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llvm-project/lld/test/ELF/gdb-index-ranges-discarded.s

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Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded This restores r361830 "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded" and dependent commits (r362218, r362497) which were reverted by r364321, with a fix of a --gdb-index issue. .rela.debug_ranges contains relocations of range list entries: // start address of a range list entry // old: 0; after r361830: 0 00000000000033a0 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + 0 // end address of a range list entry // old: 0xe; after r361830: 0 00000000000033a8 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + e If both start and end addresses of a range list entry resolve to 0, DWARFDebugRangeList::isEndOfListEntry() will return true, then the .debug_range decoding loop will terminate prematurely: while (true) { decode StartAddress decode EndAddress if (Entry.isEndOfListEntry()) // prematurely break; Entries.push_back(Entry); } In lld/ELF/SyntheticSections.cpp, readAddressAreas() will read incomplete address ranges and the resulting .gdb_index will be incomplete. For files that gdb hasn't loaded their debug info, gdb uses .gdb_index to map addresses to CUs. The absent entries make gdb fail to symbolize some addresses. To address this issue, we simply allow relocations to undefined symbols in DWARF.cpp:findAux() and let RelocationResolver resolve them. This patch should fix: [1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html [2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067 llvm-svn: 364391
2019-06-26 16:09:08 +08:00
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
# RUN: ld.lld --gdb-index -e main %t.o -o %t
# RUN: llvm-dwarfdump -gdb-index %t | FileCheck %s
# CHECK: .gdb_index contents:
# CHECK: Address area offset = 0x28, has 1 entries:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
# CHECK-NEXT: Low/High address = [0x201120, 0x201121) (Size: 0x1), CU id = 0
Reland D61583 [ELF] Error on relocations to STT_SECTION symbols if the sections were discarded This restores r361830 "[ELF] Error on relocations to STT_SECTION symbols if the sections were discarded" and dependent commits (r362218, r362497) which were reverted by r364321, with a fix of a --gdb-index issue. .rela.debug_ranges contains relocations of range list entries: // start address of a range list entry // old: 0; after r361830: 0 00000000000033a0 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + 0 // end address of a range list entry // old: 0xe; after r361830: 0 00000000000033a8 R_X86_64_64 .text._ZN2v88internal7Isolate7factoryEv + e If both start and end addresses of a range list entry resolve to 0, DWARFDebugRangeList::isEndOfListEntry() will return true, then the .debug_range decoding loop will terminate prematurely: while (true) { decode StartAddress decode EndAddress if (Entry.isEndOfListEntry()) // prematurely break; Entries.push_back(Entry); } In lld/ELF/SyntheticSections.cpp, readAddressAreas() will read incomplete address ranges and the resulting .gdb_index will be incomplete. For files that gdb hasn't loaded their debug info, gdb uses .gdb_index to map addresses to CUs. The absent entries make gdb fail to symbolize some addresses. To address this issue, we simply allow relocations to undefined symbols in DWARF.cpp:findAux() and let RelocationResolver resolve them. This patch should fix: [1] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190603/659848.html [2] https://bugs.chromium.org/p/chromium/issues/detail?id=978067 llvm-svn: 364391
2019-06-26 16:09:08 +08:00
## .debug_ranges contains 2 entries. .Lfunc_end0 is defined in the discarded
## .text.foo. Test we resolve it to a non-zero value, otherwise the address area
## of .gdb_index will not included [.Lfunc_begin1, .Lfunc_end1).
.section .text.foo,"aex",@progbits
.Lfunc_begin0:
ret
.Lfunc_end0:
.section .text.bar,"ax",@progbits
.Lfunc_begin1:
ret
.Lfunc_end1:
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.byte 85 # DW_AT_ranges
.byte 23 # DW_FORM_sec_offset
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0
.section .debug_info,"",@progbits
.Lcu_begin0:
.long .Lcu_end0 - .Lcu_begin0 - 4
.short 4 # DWARF version number
.long 0 # Offset Into Abbrev. Section
.byte 8 # Address Size
.Ldie0:
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.long 0 # DW_AT_ranges
.Lcu_end0:
.section .debug_ranges,"",@progbits
.quad .Lfunc_begin0
.quad .Lfunc_end0
.quad .Lfunc_begin1
.quad .Lfunc_end1
.quad 0
.quad 0