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
... 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
Currently, each function name lookup is a linear iteration over all symbols defined in the object file which makes the total running time quadratic.
This patch optimizes the function name lookup by populating an **address to index** map upon the first function name lookup which is used to lookup each function name in O(1).
**impact**: For the clang binary built with `-fstack-size-section`, this improves the running time of `llvm-readobj --stack-size` from 7 minutes to 0.25 seconds.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D103072
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
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
`ELFDumper.cpp` implements the functionality that allows to get symbol versions.
It is used for dumping versioned symbols.
This helps to implement https://bugs.llvm.org/show_bug.cgi?id=48670 ("make llvm-nm -D print version names"):
we can move out and reuse the code from `ELFDumper.cpp`.
This is what this patch do: it moves the related functionality to `ELFFile<ELFT>`.
Differential revision: https://reviews.llvm.org/D94771
This addressed post commit comments for D93900.
GCC had an issue and requires placing a specialization of
`printUnwindInfo` to a namespace to compile:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480
Currently we don't support multiple SHT_SYMTAB_SHNDX sections
and the DT_SYMTAB_SHNDX tag currently.
This patch implements it and fixes the
https://bugs.llvm.org/show_bug.cgi?id=43991.
I had to introduce the `struct DataRegion` to ELF.h,
it is used to represent a region that might have no known size.
It is needed, because we don't know the size of the extended
section indices table when it is located via DT_SYMTAB_SHNDX.
In this case we still want to validate that we don't read
past the end of the file.
Differential revision: https://reviews.llvm.org/D92923
Add `this->` for `W`, which is the member of `ObjDumper`
An example of error:
readobj/ELFDumper.cpp:738:13: error: use of undeclared identifier 'W'
assert(&W.getOStream() == &llvm::fouts());
This adds the `template` keyword for 'getAsArrayRef' calls.
An example of error:
/b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/tools/llvm-readobj/ELFDumper.cpp:4491:50: error: use 'template' keyword to treat 'getAsArrayRef' as a dependent template name
for (const Elf_Rel &Rel : this->DynRelRegion.getAsArrayRef<Elf_Rel>())
This should fix bots after landing D93900.
An example of error is:
/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/tools/llvm-readobj/ELFDumper.cpp:883:8: warning: 'printSectionMapping' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
void printSectionMapping() {}
This is a refactoring for design of stuff in `ELFDumper.cpp`.
The current design of ELF dumper is far from ideal.
Currently most overridden functions (inherited from `ObjDumper`) in `ELFDumper` just forward to
the functions of `ELFDumperStyle` (which can be either `GNUStyle` or `LLVMStyle`).
A concrete implementation may be in any of `ELFDumper`/`DumperStyle`/`GNUStyle`/`LLVMStyle`.
This patch reorganizes the classes by introducing `GNUStyleELFDumper`/`LLVMStyleELFDumper`
which inherit from `ELFDumper`. The implementations are moved:
`DumperStyle` -> `ELFDumper`
`GNUStyle` -> `GNUStyleELFDumper`
`LLVMStyle` -> `LLVMStyleELFDumper`
With that we can avoid having a lot of redirection calls and helper methods.
The number of code lines changes from 7142 to 6922 (reduced by ~3%) and the
code overall looks cleaner.
Differential revision: https://reviews.llvm.org/D93900
As was mentioned in comments here:
https://reviews.llvm.org/D92636#inline-864967
we are not consistent and sometimes index things from 0, but sometimes
from 1 in warnings.
This patch fixes 2 places: messages reported for
program headers and messages reported for relocations.
Differential revision: https://reviews.llvm.org/D93805
It was discussed in D92545 that we might want to improve messages
reported when something is wrong with the stack size section.
This patch does it.
Differential revision: https://reviews.llvm.org/D93802
Currently llvm-readelf might print "OS Specific/Processor Specific/<unknown>"
hint when dumping the ELF file type. The patch teaches llvm-readobj to do the same.
This fixes https://bugs.llvm.org/show_bug.cgi?id=40868
I am removing `Object/elf-unknown-type.test` test because it is not in the right place,
it is outdated and very limited.
The `readobj/ELF/file-types.test` checks the functionality much better.
Differential revision: https://reviews.llvm.org/D93689
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
It mimics the GNU readelf where it prints a [VARIANT_PCS] for symbols
with st_other with STO_AARCH64_VARIANT_PCS.
Reviewed By: grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D93044
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
This is a change suggested in post commit comments for
D93096 (https://reviews.llvm.org/D93096#2451796).
Imagine we want to add a custom OS specific ELF file type.
For that we can update the `ElfObjectFileType` array:
```
static const EnumEntry<unsigned> ElfObjectFileType[] = {
...
{"Core", "CORE (Core file)", ELF::ET_CORE},
{"MyType", "MyType (my description)", 0xfe01},
};
```
The current code then might print:
```
OS Specific: (MyType (my description))
```
Though instead we probably would like to see a nicer output, e.g:
```
Type: MyType (my description)
```
To achieve that we can reorder the code slightly.
It is impossible to add a test I think, because we have no custom values in
the `ElfObjectFileType` array in LLVM.
Differential revision: https://reviews.llvm.org/D93217
This is related to https://bugs.llvm.org/show_bug.cgi?id=40868.
Currently we don't print `OS Specific`/``Processor Specific`/`<unknown>`
prefixes when dumping the ELF file type. This is not consistent
with GNU readelf. The patch fixes it.
Also, this patch removes the `types.test`, because we already have
`file-types.test`, which tests more cases and this patch revealed that
we have such a duplicate.
Differential revision: https://reviews.llvm.org/D93096
This changes the `printNotesHelper` to report warnings on its side when
there are errors when dumping notes.
With that we can provide more content when reporting warnings about broken notes.
Differential revision: https://reviews.llvm.org/D92636
This rewrites the logic to get rid of "ELFSymbolRef" API where possible.
This allowed to handle possible errors better, improve warnings reported and add new ones.
Also 'reportWarning' was replaced with 'reportUniqueWarning'
Differential revision: https://reviews.llvm.org/D92545
