Add a 'dynamic' parameter to the objectsize intrinsic

This is meant to be used with clang's __builtin_dynamic_object_size.
When 'true' is passed to this parameter, the intrinsic has the
potential to be folded into instructions that will be evaluated
at run time. When 'false', the objectsize intrinsic behaviour is
unchanged.

rdar://32212419

Differential revision: https://reviews.llvm.org/D56761

llvm-svn: 352664

7 files changed, 48 insertions, 26 deletions

diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 64643535f64..56332bb5fe8 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -441,10 +441,10 @@ bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
   return true;
 }
 
-ConstantInt *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
-                                       const DataLayout &DL,
-                                       const TargetLibraryInfo *TLI,
-                                       bool MustSucceed) {
+Value *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
+                                 const DataLayout &DL,
+                                 const TargetLibraryInfo *TLI,
+                                 bool MustSucceed) {
   assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
          "ObjectSize must be a call to llvm.objectsize!");
 
@@ -461,13 +461,35 @@ ConstantInt *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
   EvalOptions.NullIsUnknownSize =
       cast<ConstantInt>(ObjectSize->getArgOperand(2))->isOne();
 
-  // FIXME: Does it make sense to just return a failure value if the size won't
-  // fit in the output and `!MustSucceed`?
-  uint64_t Size;
   auto *ResultType = cast<IntegerType>(ObjectSize->getType());
-  if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, EvalOptions) &&
-      isUIntN(ResultType->getBitWidth(), Size))
-    return ConstantInt::get(ResultType, Size);
+  bool StaticOnly = cast<ConstantInt>(ObjectSize->getArgOperand(3))->isZero();
+  if (StaticOnly) {
+    // FIXME: Does it make sense to just return a failure value if the size won't
+    // fit in the output and `!MustSucceed`?
+    uint64_t Size;
+    if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, EvalOptions) &&
+        isUIntN(ResultType->getBitWidth(), Size))
+      return ConstantInt::get(ResultType, Size);
+  } else {
+    LLVMContext &Ctx = ObjectSize->getFunction()->getContext();
+    ObjectSizeOffsetEvaluator Eval(DL, TLI, Ctx, EvalOptions);
+    SizeOffsetEvalType SizeOffsetPair =
+        Eval.compute(ObjectSize->getArgOperand(0));
+
+    if (SizeOffsetPair != ObjectSizeOffsetEvaluator::unknown()) {
+      IRBuilder<TargetFolder> Builder(Ctx, TargetFolder(DL));
+      Builder.SetInsertPoint(ObjectSize);
+
+      // If we've outside the end of the object, then we can always access
+      // exactly 0 bytes.
+      Value *ResultSize =
+          Builder.CreateSub(SizeOffsetPair.first, SizeOffsetPair.second);
+      Value *UseZero =
+          Builder.CreateICmpULT(SizeOffsetPair.first, SizeOffsetPair.second);
+      return Builder.CreateSelect(UseZero, ConstantInt::get(ResultType, 0),
+                                  ResultSize);
+    }
+  }
 
   if (!MustSucceed)
     return nullptr;
@@ -742,9 +764,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
 
 ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(
     const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context,
-    bool RoundToAlign)
+    ObjectSizeOpts EvalOpts)
     : DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)),
-      RoundToAlign(RoundToAlign) {
+      EvalOpts(EvalOpts) {
   // IntTy and Zero must be set for each compute() since the address space may
   // be different for later objects.
 }
@@ -773,10 +795,7 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
 }
 
 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
-  ObjectSizeOpts ObjSizeOptions;
-  ObjSizeOptions.RoundToAlign = RoundToAlign;
-
-  ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, ObjSizeOptions);
+  ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, EvalOpts);
   SizeOffsetType Const = Visitor.compute(V);
   if (Visitor.bothKnown(Const))
     return std::make_pair(ConstantInt::get(Context, Const.first),
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 486290d09a4..24c926c01a5 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1705,7 +1705,7 @@ bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool &ModifiedDT) {
     default: break;
     case Intrinsic::objectsize: {
       // Lower all uses of llvm.objectsize.*
-      ConstantInt *RetVal =
+      Value *RetVal =
           lowerObjectSizeCall(II, *DL, TLInfo, /*MustSucceed=*/true);
 
       resetIteratorIfInvalidatedWhileCalling(BB, [&]() {
diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index 396a425aef6..aa132fa86d5 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -3459,8 +3459,10 @@ void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
     Value *NullIsUnknownSize = CI->getNumArgOperands() == 2
                                    ? Builder.getFalse()
                                    : CI->getArgOperand(2);
+    Value *Dynamic =
+        CI->getNumArgOperands() < 3 ? Builder.getFalse() : CI->getArgOperand(3);
     NewCall = Builder.CreateCall(
-        NewFn, {CI->getArgOperand(0), CI->getArgOperand(1), NullIsUnknownSize});
+        NewFn, {CI->getArgOperand(0), CI->getArgOperand(1), NullIsUnknownSize, Dynamic});
     break;
   }
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp b/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
index cce17d02bef..8bf2b13c654 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
@@ -918,7 +918,8 @@ bool AMDGPUPromoteAlloca::handleAlloca(AllocaInst &I, bool SufficientLDS) {
       );
 
       CallInst *NewCall = Builder.CreateCall(
-          ObjectSize, {Src, Intr->getOperand(1), Intr->getOperand(2)});
+          ObjectSize,
+          {Src, Intr->getOperand(1), Intr->getOperand(2), Intr->getOperand(3)});
       Intr->replaceAllUsesWith(NewCall);
       Intr->eraseFromParent();
       continue;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index ec4b7635ce3..a705d7ac75f 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1894,9 +1894,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
   switch (II->getIntrinsicID()) {
   default: break;
   case Intrinsic::objectsize:
-    if (ConstantInt *N =
-            lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
-      return replaceInstUsesWith(CI, N);
+    if (Value *V = lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
+      return replaceInstUsesWith(CI, V);
     return nullptr;
   case Intrinsic::bswap: {
     Value *IIOperand = II->getArgOperand(0);
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 9a2a3b2dc5d..b30b3eeadcc 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2295,8 +2295,8 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
 
       if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
         if (II->getIntrinsicID() == Intrinsic::objectsize) {
-          ConstantInt *Result = lowerObjectSizeCall(II, DL, &TLI,
-                                                    /*MustSucceed=*/true);
+          Value *Result =
+              lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/true);
           replaceInstUsesWith(*I, Result);
           eraseInstFromFunction(*I);
           Users[i] = nullptr; // Skip examining in the next loop.
diff --git a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
index 547c43c5ddd..4dc9b611c15 100644
--- a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
+++ b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
@@ -142,8 +142,9 @@ static void insertBoundsCheck(Value *Or, BuilderTy IRB, GetTrapBBT GetTrapBB) {
 static bool addBoundsChecking(Function &F, TargetLibraryInfo &TLI,
                               ScalarEvolution &SE) {
   const DataLayout &DL = F.getParent()->getDataLayout();
-  ObjectSizeOffsetEvaluator ObjSizeEval(DL, &TLI, F.getContext(),
-                                           /*RoundToAlign=*/true);
+  ObjectSizeOpts EvalOpts;
+  EvalOpts.RoundToAlign = true;
+  ObjectSizeOffsetEvaluator ObjSizeEval(DL, &TLI, F.getContext(), EvalOpts);
 
   // check HANDLE_MEMORY_INST in include/llvm/Instruction.def for memory
   // touching instructions