This is a resurrection of D106421 with the change that it keeps backward-compatibility. This means decoding the previous version of `LLVM_BB_ADDR_MAP` will work. This is required as the profile mapping tool is not released with LLVM (AutoFDO). As suggested by @jhenderson we rename the original section type value to `SHT_LLVM_BB_ADDR_MAP_V0` and assign a new value to the `SHT_LLVM_BB_ADDR_MAP` section type. The new encoding adds a version byte to each function entry to specify the encoding version for that function. This patch also adds a feature byte to be used with more flexibility in the future. An use-case example for the feature field is encoding multi-section functions more concisely using a different format.
Conceptually, the new encoding emits basic block offsets and sizes as label differences between each two consecutive basic block begin and end label. When decoding, offsets must be aggregated along with basic block sizes to calculate the final offsets of basic blocks relative to the function address.
This encoding uses smaller values compared to the existing one (offsets relative to function symbol).
Smaller values tend to occupy fewer bytes in ULEB128 encoding. As a result, we get about 17% total reduction in the size of the bb-address-map section (from about 11MB to 9MB for the clang PGO binary).
The extra two bytes (version and feature fields) incur a small 3% size overhead to the `LLVM_BB_ADDR_MAP` section size.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D121346
`--symbolize-operands` already symbolizes branch targets based on the disassembly. When the object file is created with `-fbasic-block-sections=labels` (ELF-only) it will include a SHT_LLVM_BB_ADDR_MAP section which maps basic blocks to their addresses. In such case `llvm-objdump` can annotate the disassembly based on labels inferred on this section.
In contrast to the current labels, SHT_LLVM_BB_ADDR_MAP-based labels are created for every machine basic block including empty blocks and those which are not branched into (fallthrough blocks).
The old logic is still executed even when the SHT_LLVM_BB_ADDR_MAP section is present to handle functions which have not been received an entry in this section.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D124560
This patch adds necessary definitions for LoongArch ELF files, including
relocation types. Also adds initial support to ELFYaml, llvm-objdump,
and llvm-readobj in order to work with LoongArch ELFs.
Differential revision: https://reviews.llvm.org/D115859
getRelocatedSection interface should not check that the object file is
relocatable, as executable files may have relocations preserved with
`--emit-relocs` linker flag. The relocations are useful in context of post-link
binary analysis for function reference identification. For example, BOLT relies
on relocations to perform function reordering.
Reviewed By: MaskRay, jhenderson
Differential Revision: https://reviews.llvm.org/D102296
Currently, `ELFFile<ELFT>::getEntry` does not check an index of
an entry. Because of that the code might read past the end of the symbol
table silently. I've added a test to `llvm-readobj\ELF\relocations.test`
to demonstrate the possible issue. Also, I've added a unit test for
this method.
After this change, `getEntry` stops reporting the section index and
reuses the `getSectionContentsAsArray` method, which already has
all the validation needed. Our related warnings now provide
more and better context sometimes.
Differential revision: https://reviews.llvm.org/D93209
This was requested in comments for D93209:
https://reviews.llvm.org/D93209#inline-871192
D93209 fixes an issue with `ELFFile<ELFT>::getEntry`,
after what `getSymbol` starts calling `report_fatal_error` for previously
missed invalid cases.
This patch makes it return `Expected<>` and updates callers.
For few of them I had to add new `report_fatal_error` calls. But I see no
way to avoid it currently. The change would affects too many places, e.g:
`getSymbolBinding` and other methods are used from `ELFSymbolRef`
which is used in too many places across LLVM.
Differential revision: https://reviews.llvm.org/D93297
This is https://bugs.llvm.org/show_bug.cgi?id=45698.
Specification says that
"Loadable segment entries in the program header table appear
in ascending order, sorted on the p_vaddr member."
Our `toMappedAddr()` relies on this condition. This patch
adds a warning when the sorting order of loadable segments is wrong.
In this case we force segments sorting and that allows
`toMappedAddr()` to work as expected.
Differential revision: https://reviews.llvm.org/D92641
Currently it is impossible to create an instance of ELFObjectFile when the
SHT_SYMTAB_SHNDX can't be read. We error out when fail to parse the
SHT_SYMTAB_SHNDX section in the factory method.
This change delays reading of the SHT_SYMTAB_SHNDX section entries,
with it llvm-readobj is now able to work with such inputs.
Differential revision: https://reviews.llvm.org/D89379
This is the split part of D86269, which add a new ELF machine flag called EM_CSKY and related relocations.
Some target-specific flags and tests for csky can be added in follow-up patches later.
Differential Revision: https://reviews.llvm.org/D86610
This adds all missing format values that are defined in
ELFObjectFile<ELFT>::getFileFormatName().
Differential revision: https://reviews.llvm.org/D86625
Summary:
Define ELF binary code for VE and modify code where should use this new code.
Depends on D79544.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D79545
Rahman Lavaee