Attributor: Fix crash on undef in !callees

[jdoerfert]

LG

[arsenm]

fdd9761dd1a971c9f4d6776b511ea54d7765bfeb

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

ChangeStatus updateImpl(Attributor &A) override {
     if (CB->isInlineAsm()) {
       setHasUnknownCallee(false, Change);
       return Change;
     }
 
     // Process callee metadata if available.
     if (auto *MD = getCtxI()->getMetadata(LLVMContext::MD_callees)) {
       for (auto &Op : MD->operands()) {
-        Function *Callee = mdconst::extract_or_null<Function>(Op);
+        Function *Callee = mdconst::dyn_extract_or_null<Function>(Op);
         if (Callee)
           addCalledFunction(Callee, Change);
       }
       return Change;
     }
 
     // The most simple case.
     ProcessCalledOperand(CB->getCalledOperand());

llvm/test/Transforms/Attributor/callgraph.ll

 ; CHECK-LABEL: @func7(
 ; CHECK-NEXT:    call void [[UNKNOWN:%.*]](), !callees !2
 ; CHECK-NEXT:    ret void
 ;
   call void %unknown(), !callees !2
   ret void
 }
 
+; Check there's no crash if something that isn't a function appears in !callees
+define void @undef_in_callees() {
+; CHECK-LABEL: @undef_in_callees(
+; CHECK-NEXT:  cond.end.i:
+; CHECK-NEXT:    call void undef(i8* undef, i32 undef, i8* undef), !callees !3
+; CHECK-NEXT:    ret void
+;
+cond.end.i:
+  call void undef(i8* undef, i32 undef, i8* undef), !callees !3
+  ret void
+}
+
 !0 = !{!1}
 !1 = !{i64 0, i1 false}
 !2 = !{void ()* @func3, void ()* @func4}
+!3 = distinct !{void (i8*, i32, i8*)* undef, void (i8*, i32, i8*)* null}
 
 ; UTC_ARGS: --disable
 
 ; DOT-DAG: Node[[FUNC1:0x[a-z0-9]+]] [shape=record,label="{func1}"];
 ; DOT-DAG: Node[[FUNC2:0x[a-z0-9]+]] [shape=record,label="{func2}"];
 ; DOT-DAG: Node[[FUNC3:0x[a-z0-9]+]] [shape=record,label="{func3}"];
 ; DOT-DAG: Node[[FUNC4:0x[a-z0-9]+]] [shape=record,label="{func4}"];
 ; DOT-DAG: Node[[FUNC5:0x[a-z0-9]+]] [shape=record,label="{func5}"];