OpenMPOpt: Fix null dereference on missing declaration cache

[arsenm]

Summary

Found by llvm-reduce fuzzing.

[jdoerfert]

Thanks for the fix.

[arsenm]

2e7640e6dcb45845cebd96ca8a9c00110b675562

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

struct AAHeapToSharedFunction : public AAHeapToShared {
   void initialize(Attributor &A) override {
     if (DisableOpenMPOptDeglobalization) {
       indicatePessimisticFixpoint();
       return;
     }
 
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
     auto &RFI = OMPInfoCache.RFIs[OMPRTL___kmpc_alloc_shared];
+    if (!RFI.Declaration)
+      return;
 
     Attributor::SimplifictionCallbackTy SCB =
         [](const IRPosition &, const AbstractAttribute *,
            bool &) -> std::optional<Value *> { return nullptr; };
     for (User *U : RFI.Declaration->users())
       if (CallBase *CB = dyn_cast<CallBase>(U)) {
         MallocCalls.insert(CB);
         A.registerSimplificationCallback(IRPosition::callsite_returned(*CB),
ChangeStatus manifest(Attributor &A) override {
     }
 
     return Changed;
   }
 
   ChangeStatus updateImpl(Attributor &A) override {
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
     auto &RFI = OMPInfoCache.RFIs[OMPRTL___kmpc_alloc_shared];
+    if (!RFI.Declaration)
+      return ChangeStatus::UNCHANGED;
+
     Function *F = getAnchorScope();
 
     auto NumMallocCalls = MallocCalls.size();
 
     // Only consider malloc calls executed by a single thread with a constant.
     for (User *U : RFI.Declaration->users()) {
       const auto &ED = A.getAAFor<AAExecutionDomain>(
           *this, IRPosition::function(*F), DepClassTy::REQUIRED);

llvm/test/Transforms/OpenMP/heap-to-shared-missing-declarations.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature --check-attributes --check-globals
+; REQUIRES: amdgpu-registered-target
+; RUN: opt -mtriple=amdgcn-amd-amdhsa -S -passes=openmp-opt < %s | FileCheck %s
+
+define internal void @outlined0() {
+; CHECK: Function Attrs: nounwind
+; CHECK-LABEL: define {{[^@]+}}@outlined0
+; CHECK-SAME: () #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    call void @func() #[[ATTR0]]
+; CHECK-NEXT:    [[I:%.*]] = call i32 @__kmpc_get_hardware_num_threads_in_block() #[[ATTR0]]
+; CHECK-NEXT:    ret void
+;
+bb:
+  call void @func()
+  %i = call i32 @__kmpc_get_hardware_num_threads_in_block()
+  ret void
+}
+
+define internal void @func() {
+; CHECK: Function Attrs: nounwind
+; CHECK-LABEL: define {{[^@]+}}@func
+; CHECK-SAME: () #[[ATTR0]] {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[I:%.*]] = load ptr, ptr null, align 4294967296
+; CHECK-NEXT:    store i64 0, ptr [[I]], align 8
+; CHECK-NEXT:    ret void
+;
+bb:
+  %i = load ptr, ptr addrspacecast (ptr addrspace(5) null to ptr), align 4294967296
+  store i64 0, ptr %i, align 8
+  ret void
+}
+
+define internal void @outlined1() {
+; CHECK: Function Attrs: nounwind
+; CHECK-LABEL: define {{[^@]+}}@outlined1
+; CHECK-SAME: () #[[ATTR0]] {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[I:%.*]] = icmp sle i32 1, 0
+; CHECK-NEXT:    br i1 [[I]], label [[BB1:%.*]], label [[BB2:%.*]]
+; CHECK:       common.ret:
+; CHECK-NEXT:    ret void
+; CHECK:       bb1:
+; CHECK-NEXT:    call void @func() #[[ATTR0]]
+; CHECK-NEXT:    br label [[COMMON_RET:%.*]]
+; CHECK:       bb2:
+; CHECK-NEXT:    call void @__kmpc_free_shared(ptr null, i64 0) #[[ATTR0]]
+; CHECK-NEXT:    br label [[COMMON_RET]]
+;
+bb:
+  %i = icmp sle i32 1, 0
+  br i1 %i, label %bb1, label %bb2
+
+common.ret:                                       ; preds = %bb2, %bb1
+  ret void
+
+bb1:                                              ; preds = %bb
+  call void @func()
+  br label %common.ret
+
+bb2:                                              ; preds = %bb
+  call void @__kmpc_free_shared(ptr null, i64 0)
+  br label %common.ret
+}
+
+define void @user() {
+; CHECK-LABEL: define {{[^@]+}}@user() {
+; CHECK-NEXT:    call void @outlined0() #[[ATTR0]]
+; CHECK-NEXT:    call void @outlined1() #[[ATTR0]]
+; CHECK-NEXT:    ret void
+;
+  call void @outlined0()
+  call void @outlined1()
+  ret void
+}
+
+declare i32 @__kmpc_get_hardware_num_threads_in_block()
+declare void @__kmpc_free_shared(ptr, i64)
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 7, !"openmp", i32 50}
+!1 = !{i32 7, !"openmp-device", i32 50}
+;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+; CHECK: attributes #[[ATTR1:[0-9]+]] = { nosync nounwind }
+;.
+; CHECK: [[META0:![0-9]+]] = !{i32 7, !"openmp", i32 50}
+; CHECK: [[META1:![0-9]+]] = !{i32 7, !"openmp-device", i32 50}
+;.