[ObjCARC Annotations] Added support for displaying the state of pointers at the bottom/top of BBs of the ARC dataflow analysis for both bottomup and topdown analyses.

This will allow for verification and analysis of the merge function of
the data flow analyses in the ARC optimizer.

The actual implementation of this feature is by introducing calls to
the functions llvm.arc.annotation.{bottomup,topdown}.{bbstart,bbend}
which are only declared. Each such call takes in a pointer to a global
with the same name as the pointer whose provenance is being tracked and
a pointer whose name is one of our Sequence states and points to a
string that contains the same name.

To ensure that the optimizer does not consider these annotations in any
way, I made it so that the annotations are considered to be of IC_None
type.

A test case is included for this commit and the previous
ObjCARCAnnotation commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177952 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 139 insertions, 4 deletions

diff --git a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index d13baf3db8..a21d92e48f 100644
--- a/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -33,6 +33,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Support/Debug.h"
@@ -763,14 +764,18 @@ static MDString *AppendMDNodeToSourcePtr(unsigned NodeId,
   return Hash;
 }
 
+static std::string SequenceToString(Sequence A) {
+  std::string str;
+  raw_string_ostream os(str);
+  os << A;
+  return os.str();
+}
+
 /// Helper function to change a Sequence into a String object using our overload
 /// for raw_ostream so we only have printing code in one location.
 static MDString *SequenceToMDString(LLVMContext &Context,
                                     Sequence A) {
-  std::string str;
-  raw_string_ostream os(str);
-  os << A;
-  return MDString::get(Context, os.str());
+  return MDString::get(Context, SequenceToString(A));
 }
 
 /// A simple function to generate a MDNode which describes the change in state
@@ -793,6 +798,79 @@ static void AppendMDNodeToInstForPtr(unsigned NodeId,
   Inst->setMetadata(NodeId, Node);
 }
 
+/// Add to the beginning of the basic block llvm.ptr.annotations which show the
+/// state of a pointer at the entrance to a basic block.
+static void GenerateARCBBEntranceAnnotation(const char *Name, BasicBlock *BB,
+                                            Value *Ptr, Sequence Seq) {
+  Module *M = BB->getParent()->getParent();
+  LLVMContext &C = M->getContext();
+  Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+  Type *I8XX = PointerType::getUnqual(I8X);
+  Type *Params[] = {I8XX, I8XX};
+  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C),
+                                        ArrayRef<Type*>(Params, 2),
+                                        /*isVarArg=*/false);
+  Constant *Callee = M->getOrInsertFunction(Name, FTy);
+  
+  IRBuilder<> Builder(BB, BB->getFirstInsertionPt());  
+  
+  Value *PtrName;
+  StringRef Tmp = Ptr->getName();
+  if (0 == (PtrName = M->getGlobalVariable(Tmp, true))) {
+    Value *ActualPtrName = Builder.CreateGlobalStringPtr(Tmp,
+                                                         Tmp + "_STR");
+    PtrName = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage,
+                                 cast<Constant>(ActualPtrName), Tmp); 
+  }
+
+  Value *S;
+  std::string SeqStr = SequenceToString(Seq);
+  if (0 == (S = M->getGlobalVariable(SeqStr, true))) {
+    Value *ActualPtrName = Builder.CreateGlobalStringPtr(SeqStr,
+                                                         SeqStr + "_STR");
+    S = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage,
+                           cast<Constant>(ActualPtrName), SeqStr);
+  }
+
+  Builder.CreateCall2(Callee, PtrName, S);
+}
+
+/// Add to the end of the basic block llvm.ptr.annotations which show the state
+/// of the pointer at the bottom of the basic block.
+static void GenerateARCBBTerminatorAnnotation(const char *Name, BasicBlock *BB,
+                                              Value *Ptr, Sequence Seq) {
+  Module *M = BB->getParent()->getParent();
+  LLVMContext &C = M->getContext();
+  Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
+  Type *I8XX = PointerType::getUnqual(I8X);
+  Type *Params[] = {I8XX, I8XX};
+  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C),
+                                        ArrayRef<Type*>(Params, 2),
+                                        /*isVarArg=*/false);
+  Constant *Callee = M->getOrInsertFunction(Name, FTy);
+  
+  IRBuilder<> Builder(BB, llvm::prior(BB->end()));  
+  
+  Value *PtrName;
+  StringRef Tmp = Ptr->getName();
+  if (0 == (PtrName = M->getGlobalVariable(Tmp, true))) {
+    Value *ActualPtrName = Builder.CreateGlobalStringPtr(Tmp,
+                                                         Tmp + "_STR");
+    PtrName = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage,
+                                 cast<Constant>(ActualPtrName), Tmp); 
+  }
+
+  Value *S;
+  std::string SeqStr = SequenceToString(Seq);
+  if (0 == (S = M->getGlobalVariable(SeqStr, true))) {
+    Value *ActualPtrName = Builder.CreateGlobalStringPtr(SeqStr,
+                                                         SeqStr + "_STR");
+    S = new GlobalVariable(*M, I8X, true, GlobalVariable::InternalLinkage,
+                           cast<Constant>(ActualPtrName), SeqStr);
+  }
+  Builder.CreateCall2(Callee, PtrName, S);  
+}
+
 /// Adds a source annotation to pointer and a state change annotation to Inst
 /// referencing the source annotation and the old/new state of pointer.
 static void GenerateARCAnnotation(unsigned InstMDId,
@@ -1816,7 +1894,22 @@ ObjCARCOpt::VisitBottomUp(BasicBlock *BB,
       assert(I != BBStates.end());
       MyStates.MergeSucc(I->second);
     }
+  }  
+
+#ifdef ARC_ANNOTATIONS
+  if (EnableARCAnnotations) {
+    // If ARC Annotations are enabled, output the current state of pointers at the
+    // bottom of the basic block.
+    for(BBState::ptr_const_iterator I = MyStates.bottom_up_ptr_begin(),
+          E = MyStates.bottom_up_ptr_end(); I != E; ++I) {
+      Value *Ptr = const_cast<Value*>(I->first);
+      Sequence Seq = I->second.GetSeq();
+      GenerateARCBBTerminatorAnnotation("llvm.arc.annotation.bottomup.bbend",
+                                        BB, Ptr, Seq);
+    }
   }
+#endif
+
 
   // Visit all the instructions, bottom-up.
   for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; --I) {
@@ -1841,6 +1934,20 @@ ObjCARCOpt::VisitBottomUp(BasicBlock *BB,
       NestingDetected |= VisitInstructionBottomUp(II, BB, Retains, MyStates);
   }
 
+#ifdef ARC_ANNOTATIONS
+  if (EnableARCAnnotations) {
+    // If ARC Annotations are enabled, output the current state of pointers at the
+    // top of the basic block.
+    for(BBState::ptr_const_iterator I = MyStates.bottom_up_ptr_begin(),
+          E = MyStates.bottom_up_ptr_end(); I != E; ++I) {
+      Value *Ptr = const_cast<Value*>(I->first);
+      Sequence Seq = I->second.GetSeq();
+      GenerateARCBBEntranceAnnotation("llvm.arc.annotation.bottomup.bbstart",
+                                      BB, Ptr, Seq);
+    }
+  }
+#endif
+
   return NestingDetected;
 }
 
@@ -2012,6 +2119,20 @@ ObjCARCOpt::VisitTopDown(BasicBlock *BB,
     }
   }
 
+#ifdef ARC_ANNOTATIONS
+  if (EnableARCAnnotations) {
+    // If ARC Annotations are enabled, output the current state of pointers at the
+    // top of the basic block.
+    for(BBState::ptr_const_iterator I = MyStates.top_down_ptr_begin(),
+          E = MyStates.top_down_ptr_end(); I != E; ++I) {
+      Value *Ptr = const_cast<Value*>(I->first);
+      Sequence Seq = I->second.GetSeq();
+      GenerateARCBBEntranceAnnotation("llvm.arc.annotation.topdown.bbstart",
+                                      BB, Ptr, Seq);
+    }
+  }
+#endif
+
   // Visit all the instructions, top-down.
   for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
     Instruction *Inst = I;
@@ -2021,6 +2142,20 @@ ObjCARCOpt::VisitTopDown(BasicBlock *BB,
     NestingDetected |= VisitInstructionTopDown(Inst, Releases, MyStates);
   }
 
+#ifdef ARC_ANNOTATIONS
+  if (EnableARCAnnotations) {
+    // If ARC Annotations are enabled, output the current state of pointers at the
+    // bottom of the basic block.
+    for(BBState::ptr_const_iterator I = MyStates.top_down_ptr_begin(),
+          E = MyStates.top_down_ptr_end(); I != E; ++I) {
+      Value *Ptr = const_cast<Value*>(I->first);
+      Sequence Seq = I->second.GetSeq();
+      GenerateARCBBTerminatorAnnotation("llvm.arc.annotation.topdown.bbend",
+                                        BB, Ptr, Seq);
+    }
+  }
+#endif
+
   CheckForCFGHazards(BB, BBStates, MyStates);
   return NestingDetected;
 }