Re: [PATCH v2 19/31] perf arm64: Remove dwarf-regs.c

[Google]

On Sat,  5 Oct 2024 12:55:29 -0700
Ian Rogers <irogers@xxxxxxxxxx> 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
> the function can never be called. So remove as dead code. Tidy up the
> EM_NONE cases for arm64 in dwarf-regs.c.

OK, this seems just a redundant information in 
tools/perf/arch/arm64/include/dwarf-regs-table.h (there is alredy
register number -> name mapping table.)

Looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thank you,

> 
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
>  tools/perf/arch/arm64/util/Build        |  1 -
>  tools/perf/arch/arm64/util/dwarf-regs.c | 80 -------------------------
>  tools/perf/util/dwarf-regs.c            |  4 +-
>  tools/perf/util/include/dwarf-regs.h    |  2 +-
>  4 files changed, 3 insertions(+), 84 deletions(-)
>  delete mode 100644 tools/perf/arch/arm64/util/dwarf-regs.c
> 
> diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
> index 4387a6d6a6c3..a74521b79eaa 100644
> --- a/tools/perf/arch/arm64/util/Build
> +++ b/tools/perf/arch/arm64/util/Build
> @@ -4,7 +4,6 @@ perf-util-y += perf_regs.o
>  perf-util-y += tsc.o
>  perf-util-y += pmu.o
>  perf-util-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
> -perf-util-$(CONFIG_LIBDW)     += dwarf-regs.o
>  perf-util-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
>  perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
>  
> diff --git a/tools/perf/arch/arm64/util/dwarf-regs.c b/tools/perf/arch/arm64/util/dwarf-regs.c
> deleted file mode 100644
> index 343a62fa4199..000000000000
> --- a/tools/perf/arch/arm64/util/dwarf-regs.c
> +++ /dev/null
> @@ -1,80 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Mapping of DWARF debug register numbers into register names.
> - *
> - * Copyright (C) 2010 Will Deacon, ARM Ltd.
> - */
> -
> -#include <errno.h>
> -#include <stddef.h>
> -#include <string.h>
> -#include <dwarf-regs.h>
> -#include <linux/stringify.h>
> -
> -struct regs_dwarfnum {
> -	const char *name;
> -	unsigned int dwarfnum;
> -};
> -
> -#define REG_DWARFNUM_NAME(r, num) {.name = r, .dwarfnum = num}
> -#define GPR_DWARFNUM_NAME(num) \
> -	{.name = __stringify(%x##num), .dwarfnum = num}
> -#define REG_DWARFNUM_END {.name = NULL, .dwarfnum = 0}
> -
> -/*
> - * Reference:
> - * http://infocenter.arm.com/help/topic/com.arm.doc.ihi0057b/IHI0057B_aadwarf64.pdf
> - */
> -static const struct regs_dwarfnum regdwarfnum_table[] = {
> -	GPR_DWARFNUM_NAME(0),
> -	GPR_DWARFNUM_NAME(1),
> -	GPR_DWARFNUM_NAME(2),
> -	GPR_DWARFNUM_NAME(3),
> -	GPR_DWARFNUM_NAME(4),
> -	GPR_DWARFNUM_NAME(5),
> -	GPR_DWARFNUM_NAME(6),
> -	GPR_DWARFNUM_NAME(7),
> -	GPR_DWARFNUM_NAME(8),
> -	GPR_DWARFNUM_NAME(9),
> -	GPR_DWARFNUM_NAME(10),
> -	GPR_DWARFNUM_NAME(11),
> -	GPR_DWARFNUM_NAME(12),
> -	GPR_DWARFNUM_NAME(13),
> -	GPR_DWARFNUM_NAME(14),
> -	GPR_DWARFNUM_NAME(15),
> -	GPR_DWARFNUM_NAME(16),
> -	GPR_DWARFNUM_NAME(17),
> -	GPR_DWARFNUM_NAME(18),
> -	GPR_DWARFNUM_NAME(19),
> -	GPR_DWARFNUM_NAME(20),
> -	GPR_DWARFNUM_NAME(21),
> -	GPR_DWARFNUM_NAME(22),
> -	GPR_DWARFNUM_NAME(23),
> -	GPR_DWARFNUM_NAME(24),
> -	GPR_DWARFNUM_NAME(25),
> -	GPR_DWARFNUM_NAME(26),
> -	GPR_DWARFNUM_NAME(27),
> -	GPR_DWARFNUM_NAME(28),
> -	GPR_DWARFNUM_NAME(29),
> -	REG_DWARFNUM_NAME("%lr", 30),
> -	REG_DWARFNUM_NAME("%sp", 31),
> -	REG_DWARFNUM_END,
> -};
> -
> -/**
> - * get_arch_regstr() - lookup register name from it's DWARF register number
> - * @n:	the DWARF register number
> - *
> - * get_arch_regstr() returns the name of the register in struct
> - * regdwarfnum_table from it's DWARF register number. If the register is not
> - * found in the table, this returns NULL;
> - */
> -const char *get_arch_regstr(unsigned int n)
> -{
> -	const struct regs_dwarfnum *roff;
> -
> -	for (roff = regdwarfnum_table; roff->name != NULL; roff++)
> -		if (roff->dwarfnum == n)
> -			return roff->name;
> -	return NULL;
> -}
> diff --git a/tools/perf/util/dwarf-regs.c b/tools/perf/util/dwarf-regs.c
> index eac99a246737..18e916c8e993 100644
> --- a/tools/perf/util/dwarf-regs.c
> +++ b/tools/perf/util/dwarf-regs.c
> @@ -32,14 +32,14 @@
>  const char *get_dwarf_regstr(unsigned int n, unsigned int machine,
>  			     unsigned int flags __maybe_unused)
>  {
> -#if EM_HOST == EM_X86_64 || EM_HOST == EM_386
> +#if EM_HOST == EM_X86_64 || EM_HOST == EM_386 || EM_HOST == EM_AARCH64
>  	if (machine == EM_NONE) {
>  		/* Generic arch - use host arch */
>  		machine = EM_HOST;
>  	}
>  #endif
>  	switch (machine) {
> -#if EM_HOST != EM_X86_64 && EM_HOST != EM_386
> +#if EM_HOST != EM_X86_64 && EM_HOST != EM_386 && EM_HOST != EM_AARCH64
>  	case EM_NONE:	/* Generic arch - use host arch */
>  		return get_arch_regstr(n);
>  #endif
> diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
> index 062623aefd5a..e640657f69c8 100644
> --- a/tools/perf/util/include/dwarf-regs.h
> +++ b/tools/perf/util/include/dwarf-regs.h
> @@ -79,7 +79,7 @@
>  #define DWARF_REG_FB  0xd3affb /* random number */
>  
>  #ifdef HAVE_LIBDW_SUPPORT
> -#if !defined(__x86_64__) && !defined(__i386__)
> +#if !defined(__x86_64__) && !defined(__i386__) && !defined(__aarch64__)
>  const char *get_arch_regstr(unsigned int n);
>  #endif
>  
> -- 
> 2.47.0.rc0.187.ge670bccf7e-goog
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>