Teach CMake to prefer the system default compiler automatically when no
compiler is specified. By default use "cc" for C, "CC" for C++, and
"f95" for Fortran. Load a new Platform/<os>-<lang>.cmake module to
allow each platform to specify for each language its system compiler
name(s) and/or exclude certain names.
Create Platform/(CYGWIN|Darwin|Linux|Windows)-CXX.cmake modules to
specify "c++" as the system C++ compiler name for these platforms. On
systems that use case-insensitive filesystems exclude C++ compiler names
that are distinguished from C compiler names only by case.
This will change the default compiler selection for existing build
scripts that do not specify a compiler when run on machines with
separate system and GNU compilers both installed in the PATH. We do not
make this change in default behavior lightly. However:
(1) If a given build really needs specific compilers one should specify
them explicitly e.g. by setting CC, CXX, and FC in the environment.
(2) The motivating case is to prefer the system Clang on newer OS X
systems over the older GNU compilers typically also installed. On
such systems the names "cc" and "c++" link to Clang. This is the
first platform known to CMake on which "c++" is not a GNU compiler.
The old behavior selected "gcc" for C and "c++" C++ and therefore
chooses GNU for C and Clang for C++ by default. The new behavior
selects GNU or Clang consistently for both languages on older or
newer OS X systems, respectively.
(3) Other than the motivating OS X case the conditions under which the
behavior changes do not tend to exist in default OS installations.
They typically occur only on non-GNU systems with manually-installed
GNU compilers.
(4) The consequences of the new behavior are not dire. At worst the
project fails to compile with the system compiler when it previously
worked with the non-system GNU compiler. Such failure is easy to
work around (see #1).
In short this change creates a more sensible default behavior everywhere
and fixes poor default behavior on a widely-used platform at the cost of
a modest change in behavior in less-common conditions.
The compiler candidate list selection and search code for C, C++, ASM,
and Fortran languages was duplicated across four modules. To look for
compilers adjacent to already-enabled languages the C and CXX modules
each used _CMAKE_USER_(C|CXX)_COMPILER_PATH and the ASM module used
_CMAKE_TOOLCHAIN_LOCATION. Since commit 4debb7ac (Bias Fortran compiler
search with C/C++ compilers, 2009-09-09) CMake prefers Fortran compilers
matching the vendor and directory of an enabled C or C++ compiler.
Factor out the common functionality among the four languages into a new
CMakeDetermineCompiler module. Generalize the Fortran implementation so
that all languages may each use the vendor and directory of the other
languages that have already been enabled. For now do not list any
vendor-specific names for C, C++, or ASM so that only the directory
preference is used for these languages (existing behavior).
Look for "clang" or "clang++" compiler executables so Clang will be used
when it is the only compiler available. Prefer them last to avoid
changing compiler default preferences for existing scripts.
In case that any of the input variables that hold the library names contains
more than just a single library the "debug" or "optimized" keywords were only
prepended to the first item, making all other libs appear in all
configurations. Just treat both input variables as lists.
Thanks to Philipp Berger <newsletters@philippberger.de> for pointing me at
this.
1fc8df9 Add missing this->.
7a3ecf5 Fix memory leak in Makefile generator.
9f7dc83 Ninja: also bootstrap ninja files
5d365b2 Ninja: enable ninja support everywhere
d569f3e Ninja: void function can't return a value
52160bf Ninja: enable ninja on Mac so all Mac CDash-builds are tested, cleanup later
56aeac6 Ninja: fixes for bcc
7a6bc9e Ninja: remove 'this' from member initializer list
44ba4cf Ninja: remove warnings
7751966 Ninja: remove 'friend' in ninja code
c3988ee Re-factor OS X content generator start up.
f8e0a51 Re-factor framework directory computation.
f36c7b0 Re-factor Mac OS X content directory computation.
5d885db Re-factor bundle content copying rules generation.
3b2a01e Ninja: Use same echo message as makefiles.
7bb56c5 Re-factor CFBundle generation.
...
b47cffa CPack: Use bin subdir when looking for dpkg and rpmbuild
a8c659c Find dpkg and rpmbuild in usual Fink and MacPort paths
848f220 Do not run cpack at CMake time it is not available.
9e30289 Ninja: Cannot pass a reference to an anonymous object.
0a3d6a1 Ninja: make debug symbol suffix configurable by CMAKE_DEBUG_SYMBOL_SUFFIX
75bbffb Ninja: make TARGET_PDB a real .gdb file name
e5a27a4 Ninja: line length
ae8124a Ninja: also mingw needs TARGET_PDB
207ec5c Ninja: fix mis-matching endif() argument
392a654 Ninja: on Mac no multiple -arch because of -M
801f23f Ninja: dep files and multiple -arch flags not possible on mac
74d1c88 Ninja: cmcldeps needs absolute paths for RCs
1cdeef7 Ninja: readd quotes to src file path before patching it
84a18cb Ninja: also stop when .rc's .d file couldn't be generated
c864103 Ninja: path is already declared
6547f36 Ninja: more searching for windres
78588e0 Ninja: there could be null pointers
0c89c10 Ninja: search for windres with prefix
4654680 Ninja: windres is also used for cross-compiling
When a search path contains multiple "lib/" instances we previously
converted all or none. This fails for cases where only some of the
multiple instances must be converted. Teach AddArchitecturePaths to
generate all combinations that exist. Uncomment these cases in the
CMakeOnly.find_library test now that they work.
Simplify cmFindLibraryCommand::AddArchitecturePaths logic to avoid
recording a separate 'found' status and populating an entire
vector<string> just to throw it away.
Previously methods AddArchitecturePaths and AddLib64Paths were almost
identical. Replace the latter with a call to the former. Fix the
AddArchitecturePaths implementation to add trailing slashes to all
tested paths.
Add a "CMakeOnly.find_library" test covering various cases involving
lib->lib64 (non-)conversion. Comment out cases involving mixed path
components "lib" and "lib64", such as lib/A/lib64 and lib64/A/lib, as
these are known to be broken currently.
Brad King
Kitware Robot
Rolf Eike Beer
Alex Neundorf
David Cole
Nicolas Despres
Bill Hoffman
Peter Kümmel