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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.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.