1 files changed, 24 insertions, 6 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
index 750b2233e67a..9ccbee819c35 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
@@ -76,9 +76,13 @@ bool LowerGlobalDtors::runOnModule(Module &M) {
       !ETy->getTypeAtIndex(2U)->isPointerTy())
     return false; // Not (int, ptr, ptr).
 
-  // Collect the contents of @llvm.global_dtors, collated by priority and
-  // associated symbol.
-  std::map<uint16_t, MapVector<Constant *, std::vector<Constant *>>> DtorFuncs;
+  // Collect the contents of @llvm.global_dtors, ordered by priority. Within a
+  // priority, sequences of destructors with the same associated object are
+  // recorded so that we can register them as a group.
+  std::map<
+      uint16_t,
+      std::vector<std::pair<Constant *, std::vector<Constant *>>>
+  > DtorFuncs;
   for (Value *O : InitList->operands()) {
     auto *CS = dyn_cast<ConstantStruct>(O);
     if (!CS)
@@ -96,7 +100,14 @@ bool LowerGlobalDtors::runOnModule(Module &M) {
     Constant *Associated = CS->getOperand(2);
     Associated = cast<Constant>(Associated->stripPointerCasts());
 
-    DtorFuncs[PriorityValue][Associated].push_back(DtorFunc);
+    auto &AtThisPriority = DtorFuncs[PriorityValue];
+    if (AtThisPriority.empty() || AtThisPriority.back().first != Associated) {
+        std::vector<Constant *> NewList;
+        NewList.push_back(DtorFunc);
+        AtThisPriority.push_back(std::make_pair(Associated, NewList));
+    } else {
+        AtThisPriority.back().second.push_back(DtorFunc);
+    }
   }
   if (DtorFuncs.empty())
     return false;
@@ -131,14 +142,19 @@ bool LowerGlobalDtors::runOnModule(Module &M) {
   // first function with __cxa_atexit.
   for (auto &PriorityAndMore : DtorFuncs) {
     uint16_t Priority = PriorityAndMore.first;
-    for (auto &AssociatedAndMore : PriorityAndMore.second) {
+    uint64_t Id = 0;
+    auto &AtThisPriority = PriorityAndMore.second;
+    for (auto &AssociatedAndMore : AtThisPriority) {
       Constant *Associated = AssociatedAndMore.first;
+      auto ThisId = Id++;
 
       Function *CallDtors = Function::Create(
           AtExitFuncTy, Function::PrivateLinkage,
           "call_dtors" +
               (Priority != UINT16_MAX ? (Twine(".") + Twine(Priority))
                                       : Twine()) +
+              (AtThisPriority.size() > 1 ? Twine("$") + Twine(ThisId)
+                                         : Twine()) +
               (!Associated->isNullValue() ? (Twine(".") + Associated->getName())
                                           : Twine()),
           &M);
@@ -146,7 +162,7 @@ bool LowerGlobalDtors::runOnModule(Module &M) {
       FunctionType *VoidVoid = FunctionType::get(Type::getVoidTy(C),
                                                  /*isVarArg=*/false);
 
-      for (auto Dtor : AssociatedAndMore.second)
+      for (auto Dtor : reverse(AssociatedAndMore.second))
         CallInst::Create(VoidVoid, Dtor, "", BB);
       ReturnInst::Create(C, BB);
 
@@ -155,6 +171,8 @@ bool LowerGlobalDtors::runOnModule(Module &M) {
           "register_call_dtors" +
               (Priority != UINT16_MAX ? (Twine(".") + Twine(Priority))
                                       : Twine()) +
+              (AtThisPriority.size() > 1 ? Twine("$") + Twine(ThisId)
+                                         : Twine()) +
               (!Associated->isNullValue() ? (Twine(".") + Associated->getName())
                                           : Twine()),
           &M);