use getTerminatorOrNull for Windows EH with LLVM23 (#5121)

Author: gnavdev28

gen/ms-cxx-helper.cpp

@@ -36,10 +36,18 @@ void findSuccessors(std::vector<llvm::BasicBlock *> &blocks,
                     llvm::BasicBlock *bb, llvm::BasicBlock *ebb) {
   blocks.push_back(bb);
   if (bb != ebb) {
+#if LLVM_VERSION_MAJOR >= 23
+    assert(bb->getTerminatorOrNull());
+#else
     assert(bb->getTerminator());
+#endif
     for (size_t pos = 0; pos < blocks.size(); ++pos) {
       bb = blocks[pos];
+#if LLVM_VERSION_MAJOR >= 23
+      if (auto term = bb->getTerminatorOrNull()) {
+#else
       if (auto term = bb->getTerminator()) {
+#endif
         llvm::BasicBlock *unwindDest = getUnwindDest(term);
         unsigned cnt = term->getNumSuccessors();
         for (unsigned s = 0; s < cnt; s++) {
@@ -84,10 +92,16 @@ void cloneBlocks(const std::vector<llvm::BasicBlock *> &srcblocks,
                  llvm::Value *funclet) {
   llvm::ValueToValueMapTy VMap;
   // map the terminal branch to the new target
-  if (continueWith)
-    if (auto term = srcblocks.back()->getTerminator())
-      if (auto succ = term->getSuccessor(0))
-        VMap[succ] = continueWith;
+  if (continueWith) {
+#if LLVM_VERSION_MAJOR >= 23
+    auto term = srcblocks.back()->getTerminatorOrNull();
+#else
+    auto term = srcblocks.back()->getTerminator();
+#endif
+    if (term)  
+      if (auto succ = term->getSuccessor(0))  
+            VMap[succ] = continueWith;  
+  }
 
   for (auto bb : srcblocks) {
     llvm::Function *F = bb->getParent();

gen/passes/GarbageCollect2Stack.cpp

@@ -611,7 +611,11 @@ static bool mayBeUsedAfterRealloc(Instruction *Def, BasicBlock::iterator Alloc,
 
     // All instructions after the starting point in this block have been
     // accounted for. Look for successors to add to the work list.
+#if LLVM_VERSION_MAJOR >= 23
+    auto *Term = B->getTerminatorOrNull();
+#else
     auto *Term = B->getTerminator();
+#endif
     unsigned SuccCount = Term->getNumSuccessors();
     for (unsigned i = 0; i < SuccCount; i++) {
       BasicBlock *Succ = Term->getSuccessor(i);

gen/trycatchfinally.cpp

@@ -374,7 +374,11 @@ llvm::BasicBlock *CleanupScope::run(IRState &irs, llvm::BasicBlock *sourceBlock,
 
     // And convert the BranchInst to the existing branch target to a
     // SelectInst so we can append the other cases to it.
+#if LLVM_VERSION_MAJOR >= 23
+    endBlock()->getTerminatorOrNull()->eraseFromParent();
+#else
     endBlock()->getTerminator()->eraseFromParent();
+#endif
     llvm::Value *sel =
         new llvm::LoadInst(branchSelectorType, branchSelector, "", endBlock());
     llvm::SwitchInst::Create(
@@ -405,7 +409,11 @@ llvm::BasicBlock *CleanupScope::run(IRState &irs, llvm::BasicBlock *sourceBlock,
 
   // We don't know this branch target yet, so add it to the SwitchInst...
   llvm::ConstantInt *const selectorVal = DtoConstUint(exitTargets.size());
+#if LLVM_VERSION_MAJOR >= 23
+  llvm::cast<llvm::SwitchInst>(endBlock()->getTerminatorOrNull())
+#else
   llvm::cast<llvm::SwitchInst>(endBlock()->getTerminator())
+#endif 
       ->addCase(selectorVal, continueWith);
 
   // ... insert the store into the source block...
@@ -428,7 +436,11 @@ llvm::BasicBlock *CleanupScope::runCopying(IRState &irs,
   if (isCatchSwitchBlock(beginBlock()))
     return continueWith;
   if (exitTargets.empty()) {
+#if LLVM_VERSION_MAJOR >= 23
+    if (!endBlock()->getTerminatorOrNull())
+#else
     if (!endBlock()->getTerminator())
+#endif
       // Set up the unconditional branch at the end of the cleanup
       createBranch(continueWith, endBlock());
 
@@ -459,7 +471,11 @@ llvm::BasicBlock *CleanupScope::runCopying(IRState &irs,
     // change the continuation target if the initial branch was created
     // by another instance with unwinding
     if (continueWith)
+#if LLVM_VERSION_MAJOR >= 23
+      if (auto term = endBlock()->getTerminatorOrNull())
+#else
       if (auto term = endBlock()->getTerminator())
+#endif
         if (auto succ = term->getSuccessor(0))
           if (succ != continueWith)
             remapBlocksValue(blocks, succ, continueWith);