The sorttable.c was a copy from recordmcount.c which is very hard to
maintain. That's because it uses macro helpers and places the code in a
header file sorttable.h to handle both the 64 bit and 32 bit version of
the Elf structures. It also uses _r()/r()/r2() wrappers around accessing
the data which will read the 64 bit or 32 bit version of the data as well
as handle endianess. If the wrong wrapper is used, an invalid value will
result, and this has been a cause for bugs in the past. In fact the new
ORC code doesn't even use it. That's fine because ORC is only for 64 bit
x86 which is the default parsing.
Instead of having a bunch of macros defined and then include the code
twice from a header, the Elf structures are each wrapped in a union. The
union holds the 64 bit and 32 bit version of the needed structure. Then
a structure of function pointers is used, along with helper macros
to access the ELF types appropriately for their byte size and endianess.
How to reference the data fields is moved from the code that implements
the sorting to the helper functions where all accesses to a field will
use he same helper function. As long as the helper functions access
the fields correctly, the code will also access the fields. This is
an improvement over having to code implementing the sorting having to
make sure it always uses the right accessor function when reading an
ELF field.
This is a clean up only, the functionality of the scripts/sorttable.c
does not change.
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Merge tag 'trace-sorttable-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull scipts/sorttable updates from Steven Rostedt:
"The sorttable.c was a copy from recordmcount.c which is very hard to
maintain. That's because it uses macro helpers and places the code in
a header file sorttable.h to handle both the 64 bit and 32 bit version
of the Elf structures. It also uses _r()/r()/r2() wrappers around
accessing the data which will read the 64 bit or 32 bit version of the
data as well as handle endianess. If the wrong wrapper is used, an
invalid value will result, and this has been a cause for bugs in the
past. In fact the new ORC code doesn't even use it. That's fine
because ORC is only for 64 bit x86 which is the default parsing.
Instead of having a bunch of macros defined and then include the code
twice from a header, the Elf structures are each wrapped in a union.
The union holds the 64 bit and 32 bit version of the needed structure.
Then a structure of function pointers is used, along with helper
macros to access the ELF types appropriately for their byte size and
endianess. How to reference the data fields is moved from the code
that implements the sorting to the helper functions where all accesses
to a field will use he same helper function. As long as the helper
functions access the fields correctly, the code will also access the
fields. This is an improvement over having to code implementing the
sorting having to make sure it always uses the right accessor function
when reading an ELF field.
This is a clean up only, the functionality of the scripts/sorttable.c
does not change"
* tag 'trace-sorttable-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
scripts/sorttable: Use a structure of function pointers for elf helpers
scripts/sorttable: Get start/stop_mcount_loc from ELF file directly
scripts/sorttable: Move code from sorttable.h into sorttable.c
scripts/sorttable: Use uint64_t for mcount sorting
scripts/sorttable: Add helper functions for Elf_Sym
scripts/sorttable: Add helper functions for Elf_Shdr
scripts/sorttable: Add helper functions for Elf_Ehdr
scripts/sorttable: Convert Elf_Sym MACRO over to a union
scripts/sorttable: Replace Elf_Shdr Macro with a union
scripts/sorttable: Convert Elf_Ehdr to union
scripts/sorttable: Make compare_extable() into two functions
scripts/sorttable: Have the ORC code use the _r() functions to read
scripts/sorttable: Remove unneeded Elf_Rel
scripts/sorttable: Remove unused write functions
scripts/sorttable: Remove unused macro defines
c0e75905ca