Commit Graph

188 Commits

Author SHA1 Message Date
Alexander Shaposhnikov 10af5bad44 [llvm-objcopy] Consolidate and unify version tests
In this diff the tests which verify version printing functionality are refactored.
Since they are not specific to a particular format we move them into tool-version.test
and slightly unify (similarly to tool-name.test and tool-help-message.test).

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D87211
2020-09-07 18:44:32 -07:00
Alexandre Ganea a680ea2c72 Fix "last accessed time" test failing on Windows
Before this patch, the tests in llvm/test/tools/llvm-objcopy/ELF/strip-preserve-atime.test used to fail on my machine, because the "last accessed time" is disabled in the OS by default since Windows XP. One needs to explicitly enable it for the feature to work. Otherwise the last access time is the last write time. Please see: https://superuser.com/questions/251263/the-last-access-date-is-not-changed-even-after-reading-the-file-on-windows-7

    Differential Revision: https://reviews.llvm.org/D85669
2020-08-10 16:03:14 -04:00
Fangrui Song dd405f1a53 Revert D83834 "Add test utility 'extract'"
This reverts commit d054c7ee2e.

There are discussions about the utility name, its functionality and user interface.
Revert before we reach consensus.
2020-07-28 13:26:33 -07:00
Fangrui Song d054c7ee2e Add test utility 'extract'
See https://lists.llvm.org/pipermail/llvm-dev/2020-July/143373.html
"[llvm-dev] Multiple documents in one test file" for some discussions.

`extract part filename` splits the input file into multiple parts separated by
regex `^(.|//)--- ` and extract the specified part to stdout or the
output file (if specified).

Use case A (organizing input of different formats (e.g. linker
script+assembly) in one file).

```
// RUN: extract lds %s -o %t.lds
// RUN: extract asm %s -o %t.s
// RUN: llvm-mc %t.s -o %t.o
// RUN: ld.lld -T %t.lds %t.o -o %t
This is sometimes better than the %S/Inputs/ approach because the user
can see the auxiliary files immediately and don't have to open another file.
```

Use case B (for utilities which don't have built-in input splitting
feature):

```
// RUN: extract case1 %s | llc | FileCheck %s --check-prefix=CASE1
// RUN: extract case2 %s | llc | FileCheck %s --check-prefix=CASE2
Combing tests prudently can improve readability.
This is sometimes better than having multiple test files.
```

Since this is a new utility, there is no git history concerns for
UpperCase variable names. I use lowerCase variable names like mlir/lld.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D83834
2020-07-23 19:15:35 -07:00
Georgy Komarov afd81a637d
[llvm-objcopy] Fix crash when removing symbol table at same time as adding a symbol
This patch resolves crash that occurs when user wanted to remove all
symbols and add a brand new one using:

```
llvm-objcopy -R .symtab --add-symbol foo=1234 in.o out.o
```

Before these changes the symbol table internally being null when adding
new symbols. For now we will regenerate symtab in this case.

This fixes: https://bugs.llvm.org/show_bug.cgi?id=43930

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D82935
2020-07-05 05:14:00 +03:00
Georgy Komarov e503851d80 [llvm-objcopy] Emit error if removing symtab referenced by group section
SHT_GROUP sections contain a reference to a symbol indicating their
"signature" symbol. The symbol table containing this symbol is referred
to by the group section's sh_link field. If llvm-objcopy is instructed
to remove the symbol table, it will emit an error.

This fixes https://bugs.llvm.org/show_bug.cgi?id=46153.

Reviewed By: jhenderson, Higuoxing

Differential Revision: https://reviews.llvm.org/D82274
2020-06-29 10:42:03 +01:00
Sid Manning e5911de377 [Hexagon][llvm-objcopy] Add missing check for SHN_HEXAGON_SCOMMON_1
Differential Revision: https://reviews.llvm.org/D82484
2020-06-24 19:56:01 -05:00
Alexander Shaposhnikov 395920a614 [llvm-objcopy] Update help message tests
This diff merges help message tests for llvm-objcopy, llvm-strip and
llvm-install-name-tool.

Patch by Sameer Arora!

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D82012
2020-06-24 12:40:31 -07:00
Alexander Shaposhnikov ca133cdecf [llvm-objcopy] Update help messages
This diff updates the help messages for llvm-objcopy, llvm-strip and
llvm-install-name-tool.

Patch by Sameer Arora!

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D81907
2020-06-24 11:19:56 -07:00
Georgii Rymar 818ab3d654 [yaml2obj] - Allocate the file space for SHT_NOBITS sections in some cases.
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
2020-06-11 12:54:53 +03:00
Sameer Arora a018b538a6 [llvm-objcopy] Reorder --dump-section before --remove-section for ELF
Reorder `DumpSection` under `handleArgs` in file `ELFObjcopy.cpp`.
`DumpSection` is placed before `replaceAndRemoveSections` and is
therefore now the first operation under `handleArgs`. Thus, it is now
performed before both `add` and `remove` section operations.

Change for the MachO format at D81123. Together fixes https://bugs.llvm.org/show_bug.cgi?id=44283.

Reviewed By: alexshap, jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D81097
2020-06-05 10:45:51 -07:00
Georgii Rymar 5750f12b82 Revert "[yaml2obj] - Allocate the file space for SHT_NOBITS sections in some cases."
This reverts commit aa3a85cdaa.

There are problems with it. See here: https://reviews.llvm.org/D80629
2020-06-04 13:17:48 +03:00
Georgii Rymar aa3a85cdaa [yaml2obj] - Allocate the file space for SHT_NOBITS sections in some cases.
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
2020-06-02 17:19:24 +03:00
Igor Kudrin 5b875bf59b [llvm-objcopy][ELF] Fix removing a group member.
When a group member is removed, the corresponding record in the
SHT_GROUP section has to be deleted.

This fixes PR46064.

Differential Revision: https://reviews.llvm.org/D80568
2020-05-29 20:24:53 +07:00
Igor Kudrin a9313282cd [llvm-objcopy][ELF] Fix removing SHT_GROUP sections.
When a SHT_GROUP section is removed, but other sections of the group are
kept, the SHF_GROUP flag of these sections should be dropped, otherwise
the resulting ELF file will be malformed.

Differential Revision: https://reviews.llvm.org/D80511
2020-05-29 20:24:53 +07:00
Georgii Rymar e2b134b01a [yaml2obj] - Stop using square brackets for unique suffixes.
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
2020-05-19 12:59:13 +03:00
Fangrui Song 32b19334da [llvm-objcopy][ELF] Allow --dump-section to dump an empty non-SHT_NOBITS section
This is the ELF part of D75949.

GNU objcopy from binutils 2.35 onwards will support an empty non-SHT_NOBITS section as
well
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=e052e2ba295a65b6ea80cbc3f90495beca299c42

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D79339
2020-05-05 08:26:34 -07:00
Fangrui Song a11e90a6b9 [llvm-objcopy][test] ELF/dump-section.test: change #CHECK to # CHECK
The latter is more common and thus the preferred way to use CHECK lines.
2020-05-05 08:26:34 -07:00
Fangrui Song ec786906f5 [llvm-objcopy] -O binary: skip empty sections
After SHF_ALLOC sections are ordered by LMA:

* If initial sections are empty, GNU objcopy skips their contents while we
  emit leading zeros. (binary-paddr.test %t4)
* If trailing sections are empty, GNU objcopy skips their contents while we
  emit trailing zeros. (binary-paddr.test %t5)

This patch matches GNU objcopy's behavior. Linkers don't keep p_memsz
PT_LOAD segments. Such empty sections would not have a containing
PT_LOAD and `Section::ParentSegment` might be null if linkers fail to
optimize the file offsets (lld D79254).

In particular, without D79254, the arm Linux kernel's multi_v5_defconfig
depends on this behavior: in `vmlinux`, an empty .text_itcm is mapped at
a very high address (0xfffe0000) but the kernel does not expect
`objcopy -O binary` to create a very large `arch/arm/boot/Image`
(0xfffe0000-0xc0000000 ~= 1GiB). See https://bugs.llvm.org/show_bug.cgi?id=45632

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D79229
2020-05-01 14:25:37 -07:00
Fangrui Song fd624e623d [llvm-objcopy] Don't specialize the all zero p_paddr case
Spotted by https://reviews.llvm.org/D74755#1998673

> it looks like OrderedSegments in the function is only used to set the physical address to the virtual address when there are no physical addresses set amongst these sections.

I believe this behavior was copied from https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=6ffd79000b45e77b3625143932ffbf781b6aecab (2008-05)
The commit was made for some corner cases of very old linkers.
This special rule does not seem useful and remove it can allow us to
delete a large chunk of code.

Reviewed By: jhenderson, jakehehrlich

Differential Revision: https://reviews.llvm.org/D78786
2020-04-27 11:20:41 -07:00
Georgii Rymar 2bf5674317 [yaml2obj] - Program headers: add an additional check for `Offset`
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
2020-04-22 12:49:05 +03:00
Fangrui Song b14e9e3c0c Reland D76675 [llvm-objcopy] Match GNU behaviour regarding file symbols
Don't error on Config.KeepFileSymbols for COFF and Mach-O.

Original description:

GNU objcopy removes STT_FILE symbols for strip-debug operations, and
keeps them for --discard-all operation. Match their behaviour for
llvm-objcopy.

Bug: https://github.com/android/ndk/issues/1212

Differential Revision: https://reviews.llvm.org/D76675
2020-04-20 21:18:48 -07:00
Yi Kong 37a1c2eda5 Revert "[llvm-objcopy] Match GNU behaviour regarding file symbols"
This reverts commit 7c65e88d0b.

Broke non ELF targets.
2020-04-21 12:04:01 +08:00
Yi Kong 7c65e88d0b [llvm-objcopy] Match GNU behaviour regarding file symbols
GNU objcopy removes STT_FILE symbols for strip-debug operations, and
keeps them for --discard-all operation. Match their behaviour for
llvm-objcopy.

Bug: https://github.com/android/ndk/issues/1212

Differential Revision: https://reviews.llvm.org/D76675
2020-04-21 11:30:04 +08:00
Bill Wendling edcfc391e1 [Object] Use BFD name for little-endian PowerPC64
Summary:
Little-endian PowerPC object files should report "elf64-powerpcle" instead of
"elf64-powerpc".

Reviewers: jhenderson, MaskRay, espindola, alexshap, rupprecht, #powerpc

Reviewed By: MaskRay

Subscribers: wuzish, emaste, nemanjai, shchenz, steven.zhang, llvm-commits

Tags: #llvm, #powerpc

Differential Revision: https://reviews.llvm.org/D78344
2020-04-19 20:10:05 -07:00
Georgii Rymar b6d77e792c [tools][tests] - Use --check-prefixes instead of multiple --check-prefix. NFCI.
There is no need to use `--check-prefix` multiple times.
It helps to improve readability/test maintainability.
This patch does it for all tools at once.

Differential revision: https://reviews.llvm.org/D78217
2020-04-17 12:35:25 +03:00
Georgii Rymar 82bfe3b177 [LLVM/tools][test] - Remove/fix dead check prefixes.
We have a few unused/broken FileCheck prefixes in `llvm/test/tools`.
This patch fixes it.

Differential revision: https://reviews.llvm.org/D78110
2020-04-15 13:09:51 +03:00
Sid Manning 5002863ab0 Support bfdname "elf32-hexagon".
Add support and update testcases.

Differential Revision: https://reviews.llvm.org/D77579
2020-04-06 17:22:56 -05:00
James Henderson ccf16c4d38 Make test more robust
llvm-readobj prints the file path as part of the output, so
--implicit-check-not patterns can accidentally match it. This patch
makes the test more robust by preventing failures if "foo" is in
somebody's path.

Reviewed by: grimar

Differential Revision: https://reviews.llvm.org/D77546
2020-04-06 14:47:05 +01:00
Vedant Kumar 5e6e545cba [test] Re-enable accidentally disabled X86 tests
A number of X86 tests were accidentally disabled in
https://reviews.llvm.org/D73568. This commit re-enables those tests.

```
$ for x86_test in $(gg 'REQUIRES: x86$' llvm/test | fst); do sed -i "" '/REQUIRES: x86/d' $x86_test; done
```

(Note that 'x86' is not an available feature, that's what caused the
tests to be disabled.)
2020-03-19 09:29:23 -07:00
Fangrui Song 536ba6373f [Object] Change ELFObjectFile<ELFT>::getFileFormatName() to use BFD names
Follow-up for D74433

What the function returns are almost standard BFD names, except that "ELF" is
in uppercase instead of lowercase.

This patch changes "ELF" to "elf" and changes ARM/AArch64 to use their BFD names.
MIPS and PPC64 have endianness differences as well, but this patch does not intend to address them.

Advantages:

* llvm-objdump: the "file format " line matches GNU objdump on ARM/AArch64 objects
* "file format " line can be extracted and fed into llvm-objcopy -O literally.
  (https://github.com/ClangBuiltLinux/linux/issues/779 has such a use case)

Affected tools: llvm-readobj, llvm-objdump, llvm-dwarfdump, MCJIT (internal implementation detail, not exposed)

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D76046
2020-03-16 07:42:04 -07:00
Georgii Rymar b236b4cb43 [yaml2obj] - Set a default value for `PAddr` property of a program header to a value of `VAddr`
`PAddr` corresponds to `p_paddr` of a program header, which is the segment's physical
address for systems in which physical addressing is relevant. `p_paddr` is often equal
to `p_vaddr`, which is the virtual address of a segment.

This patch changes the default for `PAddr` from 0 to a value of `VAddr`.

Differential revision: https://reviews.llvm.org/D76131
2020-03-14 17:44:57 +03:00
Jordan Rupprecht c140810ea1 [llvm-readobj] Include section name of notes.
This changes the output of `llvm-readelf -n` from:

```
Displaying notes found at file offset 0x<...> with length 0x<...>:
```

to:

```
Displaying notes found in: .note.foo
```

And similarly, adds a `Name:` field to the `llvm-readobj -n` output for notes.

This change not only increases GNU compatibility, it also makes it much easier to read notes. Note that we still fall back to printing the file offset/length in cases where we don't have a section name, such as when printing notes in program headers or printing notes in a partially stripped file (GNU readelf does the same).

Fixes llvm.org/PR41339.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D75647
2020-03-05 09:53:14 -08:00
Fangrui Song 9e1319df7e [llvm-readelf] Make --all output order closer to GNU readelf
https://bugs.llvm.org/show_bug.cgi?id=43403

The new order makes it easy to compare the two tools' --all.

Reviewed By: grimar, rupprecht

Differential Revision: https://reviews.llvm.org/D75592
2020-03-04 12:22:12 -08:00
Fangrui Song 6503aadcc6 [llvm-objcopy][test] Improve empty section tests
empty-sections.test: add two tests adapted from @jhenderson's https://reviews.llvm.org/D74755#1882221
strip-non-alloc.test: improve. D74755 will change the attribution of an empty section.

They mostly test the behavior of Object.cpp:sectionWithinSegment : how we attribute sections to segments.
`ParentSegment` can affect some subtle layout decisions.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D74879
2020-02-26 08:57:23 -08:00
Georgii Rymar 31f2ad9c36 [yaml2obj] - Automatically assign sh_addr for allocatable sections.
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
2020-02-22 14:43:54 +03:00
Georgii Rymar 3439d4ee0e [yaml2obj] - Change the order of implicitly created sections.
.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
2020-02-19 15:09:19 +03:00
Fangrui Song 200ac6c3d8 [llvm-objcopy][test] Fix tests when path contains "bar"
Differential Revision: https://reviews.llvm.org/D72358
2020-01-30 17:56:12 -08:00
Fangrui Song 55c81d4282 [test] Use yaml2obj -o %t instead of > %t
To improve consistency and avoid unneeded shell feature (output
redirection).

While here, make other changes to improve consistency

--docnum 1 => --docnum=1
-docnum=x => --docnum=x
2020-01-21 17:20:18 -08:00
Sergey Dmitriev e446322f73 [llvm-objcopy][ELF] Allow setting SHF_EXCLUDE flag for ELF sections
Summary: This patch adds support for setting SHF_EXCLUDE flag for ELF sections.

Reviewers: jhenderson, grimar, MaskRay, mstorsjo, espindola, alexshap, rupprecht

Reviewed By: jhenderson, MaskRay

Subscribers: emaste, abrachet, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72128
2020-01-20 18:56:45 -08:00
Fangrui Song 896b84ac2c [llvm-readelf] Print EI_ABIVERSION as decimal instead of hexadecimal
This matches GNU readelf and llvm-readobj.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D72234
2020-01-06 09:25:45 -08:00
Georgii Rymar 541daa5e6b [llvm-readelf][llvm-readobj] - Reimplement the logic of section flags dumping.
Our logic that dumped the flags was buggy.

For LLVM style it dumped SHF_MASKPROC/SHF_MASKOS named constants, though
they are not flags, but masks.

For GNU style it was just very inconsistent with GNU which has logic
that is not straightforward. Imagine we have sh_flags == 0x90000000.
SHF_EXCLUDE ("E") has a value of 0x80000000 and SHF_MASKPROC is 0xf0000000.
GNU readelf will not print "E" or "Ep" in this case, but will print just
"p". It only will print "E" when no other processor flag is set.
I had to investigate the GNU source to find the algorithm and now our logic should
match it.

Differential revision: https://reviews.llvm.org/D71462
2019-12-18 10:44:40 +03:00
Fangrui Song d28c6d51d1 [llvm-objcopy][ELF] -O binary: use LMA instead of sh_offset to decide where to write section contents
.text sh_address=0x1000 sh_offset=0x1000
.data sh_address=0x3000 sh_offset=0x2000

In an objcopy -O binary output, the distance between two sections equal
their LMA differences (0x3000-0x1000), instead of their sh_offset
differences (0x2000-0x1000). This patch changes our behavior to match
GNU.

This rule gets more complex when the containing PT_LOAD has
p_vaddr!=p_paddr. GNU objcopy essentially computes
sh_offset-p_offset+p_paddr for each candidate section, and removes the
gap before the first address.

Added tests to binary-paddr.test to catch the compatibility problem.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D71035
2019-12-15 21:45:25 -08:00
Fangrui Song 7af6025bd1 [llvm-objcopy][COFF] Implement --redefine-sym and --redefine-syms
The parsing error tests in ELF/redefine-symbols.test are not specific to ELF.
Move them to redefine-symbols.test.
Add COFF/redefine-symbols.test for COFF specific tests.

Also fix the documentation regarding --redefine-syms: the old and new
names are separated by whitespace, not an equals sign.

Reviewed By: mstorsjo

Differential Revision: https://reviews.llvm.org/D70036
2019-11-12 11:28:00 -08:00
Fangrui Song 5ad0103d8a [llvm-objcopy][ELF] Implement --only-keep-debug
--only-keep-debug produces a debug file as the output that only
preserves contents of sections useful for debugging purposes (the
binutils implementation preserves SHT_NOTE and non-SHF_ALLOC sections),
by changing their section types to SHT_NOBITS and rewritting file
offsets.

See https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html

The intended use case is:

```
llvm-objcopy --only-keep-debug a a.dbg
llvm-objcopy --strip-debug a b
llvm-objcopy --add-gnu-debuglink=a.dbg b
```

The current layout algorithm is incapable of deleting contents and
shrinking segments, so it is not suitable for implementing the
functionality.

This patch adds a new algorithm which assigns sh_offset to sections
first, then modifies p_offset/p_filesz of program headers. It bears a
resemblance to lld/ELF/Writer.cpp.

Reviewed By: jhenderson, jakehehrlich

Differential Revision: https://reviews.llvm.org/D67137
2019-11-05 08:56:15 -08:00
Fangrui Song 27cb352fd2 [llvm-objcopy] --add-symbol: address post-commit reviews of D69093
* Improve comments.
* Reorder the assignment to Obj.SectionNames before the symbol table
  creation code. Add a test.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D69526
2019-10-31 09:12:06 -07:00
James Henderson fb4a55010e [llvm-objcopy] Preserve .ARM.attributes section when stripping files
This works around a bug in Debian's patchset for glibc. The bug is
described in detail in the upstream debian bug:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=943798, but the short
version of it is that glibc on any Debian based distro don't load
libraries unless it has a .ARM.attribute section.

Reviewed by: jhenderson, rupprecht, MaskRay, jakehehrlich

Differential Revision: https://reviews.llvm.org/D69188

Patch by Tobias Hieta.
2019-10-31 11:57:19 +00:00
Georgii Rymar a795bd9645 [llvm-objcopy] - Do not crash on object that has relocations but no symbol table.
It was revealed by D69260.

Tool crashed when scanned relocations in a object without a symbol table.
This patch teaches it either to handle such objects (when relocations
does not use symbols we do not need a symbol table to proceed)
or to show an appropriate error otherwise.

Differential revision: https://reviews.llvm.org/D69304
2019-10-30 13:17:22 +03:00
Georgii Rymar 3fe7f1dcf4 [yaml2obj] - Make .symtab to be not mandatory section for SHT_REL[A] section.
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
2019-10-29 11:43:12 +03:00
georgerim de3cef1d5d [yaml2obj, obj2yaml] - Add support for SHT_NOTE sections.
SHT_NOTE is the section that consists of
namesz, descsz, type, name + padding, desc + padding data.
This patch teaches yaml2obj, obj2yaml to dump and parse them.

This patch implements the section how it is described here:
https://docs.oracle.com/cd/E23824_01/html/819-0690/chapter6-18048.html
Which says: "For 64–bit objects and 32–bit objects, each entry is an array of 4-byte words in
the format of the target processor"

The official specification is different
http://www.sco.com/developers/gabi/latest/ch5.pheader.html#note_section
And says: "n 64-bit objects (files with e_ident[EI_CLASS] equal to ELFCLASS64), each entry is an array
of 8-byte words in the format of the target processor. In 32-bit objects (files with e_ident[EI_CLASS]
equal to ELFCLASS32), each entry is an array of 4-byte words in the format of the target processor"

Since LLVM uses the first, 32-bit way, this patch follows it.

Differential revision: https://reviews.llvm.org/D68983
2019-10-25 13:25:56 +03:00