/* Common target dependent code for GDB on ARM systems.
Copyright (C) 1988, 1989, 1991, 1992, 1993, 1995, 1996, 1998, 1999, 2000,
2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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 . */
#include /* XXX for isupper () */
#include "defs.h"
#include "frame.h"
#include "inferior.h"
#include "gdbcmd.h"
#include "gdbcore.h"
#include "gdb_string.h"
#include "dis-asm.h" /* For register styles. */
#include "regcache.h"
#include "doublest.h"
#include "value.h"
#include "arch-utils.h"
#include "osabi.h"
#include "frame-unwind.h"
#include "frame-base.h"
#include "trad-frame.h"
#include "objfiles.h"
#include "dwarf2-frame.h"
#include "gdbtypes.h"
#include "prologue-value.h"
#include "target-descriptions.h"
#include "user-regs.h"
#include "arm-tdep.h"
#include "gdb/sim-arm.h"
#include "elf-bfd.h"
#include "coff/internal.h"
#include "elf/arm.h"
#include "gdb_assert.h"
#include "vec.h"
static int arm_debug;
/* Macros for setting and testing a bit in a minimal symbol that marks
it as Thumb function. The MSB of the minimal symbol's "info" field
is used for this purpose.
MSYMBOL_SET_SPECIAL Actually sets the "special" bit.
MSYMBOL_IS_SPECIAL Tests the "special" bit in a minimal symbol. */
#define MSYMBOL_SET_SPECIAL(msym) \
MSYMBOL_TARGET_FLAG_1 (msym) = 1
#define MSYMBOL_IS_SPECIAL(msym) \
MSYMBOL_TARGET_FLAG_1 (msym)
/* Per-objfile data used for mapping symbols. */
static const struct objfile_data *arm_objfile_data_key;
struct arm_mapping_symbol
{
bfd_vma value;
char type;
};
typedef struct arm_mapping_symbol arm_mapping_symbol_s;
DEF_VEC_O(arm_mapping_symbol_s);
struct arm_per_objfile
{
VEC(arm_mapping_symbol_s) **section_maps;
};
/* The list of available "set arm ..." and "show arm ..." commands. */
static struct cmd_list_element *setarmcmdlist = NULL;
static struct cmd_list_element *showarmcmdlist = NULL;
/* The type of floating-point to use. Keep this in sync with enum
arm_float_model, and the help string in _initialize_arm_tdep. */
static const char *fp_model_strings[] =
{
"auto",
"softfpa",
"fpa",
"softvfp",
"vfp",
NULL
};
/* A variable that can be configured by the user. */
static enum arm_float_model arm_fp_model = ARM_FLOAT_AUTO;
static const char *current_fp_model = "auto";
/* The ABI to use. Keep this in sync with arm_abi_kind. */
static const char *arm_abi_strings[] =
{
"auto",
"APCS",
"AAPCS",
NULL
};
/* A variable that can be configured by the user. */
static enum arm_abi_kind arm_abi_global = ARM_ABI_AUTO;
static const char *arm_abi_string = "auto";
/* The execution mode to assume. */
static const char *arm_mode_strings[] =
{
"auto",
"arm",
"thumb"
};
static const char *arm_fallback_mode_string = "auto";
static const char *arm_force_mode_string = "auto";
/* Number of different reg name sets (options). */
static int num_disassembly_options;
/* The standard register names, and all the valid aliases for them. */
static const struct
{
const char *name;
int regnum;
} arm_register_aliases[] = {
/* Basic register numbers. */
{ "r0", 0 },
{ "r1", 1 },
{ "r2", 2 },
{ "r3", 3 },
{ "r4", 4 },
{ "r5", 5 },
{ "r6", 6 },
{ "r7", 7 },
{ "r8", 8 },
{ "r9", 9 },
{ "r10", 10 },
{ "r11", 11 },
{ "r12", 12 },
{ "r13", 13 },
{ "r14", 14 },
{ "r15", 15 },
/* Synonyms (argument and variable registers). */
{ "a1", 0 },
{ "a2", 1 },
{ "a3", 2 },
{ "a4", 3 },
{ "v1", 4 },
{ "v2", 5 },
{ "v3", 6 },
{ "v4", 7 },
{ "v5", 8 },
{ "v6", 9 },
{ "v7", 10 },
{ "v8", 11 },
/* Other platform-specific names for r9. */
{ "sb", 9 },
{ "tr", 9 },
/* Special names. */
{ "ip", 12 },
{ "sp", 13 },
{ "lr", 14 },
{ "pc", 15 },
/* Names used by GCC (not listed in the ARM EABI). */
{ "sl", 10 },
{ "fp", 11 },
/* A special name from the older ATPCS. */
{ "wr", 7 },
};
static const char *const arm_register_names[] =
{"r0", "r1", "r2", "r3", /* 0 1 2 3 */
"r4", "r5", "r6", "r7", /* 4 5 6 7 */
"r8", "r9", "r10", "r11", /* 8 9 10 11 */
"r12", "sp", "lr", "pc", /* 12 13 14 15 */
"f0", "f1", "f2", "f3", /* 16 17 18 19 */
"f4", "f5", "f6", "f7", /* 20 21 22 23 */
"fps", "cpsr" }; /* 24 25 */
/* Valid register name styles. */
static const char **valid_disassembly_styles;
/* Disassembly style to use. Default to "std" register names. */
static const char *disassembly_style;
/* This is used to keep the bfd arch_info in sync with the disassembly
style. */
static void set_disassembly_style_sfunc(char *, int,
struct cmd_list_element *);
static void set_disassembly_style (void);
static void convert_from_extended (const struct floatformat *, const void *,
void *, int);
static void convert_to_extended (const struct floatformat *, void *,
const void *, int);
static void arm_neon_quad_read (struct gdbarch *gdbarch,
struct regcache *regcache,
int regnum, gdb_byte *buf);
static void arm_neon_quad_write (struct gdbarch *gdbarch,
struct regcache *regcache,
int regnum, const gdb_byte *buf);
struct arm_prologue_cache
{
/* The stack pointer at the time this frame was created; i.e. the
caller's stack pointer when this function was called. It is used
to identify this frame. */
CORE_ADDR prev_sp;
/* The frame base for this frame is just prev_sp - frame size.
FRAMESIZE is the distance from the frame pointer to the
initial stack pointer. */
int framesize;
/* The register used to hold the frame pointer for this frame. */
int framereg;
/* Saved register offsets. */
struct trad_frame_saved_reg *saved_regs;
};
/* Architecture version for displaced stepping. This effects the behaviour of
certain instructions, and really should not be hard-wired. */
#define DISPLACED_STEPPING_ARCH_VERSION 5
/* Addresses for calling Thumb functions have the bit 0 set.
Here are some macros to test, set, or clear bit 0 of addresses. */
#define IS_THUMB_ADDR(addr) ((addr) & 1)
#define MAKE_THUMB_ADDR(addr) ((addr) | 1)
#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
/* Set to true if the 32-bit mode is in use. */
int arm_apcs_32 = 1;
/* Determine if FRAME is executing in Thumb mode. */
static int
arm_frame_is_thumb (struct frame_info *frame)
{
CORE_ADDR cpsr;
/* Every ARM frame unwinder can unwind the T bit of the CPSR, either
directly (from a signal frame or dummy frame) or by interpreting
the saved LR (from a prologue or DWARF frame). So consult it and
trust the unwinders. */
cpsr = get_frame_register_unsigned (frame, ARM_PS_REGNUM);
return (cpsr & CPSR_T) != 0;
}
/* Callback for VEC_lower_bound. */
static inline int
arm_compare_mapping_symbols (const struct arm_mapping_symbol *lhs,
const struct arm_mapping_symbol *rhs)
{
return lhs->value < rhs->value;
}
/* Determine if the program counter specified in MEMADDR is in a Thumb
function. This function should be called for addresses unrelated to
any executing frame; otherwise, prefer arm_frame_is_thumb. */
static int
arm_pc_is_thumb (CORE_ADDR memaddr)
{
struct obj_section *sec;
struct minimal_symbol *sym;
/* If bit 0 of the address is set, assume this is a Thumb address. */
if (IS_THUMB_ADDR (memaddr))
return 1;
/* If the user wants to override the symbol table, let him. */
if (strcmp (arm_force_mode_string, "arm") == 0)
return 0;
if (strcmp (arm_force_mode_string, "thumb") == 0)
return 1;
/* If there are mapping symbols, consult them. */
sec = find_pc_section (memaddr);
if (sec != NULL)
{
struct arm_per_objfile *data;
VEC(arm_mapping_symbol_s) *map;
struct arm_mapping_symbol map_key = { memaddr - obj_section_addr (sec),
0 };
unsigned int idx;
data = objfile_data (sec->objfile, arm_objfile_data_key);
if (data != NULL)
{
map = data->section_maps[sec->the_bfd_section->index];
if (!VEC_empty (arm_mapping_symbol_s, map))
{
struct arm_mapping_symbol *map_sym;
idx = VEC_lower_bound (arm_mapping_symbol_s, map, &map_key,
arm_compare_mapping_symbols);
/* VEC_lower_bound finds the earliest ordered insertion
point. If the following symbol starts at this exact
address, we use that; otherwise, the preceding
mapping symbol covers this address. */
if (idx < VEC_length (arm_mapping_symbol_s, map))
{
map_sym = VEC_index (arm_mapping_symbol_s, map, idx);
if (map_sym->value == map_key.value)
return map_sym->type == 't';
}
if (idx > 0)
{
map_sym = VEC_index (arm_mapping_symbol_s, map, idx - 1);
return map_sym->type == 't';
}
}
}
}
/* Thumb functions have a "special" bit set in minimal symbols. */
sym = lookup_minimal_symbol_by_pc (memaddr);
if (sym)
return (MSYMBOL_IS_SPECIAL (sym));
/* If the user wants to override the fallback mode, let them. */
if (strcmp (arm_fallback_mode_string, "arm") == 0)
return 0;
if (strcmp (arm_fallback_mode_string, "thumb") == 0)
return 1;
/* If we couldn't find any symbol, but we're talking to a running
target, then trust the current value of $cpsr. This lets
"display/i $pc" always show the correct mode (though if there is
a symbol table we will not reach here, so it still may not be
displayed in the mode it will be executed). */
if (target_has_registers)
return arm_frame_is_thumb (get_current_frame ());
/* Otherwise we're out of luck; we assume ARM. */
return 0;
}
/* Remove useless bits from addresses in a running program. */
static CORE_ADDR
arm_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val)
{
if (arm_apcs_32)
return UNMAKE_THUMB_ADDR (val);
else
return (val & 0x03fffffc);
}
/* When reading symbols, we need to zap the low bit of the address,
which may be set to 1 for Thumb functions. */
static CORE_ADDR
arm_smash_text_address (struct gdbarch *gdbarch, CORE_ADDR val)
{
return val & ~1;
}
/* Analyze a Thumb prologue, looking for a recognizable stack frame
and frame pointer. Scan until we encounter a store that could
clobber the stack frame unexpectedly, or an unknown instruction. */
static CORE_ADDR
thumb_analyze_prologue (struct gdbarch *gdbarch,
CORE_ADDR start, CORE_ADDR limit,
struct arm_prologue_cache *cache)
{
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
int i;
pv_t regs[16];
struct pv_area *stack;
struct cleanup *back_to;
CORE_ADDR offset;
for (i = 0; i < 16; i++)
regs[i] = pv_register (i, 0);
stack = make_pv_area (ARM_SP_REGNUM, gdbarch_addr_bit (gdbarch));
back_to = make_cleanup_free_pv_area (stack);
while (start < limit)
{
unsigned short insn;
insn = read_memory_unsigned_integer (start, 2, byte_order_for_code);
if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
{
int regno;
int mask;
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
/* Bits 0-7 contain a mask for registers R0-R7. Bit 8 says
whether to save LR (R14). */
mask = (insn & 0xff) | ((insn & 0x100) << 6);
/* Calculate offsets of saved R0-R7 and LR. */
for (regno = ARM_LR_REGNUM; regno >= 0; regno--)
if (mask & (1 << regno))
{
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM],
-4);
pv_area_store (stack, regs[ARM_SP_REGNUM], 4, regs[regno]);
}
}
else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR
sub sp, #simm */
{
offset = (insn & 0x7f) << 2; /* get scaled offset */
if (insn & 0x80) /* Check for SUB. */
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM],
-offset);
else
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM],
offset);
}
else if ((insn & 0xff00) == 0xaf00) /* add r7, sp, #imm */
regs[THUMB_FP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM],
(insn & 0xff) << 2);
else if ((insn & 0xff00) == 0x4600) /* mov hi, lo or mov lo, hi */
{
int dst_reg = (insn & 0x7) + ((insn & 0x80) >> 4);
int src_reg = (insn & 0x78) >> 3;
regs[dst_reg] = regs[src_reg];
}
else if ((insn & 0xf800) == 0x9000) /* str rd, [sp, #off] */
{
/* Handle stores to the stack. Normally pushes are used,
but with GCC -mtpcs-frame, there may be other stores
in the prologue to create the frame. */
int regno = (insn >> 8) & 0x7;
pv_t addr;
offset = (insn & 0xff) << 2;
addr = pv_add_constant (regs[ARM_SP_REGNUM], offset);
if (pv_area_store_would_trash (stack, addr))
break;
pv_area_store (stack, addr, 4, regs[regno]);
}
else
{
/* We don't know what this instruction is. We're finished
scanning. NOTE: Recognizing more safe-to-ignore
instructions here will improve support for optimized
code. */
break;
}
start += 2;
}
if (cache == NULL)
{
do_cleanups (back_to);
return start;
}
if (pv_is_register (regs[ARM_FP_REGNUM], ARM_SP_REGNUM))
{
/* Frame pointer is fp. Frame size is constant. */
cache->framereg = ARM_FP_REGNUM;
cache->framesize = -regs[ARM_FP_REGNUM].k;
}
else if (pv_is_register (regs[THUMB_FP_REGNUM], ARM_SP_REGNUM))
{
/* Frame pointer is r7. Frame size is constant. */
cache->framereg = THUMB_FP_REGNUM;
cache->framesize = -regs[THUMB_FP_REGNUM].k;
}
else if (pv_is_register (regs[ARM_SP_REGNUM], ARM_SP_REGNUM))
{
/* Try the stack pointer... this is a bit desperate. */
cache->framereg = ARM_SP_REGNUM;
cache->framesize = -regs[ARM_SP_REGNUM].k;
}
else
{
/* We're just out of luck. We don't know where the frame is. */
cache->framereg = -1;
cache->framesize = 0;
}
for (i = 0; i < 16; i++)
if (pv_area_find_reg (stack, gdbarch, i, &offset))
cache->saved_regs[i].addr = offset;
do_cleanups (back_to);
return start;
}
/* Advance the PC across any function entry prologue instructions to
reach some "real" code.
The APCS (ARM Procedure Call Standard) defines the following
prologue:
mov ip, sp
[stmfd sp!, {a1,a2,a3,a4}]
stmfd sp!, {...,fp,ip,lr,pc}
[stfe f7, [sp, #-12]!]
[stfe f6, [sp, #-12]!]
[stfe f5, [sp, #-12]!]
[stfe f4, [sp, #-12]!]
sub fp, ip, #nn @@ nn == 20 or 4 depending on second insn */
static CORE_ADDR
arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
{
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
unsigned long inst;
CORE_ADDR skip_pc;
CORE_ADDR func_addr, limit_pc;
struct symtab_and_line sal;
/* If we're in a dummy frame, don't even try to skip the prologue. */
if (deprecated_pc_in_call_dummy (gdbarch, pc))
return pc;
/* See if we can determine the end of the prologue via the symbol table.
If so, then return either PC, or the PC after the prologue, whichever
is greater. */
if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
{
CORE_ADDR post_prologue_pc
= skip_prologue_using_sal (gdbarch, func_addr);
if (post_prologue_pc != 0)
return max (pc, post_prologue_pc);
}
/* Can't determine prologue from the symbol table, need to examine
instructions. */
/* Find an upper limit on the function prologue using the debug
information. If the debug information could not be used to provide
that bound, then use an arbitrary large number as the upper bound. */
/* Like arm_scan_prologue, stop no later than pc + 64. */
limit_pc = skip_prologue_using_sal (gdbarch, pc);
if (limit_pc == 0)
limit_pc = pc + 64; /* Magic. */
/* Check if this is Thumb code. */
if (arm_pc_is_thumb (pc))
return thumb_analyze_prologue (gdbarch, pc, limit_pc, NULL);
for (skip_pc = pc; skip_pc < limit_pc; skip_pc += 4)
{
inst = read_memory_unsigned_integer (skip_pc, 4, byte_order_for_code);
/* "mov ip, sp" is no longer a required part of the prologue. */
if (inst == 0xe1a0c00d) /* mov ip, sp */
continue;
if ((inst & 0xfffff000) == 0xe28dc000) /* add ip, sp #n */
continue;
if ((inst & 0xfffff000) == 0xe24dc000) /* sub ip, sp #n */
continue;
/* Some prologues begin with "str lr, [sp, #-4]!". */
if (inst == 0xe52de004) /* str lr, [sp, #-4]! */
continue;
if ((inst & 0xfffffff0) == 0xe92d0000) /* stmfd sp!,{a1,a2,a3,a4} */
continue;
if ((inst & 0xfffff800) == 0xe92dd800) /* stmfd sp!,{fp,ip,lr,pc} */
continue;
/* Any insns after this point may float into the code, if it makes
for better instruction scheduling, so we skip them only if we
find them, but still consider the function to be frame-ful. */
/* We may have either one sfmfd instruction here, or several stfe
insns, depending on the version of floating point code we
support. */
if ((inst & 0xffbf0fff) == 0xec2d0200) /* sfmfd fn, , [sp]! */
continue;
if ((inst & 0xffff8fff) == 0xed6d0103) /* stfe fn, [sp, #-12]! */
continue;
if ((inst & 0xfffff000) == 0xe24cb000) /* sub fp, ip, #nn */
continue;
if ((inst & 0xfffff000) == 0xe24dd000) /* sub sp, sp, #nn */
continue;
if ((inst & 0xffffc000) == 0xe54b0000 /* strb r(0123),[r11,#-nn] */
|| (inst & 0xffffc0f0) == 0xe14b00b0 /* strh r(0123),[r11,#-nn] */
|| (inst & 0xffffc000) == 0xe50b0000) /* str r(0123),[r11,#-nn] */
continue;
if ((inst & 0xffffc000) == 0xe5cd0000 /* strb r(0123),[sp,#nn] */
|| (inst & 0xffffc0f0) == 0xe1cd00b0 /* strh r(0123),[sp,#nn] */
|| (inst & 0xffffc000) == 0xe58d0000) /* str r(0123),[sp,#nn] */
continue;
/* Un-recognized instruction; stop scanning. */
break;
}
return skip_pc; /* End of prologue */
}
/* *INDENT-OFF* */
/* Function: thumb_scan_prologue (helper function for arm_scan_prologue)
This function decodes a Thumb function prologue to determine:
1) the size of the stack frame
2) which registers are saved on it
3) the offsets of saved regs
4) the offset from the stack pointer to the frame pointer
A typical Thumb function prologue would create this stack frame
(offsets relative to FP)
old SP -> 24 stack parameters
20 LR
16 R7
R7 -> 0 local variables (16 bytes)
SP -> -12 additional stack space (12 bytes)
The frame size would thus be 36 bytes, and the frame offset would be
12 bytes. The frame register is R7.
The comments for thumb_skip_prolog() describe the algorithm we use
to detect the end of the prolog. */
/* *INDENT-ON* */
static void
thumb_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR prev_pc,
CORE_ADDR block_addr, struct arm_prologue_cache *cache)
{
CORE_ADDR prologue_start;
CORE_ADDR prologue_end;
CORE_ADDR current_pc;
if (find_pc_partial_function (block_addr, NULL, &prologue_start,
&prologue_end))
{
struct symtab_and_line sal = find_pc_line (prologue_start, 0);
if (sal.line == 0) /* no line info, use current PC */
prologue_end = prev_pc;
else if (sal.end < prologue_end) /* next line begins after fn end */
prologue_end = sal.end; /* (probably means no prologue) */
}
else
/* We're in the boondocks: we have no idea where the start of the
function is. */
return;
prologue_end = min (prologue_end, prev_pc);
thumb_analyze_prologue (gdbarch, prologue_start, prologue_end, cache);
}
/* This function decodes an ARM function prologue to determine:
1) the size of the stack frame
2) which registers are saved on it
3) the offsets of saved regs
4) the offset from the stack pointer to the frame pointer
This information is stored in the "extra" fields of the frame_info.
There are two basic forms for the ARM prologue. The fixed argument
function call will look like:
mov ip, sp
stmfd sp!, {fp, ip, lr, pc}
sub fp, ip, #4
[sub sp, sp, #4]
Which would create this stack frame (offsets relative to FP):
IP -> 4 (caller's stack)
FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
-4 LR (return address in caller)
-8 IP (copy of caller's SP)
-12 FP (caller's FP)
SP -> -28 Local variables
The frame size would thus be 32 bytes, and the frame offset would be
28 bytes. The stmfd call can also save any of the vN registers it
plans to use, which increases the frame size accordingly.
Note: The stored PC is 8 off of the STMFD instruction that stored it
because the ARM Store instructions always store PC + 8 when you read
the PC register.
A variable argument function call will look like:
mov ip, sp
stmfd sp!, {a1, a2, a3, a4}
stmfd sp!, {fp, ip, lr, pc}
sub fp, ip, #20
Which would create this stack frame (offsets relative to FP):
IP -> 20 (caller's stack)
16 A4
12 A3
8 A2
4 A1
FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
-4 LR (return address in caller)
-8 IP (copy of caller's SP)
-12 FP (caller's FP)
SP -> -28 Local variables
The frame size would thus be 48 bytes, and the frame offset would be
28 bytes.
There is another potential complication, which is that the optimizer
will try to separate the store of fp in the "stmfd" instruction from
the "sub fp, ip, #NN" instruction. Almost anything can be there, so
we just key on the stmfd, and then scan for the "sub fp, ip, #NN"...
Also, note, the original version of the ARM toolchain claimed that there
should be an
instruction at the end of the prologue. I have never seen GCC produce
this, and the ARM docs don't mention it. We still test for it below in
case it happens...
*/
static void
arm_scan_prologue (struct frame_info *this_frame,
struct arm_prologue_cache *cache)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
int regno;
CORE_ADDR prologue_start, prologue_end, current_pc;
CORE_ADDR prev_pc = get_frame_pc (this_frame);
CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
pv_t regs[ARM_FPS_REGNUM];
struct pv_area *stack;
struct cleanup *back_to;
CORE_ADDR offset;
/* Assume there is no frame until proven otherwise. */
cache->framereg = ARM_SP_REGNUM;
cache->framesize = 0;
/* Check for Thumb prologue. */
if (arm_frame_is_thumb (this_frame))
{
thumb_scan_prologue (gdbarch, prev_pc, block_addr, cache);
return;
}
/* Find the function prologue. If we can't find the function in
the symbol table, peek in the stack frame to find the PC. */
if (find_pc_partial_function (block_addr, NULL, &prologue_start,
&prologue_end))
{
/* One way to find the end of the prologue (which works well
for unoptimized code) is to do the following:
struct symtab_and_line sal = find_pc_line (prologue_start, 0);
if (sal.line == 0)
prologue_end = prev_pc;
else if (sal.end < prologue_end)
prologue_end = sal.end;
This mechanism is very accurate so long as the optimizer
doesn't move any instructions from the function body into the
prologue. If this happens, sal.end will be the last
instruction in the first hunk of prologue code just before
the first instruction that the scheduler has moved from
the body to the prologue.
In order to make sure that we scan all of the prologue
instructions, we use a slightly less accurate mechanism which
may scan more than necessary. To help compensate for this
lack of accuracy, the prologue scanning loop below contains
several clauses which'll cause the loop to terminate early if
an implausible prologue instruction is encountered.
The expression
prologue_start + 64
is a suitable endpoint since it accounts for the largest
possible prologue plus up to five instructions inserted by
the scheduler. */
if (prologue_end > prologue_start + 64)
{
prologue_end = prologue_start + 64; /* See above. */
}
}
else
{
/* We have no symbol information. Our only option is to assume this
function has a standard stack frame and the normal frame register.
Then, we can find the value of our frame pointer on entrance to
the callee (or at the present moment if this is the innermost frame).
The value stored there should be the address of the stmfd + 8. */
CORE_ADDR frame_loc;
LONGEST return_value;
frame_loc = get_frame_register_unsigned (this_frame, ARM_FP_REGNUM);
if (!safe_read_memory_integer (frame_loc, 4, byte_order, &return_value))
return;
else
{
prologue_start = gdbarch_addr_bits_remove
(gdbarch, return_value) - 8;
prologue_end = prologue_start + 64; /* See above. */
}
}
if (prev_pc < prologue_end)
prologue_end = prev_pc;
/* Now search the prologue looking for instructions that set up the
frame pointer, adjust the stack pointer, and save registers.
Be careful, however, and if it doesn't look like a prologue,
don't try to scan it. If, for instance, a frameless function
begins with stmfd sp!, then we will tell ourselves there is
a frame, which will confuse stack traceback, as well as "finish"
and other operations that rely on a knowledge of the stack
traceback.
In the APCS, the prologue should start with "mov ip, sp" so
if we don't see this as the first insn, we will stop.
[Note: This doesn't seem to be true any longer, so it's now an
optional part of the prologue. - Kevin Buettner, 2001-11-20]
[Note further: The "mov ip,sp" only seems to be missing in
frameless functions at optimization level "-O2" or above,
in which case it is often (but not always) replaced by
"str lr, [sp, #-4]!". - Michael Snyder, 2002-04-23] */
for (regno = 0; regno < ARM_FPS_REGNUM; regno++)
regs[regno] = pv_register (regno, 0);
stack = make_pv_area (ARM_SP_REGNUM, gdbarch_addr_bit (gdbarch));
back_to = make_cleanup_free_pv_area (stack);
for (current_pc = prologue_start;
current_pc < prologue_end;
current_pc += 4)
{
unsigned int insn
= read_memory_unsigned_integer (current_pc, 4, byte_order_for_code);
if (insn == 0xe1a0c00d) /* mov ip, sp */
{
regs[ARM_IP_REGNUM] = regs[ARM_SP_REGNUM];
continue;
}
else if ((insn & 0xfffff000) == 0xe28dc000) /* add ip, sp #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32 - rot));
regs[ARM_IP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], imm);
continue;
}
else if ((insn & 0xfffff000) == 0xe24dc000) /* sub ip, sp #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32 - rot));
regs[ARM_IP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -imm);
continue;
}
else if (insn == 0xe52de004) /* str lr, [sp, #-4]! */
{
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -4);
pv_area_store (stack, regs[ARM_SP_REGNUM], 4, regs[ARM_LR_REGNUM]);
continue;
}
else if ((insn & 0xffff0000) == 0xe92d0000)
/* stmfd sp!, {..., fp, ip, lr, pc}
or
stmfd sp!, {a1, a2, a3, a4} */
{
int mask = insn & 0xffff;
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
/* Calculate offsets of saved registers. */
for (regno = ARM_PC_REGNUM; regno >= 0; regno--)
if (mask & (1 << regno))
{
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -4);
pv_area_store (stack, regs[ARM_SP_REGNUM], 4, regs[regno]);
}
}
else if ((insn & 0xffffc000) == 0xe54b0000 /* strb rx,[r11,#-n] */
|| (insn & 0xffffc0f0) == 0xe14b00b0 /* strh rx,[r11,#-n] */
|| (insn & 0xffffc000) == 0xe50b0000) /* str rx,[r11,#-n] */
{
/* No need to add this to saved_regs -- it's just an arg reg. */
continue;
}
else if ((insn & 0xffffc000) == 0xe5cd0000 /* strb rx,[sp,#n] */
|| (insn & 0xffffc0f0) == 0xe1cd00b0 /* strh rx,[sp,#n] */
|| (insn & 0xffffc000) == 0xe58d0000) /* str rx,[sp,#n] */
{
/* No need to add this to saved_regs -- it's just an arg reg. */
continue;
}
else if ((insn & 0xfffff000) == 0xe24cb000) /* sub fp, ip #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32 - rot));
regs[ARM_FP_REGNUM] = pv_add_constant (regs[ARM_IP_REGNUM], -imm);
}
else if ((insn & 0xfffff000) == 0xe24dd000) /* sub sp, sp #n */
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
imm = (imm >> rot) | (imm << (32 - rot));
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -imm);
}
else if ((insn & 0xffff7fff) == 0xed6d0103 /* stfe f?, [sp, -#c]! */
&& gdbarch_tdep (gdbarch)->have_fpa_registers)
{
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -12);
regno = ARM_F0_REGNUM + ((insn >> 12) & 0x07);
pv_area_store (stack, regs[ARM_SP_REGNUM], 12, regs[regno]);
}
else if ((insn & 0xffbf0fff) == 0xec2d0200 /* sfmfd f0, 4, [sp!] */
&& gdbarch_tdep (gdbarch)->have_fpa_registers)
{
int n_saved_fp_regs;
unsigned int fp_start_reg, fp_bound_reg;
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
if ((insn & 0x800) == 0x800) /* N0 is set */
{
if ((insn & 0x40000) == 0x40000) /* N1 is set */
n_saved_fp_regs = 3;
else
n_saved_fp_regs = 1;
}
else
{
if ((insn & 0x40000) == 0x40000) /* N1 is set */
n_saved_fp_regs = 2;
else
n_saved_fp_regs = 4;
}
fp_start_reg = ARM_F0_REGNUM + ((insn >> 12) & 0x7);
fp_bound_reg = fp_start_reg + n_saved_fp_regs;
for (; fp_start_reg < fp_bound_reg; fp_start_reg++)
{
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -12);
pv_area_store (stack, regs[ARM_SP_REGNUM], 12,
regs[fp_start_reg++]);
}
}
else if ((insn & 0xf0000000) != 0xe0000000)
break; /* Condition not true, exit early */
else if ((insn & 0xfe200000) == 0xe8200000) /* ldm? */
break; /* Don't scan past a block load */
else
/* The optimizer might shove anything into the prologue,
so we just skip what we don't recognize. */
continue;
}
/* The frame size is just the distance from the frame register
to the original stack pointer. */
if (pv_is_register (regs[ARM_FP_REGNUM], ARM_SP_REGNUM))
{
/* Frame pointer is fp. */
cache->framereg = ARM_FP_REGNUM;
cache->framesize = -regs[ARM_FP_REGNUM].k;
}
else if (pv_is_register (regs[ARM_SP_REGNUM], ARM_SP_REGNUM))
{
/* Try the stack pointer... this is a bit desperate. */
cache->framereg = ARM_SP_REGNUM;
cache->framesize = -regs[ARM_SP_REGNUM].k;
}
else
{
/* We're just out of luck. We don't know where the frame is. */
cache->framereg = -1;
cache->framesize = 0;
}
for (regno = 0; regno < ARM_FPS_REGNUM; regno++)
if (pv_area_find_reg (stack, gdbarch, regno, &offset))
cache->saved_regs[regno].addr = offset;
do_cleanups (back_to);
}
static struct arm_prologue_cache *
arm_make_prologue_cache (struct frame_info *this_frame)
{
int reg;
struct arm_prologue_cache *cache;
CORE_ADDR unwound_fp;
cache = FRAME_OBSTACK_ZALLOC (struct arm_prologue_cache);
cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
arm_scan_prologue (this_frame, cache);
unwound_fp = get_frame_register_unsigned (this_frame, cache->framereg);
if (unwound_fp == 0)
return cache;
cache->prev_sp = unwound_fp + cache->framesize;
/* Calculate actual addresses of saved registers using offsets
determined by arm_scan_prologue. */
for (reg = 0; reg < gdbarch_num_regs (get_frame_arch (this_frame)); reg++)
if (trad_frame_addr_p (cache->saved_regs, reg))
cache->saved_regs[reg].addr += cache->prev_sp;
return cache;
}
/* Our frame ID for a normal frame is the current function's starting PC
and the caller's SP when we were called. */
static void
arm_prologue_this_id (struct frame_info *this_frame,
void **this_cache,
struct frame_id *this_id)
{
struct arm_prologue_cache *cache;
struct frame_id id;
CORE_ADDR pc, func;
if (*this_cache == NULL)
*this_cache = arm_make_prologue_cache (this_frame);
cache = *this_cache;
/* This is meant to halt the backtrace at "_start". */
pc = get_frame_pc (this_frame);
if (pc <= gdbarch_tdep (get_frame_arch (this_frame))->lowest_pc)
return;
/* If we've hit a wall, stop. */
if (cache->prev_sp == 0)
return;
func = get_frame_func (this_frame);
id = frame_id_build (cache->prev_sp, func);
*this_id = id;
}
static struct value *
arm_prologue_prev_register (struct frame_info *this_frame,
void **this_cache,
int prev_regnum)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
struct arm_prologue_cache *cache;
if (*this_cache == NULL)
*this_cache = arm_make_prologue_cache (this_frame);
cache = *this_cache;
/* If we are asked to unwind the PC, then we need to return the LR
instead. The prologue may save PC, but it will point into this
frame's prologue, not the next frame's resume location. Also
strip the saved T bit. A valid LR may have the low bit set, but
a valid PC never does. */
if (prev_regnum == ARM_PC_REGNUM)
{
CORE_ADDR lr;
lr = frame_unwind_register_unsigned (this_frame, ARM_LR_REGNUM);
return frame_unwind_got_constant (this_frame, prev_regnum,
arm_addr_bits_remove (gdbarch, lr));
}
/* SP is generally not saved to the stack, but this frame is
identified by the next frame's stack pointer at the time of the call.
The value was already reconstructed into PREV_SP. */
if (prev_regnum == ARM_SP_REGNUM)
return frame_unwind_got_constant (this_frame, prev_regnum, cache->prev_sp);
/* The CPSR may have been changed by the call instruction and by the
called function. The only bit we can reconstruct is the T bit,
by checking the low bit of LR as of the call. This is a reliable
indicator of Thumb-ness except for some ARM v4T pre-interworking
Thumb code, which could get away with a clear low bit as long as
the called function did not use bx. Guess that all other
bits are unchanged; the condition flags are presumably lost,
but the processor status is likely valid. */
if (prev_regnum == ARM_PS_REGNUM)
{
CORE_ADDR lr, cpsr;
cpsr = get_frame_register_unsigned (this_frame, prev_regnum);
lr = frame_unwind_register_unsigned (this_frame, ARM_LR_REGNUM);
if (IS_THUMB_ADDR (lr))
cpsr |= CPSR_T;
else
cpsr &= ~CPSR_T;
return frame_unwind_got_constant (this_frame, prev_regnum, cpsr);
}
return trad_frame_get_prev_register (this_frame, cache->saved_regs,
prev_regnum);
}
struct frame_unwind arm_prologue_unwind = {
NORMAL_FRAME,
arm_prologue_this_id,
arm_prologue_prev_register,
NULL,
default_frame_sniffer
};
static struct arm_prologue_cache *
arm_make_stub_cache (struct frame_info *this_frame)
{
int reg;
struct arm_prologue_cache *cache;
CORE_ADDR unwound_fp;
cache = FRAME_OBSTACK_ZALLOC (struct arm_prologue_cache);
cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
cache->prev_sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
return cache;
}
/* Our frame ID for a stub frame is the current SP and LR. */
static void
arm_stub_this_id (struct frame_info *this_frame,
void **this_cache,
struct frame_id *this_id)
{
struct arm_prologue_cache *cache;
if (*this_cache == NULL)
*this_cache = arm_make_stub_cache (this_frame);
cache = *this_cache;
*this_id = frame_id_build (cache->prev_sp, get_frame_pc (this_frame));
}
static int
arm_stub_unwind_sniffer (const struct frame_unwind *self,
struct frame_info *this_frame,
void **this_prologue_cache)
{
CORE_ADDR addr_in_block;
char dummy[4];
addr_in_block = get_frame_address_in_block (this_frame);
if (in_plt_section (addr_in_block, NULL)
|| target_read_memory (get_frame_pc (this_frame), dummy, 4) != 0)
return 1;
return 0;
}
struct frame_unwind arm_stub_unwind = {
NORMAL_FRAME,
arm_stub_this_id,
arm_prologue_prev_register,
NULL,
arm_stub_unwind_sniffer
};
static CORE_ADDR
arm_normal_frame_base (struct frame_info *this_frame, void **this_cache)
{
struct arm_prologue_cache *cache;
if (*this_cache == NULL)
*this_cache = arm_make_prologue_cache (this_frame);
cache = *this_cache;
return cache->prev_sp - cache->framesize;
}
struct frame_base arm_normal_base = {
&arm_prologue_unwind,
arm_normal_frame_base,
arm_normal_frame_base,
arm_normal_frame_base
};
/* Assuming THIS_FRAME is a dummy, return the frame ID of that
dummy frame. The frame ID's base needs to match the TOS value
saved by save_dummy_frame_tos() and returned from
arm_push_dummy_call, and the PC needs to match the dummy frame's
breakpoint. */
static struct frame_id
arm_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
{
return frame_id_build (get_frame_register_unsigned (this_frame, ARM_SP_REGNUM),
get_frame_pc (this_frame));
}
/* Given THIS_FRAME, find the previous frame's resume PC (which will
be used to construct the previous frame's ID, after looking up the
containing function). */
static CORE_ADDR
arm_unwind_pc (struct gdbarch *gdbarch, struct frame_info *this_frame)
{
CORE_ADDR pc;
pc = frame_unwind_register_unsigned (this_frame, ARM_PC_REGNUM);
return arm_addr_bits_remove (gdbarch, pc);
}
static CORE_ADDR
arm_unwind_sp (struct gdbarch *gdbarch, struct frame_info *this_frame)
{
return frame_unwind_register_unsigned (this_frame, ARM_SP_REGNUM);
}
static struct value *
arm_dwarf2_prev_register (struct frame_info *this_frame, void **this_cache,
int regnum)
{
struct gdbarch * gdbarch = get_frame_arch (this_frame);
CORE_ADDR lr, cpsr;
switch (regnum)
{
case ARM_PC_REGNUM:
/* The PC is normally copied from the return column, which
describes saves of LR. However, that version may have an
extra bit set to indicate Thumb state. The bit is not
part of the PC. */
lr = frame_unwind_register_unsigned (this_frame, ARM_LR_REGNUM);
return frame_unwind_got_constant (this_frame, regnum,
arm_addr_bits_remove (gdbarch, lr));
case ARM_PS_REGNUM:
/* Reconstruct the T bit; see arm_prologue_prev_register for details. */
cpsr = get_frame_register_unsigned (this_frame, regnum);
lr = frame_unwind_register_unsigned (this_frame, ARM_LR_REGNUM);
if (IS_THUMB_ADDR (lr))
cpsr |= CPSR_T;
else
cpsr &= ~CPSR_T;
return frame_unwind_got_constant (this_frame, regnum, cpsr);
default:
internal_error (__FILE__, __LINE__,
_("Unexpected register %d"), regnum);
}
}
static void
arm_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
struct dwarf2_frame_state_reg *reg,
struct frame_info *this_frame)
{
switch (regnum)
{
case ARM_PC_REGNUM:
case ARM_PS_REGNUM:
reg->how = DWARF2_FRAME_REG_FN;
reg->loc.fn = arm_dwarf2_prev_register;
break;
case ARM_SP_REGNUM:
reg->how = DWARF2_FRAME_REG_CFA;
break;
}
}
/* When arguments must be pushed onto the stack, they go on in reverse
order. The code below implements a FILO (stack) to do this. */
struct stack_item
{
int len;
struct stack_item *prev;
void *data;
};
static struct stack_item *
push_stack_item (struct stack_item *prev, void *contents, int len)
{
struct stack_item *si;
si = xmalloc (sizeof (struct stack_item));
si->data = xmalloc (len);
si->len = len;
si->prev = prev;
memcpy (si->data, contents, len);
return si;
}
static struct stack_item *
pop_stack_item (struct stack_item *si)
{
struct stack_item *dead = si;
si = si->prev;
xfree (dead->data);
xfree (dead);
return si;
}
/* Return the alignment (in bytes) of the given type. */
static int
arm_type_align (struct type *t)
{
int n;
int align;
int falign;
t = check_typedef (t);
switch (TYPE_CODE (t))
{
default:
/* Should never happen. */
internal_error (__FILE__, __LINE__, _("unknown type alignment"));
return 4;
case TYPE_CODE_PTR:
case TYPE_CODE_ENUM:
case TYPE_CODE_INT:
case TYPE_CODE_FLT:
case TYPE_CODE_SET:
case TYPE_CODE_RANGE:
case TYPE_CODE_BITSTRING:
case TYPE_CODE_REF:
case TYPE_CODE_CHAR:
case TYPE_CODE_BOOL:
return TYPE_LENGTH (t);
case TYPE_CODE_ARRAY:
case TYPE_CODE_COMPLEX:
/* TODO: What about vector types? */
return arm_type_align (TYPE_TARGET_TYPE (t));
case TYPE_CODE_STRUCT:
case TYPE_CODE_UNION:
align = 1;
for (n = 0; n < TYPE_NFIELDS (t); n++)
{
falign = arm_type_align (TYPE_FIELD_TYPE (t, n));
if (falign > align)
align = falign;
}
return align;
}
}
/* Possible base types for a candidate for passing and returning in
VFP registers. */
enum arm_vfp_cprc_base_type
{
VFP_CPRC_UNKNOWN,
VFP_CPRC_SINGLE,
VFP_CPRC_DOUBLE,
VFP_CPRC_VEC64,
VFP_CPRC_VEC128
};
/* The length of one element of base type B. */
static unsigned
arm_vfp_cprc_unit_length (enum arm_vfp_cprc_base_type b)
{
switch (b)
{
case VFP_CPRC_SINGLE:
return 4;
case VFP_CPRC_DOUBLE:
return 8;
case VFP_CPRC_VEC64:
return 8;
case VFP_CPRC_VEC128:
return 16;
default:
internal_error (__FILE__, __LINE__, _("Invalid VFP CPRC type: %d."),
(int) b);
}
}
/* The character ('s', 'd' or 'q') for the type of VFP register used
for passing base type B. */
static int
arm_vfp_cprc_reg_char (enum arm_vfp_cprc_base_type b)
{
switch (b)
{
case VFP_CPRC_SINGLE:
return 's';
case VFP_CPRC_DOUBLE:
return 'd';
case VFP_CPRC_VEC64:
return 'd';
case VFP_CPRC_VEC128:
return 'q';
default:
internal_error (__FILE__, __LINE__, _("Invalid VFP CPRC type: %d."),
(int) b);
}
}
/* Determine whether T may be part of a candidate for passing and
returning in VFP registers, ignoring the limit on the total number
of components. If *BASE_TYPE is VFP_CPRC_UNKNOWN, set it to the
classification of the first valid component found; if it is not
VFP_CPRC_UNKNOWN, all components must have the same classification
as *BASE_TYPE. If it is found that T contains a type not permitted
for passing and returning in VFP registers, a type differently
classified from *BASE_TYPE, or two types differently classified
from each other, return -1, otherwise return the total number of
base-type elements found (possibly 0 in an empty structure or
array). Vectors and complex types are not currently supported,
matching the generic AAPCS support. */
static int
arm_vfp_cprc_sub_candidate (struct type *t,
enum arm_vfp_cprc_base_type *base_type)
{
t = check_typedef (t);
switch (TYPE_CODE (t))
{
case TYPE_CODE_FLT:
switch (TYPE_LENGTH (t))
{
case 4:
if (*base_type == VFP_CPRC_UNKNOWN)
*base_type = VFP_CPRC_SINGLE;
else if (*base_type != VFP_CPRC_SINGLE)
return -1;
return 1;
case 8:
if (*base_type == VFP_CPRC_UNKNOWN)
*base_type = VFP_CPRC_DOUBLE;
else if (*base_type != VFP_CPRC_DOUBLE)
return -1;
return 1;
default:
return -1;
}
break;
case TYPE_CODE_ARRAY:
{
int count;
unsigned unitlen;
count = arm_vfp_cprc_sub_candidate (TYPE_TARGET_TYPE (t), base_type);
if (count == -1)
return -1;
if (TYPE_LENGTH (t) == 0)
{
gdb_assert (count == 0);
return 0;
}
else if (count == 0)
return -1;
unitlen = arm_vfp_cprc_unit_length (*base_type);
gdb_assert ((TYPE_LENGTH (t) % unitlen) == 0);
return TYPE_LENGTH (t) / unitlen;
}
break;
case TYPE_CODE_STRUCT:
{
int count = 0;
unsigned unitlen;
int i;
for (i = 0; i < TYPE_NFIELDS (t); i++)
{
int sub_count = arm_vfp_cprc_sub_candidate (TYPE_FIELD_TYPE (t, i),
base_type);
if (sub_count == -1)
return -1;
count += sub_count;
}
if (TYPE_LENGTH (t) == 0)
{
gdb_assert (count == 0);
return 0;
}
else if (count == 0)
return -1;
unitlen = arm_vfp_cprc_unit_length (*base_type);
if (TYPE_LENGTH (t) != unitlen * count)
return -1;
return count;
}
case TYPE_CODE_UNION:
{
int count = 0;
unsigned unitlen;
int i;
for (i = 0; i < TYPE_NFIELDS (t); i++)
{
int sub_count = arm_vfp_cprc_sub_candidate (TYPE_FIELD_TYPE (t, i),
base_type);
if (sub_count == -1)
return -1;
count = (count > sub_count ? count : sub_count);
}
if (TYPE_LENGTH (t) == 0)
{
gdb_assert (count == 0);
return 0;
}
else if (count == 0)
return -1;
unitlen = arm_vfp_cprc_unit_length (*base_type);
if (TYPE_LENGTH (t) != unitlen * count)
return -1;
return count;
}
default:
break;
}
return -1;
}
/* Determine whether T is a VFP co-processor register candidate (CPRC)
if passed to or returned from a non-variadic function with the VFP
ABI in effect. Return 1 if it is, 0 otherwise. If it is, set
*BASE_TYPE to the base type for T and *COUNT to the number of
elements of that base type before returning. */
static int
arm_vfp_call_candidate (struct type *t, enum arm_vfp_cprc_base_type *base_type,
int *count)
{
enum arm_vfp_cprc_base_type b = VFP_CPRC_UNKNOWN;
int c = arm_vfp_cprc_sub_candidate (t, &b);
if (c <= 0 || c > 4)
return 0;
*base_type = b;
*count = c;
return 1;
}
/* Return 1 if the VFP ABI should be used for passing arguments to and
returning values from a function of type FUNC_TYPE, 0
otherwise. */
static int
arm_vfp_abi_for_function (struct gdbarch *gdbarch, struct type *func_type)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* Variadic functions always use the base ABI. Assume that functions
without debug info are not variadic. */
if (func_type && TYPE_VARARGS (check_typedef (func_type)))
return 0;
/* The VFP ABI is only supported as a variant of AAPCS. */
if (tdep->arm_abi != ARM_ABI_AAPCS)
return 0;
return gdbarch_tdep (gdbarch)->fp_model == ARM_FLOAT_VFP;
}
/* We currently only support passing parameters in integer registers, which
conforms with GCC's default model, and VFP argument passing following
the VFP variant of AAPCS. Several other variants exist and
we should probably support some of them based on the selected ABI. */
static CORE_ADDR
arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
struct value **args, CORE_ADDR sp, int struct_return,
CORE_ADDR struct_addr)
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
int argnum;
int argreg;
int nstack;
struct stack_item *si = NULL;
int use_vfp_abi;
struct type *ftype;
unsigned vfp_regs_free = (1 << 16) - 1;
/* Determine the type of this function and whether the VFP ABI
applies. */
ftype = check_typedef (value_type (function));
if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
use_vfp_abi = arm_vfp_abi_for_function (gdbarch, ftype);
/* Set the return address. For the ARM, the return breakpoint is
always at BP_ADDR. */
/* XXX Fix for Thumb. */
regcache_cooked_write_unsigned (regcache, ARM_LR_REGNUM, bp_addr);
/* Walk through the list of args and determine how large a temporary
stack is required. Need to take care here as structs may be
passed on the stack, and we have to to push them. */
nstack = 0;
argreg = ARM_A1_REGNUM;
nstack = 0;
/* The struct_return pointer occupies the first parameter
passing register. */
if (struct_return)
{
if (arm_debug)
fprintf_unfiltered (gdb_stdlog, "struct return in %s = %s\n",
gdbarch_register_name (gdbarch, argreg),
paddress (gdbarch, struct_addr));
regcache_cooked_write_unsigned (regcache, argreg, struct_addr);
argreg++;
}
for (argnum = 0; argnum < nargs; argnum++)
{
int len;
struct type *arg_type;
struct type *target_type;
enum type_code typecode;
bfd_byte *val;
int align;
enum arm_vfp_cprc_base_type vfp_base_type;
int vfp_base_count;
int may_use_core_reg = 1;
arg_type = check_typedef (value_type (args[argnum]));
len = TYPE_LENGTH (arg_type);
target_type = TYPE_TARGET_TYPE (arg_type);
typecode = TYPE_CODE (arg_type);
val = value_contents_writeable (args[argnum]);
align = arm_type_align (arg_type);
/* Round alignment up to a whole number of words. */
align = (align + INT_REGISTER_SIZE - 1) & ~(INT_REGISTER_SIZE - 1);
/* Different ABIs have different maximum alignments. */
if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_APCS)
{
/* The APCS ABI only requires word alignment. */
align = INT_REGISTER_SIZE;
}
else
{
/* The AAPCS requires at most doubleword alignment. */
if (align > INT_REGISTER_SIZE * 2)
align = INT_REGISTER_SIZE * 2;
}
if (use_vfp_abi
&& arm_vfp_call_candidate (arg_type, &vfp_base_type,
&vfp_base_count))
{
int regno;
int unit_length;
int shift;
unsigned mask;
/* Because this is a CPRC it cannot go in a core register or
cause a core register to be skipped for alignment.
Either it goes in VFP registers and the rest of this loop
iteration is skipped for this argument, or it goes on the
stack (and the stack alignment code is correct for this
case). */
may_use_core_reg = 0;
unit_length = arm_vfp_cprc_unit_length (vfp_base_type);
shift = unit_length / 4;
mask = (1 << (shift * vfp_base_count)) - 1;
for (regno = 0; regno < 16; regno += shift)
if (((vfp_regs_free >> regno) & mask) == mask)
break;
if (regno < 16)
{
int reg_char;
int reg_scaled;
int i;
vfp_regs_free &= ~(mask << regno);
reg_scaled = regno / shift;
reg_char = arm_vfp_cprc_reg_char (vfp_base_type);
for (i = 0; i < vfp_base_count; i++)
{
char name_buf[4];
int regnum;
if (reg_char == 'q')
arm_neon_quad_write (gdbarch, regcache, reg_scaled + i,
val + i * unit_length);
else
{
sprintf (name_buf, "%c%d", reg_char, reg_scaled + i);
regnum = user_reg_map_name_to_regnum (gdbarch, name_buf,
strlen (name_buf));
regcache_cooked_write (regcache, regnum,
val + i * unit_length);
}
}
continue;
}
else
{
/* This CPRC could not go in VFP registers, so all VFP
registers are now marked as used. */
vfp_regs_free = 0;
}
}
/* Push stack padding for dowubleword alignment. */
if (nstack & (align - 1))
{
si = push_stack_item (si, val, INT_REGISTER_SIZE);
nstack += INT_REGISTER_SIZE;
}
/* Doubleword aligned quantities must go in even register pairs. */
if (may_use_core_reg
&& argreg <= ARM_LAST_ARG_REGNUM
&& align > INT_REGISTER_SIZE
&& argreg & 1)
argreg++;
/* If the argument is a pointer to a function, and it is a
Thumb function, create a LOCAL copy of the value and set
the THUMB bit in it. */
if (TYPE_CODE_PTR == typecode
&& target_type != NULL
&& TYPE_CODE_FUNC == TYPE_CODE (target_type))
{
CORE_ADDR regval = extract_unsigned_integer (val, len, byte_order);
if (arm_pc_is_thumb (regval))
{
val = alloca (len);
store_unsigned_integer (val, len, byte_order,
MAKE_THUMB_ADDR (regval));
}
}
/* Copy the argument to general registers or the stack in
register-sized pieces. Large arguments are split between
registers and stack. */
while (len > 0)
{
int partial_len = len < INT_REGISTER_SIZE ? len : INT_REGISTER_SIZE;
if (may_use_core_reg && argreg <= ARM_LAST_ARG_REGNUM)
{
/* The argument is being passed in a general purpose
register. */
CORE_ADDR regval
= extract_unsigned_integer (val, partial_len, byte_order);
if (byte_order == BFD_ENDIAN_BIG)
regval <<= (INT_REGISTER_SIZE - partial_len) * 8;
if (arm_debug)
fprintf_unfiltered (gdb_stdlog, "arg %d in %s = 0x%s\n",
argnum,
gdbarch_register_name
(gdbarch, argreg),
phex (regval, INT_REGISTER_SIZE));
regcache_cooked_write_unsigned (regcache, argreg, regval);
argreg++;
}
else
{
/* Push the arguments onto the stack. */
if (arm_debug)
fprintf_unfiltered (gdb_stdlog, "arg %d @ sp + %d\n",
argnum, nstack);
si = push_stack_item (si, val, INT_REGISTER_SIZE);
nstack += INT_REGISTER_SIZE;
}
len -= partial_len;
val += partial_len;
}
}
/* If we have an odd number of words to push, then decrement the stack
by one word now, so first stack argument will be dword aligned. */
if (nstack & 4)
sp -= 4;
while (si)
{
sp -= si->len;
write_memory (sp, si->data, si->len);
si = pop_stack_item (si);
}
/* Finally, update teh SP register. */
regcache_cooked_write_unsigned (regcache, ARM_SP_REGNUM, sp);
return sp;
}
/* Always align the frame to an 8-byte boundary. This is required on
some platforms and harmless on the rest. */
static CORE_ADDR
arm_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
{
/* Align the stack to eight bytes. */
return sp & ~ (CORE_ADDR) 7;
}
static void
print_fpu_flags (int flags)
{
if (flags & (1 << 0))
fputs ("IVO ", stdout);
if (flags & (1 << 1))
fputs ("DVZ ", stdout);
if (flags & (1 << 2))
fputs ("OFL ", stdout);
if (flags & (1 << 3))
fputs ("UFL ", stdout);
if (flags & (1 << 4))
fputs ("INX ", stdout);
putchar ('\n');
}
/* Print interesting information about the floating point processor
(if present) or emulator. */
static void
arm_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
struct frame_info *frame, const char *args)
{
unsigned long status = get_frame_register_unsigned (frame, ARM_FPS_REGNUM);
int type;
type = (status >> 24) & 127;
if (status & (1 << 31))
printf (_("Hardware FPU type %d\n"), type);
else
printf (_("Software FPU type %d\n"), type);
/* i18n: [floating point unit] mask */
fputs (_("mask: "), stdout);
print_fpu_flags (status >> 16);
/* i18n: [floating point unit] flags */
fputs (_("flags: "), stdout);
print_fpu_flags (status);
}
/* Construct the ARM extended floating point type. */
static struct type *
arm_ext_type (struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
if (!tdep->arm_ext_type)
tdep->arm_ext_type
= arch_float_type (gdbarch, -1, "builtin_type_arm_ext",
floatformats_arm_ext);
return tdep->arm_ext_type;
}
static struct type *
arm_neon_double_type (struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
if (tdep->neon_double_type == NULL)
{
struct type *t, *elem;
t = arch_composite_type (gdbarch, "__gdb_builtin_type_neon_d",
TYPE_CODE_UNION);
elem = builtin_type (gdbarch)->builtin_uint8;
append_composite_type_field (t, "u8", init_vector_type (elem, 8));
elem = builtin_type (gdbarch)->builtin_uint16;
append_composite_type_field (t, "u16", init_vector_type (elem, 4));
elem = builtin_type (gdbarch)->builtin_uint32;
append_composite_type_field (t, "u32", init_vector_type (elem, 2));
elem = builtin_type (gdbarch)->builtin_uint64;
append_composite_type_field (t, "u64", elem);
elem = builtin_type (gdbarch)->builtin_float;
append_composite_type_field (t, "f32", init_vector_type (elem, 2));
elem = builtin_type (gdbarch)->builtin_double;
append_composite_type_field (t, "f64", elem);
TYPE_VECTOR (t) = 1;
TYPE_NAME (t) = "neon_d";
tdep->neon_double_type = t;
}
return tdep->neon_double_type;
}
/* FIXME: The vector types are not correctly ordered on big-endian
targets. Just as s0 is the low bits of d0, d0[0] is also the low
bits of d0 - regardless of what unit size is being held in d0. So
the offset of the first uint8 in d0 is 7, but the offset of the
first float is 4. This code works as-is for little-endian
targets. */
static struct type *
arm_neon_quad_type (struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
if (tdep->neon_quad_type == NULL)
{
struct type *t, *elem;
t = arch_composite_type (gdbarch, "__gdb_builtin_type_neon_q",
TYPE_CODE_UNION);
elem = builtin_type (gdbarch)->builtin_uint8;
append_composite_type_field (t, "u8", init_vector_type (elem, 16));
elem = builtin_type (gdbarch)->builtin_uint16;
append_composite_type_field (t, "u16", init_vector_type (elem, 8));
elem = builtin_type (gdbarch)->builtin_uint32;
append_composite_type_field (t, "u32", init_vector_type (elem, 4));
elem = builtin_type (gdbarch)->builtin_uint64;
append_composite_type_field (t, "u64", init_vector_type (elem, 2));
elem = builtin_type (gdbarch)->builtin_float;
append_composite_type_field (t, "f32", init_vector_type (elem, 4));
elem = builtin_type (gdbarch)->builtin_double;
append_composite_type_field (t, "f64", init_vector_type (elem, 2));
TYPE_VECTOR (t) = 1;
TYPE_NAME (t) = "neon_q";
tdep->neon_quad_type = t;
}
return tdep->neon_quad_type;
}
/* Return the GDB type object for the "standard" data type of data in
register N. */
static struct type *
arm_register_type (struct gdbarch *gdbarch, int regnum)
{
int num_regs = gdbarch_num_regs (gdbarch);
if (gdbarch_tdep (gdbarch)->have_vfp_pseudos
&& regnum >= num_regs && regnum < num_regs + 32)
return builtin_type (gdbarch)->builtin_float;
if (gdbarch_tdep (gdbarch)->have_neon_pseudos
&& regnum >= num_regs + 32 && regnum < num_regs + 32 + 16)
return arm_neon_quad_type (gdbarch);
/* If the target description has register information, we are only
in this function so that we can override the types of
double-precision registers for NEON. */
if (tdesc_has_registers (gdbarch_target_desc (gdbarch)))
{
struct type *t = tdesc_register_type (gdbarch, regnum);
if (regnum >= ARM_D0_REGNUM && regnum < ARM_D0_REGNUM + 32
&& TYPE_CODE (t) == TYPE_CODE_FLT
&& gdbarch_tdep (gdbarch)->have_neon)
return arm_neon_double_type (gdbarch);
else
return t;
}
if (regnum >= ARM_F0_REGNUM && regnum < ARM_F0_REGNUM + NUM_FREGS)
{
if (!gdbarch_tdep (gdbarch)->have_fpa_registers)
return builtin_type (gdbarch)->builtin_void;
return arm_ext_type (gdbarch);
}
else if (regnum == ARM_SP_REGNUM)
return builtin_type (gdbarch)->builtin_data_ptr;
else if (regnum == ARM_PC_REGNUM)
return builtin_type (gdbarch)->builtin_func_ptr;
else if (regnum >= ARRAY_SIZE (arm_register_names))
/* These registers are only supported on targets which supply
an XML description. */
return builtin_type (gdbarch)->builtin_int0;
else
return builtin_type (gdbarch)->builtin_uint32;
}
/* Map a DWARF register REGNUM onto the appropriate GDB register
number. */
static int
arm_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
{
/* Core integer regs. */
if (reg >= 0 && reg <= 15)
return reg;
/* Legacy FPA encoding. These were once used in a way which
overlapped with VFP register numbering, so their use is
discouraged, but GDB doesn't support the ARM toolchain
which used them for VFP. */
if (reg >= 16 && reg <= 23)
return ARM_F0_REGNUM + reg - 16;
/* New assignments for the FPA registers. */
if (reg >= 96 && reg <= 103)
return ARM_F0_REGNUM + reg - 96;
/* WMMX register assignments. */
if (reg >= 104 && reg <= 111)
return ARM_WCGR0_REGNUM + reg - 104;
if (reg >= 112 && reg <= 127)
return ARM_WR0_REGNUM + reg - 112;
if (reg >= 192 && reg <= 199)
return ARM_WC0_REGNUM + reg - 192;
/* VFP v2 registers. A double precision value is actually
in d1 rather than s2, but the ABI only defines numbering
for the single precision registers. This will "just work"
in GDB for little endian targets (we'll read eight bytes,
starting in s0 and then progressing to s1), but will be
reversed on big endian targets with VFP. This won't
be a problem for the new Neon quad registers; you're supposed
to use DW_OP_piece for those. */
if (reg >= 64 && reg <= 95)
{
char name_buf[4];
sprintf (name_buf, "s%d", reg - 64);
return user_reg_map_name_to_regnum (gdbarch, name_buf,
strlen (name_buf));
}
/* VFP v3 / Neon registers. This range is also used for VFP v2
registers, except that it now describes d0 instead of s0. */
if (reg >= 256 && reg <= 287)
{
char name_buf[4];
sprintf (name_buf, "d%d", reg - 256);
return user_reg_map_name_to_regnum (gdbarch, name_buf,
strlen (name_buf));
}
return -1;
}
/* Map GDB internal REGNUM onto the Arm simulator register numbers. */
static int
arm_register_sim_regno (struct gdbarch *gdbarch, int regnum)
{
int reg = regnum;
gdb_assert (reg >= 0 && reg < gdbarch_num_regs (gdbarch));
if (regnum >= ARM_WR0_REGNUM && regnum <= ARM_WR15_REGNUM)
return regnum - ARM_WR0_REGNUM + SIM_ARM_IWMMXT_COP0R0_REGNUM;
if (regnum >= ARM_WC0_REGNUM && regnum <= ARM_WC7_REGNUM)
return regnum - ARM_WC0_REGNUM + SIM_ARM_IWMMXT_COP1R0_REGNUM;
if (regnum >= ARM_WCGR0_REGNUM && regnum <= ARM_WCGR7_REGNUM)
return regnum - ARM_WCGR0_REGNUM + SIM_ARM_IWMMXT_COP1R8_REGNUM;
if (reg < NUM_GREGS)
return SIM_ARM_R0_REGNUM + reg;
reg -= NUM_GREGS;
if (reg < NUM_FREGS)
return SIM_ARM_FP0_REGNUM + reg;
reg -= NUM_FREGS;
if (reg < NUM_SREGS)
return SIM_ARM_FPS_REGNUM + reg;
reg -= NUM_SREGS;
internal_error (__FILE__, __LINE__, _("Bad REGNUM %d"), regnum);
}
/* NOTE: cagney/2001-08-20: Both convert_from_extended() and
convert_to_extended() use floatformat_arm_ext_littlebyte_bigword.
It is thought that this is is the floating-point register format on
little-endian systems. */
static void
convert_from_extended (const struct floatformat *fmt, const void *ptr,
void *dbl, int endianess)
{
DOUBLEST d;
if (endianess == BFD_ENDIAN_BIG)
floatformat_to_doublest (&floatformat_arm_ext_big, ptr, &d);
else
floatformat_to_doublest (&floatformat_arm_ext_littlebyte_bigword,
ptr, &d);
floatformat_from_doublest (fmt, &d, dbl);
}
static void
convert_to_extended (const struct floatformat *fmt, void *dbl, const void *ptr,
int endianess)
{
DOUBLEST d;
floatformat_to_doublest (fmt, ptr, &d);
if (endianess == BFD_ENDIAN_BIG)
floatformat_from_doublest (&floatformat_arm_ext_big, &d, dbl);
else
floatformat_from_doublest (&floatformat_arm_ext_littlebyte_bigword,
&d, dbl);
}
static 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;
}
/* Support routines for single stepping. Calculate the next PC value. */
#define submask(x) ((1L << ((x) + 1)) - 1)
#define bit(obj,st) (((obj) >> (st)) & 1)
#define bits(obj,st,fn) (((obj) >> (st)) & submask ((fn) - (st)))
#define sbits(obj,st,fn) \
((long) (bits(obj,st,fn) | ((long) bit(obj,fn) * ~ submask (fn - st))))
#define BranchDest(addr,instr) \
((CORE_ADDR) (((long) (addr)) + 8 + (sbits (instr, 0, 23) << 2)))
#define ARM_PC_32 1
static unsigned long
shifted_reg_val (struct frame_info *frame, 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
: get_frame_register_unsigned (frame, rs)) & 0xFF;
}
else
shift = bits (inst, 7, 11);
res = (rm == 15
? ((pc_val | (ARM_PC_32 ? 0 : status_reg))
+ (bit (inst, 4) ? 12 : 8))
: get_frame_register_unsigned (frame, 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;
}
/* Return number of 1-bits in VAL. */
static int
bitcount (unsigned long val)
{
int nbits;
for (nbits = 0; val != 0; nbits++)
val &= val - 1; /* delete rightmost 1-bit in val */
return nbits;
}
static CORE_ADDR
thumb_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
unsigned long pc_val = ((unsigned long) pc) + 4; /* PC after prefetch */
unsigned short inst1;
CORE_ADDR nextpc = pc + 2; /* default is next instruction */
unsigned long offset;
inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
if ((inst1 & 0xff00) == 0xbd00) /* pop {rlist, pc} */
{
CORE_ADDR sp;
/* Fetch the saved PC from the stack. It's stored above
all of the other registers. */
offset = bitcount (bits (inst1, 0, 7)) * INT_REGISTER_SIZE;
sp = get_frame_register_unsigned (frame, ARM_SP_REGNUM);
nextpc = read_memory_unsigned_integer (sp + offset, 4, byte_order);
nextpc = gdbarch_addr_bits_remove (gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
}
else if ((inst1 & 0xf000) == 0xd000) /* conditional branch */
{
unsigned long status = get_frame_register_unsigned (frame, ARM_PS_REGNUM);
unsigned long cond = bits (inst1, 8, 11);
if (cond != 0x0f && condition_true (cond, status)) /* 0x0f = SWI */
nextpc = pc_val + (sbits (inst1, 0, 7) << 1);
}
else if ((inst1 & 0xf800) == 0xe000) /* unconditional branch */
{
nextpc = pc_val + (sbits (inst1, 0, 10) << 1);
}
else if ((inst1 & 0xf800) == 0xf000) /* long branch with link, and blx */
{
unsigned short inst2;
inst2 = read_memory_unsigned_integer (pc + 2, 2, byte_order_for_code);
offset = (sbits (inst1, 0, 10) << 12) + (bits (inst2, 0, 10) << 1);
nextpc = pc_val + offset;
/* For BLX make sure to clear the low bits. */
if (bits (inst2, 11, 12) == 1)
nextpc = nextpc & 0xfffffffc;
}
else if ((inst1 & 0xff00) == 0x4700) /* bx REG, blx REG */
{
if (bits (inst1, 3, 6) == 0x0f)
nextpc = pc_val;
else
nextpc = get_frame_register_unsigned (frame, bits (inst1, 3, 6));
nextpc = gdbarch_addr_bits_remove (gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
}
return nextpc;
}
CORE_ADDR
arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
unsigned long pc_val;
unsigned long this_instr;
unsigned long status;
CORE_ADDR nextpc;
if (arm_frame_is_thumb (frame))
return thumb_get_next_pc (frame, pc);
pc_val = (unsigned long) pc;
this_instr = read_memory_unsigned_integer (pc, 4, byte_order_for_code);
status = get_frame_register_unsigned (frame, ARM_PS_REGNUM);
nextpc = (CORE_ADDR) (pc_val + 4); /* Default case */
if (bits (this_instr, 28, 31) == INST_NV)
switch (bits (this_instr, 24, 27))
{
case 0xa:
case 0xb:
{
/* Branch with Link and change to Thumb. */
nextpc = BranchDest (pc, this_instr);
nextpc |= bit (this_instr, 24) << 1;
nextpc = gdbarch_addr_bits_remove (gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
break;
}
case 0xc:
case 0xd:
case 0xe:
/* Coprocessor register transfer. */
if (bits (this_instr, 12, 15) == 15)
error (_("Invalid update to pc in instruction"));
break;
}
else if (condition_true (bits (this_instr, 28, 31), status))
{
switch (bits (this_instr, 24, 27))
{
case 0x0:
case 0x1: /* data processing */
case 0x2:
case 0x3:
{
unsigned long operand1, operand2, result = 0;
unsigned long rn;
int c;
if (bits (this_instr, 12, 15) != 15)
break;
if (bits (this_instr, 22, 25) == 0
&& bits (this_instr, 4, 7) == 9) /* multiply */
error (_("Invalid update to pc in instruction"));
/* BX , BLX */
if (bits (this_instr, 4, 27) == 0x12fff1
|| bits (this_instr, 4, 27) == 0x12fff3)
{
rn = bits (this_instr, 0, 3);
result = (rn == 15) ? pc_val + 8
: get_frame_register_unsigned (frame, rn);
nextpc = (CORE_ADDR) gdbarch_addr_bits_remove
(gdbarch, result);
if (nextpc == pc)
error (_("Infinite loop detected"));
return nextpc;
}
/* Multiply into PC */
c = (status & FLAG_C) ? 1 : 0;
rn = bits (this_instr, 16, 19);
operand1 = (rn == 15) ? pc_val + 8
: get_frame_register_unsigned (frame, rn);
if (bit (this_instr, 25))
{
unsigned long immval = bits (this_instr, 0, 7);
unsigned long rotate = 2 * bits (this_instr, 8, 11);
operand2 = ((immval >> rotate) | (immval << (32 - rotate)))
& 0xffffffff;
}
else /* operand 2 is a shifted register */
operand2 = shifted_reg_val (frame, this_instr, c, pc_val, status);
switch (bits (this_instr, 21, 24))
{
case 0x0: /*and */
result = operand1 & operand2;
break;
case 0x1: /*eor */
result = operand1 ^ operand2;
break;
case 0x2: /*sub */
result = operand1 - operand2;
break;
case 0x3: /*rsb */
result = operand2 - operand1;
break;
case 0x4: /*add */
result = operand1 + operand2;
break;
case 0x5: /*adc */
result = operand1 + operand2 + c;
break;
case 0x6: /*sbc */
result = operand1 - operand2 + c;
break;
case 0x7: /*rsc */
result = operand2 - operand1 + c;
break;
case 0x8:
case 0x9:
case 0xa:
case 0xb: /* tst, teq, cmp, cmn */
result = (unsigned long) nextpc;
break;
case 0xc: /*orr */
result = operand1 | operand2;
break;
case 0xd: /*mov */
/* Always step into a function. */
result = operand2;
break;
case 0xe: /*bic */
result = operand1 & ~operand2;
break;
case 0xf: /*mvn */
result = ~operand2;
break;
}
nextpc = (CORE_ADDR) gdbarch_addr_bits_remove
(gdbarch, result);
if (nextpc == pc)
error (_("Infinite loop detected"));
break;
}
case 0x4:
case 0x5: /* data transfer */
case 0x6:
case 0x7:
if (bit (this_instr, 20))
{
/* load */
if (bits (this_instr, 12, 15) == 15)
{
/* rd == pc */
unsigned long rn;
unsigned long base;
if (bit (this_instr, 22))
error (_("Invalid update to pc in instruction"));
/* byte write to PC */
rn = bits (this_instr, 16, 19);
base = (rn == 15) ? pc_val + 8
: get_frame_register_unsigned (frame, rn);
if (bit (this_instr, 24))
{
/* pre-indexed */
int c = (status & FLAG_C) ? 1 : 0;
unsigned long offset =
(bit (this_instr, 25)
? shifted_reg_val (frame, this_instr, c, pc_val, status)
: bits (this_instr, 0, 11));
if (bit (this_instr, 23))
base += offset;
else
base -= offset;
}
nextpc = (CORE_ADDR) read_memory_integer ((CORE_ADDR) base,
4, byte_order);
nextpc = gdbarch_addr_bits_remove (gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
}
}
break;
case 0x8:
case 0x9: /* block transfer */
if (bit (this_instr, 20))
{
/* LDM */
if (bit (this_instr, 15))
{
/* loading pc */
int offset = 0;
if (bit (this_instr, 23))
{
/* up */
unsigned long reglist = bits (this_instr, 0, 14);
offset = bitcount (reglist) * 4;
if (bit (this_instr, 24)) /* pre */
offset += 4;
}
else if (bit (this_instr, 24))
offset = -4;
{
unsigned long rn_val =
get_frame_register_unsigned (frame,
bits (this_instr, 16, 19));
nextpc =
(CORE_ADDR) read_memory_integer ((CORE_ADDR) (rn_val
+ offset),
4, byte_order);
}
nextpc = gdbarch_addr_bits_remove
(gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
}
}
break;
case 0xb: /* branch & link */
case 0xa: /* branch */
{
nextpc = BranchDest (pc, this_instr);
nextpc = gdbarch_addr_bits_remove (gdbarch, nextpc);
if (nextpc == pc)
error (_("Infinite loop detected"));
break;
}
case 0xc:
case 0xd:
case 0xe: /* coproc ops */
case 0xf: /* SWI */
break;
default:
fprintf_filtered (gdb_stderr, _("Bad bit-field extraction\n"));
return (pc);
}
}
return nextpc;
}
/* single_step() is called just before we want to resume the inferior,
if we want to single-step it but there is no hardware or kernel
single-step support. We find the target of the coming instruction
and breakpoint it. */
int
arm_software_single_step (struct frame_info *frame)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
/* NOTE: This may insert the wrong breakpoint instruction when
single-stepping over a mode-changing instruction, if the
CPSR heuristics are used. */
CORE_ADDR next_pc = arm_get_next_pc (frame, get_frame_pc (frame));
insert_single_step_breakpoint (gdbarch, next_pc);
return 1;
}
/* ARM displaced stepping support.
Generally ARM displaced stepping works as follows:
1. When an instruction is to be single-stepped, it is first decoded by
arm_process_displaced_insn (called from arm_displaced_step_copy_insn).
Depending on the type of instruction, it is then copied to a scratch
location, possibly in a modified form. The copy_* set of functions
performs such modification, as necessary. A breakpoint is placed after
the modified instruction in the scratch space to return control to GDB.
Note in particular that instructions which modify the PC will no longer
do so after modification.
2. The instruction is single-stepped, by setting the PC to the scratch
location address, and resuming. Control returns to GDB when the
breakpoint is hit.
3. A cleanup function (cleanup_*) is called corresponding to the copy_*
function used for the current instruction. This function's job is to
put the CPU/memory state back to what it would have been if the
instruction had been executed unmodified in its original location. */
/* NOP instruction (mov r0, r0). */
#define ARM_NOP 0xe1a00000
/* Helper for register reads for displaced stepping. In particular, this
returns the PC as it would be seen by the instruction at its original
location. */
ULONGEST
displaced_read_reg (struct regcache *regs, CORE_ADDR from, int regno)
{
ULONGEST ret;
if (regno == 15)
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: read pc value %.8lx\n",
(unsigned long) from + 8);
return (ULONGEST) from + 8; /* Pipeline offset. */
}
else
{
regcache_cooked_read_unsigned (regs, regno, &ret);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: read r%d value %.8lx\n",
regno, (unsigned long) ret);
return ret;
}
}
static int
displaced_in_arm_mode (struct regcache *regs)
{
ULONGEST ps;
regcache_cooked_read_unsigned (regs, ARM_PS_REGNUM, &ps);
return (ps & CPSR_T) == 0;
}
/* Write to the PC as from a branch instruction. */
static void
branch_write_pc (struct regcache *regs, ULONGEST val)
{
if (displaced_in_arm_mode (regs))
/* Note: If bits 0/1 are set, this branch would be unpredictable for
architecture versions < 6. */
regcache_cooked_write_unsigned (regs, ARM_PC_REGNUM, val & ~(ULONGEST) 0x3);
else
regcache_cooked_write_unsigned (regs, ARM_PC_REGNUM, val & ~(ULONGEST) 0x1);
}
/* Write to the PC as from a branch-exchange instruction. */
static void
bx_write_pc (struct regcache *regs, ULONGEST val)
{
ULONGEST ps;
regcache_cooked_read_unsigned (regs, ARM_PS_REGNUM, &ps);
if ((val & 1) == 1)
{
regcache_cooked_write_unsigned (regs, ARM_PS_REGNUM, ps | CPSR_T);
regcache_cooked_write_unsigned (regs, ARM_PC_REGNUM, val & 0xfffffffe);
}
else if ((val & 2) == 0)
{
regcache_cooked_write_unsigned (regs, ARM_PS_REGNUM,
ps & ~(ULONGEST) CPSR_T);
regcache_cooked_write_unsigned (regs, ARM_PC_REGNUM, val);
}
else
{
/* Unpredictable behaviour. Try to do something sensible (switch to ARM
mode, align dest to 4 bytes). */
warning (_("Single-stepping BX to non-word-aligned ARM instruction."));
regcache_cooked_write_unsigned (regs, ARM_PS_REGNUM,
ps & ~(ULONGEST) CPSR_T);
regcache_cooked_write_unsigned (regs, ARM_PC_REGNUM, val & 0xfffffffc);
}
}
/* Write to the PC as if from a load instruction. */
static void
load_write_pc (struct regcache *regs, ULONGEST val)
{
if (DISPLACED_STEPPING_ARCH_VERSION >= 5)
bx_write_pc (regs, val);
else
branch_write_pc (regs, val);
}
/* Write to the PC as if from an ALU instruction. */
static void
alu_write_pc (struct regcache *regs, ULONGEST val)
{
if (DISPLACED_STEPPING_ARCH_VERSION >= 7 && displaced_in_arm_mode (regs))
bx_write_pc (regs, val);
else
branch_write_pc (regs, val);
}
/* Helper for writing to registers for displaced stepping. Writing to the PC
has a varying effects depending on the instruction which does the write:
this is controlled by the WRITE_PC argument. */
void
displaced_write_reg (struct regcache *regs, struct displaced_step_closure *dsc,
int regno, ULONGEST val, enum pc_write_style write_pc)
{
if (regno == 15)
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: writing pc %.8lx\n",
(unsigned long) val);
switch (write_pc)
{
case BRANCH_WRITE_PC:
branch_write_pc (regs, val);
break;
case BX_WRITE_PC:
bx_write_pc (regs, val);
break;
case LOAD_WRITE_PC:
load_write_pc (regs, val);
break;
case ALU_WRITE_PC:
alu_write_pc (regs, val);
break;
case CANNOT_WRITE_PC:
warning (_("Instruction wrote to PC in an unexpected way when "
"single-stepping"));
break;
default:
internal_error (__FILE__, __LINE__,
_("Invalid argument to displaced_write_reg"));
}
dsc->wrote_to_pc = 1;
}
else
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: writing r%d value %.8lx\n",
regno, (unsigned long) val);
regcache_cooked_write_unsigned (regs, regno, val);
}
}
/* This function is used to concisely determine if an instruction INSN
references PC. Register fields of interest in INSN should have the
corresponding fields of BITMASK set to 0b1111. The function returns return 1
if any of these fields in INSN reference the PC (also 0b1111, r15), else it
returns 0. */
static int
insn_references_pc (uint32_t insn, uint32_t bitmask)
{
uint32_t lowbit = 1;
while (bitmask != 0)
{
uint32_t mask;
for (; lowbit && (bitmask & lowbit) == 0; lowbit <<= 1)
;
if (!lowbit)
break;
mask = lowbit * 0xf;
if ((insn & mask) == mask)
return 1;
bitmask &= ~mask;
}
return 0;
}
/* The simplest copy function. Many instructions have the same effect no
matter what address they are executed at: in those cases, use this. */
static int
copy_unmodified (struct gdbarch *gdbarch ATTRIBUTE_UNUSED, uint32_t insn,
const char *iname, struct displaced_step_closure *dsc)
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: copying insn %.8lx, "
"opcode/class '%s' unmodified\n", (unsigned long) insn,
iname);
dsc->modinsn[0] = insn;
return 0;
}
/* Preload instructions with immediate offset. */
static void
cleanup_preload (struct gdbarch *gdbarch ATTRIBUTE_UNUSED,
struct regcache *regs, struct displaced_step_closure *dsc)
{
displaced_write_reg (regs, dsc, 0, dsc->tmp[0], CANNOT_WRITE_PC);
if (!dsc->u.preload.immed)
displaced_write_reg (regs, dsc, 1, dsc->tmp[1], CANNOT_WRITE_PC);
}
static int
copy_preload (struct gdbarch *gdbarch, uint32_t insn, struct regcache *regs,
struct displaced_step_closure *dsc)
{
unsigned int rn = bits (insn, 16, 19);
ULONGEST rn_val;
CORE_ADDR from = dsc->insn_addr;
if (!insn_references_pc (insn, 0x000f0000ul))
return copy_unmodified (gdbarch, insn, "preload", dsc);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: copying preload insn %.8lx\n",
(unsigned long) insn);
/* Preload instructions:
{pli/pld} [rn, #+/-imm]
->
{pli/pld} [r0, #+/-imm]. */
dsc->tmp[0] = displaced_read_reg (regs, from, 0);
rn_val = displaced_read_reg (regs, from, rn);
displaced_write_reg (regs, dsc, 0, rn_val, CANNOT_WRITE_PC);
dsc->u.preload.immed = 1;
dsc->modinsn[0] = insn & 0xfff0ffff;
dsc->cleanup = &cleanup_preload;
return 0;
}
/* Preload instructions with register offset. */
static int
copy_preload_reg (struct gdbarch *gdbarch, uint32_t insn, struct regcache *regs,
struct displaced_step_closure *dsc)
{
unsigned int rn = bits (insn, 16, 19);
unsigned int rm = bits (insn, 0, 3);
ULONGEST rn_val, rm_val;
CORE_ADDR from = dsc->insn_addr;
if (!insn_references_pc (insn, 0x000f000ful))
return copy_unmodified (gdbarch, insn, "preload reg", dsc);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: copying preload insn %.8lx\n",
(unsigned long) insn);
/* Preload register-offset instructions:
{pli/pld} [rn, rm {, shift}]
->
{pli/pld} [r0, r1 {, shift}]. */
dsc->tmp[0] = displaced_read_reg (regs, from, 0);
dsc->tmp[1] = displaced_read_reg (regs, from, 1);
rn_val = displaced_read_reg (regs, from, rn);
rm_val = displaced_read_reg (regs, from, rm);
displaced_write_reg (regs, dsc, 0, rn_val, CANNOT_WRITE_PC);
displaced_write_reg (regs, dsc, 1, rm_val, CANNOT_WRITE_PC);
dsc->u.preload.immed = 0;
dsc->modinsn[0] = (insn & 0xfff0fff0) | 0x1;
dsc->cleanup = &cleanup_preload;
return 0;
}
/* Copy/cleanup coprocessor load and store instructions. */
static void
cleanup_copro_load_store (struct gdbarch *gdbarch ATTRIBUTE_UNUSED,
struct regcache *regs,
struct displaced_step_closure *dsc)
{
ULONGEST rn_val = displaced_read_reg (regs, dsc->insn_addr, 0);
displaced_write_reg (regs, dsc, 0, dsc->tmp[0], CANNOT_WRITE_PC);
if (dsc->u.ldst.writeback)
displaced_write_reg (regs, dsc, dsc->u.ldst.rn, rn_val, LOAD_WRITE_PC);
}
static int
copy_copro_load_store (struct gdbarch *gdbarch, uint32_t insn,
struct regcache *regs,
struct displaced_step_closure *dsc)
{
unsigned int rn = bits (insn, 16, 19);
ULONGEST rn_val;
CORE_ADDR from = dsc->insn_addr;
if (!insn_references_pc (insn, 0x000f0000ul))
return copy_unmodified (gdbarch, insn, "copro load/store", dsc);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: copying coprocessor "
"load/store insn %.8lx\n", (unsigned long) insn);
/* Coprocessor load/store instructions:
{stc/stc2} [, #+/-imm] (and other immediate addressing modes)
->
{stc/stc2} [r0, #+/-imm].
ldc/ldc2 are handled identically. */
dsc->tmp[0] = displaced_read_reg (regs, from, 0);
rn_val = displaced_read_reg (regs, from, rn);
displaced_write_reg (regs, dsc, 0, rn_val, CANNOT_WRITE_PC);
dsc->u.ldst.writeback = bit (insn, 25);
dsc->u.ldst.rn = rn;
dsc->modinsn[0] = insn & 0xfff0ffff;
dsc->cleanup = &cleanup_copro_load_store;
return 0;
}
/* Clean up branch instructions (actually perform the branch, by setting
PC). */
static void
cleanup_branch (struct gdbarch *gdbarch ATTRIBUTE_UNUSED, struct regcache *regs,
struct displaced_step_closure *dsc)
{
ULONGEST from = dsc->insn_addr;
uint32_t status = displaced_read_reg (regs, from, ARM_PS_REGNUM);
int branch_taken = condition_true (dsc->u.branch.cond, status);
enum pc_write_style write_pc = dsc->u.branch.exchange
? BX_WRITE_PC : BRANCH_WRITE_PC;
if (!branch_taken)
return;
if (dsc->u.branch.link)
{
ULONGEST pc = displaced_read_reg (regs, from, 15);
displaced_write_reg (regs, dsc, 14, pc - 4, CANNOT_WRITE_PC);
}
displaced_write_reg (regs, dsc, 15, dsc->u.branch.dest, write_pc);
}
/* Copy B/BL/BLX instructions with immediate destinations. */
static int
copy_b_bl_blx (struct gdbarch *gdbarch ATTRIBUTE_UNUSED, uint32_t insn,
struct regcache *regs, struct displaced_step_closure *dsc)
{
unsigned int cond = bits (insn, 28, 31);
int exchange = (cond == 0xf);
int link = exchange || bit (insn, 24);
CORE_ADDR from = dsc->insn_addr;
long offset;
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog, "displaced: copying %s immediate insn "
"%.8lx\n", (exchange) ? "blx" : (link) ? "bl" : "b",
(unsigned long) insn);
/* Implement "BL