Re: [Qemu-devel] [RFC 4/4] disas: implement host disassembly output for aarch64

[Andreas Färber]

Am 11.09.2013 15:08, schrieb Claudio Fontana:
> use C++ libvixl to implement output, for now only enabled for the host output
> disasm, since we don't have the aarch64 target yet.
> 
> Signed-off-by: Claudio Fontana <address@hidden>
> ---
>  configure                   |  6 +++++
>  disas.c                     |  2 ++
>  disas/Makefile.objs         |  7 ++++++
>  disas/aarch64-cxx.cc        | 53 
> +++++++++++++++++++++++++++++++++++++++++++++
>  disas/aarch64.c             | 45 ++++++++++++++++++++++++++++++++++++++
>  disas/libvixl/Makefile.objs |  6 +++++
>  include/disas/bfd.h         |  1 +
>  7 files changed, 120 insertions(+)
>  create mode 100644 disas/aarch64-cxx.cc
>  create mode 100644 disas/aarch64.c
>  create mode 100644 disas/libvixl/Makefile.objs
> 
> diff --git a/configure b/configure
> index 6b73d99..1a2648a 100755
> --- a/configure
> +++ b/configure
> @@ -4443,6 +4443,12 @@ ldflags=""
>  
>  for i in $ARCH $TARGET_BASE_ARCH ; do
>    case "$i" in
> +  aarch64)
> +    if test "x${cxx}" != "x"; then
> +      echo "CONFIG_AARCH64_DIS=y"  >> $config_target_mak
> +      echo "CONFIG_AARCH64_DIS=y"  >> config-all-disas.mak
> +    fi
> +  ;;
>    alpha)
>      echo "CONFIG_ALPHA_DIS=y"  >> $config_target_mak
>      echo "CONFIG_ALPHA_DIS=y"  >> config-all-disas.mak
> diff --git a/disas.c b/disas.c
> index 0203ef2..cc20c4a 100644
> --- a/disas.c
> +++ b/disas.c
> @@ -356,6 +356,8 @@ void disas(FILE *out, void *code, unsigned long size)
>  #elif defined(_ARCH_PPC)
>      s.info.disassembler_options = (char *)"any";
>      print_insn = print_insn_ppc;
> +#elif defined(__aarch64__)
> +    print_insn = print_insn_aarch64;
>  #elif defined(__alpha__)
>      print_insn = print_insn_alpha;
>  #elif defined(__sparc__)
> diff --git a/disas/Makefile.objs b/disas/Makefile.objs
> index 3b1e77a..f468c22 100644
> --- a/disas/Makefile.objs
> +++ b/disas/Makefile.objs
> @@ -1,3 +1,10 @@
> +ifeq ($(CONFIG_AARCH64_DIS),y)
> +libvixldir = $(SRC_PATH)/disas/libvixl/src
> +QEMU_CFLAGS += -I$(libvixldir) -Wno-undef
> +common-obj-$(CONFIG_AARCH64_DIS) += libvixl/
> +common-obj-$(CONFIG_AARCH64_DIS) += aarch64.o aarch64-cxx.o
> +endif
> +
>  common-obj-$(CONFIG_ALPHA_DIS) += alpha.o
>  common-obj-$(CONFIG_ARM_DIS) += arm.o
>  common-obj-$(CONFIG_CRIS_DIS) += cris.o
> diff --git a/disas/aarch64-cxx.cc b/disas/aarch64-cxx.cc
> new file mode 100644
> index 0000000..524f5ae
> --- /dev/null
> +++ b/disas/aarch64-cxx.cc
> @@ -0,0 +1,53 @@
> +/*
> + * Aarch64 disassembly output wrapper to libvixl - C++ part
> + * Copyright (c) 2013 Linaro Limited
> + * Written by Claudio Fontana
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "a64/simulator-a64.h"
> +#include "a64/macro-assembler-a64.h"
> +
> +extern "C" {
> +    int vixl_is_initialized(int);
> +    int vixl_init(FILE *f);
> +    int vixl_decode_insn(uint8_t *bytes);
> +}
> +
> +using namespace vixl;
> +
> +static Decoder *vixl_decoder = NULL;
> +static Disassembler *vixl_disasm = NULL;
> +
> +int vixl_is_initialized(int unused)
> +{
> +    return vixl_decoder != NULL;
> +}
> +
> +/* Disassemble Aarch64 bytecode - wrappers */
> +int vixl_init(FILE *f) {
> +    vixl_decoder = new Decoder();
> +    vixl_disasm = new PrintDisassembler(f);
> +    vixl_decoder->AppendVisitor(vixl_disasm);
> +    return 1;
> +}
> +
> +int vixl_decode_insn(uint8_t *bytes)
> +{
> +    Instr instr;
> +    instr = bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24;
> +    vixl_decoder->Decode(reinterpret_cast<Instruction*>(&instr));
> +    return 1;
> +}
> diff --git a/disas/aarch64.c b/disas/aarch64.c
> new file mode 100644
> index 0000000..7e44837
> --- /dev/null
> +++ b/disas/aarch64.c
> @@ -0,0 +1,45 @@
> +/*
> + * Aarch64 disassembly output wrapper to libvixl - C part
> + * Copyright (c) 2013 Linaro Limited
> + * Written by Claudio Fontana
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "disas/bfd.h"
> +#define INSN_SIZE 4
> +
> +extern int vixl_is_initialized(int);
> +extern int vixl_init(FILE *);
> +extern int vixl_decode_insn(uint8_t *);
> +
> +/* Disassemble Aarch64 bytecode. */
> +int print_insn_aarch64(uint64_t addr, disassemble_info *info)
> +{
> +    uint8_t bytes[INSN_SIZE];
> +    int status;
> +
> +    if (!vixl_is_initialized(0)) {
> +        vixl_init(info->stream);
> +    }
> +
> +    status = info->read_memory_func(addr, bytes, INSN_SIZE, info);
> +    if (status != 0) {
> +        info->memory_error_func(status, addr, info);
> +        return -1;
> +    }
> +
> +    vixl_decode_insn(bytes);
> +    return INSN_SIZE;
> +}

Why split this into two mini files? You're already using extern "C" {
... } in the C++ file for the prototypes anyway.

Apart from that the library integration looks surprisingly clean. :)

Cheers,
Andreas

> diff --git a/disas/libvixl/Makefile.objs b/disas/libvixl/Makefile.objs
> new file mode 100644
> index 0000000..43ba29c
> --- /dev/null
> +++ b/disas/libvixl/Makefile.objs
> @@ -0,0 +1,6 @@
> +libvixl_OBJS = src/utils.o \
> +               src/a64/instructions-a64.o \
> +               src/a64/decoder-a64.o \
> +               src/a64/disasm-a64.o
> +
> +common-obj-$(CONFIG_AARCH64_DIS) += $(libvixl_OBJS)
> diff --git a/include/disas/bfd.h b/include/disas/bfd.h
> index 803b6ef..73017da 100644
> --- a/include/disas/bfd.h
> +++ b/include/disas/bfd.h
> @@ -379,6 +379,7 @@ int print_insn_h8300            (bfd_vma, 
> disassemble_info*);
>  int print_insn_h8300h           (bfd_vma, disassemble_info*);
>  int print_insn_h8300s           (bfd_vma, disassemble_info*);
>  int print_insn_h8500            (bfd_vma, disassemble_info*);
> +int print_insn_aarch64          (bfd_vma, disassemble_info*);
>  int print_insn_alpha            (bfd_vma, disassemble_info*);
>  disassembler_ftype arc_get_disassembler (int, int);
>  int print_insn_arm              (bfd_vma, disassemble_info*);
> 


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