This patch updates the getSectionAndRelocations function to also support
CREL relocation sections. Unit tests have been added. This patch also
updates consumers to say they explicitly do not support CREL format
relocations. Subsequent patches will make the consumers work with CREL
format relocations and also add in testing support.
Reviewers: red1bluelost, MaskRay, rlavaee
Reviewed By: MaskRay
Pull Request: https://github.com/llvm/llvm-project/pull/126445
RISCV Zicfilp/Zicfiss extensions uses the `.note.gnu.property` section
to store flags indicating the adoption of features based on these
extensions. This patch enables the llvm-readobj/llvm-readelf tools to
dump these flags with the `--note` flag.
Adds support to objdump and readobj for reading the `UOP_Epilog` entries
of Windows x64 unwind v2.
`UOP_Epilog` has a weird format:
The first `UOP_Epilog` in the unwind data is the "header":
* The least-significant bit of `OpInfo` is the "At End" flag, which
signifies that there is an epilog at the very end of the associated
function.
* `CodeOffset` is the length each epilog described by the current unwind
information (all epilogs have the same length).
Any subsequent `UOP_Epilog` represents another epilog for the current
function, where `OpInfo` and `CodeOffset` are combined to a 12-bit value
which is the offset of the beginning of the epilog from the end of the
current function. If the offset is 0, then this entry is actually
padding and can be ignored.
Apologies for the large change, I looked for ways to break this up and
all of the ones I saw added real complexity. This change focuses on the
option's prefixed names and the array of prefixes. These are present in
every option and the dominant source of dynamic relocations for PIE or
PIC users of LLVM and Clang tooling. In some cases, 100s or 1000s of
them for the Clang driver which has a huge number of options.
This PR addresses this by building a string table and a prefixes table
that can be referenced with indices rather than pointers that require
dynamic relocations. This removes almost 7k dynmaic relocations from the
`clang` binary, roughly 8% of the remaining dynmaic relocations outside
of vtables. For busy-boxing use cases where many different option tables
are linked into the same binary, the savings add up a bit more.
The string table is a straightforward mechanism, but the prefixes
required some subtlety. They are encoded in a Pascal-string fashion with
a size followed by a sequence of offsets. This works relatively well for
the small realistic prefixes arrays in use.
Lots of code has to change in order to land this though: both all the
option library code has to be updated to use the string table and
prefixes table, and all the users of the options library have to be
updated to correctly instantiate the objects.
Some follow-up patches in the works to provide an abstraction for this
style of code, and to start using the same technique for some of the
other strings here now that the infrastructure is in place.
The ARM Guarded Control Stack extension (GCS) is similar to existing
shadow stack extensions for other architectures.
The core note will include which features of GCS are enabled, which have
been locked in their current state, and the stack pointer of the shadow
stack.
Note that 0x40f is NT_ARM_POE, FPMR is supported by LLDB and GCS will be
soon, POE is not at this time. So NT_ARM_POE will be added when that
work starts.
See
https://github.com/torvalds/linux/blob/master/include/uapi/linux/elf.h.
This patch introduces a new generic target, `gfx9-4-generic`. Since it doesn’t support FP8 and XF32-related instructions, the patch includes several code reorganizations to accommodate these changes.
For llvm_linux platform, define the following meaning for bits 9, 10,
11:
- bit 9: set if indirect gotos signing is enabled;
- bit 10: set if type info vtable pointer discrimination is enabled;
- bit 11: set if function pointer type discrimination is enabled.
This contains the fpmr register which was added in Armv9.5-a. This
register mainly contains controls for fp8 formats.
It was added to the Linux Kernel in
4035c22ef7.
Treat 8th bit of version value for llvm_linux platform as signed GOT
flag.
- clang: define `PointerAuthELFGOT` LangOption and set 8th bit of
`aarch64-elf-pauthabi-version` LLVM module flag correspondingly;
- llvm-readobj: print `PointerAuthELFGOT` or `!PointerAuthELFGOT` in
version description of llvm_linux platform depending on whether the flag
is set.
If both `-fptrauth-init-fini` and `-fptrauth-calls` are passed, sign
function pointers in `llvm.global_ctors` and `llvm.global_dtors` with
constant discriminator 0xD9D4
(`ptrauth_string_discriminator("init_fini")`). Additionally, if
`-fptrauth-init-fini-address-discrimination` is passed, address
discrimination is used for signing (otherwise, just constant
discriminator is used).
For address discrimination, we use it's special form since uses of
`llvm.global_{c|d}tors` are disallowed (see
`Verifier::visitGlobalVariable`) and we can't emit `getelementptr`
expressions referencing these special arrays. A signed ctor/dtor pointer
with special address discrimination applied looks like the following:
```
ptr ptrauth (ptr @foo, i32 0, i64 55764, ptr inttoptr (i64 1 to ptr))
```
It turns out that the notes section for corefiles (or really any elf
file with multiple notes) is set up in such a way for LLVM formatted
output that the JSON equivalent only has the last note since the notes
are held in a dictionary with every key being Note. This pr alters the
layout for the notes to a list of dictionaries to sidestep this issue
for JSON output. Prior to this pr a note section in the output looked
like (for LLVM output):
```
Notes [
NoteSection {
Name: <?>
Offset: 0x2148
Size: 0x1F864
Note {
Owner: CORE
Data size: 0x150
Type: NT_PRSTATUS (prstatus structure)
Description data (
0000: 06000000 00000000 00000000 06000000 |................|
...
)
}
Note {
Owner: CORE
Data size: 0x88
Type: NT_PRPSINFO (prpsinfo structure)
Description data (
0000: 02440000 00000000 04054040 00000000 |.D........@@....|
....
```
But is now:
```
NoteSections [
NoteSection {
Name: <?>
Offset: 0x2148
Size: 0x1F864
Notes [
{
Owner: CORE
Data size: 0x150
Type: NT_PRSTATUS (prstatus structure)
Description data (
0000: 06000000 00000000 00000000 06000000 |................|
...
)
}
{
Owner: CORE
Data size: 0x88
Type: NT_PRPSINFO (prpsinfo structure)
Description data (
0000: 02440000 00000000 04054040 00000000 |.D........@@....|
...
```
CREL is a compact relocation format for the ELF object file format.
This patch adds integrated assembler support (using the RELA form)
available with `llvm-mc -filetype=obj -crel a.s -o a.o`.
A dependent patch will add `clang -c -Wa,--crel,--allow-experimental-crel`.
Also add llvm-readobj support (for both REL and RELA forms) to
facilitate testing the assembler. Additionally, yaml2obj gains support
for the RELA form to aid testing with llvm-readobj.
We temporarily assign the section type code 0x40000020 from the generic
range to `SHT_CREL`. We avoided using `SHT_LLVM_` or `SHT_GNU_` to
avoid code churn and maintain broader applicability for interested psABIs.
Similarly, `DT_CREL` is temporarily 0x40000026.
LLVM will change the code and break compatibility. This is not an issue
if all relocatable files using CREL are regenerated (aka no prebuilt
relocatable files).
Link: https://discourse.llvm.org/t/rfc-crel-a-compact-relocation-format-for-elf/77600
Pull Request: https://github.com/llvm/llvm-project/pull/91280
In the context of #95976 it became clear that the output for readobj
implied multi valued entries in several cases in the elf headers that
the documentation only allowed for a single value. DT_NEEDED is the
example here where the value is an offset into the string table without
any sort of separator that could give you multiple entries. This patch
alters the LLVM output so that the single valued nature is emphasized.
For example the output was:
```
DynamicSection [ (35 entries)
Tag Type Name/Value
0x000000000000001D RUNPATH Library runpath: [$ORIGIN/../lib:]
0x0000000000000001 NEEDED Shared library: [libm.so.6]
0x0000000000000001 NEEDED Shared library: [libz.so.1]
0x0000000000000001 NEEDED Shared library: [libzstd.so.1]
```
and is now
```
Tag Type Name/Value
0x000000000000001D RUNPATH Library runpath: [$ORIGIN/../lib:]
0x0000000000000001 NEEDED Shared library: libm.so.6
0x0000000000000001 NEEDED Shared library: libz.so.1
0x0000000000000001 NEEDED Shared library: libzstd.so.1
```
This pr also tests that multi-valued rpaths are handled correctly in the
JSON case (i.e. they become proper lists) like:
```
{
"Tag": 15,
"Type": "RPATH",
"Value": 9,
"Path": [
"x",
"w",
"U"
]
},
```
when separated by :
When printing JSON output with --dynamic-table I noticed that the output
is invalid JSON. This patch overrides the printDynamicTable() function
in the JSONELFDumper to return a list of dictionaries for the
DynamicSection value.
Before the output was:
```
{
"FileSummary": {
"File": "bin/llvm-readelf",
"Format": "elf64-x86-64",
"Arch": "x86_64",
"AddressSize": "64bit",
"LoadName": "<Not found>"
}DynamicSection [ (35 entries)
Tag Type Name/Value
0x000000000000001D RUNPATH Library runpath: [$ORIGIN/../lib:]
0x0000000000000001 NEEDED Shared library: [libm.so.6]
0x0000000000000001 NEEDED Shared library: [libz.so.1]
0x0000000000000001 NEEDED Shared library: [libzstd.so.1]
```
Now the output looks like:
```
"DynamicSection": [
{
"Tag": 29,
"Type": "RUNPATH",
"Value": 6322,
"Path": [
"$ORIGIN/../lib"
]
},
{
"Tag": 1,
"Type": "NEEDED",
"Value": 6109,
"Library": "libm.so.6"
},
```
## Consistent PDB GUID in `llvm-readobj`
Currently, the PDB GUID is shown as a byte array:
`PDBGUID: (D8 4C 88 D9 26 15 1F 11 4C 4C 44 20 50 44 42 2E)`
This is inconsistent with `llvm-pdbutil` (e.g. `llvm-pdbutil dump
--summary`) which shows it as a hexadecimal string.
Additionally, `yaml2obj` uses the same hexadecimal string format.
In general, the hexadecimal string is the common representation for PDB
GUIDs on Windows.
This PR changes it to be consistent as shown below:
`PDBGUID: {D9884CD8-1526-111F-4C4C-44205044422E}`
This patch fixes an issue where, when printing corefile notes with
llvm-readobj as json, the dumper generated llvm formatted output which
isn't valid json. This alters the dumper to, in the NT_FILE, note, dump
properly formatted json data.
Prior to this patch the JSON output was formatted like:
```
"Mapping": [
"Start": 4096,
"End": 8192,
"Offset": 12288,
"Filename": "/path/to/a.out"
],
```
Whereas now it is formatted as:
```
"Mappings": [
{
"Start": 4096,
"End": 8192,
"Offset": 12288,
"Filename": "/path/to/a.out"
},
```
Which is valid. Additionally the LLVM output has changed to match the
structure of the JSON output (i.e. instead of lists of keys it is a list
of dictionaries)
https://reviews.llvm.org/D47919 dumped RELR relocations as
`R_*_RELATIVE` and added --raw-relr (not in GNU) for testing purposes
(more readable than `llvm-readelf -x .relr.dyn`). The option is obsolete
after `llvm-readelf -r` output gets improved (#89162).
Since --raw-relr never seems to get more adoption. Let's remove it to
avoid some complexity.
Pull Request: https://github.com/llvm/llvm-project/pull/89426
llvm-readelf/llvm-readobj print RELR as REL relocations with a fixed
type (e.g. `R_*_RELATIVE`). GNU readelf printed only addresses and have
recently switched to a more descritive style that includes a symbolic
address column (symbolized using .symtab/.strtab) (milestone: binutils
2.43).
This patch implements the new GNU style, which seems superior to the
current REL style and essentially obsoletes LLVM-specific --raw-relr
(`printRelrReloc`).
Pull Request: https://github.com/llvm/llvm-project/pull/89162
Reland #85231 after fixing build failure
https://lab.llvm.org/buildbot/#/builders/186/builds/15631.
Use `PRIx64` for format output of `uint64_t` as hex.
Original PR description below.
This adds support for `GNU_PROPERTY_AARCH64_FEATURE_PAUTH` feature (as
defined in https://github.com/ARM-software/abi-aa/pull/240) handling in
llvm-readobj and llvm-readelf. The following constants for supported
platforms are also introduced:
- `AARCH64_PAUTH_PLATFORM_INVALID = 0x0`
- `AARCH64_PAUTH_PLATFORM_BAREMETAL = 0x1`
- `AARCH64_PAUTH_PLATFORM_LLVM_LINUX = 0x10000002`
For the llvm_linux platform, output of the tools contains descriptions
of PAuth features which are enabled/disabled depending on the version
value. Version value bits correspond to the following `LangOptions`
defined in #85232:
- bit 0: `PointerAuthIntrinsics`;
- bit 1: `PointerAuthCalls`;
- bit 2: `PointerAuthReturns`;
- bit 3: `PointerAuthAuthTraps`;
- bit 4: `PointerAuthVTPtrAddressDiscrimination`;
- bit 5: `PointerAuthVTPtrTypeDiscrimination`;
- bit 6: `PointerAuthInitFini`.
Support for `.note.AARCH64-PAUTH-ABI-tag` is dropped since it's deleted
from the spec in ARM-software/abi-aa#250.
This adds support for `GNU_PROPERTY_AARCH64_FEATURE_PAUTH` feature (as
defined in https://github.com/ARM-software/abi-aa/pull/240) handling in
llvm-readobj and llvm-readelf. The following constants for supported
platforms are also introduced:
- `AARCH64_PAUTH_PLATFORM_INVALID = 0x0`
- `AARCH64_PAUTH_PLATFORM_BAREMETAL = 0x1`
- `AARCH64_PAUTH_PLATFORM_LLVM_LINUX = 0x10000002`
For the llvm_linux platform, output of the tools contains descriptions
of PAuth features which are enabled/disabled depending on the version
value. Version value bits correspond to the following `LangOptions`
defined in #85232:
- bit 0: `PointerAuthIntrinsics`;
- bit 1: `PointerAuthCalls`;
- bit 2: `PointerAuthReturns`;
- bit 3: `PointerAuthAuthTraps`;
- bit 4: `PointerAuthVTPtrAddressDiscrimination`;
- bit 5: `PointerAuthVTPtrTypeDiscrimination`;
- bit 6: `PointerAuthInitFini`.
Support for `.note.AARCH64-PAUTH-ABI-tag` is dropped since it's deleted
from the spec in ARM-software/abi-aa#250.
`TargetEndianness` is long and unwieldy. "Target" in the name is confusing. Rename it to "Endianness".
I cannot find noticeable out-of-tree users of `TargetEndianness`, but
keep `TargetEndianness` to make this patch safer. `TargetEndianness`
will be removed by a subsequent change.
Defines a subset of attributes and emits them to a section called
.hexagon.attributes.
The current attributes recorded are the attributes needed by
llvm-objdump to automatically determine target features and eliminate
the need to manually pass features.
GNU readelf prints a blank line before the first hex/string dump, which
serves as a separator when there are other dump operations. Port the
behavior.
Pull Request: https://github.com/llvm/llvm-project/pull/85744
When dumping FDEs, `readelf` prints new location values after
`DW_CFA_advance_loc(*)` instructions, which looks quite convenient:
```
> readelf -wf test.o
...
... FDE ... pc=0000000000000030..0000000000000064
DW_CFA_advance_loc: 4 to 0000000000000034
...
DW_CFA_advance_loc: 4 to 0000000000000038
...
```
This patch makes `llvm-dwarfdump` and `llvm-readobj` do the same.
Primary change is to add a flag `--pretty-pgo-analysis-map` to
llvm-readobj and llvm-objdump that prints block frequencies and branch
probabilities in the same manner as BFI and BPI respectively. This can
be helpful if you are manually inspecting the outputs from the tools.
In order to print, I moved the `printBlockFreqImpl` function from
Analysis to Support and renamed it to `printRelativeBlockFreq`.
When a section has the SHF_COMPRESSED flag, -p/-x dump the compressed
content by default. In GNU readelf, if --decompress/-z is specified,
-p/-x will dump the decompressed content. This patch implements the
option.
Close#82507
Linux kernel fs/binfmt_elf_fdpic.c supports FDPIC for MMU-less systems.
GCC/binutils/qemu support FDPIC ABI for ARM
(https://github.com/mickael-guene/fdpic_doc).
_ARM FDPIC Toolchain and ABI_ provides a summary.
This patch implements FDPIC relocations to the integrated assembler.
There are 6 static relocations and 2 dynamic relocations, with
R_ARM_FUNCDESC as both static and dynamic.
gas requires `--fdpic` to assemble data relocations like `.word f(FUNCDESC)`.
This patch adds `MCTargetOptions::FDPIC` and reports an error if FDPIC
is not set.
Pull Request: https://github.com/llvm/llvm-project/pull/82187
The section headers for XCOFF files have a subtype flag for Dwarf
sections. This PR updates obj2yaml, yaml2obj, and llvm-readobj so that
they recognize the subtype.
