Similar to ARM/AARCH64, we add mapping symbols in the symbol table,
to mark the start addresses of data and instructions. The $d means
data, and the $x means instruction. Then the disassembler uses these
symbols to decide whether we should dump data or instruction.
Consider the mapping-04 test case,
$ cat tmp.s
.text
.option norelax
.option norvc
.fill 2, 4, 0x1001
.byte 1
.word 0
.balign 8
add a0, a0, a0
.fill 5, 2, 0x2002
add a1, a1, a1
.data
.word 0x1 # No need to add mapping symbols.
.word 0x2
$ riscv64-unknown-elf-as tmp.s -o tmp.o
$ riscv64-unknown-elf-objdump -d tmp.o
Disassembly of section .text:
0000000000000000 <.text>:
0: 00001001 .word 0x00001001 # Marked $d, .fill directive.
4: 00001001 .word 0x00001001
8: 00000001 .word 0x00000001 # .byte + part of .word.
c: 00 .byte 0x00 # remaining .word.
d: 00 .byte 0x00 # Marked $d, odd byte of alignment.
e: 0001 nop # Marked $x, nops for alignment.
10: 00a50533 add a0,a0,a0
14: 20022002 .word 0x20022002 # Marked $d, .fill directive.
18: 20022002 .word 0x20022002
1c: 2002 .short 0x2002
1e: 00b585b3 add a1,a1,a1 # Marked $x.
22: 0001 nop # Section tail alignment.
24: 00000013 nop
* Use $d and $x to mark the distribution of data and instructions.
Alignments of code are recognized as instructions, since we usually
fill nops for them.
* If the alignment have odd bytes, then we cannot just fill the nops
into the spaces. We always fill an odd byte 0x00 at the start of
the spaces. Therefore, add a $d mapping symbol for the odd byte,
to tell disassembler that it isn't an instruction. The behavior
is same as Arm and Aarch64.
The elf/linux toolchain regressions all passed. Besides, I also
disable the mapping symbols internally, but use the new objudmp, the
regressions passed, too. Therefore, the new objudmp should dump
the objects corretly, even if they don't have any mapping symbols.
bfd/
pr 27916
* cpu-riscv.c (riscv_elf_is_mapping_symbols): Define mapping symbols.
* cpu-riscv.h: extern riscv_elf_is_mapping_symbols.
* elfnn-riscv.c (riscv_maybe_function_sym): Do not choose mapping
symbols as a function name.
(riscv_elf_is_target_special_symbol): Add mapping symbols.
binutils/
pr 27916
* testsuite/binutils-all/readelf.s: Updated.
* testsuite/binutils-all/readelf.s-64: Likewise.
* testsuite/binutils-all/readelf.s-64-unused: Likewise.
* testsuite/binutils-all/readelf.ss: Likewise.
* testsuite/binutils-all/readelf.ss-64: Likewise.
* testsuite/binutils-all/readelf.ss-64-unused: Likewise.
gas/
pr 27916
* config/tc-riscv.c (make_mapping_symbol): Create a new mapping symbol.
(riscv_mapping_state): Decide whether to create mapping symbol for
frag_now. Only add the mapping symbols to text sections.
(riscv_add_odd_padding_symbol): Add the mapping symbols for the
riscv_handle_align, which have odd bytes spaces.
(riscv_check_mapping_symbols): Remove any excess mapping symbols.
(md_assemble): Marked as MAP_INSN.
(riscv_frag_align_code): Marked as MAP_INSN.
(riscv_init_frag): Add mapping symbols for frag, it usually called
by frag_var. Marked as MAP_DATA for rs_align and rs_fill, and
marked as MAP_INSN for rs_align_code.
(s_riscv_insn): Marked as MAP_INSN.
(riscv_adjust_symtab): Call riscv_check_mapping_symbols.
* config/tc-riscv.h (md_cons_align): Defined to riscv_mapping_state
with MAP_DATA.
(TC_SEGMENT_INFO_TYPE): Record mapping state for each segment.
(TC_FRAG_TYPE): Record the first and last mapping symbols for the
fragments. The first mapping symbol must be placed at the start
of the fragment.
(TC_FRAG_INIT): Defined to riscv_init_frag.
* testsuite/gas/riscv/mapping-01.s: New testcase.
* testsuite/gas/riscv/mapping-01a.d: Likewise.
* testsuite/gas/riscv/mapping-01b.d: Likewise.
* testsuite/gas/riscv/mapping-02.s: Likewise.
* testsuite/gas/riscv/mapping-02a.d: Likewise.
* testsuite/gas/riscv/mapping-02b.d: Likewise.
* testsuite/gas/riscv/mapping-03.s: Likewise.
* testsuite/gas/riscv/mapping-03a.d: Likewise.
* testsuite/gas/riscv/mapping-03b.d: Likewise.
* testsuite/gas/riscv/mapping-04.s: Likewise.
* testsuite/gas/riscv/mapping-04a.d: Likewise.
* testsuite/gas/riscv/mapping-04b.d: Likewise.
* testsuite/gas/riscv/mapping-norelax-04a.d: Likewise.
* testsuite/gas/riscv/mapping-norelax-04b.d: Likewise.
* testsuite/gas/riscv/no-relax-align.d: Updated.
* testsuite/gas/riscv/no-relax-align-2.d: Likewise.
include/
pr 27916
* opcode/riscv.h (enum riscv_seg_mstate): Added.
opcodes/
pr 27916
* riscv-dis.c (last_map_symbol, last_stop_offset, last_map_state):
Added to dump sections with mapping symbols.
(riscv_get_map_state): Get the mapping state from the symbol.
(riscv_search_mapping_symbol): Check the sorted symbol table, and
then find the suitable mapping symbol.
(riscv_data_length): Decide which data size we should print.
(riscv_disassemble_data): Dump the data contents.
(print_insn_riscv): Handle the mapping symbols.
(riscv_symbol_is_valid): Marked mapping symbols as invalid.
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