1 files changed, 91 insertions, 0 deletions
diff --git a/lib/Analysis/BodyFarm.cpp b/lib/Analysis/BodyFarm.cpp
new file mode 100644
index 0000000000..217f607d56
--- /dev/null
+++ b/lib/Analysis/BodyFarm.cpp
@@ -0,0 +1,91 @@
+//== 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();
+}
+