Summary:
WebAssembly memories are zero-initialized, so when module does not
import its memory initializing .bss sections is guaranteed to be a
no-op. To reduce binary size and initialization time, .bss sections
are simply not emitted into the final binary unless the memory is
imported.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68965
llvm-svn: 374940
This patch does the same thing as r365595 to other subdirectories,
which completes the naming style change for the entire lld directory.
With this, the naming style conversion is complete for lld.
Differential Revision: https://reviews.llvm.org/D64473
llvm-svn: 365730
Summary:
Adds `--passive-segments` and `--active-segments` flags to control
what kind of segments are emitted. For now the default is always
to emit active segments so this is not a breaking change, but in
the future the default will be changed to passive segments when
shared memory is requested and active segments otherwise. When
passive segments are emitted, corresponding memory.init and
data.drop instructions are emitted in a `__wasm_init_memory`
function that is automatically called at the beginning of
`__wasm_call_ctors`.
Reviewers: sbc100, aheejin, dschuff
Subscribers: azakai, dschuff, jgravelle-google, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59343
llvm-svn: 365088
Summary:
Make `wasm-ld --verbose` show data section start virtual address and name
as well, instead of just showing the size. This makes it much easier to
track which global variable is in which address when used in conjunction
with `--no-merge-data-sections`.
Patch by Guanzhong Chen
Reviewers: tlively, aheejin, sbc100, ruiu
Reviewed By: sbc100, ruiu
Subscribers: ruiu, dschuff, jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62834
llvm-svn: 362548
Major refactor to better match the structure of the ELF linker.
- Split out relocation processing into scanRelocations
- Split out synthetic sections into their own classes.
Differential Revision: https://reviews.llvm.org/D61811
llvm-svn: 361233
Previously these sections were being generated during their
constructors. This moves the work to finalizeContent, and also does
the same for the relocation sections because their contents depends
on the final layout too.
This change is part of a larger refactor to how we deal with synthetic
sections: https://reviews.llvm.org/D61811
Differential Revision: https://reviews.llvm.org/D61971
llvm-svn: 360941
Summary:
The DataCount section is necessary for the bulk memory operations
memory.init and data.drop to validate, but it is not recognized by
engines that do not support bulk memory, so emit the section only if
bulk-memory is enabled.
Reviewers: aheejin, dschuff, sbc100
Subscribers: jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60637
llvm-svn: 358798
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
This change adds the ability for lld to remove LEB padding from
code section. This effectively shrinks the size of the resulting
binary in proportion to the number of code relocations.
Since there will be a performance cost this is currently only active for
-O1 and above. Some toolchains may instead want to perform this
compression as a post linker step (for example running a binary through
binaryen will automatically compress these values).
I imagine we might want to make this the default in the future.
Differential Revision: https://reviews.llvm.org/D46416
llvm-svn: 332783
Specifically add support for custom sections that contain
relocations, and for the two new relocation types needed
by DWARF sections.
See: https://reviews.llvm.org/D44184
Patch by Yury Delendik!
Differential Revision: https://reviews.llvm.org/D44184
llvm-svn: 331566
Copy user-defined custom sections into the output, concatenating
sections with the same name.
Differential Revision: https://reviews.llvm.org/D45340
llvm-svn: 329717
SubSection inherited from SyntheticSection, and SyntheticSection inherits
from OutputSection, so SubSection was an OutputSection. But that's wrong
because SubSection is not actually a WebAssembly output section.
It shares some functionalities with OutputSection, but overall it's very
different.
This patch removes that inheritance.
Differential Revision: https://reviews.llvm.org/D43719
llvm-svn: 326286
The profailing style in lld seem to be to not include such empty lines.
Clang-tidy/clang-format seem to handle this just fine.
Differential Revision: https://reviews.llvm.org/D43528
llvm-svn: 325629
This patch removes `OutRelocations` vector from the InputChunk and
directly consume `Relocations` vector instead. This should make the linker
faster because we don't create a temporary data structure, and it matches
the lld's design principle that we don't create temporary data structures
for object files but instead directly consume mmap'ed data whenever possible.
Differential Revision: https://reviews.llvm.org/D43491
llvm-svn: 325549
Summary:
- Makes code more in line with LLVM style (e.g. const char * -> StringRef)
- Do not use formatv since we can construct message just by `+`
- Replace some odd types such as `const StringRef` with more common type
- Do not use default arguments if they are not necessary
Reviewers: sbc100
Subscribers: jfb, aheejin, llvm-commits, sunfish
Differential Revision: https://reviews.llvm.org/D43403
llvm-svn: 325383
The code section is now written out one function
at a time rather than all the functions in a given
objects being serialized at once.
This change lays the groundwork for supporting
--gc-sections.
Differential Revision: https://reviews.llvm.org/D41315
llvm-svn: 322138
The addresses of undefined symbols that make it into the final
executable (i.e. weak references to non-existent symbols) should
resolve to zero.
Also, make sure to not include function in the indirect function
table if they are not included in the output.
Differential Revision: https://reviews.llvm.org/D41839
llvm-svn: 322045
Store data relocations with their respective segment.
This allows relocations to be applied as each segment
is written (and therefore in parallel).
Differential Revision: https://reviews.llvm.org/D41410
llvm-svn: 321105
This change add support for init functions in the linking
section, but only in -r/--relocatable mode.
Differential Revision: https://reviews.llvm.org/D41375
llvm-svn: 321088
This change cleans up the way wasm exports and globals
are generated, particualrly for -r/--relocatable where
globals need to be created and exported in order for
output relocations which reference them.
Remove the need for a per file GlobalIndexOffset and
instead set the output index for each symbol directly.
This simplifies the code in several places.
Differential Revision: https://reviews.llvm.org/D40859
llvm-svn: 320001
This linker backend is still a work in progress but is
enough to link simple programs including linking against
library archives.
Differential Revision: https://reviews.llvm.org/D34851
llvm-svn: 318539
Thomas Lively