[PATCH] D94784: [llvm][nvptx] add atomicity to counter in ISelLowering

[Theodore Popp via Phabricator via llvm-commits]

tpopp created this revision.
tpopp added reviewers: bkramer, tra.
Herald added subscribers: jfb, hiraditya, jholewinski.
tpopp requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

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


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94784

Files:
  llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
  llvm/lib/Target/NVPTX/NVPTXISelLowering.h


Index: llvm/lib/Target/NVPTX/NVPTXISelLowering.h
===================================================================
--- llvm/lib/Target/NVPTX/NVPTXISelLowering.h
+++ llvm/lib/Target/NVPTX/NVPTXISelLowering.h
@@ -491,7 +491,8 @@
 
   std::string getPrototype(const DataLayout &DL, Type *, const ArgListTy &,
                            const SmallVectorImpl<ISD::OutputArg> &,
-                           MaybeAlign retAlignment, const CallBase &CB) const;
+                           MaybeAlign retAlignment, const CallBase &CB,
+                           const unsigned &uniqueCallSite) const;
 
   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                       const SmallVectorImpl<ISD::OutputArg> &Outs,
Index: llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
===================================================================
--- llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -65,7 +65,7 @@
 
 using namespace llvm;
 
-static unsigned int uniqueCallSite = 0;
+static std::atomic<unsigned> globalUniqueCallSite = ATOMIC_VAR_INIT(0);
 
 static cl::opt<bool> sched4reg(
     "nvptx-sched4reg",
@@ -1243,7 +1243,7 @@
 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, const unsigned &uniqueCallSite) const {
   auto PtrVT = getPointerTy(DL);
 
   bool isABI = (STI.getSmVersion() >= 20);
@@ -1422,6 +1422,7 @@
   if (!isABI)
     return Chain;
 
+  unsigned uniqueCallSite = globalUniqueCallSite.fetch_add(1);
   SDValue tempChain = Chain;
   Chain = DAG.getCALLSEQ_START(Chain, uniqueCallSite, 0, dl);
   SDValue InFlag = Chain.getValue(1);
@@ -1678,7 +1679,8 @@
     // 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[] = {
@@ -1838,7 +1840,6 @@
                                                    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


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