[CodeGen][ARM64EC] Mangle EH personality handler names

llvm/lib/IR/EHPersonalities.cpp

@@ -25,7 +25,15 @@ EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
       Pers ? dyn_cast<GlobalValue>(Pers->stripPointerCasts()) : nullptr;
   if (!F || !F->getValueType() || !F->getValueType()->isFunctionTy())
     return EHPersonality::Unknown;
-  return StringSwitch<EHPersonality>(F->getName())
+
+  StringRef Name = F->getName();
+  if (Triple(F->getParent()->getTargetTriple()).isWindowsArm64EC()) {
+    // ARM64EC function symbols are mangled by prefixing them with "#".
+    // Demangle them by skipping this prefix.
+    Name.consume_front("#");
+  }
+
+  return StringSwitch<EHPersonality>(Name)
       .Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
       .Case("__gxx_personality_v0", EHPersonality::GNU_CXX)
       .Case("__gxx_personality_seh0", EHPersonality::GNU_CXX)

llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp

@@ -807,6 +807,17 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
   SetVector<GlobalAlias *> PatchableFns;
 
   for (Function &F : Mod) {
+    if (F.hasPersonalityFn()) {
+      GlobalValue *PersFn =
+          cast<GlobalValue>(F.getPersonalityFn()->stripPointerCasts());
+      if (PersFn->getValueType() && PersFn->getValueType()->isFunctionTy()) {
+        if (std::optional<std::string> MangledName =
+                getArm64ECMangledFunctionName(PersFn->getName().str())) {
+          PersFn->setName(MangledName.value());
+        }
+      }
+    }
+
     if (!F.hasFnAttribute(Attribute::HybridPatchable) || F.isDeclaration() ||
         F.hasLocalLinkage() || F.getName().ends_with("$hp_target"))
       continue;

llvm/test/CodeGen/AArch64/arm64ec-eh.ll

@@ -0,0 +1,65 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=arm64ec-pc-windows-msvc %s -o - | FileCheck %s
+
+define dso_local i32 @test() #0 personality ptr @__C_specific_handler {
+; CHECK-LABEL:  "#test"
+; CHECK:  .Lfunc_begin0:
+; CHECK-NEXT:  .seh_proc "#test"
+; CHECK-NEXT:    .seh_handler "#__C_specific_handler", @unwind, @except
+; CHECK-NEXT:  // %bb.0:
+; CHECK-NEXT:    sub sp, sp, #48
+; CHECK-NEXT:    .seh_stackalloc 48
+; CHECK-NEXT:    stp x29, x30, [sp, #16]             // 16-byte Folded Spill
+; CHECK-NEXT:    .seh_save_fplr 16
+; CHECK-NEXT:    add x29, sp, #16
+; CHECK-NEXT:    .seh_add_fp 16
+; CHECK-NEXT:    .seh_endprologue
+; CHECK-NEXT:    mov x0, #-2                         // =0xfffffffffffffffe
+; CHECK-NEXT:    mov w8, #-1                         // =0xffffffff
+; CHECK-NEXT:    stur x0, [x29, #16]
+; CHECK-NEXT:    stur w8, [x29, #-4]
+; CHECK-NEXT:  .Ltmp0:
+; CHECK-NEXT:    bl      "#ext"
+; CHECK-NEXT:  .Ltmp1:
+; CHECK-NEXT:  .LBB0_1:
+; CHECK-NEXT:  $ehgcr_0_1:
+; CHECK-NEXT:    stur    w0, [x29, #-4]
+; CHECK-NEXT:    .seh_startepilogue
+; CHECK-NEXT:    ldp     x29, x30, [sp, #16]             // 16-byte Folded Reload
+; CHECK-NEXT:    .seh_save_fplr  16
+; CHECK-NEXT:    add     sp, sp, #48
+; CHECK-NEXT:    .seh_stackalloc 48
+; CHECK-NEXT:    .seh_endepilogue
+; CHECK-NEXT:    ret
+; CHECK-NEXT:  .LBB0_2:
+; CHECK-NEXT:    mov     w0, wzr
+; CHECK-NEXT:    b       .LBB0_1
+  %1 = alloca i32, align 4
+  %2 = alloca i32, align 4
+  store i32 -1, ptr %1, align 4
+  %3 = invoke i32 @ext() #3
+          to label %12 unwind label %4
+
+4:                                                ; preds = %0
+  %5 = catchswitch within none [label %6] unwind to caller
+
+6:                                                ; preds = %4
+  %7 = catchpad within %5 [ptr null]
+  catchret from %7 to label %8
+
+8:                                                ; preds = %6
+  store i32 0, ptr %1, align 4
+  br label %10
+
+10:                                               ; preds = %8, %12
+  %11 = load i32, ptr %1, align 4
+  ret i32 %11
+
+12:                                               ; preds = %0
+  store i32 %3, ptr %1, align 4
+  br label %10
+}
+
+declare dso_local i32 @ext() #1
+
+declare dso_local i32 @__C_specific_handler(...)