This patch enables yaml2elf emit the .debug_abbrev section.
The generated .debug_abbrev is verified using `llvm-dwarfdump`.
Known issues that will be addressed later:
- Current implementation doesn't support generating multiple abbreviation tables in one .debug_abbrev section.
Reviewed By: jhenderson, grimar
Differential Revision: https://reviews.llvm.org/D81820
We have an issue currently. The following YAML piece just ignores the `Excluded` key.
```
SectionHeaderTable:
Sections: []
Excluded:
- Name: .foo
```
Currently the meaning is: exclude the whole table.
The code checks that the `Sections` key is empty and doesn't catch/check
invalid/duplicated/missed `Excluded` entries.
Also there is no way to exclude all sections except the first null section,
because `Sections: []` currently just excludes the whole the sections header table.
To fix it, I suggest a change of the behavior.
1) A new `NoHeaders` key is added. It provides an explicit syntax to drop the whole table.
2) The meaning of the following is changed:
```
SectionHeaderTable:
Sections: []
Excluded:
- Name: .foo
```
Assuming there are 2 sections in the object (a null section and `.foo`), with this patch it
means: exclude the `.foo` section, keep the null section. The null section is an implicit
section and I think it is reasonable to make "Sections: []" to mean it is implicitly added.
It will be consistent with the global "Sections" tag that is used to describe sections.
3) `SectionHeaderTable->Sections` is now optional. No `Sections` is the same as
`Sections: []` (I think it avoids a confusion).
4) Using of `NoHeaders` together with `Sections`/`Excluded` is not allowed.
5) It is possible to use the `Excluded` key without the `Sections` key now (in this case
`Excluded` must contain all sections).
6) `SectionHeaderTable:` or `SectionHeaderTable: []` is not allowed.
7) When the `SectionHeaderTable` key is present, we still require all sections to be
present in `Sections` and `Excluded` lists. No changes here, we are still strict.
Differential revision: https://reviews.llvm.org/D81655
This teaches yaml2obj to allocate file space for a no-bits section
when there is a non-nobits section in the same segment that follows it.
It was discussed in D78005 thread and matches GNU linkers and LLD behavior.
Differential revision: https://reviews.llvm.org/D80629
Multiple times we faced an issue of huge outputs due to unexpected behavior
or incorrect test cases. The last one was https://reviews.llvm.org/D80629#2073066.
This patch limits the output to 10 Mb for ELF and introduces the --max-size to change this
limit.
I've tried to keep the implementation non-intrusive.
The current logic we have is that we prepare section content in a buffer first and write
it to the output later. This patch checks the available limit on each writing attempt to this buffer
and stops writing when the limit is reached and raises the internal error flag.
Later, this flag is is checked before the actual writing to a file happens and
an error is reported.
Differential revision: https://reviews.llvm.org/D81258
This patch enables yaml2elf emit the .debug_line section.
Test cases for emitting the dwarf64 .debug_line section and opcodes will be added later.
Known issues:
- We should replace `InitialLength` with `Format` and `Length`
- Currently implementation of the .debug_line section only fully supports DWARFv2, some header fields in DWARFv4 and DWARFv5 is missing, e.g., `header_length` in DWARFv4, `address_size` and `segment_selector_size` in DWARFv5.
- Some opcodes relies on the .debug_info section, we should warn user about it.
These issues will be addressed in a follow-up patch.
Reviewed By: jhenderson, grimar
Differential Revision: https://reviews.llvm.org/D81450
This patch intends to be an NFC-patch. Test cases will be added in a follow-up patch.
Reviewed By: jhenderson, grimar
Differential Revision: https://reviews.llvm.org/D81356
This implements a new "Excluded" key that can be used
to exclude entries from section header:
```
SectionHeaderTable:
Sections:
...
Excluded:
- Name: .foo
```
Differential revision: https://reviews.llvm.org/D81005
This patch enables yaml2obj to emit the .debug_aranges section in ELFYAML.
Known issues:
- The current implementation of `debug_aranges` doesn't support emitting `segment` in the `(segment, address, length)` tuple. I will fix it in a follow-up patch.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D80972
This teaches yaml2obj to allocate file space for a no-bits section
when there is a non-nobits section in the same segment that follows it.
It was discussed in D78005 thread and matches GNU linkers and LLD behavior.
Differential revision: https://reviews.llvm.org/D80629
With the "SectionHeaderTable" it is now possible to reorder
entries in the section header table.
It also allows to stop emitting the table.
Differential revision: https://reviews.llvm.org/D80002
Each `ELFYAML::ProgramHeader` currently contains a list of section names
included. We are trying to map them to Fill/Sections very late,
though we can create such mapping early, in `initProgramHeaders`.
The benefit is that with such change it is possible to access mapped
chunks earlier (for example during writing section content) and have
simpler code.
Differential revision: https://reviews.llvm.org/D80520
This change does not affect the produced binary.
In this patch I assign a technical suffix to each section/fill
(i.e. chunk) name when it is empty. It allows to simplify the code
slightly and improve error messages reported.
In the code we have the section to index mapping, SN2I, which is
globally used. With this change we can use it to map "empty"
names to indexes now, what is helpful.
Differential revision: https://reviews.llvm.org/D79984
For describing section/symbol names we can use unique suffixes,
e.g:
```
- Name: '.foo [1]`
- Name: '.foo [2]`
```
It can be a problem (see https://reviews.llvm.org/D79984#inline-734829),
because `[]` are sometimes used to describe a macros:
```
- Name: "[[a0]]"
```
Seems the better approach is to use something else, like "()".
This patch does it and refactors the code related.
Differential revision: https://reviews.llvm.org/D80123
Currently there is no good way to set a physical offset for a section:
* We have the `ShOffset` that allows to override the `sh_offset`, but
it does not affect the real data written.
* We can use a `Filler` to create an artificial gap, but it is more like a hack
rather than a proper solution for this problem.
This patch adds the `Offset` property which allows setting physical
offsets for sections.
It also generalizes the code, so that we set sh_offset field in one place
Differential revision: https://reviews.llvm.org/D78927
Currently we have computations of `p_filesz` and `p_memsz` mixed together
with the use of a loop over fragments. After recent changes it is possible to
avoid using a loop for the computation of `p_filesz`, since we know that fragments
are sorted by their file offsets.
The main benefit of this change is that splits the computation of `p_filesz`
and `p_memsz` what is simpler and allows us to fix the computation of the
`p_memsz` independently (D78005 shows the issue that we have currently).
Differential revision: https://reviews.llvm.org/D78628
It allows to simplify the current code and also
might help for the code around.
It is also consistent with what we do for another headers,
e.g. section headers, elf file header etc.
Differential revision: https://reviews.llvm.org/D78627
The `Offset` field is used to set the file offset of a program header.
In a normal object it should not be greater than the minimal offset
of sections included into segment.
This patch adds a check for that and adds tests.
Differential revision: https://reviews.llvm.org/D78304
This validates that sections listed for a segment in the YAML
declaration are ordered by their file offsets.
It might help to simplify the file size computation, but also
is useful by itself as helps to avoid issues in test cases and
to maintain their readability.
Differential revision: https://reviews.llvm.org/D78361
I've noticed that it is not convenient to create YAMLs from
binaries (using obj2yaml) that have to be test cases for obj2yaml
later (after applying yaml2obj).
The problem, for example is that obj2yaml emits "DynamicSymbols:"
key instead of .dynsym. It also does not create .dynstr.
And when a YAML document without explicitly defined .dynsym/.dynstr
is given to yaml2obj, we have issues:
1) These sections are placed after non-allocatable sections (I've fixed it in D74756).
2) They have VA == 0. User needs create descriptions for such sections explicitly manually
to set a VA.
This patch addresses (2). I suggest to let yaml2obj assign virtual addresses by itself.
It makes an output binary to be much closer to "normal" ELF.
(It is still possible to use "Address: 0x0" for a section to get the original behavior
if it is needed)
Differential revision: https://reviews.llvm.org/D74764
.dynsym and .dynstr are allocatable and therefore normally are placed
before non-allocatable .strtab, .shstrtab, .symtab sections.
But we are placing them after currently what creates a mix of
alloc/non-alloc sections and does not look normal.
Differential revision: https://reviews.llvm.org/D74756
Previously the description allowed to describe symbols with use of
`Name` and `Index` keys. This patch removes them and now it is still
possible to use either names or symbol indexes, but the code is simpler
and the format is slightly different.
Such a change will be useful for another patches, e.g:
https://reviews.llvm.org/D73788#inline-671077
Differential revision: https://reviews.llvm.org/D73888
We are missing ability to override the sh_entsize field for
SHT_REL[A] sections. It would be useful for writing test cases.
Differential revision: https://reviews.llvm.org/D73621
Note: this is a reland with a trivial 2 lines fix in ELFState<ELFT>::writeSectionContent.
It adds a check similar to ones we already have for other sections to fix the case revealed
by bots, like http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/60744.
The encoded sequence of Elf*_Relr entries in a SHT_RELR section looks
like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
i.e. start with an address, followed by any number of bitmaps. The address
entry encodes 1 relocation. The subsequent bitmap entries encode up to 63(31)
relocations each, at subsequent offsets following the last address entry.
More information is here:
https://github.com/llvm-mirror/llvm/blob/master/lib/Object/ELF.cpp#L272
This patch adds a support for these sections.
Differential revision: https://reviews.llvm.org/D71872
The encoded sequence of Elf*_Relr entries in a SHT_RELR section looks
like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
i.e. start with an address, followed by any number of bitmaps. The address
entry encodes 1 relocation. The subsequent bitmap entries encode up to 63(31)
relocations each, at subsequent offsets following the last address entry.
More information is here:
https://github.com/llvm-mirror/llvm/blob/master/lib/Object/ELF.cpp#L272
This patch adds a support for these sections.
Differential revision: https://reviews.llvm.org/D71872
Currently we have the `Flags` property that allows to
set flags for a section. The problem is that it does not
allow us to set an arbitrary value, because of bit fields
validation under the hood. An arbitrary values can be used
to test specific broken cases.
We probably do not want to relax the validation, so this
patch adds a `ShSize` property that allows to
override the `sh_size`. It is inline with others `Sh*` properties
we have already.
Differential revision: https://reviews.llvm.org/D71411
We already have Symbols property to list regular symbols and
it is currently Optional<>. This patch makes DynamicSymbols to be optional
too. With this there is no need to define a dummy symbol anymore to trigger
creation of the .dynsym and it is now possible to define an empty .dynsym using
just the following line:
DynamicSymbols: []
(it is important to have when you do not want to have dynamic symbols,
but want to have a .dynsym)
Now the code is consistent and it helped to fix a bug: previously we
did not report an error when both Content/Size and an empty
Symbols/DynamicSymbols list were specified.
Differential revision: https://reviews.llvm.org/D70956
This section contains strings specifying libraries to be added to the link by the linker.
The strings are encoded as standard null-terminated UTF-8 strings.
This patch adds a way to describe and dump SHT_LLVM_DEPENDENT_LIBRARIES sections.
I introduced a new YAMLFlowString type here. That used to teach obj2yaml to dump
them like:
```
Libraries: [ foo, bar ]
```
instead of the following (if StringRef would be used):
```
Libraries:
- foo
- bar
```
Differential revision: https://reviews.llvm.org/D70598
SHT_LLVM_LINKER_OPTIONS section contains pairs of null-terminated strings.
This patch adds support for them.
Differential revision: https://reviews.llvm.org/D69895
Currently there is no way to describe the data that is not a part of an output section.
It can be a data used to align sections or to fill the gaps with something,
or another kind of custom data. In this patch I suggest a way to describe it. It looks like that:
```
Sections:
- Type: CustomFiller
Pattern: "CCDD"
Size: 4
- Name: .bar
Type: SHT_PROGBITS
Content: "FF"
```
I.e. I've added a kind of synthetic section with a synthetic type "CustomFiller".
In the code it is called a "SyntheticFiller", which is "a synthetic section which
might be used to write the custom data around regular output sections. It does
not present in the sections header table, but it might affect the output file size and
program headers produced. Think about it as about piece of data."
`SyntheticFiller` currently has a `Pattern` field and a `Size` field + an optional `Name`.
When written, `Size` of bytes in the output will be filled with a `Pattern`.
It is possible to reference a named filler it by name from the program headers description,
just like any other normal section.
Differential revision: https://reviews.llvm.org/D69709
Before this change .symtab section was required for SHT_REL[A] section
declarations. yaml2obj automatically defined it in case when YAML document
did not have it.
With this change it is now possible to produce an object that
has a relocation section, but has no symbol table.
It simplifies the code and also it is inline with how we handle Link fields
for another special sections.
Differential revision: https://reviews.llvm.org/D69260
Currently, when we do not specify "Info" field in a YAML description
for SHT_GROUP section, yaml2obj reports an error:
"error: unknown symbol referenced: '' by YAML section '.group1'"
Also, we do not link it with a symbol table by default,
though it is what we do for AddrsigSection, HashSection, RelocationSection.
(http://www.sco.com/developers/gabi/latest/ch4.sheader.html#sh_link)
The patch fixes missings mentioned.
Differential revision: https://reviews.llvm.org/D69299
Xing GUO