[llvm][nvptx] add atomicity to counter in ISelLowering

Previously uniqueCallSite could have race conditions between different
threads. Now it is accessed with an atomic RMW and will be unique
between different threads.

Differential Revision: https://reviews.llvm.org/D94784

diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
index 05a0713..8860e90 100644 (file)
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -65,7 +65,7 @@
 
 using namespace llvm;
 
-static unsigned int uniqueCallSite = 0;
+static std::atomic<unsigned> GlobalUniqueCallSite;
 
 static cl::opt<bool> sched4reg(
     "nvptx-sched4reg",
@@ -1243,7 +1243,7 @@ NVPTXTargetLowering::LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const {
 std::string NVPTXTargetLowering::getPrototype(
     const DataLayout &DL, Type *retTy, const ArgListTy &Args,
     const SmallVectorImpl<ISD::OutputArg> &Outs, MaybeAlign retAlignment,
-    const CallBase &CB) const {
+    const CallBase &CB, unsigned UniqueCallSite) const {
   auto PtrVT = getPointerTy(DL);
 
   bool isABI = (STI.getSmVersion() >= 20);
@@ -1252,7 +1252,7 @@ std::string NVPTXTargetLowering::getPrototype(
     return "";
 
   std::stringstream O;
-  O << "prototype_" << uniqueCallSite << " : .callprototype ";
+  O << "prototype_" << UniqueCallSite << " : .callprototype ";
 
   if (retTy->getTypeID() == Type::VoidTyID) {
     O << "()";
@@ -1422,8 +1422,9 @@ SDValue NVPTXTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   if (!isABI)
     return Chain;
 
+  unsigned UniqueCallSite = GlobalUniqueCallSite.fetch_add(1);
   SDValue tempChain = Chain;
-  Chain = DAG.getCALLSEQ_START(Chain, uniqueCallSite, 0, dl);
+  Chain = DAG.getCALLSEQ_START(Chain, UniqueCallSite, 0, dl);
   SDValue InFlag = Chain.getValue(1);
 
   unsigned paramCount = 0;
@@ -1678,7 +1679,8 @@ SDValue NVPTXTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     // The prototype is embedded in a string and put as the operand for a
     // CallPrototype SDNode which will print out to the value of the string.
     SDVTList ProtoVTs = DAG.getVTList(MVT::Other, MVT::Glue);
-    std::string Proto = getPrototype(DL, RetTy, Args, Outs, retAlignment, *CB);
+    std::string Proto =
+        getPrototype(DL, RetTy, Args, Outs, retAlignment, *CB, UniqueCallSite);
     const char *ProtoStr =
       nvTM->getManagedStrPool()->getManagedString(Proto.c_str())->c_str();
     SDValue ProtoOps[] = {
@@ -1734,9 +1736,8 @@ SDValue NVPTXTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
 
   if (isIndirectCall) {
     SDVTList PrototypeVTs = DAG.getVTList(MVT::Other, MVT::Glue);
-    SDValue PrototypeOps[] = { Chain,
-                               DAG.getConstant(uniqueCallSite, dl, MVT::i32),
-                               InFlag };
+    SDValue PrototypeOps[] = {
+        Chain, DAG.getConstant(UniqueCallSite, dl, MVT::i32), InFlag};
     Chain = DAG.getNode(NVPTXISD::Prototype, dl, PrototypeVTs, PrototypeOps);
     InFlag = Chain.getValue(1);
   }
@@ -1832,13 +1833,10 @@ SDValue NVPTXTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     }
   }
 
-  Chain = DAG.getCALLSEQ_END(Chain,
-                             DAG.getIntPtrConstant(uniqueCallSite, dl, true),
-                             DAG.getIntPtrConstant(uniqueCallSite + 1, dl,
-                                                   true),
-                             InFlag, dl);
+  Chain = DAG.getCALLSEQ_END(
+      Chain, DAG.getIntPtrConstant(UniqueCallSite, dl, true),
+      DAG.getIntPtrConstant(UniqueCallSite + 1, dl, true), InFlag, dl);
   InFlag = Chain.getValue(1);
-  uniqueCallSite++;
 
   // Append ProxyReg instructions to the chain to make sure that `callseq_end`
   // will not get lost. Otherwise, during libcalls expansion, the nodes can become

diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.h b/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
index df9cd41..13829b9 100644 (file)
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.h
@@ -491,7 +491,8 @@ public:
 
   std::string getPrototype(const DataLayout &DL, Type *, const ArgListTy &,
                            const SmallVectorImpl<ISD::OutputArg> &,
-                           MaybeAlign retAlignment, const CallBase &CB) const;
+                           MaybeAlign retAlignment, const CallBase &CB,
+                           unsigned UniqueCallSite) const;
 
   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                       const SmallVectorImpl<ISD::OutputArg> &Outs,