BTF does not carry alignment information, but it carries the offset in
structs. This allows inferring the original alignment, yielding a C
header dump that is not identical to the original C code, but is
guaranteed to lead to the same memory layout.
This allows using the output of pahole in another program to poke at
memory, with the assurance that we will not read garbage.
Note: Since the alignment is inferred from the offset, it sometimes
happens that the offset was already correctly aligned, which means the
inferred alignment will be smaller than in the original source. This
does not impact the ability to read existing structs, but it could
impact creating such struct if other client code expects higher
alignment than the one exposed in the generated header.
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Cc: dwarves@vger.kernel.org
[ Split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Build instructions:
1. install cmake
2. mkdir build
3. cd build
4. cmake -D__LIB=lib ..
5. make install
cmake Options:
-DBUILD_SHARED_LIBS
By default SHARED libraries are created and applications are linked to it.
Use -DBUILD_SHARED_LIBS=OFF while invoking cmake to create STATIC libraries
and link applications to it.
Ex. cmake -D__LIB=lib -DBUILD_SHARED_LIBS=OFF ..
-DCMAKE_INSTALL_PREFIX
Default is to install to /usr/local, use -DCMAKE_INSTALL_PREFIX=
when invoking cmake to specify another install location.
Known to work scenarios:
Mandriva Cooker:
cmake 2.4.5-1mdv2007.1
libelfutils1-devel 0.123-1mdv2007.1
Debian Unstable:
cmake 2.4.5-1
libdw-dev 0.123-2
Fedora Core 6:
cmake 2.4.5-2.fc6
elfutils-devel 0.126-1.fc6
836c139fdf