[llvm] [SEH] Ignore EH pad check for internal intrinsics (PR #79694)

[Phoebe Wang via llvm-commits]

https://github.com/phoebewang created https://github.com/llvm/llvm-project/pull/79694

Intrinsics like @llvm.seh.scope.begin and @llvm.seh.scope.end which do not throw do not need funclets in catchpads or cleanuppads.

Fixes #69428

Co-authored-by: Robert Cox <robert.cox at intel.com>

>From 48908fb6d5387082018fb1d8b2f0ddb65e2e2baa Mon Sep 17 00:00:00 2001
From: Phoebe Wang <phoebe.wang at intel.com>
Date: Sat, 27 Jan 2024 22:03:06 +0800
Subject: [PATCH] [SEH] Ignore EH pad check for internal intrinsics

Intrinsics like @llvm.seh.scope.begin and @llvm.seh.scope.end which do not throw do not need funclets in catchpads or cleanuppads.

Fixes #69428

Co-authored-by: Robert Cox <robert.cox at intel.com>
---
 llvm/lib/IR/Verifier.cpp      |  5 +++
 llvm/test/Verifier/pr69428.ll | 80 +++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 llvm/test/Verifier/pr69428.ll

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 91cf91fbc788bd9..0f1e9fa40c9b037 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -4280,6 +4280,11 @@ void Verifier::visitEHPadPredecessors(Instruction &I) {
     if (auto *II = dyn_cast<InvokeInst>(TI)) {
       Check(II->getUnwindDest() == BB && II->getNormalDest() != BB,
             "EH pad must be jumped to via an unwind edge", ToPad, II);
+      auto *CalledFn =
+          dyn_cast<Function>(II->getCalledOperand()->stripPointerCasts());
+      if (CalledFn && CalledFn->isIntrinsic() && II->doesNotThrow() &&
+          !IntrinsicInst::mayLowerToFunctionCall(CalledFn->getIntrinsicID()))
+        continue;
       if (auto Bundle = II->getOperandBundle(LLVMContext::OB_funclet))
         FromPad = Bundle->Inputs[0];
       else
diff --git a/llvm/test/Verifier/pr69428.ll b/llvm/test/Verifier/pr69428.ll
new file mode 100644
index 000000000000000..22d732076e3af7a
--- /dev/null
+++ b/llvm/test/Verifier/pr69428.ll
@@ -0,0 +1,80 @@
+; RUN: llvm-as -disable-output %s
+
+%struct._List_node_emplace_op2 = type { i8 }
+
+$"??1?$_List_node_emplace_op2 at H@@QEAA at XZ" = comdat any
+
+@"?_List@@3HA" = dso_local local_unnamed_addr global i32 0, align 4
+
+; Function Attrs: mustprogress noreturn
+define dso_local void @"?ExecutionEngineaddExecutableDependency@@YAXXZ"() local_unnamed_addr #0 personality ptr @__CxxFrameHandler3 {
+entry:
+  %agg.tmp.ensured.i = alloca %struct._List_node_emplace_op2, align 1
+  call void @llvm.lifetime.start.p0(i64 1, ptr nonnull %agg.tmp.ensured.i)
+  %0 = load i32, ptr @"?_List@@3HA", align 4
+  %call.i = call noundef ptr @"??0?$_List_node_emplace_op2 at H@@QEAA at H@Z"(ptr noundef nonnull align 1 dereferenceable(1) %agg.tmp.ensured.i, i32 noundef %0)
+  invoke void @llvm.seh.scope.begin()
+          to label %invoke.cont.i unwind label %ehcleanup.i
+
+invoke.cont.i:                                    ; preds = %entry
+  invoke void @llvm.seh.scope.end()
+          to label %invoke.cont2.i unwind label %ehcleanup.i
+
+invoke.cont2.i:                                   ; preds = %invoke.cont.i
+  call void @"??1?$_List_node_emplace_op2 at H@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %agg.tmp.ensured.i) #6
+  unreachable
+
+ehcleanup.i:                                      ; preds = %invoke.cont.i, %entry
+  %1 = cleanuppad within none []
+  invoke void @llvm.seh.scope.begin()
+          to label %invoke.cont.i.i unwind label %ehcleanup.i.i
+
+invoke.cont.i.i:                                  ; preds = %ehcleanup.i
+  invoke void @llvm.seh.scope.end()
+          to label %"??1?$_List_node_emplace_op2 at H@@QEAA at XZ.exit.i" unwind label %ehcleanup.i.i
+
+ehcleanup.i.i:                                    ; preds = %invoke.cont.i.i, %ehcleanup.i
+  %2 = cleanuppad within %1 []
+  call void @"??1_Alloc_construct_ptr@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %agg.tmp.ensured.i) #6 [ "funclet"(token %2) ]
+  cleanupret from %2 unwind to caller
+
+"??1?$_List_node_emplace_op2 at H@@QEAA at XZ.exit.i":  ; preds = %invoke.cont.i.i
+  call void @"??1_Alloc_construct_ptr@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %agg.tmp.ensured.i) #6 [ "funclet"(token %1) ]
+  cleanupret from %1 unwind to caller
+}
+
+declare dso_local noundef ptr @"??0?$_List_node_emplace_op2 at H@@QEAA at H@Z"(ptr noundef nonnull returned align 1 dereferenceable(1), i32 noundef) unnamed_addr #1
+
+declare dso_local i32 @__CxxFrameHandler3(...)
+
+; Function Attrs: nofree nosync nounwind memory(none)
+declare dso_local void @llvm.seh.scope.begin() #2
+
+; Function Attrs: nofree nosync nounwind memory(none)
+declare dso_local void @llvm.seh.scope.end() #2
+
+; Function Attrs: mustprogress nounwind
+define linkonce_odr dso_local void @"??1?$_List_node_emplace_op2 at H@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %this) unnamed_addr #3 comdat align 2 personality ptr @__CxxFrameHandler3 {
+entry:
+  invoke void @llvm.seh.scope.begin()
+          to label %invoke.cont unwind label %ehcleanup
+
+invoke.cont:                                      ; preds = %entry
+  invoke void @llvm.seh.scope.end()
+          to label %invoke.cont2 unwind label %ehcleanup
+
+invoke.cont2:                                     ; preds = %invoke.cont
+  tail call void @"??1_Alloc_construct_ptr@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %this) #6
+  ret void
+
+ehcleanup:                                        ; preds = %invoke.cont, %entry
+  %0 = cleanuppad within none []
+  call void @"??1_Alloc_construct_ptr@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1) %this) #6 [ "funclet"(token %0) ]
+  cleanupret from %0 unwind to caller
+}
+
+; Function Attrs: nounwind
+declare dso_local void @"??1_Alloc_construct_ptr@@QEAA at XZ"(ptr noundef nonnull align 1 dereferenceable(1)) unnamed_addr #4
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
+declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #5