https://reviews.llvm.org/D47381 / eb46c95c3e
changed the triples set up by GetHostTriple.cmake for i686 MSVC
from i686-pc-win32 to i686-pc-windows-msvc without changing
the corresponding condition in llvm-shlib.
Since then, the 32 bit x86 build of LLVM-C.dll has contained no
exported symbols at all.
Differential Revision: https://reviews.llvm.org/D109493
This is an ELF specific option which isn't supported for Windows/MinGW
targets, even if the MinGW linker otherwise uses an ld.bfd like linker
interface.
Differential Revision: https://reviews.llvm.org/D105148
llvm-dev message: https://lists.llvm.org/pipermail/llvm-dev/2021-May/150465.html
In an ELF shared object, a default visibility defined symbol is preemptible by
default. This creates some missed optimization opportunities.
-Bsymbolic-functions is more aggressive than our current -fvisibility-inlines-hidden
(present since 2012) as it applies to all function definitions. It can
* avoid PLT for cross-TU function calls && reduce dynamic symbol lookup
* reduce dynamic symbol lookup for taking function addresses and optimize out GOT/TOC on x86-64/ppc64
In a -DLLVM_TARGETS_TO_BUILD=X86 build, the number of JUMP_SLOT decreases from 12716 to 1628, and the number of GLOB_DAT decreases from 1918 to 1313
The built clang with `-DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on` is significantly faster.
See the Linux kernel build result https://bugs.archlinux.org/task/70697
Note: the performance of -fno-semantic-interposition -Bsymbolic-functions
libLLVM.so and libclang-cpp.so is close to a PIE binary linking against
`libLLVM*.a` and `libclang*.a`. When the host compiler is Clang,
-Bsymbolic-functions is the major contributor. On x86-64 (with GOTPCRELX) and
ppc64 ELFv2, the GOT/TOC relocations can be optimized.
Some implication:
Interposing a subset of functions is no longer supported.
(This is fragile on ELF and unsupported on Mach-O at all. For Mach-O we don't
use `ld -interpose` or `-flat_namespace`)
Compiling a program which takes the address of any LLVM function with
`{gcc,clang} -fno-pic` and expects the address to equal to the address taken
from libLLVM.so or libclang-cpp.so is unsupported. I am fairly confident that
llvm-project shouldn't have different behaviors depending on such pointer
equality (as we've been using -fvisibility-inlines-hidden which applies to
inline functions for a long time), but if we accidentally do, users should be
aware that they should not make assumption on pointer equality in `-fno-pic`
mode.
See more on https://maskray.me/blog/2021-05-09-fno-semantic-interposition
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D102090
llvm-dev message: https://lists.llvm.org/pipermail/llvm-dev/2021-May/150465.html
In an ELF shared object, a default visibility defined symbol is preemptible by default.
This creates some missed optimization opportunities. -fno-semantic-interposition can optimize -fPIC:
* in Clang: avoid GOT/PLT cost for variable access/function calls to external linkage definition in the same TU
* in GCC: enable interprocedural optimizations (including inlining) and avoid PLT
See https://gist.github.com/MaskRay/2d4dfcfc897341163f734afb59f689c6 for more information.
-Bsymbolic-functions is more aggressive than -fvisibility-inlines-hidden (present since 2012) as it applies
to all function definitions. It can
* avoid PLT for cross-TU function calls && reduce dynamic symbol lookup
* reduce dynamic symbol lookup for taking function addresses and optimize out GOT/TOC on x86-64/ppc64
With both options, the libLLVM.so and libclang-cpp.so performance should
be closer to PIE binary linking against `libLLVM*.a` and `libclang*.a`
(In a -DLLVM_TARGETS_TO_BUILD=X86 build, the number of JUMP_SLOT decreases from 12716 to 1628, and the number of GLOB_DAT decreases from 1918 to 1313
The built clang with `-DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on` is significantly faster.
See the Linux kernel build result https://bugs.archlinux.org/task/70697
)
Some implication:
Interposing a subset of functions is no longer supported.
(This is fragile anyway and cannot really be supported. For Mach-O we don't use
`ld -interpose`, so interposition is not supported on Mach-O at all.)
Compiling a program which takes the address of any LLVM function with
`{gcc,clang} -fno-pic` and expects the address to equal to the address taken
from libLLVM.so or libclang-cpp.so is unsupported. I am fairly confident that
llvm-project shouldn't have different behaviors depending on such pointer
equality (as we've been using -fvisibility-inlines-hidden which applies to
inline functions for a long time), but if we accidentally do, users should be
aware that they should not make assumption on pointer equality in `-fno-pic`
mode.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D102090
This makes it possible to build libLLVM.so without first creating a
static library for each component. In the case where only libLLVM.so is
built (i.e. ninja LLVM) this eliminates 150 linker jobs.
Reviewed By: stellaraccident
Differential Revision: https://reviews.llvm.org/D95727
This patch optionally replaces the CRT allocator (i.e., malloc and free) with rpmalloc (mixed public domain licence/MIT licence) or snmalloc (MIT licence) or mimalloc (MIT licence). Please note that the source code for these allocators must be available outside of LLVM's tree.
To enable, use `cmake ... -DLLVM_INTEGRATED_CRT_ALLOC=D:/git/rpmalloc -DLLVM_USE_CRT_RELEASE=MT` where `D:/git/rpmalloc` has already been git clone'd from `https://github.com/mjansson/rpmalloc`. The same applies to snmalloc and mimalloc.
When enabled, the allocator will be embeded (statically linked) into the LLVM tools & libraries. This currently only works with the static CRT (/MT), although using the dynamic CRT (/MD) could potentially work as well in the future.
When enabled, this changes the memory stack from:
new/delete -> MS VC++ CRT malloc/free -> HeapAlloc -> VirtualAlloc
to:
new/delete -> {rpmalloc|snmalloc|mimalloc} -> VirtualAlloc
The goal of this patch is to bypass the application's global heap - which is thread-safe thus inducing locking - and instead take advantage of a modern lock-free, thread cache, allocator. On a 6-core Xeon Skylake we observe a 2.5x decrease in execution time when linking a large scale application with LLD and ThinLTO (12 min 20 sec -> 5 min 34 sec), when all hardware threads are being used (using LLD's flag /opt:lldltojobs=all). On a dual 36-core Xeon Skylake with all hardware threads used, we observe a 24x decrease in execution time (1 h 2 min -> 2 min 38 sec) when linking a large application with LLD and ThinLTO. Clang build times also see a decrease in the range 5-10% depending on the configuration.
Differential Revision: https://reviews.llvm.org/D71786
The new option works like the existing LLVM_TABLEGEN, and
LLVM_CONFIG_PATH options. Instead of building llvm-nm, the build uses
the executable defined by LLVM_NM.
This is useful for cross-compilation scenarios where the host cannot run
the cross-compiled tool, and recursing into another cmake build is not
an option (due to required DEFINE's, for example).
Reviewed By: smeenai
Differential Revision: https://reviews.llvm.org/D83022
This is primarily motivated by the desire to move from Python2 to
Python3. `PYTHON_EXECUTABLE` is ambiguous. This explicitly identifies
the python interpreter in use. Since the LLVM build seems to be able to
completed successfully with python3, use that across the build. The old
path aliases `PYTHON_EXECUTABLE` to be treated as Python3.
This is primarily motivated by the desire to move from Python2 to
Python3. `PYTHON_EXECUTABLE` is ambiguous. This explicitly identifies
the python interpreter in use. Since the LLVM build seems to be able to
completed successfully with python3, use that across the build. The old
path aliases `PYTHON_EXECUTABLE` to be treated as Python3.
Summary:
Most libraries are defined in the lib/ directory but there are also a
few libraries defined in tools/ e.g. libLLVM, libLTO. I'm defining
"Component Libraries" as libraries defined in lib/ that may be included in
libLLVM.so. Explicitly marking the libraries in lib/ as component
libraries allows us to remove some fragile checks that attempt to
differentiate between lib/ libraries and tools/ libraires:
1. In tools/llvm-shlib, because
llvm_map_components_to_libnames(LIB_NAMES "all") returned a list of
all libraries defined in the whole project, there was custom code
needed to filter out libraries defined in tools/, none of which should
be included in libLLVM.so. This code assumed that any library
defined as static was from lib/ and everything else should be
excluded.
With this change, llvm_map_components_to_libnames(LIB_NAMES, "all")
only returns libraries that have been added to the LLVM_COMPONENT_LIBS
global cmake property, so this custom filtering logic can be removed.
Doing this also fixes the build with BUILD_SHARED_LIBS=ON
and LLVM_BUILD_LLVM_DYLIB=ON.
2. There was some code in llvm_add_library that assumed that
libraries defined in lib/ would not have LLVM_LINK_COMPONENTS or
ARG_LINK_COMPONENTS set. This is only true because libraries
defined lib lib/ use LLVMBuild.txt and don't set these values.
This code has been fixed now to check if the library has been
explicitly marked as a component library, which should now make it
easier to remove LLVMBuild at some point in the future.
I have tested this patch on Windows, MacOS and Linux with release builds
and the following combinations of CMake options:
- "" (No options)
- -DLLVM_BUILD_LLVM_DYLIB=ON
- -DLLVM_LINK_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_BUILD_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_LINK_LLVM_DYLIB=ON
Reviewers: beanz, smeenai, compnerd, phosek
Reviewed By: beanz
Subscribers: wuzish, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, mgorny, mehdi_amini, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, dang, Jim, lenary, s.egerton, pzheng, sameer.abuasal, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70179
Due to a misstake with r365902 that tried to simplify the install with
toolchain logic LLVM-C.dll was no longer being installed.
Patch By: Jakob Bornecrantz
llvm-svn: 370271
Summary:
This will simplify the macros by allowing us to remove the hard-coded
list of libraries that should be installed when
LLVM_INSTALL_TOOLCHAIN_ONLY is enabled.
Reviewers: beanz, smeenai
Reviewed By: beanz
Subscribers: aheejin, mehdi_amini, mgorny, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64580
llvm-svn: 365902
Summary:
The MinGW driver for lld does not support the --version-script option.
For GNU ld, it's a no-op since LLVM.dll exports all symbols.
Reviewers: srhines, mstorsjo
Subscribers: mgorny, fedor.sergeev, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63743
llvm-svn: 364343
When we're cross-compiling, build and use a native llvm-nm instead of
attempting to use the one from the target's build tree.
A nice follow-up would be to add a cache variable to allow specifying a
path to an external native llvm-nm instead of building one ourselves,
similar to LLVM_TABLEGEN and LLVM_CONFIG_PATH.
Differential Revision: https://reviews.llvm.org/D60025
llvm-svn: 357487
As discovered in D56774 the command line gets to long, so use a response file
to give the script the libs. This change has been tested and is confirmed
working for me.
Commited on behalf of Jakob Bornecrantz.
Differential Revision: https://reviews.llvm.org/D56781
llvm-svn: 356443
They were breaking the Windows build when using MSBuild, see the
discussion on D56781.
r351833: "Use response file when generating LLVM-C.dll"
> Use response file when generating LLVM-C.dll
>
> As discovered in D56774 the command line gets to long, so use a response file to give the script the libs. This change has been tested and is confirmed working for me.
>
> Commited on behalf of Jakob Bornecrantz
>
> Differential Revision: https://reviews.llvm.org/D56781
r352250: "Build LLVM-C.dll by default on windows and enable in release package"
> Build LLVM-C.dll by default on windows and enable in release package
>
> With the fixes to the building of LLVM-C.dll in D56781 this should now
> be safe to land. This will greatly simplify dealing with LLVM for people
> that just want to use the C API on windows. This is a follow up from
> D35077.
>
> Patch by Jakob Bornecrantz!
>
> Differential revision: https://reviews.llvm.org/D56774
llvm-svn: 352492
As discovered in D56774 the command line gets to long, so use a response file to give the script the libs. This change has been tested and is confirmed working for me.
Commited on behalf of Jakob Bornecrantz
Differential Revision: https://reviews.llvm.org/D56781
llvm-svn: 351833
Summary:
Hello!
This commit adds a LLVM-C target that is always built on MSVC. A big fat warning, this is my first cmake code ever so there is a fair bit of I-have-no-idea-what-I'm-doing going on here. Which is also why I placed it outside of llvm-shlib as I was afraid of breaking things of other people. Secondly llvm-shlib builds a LLVM.so which exports all symbols and then does a thin library that points to it, but on Windows we do not build a LLVM.dll so that would have complicated the code more.
The patch includes a python script that calls dumpbin.exe to get all of the symbols from the built libraries. It then grabs all the symbols starting with LLVM and generates the export file from those. The export file is then used to create the library just like the LLVM-C that is built on darwin.
Improvements that I need help with, to follow up this review.
- Get cmake to make sure that dumpbin.exe is on the path and wire the full path to the script.
- Use LLVM-C.dll when building llvm-c-test so we can verify that the symbols are exported.
- Bundle the LLVM-C.dll with the windows installer.
Why do this? I'm building a language frontend which is self-hosting, and on windows because of various tooling issues we have a problem of consuming the LLVM*.lib directly on windows. Me and the users of my projects using LLVM would be greatly helped by having LLVM-C.dll built and shipped by the Windows installer. Not only does LLVM takes forever to build, you have to run a extra python script in order to get the final DLL.
Any comments, thoughts or help is greatly appreciated.
Cheers, Jakob.
Patch by: Wallbraker (Jakob Bornecrantz)
Reviewers: compnerd, beanz, hans, smeenai
Reviewed By: beanz
Subscribers: xbolva00, bhelyer, Memnarch, rnk, fedor.sergeev, chapuni, smeenai, john.brawn, deadalnix, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D35077
llvm-svn: 339151
Summary:
This option is no longer needed since r300496 added symbol
versioning by default
Reviewers: sylvestre.ledru, beanz, mgorny
Reviewed By: mgorny
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49835
llvm-svn: 338751
Fuchsia uses ELF as a file format and LLD as the linker so we can
use the same implementation as other ELF based platforms.
Differential Revision: https://reviews.llvm.org/D46991
llvm-svn: 332570
Shared-library build on Solaris requires --whole-archive to be specified (option accepted by all available linkers).
At the same time, --version-script can not be handled by Solaris-ld, so it should be skipped.
-M is of no use here, since there is no syntax in Solaris-ld mapfiles that allows to version all global symbols,
not just the named ones (at least this is my impression from digging deep into the docs).
Patch by Fedor Sergeev <fedor.sergeev@oracle.com>
llvm-svn: 308490
Haiku uses GNU ld for linking, but is not captured in the
conditional when setting LIB_NAMES. This causes a shared
library with no symbols on Haiku. This patch simply adds
a check for whether the CMake system name is Haiku in
addition to the existing checks.
Patch by Jérôme Duval.
Differential Revision: https://reviews.llvm.org/D34998
llvm-svn: 307607
Summary:
When apps or other libraries link against a library with symbol
versions, the version string is recorded in the import table, and used
at runtime to resolve the symbol back to a library that provides that
version (vaguely like how two-level namespaces work in Mach-O). ld's
--default-symver flag tags every exported symbol with a symbol version
string equal to the library's soname. Using --default-symver means
multiple versions of libLLVM can coexist within the same process, at
least to the extent that they don't try to pass data between each
other's llvms.
As an example, imagine a language like Rust using llvm for CPU codegen,
binding to OpenGL, with Mesa as the OpenGL implementation using llvm for
R600 codegen. With --default-symver Rust and Mesa will resolve their
llvm usage to the version each was linked against, which need not match.
(Other ELF platforms like BSD and Solaris might have similar semantics,
I've not checked.)
This is based on an autoconf version of this patch by Adam Jackson.
This new option can be used to add --default-symver to the linker flags
for libLLVM.so.
Reviewers: beanz
Reviewed By: beanz
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D30997
llvm-svn: 302026
Summary:
This patch adds a very simple linker script to version the lib's symbols
and thus trying to avoid crashes if an application loads two different
LLVM versions (as long as they do not share data between them).
Note that we deliberately *don't* make LLVM_5.0 depend on LLVM_4.0:
they're incompatible and the whole point of this patch is
to tell the linker that.
Avoid unexpected crashes when two LLVM versions are used in the same process.
Author: Rebecca N. Palmer <rebecca_palmer@zoho.com>
Author: Lisandro Damían Nicanor Pérez Meyer <lisandro@debian.org>
Author: Sylvestre Ledru <sylvestre@debian.org>
Bug-Debian: https://bugs.debian.org/848368
Reviewers: beanz, rnk
Reviewed By: rnk
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D31524
llvm-svn: 300496
Summary:
This fixes a few things that used to work with a Makefile build, but were broken in cmake.
1. Treat MINGW like a Linux system.
2. The shlib should never contain other shared libraries.
Patch By: Valentin Churavy
Reviewers: axw, beanz
Subscribers: modocache, beanz, mgorny
Differential Revision: https://reviews.llvm.org/D25865
llvm-svn: 285737
This should actually address PR27855. This results in adding references to the system libs inside generated dylibs so that they get correctly pulled in when linking against the dylib.
llvm-svn: 270723
Autoconf used to support setting LLVM_VERSION_INFO and there is some code filtered around llvm in Support/CommandLine.cpp and LTO/LTOCodeGenerator.cpp that uses it if it is set.
We also shouldn't be explicitly setting it as a define on llvm-shlib. It is pointless there because there is no code using it in llvm-shlib, and it is better to have it as part of the generated config.h so that it is available everywhere.
llvm-svn: 267490
Summary:
This change makes the CMake build system generate libraries for Linux and Darwin matching the makefile build system.
Linux libraries follow the pattern lib${name}.${MAJOR}.${MINOR}.so so that ldconfig won't pick it up incorrectly.
Darwin libraries are not versioned.
Note: On linux the non-versioned symlink is generated at install-time not build time. I plan to fix that eventually, but I expect that is good enough for the purposes of fixing this bug.
Reviewers: loladiro, tstellarAMD
Subscribers: axw, llvm-commits
Differential Revision: http://reviews.llvm.org/D13841
llvm-svn: 252093
Summary:
We've had a lot of discussion in the past about the meaningful and useful default behaviors for the llvm-shlib tool. The original implementation was heavily geared toward Apple's use, and I think that was wrong. This patch seeks to correct that.
I've removed the LLVM_DYLIB_EXPORT_ALL variable and made libLLVM export everything by default.
I've also added a new target that is only built on Darwin for libLLVM-C as a library that re-exports the LLVM-C API. This library is not built on Linux because ELF doesn't support re-export libraries in the same way MachO does.
Reviewers: chapuni, resistor, bogner, axw
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13842
llvm-svn: 251411
Summary:
This diff attempts to address the concerns raised in
http://reviews.llvm.org/D12488.
We introduce a new USE_SHARED option to llvm_config,
which, if set, causes the target to be linked against
libLLVM.
add_llvm_utility now uniformly disables linking against
libLLVM. These utilities are not intended for distribution,
and this keeps the option handling more centralised.
llvm-shlib is now processes before any other "tools"
subdirectories, ensuring the libLLVM target is defined
before its dependents.
One main difference from what was requested: llvm_config
does not prune LLVM_DYLIB_COMPONENTS from the components
passed into explicit_llvm_config. This is because the "all"
component does something special, adding additional
libraries (namely libLTO). Adding the component libraries
after libLLVM should not be a problem, as symbols will be
resolved in libLLVM first.
Finally, I'm not really happy with the
DISABLE_LLVM_LINK_LLVM option, but I'm not sure of a
better way to get the following:
- link all tools and shared libraries to libLLVM if
LLVM_LINK_LLVM_DYLIB is set
- some way of explicitly *not* doing so for utilities
and libLLVM itself
Suggestions for improvement here are particularly welcome.
Reviewers: beanz
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12590
llvm-svn: 246918
Summary:
Three closely related changes, to have a mode in which we link all
executables and shared libraries against libLLVM.
1. Add a new LLVM_LINK_LLVM_DYLIB cmake option, which, when ON, will link
executables and shared libraries against libLLVM. For this to work, it
is necessary to also set LLVM_BUILD_LLVM_DYLIB and LLVM_DYLIB_EXPORT_ALL.
It is not strictly necessary to set LLVM_DISABLE_LLVM_DYLIB_ATEXIT, but
we also default to OFF in this mode, or tools tend to misbehave (e.g.
stdout may not flush on exit when output is buffered.)
llvm-config and Tablegen do not use libLLVM, as they are dependencies of
libLLVM.
2. Modify llvm-go to take a new flag, "linkmode=component-libs|dylib".
Depending on which one is passed (default is component-libs), we link
with the individual libraries or libLLVM respectively. We pass in dylib
when LLVM_LINK_LLVM_DYLIB is ON.
3. Fix LLVM_DYLIB_EXPORT_ALL on Linux, and expand the symbols exported to
actually export all. Don't strip leading underscore from symbols on Linux,
and make sure we get all exported symbols and weak-with-default symbols
("W" in nm output). Without these changes, passes won't load because
the "Annotate..." symbols defined in lib/Support/Valigrind.cpp are not
found.
Testing:
- Ran default build ("ninja") with LLVM, clang, compiler-rt, llgo, lldb.
- Ran "check", "check-clang", "check-tsan", "check-libgo" targets. I've
never had much success with LLDB tests, and llgoi is currently broken
so check-llgo fails for an unrelated reason.
- Ran "lldb" to ensure it loads.
Reviewers: chandlerc, beanz, pcc, rnk
Subscribers: rnk, chapuni, sylvestre.ledru, llvm-commits
Differential Revision: http://reviews.llvm.org/D12488
llvm-svn: 246527
folding the code into the main Analysis library.
There already wasn't much of a distinction between Analysis and IPA.
A number of the passes in Analysis are actually IPA passes, and there
doesn't seem to be any advantage to separating them.
Moreover, it makes it hard to have interactions between analyses that
are both local and interprocedural. In trying to make the Alias Analysis
infrastructure work with the new pass manager, it becomes particularly
awkward to navigate this split.
I've tried to find all the places where we referenced this, but I may
have missed some. I have also adjusted the C API to continue to be
equivalently functional after this change.
Differential Revision: http://reviews.llvm.org/D12075
llvm-svn: 245318
Martin Storsjö