[IMPALA-8196] IR UDFs should not allow importing symbols with hidden visibility

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: Impala 3.1.0
• Component/s: Backend
• Labels: udf
• Target Version: Product Backlog
• Epic Color: ghx-label-7
• Assignee: Unassigned
• Reporter: Tim Armstrong
• Created: 13/Feb/19 17:35
• Updated: 13/Feb/19 17:41

Description

Discovered while working on IMPALA-8187, as part of which i'll add a test showing the behaviour

If an IR module has some hidden symbols in it, e.g. like the following, then we can actually create a UDF that calls the hidden symbol. This is inconsistent with the shared object UDFs.

; Function Attrs: norecurse nounwind uwtable
define hidden { i8, i64 } @_Z16UnexportedSymbolPN10impala_udf15FunctionContextE(%"class.impala_udf::FunctionContext"* nocapture readnone) local_unnamed_addr #3 {
  %2 = alloca %"struct.impala_udf::BigIntVal", align 8
  call void @_ZN10impala_udf9BigIntValC2El(%"struct.impala_udf::BigIntVal"* nonnull %2, i64 5)
  %3 = getelementptr inbounds %"struct.impala_udf::BigIntVal", %"struct.impala_udf::BigIntVal"* %2, i64 0, i32 0, i32 0
  %4 = load i8, i8* %3, align 8
  %5 = insertvalue { i8, i64 } undef, i8 %4, 0
  %6 = getelementptr inbounds %"struct.impala_udf::BigIntVal", %"struct.impala_udf::BigIntVal"* %2, i64 0, i32 1
  %7 = load i64, i64* %6, align 8
  %8 = insertvalue { i8, i64 } %5, i64 %7, 1
  ret { i8, i64 } %8
}