`struct Elf*_Shdr` has a field `sh_offset`, named `ShOffset` in
llvm::ELFYAML::Section. Rename SHOffset (e_shoff) to SHOff to prevent confusion.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D67254
llvm-svn: 371185
See http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html
and D60242 for the lld partition feature.
This patch:
* Teaches yaml2obj to parse the 3 section types.
* Teaches llvm-readobj/llvm-readelf to dump the 3 section types.
There is no test for SHT_LLVM_DEPENDENT_LIBRARIES in llvm-readobj. Add
it as well.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D67228
llvm-svn: 371157
Fix: added missing return "return 0;"
Original commit message:
This eliminates one of the error(1) call in this lib.
It is different from the others because happens on a fields mapping stage
and can be easily fixed.
Differential revision: https://reviews.llvm.org/D67150
llvm-svn: 371030
This eliminates one of the error(1) call in this lib.
It is different from the others because happens on a fields mapping stage
and can be easily fixed.
Differential revision: https://reviews.llvm.org/D67150
llvm-svn: 371023
PT_GNU_STACK is used in an llvm-objcopy test.
I plan to use PT_GNU_RELRO in a patch to improve nested segment
processing in llvm-objcopy (PR42963).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D67146
llvm-svn: 370857
This is in line with the previous changes which allowed to
override the sh_offset/sh_size and useful for writing test cases.
Differential revision: https://reviews.llvm.org/D66998
llvm-svn: 370633
Currenly we can encode the 'st_other' field of symbol using 3 fields.
'Visibility' is used to encode STV_* values.
'Other' is used to encode everything except the visibility, but it can't handle arbitrary values.
'StOther' is used to encode arbitrary values when 'Visibility'/'Other' are not helpfull enough.
'st_other' field is used to encode symbol visibility and platform-dependent
flags and values. Problem to encode it is that it consists of Visibility part (STV_* values)
which are enumeration values and the Other part, which is different and inconsistent.
For MIPS the Other part contains flags for all STO_MIPS_* values except STO_MIPS_MIPS16.
(Like comment in ELFDumper says: "Someones in their infinite wisdom decided to make
STO_MIPS_MIPS16 flag overlapped with other ST_MIPS_xxx flags."...)
And for PPC64 the Other part might actually encode any value.
This patch implements custom logic for handling the st_other and removes
'Visibility' and 'StOther' fields.
Here is an example of a new YAML style this patch allows:
- Name: foo
Other: [ 0x4 ]
- Name: bar
Other: [ STV_PROTECTED, 4 ]
- Name: zed
Other: [ STV_PROTECTED, STO_MIPS_OPTIONAL, 0xf8 ]
Differential revision: https://reviews.llvm.org/D66886
llvm-svn: 370472
This relands this commit, I mistakenly reverted the original change
thinking it was the cause of the observed MSan failures but it was not.
llvm-svn: 370206
This is a follow up discussed in the comments of D66583.
Currently, if for example, we have both StOther and Other set in YAML document for a symbol,
then yaml2obj reports an "unknown key 'Other'" error.
It happens because 'mapOptional()' is never called for 'Other/Visibility' in this case,
leaving those unhandled.
This message does not describe the reason of the error well. This patch fixes it.
Differential revision: https://reviews.llvm.org/D66642
llvm-svn: 370032
st_other field of a symbol usually contains its visibility.
Other bits are usually 0, though some targets, like
MIPS can set them using the named bit field values.
Problem is that there is no way to set an arbitrary value now,
though that might be useful for our test cases.
In this patch I introduced a way to set st_other to any numeric
value using the new StOther field.
I added a test and simplified the existent one to show the effect/benefit
Differential revision: https://reviews.llvm.org/D66583
llvm-svn: 369742
In some cases a symbol might have section index == SHN_XINDEX.
This is an escape value indicating that the actual section header index
is too large to fit in the containing field.
Then the SHT_SYMTAB_SHNDX section is used. It contains the 32bit values
that stores section indexes.
ELF gABI says that there can be multiple SHT_SYMTAB_SHNDX sections,
i.e. for example one for .symtab and one for .dynsym
(1) https://groups.google.com/forum/#!topic/generic-abi/-XJAV5d8PRg
(2) DT_SYMTAB_SHNDX: http://www.sco.com/developers/gabi/latest/ch5.dynamic.html
In this patch I am only supporting a single SHT_SYMTAB_SHNDX associated
with a .symtab. This is a more or less common case which is used a few tests I saw in LLVM.
I decided not to create the SHT_SYMTAB_SHNDX section as "implicit",
but implement is like a kind of regular section for now.
i.e. tools do not recreate this section or its content, like they do for
symbol table sections, for example. That should allow to write all kind of
possible broken test cases for our needs and keep the output closer to requested.
Differential revision: https://reviews.llvm.org/D65446
llvm-svn: 368272
There is no way to set broken sh_size field currently
for sections. It can be usefull for writing the
test cases.
Differential revision: https://reviews.llvm.org/D64401
llvm-svn: 365766
Some of our test cases are using objects which
has sections with a broken sh_offset field.
There was no way to set it from YAML until this patch.
Differential revision: https://reviews.llvm.org/D63879
llvm-svn: 364898
This allows setting different values for e_shentsize, e_shoff, e_shnum
and e_shstrndx fields and is useful for producing broken inputs for various
test cases.
Differential revision: https://reviews.llvm.org/D63771
llvm-svn: 364517
Summary:
The directive defines a symbol as an group/local memory (LDS) symbol.
LDS symbols behave similar to common symbols for the purposes of ELF,
using the processor-specific SHN_AMDGPU_LDS as section index.
It is the linker and/or runtime loader's job to "instantiate" LDS symbols
and resolve relocations that reference them.
It is not possible to initialize LDS memory (not even zero-initialize
as for .bss).
We want to be able to link together objects -- starting with relocatable
objects, but possible expanding to shared objects in the future -- that
access LDS memory in a flexible way.
LDS memory is in an address space that is entirely separate from the
address space that contains the program image (code and normal data),
so having program segments for it doesn't really make sense.
Furthermore, we want to be able to compile multiple kernels in a
compilation unit which have disjoint use of LDS memory. In that case,
we may want to place LDS symbols differently for different kernels
to save memory (LDS memory is very limited and physically private to
each kernel invocation), so we can't simply place LDS symbols in a
.lds section.
Hence this solution where LDS symbols always stay undefined.
Change-Id: I08cbc37a7c0c32f53f7b6123aa0afc91dbc1748f
Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, rupprecht, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61493
llvm-svn: 364296
With this patch we get ability to set any flags we want
for implicit sections defined in YAML.
Differential revision: https://reviews.llvm.org/D63136
llvm-svn: 363367
This is a follow-up for D62809.
Content and Size fields should be optional as was discussed in comments
of the D62809's thread. With that, we can describe a specific string table and
symbol table sections in a more correct way and also show appropriate errors.
The patch adds lots of test cases where the behavior is described in details.
Differential revision: https://reviews.llvm.org/D62957
llvm-svn: 362931
In glibc, DT_PPC_GOT indicates that PowerPC32 Secure PLT ABI is used.
I plan to use it in D62464.
DT_PPC_OPT currently indicates if a TLSDESC inspired TLS optimization is
enabled.
Reviewed By: grimar, jhenderson, rupprecht
Differential Revision: https://reviews.llvm.org/D62851
llvm-svn: 362569
ELF for the 64-bit Arm Architecture defines two processor-specific dynamic
tags:
DT_AARCH64_BTI_PLT 0x70000001, d_val
DT_AARCH64_PAC_PLT 0x70000003, d_val
These presence of these tags indicate that PLT sequences have been
protected using Branch Target Identification and Pointer Authentication
respectively. The presence of both indicates that the PLT sequences have
been protected with both Branch Target Identification and Pointer
Authentication.
This patch adds the tags and tests for llvm-readobj and yaml2obj.
As some of the processor specific dynamic tags overlap, this patch splits
them up, keeping their original default value if they were not previously
mentioned explicitly in a switch case.
Differential Revision: https://reviews.llvm.org/D62596
llvm-svn: 362493
This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.
Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.
The design goals were to provide:
- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
environments (MSVC in particular).
Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.
In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:
1. There are no competing defined symbols in a given set of libraries, or
if they exist, the program owner doesn't care which is linked to their
program.
2. There may be circular dependencies between libraries.
The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:
.section ".deplibs","MS",@llvm_dependent_libraries,1
.asciz "foo"
For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.
LLD processes the dependent library specifiers in the following way:
1. Dependent libraries which are found from the specifiers in .deplibs sections
of relocatable object files are added when the linker decides to include that
file (which could itself be in a library) in the link. Dependent libraries
behave as if they were appended to the command line after all other options. As
a consequence the set of dependent libraries are searched last to resolve
symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
strings in a .deplibs section by; first, handling the string as if it was
specified on the command line; second, by looking for the string in each of the
library search paths in turn; third, by looking for a lib<string>.a or
lib<string>.so (depending on the current mode of the linker) in each of the
library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
dependent libraries.
Rationale for the above points:
1. Adding the dependent libraries last makes the process simple to understand
from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
will affect all of the dependent libraries. There is a potential problem of
surprise for developers, who might not realize that these options would apply
to these "invisible" input files; however, despite the potential for surprise,
this is easy for developers to reason about and gives developers the control
that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
find input files. The different search methods are tried by the linker in most
obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
is not necessary: if finer control is required developers can fall back to using
the command line directly.
RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.
Differential Revision: https://reviews.llvm.org/D60274
llvm-svn: 360984
In some cases it is useful to explicitly set symbol's st_name value.
For example, I am using it in a patch for LLD to remove the broken
binary from a test case and replace it with a YAML test.
Differential revision: https://reviews.llvm.org/D61180
llvm-svn: 360137
Currently, YAML has the following syntax for describing the symbols:
Symbols:
Local:
LocalSymbol1:
...
LocalSymbol2:
...
...
Global:
GlobalSymbol1:
...
Weak:
...
GNUUnique:
I.e. symbols are grouped by their bindings. That is not very convenient,
because:
It does not allow to set a custom binding, what can be useful for producing
broken/special outputs for test cases. Adding a new binding would require to
change a syntax (what we observed when added GNUUnique recently).
It does not allow to change the order of the symbols in .symtab/.dynsym,
i.e. currently all Local symbols are placed first, then Global, Weak and GNUUnique
are following, but we are not able to change the order.
It is not consistent. Binding is just one of the properties of the symbol,
we do not group them by other properties.
It makes the code more complex that it can be. This patch shows it can be simplified
with the change performed.
The patch changes the syntax to just:
Symbols:
Symbol1:
...
Symbol2:
...
...
With that, we are able to work with the binding field just like with any other symbol property.
Differential revision: https://reviews.llvm.org/D60122
llvm-svn: 357595
yaml2obj currently derives the p_filesz, p_memsz, and p_offset values of
program headers from their sections. This makes writing tests for
certain formats more complex, and sometimes impossible. This patch
allows setting these fields explicitly, overriding the default value,
when relevant.
Reviewed by: jakehehrlich, Higuoxing
Differential Revision: https://reviews.llvm.org/D59372
llvm-svn: 356247
I need this to remove a binary from LLD test suite.
The patch also simplifies the code a bit.
Differential revision: https://reviews.llvm.org/D59082
llvm-svn: 355591
This is for tweaking SHT_SYMTAB sections.
Their sh_info contains the (number of symbols + 1) usually.
But for creating invalid inputs for test cases it would be convenient
to allow explicitly override this field from YAML.
Differential revision: https://reviews.llvm.org/D58779
llvm-svn: 355193
This allows tools to parse/dump the architecture specific tags
like DT_MIPS_*, DT_PPC64_* and DT_HEXAGON_*
Also fixes a bug in DynamicTags.def which was revealed in this patch.
Differential revision: https://reviews.llvm.org/D58667
llvm-svn: 354876
Recently, support was added to yaml2obj to allow dynamic sections to
have a list of entries, to make it easier to write tests with dynamic
sections. However, this change also removed the ability to provide
custom contents to the dynamic section, making it hard to test
malformed contents (e.g. because the section is not a valid size to
contain an array of entries). This change reinstates this. An error is
emitted if raw content and dynamic entries are both specified.
Reviewed by: grimar, ruiu
Differential Review: https://reviews.llvm.org/D58543
llvm-svn: 354770
In order to test tool handling of invalid section indexes, I need to
create an object containing such an invalid section index. I could
create a hex-edited binary, but having the ability to use yaml2obj is
preferable. Prior to this change, yaml2obj would reject any explicit
section indexes less than SHN_LORESERVE. This patch changes it to allow
any value.
I had to change the test to use llvm-readelf instead of llvm-readobj,
because llvm-readobj does not like invalid section indexes. I've also
expanded the test to show that the most common SHN_* values are accepted
(SHN_UNDEF, SHN_ABS, SHN_COMMON).
Reviewed by: grimar, jakehehrlich
Differential Revision: https://reviews.llvm.org/D58445
llvm-svn: 354566
yaml2obj/obj2yaml previously supported SHT_LOOS, SHT_HIOS, and
SHT_LOPROC for section types. These are simply values that delineate a
range and don't really make sense as valid values. For example if a
section has type value 0x70000000, obj2yaml shouldn't print this value
as SHT_LOPROC. Additionally, this was missing the three other range
markers (SHT_HIPROC, SHT_LOUSER and SHT_HIUSER).
This change removes these three range markers. It also adds support for
specifying the type as an integer, to allow section types that LLVM
doesn't know about.
Reviewed by: grimar
Differential Revision: https://reviews.llvm.org/D58383
llvm-svn: 354344
Fix:
Replace
assert(!IO.getContext() && "The IO context is initialized already");
with
assert(IO.getContext() && "The IO context is not initialized");
(this was introduced in r354329, where I tried to quickfix the darwin BB
and seems copypasted the assert from the wrong place).
Original commit message:
The section is described here:
https://refspecs.linuxfoundation.org/LSB_1.3.0/gLSB/gLSB/symverrqmts.html
Patch just teaches obj2yaml/yaml2obj to dump and parse such sections.
We did the finalization of string tables very late,
and I had to move the logic to make it a bit earlier.
That was needed in this patch since .gnu.version_r adds strings to .dynstr.
This might also be useful for implementing other special sections.
Everything else changed in this patch seems to be straightforward.
Differential revision: https://reviews.llvm.org/D58119
llvm-svn: 354335
The section is described here:
https://refspecs.linuxfoundation.org/LSB_1.3.0/gLSB/gLSB/symverrqmts.html
Patch just teaches obj2yaml/yaml2obj to dump and parse such sections.
We did the finalization of string tables very late,
and I had to move the logic to make it a bit earlier.
That was needed in this patch since .gnu.version_r adds strings to .dynstr.
This might also be useful for implementing other special sections.
Everything else changed in this patch seems to be straightforward.
Differential revision: https://reviews.llvm.org/D58119
llvm-svn: 354328
ELFYAML.h contains a `Section` class which is a base for a few other
sections classes that are used for mapping different section types.
`Section` has a `StringRef Info` field used for storing sh_info.
At the same time, sh_info has very different meanings for sections and
cannot be processed in a similar way generally,
for example ELFDumper does not handle it in `dumpCommonSection`
but do that in `dumpGroup` and `dumpCommonRelocationSection` respectively.
At this moment, we have and handle it as a string, because that was possible for
the current use case. But also it can simply be a number:
For SHT_GNU_verdef is "The number of version definitions within the section."
The patch moves `Info` field out to be able to have it as a number.
With that change, each class will be able to decide what type and purpose
of the sh_info field it wants to use.
I also had to edit 2 test cases. This is because patch fixes a bug. Previously we
accepted yaml files with Info fields for all sections (for example, for SHT_DYNSYM too).
But we do not handle it and the resulting objects had zero sh_info fields set for
such sections. Now it is accepted only for sections that supports it.
Differential revision: https://reviews.llvm.org/D58054
llvm-svn: 353810
The second and the last place it seems.
Error was:
[ 4%] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/Error.cpp.o
/Users/buildslave/as-bldslv9_new/lld-x86_64-darwin13/llvm.src/lib/ObjectYAML/ELFYAML.cpp:993:15: error: unused variable 'Object' [-Werror,-Wunused-variable]
const auto *Object = static_cast<ELFYAML::Object *>(IO.getContext());
llvm-svn: 353609
This teaches the tools to parse and dump
the .dynamic section and its dynamic tags.
Differential revision: https://reviews.llvm.org/D57691
llvm-svn: 353606
yaml2obj previously only recognised standard STT_* names, and didn't
allow arbitrary numbers. This change allows the user to specify a number
for the type instead. It also adds a test to verify the existing
behaviour for obj2yaml for unkown symbol types.
Reviewed by: grimar
Differential Revision: https://reviews.llvm.org/D57822
llvm-svn: 353315
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
These tools were assuming ABI version is 0,
that is not always true.
Patch teaches them to work with that field.
Differential revision: https://reviews.llvm.org/D55884
llvm-svn: 349737
Fangrui Song