Dynamically loaded plugins for the new pass manager are initialised by
calling llvmGetPassPluginInfo. This is defined as a weak symbol so that
it is continually redefined by each plugin that is loaded. When loading
a plugin from a shared library, the intention is that
llvmGetPassPluginInfo will be resolved to the definition in the most
recent plugin. However, using a global search for this resolution can
fail in situations where multiple plugins are loaded.
Currently:
* If a plugin does not define llvmGetPassPluginInfo, then it will be
silently resolved to the previous plugin's definition.
* If loading the same plugin twice with another in between, e.g. plugin
A/plugin B/plugin A, then the second load of plugin A will resolve to
llvmGetPassPluginInfo in plugin B.
* The previous case can also occur when a dynamic library defines both
NPM and legacy plugins; the legacy plugins are loaded first and then
with `-fplugin=A -fpass-plugin=B -fpass-plugin=A`: A will be loaded as
a legacy plugin and define llvmGetPassPluginInfo; B will be loaded
and redefine it; and finally when A is loaded as an NPM plugin it will
be resolved to the definition from B.
Instead of searching globally, restrict the symbol lookup to the library
that is currently being loaded.
Differential Revision: https://reviews.llvm.org/D104916
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
Aaron Ballman reported that TestPlugin warned about it using exception handling
without /EHsc flag, and that llvmGetPassInfo() had conflicting export
attributes (dllimport in the header, dllexport in the source file).
/EHsc is because TestPlugin didn't use the llvm_ cmake functions, so
llvm_update_compile_flags didn't get called for the target
(llvm_update_compile_flags explicitly passes /Ehs-c-, which fixes the warning).
Use add_llvm_loadable_module instead of add_library(... MODULE) to fix this.
This also has the side effect of not building the plugin on Windows. That's not
a big problem, since before the plugin was built on Windows, but the test
didn't attempt to load it, due to -DLLVM_ENABLE_PLUGIN not being passed to
PluginsTests.cpp during compilation on Windows. This makes the plugin behavior
consistent with e.g. lib/Transforms/Hello/CMakeLists.txt. (This also
automatically sets LTDL_SHLIB_EXT correctly.)
The dllimport/dllexport warning is more serious: Since LLVM doesn't generally
use export annotations for its code, the only way the plugin could link was by
linking in some LLVM libraries both into the test and the dll, so the plugin
would call the llvm code in the dll instead of the copy in the main executable.
This means globals weren't shared, and things generally can't work. (I think
there's a build config where you can build a LLVM.dll which might work, but
that wasn't how the test was configured. If that config is used, the dll should
still be built, but I haven't checked).
Now that add_llvm_loadable_module is used, LLVM_LINK_COMPONENTS got linked into
both executable and plugin on posix too, so unset it after the executable so
that the plugin doesn't end up with a 2nd copy of things on posix.
https://reviews.llvm.org/D47082
llvm-svn: 332796
LLVM uses cpp as its C++ file extension, these are the only three cxx file in
the monorepo. These files apparently were called to escape a CMake check -- use
the LLVM_OPTIONAL_SOURCES mechanism that's meant as an escape for this case
instead.
No intended behavior change.
https://reviews.llvm.org/D46843
llvm-svn: 332368
