Commit Graph

11 Commits

Author SHA1 Message Date
Georgii Rymar e4ceb8f421 [lib/ObjectYAML] - Make `ELFYAML::Relocation::Offset` optional.
Currently `yaml2obj` require `Offset` field in a relocation description.
There are many cases when `Offset` is insignificant in a context of a test case.

Making `Offset` optional allows to simplify our test cases.
This is what this patch does.

Also, with this patch `obj2yaml` does not dump a zero offset of a relocation.

Differential revision: https://reviews.llvm.org/D75608
2020-03-06 13:59:58 +03:00
Fangrui Song ba51fd5664 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 08:09:08 +00:00
Fangrui Song bd086817f6 [ELF] Initialize Target before it may be dereferenced by findAux when reporting "duplicate symbol" error
for (InputFile *F : Files)
      Symtab->addFile<ELFT>(F); // if there is a duplicate symbol error

    ...

    Target = getTarget();

When parsing .debug_info in the object file (for better diagnostics),
DWARF.cpp findAux may dereference the null pointer Target

    auto *DR = dyn_cast<Defined>(&File->getRelocTargetSym(Rel));
    if (!DR) {
      // Broken debug info may point to a non-defined symbol,
      // some asan object files may also contain R_X86_64_NONE
      RelType Type = Rel.getType(Config->IsMips64EL);
      if (Type != Target->NoneRel) /// Target is null

Move the assignment of Target to an earlier place to fix this.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D61712

llvm-svn: 360305
2019-05-09 01:45:53 +00:00
George Rimar ff3397247f [LLD] - Update the test cases after yaml2obj change.
https://reviews.llvm.org/D60122 (r357595) changed the
symbols description format.

This change updates the LLD tests.

llvm-svn: 357596
2019-04-03 14:54:22 +00:00
James Henderson 0cc32dd4a1 [ELF][test]Remove unnecessary empty symbol references in yaml/add missing symbols for relocs
yaml2obj used to require the Symbol field in relocations, but it hasn't
done so for a couple of years. Another change to yaml2obj will soon land
that will look up the symbol by name or index, if present, and emit an
error if not found. This will mean that an explicit symbol reference
(even to an empty-named symbol) that does not reference a symbol
declared in the yaml will result in an error.

This patch updates tests that would otherwise start emitting errors.

Reviewed by: ruiu, grimar

Differential Revision: https://reviews.llvm.org/D58508

llvm-svn: 354666
2019-02-22 11:22:39 +00:00
George Rimar 95aae4c59d [ELF] - Do not fail on R_*_NONE relocations when parsing the debug info.
This is https://bugs.llvm.org//show_bug.cgi?id=38919.

Currently, LLD may report "unsupported relocation target while parsing debug info"
when parsing the debug information.

At the same time LLD does that for zeroed R_X86_64_NONE relocations,
which obviously has "invalid" targets.

The nature of R_*_NONE relocation assumes them should be ignored.
This patch teaches LLD to stop reporting the debug information parsing errors for them.

Differential revision: https://reviews.llvm.org/D52408

llvm-svn: 343078
2018-09-26 08:11:34 +00:00
Fangrui Song 40a9f2251b [ELF] Replace unused output filenames with /dev/null in tests
Post commit review at rLLD335992

llvm-svn: 336129
2018-07-02 17:48:23 +00:00
Rafael Espindola 78fad32d83 Make the debug info in some tests more realistic.
Currently lld just parses the .debug_line section assuming that there
is only one compile unit. That assumption is false (PR36793).

I have a patch that changes lld to iterate over the compile units and
parse the portions of the .debug_line they point to (which fixes
PR36793).

A problem is that we will then need a compiler unit pointing to
.debug_line for lld to see it.

It seems like bfd has the same restriction.

This patch updates existing tests to add a minimal compile unit so
that they still work with PR36793 fixed.

llvm-svn: 328215
2018-03-22 17:14:41 +00:00
Rafael Espindola 8ce6db0c4b Error instead of ignoring broken debug info.
Thanks to Davide for noticing.

llvm-svn: 319401
2017-11-30 05:37:35 +00:00
Rafael Espindola e10568364e Fix reloc section alignment in test.
This should fix the ubsan bot.

We still have to fix lld to produce a clean error on unaligned reloc
sections.

llvm-svn: 319385
2017-11-29 23:39:12 +00:00
Rafael Espindola f893396d1b Don't crash on broken debug info.
llvm-svn: 319367
2017-11-29 22:09:16 +00:00