binutils-gdb/gdb/arch/arm.c
Simon Marchi 5f661e0397 gnulib: import count-one-bits module and use it
For a fix I intend to submit, I would need a function that counts the
number of set bits in a word.  There is  __builtin_popcount that is
supported by gcc and clang, but there is also a gnulib module that wraps
that and provides a fallback for other compilers, so I think it would be
good to use it.

I also noticed that there is a bitcount function in arch/arm.c, so I
thought that as a first step I would replace that one with the gnulib
count-one-bits module.  This is what this patch does.

The gnulib module provides multiple functions, with various parameter
length (unsigned int, unsigned long int, unsigned long long int), I
chose the one that made sense for each call site based on the argument
type.

gnulib/ChangeLog:

	* update-gnulib.sh (IMPORTED_GNULIB_MODULES): Import
	count-one-bits module.
	* configure: Re-generate.
	* aclocal.m4: Re-generate.
	* Makefile.in: Re-generate.
	* import/count-one-bits.c: New file.
	* import/count-one-bits.h: New file.
	* import/Makefile.am: Re-generate.
	* import/Makefile.in: Re-generate.
	* import/m4/gnulib-cache.m4: Re-generate.
	* import/m4/gnulib-comp.m4: Re-generate.
	* import/m4/count-one-bits.m4: New file.

gdb/ChangeLog:

	* arm-tdep.c: Include count-one-bits.h.
	(cleanup_block_store_pc): Use count_one_bits.
	(cleanup_block_load_pc): Use count_one_bits.
	(arm_copy_block_xfer): Use count_one_bits.
	(thumb2_copy_block_xfer): Use count_one_bits.
	(thumb_copy_pop_pc_16bit): Use count_one_bits.
	* arch/arm-get-next-pcs.c: Include count-one-bits.h.
	(thumb_get_next_pcs_raw): Use count_one_bits.
	(arm_get_next_pcs_raw): Use count_one_bits_l.
	* arch/arm.c (bitcount): Remove.
	* arch/arm.h (bitcount): Remove.
2020-02-14 14:41:07 -05:00

448 lines
9.9 KiB
C

/* Common target dependent code for GDB on ARM systems.
Copyright (C) 1988-2020 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 "gdbsupport/common-defs.h"
#include "gdbsupport/common-regcache.h"
#include "arm.h"
#include "../features/arm/arm-core.c"
#include "../features/arm/arm-vfpv2.c"
#include "../features/arm/arm-vfpv3.c"
#include "../features/arm/xscale-iwmmxt.c"
#include "../features/arm/arm-m-profile.c"
#include "../features/arm/arm-m-profile-with-fpa.c"
/* See arm.h. */
int
thumb_insn_size (unsigned short inst1)
{
if ((inst1 & 0xe000) == 0xe000 && (inst1 & 0x1800) != 0)
return 4;
else
return 2;
}
/* See arm.h. */
int
condition_true (unsigned long cond, unsigned long status_reg)
{
if (cond == INST_AL || cond == INST_NV)
return 1;
switch (cond)
{
case INST_EQ:
return ((status_reg & FLAG_Z) != 0);
case INST_NE:
return ((status_reg & FLAG_Z) == 0);
case INST_CS:
return ((status_reg & FLAG_C) != 0);
case INST_CC:
return ((status_reg & FLAG_C) == 0);
case INST_MI:
return ((status_reg & FLAG_N) != 0);
case INST_PL:
return ((status_reg & FLAG_N) == 0);
case INST_VS:
return ((status_reg & FLAG_V) != 0);
case INST_VC:
return ((status_reg & FLAG_V) == 0);
case INST_HI:
return ((status_reg & (FLAG_C | FLAG_Z)) == FLAG_C);
case INST_LS:
return ((status_reg & (FLAG_C | FLAG_Z)) != FLAG_C);
case INST_GE:
return (((status_reg & FLAG_N) == 0) == ((status_reg & FLAG_V) == 0));
case INST_LT:
return (((status_reg & FLAG_N) == 0) != ((status_reg & FLAG_V) == 0));
case INST_GT:
return (((status_reg & FLAG_Z) == 0)
&& (((status_reg & FLAG_N) == 0)
== ((status_reg & FLAG_V) == 0)));
case INST_LE:
return (((status_reg & FLAG_Z) != 0)
|| (((status_reg & FLAG_N) == 0)
!= ((status_reg & FLAG_V) == 0)));
}
return 1;
}
/* See arm.h. */
int
thumb_advance_itstate (unsigned int itstate)
{
/* Preserve IT[7:5], the first three bits of the condition. Shift
the upcoming condition flags left by one bit. */
itstate = (itstate & 0xe0) | ((itstate << 1) & 0x1f);
/* If we have finished the IT block, clear the state. */
if ((itstate & 0x0f) == 0)
itstate = 0;
return itstate;
}
/* See arm.h. */
int
arm_instruction_changes_pc (uint32_t this_instr)
{
if (bits (this_instr, 28, 31) == INST_NV)
/* Unconditional instructions. */
switch (bits (this_instr, 24, 27))
{
case 0xa:
case 0xb:
/* Branch with Link and change to Thumb. */
return 1;
case 0xc:
case 0xd:
case 0xe:
/* Coprocessor register transfer. */
if (bits (this_instr, 12, 15) == 15)
error (_("Invalid update to pc in instruction"));
return 0;
default:
return 0;
}
else
switch (bits (this_instr, 25, 27))
{
case 0x0:
if (bits (this_instr, 23, 24) == 2 && bit (this_instr, 20) == 0)
{
/* Multiplies and extra load/stores. */
if (bit (this_instr, 4) == 1 && bit (this_instr, 7) == 1)
/* Neither multiplies nor extension load/stores are allowed
to modify PC. */
return 0;
/* Otherwise, miscellaneous instructions. */
/* BX <reg>, BXJ <reg>, BLX <reg> */
if (bits (this_instr, 4, 27) == 0x12fff1
|| bits (this_instr, 4, 27) == 0x12fff2
|| bits (this_instr, 4, 27) == 0x12fff3)
return 1;
/* Other miscellaneous instructions are unpredictable if they
modify PC. */
return 0;
}
/* Data processing instruction. */
/* Fall through. */
case 0x1:
if (bits (this_instr, 12, 15) == 15)
return 1;
else
return 0;
case 0x2:
case 0x3:
/* Media instructions and architecturally undefined instructions. */
if (bits (this_instr, 25, 27) == 3 && bit (this_instr, 4) == 1)
return 0;
/* Stores. */
if (bit (this_instr, 20) == 0)
return 0;
/* Loads. */
if (bits (this_instr, 12, 15) == ARM_PC_REGNUM)
return 1;
else
return 0;
case 0x4:
/* Load/store multiple. */
if (bit (this_instr, 20) == 1 && bit (this_instr, 15) == 1)
return 1;
else
return 0;
case 0x5:
/* Branch and branch with link. */
return 1;
case 0x6:
case 0x7:
/* Coprocessor transfers or SWIs can not affect PC. */
return 0;
default:
internal_error (__FILE__, __LINE__, _("bad value in switch"));
}
}
/* See arm.h. */
int
thumb_instruction_changes_pc (unsigned short inst)
{
if ((inst & 0xff00) == 0xbd00) /* pop {rlist, pc} */
return 1;
if ((inst & 0xf000) == 0xd000) /* conditional branch */
return 1;
if ((inst & 0xf800) == 0xe000) /* unconditional branch */
return 1;
if ((inst & 0xff00) == 0x4700) /* bx REG, blx REG */
return 1;
if ((inst & 0xff87) == 0x4687) /* mov pc, REG */
return 1;
if ((inst & 0xf500) == 0xb100) /* CBNZ or CBZ. */
return 1;
return 0;
}
/* See arm.h. */
int
thumb2_instruction_changes_pc (unsigned short inst1, unsigned short inst2)
{
if ((inst1 & 0xf800) == 0xf000 && (inst2 & 0x8000) == 0x8000)
{
/* Branches and miscellaneous control instructions. */
if ((inst2 & 0x1000) != 0 || (inst2 & 0xd001) == 0xc000)
{
/* B, BL, BLX. */
return 1;
}
else if (inst1 == 0xf3de && (inst2 & 0xff00) == 0x3f00)
{
/* SUBS PC, LR, #imm8. */
return 1;
}
else if ((inst2 & 0xd000) == 0x8000 && (inst1 & 0x0380) != 0x0380)
{
/* Conditional branch. */
return 1;
}
return 0;
}
if ((inst1 & 0xfe50) == 0xe810)
{
/* Load multiple or RFE. */
if (bit (inst1, 7) && !bit (inst1, 8))
{
/* LDMIA or POP */
if (bit (inst2, 15))
return 1;
}
else if (!bit (inst1, 7) && bit (inst1, 8))
{
/* LDMDB */
if (bit (inst2, 15))
return 1;
}
else if (bit (inst1, 7) && bit (inst1, 8))
{
/* RFEIA */
return 1;
}
else if (!bit (inst1, 7) && !bit (inst1, 8))
{
/* RFEDB */
return 1;
}
return 0;
}
if ((inst1 & 0xffef) == 0xea4f && (inst2 & 0xfff0) == 0x0f00)
{
/* MOV PC or MOVS PC. */
return 1;
}
if ((inst1 & 0xff70) == 0xf850 && (inst2 & 0xf000) == 0xf000)
{
/* LDR PC. */
if (bits (inst1, 0, 3) == 15)
return 1;
if (bit (inst1, 7))
return 1;
if (bit (inst2, 11))
return 1;
if ((inst2 & 0x0fc0) == 0x0000)
return 1;
return 0;
}
if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf000)
{
/* TBB. */
return 1;
}
if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf010)
{
/* TBH. */
return 1;
}
return 0;
}
/* See arm.h. */
unsigned long
shifted_reg_val (struct regcache *regcache, unsigned long inst,
int carry, unsigned long pc_val, unsigned long status_reg)
{
unsigned long res, shift;
int rm = bits (inst, 0, 3);
unsigned long shifttype = bits (inst, 5, 6);
if (bit (inst, 4))
{
int rs = bits (inst, 8, 11);
shift = (rs == 15
? pc_val + 8
: regcache_raw_get_unsigned (regcache, rs)) & 0xFF;
}
else
shift = bits (inst, 7, 11);
res = (rm == ARM_PC_REGNUM
? (pc_val + (bit (inst, 4) ? 12 : 8))
: regcache_raw_get_unsigned (regcache, rm));
switch (shifttype)
{
case 0: /* LSL */
res = shift >= 32 ? 0 : res << shift;
break;
case 1: /* LSR */
res = shift >= 32 ? 0 : res >> shift;
break;
case 2: /* ASR */
if (shift >= 32)
shift = 31;
res = ((res & 0x80000000L)
? ~((~res) >> shift) : res >> shift);
break;
case 3: /* ROR/RRX */
shift &= 31;
if (shift == 0)
res = (res >> 1) | (carry ? 0x80000000L : 0);
else
res = (res >> shift) | (res << (32 - shift));
break;
}
return res & 0xffffffff;
}
/* See arch/arm.h. */
target_desc *
arm_create_target_description (arm_fp_type fp_type)
{
target_desc *tdesc = allocate_target_description ();
#ifndef IN_PROCESS_AGENT
if (fp_type == ARM_FP_TYPE_IWMMXT)
set_tdesc_architecture (tdesc, "iwmmxt");
else
set_tdesc_architecture (tdesc, "arm");
#endif
long regnum = 0;
regnum = create_feature_arm_arm_core (tdesc, regnum);
switch (fp_type)
{
case ARM_FP_TYPE_NONE:
break;
case ARM_FP_TYPE_VFPV2:
regnum = create_feature_arm_arm_vfpv2 (tdesc, regnum);
break;
case ARM_FP_TYPE_VFPV3:
regnum = create_feature_arm_arm_vfpv3 (tdesc, regnum);
break;
case ARM_FP_TYPE_IWMMXT:
regnum = create_feature_arm_xscale_iwmmxt (tdesc, regnum);
break;
default:
error (_("Invalid Arm FP type: %d"), fp_type);
}
return tdesc;
}
/* See arch/arm.h. */
target_desc *
arm_create_mprofile_target_description (arm_m_profile_type m_type)
{
target_desc *tdesc = allocate_target_description ();
#ifndef IN_PROCESS_AGENT
set_tdesc_architecture (tdesc, "arm");
#endif
long regnum = 0;
switch (m_type)
{
case ARM_M_TYPE_M_PROFILE:
regnum = create_feature_arm_arm_m_profile (tdesc, regnum);
break;
case ARM_M_TYPE_VFP_D16:
regnum = create_feature_arm_arm_m_profile (tdesc, regnum);
regnum = create_feature_arm_arm_vfpv2 (tdesc, regnum);
break;
case ARM_M_TYPE_WITH_FPA:
regnum = create_feature_arm_arm_m_profile_with_fpa (tdesc, regnum);
break;
default:
error (_("Invalid Arm M type: %d"), m_type);
}
return tdesc;
}