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DWARF v5: emit DW_AT_addr_base if DW_AT_low_pc references .debug_addr 

The condition !AddrPool.empty() is tested before attachRangesOrLowHighPC(), which may add an entry to AddrPool. We emit DW_AT_low_pc (DW_FORM_addrx) but may incorrectly omit DW_AT_addr_base for LineTablesOnly. This can be easily reproduced:

clang -gdwarf-5 -gmlt -c a.cc

Fix this by moving !AddrPool.empty() below.

This was discovered while investigating an lld crash (fixed by D61889) on such object files: ld.lld --gdb-index a.o

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D61891

llvm-svn: 360678
This commit is contained in:
Fangrui Song 2019-05-14 14:37:26 +00:00
parent 22561972af
commit 2f6ef2fc92
4 changed files with 31 additions and 8 deletions
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14
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@ -901,13 +901,6 @@ void DwarfDebug::finalizeModuleInfo() {
// ranges for all subprogram DIEs for mach-o.
DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
// We don't keep track of which addresses are used in which CU so this
// is a bit pessimistic under LTO.
if (!AddrPool.isEmpty() &&
(getDwarfVersion() >= 5 ||
(SkCU && !empty(TheCU.getUnitDie().children()))))
U.addAddrTableBase();
if (unsigned NumRanges = TheCU.getRanges().size()) {
if (NumRanges > 1 && useRangesSection())
// A DW_AT_low_pc attribute may also be specified in combination with
@ -920,6 +913,13 @@ void DwarfDebug::finalizeModuleInfo() {
U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges());
}
// We don't keep track of which addresses are used in which CU so this
// is a bit pessimistic under LTO.
if (!AddrPool.isEmpty() &&
(getDwarfVersion() >= 5 ||
(SkCU && !empty(TheCU.getUnitDie().children()))))
U.addAddrTableBase();
if (getDwarfVersion() >= 5) {
if (U.hasRangeLists())
U.addRnglistsBase();

21
llvm/test/DebugInfo/Generic/line-table-addrx.ll Normal file
View File

@ -0,0 +1,21 @@
; RUN: %llc_dwarf -filetype=obj %s -o - | llvm-dwarfdump -v -debug-info - | FileCheck %s
;; In DWARF v5, emit DW_AT_addr_base as DW_AT_addr_base is used for DW_AT_low_pc.
; CHECK: DW_AT_low_pc [DW_FORM_addrx]
; CHECK: DW_AT_addr_base
define i64 @foo() !dbg !7 {
entry:
ret i64 0
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, emissionKind: LineTablesOnly, enums: !2, nameTableKind: None)
!1 = !DIFile(filename: "a.cc", directory: "/tmp")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 5}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!7 = distinct !DISubprogram(name: "a", scope: !1, file: !1, line: 22, type: !8, scopeLine: 22, unit: !0, retainedNodes: !2)
!8 = !DISubroutineType(types: !2)

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

@ -11,9 +11,9 @@
; DW5-CHECK-NEXT: DW_AT_str_offsets_base (0x00000008)
; DW5-CHECK-NEXT: DW_AT_stmt_list (0x00000000)
; DW5-CHECK-NEXT: DW_AT_comp_dir {{.*}}
; DW5-CHECK-NEXT: DW_AT_addr_base (0x00000008)
; DW5-CHECK-NEXT: DW_AT_low_pc (0x0000000000000000)
; DW5-CHECK-NEXT: DW_AT_high_pc (0x0000000000000007)
; DW5-CHECK-NEXT: DW_AT_addr_base (0x00000008)
; DW5-CHECK-NEXT: DW_AT_loclists_base (0x0000000c)
; DW5-CHECK-EMPTY:
; DW5-CHECK-NEXT: 0x00000027: DW_TAG_base_type

2
llvm/test/DebugInfo/X86/fission-ranges.ll
View File

@ -12,6 +12,8 @@
; CHECK-NEXT: DW_AT_GNU_dwo_name
; CHECK-NEXT: DW_AT_GNU_dwo_id
; CHECK-NEXT: DW_AT_GNU_ranges_base
; CHECK-NEXT: DW_AT_low_pc
; CHECK-NEXT: DW_AT_high_pc
; CHECK-NEXT: DW_AT_GNU_addr_base [DW_FORM_sec_offset] (0x00000000)
; CHECK: .debug_info.dwo contents: