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//== 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;
typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D);
/// 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();
const BlockPointerType *BPT = Ty->getAs<BlockPointerType>();
if (!BPT)
return 0;
// 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 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();
// }
//
DeclRefExpr *DR = DeclRefExpr::CreateEmpty(C, false, false, false, false);
DR->setDecl(const_cast<ParmVarDecl*>(PV));
DR->setValueKind(VK_LValue);
ImplicitCastExpr *ICE = ImplicitCastExpr::Create(C, Ty, CK_LValueToRValue,
DR, 0, VK_RValue);
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)
.Default(NULL);
if (FF) {
Val = FF(C, D);
}
return Val.getValue();
}
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