Re: [PATCH v3 14/20] perf riscv: Remove dwarf-regs.c and add dwarf-regs-table.h

Palmer Dabbelt
2024-10-18T19:46:23Z

On Wed, 16 Oct 2024 17:25:14 PDT (-0700), irogers@google.com wrote:
> The file just provides the function get_arch_regstr, however, if in
> the only caller get_dwarf_regstr EM_HOST is used for the EM_NONE case,
> and the register table is provided in a header file, the function can
> never be called. So remove as dead code. Tidy up the EM_NONE cases for
> riscv in dwarf-regs.c.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> .../dwarf-regs-table.h} | 32 ++++---------------
> tools/perf/arch/riscv/util/Build | 1 -
> tools/perf/util/dwarf-regs.c | 7 ++--
> tools/perf/util/include/dwarf-regs.h | 2 +-
> 4 files changed, 12 insertions(+), 30 deletions(-)
> rename tools/perf/arch/riscv/{util/dwarf-regs.c => include/dwarf-regs-table.h} (56%)
>
> diff --git a/tools/perf/arch/riscv/util/dwarf-regs.c b/tools/perf/arch/riscv/include/dwarf-regs-table.h
> similarity index 56%
> rename from tools/perf/arch/riscv/util/dwarf-regs.c
> rename to tools/perf/arch/riscv/include/dwarf-regs-table.h
> index a9c4402ae57e..a45b63a6d5a8 100644
> --- a/tools/perf/arch/riscv/util/dwarf-regs.c
> +++ b/tools/perf/arch/riscv/include/dwarf-regs-table.h
> @@ -1,23 +1,10 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd.
> - * Mapping of DWARF debug register numbers into register names.
> - */
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifdef DEFINE_DWARF_REGSTR_TABLE
> +/* This is included in perf/util/dwarf-regs.c */
>
> -#include <stddef.h>
> -#include <errno.h> /* for EINVAL */
> -#include <string.h> /* for strcmp */
> -#include <dwarf-regs.h>
> +#define REG_DWARFNUM_NAME(reg, idx) [idx] = "%" #reg
>
> -struct regs_dwarfnum {
> - const char *name;
> - unsigned int dwarfnum;
> -};
> -
> -#define REG_DWARFNUM_NAME(r, num) {.name = r, .dwarfnum = num}
> -#define REG_DWARFNUM_END {.name = NULL, .dwarfnum = 0}
> -
> -struct regs_dwarfnum riscv_dwarf_regs_table[] = {
> +static const char * const riscv_regstr_tbl[] = {
> REG_DWARFNUM_NAME("%zero", 0),
> REG_DWARFNUM_NAME("%ra", 1),
> REG_DWARFNUM_NAME("%sp", 2),
> @@ -50,13 +37,6 @@ struct regs_dwarfnum riscv_dwarf_regs_table[] = {
> REG_DWARFNUM_NAME("%t4", 29),
> REG_DWARFNUM_NAME("%t5", 30),
> REG_DWARFNUM_NAME("%t6", 31),
> - REG_DWARFNUM_END,
> };
>
> -#define RISCV_MAX_REGS ((sizeof(riscv_dwarf_regs_table) / \
> - sizeof(riscv_dwarf_regs_table[0])) - 1)
> -
> -const char *get_arch_regstr(unsigned int n)
> -{
> - return (n < RISCV_MAX_REGS) ? riscv_dwarf_regs_table[n].name : NULL;
> -}
> +#endif
> diff --git a/tools/perf/arch/riscv/util/Build b/tools/perf/arch/riscv/util/Build
> index 8f93091b8345..58a672246024 100644
> --- a/tools/perf/arch/riscv/util/Build
> +++ b/tools/perf/arch/riscv/util/Build
> @@ -2,5 +2,4 @@ perf-util-y += perf_regs.o
> perf-util-y += header.o
>
> perf-util-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
> -perf-util-$(CONFIG_LIBDW) += dwarf-regs.o
> perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
> diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
> index 3d98c2bf6035..2c6b197556dd 100644
> --- a/tools/perf/util/dwarf-regs.c
> +++ b/tools/perf/util/dwarf-regs.c
> @@ -20,6 +20,7 @@
> #include "../arch/arm64/include/dwarf-regs-table.h"
> #include "../arch/sh/include/dwarf-regs-table.h"
> #include "../arch/powerpc/include/dwarf-regs-table.h"
> +#include "../arch/riscv/include/dwarf-regs-table.h"
> #include "../arch/s390/include/dwarf-regs-table.h"
> #include "../arch/sparc/include/dwarf-regs-table.h"
> #include "../arch/xtensa/include/dwarf-regs-table.h"
> @@ -33,7 +34,7 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int
> {
> #if EM_HOST == EM_X86_64 || EM_HOST == EM_386 || EM_HOST == EM_AARCH64 || EM_HOST == EM_ARM \
> || EM_HOST == EM_CSKY || EM_HOST == EM_LOONGARCH || EM_HOST == EM_MIPS || EM_HOST == EM_PPC \
> - || EM_HOST == EM_PPC64
> + || EM_HOST == EM_PPC64 || EM_HOST == EM_RISCV
> if (machine == EM_NONE) {
> /* Generic arch - use host arch */
> machine = EM_HOST;
> @@ -42,7 +43,7 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int
> switch (machine) {
> #if EM_HOST != EM_X86_64 && EM_HOST != EM_386 && EM_HOST != EM_AARCH64 && EM_HOST != EM_ARM \
> && EM_HOST != EM_CSKY && EM_HOST != EM_LOONGARCH && EM_HOST != EM_MIPS && EM_HOST != EM_PPC \
> - && EM_HOST != EM_PPC64
> + && EM_HOST != EM_PPC64 && EM_HOST != EM_RISCV
> case EM_NONE: /* Generic arch - use host arch */
> return get_arch_regstr(n);
> #endif
> @@ -63,6 +64,8 @@ const char *get_dwarf_regstr(unsigned int n, unsigned int machine, unsigned int
> case EM_PPC:
> case EM_PPC64:
> return __get_dwarf_regstr(powerpc_regstr_tbl, n);
> + case EM_RISCV:
> + return __get_dwarf_regstr(riscv_regstr_tbl, n);
> case EM_SPARC:
> case EM_SPARCV9:
> return __get_dwarf_regstr(sparc_regstr_tbl, n);
> diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
> index 1763280855ce..35f4f33205da 100644
> --- a/tools/perf/util/include/dwarf-regs.h
> +++ b/tools/perf/util/include/dwarf-regs.h
> @@ -81,7 +81,7 @@
> #ifdef HAVE_LIBDW_SUPPORT
> #if !defined(__x86_64__) && !defined(__i386__) && !defined(__aarch64__) && !defined(__arm__) \
> && !defined(__loongarch__) && !defined(__mips__) && !defined(__powerpc__) \
> - && !defined(__powerpc64__)
> + && !defined(__powerpc64__) && !defined(__riscv__)
> const char *get_arch_regstr(unsigned int n);
> #endif

Acked-by: Palmer Dabbelt <palmer@rivosinc.com>