PNaCl: Check we don't crash in -replace-ptrs-with-ints with odd metadata operands.

test/Transforms/NaCl/replace-ptrs-with-ints.ll

 ; RUN: opt %s -replace-ptrs-with-ints -S | FileCheck %s
 
 target datalayout = "p:32:32:32"
 
 
 %struct = type { i32, i32 }
 
 declare %struct* @addr_taken_func(%struct*)
 
 @addr_of_func = global %struct* (%struct*)* @addr_taken_func
@@ skipping 398 matching lines @@
 ; This case is currently not converted.
 ; CHECK-NEXT: call void @llvm.dbg.declare(metadata !{null}, metadata !2, metadata !14)
 ; CHECK-NEXT: ret void
 
 ; For now, debugging info for values is lost.  replaceAllUsesWith()
 ; does not work for metadata references -- it converts them to nulls.
 ; This makes dbg.value too tricky to handle for now.
 define void @debug_value(i32 %val, i8* %ptr) {
   tail call void @llvm.dbg.value(metadata !{i32 %val}, i64 1, metadata !1, metadata !14)
   tail call void @llvm.dbg.value(metadata !{i8* %ptr}, i64 2, metadata !1, metadata !14)
+
+; check that we don't crash when encountering odd things:
+  tail call void @llvm.dbg.value(metadata !{i8* null}, i64 3, metadata !1, metadata !14)
+  tail call void @llvm.dbg.value(metadata !{i8* undef}, i64 4, metadata !1, metadata !14)
+  tail call void @llvm.dbg.value(metadata !{}, i64 5, metadata !1, metadata !14)
   ret void
 }
 ; CHECK: define void @debug_value(i32 %val, i32 %ptr) {
 ; CHECK-NEXT: call void @llvm.dbg.value(metadata !{null}, i64 1, metadata !1, metadata !14)
 ; CHECK-NEXT: call void @llvm.dbg.value(metadata !{null}, i64 2, metadata !1, metadata !14)
+; CHECK-NEXT: call void @llvm.dbg.value(metadata !15, i64 3, metadata !1, metadata !14)
+; CHECK-NEXT: call void @llvm.dbg.value(metadata !16, i64 4, metadata !1, metadata !14)
+; CHECK-NEXT: call void @llvm.dbg.value(metadata !2, i64 5, metadata !1, metadata !14)
 ; CHECK-NEXT: ret void
 
 
 declare void @llvm.lifetime.start(i64 %size, i8* %ptr)
 declare {}* @llvm.invariant.start(i64 %size, i8* %ptr)
 declare void @llvm.invariant.end({}* %start, i64 %size, i8* %ptr)
 
 ; GVN can introduce the following horrible corner case of a lifetime
 ; marker referencing a PHI node.  But we convert the phi to i32 type,
 ; and lifetime.start doesn't work on an inttoptr converting an i32 phi
@@ skipping 201 matching lines @@
 !9 = metadata !{metadata !10}
 !10 = metadata !{metadata !"0x101\00ptr\0016777217\000", metadata !4, metadata !5, metadata !8} ; [ DW_TAG_arg_variable ] [ptr] [line 1]
 !11 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
 !12 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
 !13 = metadata !{metadata !"clang version 3.6.0"}
 !14 = metadata !{metadata !"0x102"}               ; [ DW_TAG_expression ]
 !15 = metadata !{i32 1, i32 16, metadata !4, null}
 !16 = metadata !{i32 2, i32 1, metadata !4, null}
 
 ; CHECK: !4 = metadata !{{{.*}}nop{{.*}}, void (i32)* @nop, {{.*}}} ; [ DW_TAG_subprogram ] [line 1] [def] [nop]