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[DebugInfo] (Always) include the dwo name in the hash (#100375)

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Since ce0c205813c74b4225180ac8a6e40fd52ea88229, we are doing that if a
single (LTO) compilation contains more than one compile unit, but the
same thing can happen if the non-lto and single-cu lto compilations,
typically when the CU ends up (nearly) empty. In my case, this happened
when LTO emptied two compile units.

Note that the source file name is already a part of the hash, so this
can only happen when a single file is compiled and linked twice into the
same application (most likely with different preprocessor defintiions).
While not exactly common, this pattern is used by some C code to
implement "templates".

The 2017 patch already hinted at the possibility of doing this
unconditionally, and this patch implements that. While the DWARF spec
hints at the option of using the type signature hashing algorithm for
the DWO_id purposes, AFAICT it does not actually require it, so I
believe this change is still conforming.

The relevant section of the spec is in Section 3.1.2 "Skeleton
Compilation Unit Entries" (in non-normative text):

```
The means of determining a compilation unit ID does not need to be
similar or related to the means of determining a type unit signature.
However, it should be suitable for detecting file version skew or other
kinds of mismatched files and for looking up a full split unit in a
DWARF package file (see Section 7.3.5 on page 190).
```
This commit is contained in:
Pavel Labath 2024-08-05 16:38:08 +02:00 committed by GitHub
parent 9884fd33db
commit 0e4c7fabd3
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
15 changed files with 74 additions and 91 deletions
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19
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
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@ -1260,13 +1260,6 @@ void DwarfDebug::finalizeModuleInfo() {
finishEntityDefinitions();
// Include the DWO file name in the hash if there's more than one CU.
// This handles ThinLTO's situation where imported CUs may very easily be
// duplicate with the same CU partially imported into another ThinLTO unit.
StringRef DWOName;
if (CUMap.size() > 1)
DWOName = Asm->TM.Options.MCOptions.SplitDwarfFile;
bool HasEmittedSplitCU = false;
// Handle anything that needs to be done on a per-unit basis after
@ -1295,11 +1288,13 @@ void DwarfDebug::finalizeModuleInfo() {
? dwarf::DW_AT_dwo_name
: dwarf::DW_AT_GNU_dwo_name;
finishUnitAttributes(TheCU.getCUNode(), TheCU);
TheCU.addString(TheCU.getUnitDie(), attrDWOName,
Asm->TM.Options.MCOptions.SplitDwarfFile);
SkCU->addString(SkCU->getUnitDie(), attrDWOName,
Asm->TM.Options.MCOptions.SplitDwarfFile);
// Emit a unique identifier for this CU.
StringRef DWOName = Asm->TM.Options.MCOptions.SplitDwarfFile;
TheCU.addString(TheCU.getUnitDie(), attrDWOName, DWOName);
SkCU->addString(SkCU->getUnitDie(), attrDWOName, DWOName);
// Emit a unique identifier for this CU. Include the DWO file name in the
// hash to avoid the case where two (almost) empty compile units have the
// same contents. This can happen if link-time optimization removes nearly
// all (unused) code from a CU.
uint64_t ID =
DIEHash(Asm, &TheCU).computeCUSignature(DWOName, TheCU.getUnitDie());
if (getDwarfVersion() >= 5) {

17
llvm/test/CodeGen/X86/dwarf-headers.ll
View File

@ -12,11 +12,10 @@
; RUN: -filetype=obj -O0 -mtriple=x86_64-unknown-linux-gnu < %s \
; RUN: | llvm-dwarfdump -v - | FileCheck %s --check-prefix=SINGLE-5
; RUN: llc -split-dwarf-file=foo.dwo -split-dwarf-output=%t.dwo \
; RUN: llc -split-dwarf-file=foo.dwo \
; RUN: -dwarf-version=5 -generate-type-units \
; RUN: -filetype=obj -O0 -mtriple=x86_64-unknown-linux-gnu < %s \
; RUN: | llvm-dwarfdump -v - | FileCheck %s --check-prefix=O-5
; RUN: llvm-dwarfdump -v %t.dwo | FileCheck %s --check-prefix=DWO-5
; Looking for DWARF headers to be generated correctly.
; There are 8 variants with 5 formats: v4 CU, v4 TU, v5 normal/partial CU,
@ -74,15 +73,15 @@
;
; O-5: .debug_info contents:
; O-5: 0x00000000: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_skeleton, abbr_offset
; O-5-SAME: DWO_id = 0xccd7e58ef8bf4aa6
; O-5-SAME: DWO_id = [[HASH:0x[0-9a-f]*]]
; O-5: 0x00000014: DW_TAG_skeleton_unit
;
; DWO-5: .debug_info.dwo contents:
; DWO-5: 0x00000000: Type Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_type, abbr_offset
; DWO-5: 0x00000018: DW_TAG_type_unit
; DWO-5: 0x00000035: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_compile, abbr_offset
; DWO-5-SAME: DWO_id = 0xccd7e58ef8bf4aa6
; DWO-5: 0x00000049: DW_TAG_compile_unit
; O-5: .debug_info.dwo contents:
; O-5: 0x00000000: Type Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_type, abbr_offset
; O-5: 0x00000018: DW_TAG_type_unit
; O-5: 0x00000035: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_compile, abbr_offset
; O-5-SAME: DWO_id = [[HASH]]
; O-5: 0x00000049: DW_TAG_compile_unit
; ModuleID = 't.cpp'

4
llvm/test/DebugInfo/COFF/fission-cu.ll
View File

@ -62,7 +62,7 @@ source_filename = "test/DebugInfo/X86/fission-cu.ll"
; CHECK-NEXT: DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)
; CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x00000000] = "e:\\llvm-project\\tmp")
; CHECK-NEXT: DW_AT_GNU_dwo_name [DW_FORM_strp] ( .debug_str[0x00000014] = "baz.dwo")
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH:0x[0-9a-f]*]])
; Check that the rest of the compile units have information.
; CHECK: .debug_info.dwo contents:
@ -74,7 +74,7 @@ source_filename = "test/DebugInfo/X86/fission-cu.ll"
; CHECK-NOT: DW_AT_low_pc
; CHECK-NOT: DW_AT_stmt_list
; CHECK-NOT: DW_AT_comp_dir
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH]])
; CHECK: DW_TAG_variable
; CHECK: DW_AT_name [DW_FORM_GNU_str_index] (indexed (00000000) string = "a")
; CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x{{[0-9a-f]*}} => {[[TYPE:0x[0-9a-f]*]]}

2
llvm/test/DebugInfo/COFF/fission-sections.ll
View File

@ -51,7 +51,7 @@ source_filename = "test/DebugInfo/X86/fission-cu.ll"
; DWO-NEXT: [ 2](sec 2)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .debug_str_offsets.dwo
; DWO-NEXT: AUX scnlen 0x14 nreloc 0 nlnno 0 checksum 0x9392f0f0 assoc 2 comdat 0
; DWO-NEXT: [ 4](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .debug_info.dwo
; DWO-NEXT: AUX scnlen 0x29 nreloc 0 nlnno 0 checksum 0xc8e5b275 assoc 3 comdat 0
; DWO-NEXT: AUX scnlen 0x29 nreloc 0 nlnno 0 checksum 0x{{[0-9a-f]*}} assoc 3 comdat 0
; DWO-NEXT: [ 6](sec 4)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .debug_abbrev.dwo
; DWO-NEXT: AUX scnlen 0x33 nreloc 0 nlnno 0 checksum 0x8056e5e4 assoc 4 comdat 0
; DWO-EMPTY:

17
llvm/test/DebugInfo/WebAssembly/dwarf-headers.ll
View File

@ -12,11 +12,10 @@
; RUN: -filetype=obj -O0 -mtriple= < %s \
; RUN: | llvm-dwarfdump -v - | FileCheck %s --check-prefix=SINGLE-5
; RUN: llc -split-dwarf-file=foo.dwo -split-dwarf-output=%t.dwo \
; RUN: llc -split-dwarf-file=foo.dwo \
; RUN: -dwarf-version=5 -generate-type-units \
; RUN: -filetype=obj -O0 -mtriple= < %s \
; RUN: | llvm-dwarfdump -v - | FileCheck %s --check-prefix=O-5
; RUN: llvm-dwarfdump -v %t.dwo | FileCheck %s --check-prefix=DWO-5
; This test is derived from test/CodeGen/X86/dwarf-headers.ll
@ -76,15 +75,15 @@
;
; O-5: .debug_info contents:
; O-5: 0x00000000: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_skeleton, abbr_offset
; O-5-SAME: DWO_id = 0xccd7e58ef8bf4aa6
; O-5-SAME: DWO_id = [[HASH:0x[0-9a-f]*]]
; O-5: 0x00000014: DW_TAG_skeleton_unit
;
; DWO-5: .debug_info.dwo contents:
; DWO-5: 0x00000000: Type Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_type, abbr_offset
; DWO-5: 0x00000018: DW_TAG_type_unit
; DWO-5: 0x00000035: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_compile, abbr_offset
; DWO-5-SAME: DWO_id = 0xccd7e58ef8bf4aa6
; DWO-5: 0x00000049: DW_TAG_compile_unit
; O-5: .debug_info.dwo contents:
; O-5: 0x00000000: Type Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_type, abbr_offset
; O-5: 0x00000018: DW_TAG_type_unit
; O-5: 0x00000035: Compile Unit: {{.*}} version = 0x0005, unit_type = DW_UT_split_compile, abbr_offset
; O-5-SAME: DWO_id = [[HASH]]
; O-5: 0x00000049: DW_TAG_compile_unit
; ModuleID = 't.cpp'

4
llvm/test/DebugInfo/WebAssembly/fission-cu.ll
View File

@ -62,7 +62,7 @@ source_filename = "test/DebugInfo/WebAssembly/fission-cu.ll"
; CHECK-NEXT: DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)
; CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x00000000] = "/usr/local/google/home/echristo/tmp")
; CHECK-NEXT: DW_AT_GNU_dwo_name [DW_FORM_strp] ( .debug_str[0x00000024] = "baz.dwo")
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH:0x[0-9a-f]*]])
; Check that the rest of the compile units have information.
; CHECK: .debug_info.dwo contents:
@ -74,7 +74,7 @@ source_filename = "test/DebugInfo/WebAssembly/fission-cu.ll"
; CHECK-NOT: DW_AT_low_pc
; CHECK-NOT: DW_AT_stmt_list
; CHECK-NOT: DW_AT_comp_dir
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH]])
; CHECK: DW_TAG_variable
; CHECK: DW_AT_name [DW_FORM_GNU_str_index] (indexed (00000000) string = "a")
; CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x{{[0-9a-f]*}} => {[[TYPE:0x[0-9a-f]*]]}

4
llvm/test/DebugInfo/X86/convert-debugloc.ll
View File

@ -27,7 +27,9 @@
; RUN: | FileCheck %s --check-prefix=VERBOSE --check-prefix=CONV "--implicit-check-not={{DW_TAG|NULL}}"
; SPLITCONV: Compile Unit:{{.*}} DWO_id = 0x06580df9fdd5b54b
;; NB: This checks that the type reference in DW_OP_convert participates in the
;; DWO hash.
; SPLITCONV: Compile Unit:{{.*}} DWO_id = 0xbf4ac610d9ea282c
; SPLIT: DW_TAG_skeleton_unit
; CONV: DW_TAG_compile_unit

2
llvm/test/DebugInfo/X86/convert-loclist.ll
View File

@ -13,7 +13,7 @@
; often - add another IR file with a different DW_OP_convert that's otherwise
; identical and demonstrate that they have different DWO IDs.
; SPLIT: 0x00000000: Compile Unit: {{.*}} DWO_id = 0x4dbee91db55385db
; SPLIT: 0x00000000: Compile Unit: {{.*}} DWO_id = 0x6f8c6730fe6cbff0
; Regression testing a fairly quirky bug where instead of hashing (see above),
; extra bytes would be emitted into the output assembly in no

4
llvm/test/DebugInfo/X86/fission-cu.ll
View File

@ -60,7 +60,7 @@ source_filename = "test/DebugInfo/X86/fission-cu.ll"
; CHECK-NEXT: DW_AT_stmt_list [DW_FORM_sec_offset] (0x00000000)
; CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x00000000] = "/usr/local/google/home/echristo/tmp")
; CHECK-NEXT: DW_AT_GNU_dwo_name [DW_FORM_strp] ( .debug_str[0x00000024] = "baz.dwo")
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK-NEXT: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH:0x[0-9a-f]*]])
; Check that the rest of the compile units have information.
; CHECK: .debug_info.dwo contents:
@ -72,7 +72,7 @@ source_filename = "test/DebugInfo/X86/fission-cu.ll"
; CHECK-NOT: DW_AT_low_pc
; CHECK-NOT: DW_AT_stmt_list
; CHECK-NOT: DW_AT_comp_dir
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x1f1f859683d49324)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] ([[HASH]])
; CHECK: DW_TAG_variable
; CHECK: DW_AT_name [DW_FORM_GNU_str_index] (indexed (00000000) string = "a")
; CHECK: DW_AT_type [DW_FORM_ref4] (cu + 0x{{[0-9a-f]*}} => {[[TYPE:0x[0-9a-f]*]]}

4
llvm/test/DebugInfo/X86/fission-hash-local.ll
View File

@ -13,8 +13,8 @@
; int i = 7; // or 9
; }
; H1: DW_AT_GNU_dwo_id (0xc1220cf66b1190ad)
; H2: DW_AT_GNU_dwo_id (0xf66067a0cf366f0e)
; H1: DW_AT_GNU_dwo_id (0xb06b36aa6004befe)
; H2: DW_AT_GNU_dwo_id (0xc3e980cf3dfa79a2)
; Function Attrs: norecurse nounwind readnone uwtable
define dso_local void @_Z2f1v() local_unnamed_addr !dbg !7 {

4
llvm/test/DebugInfo/X86/fission-hash.ll
View File

@ -3,8 +3,8 @@
; The source is an empty file, modified to include/retain an 'int' type, since empty CUs are omitted.
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x50d985146a74bb00)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0x50d985146a74bb00)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0xb1b50e9a23896bc1)
; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8] (0xb1b50e9a23896bc1)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}

33
llvm/test/DebugInfo/X86/split-dwarf-dwo-hash.ll Normal file
View File

@ -0,0 +1,33 @@
; RUN: rm -rf %t && mkdir -p %t
; RUN: llc -split-dwarf-file=foo.dwo %s -filetype=obj -o %t/a.o
; RUN: llc -split-dwarf-file=bar.dwo %s -filetype=obj -o %t/b.o
; RUN: llvm-dwarfdump -debug-info %t/a.o %t/b.o | FileCheck %s
; CHECK: {{.*}}a.o: file format elf64-x86-64
; CHECK: 0x00000000: Compile Unit: {{.*}}, DWO_id = [[HASH:0x[0-9a-f]*]]
; CHECK: {{.*}}b.o: file format elf64-x86-64
; CHECK-NOT: DWO_id = [[HASH]]
target triple = "x86_64-pc-linux"
; Function Attrs: noinline nounwind uwtable
define void @_Z1av() !dbg !9 {
entry:
ret void, !dbg !12
}
!llvm.dbg.cu = !{!0}
!llvm.ident = !{!5}
!llvm.module.flags = !{!6, !7, !8}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "a.cpp", directory: "/tmp")
!2 = !{}
!5 = !{!"clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)"}
!6 = !{i32 2, !"Dwarf Version", i32 5}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{i32 1, !"wchar_size", i32 4}
!9 = distinct !DISubprogram(name: "a", linkageName: "_Z1av", scope: !1, file: !1, line: 1, type: !10, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
!10 = !DISubroutineType(types: !11)
!11 = !{null}
!12 = !DILocation(line: 2, column: 1, scope: !9)

45
llvm/test/DebugInfo/X86/split-dwarf-multiple-cu-hash.ll
View File

@ -1,45 +0,0 @@
; RUN: rm -rf %t && mkdir -p %t
; RUN: llc -split-dwarf-file=foo.dwo %s -filetype=obj -o %t/a.o
; RUN: llc -split-dwarf-file=bar.dwo %s -filetype=obj -o %t/b.o
; RUN: llvm-dwarfdump -debug-info %t/a.o %t/b.o | FileCheck %s
; CHECK: .debug_info contents:
; CHECK: dwo_id {{.*}}([[HASH:.*]])
; CHECK-NOT: dwo_id {{.*}}([[HASH]])
; CHECK: .debug_info.dwo contents:
target triple = "x86_64-pc-linux"
; Function Attrs: noinline nounwind uwtable
define void @_Z1av() #0 !dbg !9 {
entry:
ret void, !dbg !12
}
; Function Attrs: noinline nounwind uwtable
define void @_Z1bv() #0 !dbg !13 {
entry:
ret void, !dbg !14
}
attributes #0 = { noinline nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.dbg.cu = !{!0, !3}
!llvm.ident = !{!5, !5}
!llvm.module.flags = !{!6, !7, !8}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "a.cpp", directory: "/usr/local/google/home/blaikie/dev/scratch")
!2 = !{}
!3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !4, producer: "clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!4 = !DIFile(filename: "b.cpp", directory: "/usr/local/google/home/blaikie/dev/scratch")
!5 = !{!"clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)"}
!6 = !{i32 2, !"Dwarf Version", i32 4}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{i32 1, !"wchar_size", i32 4}
!9 = distinct !DISubprogram(name: "a", linkageName: "_Z1av", scope: !1, file: !1, line: 1, type: !10, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
!10 = !DISubroutineType(types: !11)
!11 = !{null}
!12 = !DILocation(line: 2, column: 1, scope: !9)
!13 = distinct !DISubprogram(name: "b", linkageName: "_Z1bv", scope: !4, file: !4, line: 1, type: !10, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !3, retainedNodes: !2)
!14 = !DILocation(line: 2, column: 1, scope: !13)

4
llvm/test/DebugInfo/X86/sret.ll
View File

@ -5,8 +5,8 @@
; Based on the debuginfo-tests/sret.cpp code.
; CHECK-DWO: DW_AT_GNU_dwo_id (0x7db1cc8453a47c44)
; CHECK-DWO: DW_AT_GNU_dwo_id (0x7db1cc8453a47c44)
; CHECK-DWO: DW_AT_GNU_dwo_id (0x044dcdf3d75b11a1)
; CHECK-DWO: DW_AT_GNU_dwo_id (0x044dcdf3d75b11a1)
; RUN: llc -O0 -fast-isel=true -mtriple=x86_64-apple-darwin -filetype=obj -o - %s | llvm-dwarfdump -debug-info - | FileCheck -check-prefixes=CHECK,FASTISEL %s
; RUN: llc -O0 -fast-isel=false -mtriple=x86_64-apple-darwin -filetype=obj -o - %s | llvm-dwarfdump -debug-info - | FileCheck -check-prefixes=CHECK,SDAG %s

2
llvm/test/MC/WebAssembly/dwarfdump.ll
View File

@ -66,7 +66,7 @@
; SPLIT-NEXT: DW_AT_language (DW_LANG_C99)
; SPLIT-NEXT: DW_AT_name ("test.c")
; SPLIT-NEXT: DW_AT_GNU_dwo_name ("{{.*}}dwarfdump.ll.tmp.dwo")
; SPLIT-NEXT: DW_AT_GNU_dwo_id (0xad3151f12153fa17)
; SPLIT-NEXT: DW_AT_GNU_dwo_id ({{.*}})
; SPLIT: 0x00000019: DW_TAG_variable
; SPLIT-NEXT: DW_AT_name ("foo")