EQ);
+
+  // Construct the body of the IfStmt.
+  Stmt *Stmts[2];
+  Stmts[0] =
+    M.makeAssignment(
+      M.makeDereference(
+        M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
+        PointeeTy),
+      M.makeLvalueToRvalue(M.makeDeclRefExpr(NewValue), NewValueTy),
+      NewValueTy);
+  
+  Expr *BoolVal = M.makeObjCBool(true);
+  Expr *RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
+                           : M.makeIntegralCast(BoolVal, ResultTy);
+  Stmts[1] = M.makeReturn(RetVal);
+  CompoundStmt *Body = M.makeCompound(ArrayRef<Stmt*>(Stmts, 2));
+  
+  // Construct the else clause.
+  BoolVal = M.makeObjCBool(false);
+  RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
+                     : M.makeIntegralCast(BoolVal, ResultTy);
+  Stmt *Else = M.makeReturn(RetVal);
+  
+  /// Construct the If.
+  Stmt *If =
+    new (C) IfStmt(C, SourceLocation(), 0, Comparison, Body,
+                   SourceLocation(), Else);
+  
+  return If;  
+}
+
+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;
+
+  if (Name.startswith("OSAtomicCompareAndSwap") ||
+      Name.startswith("objc_atomicCompareAndSwap")) {
+    FF = create_OSAtomicCompareAndSwap;
+  }
+  else {
+    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();
+}
+