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
I was trying to add a test case for LLD and found that it
is impossible to set sh_entsize via yaml.
The patch implements the missing part.
Differential revision: https://reviews.llvm.org/D50235
llvm-svn: 339113
This change adds experimental support for SHT_RELR sections, proposed
here: https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
Definitions for the new ELF section type and dynamic array tags, as well
as the encoding used in the new section are all under discussion and are
subject to change. Use with caution!
Author: rahulchaudhry
Differential Revision: https://reviews.llvm.org/D47919
llvm-svn: 335922
Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:
.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20
When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).
Differential Revision: https://reviews.llvm.org/D44965
llvm-svn: 333823
Summary:
Original change was D43313 (r326932) and reverted by r326953 because it
broke an LLD test and a windows build. The LLD test was already fixed in
lld commit r326944 (thanks maskray). This is the original change with
the windows build fixed.
llvm-svn: 326970
This patch enhances DWARFDebugFrame with the capability of parsing and
printing DWARF expressions in CFI instructions. It also makes FDEs and
CIEs accessible to lib users, so they can process them in client tools
that rely on LLVM. To make it self-contained with a test case, it
teaches llvm-readobj to be able to dump EH frames and checks they are
correct in a unit test. The llvm-readobj code is Maksim Panchenko's work
(maksfb).
Reviewers: JDevlieghere, espindola
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D43313
llvm-svn: 326932
Introduce an extension to support passing linker options to the linker.
These would be ignored by older linkers, but newer linkers which support
this feature would be able to process the linker.
Emit a special discarded section `.linker-option`. The content of this
section is a pair of strings (key, value). The key is a type identifier for
the parameter. This allows for an argument free parameter that will be
processed by the linker with the value being the parameter. As an example,
`lib` identifies a library to be linked against, traditionally the `-l`
argument for Unix-based linkers with the parameter being the library name.
Thanks to James Henderson, Cary Coutant, Rafael Espinolda, Sean Silva
for the valuable discussion on the design of this feature.
llvm-svn: 323783
Summary:
This change introduces a `DynamicSymbols` field to the ELF specific YAML
supported by `yaml2obj` and `obj2yaml`. This grouping of symbols provides a way
to represent ELF dynamic symbols. The `DynamicSymbols` structure is identical to
the existing `Symbols`.
Reviewers: compnerd, jakehehrlich, silvas
Reviewed By: silvas
Subscribers: silvas, jakehehrlich, llvm-commits
Differential Revision: https://reviews.llvm.org/D39582
llvm-svn: 318433
Summary:
This change allows yaml input to control the order of implicitly added sections
(`.symtab`, `.strtab`, `.shstrtab`). The order is controlled by adding a
placeholder section of the given name to the Sections field.
This change is to support changes in D39582, where it is desirable to control
the location of the `.dynsym` section.
This reapplied version fixes:
1. use of a function call within an assert
2. failing lld test which has an unnamed section
3. incorrect section count when given an unnamed section
Additionally, one more test to cover the unnamed section failure.
Reviewers: compnerd, jakehehrlich
Reviewed By: jakehehrlich
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39749
llvm-svn: 317789
Summary:
This change allows yaml input to control the order of implicitly added sections
(`.symtab`, `.strtab`, `.shstrtab`). The order is controlled by adding a
placeholder section of the given name to the Sections field.
This change is to support changes in D39582, where it is desirable to control
the location of the `.dynsym` section.
This reapplied version fixes:
1. use of a function call within an assert
2. failing lld test which has an unnamed section
Additionally, one more test to cover the unnamed section failure.
Reviewers: compnerd, jakehehrlich
Reviewed By: jakehehrlich
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39749
llvm-svn: 317646
Summary:
This change allows yaml input to control the order of implicitly added sections
(`.symtab`, `.strtab`, `.shstrtab`). The order is controlled by adding a
placeholder section of the given name to the Sections field.
This change is to support changes in D39582, where it is desirable to control
the location of the `.dynsym` section.
Reviewers: compnerd, jakehehrlich
Reviewed By: jakehehrlich
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39749
llvm-svn: 317622
Sometimes program headers have larger alignments than any of the
sections they contain. Currently yaml2obj can't produce such files. A
bug recently appeared in llvm-objcopy that failed in such a case. I'd
like to be able to add tests to llvm-objcopy for such cases.
This change adds an optional alignment parameter to program headers that
will be used instead of calculating the alignment.
Differential Revision: https://reviews.llvm.org/D39130
llvm-svn: 317139
This is in preparation for testing lld's upcoming relocation packing
feature (D39152). I have verified that this implementation correctly
unpacks the relocations from a Chromium DSO built with gold and the
Android relocation packer for ARM32 and ARM64.
Differential Revision: https://reviews.llvm.org/D39272
llvm-svn: 316543
This was previously being silently dropped by obj2yaml and caused
parsing errors with yaml2obj.
Differential Revision: https://reviews.llvm.org/D38490
llvm-svn: 314768
Right now Symbols must be either undefined or defined in a specific
section. Some symbols have section indexes like SHN_ABS however. This
change adds support for outputting symbols that have such section
indexes.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D37391
llvm-svn: 312745
Some kinds of relocations do not have symbols, like R_X86_64_RELATIVE
for instance. I would like to test this case in D36554 but currently
can't because symbols are required by yaml2obj. The other option is
using the empty symbol but that doesn't seem quite right to me.
This change makes the Symbol field of Relocation optional and in the
case where the user does not specify a symbol name the Symbol index is 0.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D37276
llvm-svn: 312192
This change adds basic support for program headers.
I need to do some testing which requires generating program headers but
I can't use ld.lld or clang to produce programs that have headers. I'd
also like to test some strange things that those programs may never
produce.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D35276
llvm-svn: 308520
That may be useful if we want to produce or parse object containing
broken relocation values using yaml2obj/obj2yaml.
Previously that was impossible because only enum values were parsed
correctly, this patch allows to put any numeric value as a
relocation type.
Differential revision: https://reviews.llvm.org/D34758
llvm-svn: 306814
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
This implements execute-only support for ARM code generation, which
prevents the compiler from generating data accesses to code sections.
The following changes are involved:
* Add the CodeGen option "-arm-execute-only" to the ARM code generator.
* Add the clang flag "-mexecute-only" as well as the GCC-compatible
alias "-mpure-code" to enable this option.
* When enabled, literal pools are replaced with MOVW/MOVT instructions,
with VMOV used in addition for floating-point literals. As the MOVT
instruction is required, execute-only support is only available in
Thumb mode for targets supporting ARMv8-M baseline or Thumb2.
* Jump tables are placed in data sections when in execute-only mode.
* The execute-only text section is assigned section ID 0, and is
marked as unreadable with the SHF_ARM_PURECODE flag with symbol 'y'.
This also overrides selection of ELF sections for globals.
llvm-svn: 289784
Add the necessary definitions for RISC-V ELF files, including relocs. Also
make necessary trivial change to ELFYaml, llvm-objdump, and llvm-readobj in
order to work with RISC-V ELFs.
Differential Revision: https://reviews.llvm.org/D23557
llvm-svn: 285708
The same value for EM_BPF is being propagated to glibc,
elfutils, and binutils.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 275633
Summary:
Our YAML library's handling of tags isn't perfect, but it is good enough to get rid of the need for the --format argument to yaml2obj. This patch does exactly that.
Instead of requiring --format, it infers the format based on the tags found in the object file. The supported tags are:
!ELF
!COFF
!mach-o
!fat-mach-o
I have a corresponding patch that is quite large that fixes up all the in-tree test cases.
Reviewers: rafael, Bigcheese, compnerd, silvas
Subscribers: compnerd, llvm-commits
Differential Revision: http://reviews.llvm.org/D21711
llvm-svn: 273915
George Rimar