diff options
author | Jose E. Marchesi <jose.marchesi@oracle.com> | 2023-07-15 00:50:14 +0200 |
---|---|---|
committer | Jose E. Marchesi <jose.marchesi@oracle.com> | 2023-07-21 12:20:40 +0200 |
commit | d218e7fedc74d67837d2134120917f4ac877454c (patch) | |
tree | df890450897d7540385d9d7b5926ab35cbafb120 /opcodes/disassemble.c | |
parent | 1c850ca80dc53ffa2bfadabbacda231c941dee76 (diff) | |
download | gdb-d218e7fedc74d67837d2134120917f4ac877454c.zip gdb-d218e7fedc74d67837d2134120917f4ac877454c.tar.gz gdb-d218e7fedc74d67837d2134120917f4ac877454c.tar.bz2 |
DesCGENization of the BPF binutils port
CGEN is cool, but the BPF architecture is simply too bizarre for it.
The weird way of BPF to handle endianness in instruction encoding, the
weird C-like alternative assembly syntax, the weird abuse of
multi-byte (or infra-byte) instruction fields as opcodes, the unusual
presence of opcodes beyond the first 32-bits of some instructions, are
all examples of what makes it a PITA to continue using CGEN for this
port. The bpf.cpu file is becoming so complex and so nested with
p-macros that it is very difficult to read, and quite challenging to
update. Also, every time we are forced to change something in CGEN to
accommodate BPF requirements (which is often) we have to do extensive
testing to make sure we do not break any other target using CGEN.
This is getting un-maintenable.
So I have decided to bite the bullet and revamp/rewrite the port so it
no longer uses CGEN. Overall, this involved:
* To remove the cpu/bpf.{cpu,opc} descriptions.
* To remove the CGEN generated files.
* To replace the CGEN generated opcodes table with a new hand-written
opcodes table for BPF.
* To replace the CGEN generated disassembler wih a new disassembler
that uses the new opcodes.
* To replace the CGEN generated assembler with a new assembler that uses the
new opcodes.
* To replace the CGEN generated simulator with a new simulator that uses the
new opcodes. [This is pushed in GDB in another patch.]
* To adapt the build systems to the new situation.
Additionally, this patch introduces some extensions and improvements:
* A new BPF relocation BPF_RELOC_BPF_DISP16 plus corresponding ELF
relocation R_BPF_GNU_64_16 are added to the BPF BFD port. These
relocations are used for section-relative 16-bit offsets used in
load/store instructions.
* The disassembler now has support for the "pseudo-c" assembly syntax of
BPF. What dialect to use when disassembling is controlled by a command
line option.
* The disassembler now has support for dumping instruction immediates in
either octal, hexadecimal or decimal. The used output base is controlled
by a new command-line option.
* The GAS BPF test suite has been re-structured and expanded in order to
test the disassembler pseudoc syntax support. Minor bugs have been also
fixed there. The assembler generic tests that were disabled for bpf-*-*
targets due to the previous implementation of pseudoc syntax are now
re-enabled. Additional tests have been added to test the new features of
the assembler. .dump files are no longer used.
* The linker BPF test suite has been adapted to the command line options
used by the new disassembler.
The result is very satisfactory. This patchs adds 3448 lines of code
and removes 10542 lines of code.
Tested in:
* Target bpf-unknown-none with 64-bit little-endian host and 32-bit
little-endian host.
* Target x86-64-linux-gnu with --enable-targets=all
Note that I have not tested in a big-endian host yet. I will do so
once this lands upstream so I can use the GCC compiler farm.
I have not included ChangeLog entries in this patch: these would be
massive and not very useful, considering this is pretty much a rewrite
of the port. I beg the indulgence of the global maintainers.
Diffstat (limited to 'opcodes/disassemble.c')
-rw-r--r-- | opcodes/disassemble.c | 30 |
1 files changed, 8 insertions, 22 deletions
diff --git a/opcodes/disassemble.c b/opcodes/disassemble.c index 7a4a641..a5cb396 100644 --- a/opcodes/disassemble.c +++ b/opcodes/disassemble.c @@ -108,23 +108,6 @@ #include "m32c-desc.h" #endif -#ifdef ARCH_bpf -/* XXX this should be including bpf-desc.h instead of this hackery, - but at the moment it is not possible to include several CGEN - generated *-desc.h files simultaneously. To be fixed in - CGEN... */ - -# ifdef ARCH_m32c -enum epbf_isa_attr -{ - ISA_EBPFLE, ISA_EBPFBE, ISA_XBPFLE, ISA_XBPFBE, ISA_EBPFMAX -}; -# else -# include "bpf-desc.h" -# define ISA_EBPFMAX ISA_MAX -# endif -#endif /* ARCH_bpf */ - disassembler_ftype disassembler (enum bfd_architecture a, bool big ATTRIBUTE_UNUSED, @@ -594,7 +577,9 @@ disassembler_usage (FILE *stream ATTRIBUTE_UNUSED) #ifdef ARCH_loongarch print_loongarch_disassembler_options (stream); #endif - +#ifdef ARCH_bpf + print_bpf_disassembler_options (stream); +#endif return; } @@ -695,6 +680,9 @@ disassemble_init_for_target (struct disassemble_info * info) #endif #ifdef ARCH_bpf case bfd_arch_bpf: + /* XXX option for dialect */ + info->created_styled_output = true; +#if 0 info->endian_code = BFD_ENDIAN_LITTLE; if (!info->private_data) { @@ -712,6 +700,7 @@ disassemble_init_for_target (struct disassemble_info * info) cgen_bitset_set (info->private_data, ISA_XBPFLE); } } +#endif break; #endif #ifdef ARCH_pru @@ -768,13 +757,10 @@ disassemble_free_target (struct disassemble_info *info) default: return; -#ifdef ARCH_bpf - case bfd_arch_bpf: -#endif #ifdef ARCH_m32c case bfd_arch_m32c: #endif -#if defined ARCH_bpf || defined ARCH_m32c +#if defined ARCH_m32c if (info->private_data) { CGEN_BITSET *mask = info->private_data; |