Commit Graph

145 Commits

Author SHA1 Message Date
Torsten Rasmussen
917d5021d7 cmake: CMake compile features support
Fixes: #36558 #32577

This commit introduces CMAKE_C_COMPILE_FEATURES and
CMAKE_CXX_COMPILE_FEATURES.

This allows users to use the `target_compile_features()` in their own
code.

In Zephyr, the CMAKE_C/CXX_COMPILE_FEATURES are defined based on the
compiler and the Kconfig / CSTD setting.
Doing so ensures that a user compiling Zephyr with c99 and specifies
`target_compile_features(<target> ... c_std_11)` will get an error.
And similar if building Zephyr with C++ support and c++11, but testing
for `target_compile_features(<target> ... cxx_std_17)`.

For example in the C++ case, the user must ensure that Zephyr is
compiled with C++17, that is: CPLUSPLUS=y and STD_CPP17=y, in which case
the CMAKE_CXX_COMPILE_FEATURES will contain support for C++17 and thus
the `target_compile_features(<target> ... cxx_std_17)` will succeed.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2021-10-01 14:40:33 -04:00
Stephanos Ioannidis
c2859bc7aa cmake: compiler: Add nostdincxx property for gcc
This commit adds the `nostdincxx` C++ compiler property for GCC, which
is specified when the C++ standard library (`CONFIG_LIB_CPLUSPLUS`) is
disabled.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-09-21 11:39:18 -04:00
Stephanos Ioannidis
fd4700d7b7 cmake: compiler: Add framework for disabling C++ standard includes
This commit adds a new C++ compiler property `nostdincxx` which
specifies the C++ compiler flag for excluding the C++ standard library
include directory from the include paths.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-09-21 11:39:18 -04:00
Andy Ross
0d763e0a10 cmake/compiler/xcc: sched: Support XCC inlining semantics
Cadence XCC is based off of a very old 4.2 gcc compiler, which didn't
perfectly support C99 "inline" semantics with respect to
cross-translation-unit inline linkage (which Zephyr does not use, our
inlines are static only) and declaration order.

Fix the one spot where we were calling an inline before its
ALWAYS_INLINE definition, and add a flag to suppress the warning so
CI's trying to build with XCC and -Werror don't flip out.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2021-09-08 09:28:31 -04:00
Jeremy Bettis
1fee4849bc cmake: Populate var CMAKE_GCOV
For each compiler, also set a CMAKE_GCOV var referencing the appropriate
gcov tool.

Tested with gcc and host-gcc on the ChromeOS codebase.

Signed-off-by: Jeremy Bettis <jbettis@chromium.org>
2021-09-02 19:44:00 -04:00
Stephanos Ioannidis
41fd6e003c arch: arm: aarch32: Add half-precision floating-point configs
This commit adds the half-precision (16-bit) floating-point
configurations to the ARM AArch32 architectures.

Enabling CONFIG_FP16 has the effect of specifying `-mfp16-format`
option (in case of GCC) which allows using the half-precision floating
point types such as `__fp16` and `_Float16`.

Note that this configuration can be used regardless of whether a
hardware FPU is available or supports half-precision operations.

When an FP16-capable FPU is not available, the compiler will
automatically provide the software emulations.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-08-30 18:17:47 +02:00
Torsten Rasmussen
36bb00d1f5 armclang: ARM Compiler C library support
Support for ARM Compiler C library.

This commit add support for the ARM Compiler C libary in:
- Kconfig
- libc/armstdc

A new Kconfig symbol is added to allow a toolchain to specify if they
support linking with the minimal C library.
Also the CMake variable `TOOLCHAIN_HAS_NEWLIB` is exported to Kconfig
so that CONFIG_NEWLIB_LIBS can only be enabled if the toolchain has
newlib.

The armclang toolchain selects the CMake scatter file generator and
disables support for the LD linker template which is not supported by
armlink.

For the ARM Compiler C library, a corresponding lib/libc/armstc/ folder
with a minimal implementation to work with the ARM Compiler C library
is added.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2021-08-30 08:54:23 -04:00
Torsten Rasmussen
40a2ffd2ea armclang: support for armclang compiler and armlink linker
This is the initial support for the armclang compiler together with the
armlink linker.

Introduced in this commit:
- armclang compiler support
- armlink linker support
- armlink scatter file generator for scatter loading
- dual pass linker script generation

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2021-08-30 08:54:23 -04:00
Evgeniy Paltsev
d8590d7e2b ARC: MWDT: fix include path for the case of C/C++ lib usage
Fix include path of headers provided by MWDT toolchain for the
case of MWDT C/C++ lib usage.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
2021-08-21 21:33:18 -04:00
Evgeniy Paltsev
b82ffbd860 ARC: MWDT: add C++14, C++17 standards support
Add missing properties for C++14, C++17 standards support

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
2021-08-21 21:33:18 -04:00
Stephanos Ioannidis
6df8f7e435 arch: arm: cortex_m: Add ARMv8.1-M MVE configs
This commit adds the ARMv8.1-M M-Profile Vector Extension (MVE)
configurations as well as the compiler flags to enable it.

The M-Profile Vector Extension consists of the MVE-I and MVE-F
instruction sets which are integer and floating-point vector
instruction sets, respectively.

The MVE-I instruction set is a superset of the ARM DSP instruction
set (ARMv7E-M) and therefore depends on ARMV8_M_DSP, and the MVE-F
instruction set is a superset of the ARM MVE-I instruction set and
therefore depends on ARMV8_1_M_MVEI.

The SoCs that implement the MVE instruction set should select the
following configurations:

  select ARMV8_M_DSP
  select ARMV8_1_M_MVEI
  select ARMV8_1_M_MVEF (if floating-point MVE is supported)

The GCC compiler flags for the MVE instruction set are specified
through the `-mcpu` flag.

In case of the Cortex-M55 (the only supported processor type for
ARMv8.1-M at the time of writing), the `-mcpu=cortex-m55` flag, by
default, enables all the supported extensions which are DSP, MVE-I and
MVE-F.

The extensions that are not supported can be specified by appending
`+no(ext)` to the `-mcpu=cortex-m55` flag:

  -mcpu=cortex-m55           Cortex-M55 with DSP + MVE-I + MVE-F
  -mcpu=cortex-m55+nomve.fp  Cortex-M55 with DSP + MVE-I
  -mcpu=cortex-m55+nomve     Cortex-M55 with DSP
  -mcpu=cortex-m55+nodsp     Cortex-M55 without any extensions

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-08-14 20:29:57 -04:00
Evgeniy Paltsev
33d5be8656 ARC: MWDT: generate access to builtin funcs only if ARCMWDT_LIBC is used
The MWDT compiler can replace some code with call to builtin
functions. We can't rely on these functions presence if we
don't use MWDT libc.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
2021-08-13 13:43:19 -05:00
Chen Peng1
98f324000c cmake: oneApi: add oneApi support on windows
The icx compiler of oneApi will invoke clang-cl on windows,
this is not supported in zephyr now, so change to use
clang directly.
And the clang from oneApi can't recognize those cross
compiling target variables of cmake, such as
CMAKE_C_COMPILER_TARGET, so used other cmake functions
to pass them to clang.

Signed-off-by: Chen Peng1 <peng1.chen@intel.com>
2021-07-27 07:20:12 -04:00
Daniel Leung
70d0077574 cmake: don't enable color diagnostics for xcc
The compiler option "-fdiagnostics-color=always" is not known to XCC
(which is based on really old GCC). So don't enable color
diagnostic output when building with XCC.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2021-07-22 15:41:11 +03:00
Alexander Wachter
ad130f2661 cpp: Restore C++2A Kconfig
Restore the legacy C++2a Kconfig for compilers that
do not support C++20.

Signed-off-by: Alexander Wachter <alexander.wachter@leica-geosystems.com>
2021-07-14 07:19:43 -04:00
Ioannis Glaropoulos
102fd5d41c arm: cortex-m: add FPU option for v8.M without DSP
With respect to the mapping between the CPU variant
and the FPU we add an entry for Cortex-M v8-M CPU
variants without DSP. This should cover the case
of a Mainline Cortex-M which implements the Floating
Point extension but not the DSP extension.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
2021-06-22 08:45:41 -04:00
Stephanos Ioannidis
733240378e cmake: host-gcc: Remove libgcc library path resolution
The host toolchain makes use of the host toolchain libraries (i.e.
`-nostdlib` is not specified), so it is not necessary to detect the
toolchain libgcc path and specify one manually.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-06-16 18:35:54 +02:00
Stephanos Ioannidis
ccda920c28 cmake: host-gcc: Detect libgcc for all archs
This commit updates the build system to always detect the libgcc path
for the host platforms regardless of the target architecture.

The native_posix_64 target previously used the x32 ABI (`-mx32`) and
the multilib for this ABI was not commonly available in the x86-64 host
toolchains.

That is no longer the case because native_posix_64 had been updated to
use the x86-64 ABI (`-m64`).

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-06-16 18:35:54 +02:00
Stephanos Ioannidis
010a95c2d0 cmake: gcc: Remove no_libgcc exclusion for libgcc detection
This commit removes the `NOT no_libgcc` condition for the automatic
libgcc path detection.

The `no_libgcc` variable was previously set in this file to exclude
libgcc detection for the x86-64 targets because the x86-64 arch used
x32 ABI (`-mx32`) and the multilib for this ABI was not commonly
available. This is no longer the case (x86-64 targets now use `-m64`)
and libgcc must always be available.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
2021-06-16 18:35:54 +02:00
Daniel Leung
72c2f182bc cmake: force GCC to emit DWARF version 4
GCC 11 defaults to output DWARF version 5 which pyelftools cannot
currently parse. So keep output at version 4 for the time being.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2021-06-04 16:22:03 -05:00
Lauren Murphy
e6b8c50599 samples: tensorflow: add no-threadsafe-statics to compiler flags
Adds no-threadsafe-statics to compiler flags for gcc and arcmwdt.

The flag is required to compile the samples - the module can compile
without it.

Signed-off-by: Lauren Murphy <lauren.murphy@intel.com>
2021-05-20 20:59:45 -04:00
Arvin Farahmand
b8f5968a42 cmake: gcc/clang: enable colour diagnostics in terminal output
When compiler results are piped through a non-terminal (e.g. ninja)
the compiler disables colour diagnostics. Using `-fdiagnostics-color`
forces the compiler to enable colour output. This flag is set for
clang and gcc when `ZEPHYR_BUILD_COLOUR_DIAGNOSTIC` environment
variable is set when a clean build is started.

Signed-off-by: Arvin Farahmand <arvinf@ip-logix.com>
2021-04-16 12:20:53 +02:00
Jaxson Han
72287491df cmake: arm64: Add Cortex-R82 in toolchain option
Use -march=armv8.4-a to compile zephyr on cortex-R82.
Because Cortex-R82 has not been enabled in GCC 10.x currently.

Signed-off-by: Jaxson Han <jaxson.han@arm.com>
2021-04-13 07:47:44 -04:00
Anas Nashif
11e44627e9 cmake: fix isystem_include_dir path for windows
The system include directory might include spaces on windows, so quote
it.

Partially part of fix for #32111

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2021-04-02 13:36:49 -04:00
Carlo Caione
3539c2fbb3 arm/arm64: Make ARM64 a standalone architecture
Split ARM and ARM64 architectures.

Details:

- CONFIG_ARM64 is decoupled from CONFIG_ARM (not a subset anymore)
- Arch and include AArch64 files are in a dedicated directory
  (arch/arm64 and include/arch/arm64)
- AArch64 boards and SoC are moved to soc/arm64 and boards/arm64
- AArch64-specific DTS files are moved to dts/arm64
- The A72 support for the bcm_vk/viper board is moved in the
  boards/bcm_vk/viper directory

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
2021-03-31 10:34:33 -05:00
Anas Nashif
1bb4e71bf2 toolchain: add support Intel oneApi toolchain based on llvm
This adds preliminary support for the oneApi toolchain for X86. The
toolchain is available from here:

   https://software.intel.com/content/www/us/en/develop/tools/oneapi/base-toolkit/download.html

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2021-03-25 08:54:10 -04:00
Anas Nashif
c7bc6380bd compiler: do not allow expansion-to-defined
'-Wexpansion-to-defined'
     Warn whenever 'defined' is encountered in the expansion of a macro
     (including the case where the macro is expanded by an '#if'
     directive).  Such usage is not portable.  This warning is also
     enabled by '-Wpedantic' and '-Wextra'.

This is enabled by default in llvm but not in gcc. Given that it is 'not
portable', lets disallow this in gcc and keep both compilers in sync.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2021-02-17 04:05:42 -05:00
Daniel Leung
ff720cd9b3 x86: enable soft float support for Zephyr SDK
This adds the correct compiler and linker flags to
support software floating point operations. The flags
need to be added to TOOLCHAIN_*_FLAGS for GCC to find
the correct library (when calling GCC with
--print-libgcc-file-name).

Note that software floating point needs to be turned
on for Newlib. This is due to Newlib having floating
point numbers in its various printf() functions which
results in floating point instructions being emitted
from toolchain. These instructions are placed very
early in the functions which results in them being
executed even though the format string contains
no floating point conversions. Without using CONFIG_FPU
to enable hardware floating point support, any calls to
printf() like functions will result in exceptions
complaining FPU is not available. Although forcing
CONFIG_FPU=y with newlib is an option, and because
the OS doesn't know which threads would call these
printf() functions, Zephyr has to assume all threads
are using FPU and thus incurring performance penalty as
every context switching now needs to save FPU registers.
A compromise here is to use soft float instead. Newlib
with soft float enabled does not have floating point
instructions and yet can still support its printf()
like functions.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2021-01-20 16:45:31 -05:00
Martin Åberg
0b7c89927c riscv: give -mcmodel=medany to GCC when linking
We compile objects with -mcmodel=medany. Now also give -mcmodel=medany
to the GCC front-end when linking to pick up the corresponding
multilibs.

Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
2021-01-15 13:06:33 -05:00
Shubham Kulkarni
a5ddb72261 boards: esp32: add 'nostdinc' expection for espressif toolchain
disable nostdinc for espressif tolchain

Signed-off-by: Shubham Kulkarni <shubham.kulkarni@espressif.com>
2021-01-13 09:10:46 -05:00
Peter Bigot
c7ad0b574a cmake: disable warning on C++ 20
Compound assigments like x |= y to volatile qualified values are
deprecated in C++20.  This idiom is common in CMSIS headers for
manipulating peripheral registers.  Since these headers are core they
are likely to be included indirectly in C++ modules; since they are in
vendor-provided headers we can't "fix" them.

Disable the warning when building for C++.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2020-12-19 04:54:46 -06:00
Martin Åberg
53a4acb2dc SPARC: add FPU support
This change adds full shared floating point support for the SPARC
architecture.

All SPARC floating point registers are scratch registers with respect
to function call boundaries. That means we only have to save floating
point registers when switching threads in ISR. The registers are
stored to the corresponding thread stack.

FPU is disabled when calling ISR. Any attempt to use FPU in ISR
will generate the fp_disabled trap which causes Zephyr fatal error.

- This commit adds no new thread state.
- All FPU contest save/restore is synchronous and lazy FPU context
  switch is not implemented.

Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
2020-12-04 14:33:43 +02:00
Martin Åberg
f8d1a9e5ea cmake: Added SPARC support
This commit defines the tool prefix and command line options for the
Zephyr SPARC architectural port.

Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
2020-11-13 14:53:55 -08:00
Daniel Leung
7d16ab50d7 cmake: fix xcc not supporting -Wno-unsed-but-set-variable
XCC does not support the compiler flag -Wno-unused-but-set-variable
so check for flag support before setting it in cmake.

Fixes #29707

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2020-11-10 21:51:36 -05:00
Anas Nashif
8f7f31b654 clang: do not assert on libgcc not found
We do not need libgcc always, some environments do not have libgcc and
do not require it, so keep it more flexible.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2020-11-02 14:30:37 -05:00
Anas Nashif
6e418c7022 clang: remove include-fixed inclusion
This directory does not exist in clang/llvm, remove it.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2020-11-02 14:30:37 -05:00
Anas Nashif
e6e29c0ccf toolchain: clang: add -Wno-typedef-redefinition option
Without the -Wno-typedef-redefinition option, clang complains if a
typedef gets redefined in gnu99  mode (since this is officially a C11
feature).

While new versions of GCC do not seem to issue this warning in gnu99
mode anymore. So some existing code with typedef redefined which works
well with GCC will issue this warning.

Similar to what was done in 2354f055ec.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2020-11-02 14:30:37 -05:00
Torsten Rasmussen
90f56dbabf cmake: extend target_ld_options() to support grouping of flags
Fixes #28456

This commit extends `target_ld_options()` with a NO_SPLIT flag.

Specifying `NO_SPLIT` will ensure that all linker flags will be applied
together when testing the compiler and linker.
This allows a caller to ensure that flags are tested together.

This fixes the RISC-V case where the flags `-mabi` and `-march` were
omitted because they were tested individually.

Note, the update of `target_ld_options()` will allow the same flag on
`zephyr_ld_options()`

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-10-27 13:09:02 +01:00
Watson Zeng
2354f055ec toolchain: arcmwdt: add compile options: -Wno-typedef-redefinition
Without the -Wno-typedef-redefinition option, arcmwdt (clang based)
complains if a typedef gets redefined in gnu99  mode (since this is
officially a C11 feature). While new versions of GCC do not seem to
issue this warning in gnu99 mode anymore. So some existing code
with typedef redefined which works well with GCC will issue this
warning. As this warning is not fatal, so simply shut it off for good.

Signed-off-by: Watson Zeng <zhiwei@synopsys.com>
2020-10-19 14:06:07 -05:00
Eugeniy Paltsev
9b0ef4f19a ARC: MWDT: drop redundant stack checking
MWDT toolchain has Stackcheck_alloca option enabled by default.
So it adds stack checking in addition to Zephyr's stack checking.

As it is completely redundant let's drop it.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
2020-10-02 11:32:12 +02:00
Torsten Rasmussen
27e1fd69f9 cmake: c++ compiler flag exclusion, -Werror=implicit-int
Fixes: #28097

The compiler warning flag `-Werror=implicit-int` was added using
`set_compiler_property()` which will always add the compiler flag if the
compiler flag supports it.

This has been changed to `check_set_compiler_property()` which will
check if the flag is among the list of `CXX_EXCLUDED_OPTIONS`, and only
adds the flag if both the compiler supports it, and it is not an
excluded option.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-09-07 17:22:37 +02:00
Torsten Rasmussen
93e063ffc8 cmake: mwdt compiler adopted to new toolchain abstraction
This commit converts the MWDT compiler implementation from the old
macro based approach and into the new toolchain property scheme.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-09-05 10:22:56 -05:00
Eugeniy Paltsev
6dfaac0c95 cmake: allow to specify compliler for DTS preprocessing
MWDT CCAC compiler can't handle the dts file as gcc does, so
allow to specify compliler for DTS preprocessing which is differ
from ${CMAKE_C_COMPILER}.

Use ARC GNU compiler for DTS preprocessing in case of MWDT
toolchain.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
2020-09-05 10:22:56 -05:00
Wayne Ren
b868018b51 cmake: add metaware toolchain support in build system
* add metaware toolchain support in build system:
   * compiler
   * linker
   * binutils
     * gcc objcopy is used because it can't be replaced
       with mwdt's binutils currently
* To use ARC metaware toolchain, you'd better:
   * in Linux/Unix environment
   * install arc gcc/zephyr toolchain to use gnu's objcopy
     tool
   * set ZEPHYR_TOOLCHAIN_VARIANT=arcmwdt

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
Signed-off-by: Watson Zeng <zhiwei@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
2020-09-05 10:22:56 -05:00
Torsten Rasmussen
73117e7cad toolchain: Xtensa C compiler using new abstraction pattern
The Xtense xcc compiler now uses the new compiler abstraction.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-09-04 20:36:59 +02:00
Torsten Rasmussen
31a1411cbd cmake: toolchain: Toolchain abstraction templates
As part of toolchain abstraction three template files to facilitate
additional toolchain support development has been introduced.

Those covers:
- bintools
- compiler flags
- linker flags

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-09-04 20:36:59 +02:00
Torsten Rasmussen
c55c64e242 toolchain: improved toolchain abstraction for compilers and linker
First abstraction completed for the toolchains:
- gcc
- clang

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-09-04 20:36:59 +02:00
Rihards Skuja
38e1bf1f29 cmake: toolchain: fix unsupported warnings for C++ builds
Compile with arm-none-eabi-g++ (10.2.0 with -std=c++17) generates a
warning for every C++ source file:
"cc1plus: warning: command-line option '-Wno-pointer-sign' is valid for
C/ObjC but not for C++"

Get rid of those warnings by adding '-Wno-pointer-sign' to the list of
excluded CXX options.

Signed-off-by: Rihards Skuja <rihardssk@mikrotik.com>
2020-09-03 21:47:14 +02:00
Flavio Ceolin
438adb0109 coding_guideline: Add optional flag to check override initialization
This enforce Rule 9.4

"""
An element of an object shall not be initialized more than once
"""

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2020-08-28 16:50:39 -04:00
Flavio Ceolin
d34c44d724 coding_guideline: Add optional flag to check invalid conversions
Generate errors for implicit conversions that may alter a value, that
covers conversions implicit conversions to narrower types, different
signal, different essential types (float -> int), ... From GCC
documentation
(https://gcc.gnu.org/onlinedocs/gcc-9.3.0/gcc/Warning-Options.html)

"""
Warn for implicit conversions that may alter a value. This includes
conversions between real and integer, like abs (x) when x is double;
conversions between signed and unsigned, like unsigned ui = -1; and
conversions to smaller types, like sqrtf (M_PI). Do not warn for
explicit casts like abs ((int) x) and ui = (unsigned) -1, or if the
value is not changed by the conversion like in abs (2.0). Warnings
about conversions between signed and unsigned integers can be disabled
by using -Wno-sign-conversion.

For C++, also warn for confusing overload resolution for user-defined
conversions; and conversions that never use a type conversion
operator: conversions to void, the same type, a base class or a
reference to them. Warnings about conversions between signed and
unsigned integers are disabled by default in C++ unless
-Wsign-conversion is explicitly enabled.
"""

This partially cover rules: 10.4, 10.5, 10.6, 10.7 and 10.8

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2020-08-28 16:50:39 -04:00