This patch adds support for building release images. The main difference
between release images and default images is that the former is optimized
for size while the latter is "optimized" for debugging. To build a release
image, the BUILD_RELEASE variable should be set to 1. For instance, the
following command build a release image from the hello-world application:
$ cd examples/hello-world && make TARGET=galileo BUILD_RELEASE=1
To optimize for size we use the '-Os' option from gcc. This option also
enables the strict aliasing optimization. This generates lots of warning
messages since we use the '-Wall' option and lots of code in core/net/
break the strict-aliasing rules. Some test have shown that the strict
aliasing optimization it not taking effect in the final binary. For that
reasons, this patch manually disables the optimization. Also, the release
image is stripped.
For the sake of comparison, below follows the output from 'wc' and 'size'
for both debugging (default) and release images.
Default image:
$ wc -c hello-world.galileo
71112 hello-world.galileo
$ size hello-world.galileo
text data bss dec hex filename
20379 1188 12808 34375 8647 hello-world.galileo
Release image:
$ wc -c hello-world.galileo
26320 hello-world.galileo
$ size hello-world.galileo
text data bss dec hex filename
18146 1156 12808 32110 7d6e hello-world.galileo
This patch does several cleanups in Makefile.x86_common file. The
changes are described above.
1) The CFLAGNO variable was removed since it is used only to assign
the CFLAGS variable. Also, CFLAGNO is not used outside Makefile.x86_
common.
2) The "-I/usr/local/include" option was removed since we provide manually
the include path from newlib in the bsp/ directory.
3) We only support building x86-based platforms on Linux so there is no
point in setting LDFLAGS conditionally.
4) The '-export-dynamic' option was removed from LDFLAGS since we are not
creating a dynamically linked executable.
5) Makefile.x86_quarkX1000 is the only one that includes Makefile.x86_
common. Since it doesn't use the custom rules from Makefile.x86_
common we remove them.
This patch adds "--build-id=none" to default LDFLAGS so
.note.gnu.build-id section is not generated. This section
contains unique identification for the built files what is
not important to us (at least at this moment).
This change simplifies all linker scripts for SoCs based on x86
(at this moment we only have Quark X1000) since we don't have to
care about it anymore.
The x86/init/common/ folder holds all cpu initialization
code - idt and gdt setup, interrupts and cpu initialization.
On this folder will also sit any SoC specific implementation of
the functions called from cpu_init().
Now the cpu/x86/ provides a Makefile.x86_common and a
Makefile.x86_pc. The former includes the common Makefile
and adds legacy pc specific implementations (currently,
drivers only) into the building context, while the latter
has everything that defines the bootstrap of a x86 CPU.
This commit also fixes platform/galileo/ so it includes the
correct makefile - Makefile.x86_quarkX1000. Galileo uses
a Quark X1000 SoC which is not an IBM Generic PC-like CPU,
but it does provide most of a PCs peripherals through
its "Legacy Bridge". Thus, it makes sense that QuarkX1000's
Makefile includes code from the legacy_pc x86 cpu.
