I can't access my Windows machine at the moment, but the build was breaking with:
c:\b\build\slave\crwinclanglld\build\src\third_party\llvm\tools\lld\lib\readerwriter\elf\mips\MipsTargetLayout.h(38) : error C2440: 'return' : cannot convert from 'lld:🧝:MipsGOTSection<ELFT> *' to 'lld:🧝:AtomSection<ELFT> *'
with
[
ELFT=lld:🧝:Mips32ELType
]
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
I think this regressed caused in 234727: that the forward-declarations
of MipsGOTSection<> is not enough.
llvm-svn: 234736
When we call getGP() we need in fact _gp symbol address. Let's cache its
value and return it directly from the new getGPAddr() function.
llvm-svn: 234632
In case of MIPS N64 ABI linker should merge registers usage masks stored
in the input .MIPS.options sections and save result into the output
.MIPS.options section.
llvm-svn: 234115
In case of MIPS O32 ABI linker should merge registers usage masks stored
in the input .reginfo sections and save result into the output .reginfo
section.
The ABI states that the .reginfo section should be put into the separate
segment. This requirement is not implemented in this patch.
llvm-svn: 234103
N64 ABI relocation record r_info field in fact consists of five subfields:
* r_sym - symbol index
* r_ssym - special symbol
* r_type3 - third relocation type
* r_type2 - second relocation type
* r_type - first relocation type
Up to three these relocations applied one by one. The first relocation
uses an addendum from the relocation record. Each subsequent relocation
takes as its addend the result of the previous operation. Only the final
operation actually modifies the location relocated. The first relocation
uses as a reference symbol specified by the `r_sym` field. The third
relocation assumes NULL symbol.
The patch represents these data using LLD model and takes in account
additional relocation types during a relocation calculation.
Additional relocations do not introduce any new relations between two
atoms and just specify operations need to be done during a relocation
calculation. The first relocation type (`r_type`) stored in the
`Reference::_kindValue`. The rest of relocations and `r_ssym` value are
stored in the new `Reference::_tag` field "as-is". I decided to do not
"decode" these data on the core LLD level to prevent pollution of the
core LLD model by very target specific data.
Also I have to override writing of relocation records in the `RelocationTable`
class to convert MIPS N64 ABI relocation information from the `Reference`
class back to the ELF relocation record.
http://reviews.llvm.org/D8533
llvm-svn: 233057
SHF_GROUP: Group Member Sections
----------------------------------
A section which is part of a group, and is to be retained or discarded with the
group as a whole, is identified by a new section header attribute: SHF_GROUP
This section is a member (perhaps the only one) of a group of sections, and the
linker should retain or discard all or none of the members. This section must be
referenced in a SHT_GROUP section. This attribute flag may be set in any section
header, and no other modification or indication is made in the grouped sections.
All additional information is contained in the associated SHT_GROUP section.
SHT_GROUP: Section Group Definition
-------------------------------------
Represents a group section.
The section group's sh_link field identifies a symbol table section, and its
sh_info field the index of a symbol in that section. The name of that symbol is
treated as the identifier of the section group.
More information: https://mentorembedded.github.io/cxx-abi/abi/prop-72-comdat.html
Added a lot of extensive tests, that tests functionality.
llvm-svn: 230195
1. Re-implement PLT entries and dynamic relocations emitting to keep PLT
and relocations table in a consistent state.
2. Initialize st_value and st_other fields for dynamic symbols table
entry if this entry corresponds to an external function which address is
taken in a non-PIC executable. In that case the st_value field holds an
address of the function's PLT entry. Also set STO_MIPS_PLT bit in the
st_other field.
llvm-svn: 207494
The main changes are in:
include/lld/Core/Reference.h
include/lld/ReaderWriter/Reader.h
Everything else is details to support the main change.
1) Registration based Readers
Previously, lld had a tangled interdependency with all the Readers. It would
have been impossible to make a streamlined linker (say for a JIT) which
just supported one file format and one architecture (no yaml, no archives, etc).
The old model also required a LinkingContext to read an object file, which
would have made .o inspection tools awkward.
The new model is that there is a global Registry object. You programmatically
register the Readers you want with the registry object. Whenever you need to
read/parse a file, you ask the registry to do it, and the registry tries each
registered reader.
For ease of use with the existing lld code base, there is one Registry
object inside the LinkingContext object.
2) Changing kind value to be a tuple
Beside Readers, the registry also keeps track of the mapping for Reference
Kind values to and from strings. Along with that, this patch also fixes
an ambiguity with the previous Reference::Kind values. The problem was that
we wanted to reuse existing relocation type values as Reference::Kind values.
But then how can the YAML write know how to convert a value to a string? The
fix is to change the 32-bit Reference::Kind into a tuple with an 8-bit namespace
(e.g. ELF, COFFF, etc), an 8-bit architecture (e.g. x86_64, PowerPC, etc), and
a 16-bit value. This tuple system allows conversion to and from strings with
no ambiguities.
llvm-svn: 197727
The following are the most significant peculiarities of MIPS target:
- MIPS ABI requires some special tags in the dynamic table.
- GOT consists of two parts local and global. The local part contains
entries refer locally visible symbols. The global part contains entries
refer global symbols.
- Entries in the .dynsym section which have corresponded entries in the
GOT should be:
* Emitted at the end of .dynsym section
* Sorted accordingly to theirs GOT counterparts
- There are "paired" relocations. One or more R_MIPS_HI16 and R_MIPS_GOT16
relocations should be followed by R_MIPS_LO16 relocation. To calculate
result of R_MIPS_HI16 and R_MIPS_GOT16 relocations we need to combine
addends from these relocations and paired R_MIPS_LO16 relocation.
The patch reviewed by Michael Spencer, Shankar Easwaran, Rui Ueyama.
http://llvm-reviews.chandlerc.com/D2156
llvm-svn: 197342
Simon Atanasyan