Adds JSONScopedPrinter to llvm-readelf. It includes an empty
JSONELFDumper class which will be used to override any LLVMELFDumper
methods which utilize startLine() which JSONScopedPrinter cannot
provide.
This introduces a change where calls to llvm-readelf with non-ELF object
files that specify --elf-output-style=GNU will now print file summary
information where it previously didn't.
Fixes previous Windows test failure which occured due to JSON escaping
of '\' by not relying on LIT substitution.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D114225
Adds JSONScopedPrinter to llvm-readelf. It includes an empty
JSONELFDumper class which will be used to override any LLVMELFDumper
methods which utilize startLine() which JSONScopedPrinter cannot
provide.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D114225
This patch implements PAC return address signing for armv8-m. This patch roughly
accomplishes the following things:
- PAC and AUT instructions are generated.
- They're part of the stack frame setup, so that shrink-wrapping can move them
inwards to cover only part of a function
- The auth code generated by PAC is saved across subroutine calls so that AUT
can find it again to check
- PAC is emitted before stacking registers (so that the SP it signs is the one
on function entry).
- The new pseudo-register ra_auth_code is mentioned in the DWARF frame data
- With CMSE also in use: PAC is emitted before stacking FPCXTNS, and AUT
validates the corresponding value of SP
- Emit correct unwind information when PAC is replaced by PACBTI
- Handle tail calls correctly
Some notes:
We make the assembler accept the `.save {ra_auth_code}` directive that is
emitted by the compiler when it saves a register that contains a
return address authentication code.
For EHABI we need to have the `FrameSetup` flag on the instruction and
handle the `t2PACBTI` opcode (identically to `t2PAC`), so we can emit
`.save {ra_auth_code}`, instead of `.save {r12}`.
For PACBTI-M, the instruction which computes return address PAC should use SP
value before adjustment for the argument registers save are (used for variadic
functions and when a parameter is is split between stack and register), but at
the same it should be after the instruction that saves FPCXT when compiling a
CMSE entry function.
This patch moves the varargs SP adjustment after the FPCXT save (they are never
enabled at the same time), so in a following patch handling of the `PAC`
instruction can be placed between them.
Epilogue emission code adjusted in a similar manner.
PACBTI-M code generation should not emit any instructions for architectures
v6-m, v8-m.base, and for A- and R-class cores. Diagnostic message for such cases
is handled separately by a future ticket.
note on tail calls:
If the called function has four arguments that occupy registers `r0`-`r3`, the
only option for holding the function pointer itself is `r12`, but this register
is used to keep the PAC during function/prologue epilogue and clobbers the
function pointer.
When we do the tail call we need the five registers (`r0`-`r3` and `r12`) to
keep six values - the four function arguments, the function pointer and the PAC,
which is obviously impossible.
One option would be to authenticate the return address before all callee-saved
registers are restored, so we have a scratch register to temporarily keep the
value of `r12`. The issue with this approach is that it violates a fundamental
invariant that PAC is computed using CFA as a modifier. It would also mean using
separate instructions to pop `lr` and the rest of the callee-saved registers,
which would offset the advantages of doing a tail call.
Instead, this patch disables indirect tail calls when the called function take
four or more arguments and the return address sign and authentication is enabled
for the caller function, conservatively assuming the caller function would spill
LR.
This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:
https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension
The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:
https://developer.arm.com/documentation/ddi0553/latest
The following people contributed to this patch:
- Momchil Velikov
- Ties Stuij
Reviewed By: danielkiss
Differential Revision: https://reviews.llvm.org/D112429
Notes generated in OpenBSD core files provide additional information
about the kernel state and CPU registers. These notes are described
in core.5, which can be viewed here: https://man.openbsd.org/core.5
Differential Revision: https://reviews.llvm.org/D111966
The MSP430 ABI supports build attributes for specifying
the ISA, code model, data model and enum size in ELF object files.
Differential Revision: https://reviews.llvm.org/D107969
The current implementation of printAttributes makes it fiddly to extend
attribute support for new targets.
By refactoring the code so all target specific variables are
initialized in a switch/case statement, it becomes simpler to extend
attribute support for new targets.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D107968
The new ELF notes are added in clang-offload-wrapper, and llvm-readobj has to visualize them properly.
Differential Revision: https://reviews.llvm.org/D99552
The current implementation of displaying .stack_size information
presumes that each entry represents a single function but this is not
always the case. For example with the use of ICF multiple functions can
be represented with the same code, meaning that the address found in a
.stack_size entry corresponds to multiple function symbols.
This change allows multiple function names to be displayed when
appropriate.
Differential Revision: https://reviews.llvm.org/D105884
This is a follow up to https://reviews.llvm.org/D104080, and ca3bdb57fa (diff-e64a48fabe31db213a631fdc5f2acb51bdddf3f16a8fb2928784f4c579229585). The implementation of call graph profile was changed from a black box section to relocation approach. This was done to be compatible with post processing tools like strip/objcopy, and llvm equivalent. When they are invoked on object file before the final linking step with this new approach the symbol indices correctness is preserved.
The GNU binutils tools change the REL section to RELA section, unlike llvm tools. For example when strip -S is run on the ELF object files, as an intermediate step before linking. To preserve compatibility this patch extends implementation in LLD and ELFDumper to support both REL and RELA sections for call graph profile.
Reviewed By: MaskRay, jhenderson
Differential Revision: https://reviews.llvm.org/D105217
Currently, if target of s_branch instruction is in another section, it will fail with the error of undefined label. Although in this case, the label is not undefined but present in another section. This patch tries to handle this issue. So while handling fixup_si_sopp_br fixup in getRelocType, if the target label is undefined we issue an error as before. If it is defined, a new relocation type R_AMDGPU_REL16 is returned.
This issue has been reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100181 and https://bugs.llvm.org/show_bug.cgi?id=45887. Before https://reviews.llvm.org/D79943, we used to get an crash for this scenario. The crash is fixed now but the we still get an undefined label error. Jumps to other section can arise with hold/cold splitting.
A patch to handle the relocation in lld will follow shortly.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D105760
Users should generally observe no difference as long as they don't use
unintended option forms. Behavior changes:
* `-t=d` is removed. Use `-t d` instead.
* `--demangle=false` and `--demangle=0` cannot be used. Omit the option or use `--no-demangle`. Other flag-style options don't have `--no-` forms.
* `--help-list` is removed. This is a `cl::` specific option.
* llvm-readobj now supports grouped short options as well.
* `--color` is removed. This is generally not useful (only apply to errors/warnings) but was inherited from Support.
Some adjustment to the canonical forms
(usually from GNU readelf; currently llvm-readobj has too many redundant aliases):
* --dyn-syms is canonical. --dyn-symbols is a hidden alias
* --file-header is canonical. --file-headers is a hidden alias
* --histogram is canonical. --elf-hash-histogram is a hidden alias
* --relocs is canonical. --relocations is a hidden alias
* --section-groups is canonical. --elf-section-groups is a hidden alias
OptTable avoids global option collision if we decide to support multiplexing for binary utilities.
* Most one-dash long options are still supported. `-dt, -sd, -st, -sr` are dropped due to their conflict with grouped short options.
* `--section-mapping=false` (D57365) is strange but is kept for now.
* Many `cl::opt` variables were unnecessarily external. I added `static` whenever appropriate.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105532
We already have some reloc-types-elf-*.test serving the similar purpose.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105783
llvm-readobj is an internal testing tool for binary formats. Its output and
command line options do not need to be stable. It isn't supposed to be part of a
build process.
llvm-readelf was created as a user-facing utility and its interface intends to
be compatible with GNU readelf (unless there are good reasons not to).
The two tools have mostly compatible options. -s and -t are noticeable
exceptions due to history. I think the cost of keeping the inconsistency
overweighs the little history-compatible benefit and hinders transition from
cl::opt to OptTable, so let's change it.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105055
... even on targets preferring RELA. The section is only consumed by ld.lld
which can handle REL.
Follow-up to D104080 as I explained in the review. There are two advantages:
* The D104080 code only handles RELA, so arm/i386/mips32 etc may warn for -fprofile-use=/-fprofile-sample-use= usage.
* Decrease object file size for RELA targets
While here, change the relocation to relocate weights, instead of 0,1,2,3,..
I failed to catch the issue during review.
Currently when .llvm.call-graph-profile is created by llvm it explicitly encodes the symbol indices. This section is basically a black box for post processing tools. For example, if we run strip -s on the object files the symbol table changes, but indices in that section do not. In non-visible behavior indices point to wrong symbols. The visible behavior indices point outside of Symbol table: "invalid symbol index".
This patch changes the format by using R_*_NONE relocations to indicate the from/to symbols. The Frequency (Weight) will still be in the .llvm.call-graph-profile, but symbol information will be in relocation section. In LLD information from both sections is used to reconstruct call graph profile. Relocations themselves will never be applied.
With this approach post processing tools that handle relocations correctly work for this section also. Tools can add/remove symbols and as long as they handle relocation sections with this approach information stays correct.
Doing a quick experiment with clang-13.
The size went up from 107KB to 322KB, aggregate of all the input sections. Size of clang-13 binary is ~118MB. For users of -fprofile-use/-fprofile-sample-use the size of object files will go up slightly, it will not impact final binary size.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D104080
This patch uses the `getSymbolIndexForFunctionAddress` helper function to print function names for BB address map entries.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D102900
The `e_flags` contains a mixture of bitfields and regular ones, ensure all of them can be serialized and deserialized.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D100250
This patch adds a fallthrough bit to basic block metadata, indicating whether the basic block can fallthrough without taking any branches. The bit will help us avoid an intel LBR bug which results in occasional duplicate entries at the beginning of the LBR stack.
This patch uses `MachineBasicBlock::canFallThrough()` to set the bit. This is not a const method because it eventually calls `TargetInstrInfo::analyzeBranch`, but it calls this function with the default `AllowModify=false`. So we can either make the argument to the `getBBAddrMapMetadata` non-const, or we can use `const_cast` when calling `canFallThrough`. I decide to go with the latter since this is purely due to legacy code, and in general we should not allow the BasicBlock to be mutable during `getBBAddrMapMetadata`.
Reviewed By: tmsriram
Differential Revision: https://reviews.llvm.org/D96918
The current support only printed coredump notes, but most binaries also
contain notes. This change adds names for four FreeBSD-specific notes and
pretty-prints three of them:
NT_FREEBSD_ABI_TAG:
This note holds a 32-bit (decimal) integer containing the value of the
__FreeBSD_version macro, which is defined in crt1.o and will hold a value
such as 1300076 for a binary build on a FreeBSD 13 system.
NT_FREEBSD_ARCH_TAG:
A string containing the value of the build-time MACHINE_ARCH
NT_FREEBSD_FEATURE_CTL: A 32-bit flag that indicates to the kernel that
the binary wants certain bevahiour. Examples include setting
NT_FREEBSD_FCTL_ASLR_DISABLE which tells the kernel to disable ASLR.
After this change llvm-readobj also no longer decodes coredump-only
FreeBSD notes in non-coredump files. I've also converted the
note-freebsd.s test to use yaml2obj instead of llvm-mc.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D74393
Currently, if the note name is known, but the value isn't we don't print
the contents.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D74367
In binutils, the flag is defined for ELFOSABI_GNU and ELFOSABI_FREEBSD.
It can be used to mark a section as a GC root.
In practice, the flag has generic semantics and can be applied to many
EI_OSABI values, so we consider it generic.
Differential Revision: https://reviews.llvm.org/D95728
On z/OS, the following error message is not matched correctly in lit tests.
```
EDC5129I No such file or directory.
```
This patch uses a lit config substitution to check for platform specific error messages.
Reviewed By: muiez, jhenderson
Differential Revision: https://reviews.llvm.org/D95246
A simple refactoring patch which let us use `DataExtractor::getSLEB128` rather than using a lambda function.
Differential Revision: https://reviews.llvm.org/D95158
A default version (@@) is only available for defined symbols.
Currently we use "@@" for undefined symbols too.
This patch fixes the issue and improves our test case.
Differential revision: https://reviews.llvm.org/D95219
This was discussed in D93678 thread.
Currently we have one special chunk - Fill.
This patch re implements the "SectionHeaderTable" key to become a special chunk too.
With that we are able to place the section header table at any location,
just like we place sections.
Differential revision: https://reviews.llvm.org/D95140
This makes the following improvements.
For `SHT_GNU_versym`:
* yaml2obj: set `sh_link` to index of `.dynsym` section automatically.
For `SHT_GNU_verdef`:
* yaml2obj: set `sh_link` to index of `.dynstr` section automatically.
* yaml2obj: set `sh_info` field automatically.
* obj2yaml: don't dump the `Info` field when its value matches the number of version definitions.
For `SHT_GNU_verneed`:
* yaml2obj: set `sh_link` to index of `.dynstr` section automatically.
* yaml2obj: set `sh_info` field automatically.
* obj2yaml: don't dump the `Info` field when its value matches the number of version dependencies.
Also, simplifies few test cases.
Differential revision: https://reviews.llvm.org/D94956
On z/OS, the following error message is not matched correctly in lit tests. This patch updates the CHECK expression to match successfully.
```
EDC5129I No such file or directory.
```
Reviewed By: muiez
Differential Revision: https://reviews.llvm.org/D94239
Jayson Yan