This adds the following:
- LLD now uses the SOURCE_DATE_EPOCH env variable for setting the
COFF header timestamp
- LLD now also supports --lto-emit-asm and -plugin-opt=emit-llvm
in the mingw linker interface
Since cpython-mingw v3.11 (see cpython-mingw commit
8aeb46d09c068a1228e83b29101c17bf1ff0612a), the versionless, stable
ABI libpython3.dll gets installed, along with libpython3.dll.a.
Ideally we would use this, which gets us better flexibility, but
in practice, LLDB fails to link against this, as it doesn't expose
enough of the symbols we use and need.
Previously, we ended up with PYTHON_LIB containing two path names,
which caused CMake to print warnings about ignoring extra paths
on the command line.
This fixes issue #396.
Relevant changes/fixes since the last version:
- Added the new Clang option -fno-auto-import, affecting both code
generation (avoiding generating .refptr stubs) and linking
(passing --disable-auto-import, to avoid subtle runtime errors,
which could happen if code built without .refptr stubs would
autoimport symbols anyway)
- Fix issues with running the toolchain, or building sources on,
network mounts. Previously, there were issues with VirtualBox
shared folders or Remote Desktop shared folders.
- Pass LTO options from the compiler driver to the linker
- Support more LTO options in the linker
- LLD now implements the --icf=safe option properly
- Support using the -S/-s flags in LLD, to strip out DWARF debug
info and symbol table, while producing a PDB file
- Fix LTO issues around __imp_ symbols, making it support building
the base mingw-w64-crt files with LTO
- LLD now doesn't try to detect/add MSVC library directories when
linking in MinGW mode
- Fix building compiler-rt sanitizers, when libcxx is available only
in static form
- Fix building a standalone libclang_rt.atomic_dynamic for MinGW
targets
- Support for the MENUEX resource type in llvm-windres
- llvm-windres now supports referencing filenames in .rc files,
constructed from multiple concatenated string literals
- Various fixes for the llvm-windres option --preprocessor, including
the breaking change to match the new GNU windres behaviour from
binutils 2.36
- Don't look for a GCC in path when Clang is installed next to
a suitable sysroot (mostly relevant for MSYS2)
- Avoid exposing unprefixed mmap symbols in the profiling runtime,
which could lead to misdetections in user code
- Support for reading Windows thread names in LLDB
This version fixes the following issues for mingw/windows targets:
- Fix linking the lli tool if built with asan enabled
- Fix compiling for the aarch64 target if specifying -mtune=cortex-a53
- Fix initialization order among constructors within one translation unit
This contains a few bugfixes for mingw use cases:
- LLD in 17.0.1 and the earlier 17.x release candidates looked up
libraries (including libraries named as a relative path) preferring
to search in toolchain relative paths over first testing from the
current directory. In some cases, this could cause cryptic build
failures; see https://github.com/llvm/llvm-project/issues/67779.
- Options that only are relevant for linking, like -mwindows, used
to be accepted (but produce a warning) if used in a compilation-only
job. In the earlier 17.x releases/RCs, such warnings caused an
error instead; see https://github.com/llvm/llvm-project/issues/64464
and https://github.com/mstorsjo/llvm-mingw/issues/371.
This only provides the main binary llvm-cxxfilt; it doesn't
provide the binutils-style frontends named [<triple>-]c++filt.
If we were to provide such frontends, we'd need to make them
default to --strip-underscore for i686 triple prefixes, and
for the prefixless case when the default architecture is i686.
This allows simplification, this functionality was added long
ago to CMake.
Further motivation is to be able to re-direct the installation,
make/ninja install allow this by setting DESTDIR but this
generally doesnt work well with window paths (see [1]).
[1] - https://cmake.org/cmake/help/latest/envvar/DESTDIR.html#envvar:DESTDIR
There was a minor issue with the version information in what
was tagged as 17.0.0, so 17.0.1 is the first proper stable
release on the 17.x release branch.
Relevant changes since 16.0.6 are:
- Improve Address Sanitizer on i686 mingw
- Improve handling of X86 Intel assembly syntax
- Fix using std::wcout/wcin/wcerr with streams configured in wide mode
- Improve handling of the .arch and .arch_extension assembly directives
on aarch64
- Support the --temp-prefix (ignored) and --no-leading-underscore
options in llvm-dlltool
- Make lld warn about too narrow pseudo relocations, simplifying finding
issues that otherwise only show up at runtime
- Improved the tests, making compiler-rt, libcxxabi and libunwind tests
pass in mingw configurations
A couple relevant changes since 16.0.0:
- Fix compilation for ARM (failures in generating SEH unwind info)
for very specific cases
- Link the ASAN DLL before other libs and objects, to make sure it gets
initialized as early as possible
- Allow double backslashes in the PATH in ASAN
- Allow llvm-rc to look for a clang executable named "clang-16", if the
other alternatives aren't available
- Improve the performance of buffered raw_ostream within LLVM
Normally our releases are cross-built from Linux, but we also
support building the toolchain in MSYS2. Enable the custom defaults
when building the toolchain in MSYS2 too.
Notable changes for mingw users are:
- Support demangling C++ symbols on i386 in LLVM backtraces
- Don't report fatal errors when the output pipe is closed on Windows
- Ignore file access times on Windows when comparing whether files are
equivalent
Notable changes are:
- Emit -exclude-symbols: directives for hidden symbol visibility (supported
by LLD 15 and binutils ld 2.40). This allows reducing the number of
exported symbols in e.g. libLLVM-*.dll.
- Support for CFGuard on mingw, thanks to Alvin Wong!
- LLD now picks up libraries named <name>.lib when linking with -l<name>,
even if -static was specified
- Fixed SEH unwind info on AArch64 if using the AArch64 feature
PAC (Pointer Authentication Code) - previously, unwinding would fail if
running on a system that actually does use the feature. (The consistency
of AArch64 SEH unwind info was also improved for other cases.)
- Fixed stack alignment on AArch64, for stack frames large enough to
require stack probing
- Fixed llvm-objcopy corrupting some cases of object files with empty sections
- Improvements to LLDB, where it now uses the regular symbol list of DLLs
(including non-exported symbols)
- OpenMP now can be built and works on armv7 and aarch64 (in mingw
configurations)
Notable for simplifying how to cross compile LLVM itself:
- The preexisting build machine tools can be specified with one single option
LLVM_NATIVE_TOOL_DIR instead of passing a number of variables like
LLVM_TABLEGEN, CLANG_TABLEGEN etc.
This option was mostly relevant for making it possible to share
ccache between builds in different directories, due to specific
logic in CMake's Ninja generator, which used relative paths for
sources as long as they were below the main source directory
(llvm-project/llvm). This option wasn't usable on Windows.
Since CMake 3.21.0, this option no longer worked for the intended
purpose - that version of CMake changed the Ninja generator to
always use absolute paths to sources, for consistency with other
generators and to simplify things. (See commit
c564a3e3fff52ef811291c5ba8fb07a5a1b47f97 in CMake's git history.)
It is still possible to achieve ccache sharing across build
directories anyway, by setting the ccache option CCACHE_BASEDIR,
which makes ccache rewrite absolute paths to relative ones within
that tree, and by setting the LLVM CMake option
LLVM_USE_RELATIVE_PATHS_IN_FILES=ON, which adds -ffile-prefix-map
options to the compiler, to remap source paths as they are exposed
in the generated code.
(Strictly speaking, LLVM_USE_RELATIVE_PATHS_IN_FILES is only needed
if debug info is enabled. On its own, without CCACHE_BASEDIR, that
option produces compiler output that is identical across build
directories - but the absolute paths end up in the preprocessor output
in source file/line comments, which makes ccache fail to reuse the cache.)
When rebuilding in an already built directory, cmake does use
the cache file, containing what variables were set to previously.
When changing build configuration (building with a different prefix,
or changing build configurations) this can often result in failed
cmake runs.
Wipe the cache (and the rest of the cmake temp files) by default.
This makes sure that the full cmake configuration is run each time
when running the build scripts, just like it does the first time.
(This doesn't remove the build artifacts; if nothing of significance
has changed, ninja would still reuse old built files.)
By setting the env variable NO_RECONF, this behaviour can be skipped,
rerunning cmake without wiping the cache inbetween. (For cases where
the user knows that the configuration hasn't changed since the last
build, this can speed up the cmake execution time a bit.)
Notable changes are:
- Require strict matches for defines for precompiled headers in GCC
style PCH directories. This fixes some cases of building DLLs and
static libraries at the same time with libtool, with PCH.
- Support for the new embedded -exclude-symbols: directive in LLD
- Fix LLD crashes if including object files containing export directives
via the --undefined/-u option
This avoids needing to run the cmake configure for the nested
native build.
This tool (part of clang-tools-extra) is new in LLVM 15.0.0
(and the cmake setting for specifying the binary was backported
after the 15.x branch was made, but before rc1 was tagged).
This command isn't a standard tool; different distributions have
different implementations, and e.g. Fedora doesn't ship it by
default.
Settle on using "command -v $tool >/dev/null" for tests about whether
a tool is available. (We could also use "hash $tool 2>/dev/null" as we
already had in build-all.sh, but settling on using "command -v"
everywhere, for consistency and simplicity.)
Since 93010544a813dfbfa64dd7cee68785f572f974d1 in llvm-project
(Jun 22nd), this no longer is needed for being able to build
native tools with a nested cmake in a cross build. (If building in
the same tree as a previous native build, build-llvm tries to pick
up the tblgen tools from there, so in such cases, this doesn't
make any difference and the nested native cmake invocation never
was executed.)
Martin Storsjö