[asan] remove the code for --asan-merge-callbacks as it appears to be a bad idea. (partly related to Bug 13225)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161757 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 78 deletions

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 3368026..bf35eac 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -86,9 +86,6 @@ static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
 static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
        cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
        cl::Hidden, cl::init(true));
-static cl::opt<bool> ClMergeCallbacks("asan-merge-callbacks",
-       cl::desc("merge __asan_report_ callbacks to create fewer BBs"),
-       cl::Hidden, cl::init(false));
 // This flag limits the number of instructions to be instrumented
 // in any given BB. Normally, this should be set to unlimited (INT_MAX),
 // but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
@@ -145,24 +142,11 @@ static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
 
 namespace {
 
-/// When the crash callbacks are merged, they receive some amount of arguments
-/// that are merged in a PHI node. This struct represents arguments from one
-/// call site.
-struct CrashArg {
-  Value *Arg1;
-  Value *Arg2;
-};
-
 /// An object of this type is created while instrumenting every function.
 struct AsanFunctionContext {
-  AsanFunctionContext(Function &Function) : F(Function), CrashBlock() { }
+  AsanFunctionContext(Function &Function) : F(Function) { }
 
   Function &F;
-  // These are initially zero. If we require at least one call to
-  // __asan_report_{read,write}{1,2,4,8,16}, an appropriate BB is created.
-  BasicBlock *CrashBlock[2][kNumberOfAccessSizes];
-  typedef  SmallVector<CrashArg, 8> CrashArgsVec;
-  CrashArgsVec CrashArgs[2][kNumberOfAccessSizes];
 };
 
 /// AddressSanitizer: instrument the code in module to find memory bugs.
@@ -457,34 +441,12 @@ void AddressSanitizer::instrumentAddress(AsanFunctionContext &AFC,
 
   Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
 
-  BasicBlock *CrashBlock = 0;
-  if (ClMergeCallbacks) {
-    size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
-    BasicBlock **Cached = &AFC.CrashBlock[IsWrite][AccessSizeIndex];
-    if (!*Cached) {
-      std::string BBName("crash_bb-");
-      BBName += (IsWrite ? "w-" : "r-") + itostr(1 << AccessSizeIndex);
-      BasicBlock *BB = BasicBlock::Create(*C, BBName, &AFC.F);
-      new UnreachableInst(*C, BB);
-      *Cached = BB;
-    }
-    CrashBlock = *Cached;
-    // We need to pass the PC as the second parameter to __asan_report_*.
-    // There are few problems:
-    //  - Some architectures (e.g. x86_32) don't have a cheap way to get the PC.
-    //  - LLVM doesn't have the appropriate intrinsic.
-    // For now, put a random number into the PC, just to allow experiments.
-    Value *PC = ConstantInt::get(IntptrTy, rand());
-    CrashArg Arg = {AddrLong, PC};
-    AFC.CrashArgs[IsWrite][AccessSizeIndex].push_back(Arg);
-  } else {
-    CrashBlock = BasicBlock::Create(*C, "crash_bb", &AFC.F);
-    new UnreachableInst(*C, CrashBlock);
-    size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
-    Instruction *Crash =
-        generateCrashCode(CrashBlock, AddrLong, 0, IsWrite, AccessSizeIndex);
-    Crash->setDebugLoc(OrigIns->getDebugLoc());
-  }
+  BasicBlock *CrashBlock = BasicBlock::Create(*C, "crash_bb", &AFC.F);
+  new UnreachableInst(*C, CrashBlock);
+  size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
+  Instruction *Crash =
+      generateCrashCode(CrashBlock, AddrLong, 0, IsWrite, AccessSizeIndex);
+  Crash->setDebugLoc(OrigIns->getDebugLoc());
 
   size_t Granularity = 1 << MappingScale;
   if (TypeSize < 8 * Granularity) {
@@ -694,12 +656,7 @@ bool AddressSanitizer::runOnModule(Module &M) {
       std::string FunctionName = std::string(kAsanReportErrorTemplate) +
           (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
       // If we are merging crash callbacks, they have two parameters.
-      if (ClMergeCallbacks)
-        AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast<Function>(
-          M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy,
-                                IntptrTy, NULL));
-      else
-        AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast<Function>(
+      AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast<Function>(
           M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
     }
   }
@@ -845,33 +802,6 @@ bool AddressSanitizer::handleFunction(Module &M, Function &F) {
     NumInstrumented++;
   }
 
-  // Create PHI nodes and crash callbacks if we are merging crash callbacks.
-  if (NumInstrumented) {
-    for (size_t IsWrite = 0; IsWrite <= 1; IsWrite++) {
-      for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
-           AccessSizeIndex++) {
-        BasicBlock *BB = AFC.CrashBlock[IsWrite][AccessSizeIndex];
-        if (!BB) continue;
-        assert(ClMergeCallbacks);
-        AsanFunctionContext::CrashArgsVec &Args =
-            AFC.CrashArgs[IsWrite][AccessSizeIndex];
-        IRBuilder<> IRB(BB->getFirstNonPHI());
-        size_t n = Args.size();
-        PHINode *PN1 = IRB.CreatePHI(IntptrTy, n);
-        PHINode *PN2 = IRB.CreatePHI(IntptrTy, n);
-        // We need to match crash parameters and the predecessors.
-        for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
-             PI != PE; ++PI) {
-          n--;
-          PN1->addIncoming(Args[n].Arg1, *PI);
-          PN2->addIncoming(Args[n].Arg2, *PI);
-        }
-        assert(n == 0);
-        generateCrashCode(BB, PN1, PN2, IsWrite, AccessSizeIndex);
-      }
-    }
-  }
-
   DEBUG(dbgs() << F);
 
   bool ChangedStack = poisonStackInFunction(M, F);