Re: [PATCH 2/7] Move some integer operations to common.

Antoine Tremblay
2015-09-11T17:16:12Z

On 09/11/2015 10:24 AM, Gary Benson wrote:
> Hi Antoine,
>
> Please don't introduce "#ifdef GDBSERVER" conditionals into common
> code, I spent some time removing them. I know I didn't get them
> all, but the remaining two are on my hit list.
>

Humm what is the issue that makes this a bad idea if I may ?

> To work around this... do you really need to deal with endianness in
> gdbserver? It's running on the target so if you're pulling numbers
> from target memory in target endianness then could you use or
> generalize target_read_uint32 for your needs?
>

Yes unfortunately I do need the endianness since the program can be in a
different endianness then GDBServer the code section can even be
different than the data section...

I could however :

- Remove int-utils.h from common-defs.h and move to defs.h for GDB
- Move the int-utils.h in server.h for GDBServer which is kinda the
GDBServer's equivalent of defs.h with the BFD defines before the include...

Does that sound ok ?

> Antoine Tremblay wrote:
>> This patch is in preparation for sharing code between GDB and GDBServer to
>> enable software single stepping on ARM aarch32-linux.
>>
>> It moves multiple functions related to extracting or storing a value based on
>> its endianness from findvar.c in gdb to a new file called int-utils.c in
>> common.
>>
>> Definitions of these functions are also moved to defs.h to common-defs.h.
>>
>> gdb/ChangeLog:
>> * Makefile.in: Add int-utils.o.
>> * common/common-defs.h: New functions defs from defs.h.
>> * common/int-utils.c: New file.
>> * common/int-utils.h: New file.
>> * defs.h: Move functions defs to common-defs.h.
>> * findvar.c (extract_signed_integer): Move to int-utils.c.
>> (extract_unsigned_integer): Likewise.
>> (extract_long_unsigned_integer): Likewise.
>> (store_signed_integer): Likewise.
>> (store_unsigned_integer): Likewise.
>> ---
>> gdb/Makefile.in | 9 ++-
>> gdb/common/common-defs.h | 1 +
>> gdb/common/int-utils.c | 199 +++++++++++++++++++++++++++++++++++++++++++++++
>> gdb/common/int-utils.h | 45 +++++++++++
>> gdb/defs.h | 16 ----
>> gdb/findvar.c | 176 -----------------------------------------
>> 6 files changed, 252 insertions(+), 194 deletions(-)
>> create mode 100644 gdb/common/int-utils.c
>> create mode 100644 gdb/common/int-utils.h
>>
>> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
>> index 0d7cf97..e20c5a6 100644
>> --- a/gdb/Makefile.in
>> +++ b/gdb/Makefile.in
>> @@ -854,6 +854,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
>> infcall.c \
>> infcmd.c inflow.c infrun.c \
>> inline-frame.c \
>> + common/int-utils.c \
>> interps.c \
>> jv-exp.y jv-lang.c jv-valprint.c jv-typeprint.c jv-varobj.c \
>> language.c linespec.c location.c minidebug.c \
>> @@ -985,7 +986,7 @@ i386-linux-nat.h common/common-defs.h common/errors.h common/common-types.h \
>> common/common-debug.h common/cleanups.h common/gdb_setjmp.h \
>> common/common-exceptions.h target/target.h common/symbol.h \
>> common/common-regcache.h fbsd-tdep.h nat/linux-personality.h \
>> -common/fileio.h nat/x86-linux.h nat/x86-linux-dregs.h \
>> +common/fileio.h nat/x86-linux.h nat/x86-linux-dregs.h common/int-utils.h \
>> nat/linux-namespaces.h arch/arm.h common/gdb_sys_time.h
>>
>> # Header files that already have srcdir in them, or which are in objdir.
>> @@ -1084,7 +1085,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
>> common-utils.o buffer.o ptid.o gdb-dlfcn.o common-agent.o \
>> format.o registry.o btrace.o record-btrace.o waitstatus.o \
>> print-utils.o rsp-low.o errors.o common-debug.o debug.o \
>> - common-exceptions.o btrace-common.o fileio.o \
>> + common-exceptions.o btrace-common.o fileio.o int-utils.o \
>> $(SUBDIR_GCC_COMPILE_OBS)
>>
>> TSOBS = inflow.o
>> @@ -2265,6 +2266,10 @@ btrace-common.o: ${srcdir}/common/btrace-common.c
>> fileio.o: ${srcdir}/common/fileio.c
>> $(COMPILE) $(srcdir)/common/fileio.c
>> $(POSTCOMPILE)
>> +int-utils.o: ${srcdir}/common/int-utils.c
>> + $(COMPILE) $(srcdir)/common/int-utils.c
>> + $(POSTCOMPILE)
>> +
>> #
>> # gdb/target/ dependencies
>> #
>> diff --git a/gdb/common/common-defs.h b/gdb/common/common-defs.h
>> index 2be0d7d..cb79234 100644
>> --- a/gdb/common/common-defs.h
>> +++ b/gdb/common/common-defs.h
>> @@ -49,6 +49,7 @@
>> #include "common-debug.h"
>> #include "cleanups.h"
>> #include "common-exceptions.h"
>> +#include "int-utils.h"
>>
>> #ifdef __cplusplus
>> # define EXTERN_C extern "C"
>> diff --git a/gdb/common/int-utils.c b/gdb/common/int-utils.c
>> new file mode 100644
>> index 0000000..57d0dba
>> --- /dev/null
>> +++ b/gdb/common/int-utils.c
>> @@ -0,0 +1,199 @@
>> +/* Shared utility routines for integer endianness manipulations.
>> + Copyright (C) 2015 Free Software Foundation, Inc.
>> +
>> + This file is part of GDB.
>> +
>> + 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 3 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 "common-defs.h"
>> +
>> +/* Basic byte-swapping routines. All 'extract' functions return a
>> + host-format integer from a target-format integer at ADDR which is
>> + LEN bytes long. */
>> +
>> +LONGEST
>> +extract_signed_integer (const gdb_byte *addr, int len,
>> + enum bfd_endian byte_order)
>> +{
>> + LONGEST retval;
>> + const unsigned char *p;
>> + const unsigned char *startaddr = addr;
>> + const unsigned char *endaddr = startaddr + len;
>> +
>> + if (len > (int) sizeof (LONGEST))
>> + error (_("\
>> +That operation is not available on integers of more than %d bytes."),
>> + (int) sizeof (LONGEST));
>> +
>> + /* Start at the most significant end of the integer, and work towards
>> + the least significant. */
>> + if (byte_order == BFD_ENDIAN_BIG)
>> + {
>> + p = startaddr;
>> + /* Do the sign extension once at the start. */
>> + retval = ((LONGEST) * p ^ 0x80) - 0x80;
>> + for (++p; p < endaddr; ++p)
>> + retval = (retval << 8) | *p;
>> + }
>> + else
>> + {
>> + p = endaddr - 1;
>> + /* Do the sign extension once at the start. */
>> + retval = ((LONGEST) * p ^ 0x80) - 0x80;
>> + for (--p; p >= startaddr; --p)
>> + retval = (retval << 8) | *p;
>> + }
>> + return retval;
>> +}
>> +
>> +ULONGEST
>> +extract_unsigned_integer (const gdb_byte *addr, int len,
>> + enum bfd_endian byte_order)
>> +{
>> + ULONGEST retval;
>> + const unsigned char *p;
>> + const unsigned char *startaddr = addr;
>> + const unsigned char *endaddr = startaddr + len;
>> +
>> + if (len > (int) sizeof (ULONGEST))
>> + error (_("\
>> +That operation is not available on integers of more than %d bytes."),
>> + (int) sizeof (ULONGEST));
>> +
>> + /* Start at the most significant end of the integer, and work towards
>> + the least significant. */
>> + retval = 0;
>> + if (byte_order == BFD_ENDIAN_BIG)
>> + {
>> + for (p = startaddr; p < endaddr; ++p)
>> + retval = (retval << 8) | *p;
>> + }
>> + else
>> + {
>> + for (p = endaddr - 1; p >= startaddr; --p)
>> + retval = (retval << 8) | *p;
>> + }
>> + return retval;
>> +}
>> +
>> +/* Sometimes a long long unsigned integer can be extracted as a
>> + LONGEST value. This is done so that we can print these values
>> + better. If this integer can be converted to a LONGEST, this
>> + function returns 1 and sets *PVAL. Otherwise it returns 0. */
>> +
>> +int
>> +extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
>> + enum bfd_endian byte_order, LONGEST *pval)
>> +{
>> + const gdb_byte *p;
>> + const gdb_byte *first_addr;
>> + int len;
>> +
>> + len = orig_len;
>> + if (byte_order == BFD_ENDIAN_BIG)
>> + {
>> + for (p = addr;
>> + len > (int) sizeof (LONGEST) && p < addr + orig_len;
>> + p++)
>> + {
>> + if (*p == 0)
>> + len--;
>> + else
>> + break;
>> + }
>> + first_addr = p;
>> + }
>> + else
>> + {
>> + first_addr = addr;
>> + for (p = addr + orig_len - 1;
>> + len > (int) sizeof (LONGEST) && p >= addr;
>> + p--)
>> + {
>> + if (*p == 0)
>> + len--;
>> + else
>> + break;
>> + }
>> + }
>> +
>> + if (len <= (int) sizeof (LONGEST))
>> + {
>> + *pval = (LONGEST) extract_unsigned_integer (first_addr,
>> + sizeof (LONGEST),
>> + byte_order);
>> + return 1;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/* All 'store' functions accept a host-format integer and store a
>> + target-format integer at ADDR which is LEN bytes long. */
>> +
>> +void
>> +store_signed_integer (gdb_byte *addr, int len,
>> + enum bfd_endian byte_order, LONGEST val)
>> +{
>> + gdb_byte *p;
>> + gdb_byte *startaddr = addr;
>> + gdb_byte *endaddr = startaddr + len;
>> +
>> + /* Start at the least significant end of the integer, and work towards
>> + the most significant. */
>> + if (byte_order == BFD_ENDIAN_BIG)
>> + {
>> + for (p = endaddr - 1; p >= startaddr; --p)
>> + {
>> + *p = val & 0xff;
>> + val >>= 8;
>> + }
>> + }
>> + else
>> + {
>> + for (p = startaddr; p < endaddr; ++p)
>> + {
>> + *p = val & 0xff;
>> + val >>= 8;
>> + }
>> + }
>> +}
>> +
>> +void
>> +store_unsigned_integer (gdb_byte *addr, int len,
>> + enum bfd_endian byte_order, ULONGEST val)
>> +{
>> + unsigned char *p;
>> + unsigned char *startaddr = (unsigned char *) addr;
>> + unsigned char *endaddr = startaddr + len;
>> +
>> + /* Start at the least significant end of the integer, and work towards
>> + the most significant. */
>> + if (byte_order == BFD_ENDIAN_BIG)
>> + {
>> + for (p = endaddr - 1; p >= startaddr; --p)
>> + {
>> + *p = val & 0xff;
>> + val >>= 8;
>> + }
>> + }
>> + else
>> + {
>> + for (p = startaddr; p < endaddr; ++p)
>> + {
>> + *p = val & 0xff;
>> + val >>= 8;
>> + }
>> + }
>> +}
>> diff --git a/gdb/common/int-utils.h b/gdb/common/int-utils.h
>> new file mode 100644
>> index 0000000..c170348
>> --- /dev/null
>> +++ b/gdb/common/int-utils.h
>> @@ -0,0 +1,45 @@
>> +/* Shared utility routines for integer endianness manipulations.
>> + Copyright (C) 2015 Free Software Foundation, Inc.
>> +
>> + This file is part of GDB.
>> +
>> + 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 3 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/>. */
>> +
>> +
>> +#ifndef INT_UTILS_H
>> +#define INT_UTILS_H 1
>> +
>> +#ifdef GDBSERVER
>> +/* Allow this enum without requiring bfd in gdbserver. */
>> +enum bfd_endian { BFD_ENDIAN_BIG, BFD_ENDIAN_LITTLE, BFD_ENDIAN_UNKNOWN };
>> +#else
>> +#include "bfd.h"
>> +#endif
>> +
>> +extern LONGEST extract_signed_integer (const gdb_byte *, int,
>> + enum bfd_endian);
>> +
>> +extern ULONGEST extract_unsigned_integer (const gdb_byte *, int,
>> + enum bfd_endian);
>> +
>> +extern int extract_long_unsigned_integer (const gdb_byte *, int,
>> + enum bfd_endian, LONGEST *);
>> +
>> +extern void store_signed_integer (gdb_byte *, int,
>> + enum bfd_endian, LONGEST);
>> +
>> +extern void store_unsigned_integer (gdb_byte *, int,
>> + enum bfd_endian, ULONGEST);
>> +
>> +#endif /* INT_UTILS_H */
>> diff --git a/gdb/defs.h b/gdb/defs.h
>> index 03f7e8a..e292977 100644
>> --- a/gdb/defs.h
>> +++ b/gdb/defs.h
>> @@ -596,28 +596,12 @@ enum { MAX_REGISTER_SIZE = 64 };
>>
>> /* In findvar.c. */
>>
>> -extern LONGEST extract_signed_integer (const gdb_byte *, int,
>> - enum bfd_endian);
>> -
>> -extern ULONGEST extract_unsigned_integer (const gdb_byte *, int,
>> - enum bfd_endian);
>> -
>> -extern int extract_long_unsigned_integer (const gdb_byte *, int,
>> - enum bfd_endian, LONGEST *);
>> -
>> extern CORE_ADDR extract_typed_address (const gdb_byte *buf,
>> struct type *type);
>>
>> -extern void store_signed_integer (gdb_byte *, int,
>> - enum bfd_endian, LONGEST);
>> -
>> -extern void store_unsigned_integer (gdb_byte *, int,
>> - enum bfd_endian, ULONGEST);
>> -
>> extern void store_typed_address (gdb_byte *buf, struct type *type,
>> CORE_ADDR addr);
>>
>> -\f
>> /* From valops.c */
>>
>> extern int watchdog;
>> diff --git a/gdb/findvar.c b/gdb/findvar.c
>> index 1c077f7..2299ca4 100644
>> --- a/gdb/findvar.c
>> +++ b/gdb/findvar.c
>> @@ -46,124 +46,6 @@
>> you lose
>> #endif
>>
>> -LONGEST
>> -extract_signed_integer (const gdb_byte *addr, int len,
>> - enum bfd_endian byte_order)
>> -{
>> - LONGEST retval;
>> - const unsigned char *p;
>> - const unsigned char *startaddr = addr;
>> - const unsigned char *endaddr = startaddr + len;
>> -
>> - if (len > (int) sizeof (LONGEST))
>> - error (_("\
>> -That operation is not available on integers of more than %d bytes."),
>> - (int) sizeof (LONGEST));
>> -
>> - /* Start at the most significant end of the integer, and work towards
>> - the least significant. */
>> - if (byte_order == BFD_ENDIAN_BIG)
>> - {
>> - p = startaddr;
>> - /* Do the sign extension once at the start. */
>> - retval = ((LONGEST) * p ^ 0x80) - 0x80;
>> - for (++p; p < endaddr; ++p)
>> - retval = (retval << 8) | *p;
>> - }
>> - else
>> - {
>> - p = endaddr - 1;
>> - /* Do the sign extension once at the start. */
>> - retval = ((LONGEST) * p ^ 0x80) - 0x80;
>> - for (--p; p >= startaddr; --p)
>> - retval = (retval << 8) | *p;
>> - }
>> - return retval;
>> -}
>> -
>> -ULONGEST
>> -extract_unsigned_integer (const gdb_byte *addr, int len,
>> - enum bfd_endian byte_order)
>> -{
>> - ULONGEST retval;
>> - const unsigned char *p;
>> - const unsigned char *startaddr = addr;
>> - const unsigned char *endaddr = startaddr + len;
>> -
>> - if (len > (int) sizeof (ULONGEST))
>> - error (_("\
>> -That operation is not available on integers of more than %d bytes."),
>> - (int) sizeof (ULONGEST));
>> -
>> - /* Start at the most significant end of the integer, and work towards
>> - the least significant. */
>> - retval = 0;
>> - if (byte_order == BFD_ENDIAN_BIG)
>> - {
>> - for (p = startaddr; p < endaddr; ++p)
>> - retval = (retval << 8) | *p;
>> - }
>> - else
>> - {
>> - for (p = endaddr - 1; p >= startaddr; --p)
>> - retval = (retval << 8) | *p;
>> - }
>> - return retval;
>> -}
>> -
>> -/* Sometimes a long long unsigned integer can be extracted as a
>> - LONGEST value. This is done so that we can print these values
>> - better. If this integer can be converted to a LONGEST, this
>> - function returns 1 and sets *PVAL. Otherwise it returns 0. */
>> -
>> -int
>> -extract_long_unsigned_integer (const gdb_byte *addr, int orig_len,
>> - enum bfd_endian byte_order, LONGEST *pval)
>> -{
>> - const gdb_byte *p;
>> - const gdb_byte *first_addr;
>> - int len;
>> -
>> - len = orig_len;
>> - if (byte_order == BFD_ENDIAN_BIG)
>> - {
>> - for (p = addr;
>> - len > (int) sizeof (LONGEST) && p < addr + orig_len;
>> - p++)
>> - {
>> - if (*p == 0)
>> - len--;
>> - else
>> - break;
>> - }
>> - first_addr = p;
>> - }
>> - else
>> - {
>> - first_addr = addr;
>> - for (p = addr + orig_len - 1;
>> - len > (int) sizeof (LONGEST) && p >= addr;
>> - p--)
>> - {
>> - if (*p == 0)
>> - len--;
>> - else
>> - break;
>> - }
>> - }
>> -
>> - if (len <= (int) sizeof (LONGEST))
>> - {
>> - *pval = (LONGEST) extract_unsigned_integer (first_addr,
>> - sizeof (LONGEST),
>> - byte_order);
>> - return 1;
>> - }
>> -
>> - return 0;
>> -}
>> -
>> -
>> /* Treat the bytes at BUF as a pointer of type TYPE, and return the
>> address it represents. */
>> CORE_ADDR
>> @@ -178,64 +60,6 @@ extract_typed_address (const gdb_byte *buf, struct type *type)
>> return gdbarch_pointer_to_address (get_type_arch (type), type, buf);
>> }
>>
>> -/* All 'store' functions accept a host-format integer and store a
>> - target-format integer at ADDR which is LEN bytes long. */
>> -
>> -void
>> -store_signed_integer (gdb_byte *addr, int len,
>> - enum bfd_endian byte_order, LONGEST val)
>> -{
>> - gdb_byte *p;
>> - gdb_byte *startaddr = addr;
>> - gdb_byte *endaddr = startaddr + len;
>> -
>> - /* Start at the least significant end of the integer, and work towards
>> - the most significant. */
>> - if (byte_order == BFD_ENDIAN_BIG)
>> - {
>> - for (p = endaddr - 1; p >= startaddr; --p)
>> - {
>> - *p = val & 0xff;
>> - val >>= 8;
>> - }
>> - }
>> - else
>> - {
>> - for (p = startaddr; p < endaddr; ++p)
>> - {
>> - *p = val & 0xff;
>> - val >>= 8;
>> - }
>> - }
>> -}
>> -
>> -void
>> -store_unsigned_integer (gdb_byte *addr, int len,
>> - enum bfd_endian byte_order, ULONGEST val)
>> -{
>> - unsigned char *p;
>> - unsigned char *startaddr = (unsigned char *) addr;
>> - unsigned char *endaddr = startaddr + len;
>> -
>> - /* Start at the least significant end of the integer, and work towards
>> - the most significant. */
>> - if (byte_order == BFD_ENDIAN_BIG)
>> - {
>> - for (p = endaddr - 1; p >= startaddr; --p)
>> - {
>> - *p = val & 0xff;
>> - val >>= 8;
>> - }
>> - }
>> - else
>> - {
>> - for (p = startaddr; p < endaddr; ++p)
>> - {
>> - *p = val & 0xff;
>> - val >>= 8;
>> - }
>> - }
>> -}
>>
>> /* Store the address ADDR as a pointer of type TYPE at BUF, in target
>> form. */
>> --
>> 1.9.1
>