[BOLT][DWARF] Fix handling of loclists_base without location accesses

There are CUs that have DW_AT_loclists_base, but no DW_AT_location in children
DIEs. Pre-bolt it points to a valid offset. We were not updating it, so it ended
up pointing in the middle of a list and caused LLDB to print out errors. Changed
it to point to first location list. I don't think it should matter since there
are no accesses to it anyway.

Reviewed By: maksfb

Differential Revision: https://reviews.llvm.org/D149798

3 files changed, 476 insertions, 1 deletions

diff --git a/bolt/lib/Core/DebugData.cpp b/bolt/lib/Core/DebugData.cpp
index 2b56357df9c0..f1204925a98a 100644
--- a/bolt/lib/Core/DebugData.cpp
+++ b/bolt/lib/Core/DebugData.cpp
@@ -732,8 +732,16 @@ void DebugLoclistWriter::addList(AttrInfo &AttrVal,
 uint32_t DebugLoclistWriter::LoclistBaseOffset = 0;
 void DebugLoclistWriter::finalizeDWARF5(
     DebugInfoBinaryPatcher &DebugInfoPatcher, DebugAbbrevWriter &AbbrevWriter) {
-  if (LocBodyBuffer->empty())
+  if (LocBodyBuffer->empty()) {
+    std::optional<AttrInfo> AttrInfoVal =
+        findAttributeInfo(CU.getUnitDIE(), dwarf::DW_AT_loclists_base);
+    // Pointing to first one, because it doesn't matter. There are no uses of it
+    // in this CU.
+    if (!isSplitDwarf() && AttrInfoVal)
+      DebugInfoPatcher.addLE32Patch(AttrInfoVal->Offset,
+                                    getDWARF5RngListLocListHeaderSize());
     return;
+  }
 
   std::unique_ptr<DebugBufferVector> LocArrayBuffer =
       std::make_unique<DebugBufferVector>();
diff --git a/bolt/test/X86/Inputs/dwarf5-loc-base-no-loc-accesshelper.s b/bolt/test/X86/Inputs/dwarf5-loc-base-no-loc-accesshelper.s
new file mode 100644
index 000000000000..dcf9f6a23a07
--- /dev/null
+++ b/bolt/test/X86/Inputs/dwarf5-loc-base-no-loc-accesshelper.s
@@ -0,0 +1,410 @@
+# clang++ helper.cpp -g -O2 -S
+# int fooVar = 0;
+# void useFoo(int * x) {
+# *x += 4;
+# }
+#
+# int  foo(int argc) {
+#    int x = argc;
+#    useFoo(&x);
+#    return x;
+# }
+# Manually removed DW_AT_location
+	.text
+	.file	"foo.cpp"
+	.file	0 "/testLocListMultiple" "foo.cpp" md5 0x9410f31145d031fcc1f2464b809e409a
+	.globl	_Z6useFooPi                     # -- Begin function _Z6useFooPi
+	.p2align	4, 0x90
+	.type	_Z6useFooPi,@function
+_Z6useFooPi:                            # @_Z6useFooPi
+.Lfunc_begin0:
+	.loc	0 2 0                           # foo.cpp:2:0
+	.cfi_startproc
+# %bb.0:                                # %entry
+	#DEBUG_VALUE: useFoo:x <- $rdi
+	.loc	0 3 4 prologue_end              # foo.cpp:3:4
+	addl	$4, (%rdi)
+	.loc	0 4 1                           # foo.cpp:4:1
+	retq
+.Ltmp0:
+.Lfunc_end0:
+	.size	_Z6useFooPi, .Lfunc_end0-_Z6useFooPi
+	.cfi_endproc
+                                        # -- End function
+	.globl	_Z3fooi                         # -- Begin function _Z3fooi
+	.p2align	4, 0x90
+	.type	_Z3fooi,@function
+_Z3fooi:                                # @_Z3fooi
+.Lfunc_begin1:
+	.loc	0 6 0                           # foo.cpp:6:0
+	.cfi_startproc
+# %bb.0:                                # %entry
+	#DEBUG_VALUE: foo:argc <- $edi
+	#DEBUG_VALUE: foo:x <- $edi
+                                        # kill: def $edi killed $edi def $rdi
+	#DEBUG_VALUE: useFoo:x <- undef
+	.loc	0 3 4 prologue_end              # foo.cpp:3:4
+	leal	4(%rdi), %eax
+.Ltmp1:
+	#DEBUG_VALUE: foo:x <- $eax
+	.loc	0 9 4                           # foo.cpp:9:4
+	retq
+.Ltmp2:
+.Lfunc_end1:
+	.size	_Z3fooi, .Lfunc_end1-_Z3fooi
+	.cfi_endproc
+                                        # -- End function
+	.type	fooVar,@object                  # @fooVar
+	.bss
+	.globl	fooVar
+	.p2align	2
+fooVar:
+	.long	0                               # 0x0
+	.size	fooVar, 4
+
+	.section	.debug_loclists,"",@progbits
+	.long	.Ldebug_list_header_end0-.Ldebug_list_header_start0 # Length
+.Ldebug_list_header_start0:
+	.short	5                               # Version
+	.byte	8                               # Address size
+	.byte	0                               # Segment selector size
+	.long	1                               # Offset entry count
+.Lloclists_table_base0:
+	.long	.Ldebug_loc0-.Lloclists_table_base0
+.Ldebug_loc0:
+	.byte	4                               # DW_LLE_offset_pair
+	.uleb128 .Lfunc_begin1-.Lfunc_begin0    #   starting offset
+	.uleb128 .Ltmp1-.Lfunc_begin0           #   ending offset
+	.byte	1                               # Loc expr size
+	.byte	85                              # super-register DW_OP_reg5
+	.byte	4                               # DW_LLE_offset_pair
+	.uleb128 .Ltmp1-.Lfunc_begin0           #   starting offset
+	.uleb128 .Lfunc_end1-.Lfunc_begin0      #   ending offset
+	.byte	1                               # Loc expr size
+	.byte	80                              # super-register DW_OP_reg0
+	.byte	0                               # DW_LLE_end_of_list
+.Ldebug_list_header_end0:
+	.section	.debug_abbrev,"",@progbits
+	.byte	1                               # Abbreviation Code
+	.byte	17                              # DW_TAG_compile_unit
+	.byte	1                               # DW_CHILDREN_yes
+	.byte	37                              # DW_AT_producer
+	.byte	37                              # DW_FORM_strx1
+	.byte	19                              # DW_AT_language
+	.byte	5                               # DW_FORM_data2
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	114                             # DW_AT_str_offsets_base
+	.byte	23                              # DW_FORM_sec_offset
+	.byte	16                              # DW_AT_stmt_list
+	.byte	23                              # DW_FORM_sec_offset
+	.byte	27                              # DW_AT_comp_dir
+	.byte	37                              # DW_FORM_strx1
+	.byte	17                              # DW_AT_low_pc
+	.byte	27                              # DW_FORM_addrx
+	.byte	18                              # DW_AT_high_pc
+	.byte	6                               # DW_FORM_data4
+	.byte	115                             # DW_AT_addr_base
+	.byte	23                              # DW_FORM_sec_offset
+	.ascii	"\214\001"                      # DW_AT_loclists_base
+	.byte	23                              # DW_FORM_sec_offset
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	2                               # Abbreviation Code
+	.byte	52                              # DW_TAG_variable
+	.byte	0                               # DW_CHILDREN_no
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	63                              # DW_AT_external
+	.byte	25                              # DW_FORM_flag_present
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	3                               # Abbreviation Code
+	.byte	36                              # DW_TAG_base_type
+	.byte	0                               # DW_CHILDREN_no
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	62                              # DW_AT_encoding
+	.byte	11                              # DW_FORM_data1
+	.byte	11                              # DW_AT_byte_size
+	.byte	11                              # DW_FORM_data1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	4                               # Abbreviation Code
+	.byte	46                              # DW_TAG_subprogram
+	.byte	1                               # DW_CHILDREN_yes
+	.byte	17                              # DW_AT_low_pc
+	.byte	27                              # DW_FORM_addrx
+	.byte	18                              # DW_AT_high_pc
+	.byte	6                               # DW_FORM_data4
+	.byte	64                              # DW_AT_frame_base
+	.byte	24                              # DW_FORM_exprloc
+	.byte	122                             # DW_AT_call_all_calls
+	.byte	25                              # DW_FORM_flag_present
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	5                               # Abbreviation Code
+	.byte	5                               # DW_TAG_formal_parameter
+	.byte	0                               # DW_CHILDREN_no
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	6                               # Abbreviation Code
+	.byte	46                              # DW_TAG_subprogram
+	.byte	1                               # DW_CHILDREN_yes
+	.byte	110                             # DW_AT_linkage_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	63                              # DW_AT_external
+	.byte	25                              # DW_FORM_flag_present
+	.byte	32                              # DW_AT_inline
+	.byte	33                              # DW_FORM_implicit_const
+	.byte	1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	7                               # Abbreviation Code
+	.byte	5                               # DW_TAG_formal_parameter
+	.byte	0                               # DW_CHILDREN_no
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	8                               # Abbreviation Code
+	.byte	15                              # DW_TAG_pointer_type
+	.byte	0                               # DW_CHILDREN_no
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	9                               # Abbreviation Code
+	.byte	46                              # DW_TAG_subprogram
+	.byte	1                               # DW_CHILDREN_yes
+	.byte	17                              # DW_AT_low_pc
+	.byte	27                              # DW_FORM_addrx
+	.byte	18                              # DW_AT_high_pc
+	.byte	6                               # DW_FORM_data4
+	.byte	64                              # DW_AT_frame_base
+	.byte	24                              # DW_FORM_exprloc
+	.byte	122                             # DW_AT_call_all_calls
+	.byte	25                              # DW_FORM_flag_present
+	.byte	110                             # DW_AT_linkage_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	63                              # DW_AT_external
+	.byte	25                              # DW_FORM_flag_present
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	10                              # Abbreviation Code
+	.byte	5                               # DW_TAG_formal_parameter
+	.byte	0                               # DW_CHILDREN_no
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	11                              # Abbreviation Code
+	.byte	52                              # DW_TAG_variable
+	.byte	0                               # DW_CHILDREN_no
+	.byte	3                               # DW_AT_name
+	.byte	37                              # DW_FORM_strx1
+	.byte	58                              # DW_AT_decl_file
+	.byte	11                              # DW_FORM_data1
+	.byte	59                              # DW_AT_decl_line
+	.byte	11                              # DW_FORM_data1
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	12                              # Abbreviation Code
+	.byte	29                              # DW_TAG_inlined_subroutine
+	.byte	0                               # DW_CHILDREN_no
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	17                              # DW_AT_low_pc
+	.byte	27                              # DW_FORM_addrx
+	.byte	18                              # DW_AT_high_pc
+	.byte	6                               # DW_FORM_data4
+	.byte	88                              # DW_AT_call_file
+	.byte	11                              # DW_FORM_data1
+	.byte	89                              # DW_AT_call_line
+	.byte	11                              # DW_FORM_data1
+	.byte	87                              # DW_AT_call_column
+	.byte	11                              # DW_FORM_data1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	0                               # EOM(3)
+	.section	.debug_info,"",@progbits
+.Lcu_begin0:
+	.long	.Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+	.short	5                               # DWARF version number
+	.byte	1                               # DWARF Unit Type
+	.byte	8                               # Address Size (in bytes)
+	.long	.debug_abbrev                   # Offset Into Abbrev. Section
+	.byte	1                               # Abbrev [1] 0xc:0x83 DW_TAG_compile_unit
+	.byte	0                               # DW_AT_producer
+	.short	33                              # DW_AT_language
+	.byte	1                               # DW_AT_name
+	.long	.Lstr_offsets_base0             # DW_AT_str_offsets_base
+	.long	.Lline_table_start0             # DW_AT_stmt_list
+	.byte	2                               # DW_AT_comp_dir
+	.byte	1                               # DW_AT_low_pc
+	.long	.Lfunc_end1-.Lfunc_begin0       # DW_AT_high_pc
+	.long	.Laddr_table_base0              # DW_AT_addr_base
+	.long	.Lloclists_table_base0          # DW_AT_loclists_base
+	.byte	2                               # Abbrev [2] 0x27:0xb DW_TAG_variable
+	.byte	3                               # DW_AT_name
+	.long	50                              # DW_AT_type
+                                        # DW_AT_external
+	.byte	0                               # DW_AT_decl_file
+	.byte	1                               # DW_AT_decl_line
+	.byte	0
+	.byte	3                               # Abbrev [3] 0x32:0x4 DW_TAG_base_type
+	.byte	4                               # DW_AT_name
+	.byte	5                               # DW_AT_encoding
+	.byte	4                               # DW_AT_byte_size
+	.byte	4                               # Abbrev [4] 0x36:0x14 DW_TAG_subprogram
+	.byte	1                               # DW_AT_low_pc
+	.long	.Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+	.byte	1                               # DW_AT_frame_base
+	.byte	87
+                                        # DW_AT_call_all_calls
+	.long	74                              # DW_AT_abstract_origin
+	.byte	5                               # Abbrev [5] 0x42:0x7 DW_TAG_formal_parameter
+	.long	79                              # DW_AT_abstract_origin
+	.byte	0                               # End Of Children Mark
+	.byte	6                               # Abbrev [6] 0x4a:0xe DW_TAG_subprogram
+	.byte	5                               # DW_AT_linkage_name
+	.byte	6                               # DW_AT_name
+	.byte	0                               # DW_AT_decl_file
+	.byte	2                               # DW_AT_decl_line
+                                        # DW_AT_external
+                                        # DW_AT_inline
+	.byte	7                               # Abbrev [7] 0x4f:0x8 DW_TAG_formal_parameter
+	.byte	7                               # DW_AT_name
+	.byte	0                               # DW_AT_decl_file
+	.byte	2                               # DW_AT_decl_line
+	.long	88                              # DW_AT_type
+	.byte	0                               # End Of Children Mark
+	.byte	8                               # Abbrev [8] 0x58:0x5 DW_TAG_pointer_type
+	.long	50                              # DW_AT_type
+	.byte	9                               # Abbrev [9] 0x5d:0x31 DW_TAG_subprogram
+	.byte	2                               # DW_AT_low_pc
+	.long	.Lfunc_end1-.Lfunc_begin1       # DW_AT_high_pc
+	.byte	1                               # DW_AT_frame_base
+	.byte	87
+                                        # DW_AT_call_all_calls
+	.byte	8                               # DW_AT_linkage_name
+	.byte	9                               # DW_AT_name
+	.byte	0                               # DW_AT_decl_file
+	.byte	6                               # DW_AT_decl_line
+	.long	50                              # DW_AT_type
+                                        # DW_AT_external
+	.byte	10                              # Abbrev [10] 0x6d:0xa DW_TAG_formal_parameter
+	.byte	10                              # DW_AT_name
+	.byte	0                               # DW_AT_decl_file
+	.byte	6                               # DW_AT_decl_line
+	.long	50                              # DW_AT_type
+	.byte	11                              # Abbrev [11] 0x77:0x9 DW_TAG_variable
+	.byte	7                               # DW_AT_name
+	.byte	0                               # DW_AT_decl_file
+	.byte	7                               # DW_AT_decl_line
+	.long	50                              # DW_AT_type
+	.byte	12                              # Abbrev [12] 0x80:0xd DW_TAG_inlined_subroutine
+	.long	74                              # DW_AT_abstract_origin
+	.byte	2                               # DW_AT_low_pc
+	.long	.Ltmp1-.Lfunc_begin1            # DW_AT_high_pc
+	.byte	0                               # DW_AT_call_file
+	.byte	8                               # DW_AT_call_line
+	.byte	4                               # DW_AT_call_column
+	.byte	0                               # End Of Children Mark
+	.byte	0                               # End Of Children Mark
+.Ldebug_info_end0:
+	.section	.debug_str_offsets,"",@progbits
+	.long	48                              # Length of String Offsets Set
+	.short	5
+	.short	0
+.Lstr_offsets_base0:
+	.section	.debug_str,"MS",@progbits,1
+.Linfo_string0:
+	.asciz	"clang version 15.0.0)" # string offset=0
+.Linfo_string1:
+	.asciz	"foo.cpp"                       # string offset=134
+.Linfo_string2:
+	.asciz	"/testLocListMultiple" # string offset=142
+.Linfo_string3:
+	.asciz	"fooVar"                        # string offset=199
+.Linfo_string4:
+	.asciz	"int"                           # string offset=206
+.Linfo_string5:
+	.asciz	"_Z6useFooPi"                   # string offset=210
+.Linfo_string6:
+	.asciz	"useFoo"                        # string offset=222
+.Linfo_string7:
+	.asciz	"x"                             # string offset=229
+.Linfo_string8:
+	.asciz	"_Z3fooi"                       # string offset=231
+.Linfo_string9:
+	.asciz	"foo"                           # string offset=239
+.Linfo_string10:
+	.asciz	"argc"                          # string offset=243
+	.section	.debug_str_offsets,"",@progbits
+	.long	.Linfo_string0
+	.long	.Linfo_string1
+	.long	.Linfo_string2
+	.long	.Linfo_string3
+	.long	.Linfo_string4
+	.long	.Linfo_string5
+	.long	.Linfo_string6
+	.long	.Linfo_string7
+	.long	.Linfo_string8
+	.long	.Linfo_string9
+	.long	.Linfo_string10
+	.section	.debug_addr,"",@progbits
+	.long	.Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+	.short	5                               # DWARF version number
+	.byte	8                               # Address size
+	.byte	0                               # Segment selector size
+.Laddr_table_base0:
+	.quad	fooVar
+	.quad	.Lfunc_begin0
+	.quad	.Lfunc_begin1
+.Ldebug_addr_end0:
+	.ident	"clang version 15.0.0"
+	.section	".note.GNU-stack","",@progbits
+	.addrsig
+	.section	.debug_line,"",@progbits
+.Lline_table_start0:
diff --git a/bolt/test/X86/dwarf5-one-loclists-two-bases.test b/bolt/test/X86/dwarf5-one-loclists-two-bases.test
new file mode 100644
index 000000000000..d85eca18b08a
--- /dev/null
+++ b/bolt/test/X86/dwarf5-one-loclists-two-bases.test
@@ -0,0 +1,57 @@
+# REQUIRES: system-linux
+
+# RUN: llvm-mc -dwarf-version=5 -filetype=obj -triple x86_64-unknown-linux %p/Inputs/dwarf5_main.s -o %tmain.o
+# RUN: llvm-mc -dwarf-version=5 -filetype=obj -triple x86_64-unknown-linux %p/Inputs/dwarf5-loc-base-no-loc-accesshelper.s -o %thelper.o
+# RUN: %clang %cflags -dwarf-5 %tmain.o %thelper.o -o %t.exe -Wl,-q
+# RUN: llvm-bolt %t.exe -o %t.bolt --update-debug-sections
+# RUN: llvm-dwarfdump --show-form --verbose --debug-info %t.exe | FileCheck --check-prefix=PRECHECK %s
+# RUN: llvm-dwarfdump --show-form --verbose --debug-addr %t.bolt > %t.txt
+# RUN: llvm-dwarfdump --show-form --verbose --debug-info %t.bolt >> %t.txt
+# RUN: cat %t.txt | FileCheck --check-prefix=POSTCHECK %s
+
+# This tests checks that re-writing of .debug_loclists is handled correctly when one of the CUs
+# doesn't have any DW_AT_location accesses.
+
+# PRECHECK: version = 0x0005
+# PRECHECK: DW_AT_loclists_base [DW_FORM_sec_offset] (0x0000000c)
+# PRECHECK-EMPTY:
+# PRECHECK: DW_TAG_variable
+# PRECHECK: DW_AT_location [DW_FORM_loclistx]
+# PRECHECK-SAME: indexed (0x0)
+# PRECHECK-SAME: loclist = 0x00000014
+# PRECHECK: DW_AT_location [DW_FORM_loclistx]
+# PRECHECK-SAME: indexed (0x1)
+# PRECHECK-SAME: loclist = 0x00000028
+# PRECHECK: DW_AT_loclists_base [DW_FORM_sec_offset]  (0x00000043)
+# PRECHECK-NOT: DW_AT_location
+
+# POSTCHECK: Addrs: [
+# POSTCHECK-NEXT: 0x
+# POSTCHECK-NEXT: 0x
+# POSTCHECK-NEXT: 0x[[#%.16x,ADDR:]]
+# POSTCHECK-NEXT: 0x[[#%.16x,ADDR2:]]
+
+# POSTCHECK: version = 0x0005
+# POSTCHECK: DW_AT_loclists_base [DW_FORM_sec_offset]	(0x0000000c)
+# POSTCHECK: DW_AT_rnglists_base [DW_FORM_sec_offset]	(0x0000000c)
+# POSTCHECK-EMPTY
+# POSTCHECK: DW_TAG_variable
+# POSTCHECK: DW_AT_location [DW_FORM_loclistx]
+# POSTCHECK-SAME: indexed (0x0)
+# POSTCHECK-SAME: loclist = 0x00000014
+# POSTCHECK-NEXT: [0x[[#ADDR]]
+# POSTCHECK-SAME: 0x[[#ADDR + 0x6]]
+# POSTCHECK-NEXT: [0x[[#ADDR + 0x6]]
+# POSTCHECK-SAME: 0x[[#ADDR + 0xc]]
+# POSTCHECK: DW_TAG_variable
+# POSTCHECK: DW_AT_location [DW_FORM_loclistx]
+# POSTCHECK-SAME: indexed (0x1)
+# POSTCHECK-SAME: loclist = 0x0000002a
+# POSTCHECK-NEXT: [0x[[#ADDR2]]
+# POSTCHECK-SAME: 0x[[#ADDR2 + 0x2]]
+
+# Checking second CU
+# POSTCHECK: version = 0x0005
+# POSTCHECK: DW_AT_loclists_base [DW_FORM_sec_offset]	(0x0000000c)
+# POSTCHECK: DW_AT_rnglists_base [DW_FORM_sec_offset]	(0x00000035)
+# POSTCHECK-NOT: DW_AT_location