Zephyr is a bare metal build where standard libs are disabled.
This means that c and runtime libraries must manually be linked in.
This has generally been handled by using CMake's link libraries handling
but the issue with that is both de-duplication but also library link
order.
Standard libraries must be linked at last location to ensure symbols
are always available, however this is not optimal with
target_link_libraries() because this would ultimately require every
library to know the c library to link with, which is not desired.
Therefore, setup standard C and runtime library linking in linker
CMake files for toolchains where this is required.
This commit expands the principle introduced with toolchain abstraction,
see PR#24851.
This means that a toolchain implementation may specify standard C,
runtime, C++, etc libraries, as well as their link order.
Because a property approach is used, then Zephyr modules, such as the
Picolibc module can adjust such properties.
An optional `zephyr_linker_finalize()` macro is called at the end of
Zephyr's CMakeList process and can be used by the toolchain
implementation to define the final linker invocation.
This aligns the linker handling flow to the principle introduced in
PR#24851 and improves the flexibility and robustness of Zephyr build
system.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
Commit 282f77e732f0a4bc859f559bc5a748f953a8140c removed the only place
defining LIBC_INCLUDE_DIR. Remove the corresponding use of
LIBC_INCLUDE_DIR from newlib/CMakeLists.txt as this setting is no longer
being defined anywhere.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
It turns out that currently LTO is enabled only for the kernel.
This commit updates it to enable it for the whole application
and adds additional LTO exclusions required for the standard
C libraries to build and link properly.
Signed-off-by: Radosław Koppel <radoslaw.koppel@nordicsemi.no>
When Zephyr is compiled using LLVM toolchain, we don't need to link with
libgcc to resolve libc dependencies. With this patch, the trick will be
applied only when the GNU compiler is used. Otherwise, we will just link
libc, which works for LLVM.
Signed-off-by: Patryk Duda <pdk@semihalf.com>
This commit updates the Newlib integration to define `_ANSI_SOURCE`
in order to prevent Newlib from defining POSIX primitives in its
headers when GNU dialect is used (`-std=gnu*`).
Newlib `features.h` defines `_DEFAULT_SOURCE` when `__STRICT_ANSI__`
is not defined by GCC (i.e. when `-std=gnu*`), which results in the
Newlib headers defining POSIX primitives that are in conflict with the
POSIX primitives defined by Zephyr.
Newlib must not define POSIX primitives unless the feature test macros
such as `_POSIX_SOURCE`, `_GNU_SOURCE` and `_DEFAULT_SOURCE` are
explicitly defined.
Note that `-std=gnu` does not imply `_GNU_SOURCE` or `_DEFAULT_SOURCE`
because it is only supposed to instruct the compiler to use the GNU C
language dialect (i.e. GNU C language extensions).
Refer to the GitHub issue #52739 for more details.
Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
Fixes: #28650
Linking with newlib now defines the following linker flags as:
```
${CMAKE_C_LINKER_WRAPPER_FLAG}${CMAKE_LINK_LIBRARY_FLAG}c
${CMAKE_C_LINKER_WRAPPER_FLAG}${CMAKE_LINK_LIBRARY_FLAG}gcc
c
```
This is needed because when linking with newlib on aarch64, then libgcc
has a link dependency to libc (strchr), but libc also has dependencies
to libgcc.
CMake is capable of handling circular link dependencies for CMake
defined static libraries, which can be further controlled using
`LINK_INTERFACE_MULTIPLICITY`.
However, libc and libgcc are not regular CMake libraries, and is seen as
linker flags by CMake, and thus symbol de-duplications will be
performed.
CMake link options cannot be used, as that will place those libs first
on the linker invocation. -Wl,--start-group is problematic as the
placement of -lc and -lgcc is not guaranteed in case later libraries are
also using -lc / -libbgcc as interface linker flags.
Thus, we resort to use
`${CMAKE_C_LINKER_WRAPPER_FLAG}${CMAKE_LINK_LIBRARY_FLAG}`
as this ensures the uniqueness and thus avoids symbol de-duplication
which means libc will be followed by libgcc, which is finally followed
by libc again.
It would have been possible to use `-lc` directly, but there is a risk
that an externally library is also adding `-lc` and thus de-duplication
and re-arrangement of this flag happens. This risk is in theory also
existing with this fix, but the long nature of this link flag with using
`${CMAKE_C_LINKER_WRAPPER_FLAG}` would likely indicate a similar fix and
thus those libraries will stay in order.
Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
The solution from #14312 of using -isystem to prioritize the position of
the libc directory bypasses the effect of -ffreestanding with respect to
libc symbols expected to be present in a non-hosted environment.
Further, it breaks C++ with the ARM Embedded toolchain as the system
fails to find the right file with #include_next.
Use a more fine-grained solution that explicitly includes the underlying
newlib header required for <inttypes.h> support before moving on to
include the next available one, whether system or non-system.
Closes#17564
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Add an option for building with newlib-nano library.
The newlib-nano library for ARM embedded processors is a part of the
GNU Tools for ARM Embedded Processors.
Add mem_alloc tests with newlib nano.
Signed-off-by: Benoit Leforestier <benoit.leforestier@gmail.com>
Update the files which contain no license information with the
'Apache-2.0' SPDX license identifier. Many source files in the tree are
missing licensing information, which makes it harder for compliance
tools to determine the correct license.
By default all files without license information are under the default
license of Zephyr, which is Apache version 2.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
When we build with newlib we don't set -nostdinc. In that case make
sure that we leave it to the toolchain to set the system include paths.
The one exception to leaving to the toolchain to set the system include
paths is the path to the newlib headers. Since we build
with -ffreestanding we need to make sure the newlib header path is the
before the toolchain headers. Otherwise the toolchain's 'freestanding'
headers get picked up and that causes issues (for example getting PRI*64
defined properly from inttypes.h due to __STDC_HOSTED__ being '0').
For newlib we accomplish this by having the only system header specified
by zephyr_system_include_directories() being just the newlib headers.
Note: for minlibc we leave things alone as things just happen to work as
the -I include of the libc headers takes precedence over -isystem so we
get the libc headers over the toolchain ones. For the newlib case it
appears that setting both -I and -isystem for the same dir causes the
-I to be ignored.
Fixes#14310
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
We utilize defines like -ESHUTDOWN in the network stack. To support
this errno value with newlib we need to enable
__LINUX_ERRNO_EXTENSIONS__.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
We want to support other toolchain not based on GCC, so the variable is
confusing, use ZEPHYR_TOOLCHAIN_VARIANT instead.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
CROSS_COMPILE is a KBuild feature that was dropped during the CMake
migration. It is now re-introduced. Documentation for it is still
lacking, but at least it now behaves as expected.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
Introducing CMake is an important step in a larger effort to make
Zephyr easy to use for application developers working on different
platforms with different development environment needs.
Simplified, this change retains Kconfig as-is, and replaces all
Makefiles with CMakeLists.txt. The DSL-like Make language that KBuild
offers is replaced by a set of CMake extentions. These extentions have
either provided simple one-to-one translations of KBuild features or
introduced new concepts that replace KBuild concepts.
This is a breaking change for existing test infrastructure and build
scripts that are maintained out-of-tree. But for FW itself, no porting
should be necessary.
For users that just want to continue their work with minimal
disruption the following should suffice:
Install CMake 3.8.2+
Port any out-of-tree Makefiles to CMake.
Learn the absolute minimum about the new command line interface:
$ cd samples/hello_world
$ mkdir build && cd build
$ cmake -DBOARD=nrf52_pca10040 ..
$ cd build
$ make
PR: zephyrproject-rtos#4692
docs: http://docs.zephyrproject.org/getting_started/getting_started.html
Signed-off-by: Sebastian Boe <sebastian.boe@nordicsemi.no>
