[LLD] Report errors occurred while parsing debug info as warnings.

[avl]

Summary

Extracted from D74773. Currently, errors happened while parsing
debug info are reported as errors. DebugInfoDWARF library treats such
errors as "Recoverable errors". This patch makes debug info errors
to be reported as warnings, to support DebugInfoDWARF approach.

[MaskRay]

lld/ELF/SyntheticSections.cpp

2671

Downgrading an error to a warning is fine.

lld/test/ELF/gdb-index-parse-fail.s

5

Why the ? metacharacter?

[avl]

lld/test/ELF/gdb-index-parse-fail.s

5

To have one or zero "(.debug_info):". Please check that description https://reviews.llvm.org/D74773#inline-683778

[jhenderson]

lld/test/ELF/gdb-index-invalid-ranges.s

8–10

Same comments as in the other test - why has the text changed in this patch when all you've done is change the severity of this error?

lld/test/ELF/gdb-index-parse-fail.s

5

But isn't in this patch this output unchanged from before? The only change in the text should be error -> warning.

[avl]

lld/test/ELF/gdb-index-invalid-ranges.s

8–10

right. this change should be done in D74773

[avl]

addressed comments: removed change related to D74773.

[jhenderson]

LGTM.

[MaskRay]

Some DWARF producer bugs (e.g. D75375) will change from an error to a warning. I think it is fine.

// clang -c -gdwarf-5 a.s -o a.o
.section .init; ret
.text; ret

ld.lld --gdb-index a.o

[MaskRay]

You can strip some Phabricator metadata tags, BTW:

% which arcfilter
arcfilter () {
        git log -1 --pretty=%B | awk '/Reviewers:|Subscribers:/{p=1} /Reviewed By:|Differential Revision:/{p=0} !p && !/^Summary:/' | git commit --amend -F -
}

lld/ELF/SyntheticSections.cpp

 
 static std::vector<GdbIndexSection::AddressEntry>
 readAddressAreas(DWARFContext &dwarf, InputSection *sec) {
   std::vector<GdbIndexSection::AddressEntry> ret;
 
   uint32_t cuIdx = 0;
   for (std::unique_ptr<DWARFUnit> &cu : dwarf.compile_units()) {
     if (Error e = cu->tryExtractDIEsIfNeeded(false)) {
-      error(toString(sec) + ": " + toString(std::move(e)));
+      warn(toString(sec) + ": " + toString(std::move(e)));
       return {};
     }
     Expected<DWARFAddressRangesVector> ranges = cu->collectAddressRanges();
     if (!ranges) {
-      error(toString(sec) + ": " + toString(ranges.takeError()));
+      warn(toString(sec) + ": " + toString(ranges.takeError()));
       return {};
     }
 
     ArrayRef<InputSectionBase *> sections = sec->file->getSections();
     for (DWARFAddressRange &r : *ranges) {
       if (r.SectionIndex == -1ULL)
         continue;
       InputSectionBase *s = sections[r.SectionIndex];

lld/test/ELF/gdb-index-invalid-ranges.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
-# RUN: not ld.lld --gdb-index -e main %t.o -o /dev/null 2>&1 | FileCheck %s
+# RUN: ld.lld --gdb-index -e main %t.o -o /dev/null 2>&1 | FileCheck %s
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/gdb-index-invalid-ranges.obj.s -o %t2.o
 # RUN: llvm-ar rc %t.a %t.o
-# RUN: not ld.lld --gdb-index -e main %t2.o %t.a -o /dev/null 2>&1 | FileCheck --check-prefix=ARCHIVE %s
+# RUN: ld.lld --gdb-index -e main %t2.o %t.a -o /dev/null 2>&1 | FileCheck --check-prefix=ARCHIVE %s
 
-# CHECK: ld.lld: error: {{.*}}gdb-index-invalid-ranges.s.tmp.o:(.debug_info): decoding address ranges: invalid range list entry at offset 0x10
-# ARCHIVE: ld.lld: error: {{.*}}gdb-index-invalid-ranges.s.tmp.a(gdb-index-invalid-ranges.s.tmp.o):(.debug_info): decoding address ranges: invalid range list entry at offset 0x10
+# CHECK: ld.lld: warning: {{.*}}gdb-index-invalid-ranges.s.tmp.o:(.debug_info): decoding address ranges: invalid range list entry at offset 0x10
+# ARCHIVE: ld.lld: warning: {{.*}}gdb-index-invalid-ranges.s.tmp.a(gdb-index-invalid-ranges.s.tmp.o):(.debug_info): decoding address ranges: invalid range list entry at offset 0x10
 
 .section .text.foo1,"ax",@progbits
 .globl f1
 .Lfunc_begin0:
 f1:
  nop
 .Lfunc_end0:
 
 .section .debug_abbrev,"",@progbits

lld/test/ELF/gdb-index-parse-fail.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
-# RUN: not ld.lld --gdb-index %t1.o -o /dev/null 2>&1 | FileCheck %s
+# RUN: ld.lld --gdb-index %t1.o -o /dev/null 2>&1 | FileCheck %s
 
-# CHECK: error: {{.*}}:(.debug_info): invalid reference to or invalid content in .debug_str_offsets[.dwo]: insufficient space for 32 bit header prefix
+# CHECK: warning: {{.*}}:(.debug_info): invalid reference to or invalid content in .debug_str_offsets[.dwo]: insufficient space for 32 bit header prefix
 
 .section .debug_abbrev,"",@progbits
   .byte  1                           # Abbreviation Code
   .byte  17                          # DW_TAG_compile_unit
   .byte  0                           # DW_CHILDREN_no
   .byte  114                         # DW_AT_str_offsets_base
   .byte  23                          # DW_FORM_sec_offset
   .byte  0                           # EOM(1)