Extract the effective linker during the computation of implicit artifacts
delivered by the compiler to the linker.
Define various variables describing the linker:
* CMAKE_<LANG>_COMPILER_LINKER
* CMAKE_<LANG>_COMPILER_LINKER_VERSION
* CMAKE_<LANG>_COMPILER_LINKER_ID
* CMAKE_<LANG>_COMPILER_LINKER_FRONTEND_VARIANT
This is complementary to feature introduced by commit 96a953b1ed
(Add options to specify linker tool, 2023-09-27).
Fixes: #17596, #18209, #25344
These are printed by LLVM-based compiler drivers targeting the MSVC ABI.
In our use case for this, `CMAKE_LINKER` may not yet be known, so do
not include it in the test data.
Divert LCC compiler as a new one, instead of treating it as GNU.
Since old times, Elbrus C/C++/Fortran Compiler (LCC) by MCST has been
passing checks for GNU compilers, so it has been identified as GNU.
Now, with intent of seriously upstreaming its support, it has been
added as a separate LCC compiler, and its version displays not a
supported GCC version, but LCC version itself (e.g. LCC 1.25.19 instead
of GNU 7.3.0).
This commit adds its support for detection, and also converts basically
every check like 'is this compiler GNU?' to 'is this compiler GNU or
LCC?'. The only places where this check is untouched, is where it
regards other platforms where LCC is unavailable (primarily non-Linux),
and where it REALLY differs from GNU compiler.
Note: this transition may break software that are already ported to
Elbrus, but hardly relies that LCC will be detected as GNU; still such
software is not known.
With flags like `-static-libstdc++` or `-static-libgfortran`, the GNU
compiler driver adds `-Bstatic ... -Bdynamic` around its language
runtime library. Convert the libraries in between these to absolute
paths so that mixed-language linking honors the static runtime
libraries.
The NVHPC compiler does not have any implicit link directories that can
be used to detect `CMAKE_LIBRARY_ARCHITECTURE`, but it does have
implicit object files. Extract implicit object file paths from link
lines and check them for the `CMAKE_LIBRARY_ARCHITECTURE` pattern.
Issue: #22024
It is currently presumed that the linker will generate
a space separated line. This is not the case for some
compilers such as IBM XL where it can output space or
comma separated. This is particularly apparent when IBM XL
is used as the host compiler for CUDA as it generates a comma
separated link line.
CMakeParseImplicitLinkInfo tests arbitrary content with `if(MATCHES)`.
Set policy CMP0054 to ensure the line content is never interpreted as a
variable reference (which may also produce a CMP0054 warning).
While at it, also set policy CMP0053 to improve performance.
Extend the fix in commit v3.9.6~1^2 (Restore exclusion of "gcc_eh" from
implicit link libraries, 2017-11-07) to also exclude `gcc_eh` libraries
referenced by absolute path to the library file.
Issue: #17436
Since commit v3.9.0-rc1~148^2 (Do not assume GCC libs are linked by all
compilers, 2017-05-05) we no longer filter out all `gcc*` implicit link
libraries. This allows mixing of gcc and non-gcc compilers across
languages. However, this caused a subtle problem with how GCC makes
exception handling symbols available to linked binaries.
GCC (at least on MinGW) provides two different libraries with exception
handling symbols:
* gcc_s: A shared library with -fvisibility=default, used by -shared-libgcc.
* gcc_eh: A static library with -fvisibility=hidden, used by -static-libgcc.
The C compiler (on MinGW) defaults to -static-libgcc and uses gcc_eh.
The C++ compiler defaults to -shared-libgcc and uses gcc_s when linking
shared libraries and executables so that exceptions can propagate across
shared libraries [1]. When linking a mixed-language binary, the C++
compiler should be used along with its choice of gcc_s. In this case
gcc_eh should not be added even though the C compiler implies it because
gcc_s supersedes it.
Since the above-mentioned change, CMake is adding gcc_eh to C++ link
lines that also contain C code on MinGW. This causes both gcc_s and
gcc_eh to be used, which is incorrect. We can fix this simply by
excluding gcc_eh from the C compiler's implicit link libraries.
[1] https://gcc.gnu.org/onlinedocs/gcc-7.2.0/gcc/Link-Options.html#Link-OptionsFixes: #17436
Since PGI does not write linker directives into objects, the necessary
libraries have to be parsed from commandline. PGI does however link the
Visual C++ runtime libraries, so they have to be filtered out to ensure
no collision with settings of other languages can occur.
The `ld` tool in Xcode 8.3 now has a `-lto_library <path>` flag. Ignore
the flag instead of accidentally parsing it as `-l` with `to_library`.
Fixes: #16766
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool. Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience. Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.
Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices. It also references version control
history for more precise information. Therefore we no longer need to spell
out the list of Contributors in each source file notice.
Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing". The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.
Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically. Manually fix up shebang lines and trailing
newlines in a few files. Manually update the notices in a few files that the
script does not handle.
These libraries are used for Clang runtime analysis support with
flags like `-fsanitize=memory` and are not actually implicitly
linked libraries.
Fixes#16194.
PathScale uses a wrapper around the linker. The "ldfe" invocation in
the output is followed by a normal "ld" invocation. Exclude the former
so we can reach and parse the latter correctly.
When compiling with
LDFLAGS='-Wl,-z,relro -specs=/usr/lib/rpm/redhat/redhat-hardened-ld'
the compiler output includes a line like
COLLECT_GCC_OPTIONS='-specs=/usr/lib/rpm/redhat/redhat-hardened-ld' ...
that our link line regex matches due to an argument ending in "-ld".
Since it is not really the link line no implicit link information is
dectected. Exclude "VAR=..." lines from consideration as link lines to
fix this.
When matching implicit library names, use a sentinel "x" to avoid
ever expanding the library name as a variable. This was detected
by a CMP0054 warning.
In commit v3.1.0-rc1~640^2~5 (Clean up usage of if(... MATCHES regex)
followed string(REGEX REPLACE regex), 2014-04-06) we accidentally broke
logging of the implicit library detection. Restore use of the
intermediate 'lib' variable so that the log message is constructed
properly.
Reported-by: Bill Somerville <bill@classdesign.com>
The matches have already been calculated and can simply be taken from
CMAKE_MATCH_n variables. This avoids multiple compilations of the same or very
similar regular expressions.
Teach CMakeParseImplicitLinkInfo to convert the CMAKE_LINKER file name
to a regular expression that matches only the original name. Escape
special characters like '+' so they are not treated as regex syntax.
Extend the ImplicitLinkInfoTest to test handling of a CMAKE_LINKER value
with many special characters.
Teach CMakeParseImplicitLinkInfo to convert implicit link library full
paths to a canonical form. This makes them more reproducible in case
different language compiler front-ends add the same library by different
paths e.g. ".../libA.a" and "...//libA.a".
Add a case to the CMake.ImplicitLinkInfo test to cover removal of extra
slashes from both library and directory paths.
Previously we hard-coded a list of implicit framework directories but
did not account for CMAKE_OSX_SYSROOT or for changes to the list across
OS X versions. Instead we should automatically detect the framework
directories for the active toolchain.
The parent commit added the "-Wl,-v" option to ask "ld" to print its
implicit directories. It displays a block such as:
Framework search paths:
/...
Parse this block to extract the list of framework directories.
Detection may fail on toolchains that do not list their framework
directories, such as older OS X linkers. Always treat the paths
<sdk>/Library/Frameworks
<sdk>/System/Library/Frameworks
<sdk>/Network/Library/Frameworks # Older OS X only
/System/Library/Frameworks
as implicit. Note that /System/Library/Frameworks should always be
considered implicit so that frameworks CMake finds there will not
override the SDK copies.
We detect the implicit link directories for the toolchain by adding a
flag to get verbose output from the compiler front-end while linking the
ABI detection binary. Newer OS X toolchains based on Clang do not add
the implicit link directories with -L options to their internal
invocation of "ld". Instead they use a linker that comes with the
toolchain and is already configured with the proper directories.
Add the "-Wl,-v" option to ask "ld" to print its implicit directories.
It displays them in a block such as:
Library search paths:
/...
Parse this block to extract the implicit link directories.
While at it, remove the checks introduced by commit efaf335b (Skip
implicit link information on Xcode, 2009-07-23) and commit 5195a664
(Skip implicit link info for multiple OS X archs, 2009-09-22). Discard
the non-system link directories added by Xcode. Discard all detected
implicit libraries in the multi-architecture case but keep the
directories. The directories are still useful without the libraries
just to suppress addition of explicit -L options for them.
Use the "-X -v" flag to the Absoft front-end to pass "-v" to the gcc it
invokes under the hood. Teach CMakeParseImplicitLinkInfo to exclude
linker version lines from consideration as link lines. Fix parsing of
Sun's linker search path option "-Y..." to avoid conflict with the Mac
linker option "-Y<num>".
The NAG Fortran compiler implicitly passes object files by full path to
the linker. Teach CMakeParseImplicitLinkInfo to parse object files that
match some tool-specific regular expression.
Some compilers use implicit link options of the form
-lcrt*.o
-lgcc*
-lSystem (on Mac)
-lSystemStubs (on Mac)
that provide system-wide symbols not specific to any language.
These need not be listed explicitly for mixed-language linking.
We teach CMake to remove the above items from the implicit library list
of each language. This change makes it possible to mix GNU compiler
versions in some cases.
The regex used by CMAKE_PARSE_IMPLICIT_LINK_INFO to detect link lines
should not match lines that happen to have ".../ld.../..." in them. A
linker name should match only as the last component of a path.
See issue #9666.
This commit teaches the CMAKE_PARSE_IMPLICIT_LINK_INFO function to log
the regex it uses to detect the linker invocation line. The regex is
computed from the CMAKE_LINKER if it is found, so it might change. A
strange value might match the wrong line and cause implicit link info
extraction to fail.
See issue #9666.
This commit teaches the CMAKE_PARSE_IMPLICIT_LINK_INFO function to log
its actions. We store the log in CMakeFiles/CMakeOutput.log at the top
of the project build tree. This will make diagnosis of implicit link
information parsing problems easier.
This adds copyright/license notification blocks CMake's non-find
modules. Most of the modules had no notices at all. Some had notices
referring to the BSD license already. This commit normalizes existing
notices and adds missing notices.
This teaches the implicit link line parsing code to recognize link lines
that do not have a full path to the linker executable. At least one
version of the Intel compiler on Linux invokes the linker as just "ld"
instead of "/usr/bin/ld".
The Sun Fortran compiler passes -zallextract and -zdefaultextract to the
linker so that all objects from one of its archives are included in the
link. This teaches the implicit options parser to recognize the flags.
We need to pass them explicitly on C++ link lines when Fortran code is
linked.
This teaches CMake to detect implicit link information for C, C++, and
Fortran compilers. We detect the implicit linker search directories and
implicit linker options for UNIX-like environments using verbose output
from compiler front-ends. We store results in new variables called
CMAKE_<LANG>_IMPLICIT_LINK_LIBRARIES
CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES
The implicit libraries can contain linker flags as well as library
names.
Brad King