[DebugInfo/Verifier] Don't emit error for missing module in index

[JDevlieghere]

Summary

We don't expect module names to be present in the index. This patch adds DW_TAG_module to the blacklist.

[labath]

looks good. If we end up doing this too often, we can consider changing the blacklist to a whitelist.

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

unsigned DWARFVerifier::verifyNameIndexCompleteness(
   // We deviate from the specification here, which says:
   // "The name index must contain an entry for each debugging information entry
   // that defines a named subprogram, label, variable, type, or namespace,
   // subject to ..."
   // Instead whitelisting all TAGs representing a "type" or a "subprogram", to
   // make sure we catch any missing items, we instead blacklist all TAGs that we
   // know shouldn't be indexed.
   switch (Die.getTag()) {
-  // Compile unit has a name but it shouldn't be indexed.
+  // Compile units and modules have names but shouldn't be indexed.
   case DW_TAG_compile_unit:
+  case DW_TAG_module:
     return 0;
 
   // Function and template parameters are not globally visible, so we shouldn't
   // index them.
   case DW_TAG_formal_parameter:
   case DW_TAG_template_value_parameter:
   case DW_TAG_template_type_parameter:
   case DW_TAG_GNU_template_parameter_pack:

llvm/test/DebugInfo/X86/DIModule.ll

 ; ModuleID = '/Volumes/Data/apple-internal/llvm/tools/clang/test/Modules/debug-info-moduleimport.m'
-; RUN: llc %s -o %t -filetype=obj
+; RUN: llc %s -accel-tables=Dwarf -o %t -filetype=obj
 ; RUN: llvm-dwarfdump -debug-info %t | FileCheck %s
+; RUN: llvm-dwarfdump -verify %t
 ; CHECK: DW_TAG_module
 ; CHECK-NEXT: DW_AT_name {{.*}}"DebugModule"
 ; CHECK-NEXT: DW_AT_LLVM_config_macros {{.*}}"-DMODULES=0"
 ; CHECK-NEXT: DW_AT_LLVM_include_path {{.*}}"/llvm/tools/clang/test/Modules/Inputs"
 ; CHECK-NEXT: DW_AT_LLVM_isysroot {{.*}}"/"
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx"