X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=gdb%2Farm-tdep.c;h=1ac8817f282c02116196c7c26dd20e891dc24d0a;hb=e7fbb131d42983eec31231f8bb69cdd8d5a33ee6;hp=a7b62ddd14dead11c68efb1258619d4e357d82ce;hpb=60ade65d49ec4fd35e72823c786daf5043efca0a;p=binutils-gdb.git
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index a7b62ddd14d..1ac8817f282 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -1,13 +1,14 @@
/* 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 Free Software Foundation, Inc.
+ 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ 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 2 of the License, or
+ 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,
@@ -16,9 +17,7 @@
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, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ along with this program. If not, see . */
#include /* XXX for isupper () */
@@ -52,6 +51,7 @@
#include "elf/arm.h"
#include "gdb_assert.h"
+#include "vec.h"
static int arm_debug;
@@ -63,11 +63,26 @@ static int arm_debug;
MSYMBOL_IS_SPECIAL Tests the "special" bit in a minimal symbol. */
#define MSYMBOL_SET_SPECIAL(msym) \
- MSYMBOL_INFO (msym) = (char *) (((long) MSYMBOL_INFO (msym)) \
- | 0x80000000)
+ MSYMBOL_TARGET_FLAG_1 (msym) = 1
#define MSYMBOL_IS_SPECIAL(msym) \
- (((long) MSYMBOL_INFO (msym) & 0x80000000) != 0)
+ 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;
@@ -102,6 +117,17 @@ static const char *arm_abi_strings[] =
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;
@@ -178,9 +204,16 @@ static void set_disassembly_style_sfunc(char *, int,
static void set_disassembly_style (void);
static void convert_from_extended (const struct floatformat *, const void *,
- void *);
+ void *, int);
static void convert_to_extended (const struct floatformat *, void *,
- const 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
{
@@ -189,13 +222,11 @@ struct arm_prologue_cache
to identify this frame. */
CORE_ADDR prev_sp;
- /* The frame base for this frame is just prev_sp + frame offset -
- frame size. FRAMESIZE is the size of this stack frame, and
- FRAMEOFFSET if the initial offset from the stack pointer (this
- frame's stack pointer, not PREV_SP) to the frame base. */
+ /* 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;
- int frameoffset;
/* The register used to hold the frame pointer for this frame. */
int framereg;
@@ -204,6 +235,16 @@ struct arm_prologue_cache
struct trad_frame_saved_reg *saved_regs;
};
+static CORE_ADDR arm_analyze_prologue (struct gdbarch *gdbarch,
+ CORE_ADDR prologue_start,
+ CORE_ADDR prologue_end,
+ struct arm_prologue_cache *cache);
+
+/* 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)
@@ -214,36 +255,168 @@ struct arm_prologue_cache
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;
+}
+
+/* Search for the mapping symbol covering MEMADDR. If one is found,
+ return its type. Otherwise, return 0. If START is non-NULL,
+ set *START to the location of the mapping symbol. */
+
+static char
+arm_find_mapping_symbol (CORE_ADDR memaddr, CORE_ADDR *start)
+{
+ struct obj_section *sec;
+
+ /* 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)
+ {
+ if (start)
+ *start = map_sym->value + obj_section_addr (sec);
+ return map_sym->type;
+ }
+ }
+
+ if (idx > 0)
+ {
+ map_sym = VEC_index (arm_mapping_symbol_s, map, idx - 1);
+ if (start)
+ *start = map_sym->value + obj_section_addr (sec);
+ return map_sym->type;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+static CORE_ADDR arm_get_next_pc_raw (struct frame_info *frame,
+ CORE_ADDR pc, int insert_bkpt);
+
/* Determine if the program counter specified in MEMADDR is in a Thumb
- function. */
+ 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;
+ char type;
/* 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. */
+ type = arm_find_mapping_symbol (memaddr, NULL);
+ if (type)
+ return 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).
+
+ As a further heuristic if we detect that we are doing a single-step we
+ see what state executing the current instruction ends up with us being
+ in. */
+ if (target_has_registers)
{
- return (MSYMBOL_IS_SPECIAL (sym));
- }
- else
- {
- return 0;
+ struct frame_info *current_frame = get_current_frame ();
+ CORE_ADDR current_pc = get_frame_pc (current_frame);
+ int is_thumb = arm_frame_is_thumb (current_frame);
+ CORE_ADDR next_pc;
+ if (memaddr == current_pc)
+ return is_thumb;
+ else
+ {
+ struct gdbarch *gdbarch = get_frame_arch (current_frame);
+ next_pc = arm_get_next_pc_raw (current_frame, current_pc, FALSE);
+ if (memaddr == gdbarch_addr_bits_remove (gdbarch, next_pc))
+ return IS_THUMB_ADDR (next_pc);
+ else
+ return is_thumb;
+ }
}
+
+ /* 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 (CORE_ADDR val)
+arm_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val)
{
if (arm_apcs_32)
- return (val & (arm_pc_is_thumb (val) ? 0xfffffffe : 0xfffffffc));
+ return UNMAKE_THUMB_ADDR (val);
else
return (val & 0x03fffffc);
}
@@ -251,20 +424,65 @@ arm_addr_bits_remove (CORE_ADDR val)
/* 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 (CORE_ADDR val)
+arm_smash_text_address (struct gdbarch *gdbarch, CORE_ADDR val)
{
return val & ~1;
}
+/* Return 1 if PC is the start of a compiler helper function which
+ can be safely ignored during prologue skipping. */
+static int
+skip_prologue_function (CORE_ADDR pc)
+{
+ struct minimal_symbol *msym;
+ const char *name;
+
+ msym = lookup_minimal_symbol_by_pc (pc);
+ if (msym == NULL || SYMBOL_VALUE_ADDRESS (msym) != pc)
+ return 0;
+
+ name = SYMBOL_LINKAGE_NAME (msym);
+ if (name == NULL)
+ return 0;
+
+ /* The GNU linker's Thumb call stub to foo is named
+ __foo_from_thumb. */
+ if (strstr (name, "_from_thumb") != NULL)
+ name += 2;
+
+ /* On soft-float targets, __truncdfsf2 is called to convert promoted
+ arguments to their argument types in non-prototyped
+ functions. */
+ if (strncmp (name, "__truncdfsf2", strlen ("__truncdfsf2")) == 0)
+ return 1;
+ if (strncmp (name, "__aeabi_d2f", strlen ("__aeabi_d2f")) == 0)
+ return 1;
+
+ return 0;
+}
+
+/* Support routines for instruction parsing. */
+#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)))
+
/* 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. */
+ clobber the stack frame unexpectedly, or an unknown instruction.
+ Return the last address which is definitely safe to skip for an
+ initial breakpoint. */
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 = gdbarch_byte_order (gdbarch);
+ enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
int i;
pv_t regs[16];
struct pv_area *stack;
@@ -273,28 +491,22 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
for (i = 0; i < 16; i++)
regs[i] = pv_register (i, 0);
- stack = make_pv_area (ARM_SP_REGNUM);
+ stack = make_pv_area (ARM_SP_REGNUM, gdbarch_addr_bit (gdbarch));
back_to = make_cleanup_free_pv_area (stack);
- /* The call instruction saved PC in LR, and the current PC is not
- interesting. Due to this file's conventions, we want the value
- of LR at this function's entry, not at the call site, so we do
- not record the save of the PC - when the ARM prologue analyzer
- has also been converted to the pv mechanism, we could record the
- save here and remove the hack in prev_register. */
- regs[ARM_PC_REGNUM] = pv_unknown ();
-
while (start < limit)
{
unsigned short insn;
- insn = read_memory_unsigned_integer (start, 2);
+ insn = read_memory_unsigned_integer (start, 2, byte_order_for_code);
if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
{
int regno;
int mask;
- int stop = 0;
+
+ 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). */
@@ -304,19 +516,10 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
for (regno = ARM_LR_REGNUM; regno >= 0; regno--)
if (mask & (1 << regno))
{
- if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
- {
- stop = 1;
- break;
- }
-
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM],
-4);
pv_area_store (stack, regs[ARM_SP_REGNUM], 4, regs[regno]);
}
-
- if (stop)
- break;
}
else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR
sub sp, #simm */
@@ -329,9 +532,29 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
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 & 0xf800) == 0xa800) /* add Rd, sp, #imm */
+ regs[bits (insn, 8, 10)] = pv_add_constant (regs[ARM_SP_REGNUM],
+ (insn & 0xff) << 2);
+ else if ((insn & 0xfe00) == 0x1c00 /* add Rd, Rn, #imm */
+ && pv_is_register (regs[bits (insn, 3, 5)], ARM_SP_REGNUM))
+ regs[bits (insn, 0, 2)] = pv_add_constant (regs[bits (insn, 3, 5)],
+ bits (insn, 6, 8));
+ else if ((insn & 0xf800) == 0x3000 /* add Rd, #imm */
+ && pv_is_register (regs[bits (insn, 8, 10)], ARM_SP_REGNUM))
+ regs[bits (insn, 8, 10)] = pv_add_constant (regs[bits (insn, 8, 10)],
+ bits (insn, 0, 7));
+ else if ((insn & 0xfe00) == 0x1800 /* add Rd, Rn, Rm */
+ && pv_is_register (regs[bits (insn, 6, 8)], ARM_SP_REGNUM)
+ && pv_is_constant (regs[bits (insn, 3, 5)]))
+ regs[bits (insn, 0, 2)] = pv_add (regs[bits (insn, 3, 5)],
+ regs[bits (insn, 6, 8)]);
+ else if ((insn & 0xff00) == 0x4400 /* add Rd, Rm */
+ && pv_is_constant (regs[bits (insn, 3, 6)]))
+ {
+ int rd = (bit (insn, 7) << 3) + bits (insn, 0, 2);
+ int rm = bits (insn, 3, 6);
+ regs[rd] = pv_add (regs[rd], regs[rm]);
+ }
else if ((insn & 0xff00) == 0x4600) /* mov hi, lo or mov lo, hi */
{
int dst_reg = (insn & 0x7) + ((insn & 0x80) >> 4);
@@ -354,6 +577,131 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
pv_area_store (stack, addr, 4, regs[regno]);
}
+ else if ((insn & 0xf800) == 0x6000) /* str rd, [rn, #off] */
+ {
+ int rd = bits (insn, 0, 2);
+ int rn = bits (insn, 3, 5);
+ pv_t addr;
+
+ offset = bits (insn, 6, 10) << 2;
+ addr = pv_add_constant (regs[rn], offset);
+
+ if (pv_area_store_would_trash (stack, addr))
+ break;
+
+ pv_area_store (stack, addr, 4, regs[rd]);
+ }
+ else if (((insn & 0xf800) == 0x7000 /* strb Rd, [Rn, #off] */
+ || (insn & 0xf800) == 0x8000) /* strh Rd, [Rn, #off] */
+ && pv_is_register (regs[bits (insn, 3, 5)], ARM_SP_REGNUM))
+ /* Ignore stores of argument registers to the stack. */
+ ;
+ else if ((insn & 0xf800) == 0xc800 /* ldmia Rn!, { registers } */
+ && pv_is_register (regs[bits (insn, 8, 10)], ARM_SP_REGNUM))
+ /* Ignore block loads from the stack, potentially copying
+ parameters from memory. */
+ ;
+ else if ((insn & 0xf800) == 0x9800 /* ldr Rd, [Rn, #immed] */
+ || ((insn & 0xf800) == 0x6800 /* ldr Rd, [sp, #immed] */
+ && pv_is_register (regs[bits (insn, 3, 5)], ARM_SP_REGNUM)))
+ /* Similarly ignore single loads from the stack. */
+ ;
+ else if ((insn & 0xffc0) == 0x0000 /* lsls Rd, Rm, #0 */
+ || (insn & 0xffc0) == 0x1c00) /* add Rd, Rn, #0 */
+ /* Skip register copies, i.e. saves to another register
+ instead of the stack. */
+ ;
+ else if ((insn & 0xf800) == 0x2000) /* movs Rd, #imm */
+ /* Recognize constant loads; even with small stacks these are necessary
+ on Thumb. */
+ regs[bits (insn, 8, 10)] = pv_constant (bits (insn, 0, 7));
+ else if ((insn & 0xf800) == 0x4800) /* ldr Rd, [pc, #imm] */
+ {
+ /* Constant pool loads, for the same reason. */
+ unsigned int constant;
+ CORE_ADDR loc;
+
+ loc = start + 4 + bits (insn, 0, 7) * 4;
+ constant = read_memory_unsigned_integer (loc, 4, byte_order);
+ regs[bits (insn, 8, 10)] = pv_constant (constant);
+ }
+ else if ((insn & 0xe000) == 0xe000 && cache == NULL)
+ {
+ /* Only recognize 32-bit instructions for prologue skipping. */
+ unsigned short inst2;
+
+ inst2 = read_memory_unsigned_integer (start + 2, 2,
+ byte_order_for_code);
+
+ if ((insn & 0xf800) == 0xf000 && (inst2 & 0xe800) == 0xe800)
+ {
+ /* BL, BLX. Allow some special function calls when
+ skipping the prologue; GCC generates these before
+ storing arguments to the stack. */
+ CORE_ADDR nextpc;
+ int j1, j2, imm1, imm2;
+
+ imm1 = sbits (insn, 0, 10);
+ imm2 = bits (inst2, 0, 10);
+ j1 = bit (inst2, 13);
+ j2 = bit (inst2, 11);
+
+ offset = ((imm1 << 12) + (imm2 << 1));
+ offset ^= ((!j2) << 22) | ((!j1) << 23);
+
+ nextpc = start + 4 + offset;
+ /* For BLX make sure to clear the low bits. */
+ if (bit (inst2, 12) == 0)
+ nextpc = nextpc & 0xfffffffc;
+
+ if (!skip_prologue_function (nextpc))
+ break;
+ }
+ else if ((insn & 0xfe50) == 0xe800 /* stm{db,ia} Rn[!], { registers } */
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ else if ((insn & 0xfe50) == 0xe840 /* strd Rt, Rt2, [Rn, #imm] */
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ else if ((insn & 0xffd0) == 0xe890 /* ldmia Rn[!], { registers } */
+ && (inst2 & 0x8000) == 0x0000
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ else if ((insn & 0xfbf0) == 0xf100 /* add.w Rd, Rn, #imm */
+ && (inst2 & 0x8000) == 0x0000)
+ /* Since we only recognize this for prologue skipping, do not bother
+ to compute the constant. */
+ regs[bits (inst2, 8, 11)] = regs[bits (insn, 0, 3)];
+ else if ((insn & 0xfbf0) == 0xf1a0 /* sub.w Rd, Rn, #imm12 */
+ && (inst2 & 0x8000) == 0x0000)
+ /* Since we only recognize this for prologue skipping, do not bother
+ to compute the constant. */
+ regs[bits (inst2, 8, 11)] = regs[bits (insn, 0, 3)];
+ else if ((insn & 0xfbf0) == 0xf2a0 /* sub.w Rd, Rn, #imm8 */
+ && (inst2 & 0x8000) == 0x0000)
+ /* Since we only recognize this for prologue skipping, do not bother
+ to compute the constant. */
+ regs[bits (inst2, 8, 11)] = regs[bits (insn, 0, 3)];
+ else if ((insn & 0xff50) == 0xf850 /* ldr.w Rd, [Rn, #imm]{!} */
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ else if ((insn & 0xff50) == 0xe950 /* ldrd Rt, Rt2, [Rn, #imm]{!} */
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ else if ((insn & 0xff50) == 0xf800 /* strb.w or strh.w */
+ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM))
+ ;
+ 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;
+ }
else
{
/* We don't know what this instruction is. We're finished
@@ -366,15 +714,16 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
start += 2;
}
+ if (arm_debug)
+ fprintf_unfiltered (gdb_stdlog, "Prologue scan stopped at %s\n",
+ paddress (gdbarch, start));
+
if (cache == NULL)
{
do_cleanups (back_to);
return start;
}
- /* frameoffset is unused for this unwinder. */
- cache->frameoffset = 0;
-
if (pv_is_register (regs[ARM_FP_REGNUM], ARM_SP_REGNUM))
{
/* Frame pointer is fp. Frame size is constant. */
@@ -424,49 +773,81 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
sub fp, ip, #nn @@ nn == 20 or 4 depending on second insn */
static CORE_ADDR
-arm_skip_prologue (CORE_ADDR pc)
+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, func_end = 0;
- char *func_name;
+ 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 (pc))
- return pc;
-
- /* See what the symbol table says. */
-
- if (find_pc_partial_function (pc, &func_name, &func_addr, &func_end))
+ /* 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))
{
- struct symbol *sym;
+ CORE_ADDR post_prologue_pc
+ = skip_prologue_using_sal (gdbarch, func_addr);
+ struct symtab *s = find_pc_symtab (func_addr);
+
+ /* GCC always emits a line note before the prologue and another
+ one after, even if the two are at the same address or on the
+ same line. Take advantage of this so that we do not need to
+ know every instruction that might appear in the prologue. We
+ will have producer information for most binaries; if it is
+ missing (e.g. for -gstabs), assuming the GNU tools. */
+ if (post_prologue_pc
+ && (s == NULL
+ || s->producer == NULL
+ || strncmp (s->producer, "GNU ", sizeof ("GNU ") - 1) == 0))
+ return post_prologue_pc;
+
+ if (post_prologue_pc != 0)
+ {
+ CORE_ADDR analyzed_limit;
+
+ /* For non-GCC compilers, make sure the entire line is an
+ acceptable prologue; GDB will round this function's
+ return value up to the end of the following line so we
+ can not skip just part of a line (and we do not want to).
+
+ RealView does not treat the prologue specially, but does
+ associate prologue code with the opening brace; so this
+ lets us skip the first line if we think it is the opening
+ brace. */
+ if (arm_pc_is_thumb (func_addr))
+ analyzed_limit = thumb_analyze_prologue (gdbarch, func_addr,
+ post_prologue_pc, NULL);
+ else
+ analyzed_limit = arm_analyze_prologue (gdbarch, func_addr,
+ post_prologue_pc, NULL);
- /* Found a function. */
- sym = lookup_symbol (func_name, NULL, VAR_DOMAIN, NULL, NULL);
- if (sym && SYMBOL_LANGUAGE (sym) != language_asm)
- {
- /* Don't use this trick for assembly source files. */
- sal = find_pc_line (func_addr, 0);
- if ((sal.line != 0) && (sal.end < func_end))
- return sal.end;
- }
+ if (analyzed_limit != post_prologue_pc)
+ return func_addr;
+
+ return post_prologue_pc;
+ }
}
- /* Can't find the prologue end in the symbol table, try it the hard way
- by disassembling the instructions. */
+ /* 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. */
- if (func_end == 0 || func_end > pc + 64)
- func_end = 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 (current_gdbarch, pc, func_end, NULL);
+ return thumb_analyze_prologue (gdbarch, pc, limit_pc, NULL);
- for (skip_pc = pc; skip_pc < func_end; skip_pc += 4)
+ for (skip_pc = pc; skip_pc < limit_pc; skip_pc += 4)
{
- inst = read_memory_unsigned_integer (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 */
@@ -507,14 +888,14 @@ arm_skip_prologue (CORE_ADDR pc)
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] */
+ 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] */
+ 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. */
@@ -547,22 +928,15 @@ arm_skip_prologue (CORE_ADDR pc)
/* *INDENT-ON* */
static void
-thumb_scan_prologue (CORE_ADDR prev_pc, struct arm_prologue_cache *cache)
+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;
- /* Which register has been copied to register n? */
- int saved_reg[16];
- /* findmask:
- bit 0 - push { rlist }
- bit 1 - mov r7, sp OR add r7, sp, #imm (setting of r7)
- bit 2 - sub sp, #simm OR add sp, #simm (adjusting of sp)
- */
- int findmask = 0;
- int i;
- if (find_pc_partial_function (prev_pc, NULL, &prologue_start, &prologue_end))
+ if (find_pc_partial_function (block_addr, NULL, &prologue_start,
+ &prologue_end))
{
struct symtab_and_line sal = find_pc_line (prologue_start, 0);
@@ -578,162 +952,127 @@ thumb_scan_prologue (CORE_ADDR prev_pc, struct arm_prologue_cache *cache)
prologue_end = min (prologue_end, prev_pc);
- thumb_analyze_prologue (current_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 *next_frame, struct arm_prologue_cache *cache)
-{
- int regno, sp_offset, fp_offset, ip_offset;
- CORE_ADDR prologue_start, prologue_end, current_pc;
- CORE_ADDR prev_pc = frame_pc_unwind (next_frame);
-
- /* Assume there is no frame until proven otherwise. */
- cache->framereg = ARM_SP_REGNUM;
- cache->framesize = 0;
- cache->frameoffset = 0;
+ thumb_analyze_prologue (gdbarch, prologue_start, prologue_end, cache);
+}
- /* Check for Thumb prologue. */
- if (arm_pc_is_thumb (prev_pc))
- {
- thumb_scan_prologue (prev_pc, cache);
- return;
- }
+/* Return 1 if THIS_INSTR might change control flow, 0 otherwise. */
- /* 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 (prev_pc, 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:
+static 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;
- struct symtab_and_line sal = find_pc_line (prologue_start, 0);
+ /* Otherwise, miscellaneous instructions. */
- if (sal.line == 0)
- prologue_end = prev_pc;
- else if (sal.end < prologue_end)
- prologue_end = sal.end;
+ /* BX , BXJ , BLX */
+ if (bits (this_instr, 4, 27) == 0x12fff1
+ || bits (this_instr, 4, 27) == 0x12fff2
+ || bits (this_instr, 4, 27) == 0x12fff3)
+ return 1;
- 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.
+ /* 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");
+ }
+}
- 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;
+/* Analyze an ARM mode prologue starting at PROLOGUE_START and
+ continuing no further than PROLOGUE_END. If CACHE is non-NULL,
+ fill it in. Return the first address not recognized as a prologue
+ instruction.
- frame_loc = frame_unwind_register_unsigned (next_frame, ARM_FP_REGNUM);
- if (!safe_read_memory_integer (frame_loc, 4, &return_value))
- return;
- else
- {
- prologue_start = gdbarch_addr_bits_remove
- (current_gdbarch, return_value) - 8;
- prologue_end = prologue_start + 64; /* See above. */
- }
- }
+ We recognize all the instructions typically found in ARM prologues,
+ plus harmless instructions which can be skipped (either for analysis
+ purposes, or a more restrictive set that can be skipped when finding
+ the end of the prologue). */
- if (prev_pc < prologue_end)
- prologue_end = prev_pc;
+static CORE_ADDR
+arm_analyze_prologue (struct gdbarch *gdbarch,
+ CORE_ADDR prologue_start, CORE_ADDR prologue_end,
+ struct arm_prologue_cache *cache)
+{
+ 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 offset, current_pc;
+ pv_t regs[ARM_FPS_REGNUM];
+ struct pv_area *stack;
+ struct cleanup *back_to;
+ int framereg, framesize;
+ CORE_ADDR unrecognized_pc = 0;
- /* Now search the prologue looking for instructions that set up the
+ /* 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,
@@ -741,52 +1080,52 @@ arm_scan_prologue (struct frame_info *next_frame, struct arm_prologue_cache *cac
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] */
+ traceback. */
- sp_offset = fp_offset = ip_offset = 0;
+ 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);
+ unsigned int insn
+ = read_memory_unsigned_integer (current_pc, 4, byte_order_for_code);
if (insn == 0xe1a0c00d) /* mov ip, sp */
{
- ip_offset = 0;
+ regs[ARM_IP_REGNUM] = regs[ARM_SP_REGNUM];
continue;
}
- else if ((insn & 0xfffff000) == 0xe28dc000) /* add ip, sp #n */
+ else if ((insn & 0xfff00000) == 0xe2800000 /* add Rd, Rn, #n */
+ && pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM))
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
+ int rd = bits (insn, 12, 15);
imm = (imm >> rot) | (imm << (32 - rot));
- ip_offset = imm;
+ regs[rd] = pv_add_constant (regs[bits (insn, 16, 19)], imm);
continue;
}
- else if ((insn & 0xfffff000) == 0xe24dc000) /* sub ip, sp #n */
+ else if ((insn & 0xfff00000) == 0xe2400000 /* sub Rd, Rn, #n */
+ && pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM))
{
unsigned imm = insn & 0xff; /* immediate value */
unsigned rot = (insn & 0xf00) >> 7; /* rotate amount */
+ int rd = bits (insn, 12, 15);
imm = (imm >> rot) | (imm << (32 - rot));
- ip_offset = -imm;
+ regs[rd] = pv_add_constant (regs[bits (insn, 16, 19)], -imm);
continue;
}
- else if (insn == 0xe52de004) /* str lr, [sp, #-4]! */
+ else if ((insn & 0xffff0fff) == 0xe52d0004) /* str Rd, [sp, #-4]! */
{
- sp_offset -= 4;
- cache->saved_regs[ARM_LR_REGNUM].addr = sp_offset;
+ 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[bits (insn, 12, 15)]);
continue;
}
else if ((insn & 0xffff0000) == 0xe92d0000)
@@ -796,56 +1135,70 @@ arm_scan_prologue (struct frame_info *next_frame, struct arm_prologue_cache *cac
{
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))
{
- sp_offset -= 4;
- cache->saved_regs[regno].addr = sp_offset;
+ 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] */
+ else if ((insn & 0xffff0000) == 0xe54b0000 /* strb rx,[r11,#-n] */
+ || (insn & 0xffff00f0) == 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] */
+ else if ((insn & 0xffff0000) == 0xe5cd0000 /* strb rx,[sp,#n] */
+ || (insn & 0xffff00f0) == 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 & 0xfff00000) == 0xe8800000 /* stm Rn, { registers } */
+ && pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM))
+ {
+ /* No need to add this to saved_regs -- it's just arg regs. */
+ 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));
- fp_offset = -imm + ip_offset;
- cache->framereg = ARM_FP_REGNUM;
+ 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));
- sp_offset -= imm;
+ regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -imm);
}
else if ((insn & 0xffff7fff) == 0xed6d0103 /* stfe f?, [sp, -#c]! */
- && gdbarch_tdep (current_gdbarch)->have_fpa_registers)
+ && gdbarch_tdep (gdbarch)->have_fpa_registers)
{
- sp_offset -= 12;
+ 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);
- cache->saved_regs[regno].addr = sp_offset;
+ pv_area_store (stack, regs[ARM_SP_REGNUM], 12, regs[regno]);
}
else if ((insn & 0xffbf0fff) == 0xec2d0200 /* sfmfd f0, 4, [sp!] */
- && gdbarch_tdep (current_gdbarch)->have_fpa_registers)
+ && 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 */
@@ -865,51 +1218,216 @@ arm_scan_prologue (struct frame_info *next_frame, struct arm_prologue_cache *cac
fp_bound_reg = fp_start_reg + n_saved_fp_regs;
for (; fp_start_reg < fp_bound_reg; fp_start_reg++)
{
- sp_offset -= 12;
- cache->saved_regs[fp_start_reg++].addr = sp_offset;
+ 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 & 0xff000000) == 0xeb000000 && cache == NULL) /* bl */
+ {
+ /* Allow some special function calls when skipping the
+ prologue; GCC generates these before storing arguments to
+ the stack. */
+ CORE_ADDR dest = BranchDest (current_pc, insn);
+
+ if (skip_prologue_function (dest))
+ continue;
+ else
+ break;
+ }
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. */
+ else if (arm_instruction_changes_pc (insn))
+ /* Don't scan past anything that might change control flow. */
+ break;
+ else if ((insn & 0xfe500000) == 0xe8100000) /* ldm */
+ {
+ /* Ignore block loads from the stack, potentially copying
+ parameters from memory. */
+ if (pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM))
+ continue;
+ else
+ break;
+ }
+ else if ((insn & 0xfc500000) == 0xe4100000)
+ {
+ /* Similarly ignore single loads from the stack. */
+ if (pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM))
+ continue;
+ else
+ break;
+ }
+ else if ((insn & 0xffff0ff0) == 0xe1a00000)
+ /* MOV Rd, Rm. Skip register copies, i.e. saves to another
+ register instead of the stack. */
continue;
+ else
+ {
+ /* The optimizer might shove anything into the prologue,
+ so we just skip what we don't recognize. */
+ unrecognized_pc = current_pc;
+ continue;
+ }
}
- /* The frame size is just the negative of the offset (from the
- original SP) of the last thing thing we pushed on the stack.
- The frame offset is [new FP] - [new SP]. */
- cache->framesize = -sp_offset;
- if (cache->framereg == ARM_FP_REGNUM)
- cache->frameoffset = fp_offset - sp_offset;
+ if (unrecognized_pc == 0)
+ unrecognized_pc = current_pc;
+
+ /* 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. */
+ framereg = ARM_FP_REGNUM;
+ 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. */
+ framereg = ARM_SP_REGNUM;
+ framesize = -regs[ARM_SP_REGNUM].k;
+ }
else
- cache->frameoffset = 0;
-}
+ {
+ /* We're just out of luck. We don't know where the frame is. */
+ framereg = -1;
+ framesize = 0;
+ }
-static struct arm_prologue_cache *
-arm_make_prologue_cache (struct frame_info *next_frame)
+ if (cache)
+ {
+ cache->framereg = framereg;
+ cache->framesize = framesize;
+
+ for (regno = 0; regno < ARM_FPS_REGNUM; regno++)
+ if (pv_area_find_reg (stack, gdbarch, regno, &offset))
+ cache->saved_regs[regno].addr = offset;
+ }
+
+ if (arm_debug)
+ fprintf_unfiltered (gdb_stdlog, "Prologue scan stopped at %s\n",
+ paddress (gdbarch, unrecognized_pc));
+
+ do_cleanups (back_to);
+ return unrecognized_pc;
+}
+
+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);
+ 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;
+
+ arm_analyze_prologue (gdbarch, prologue_start, prologue_end, cache);
+}
+
+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 (next_frame);
+ cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
- arm_scan_prologue (next_frame, cache);
+ arm_scan_prologue (this_frame, cache);
- unwound_fp = frame_unwind_register_unsigned (next_frame, cache->framereg);
+ unwound_fp = get_frame_register_unsigned (this_frame, cache->framereg);
if (unwound_fp == 0)
return cache;
- cache->prev_sp = unwound_fp + cache->framesize - cache->frameoffset;
+ 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 (current_gdbarch); reg++)
+ 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;
@@ -920,93 +1438,106 @@ arm_make_prologue_cache (struct frame_info *next_frame)
and the caller's SP when we were called. */
static void
-arm_prologue_this_id (struct frame_info *next_frame,
+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 func;
+ CORE_ADDR pc, func;
if (*this_cache == NULL)
- *this_cache = arm_make_prologue_cache (next_frame);
+ *this_cache = arm_make_prologue_cache (this_frame);
cache = *this_cache;
- func = frame_func_unwind (next_frame, NORMAL_FRAME);
-
- /* This is meant to halt the backtrace at "_start". Make sure we
- don't halt it at a generic dummy frame. */
- if (func <= LOWEST_PC)
+ /* 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 void
-arm_prologue_prev_register (struct frame_info *next_frame,
+static struct value *
+arm_prologue_prev_register (struct frame_info *this_frame,
void **this_cache,
- int prev_regnum,
- int *optimized,
- enum lval_type *lvalp,
- CORE_ADDR *addrp,
- int *realnump,
- gdb_byte *valuep)
+ 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 (next_frame);
+ *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 saved value of PC points into this frame's
- prologue, not the next frame's resume location. */
+ 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)
- prev_regnum = ARM_LR_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 NEXT_FRAME's stack pointer at the time of the call.
+ 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)
{
- *lvalp = not_lval;
- if (valuep)
- store_unsigned_integer (valuep, 4, cache->prev_sp);
- return;
+ 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);
}
- trad_frame_get_prev_register (next_frame, cache->saved_regs, prev_regnum,
- optimized, lvalp, addrp, realnump, valuep);
+ 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
+ arm_prologue_prev_register,
+ NULL,
+ default_frame_sniffer
};
-static const struct frame_unwind *
-arm_prologue_unwind_sniffer (struct frame_info *next_frame)
-{
- return &arm_prologue_unwind;
-}
-
static struct arm_prologue_cache *
-arm_make_stub_cache (struct frame_info *next_frame)
+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 (next_frame);
+ cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
- cache->prev_sp = frame_unwind_register_unsigned (next_frame, ARM_SP_REGNUM);
+ cache->prev_sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
return cache;
}
@@ -1014,50 +1545,55 @@ arm_make_stub_cache (struct frame_info *next_frame)
/* Our frame ID for a stub frame is the current SP and LR. */
static void
-arm_stub_this_id (struct frame_info *next_frame,
+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 (next_frame);
+ *this_cache = arm_make_stub_cache (this_frame);
cache = *this_cache;
- *this_id = frame_id_build (cache->prev_sp,
- frame_pc_unwind (next_frame));
+ *this_id = frame_id_build (cache->prev_sp, get_frame_pc (this_frame));
}
-struct frame_unwind arm_stub_unwind = {
- NORMAL_FRAME,
- arm_stub_this_id,
- arm_prologue_prev_register
-};
-
-static const struct frame_unwind *
-arm_stub_unwind_sniffer (struct frame_info *next_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 = frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
+ addr_in_block = get_frame_address_in_block (this_frame);
if (in_plt_section (addr_in_block, NULL)
- || target_read_memory (frame_pc_unwind (next_frame), dummy, 4) != 0)
- return &arm_stub_unwind;
+ /* We also use the stub winder if the target memory is unreadable
+ to avoid having the prologue unwinder trying to read it. */
+ || target_read_memory (get_frame_pc (this_frame), dummy, 4) != 0)
+ return 1;
- return NULL;
+ 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 *next_frame, void **this_cache)
+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 (next_frame);
+ *this_cache = arm_make_prologue_cache (this_frame);
cache = *this_cache;
- return cache->prev_sp + cache->frameoffset - cache->framesize;
+ return cache->prev_sp - cache->framesize;
}
struct frame_base arm_normal_base = {
@@ -1067,17 +1603,17 @@ struct frame_base arm_normal_base = {
arm_normal_frame_base
};
-/* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
+/* 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_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
+arm_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
{
- return frame_id_build (frame_unwind_register_unsigned (next_frame, ARM_SP_REGNUM),
- frame_pc_unwind (next_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
@@ -1089,7 +1625,7 @@ 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 (pc);
+ return arm_addr_bits_remove (gdbarch, pc);
}
static CORE_ADDR
@@ -1098,6 +1634,58 @@ 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. */
@@ -1109,7 +1697,7 @@ struct stack_item
};
static struct stack_item *
-push_stack_item (struct stack_item *prev, void *contents, int len)
+push_stack_item (struct stack_item *prev, const void *contents, int len)
{
struct stack_item *si;
si = xmalloc (sizeof (struct stack_item));
@@ -1178,8 +1766,222 @@ arm_type_align (struct type *t)
}
}
-/* We currently only support passing parameters in integer registers. This
- conforms with GCC's default model. Several other variants exist and
+/* 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
@@ -1188,14 +1990,26 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
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. */
+ if (arm_pc_is_thumb (bp_addr))
+ bp_addr |= 1;
regcache_cooked_write_unsigned (regcache, ARM_LR_REGNUM, bp_addr);
/* Walk through the list of args and determine how large a temporary
@@ -1211,9 +2025,9 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
if (struct_return)
{
if (arm_debug)
- fprintf_unfiltered (gdb_stdlog, "struct return in %s = 0x%s\n",
- gdbarch_register_name (current_gdbarch, argreg),
- paddr (struct_addr));
+ 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++;
}
@@ -1224,14 +2038,17 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
struct type *arg_type;
struct type *target_type;
enum type_code typecode;
- bfd_byte *val;
+ const 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]);
+ val = value_contents (args[argnum]);
align = arm_type_align (arg_type);
/* Round alignment up to a whole number of words. */
@@ -1249,6 +2066,65 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
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))
{
@@ -1257,7 +2133,8 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
}
/* Doubleword aligned quantities must go in even register pairs. */
- if (argreg <= ARM_LAST_ARG_REGNUM
+ if (may_use_core_reg
+ && argreg <= ARM_LAST_ARG_REGNUM
&& align > INT_REGISTER_SIZE
&& argreg & 1)
argreg++;
@@ -1267,13 +2144,15 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
the THUMB bit in it. */
if (TYPE_CODE_PTR == typecode
&& target_type != NULL
- && TYPE_CODE_FUNC == TYPE_CODE (target_type))
+ && TYPE_CODE_FUNC == TYPE_CODE (check_typedef (target_type)))
{
- CORE_ADDR regval = extract_unsigned_integer (val, len);
+ CORE_ADDR regval = extract_unsigned_integer (val, len, byte_order);
if (arm_pc_is_thumb (regval))
{
- val = alloca (len);
- store_unsigned_integer (val, len, MAKE_THUMB_ADDR (regval));
+ bfd_byte *copy = alloca (len);
+ store_unsigned_integer (copy, len, byte_order,
+ MAKE_THUMB_ADDR (regval));
+ val = copy;
}
}
@@ -1282,19 +2161,22 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
registers and stack. */
while (len > 0)
{
- int partial_len = len < DEPRECATED_REGISTER_SIZE ? len : DEPRECATED_REGISTER_SIZE;
+ int partial_len = len < INT_REGISTER_SIZE ? len : INT_REGISTER_SIZE;
- if (argreg <= ARM_LAST_ARG_REGNUM)
+ 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);
+ 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
- (current_gdbarch, argreg),
- phex (regval, DEPRECATED_REGISTER_SIZE));
+ (gdbarch, argreg),
+ phex (regval, INT_REGISTER_SIZE));
regcache_cooked_write_unsigned (regcache, argreg, regval);
argreg++;
}
@@ -1304,8 +2186,8 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
if (arm_debug)
fprintf_unfiltered (gdb_stdlog, "arg %d @ sp + %d\n",
argnum, nstack);
- si = push_stack_item (si, val, DEPRECATED_REGISTER_SIZE);
- nstack += DEPRECATED_REGISTER_SIZE;
+ si = push_stack_item (si, val, INT_REGISTER_SIZE);
+ nstack += INT_REGISTER_SIZE;
}
len -= partial_len;
@@ -1379,38 +2261,153 @@ arm_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
print_fpu_flags (status);
}
-/* Return the GDB type object for the "standard" data type of data in
- register N. */
+/* 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_register_type (struct gdbarch *gdbarch, int regnum)
+arm_neon_double_type (struct gdbarch *gdbarch)
{
- if (regnum >= ARM_F0_REGNUM && regnum < ARM_F0_REGNUM + NUM_FREGS)
- return builtin_type_arm_ext;
- else if (regnum == ARM_SP_REGNUM)
- return builtin_type_void_data_ptr;
- else if (regnum == ARM_PC_REGNUM)
- return builtin_type_void_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_int0;
- else
- return builtin_type_uint32;
+ 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;
}
-/* Map a DWARF register REGNUM onto the appropriate GDB register
- number. */
+/* 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 int
-arm_dwarf_reg_to_regnum (int reg)
+static struct type *
+arm_neon_quad_type (struct gdbarch *gdbarch)
{
- /* Core integer regs. */
- if (reg >= 0 && reg <= 15)
- return reg;
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
- /* Legacy FPA encoding. These were once used in a way which
- overlapped with VFP register numbering, so their use is
+ 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)
@@ -1430,15 +2427,43 @@ arm_dwarf_reg_to_regnum (int reg)
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 (int regnum)
+arm_register_sim_regno (struct gdbarch *gdbarch, int regnum)
{
int reg = regnum;
- gdb_assert (reg >= 0 && reg < gdbarch_num_regs (current_gdbarch));
+ 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;
@@ -1471,10 +2496,11 @@ arm_register_sim_regno (int regnum)
static void
convert_from_extended (const struct floatformat *fmt, const void *ptr,
- void *dbl)
+ void *dbl, int endianess)
{
DOUBLEST d;
- if (gdbarch_byte_order (current_gdbarch) == BFD_ENDIAN_BIG)
+
+ if (endianess == BFD_ENDIAN_BIG)
floatformat_to_doublest (&floatformat_arm_ext_big, ptr, &d);
else
floatformat_to_doublest (&floatformat_arm_ext_littlebyte_bigword,
@@ -1483,11 +2509,13 @@ convert_from_extended (const struct floatformat *fmt, const void *ptr,
}
static void
-convert_to_extended (const struct floatformat *fmt, void *dbl, const void *ptr)
+convert_to_extended (const struct floatformat *fmt, void *dbl, const void *ptr,
+ int endianess)
{
DOUBLEST d;
+
floatformat_to_doublest (fmt, ptr, &d);
- if (gdbarch_byte_order (current_gdbarch) == BFD_ENDIAN_BIG)
+ if (endianess == BFD_ENDIAN_BIG)
floatformat_from_doublest (&floatformat_arm_ext_big, &d, dbl);
else
floatformat_from_doublest (&floatformat_arm_ext_littlebyte_bigword,
@@ -1527,25 +2555,17 @@ condition_true (unsigned long cond, unsigned long status_reg)
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)));
+ 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 (((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)
@@ -1564,8 +2584,7 @@ shifted_reg_val (struct frame_info *frame, unsigned long inst, int carry,
shift = bits (inst, 7, 11);
res = (rm == 15
- ? ((pc_val | (ARM_PC_32 ? 0 : status_reg))
- + (bit (inst, 4) ? 12 : 8))
+ ? (pc_val + (bit (inst, 4) ? 12 : 8))
: get_frame_register_unsigned (frame, rm));
switch (shifttype)
@@ -1608,13 +2627,173 @@ bitcount (unsigned long val)
return nbits;
}
+/* Return the size in bytes of the complete Thumb instruction whose
+ first halfword is INST1. */
+
+static int
+thumb_insn_size (unsigned short inst1)
+{
+ if ((inst1 & 0xe000) == 0xe000 && (inst1 & 0x1800) != 0)
+ return 4;
+ else
+ return 2;
+}
+
+static 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;
+}
+
+/* Find the next PC after the current instruction executes. In some
+ cases we can not statically determine the answer (see the IT state
+ handling in this function); in that case, a breakpoint may be
+ inserted in addition to the returned PC, which will be used to set
+ another breakpoint by our caller. */
+
static CORE_ADDR
-thumb_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
+thumb_get_next_pc_raw (struct frame_info *frame, CORE_ADDR pc, int insert_bkpt)
{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct address_space *aspace = get_frame_address_space (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 = read_memory_unsigned_integer (pc, 2);
+ unsigned short inst1;
CORE_ADDR nextpc = pc + 2; /* default is next instruction */
unsigned long offset;
+ ULONGEST status, itstate;
+
+ nextpc = MAKE_THUMB_ADDR (nextpc);
+ pc_val = MAKE_THUMB_ADDR (pc_val);
+
+ inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
+
+ /* Thumb-2 conditional execution support. There are eight bits in
+ the CPSR which describe conditional execution state. Once
+ reconstructed (they're in a funny order), the low five bits
+ describe the low bit of the condition for each instruction and
+ how many instructions remain. The high three bits describe the
+ base condition. One of the low four bits will be set if an IT
+ block is active. These bits read as zero on earlier
+ processors. */
+ status = get_frame_register_unsigned (frame, ARM_PS_REGNUM);
+ itstate = ((status >> 8) & 0xfc) | ((status >> 25) & 0x3);
+
+ /* If-Then handling. On GNU/Linux, where this routine is used, we
+ use an undefined instruction as a breakpoint. Unlike BKPT, IT
+ can disable execution of the undefined instruction. So we might
+ miss the breakpoint if we set it on a skipped conditional
+ instruction. Because conditional instructions can change the
+ flags, affecting the execution of further instructions, we may
+ need to set two breakpoints. */
+
+ if (gdbarch_tdep (gdbarch)->thumb2_breakpoint != NULL)
+ {
+ if ((inst1 & 0xff00) == 0xbf00 && (inst1 & 0x000f) != 0)
+ {
+ /* An IT instruction. Because this instruction does not
+ modify the flags, we can accurately predict the next
+ executed instruction. */
+ itstate = inst1 & 0x00ff;
+ pc += thumb_insn_size (inst1);
+
+ while (itstate != 0 && ! condition_true (itstate >> 4, status))
+ {
+ inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
+ pc += thumb_insn_size (inst1);
+ itstate = thumb_advance_itstate (itstate);
+ }
+
+ return MAKE_THUMB_ADDR (pc);
+ }
+ else if (itstate != 0)
+ {
+ /* We are in a conditional block. Check the condition. */
+ if (! condition_true (itstate >> 4, status))
+ {
+ /* Advance to the next executed instruction. */
+ pc += thumb_insn_size (inst1);
+ itstate = thumb_advance_itstate (itstate);
+
+ while (itstate != 0 && ! condition_true (itstate >> 4, status))
+ {
+ inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
+ pc += thumb_insn_size (inst1);
+ itstate = thumb_advance_itstate (itstate);
+ }
+
+ return MAKE_THUMB_ADDR (pc);
+ }
+ else if ((itstate & 0x0f) == 0x08)
+ {
+ /* This is the last instruction of the conditional
+ block, and it is executed. We can handle it normally
+ because the following instruction is not conditional,
+ and we must handle it normally because it is
+ permitted to branch. Fall through. */
+ }
+ else
+ {
+ int cond_negated;
+
+ /* There are conditional instructions after this one.
+ If this instruction modifies the flags, then we can
+ not predict what the next executed instruction will
+ be. Fortunately, this instruction is architecturally
+ forbidden to branch; we know it will fall through.
+ Start by skipping past it. */
+ pc += thumb_insn_size (inst1);
+ itstate = thumb_advance_itstate (itstate);
+
+ /* Set a breakpoint on the following instruction. */
+ gdb_assert ((itstate & 0x0f) != 0);
+ if (insert_bkpt)
+ insert_single_step_breakpoint (gdbarch, aspace, pc);
+ cond_negated = (itstate >> 4) & 1;
+
+ /* Skip all following instructions with the same
+ condition. If there is a later instruction in the IT
+ block with the opposite condition, set the other
+ breakpoint there. If not, then set a breakpoint on
+ the instruction after the IT block. */
+ do
+ {
+ inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
+ pc += thumb_insn_size (inst1);
+ itstate = thumb_advance_itstate (itstate);
+ }
+ while (itstate != 0 && ((itstate >> 4) & 1) == cond_negated);
+
+ return MAKE_THUMB_ADDR (pc);
+ }
+ }
+ }
+ else if (itstate & 0x0f)
+ {
+ /* We are in a conditional block. Check the condition. */
+ int cond = itstate >> 4;
+
+ if (! condition_true (cond, status))
+ {
+ /* Advance to the next instruction. All the 32-bit
+ instructions share a common prefix. */
+ if ((inst1 & 0xe000) == 0xe000 && (inst1 & 0x1800) != 0)
+ return MAKE_THUMB_ADDR (pc + 4);
+ else
+ return MAKE_THUMB_ADDR (pc + 2);
+ }
+
+ /* Otherwise, handle the instruction normally. */
+ }
if ((inst1 & 0xff00) == 0xbd00) /* pop {rlist, pc} */
{
@@ -1622,16 +2801,12 @@ thumb_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
/* Fetch the saved PC from the stack. It's stored above
all of the other registers. */
- offset = bitcount (bits (inst1, 0, 7)) * DEPRECATED_REGISTER_SIZE;
+ offset = bitcount (bits (inst1, 0, 7)) * INT_REGISTER_SIZE;
sp = get_frame_register_unsigned (frame, ARM_SP_REGNUM);
- nextpc = (CORE_ADDR) read_memory_unsigned_integer (sp + offset, 4);
- nextpc = gdbarch_addr_bits_remove (current_gdbarch, nextpc);
- if (nextpc == pc)
- error (_("Infinite loop detected"));
+ nextpc = read_memory_unsigned_integer (sp + offset, 4, byte_order);
}
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);
@@ -1640,14 +2815,178 @@ thumb_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
{
nextpc = pc_val + (sbits (inst1, 0, 10) << 1);
}
- else if ((inst1 & 0xf800) == 0xf000) /* long branch with link, and blx */
+ else if ((inst1 & 0xe000) == 0xe000) /* 32-bit instruction */
{
- unsigned short inst2 = read_memory_unsigned_integer (pc + 2, 2);
- 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;
+ unsigned short inst2;
+ inst2 = read_memory_unsigned_integer (pc + 2, 2, byte_order_for_code);
+
+ /* Default to the next instruction. */
+ nextpc = pc + 4;
+ nextpc = MAKE_THUMB_ADDR (nextpc);
+
+ if ((inst1 & 0xf800) == 0xf000 && (inst2 & 0x8000) == 0x8000)
+ {
+ /* Branches and miscellaneous control instructions. */
+
+ if ((inst2 & 0x1000) != 0 || (inst2 & 0xd001) == 0xc000)
+ {
+ /* B, BL, BLX. */
+ int j1, j2, imm1, imm2;
+
+ imm1 = sbits (inst1, 0, 10);
+ imm2 = bits (inst2, 0, 10);
+ j1 = bit (inst2, 13);
+ j2 = bit (inst2, 11);
+
+ offset = ((imm1 << 12) + (imm2 << 1));
+ offset ^= ((!j2) << 22) | ((!j1) << 23);
+
+ nextpc = pc_val + offset;
+ /* For BLX make sure to clear the low bits. */
+ if (bit (inst2, 12) == 0)
+ nextpc = nextpc & 0xfffffffc;
+ }
+ else if (inst1 == 0xf3de && (inst2 & 0xff00) == 0x3f00)
+ {
+ /* SUBS PC, LR, #imm8. */
+ nextpc = get_frame_register_unsigned (frame, ARM_LR_REGNUM);
+ nextpc -= inst2 & 0x00ff;
+ }
+ else if ((inst2 & 0xd000) == 0x8000 && (inst1 & 0x0380) != 0x0380)
+ {
+ /* Conditional branch. */
+ if (condition_true (bits (inst1, 6, 9), status))
+ {
+ int sign, j1, j2, imm1, imm2;
+
+ sign = sbits (inst1, 10, 10);
+ imm1 = bits (inst1, 0, 5);
+ imm2 = bits (inst2, 0, 10);
+ j1 = bit (inst2, 13);
+ j2 = bit (inst2, 11);
+
+ offset = (sign << 20) + (j2 << 19) + (j1 << 18);
+ offset += (imm1 << 12) + (imm2 << 1);
+
+ nextpc = pc_val + offset;
+ }
+ }
+ }
+ else if ((inst1 & 0xfe50) == 0xe810)
+ {
+ /* Load multiple or RFE. */
+ int rn, offset, load_pc = 1;
+
+ rn = bits (inst1, 0, 3);
+ if (bit (inst1, 7) && !bit (inst1, 8))
+ {
+ /* LDMIA or POP */
+ if (!bit (inst2, 15))
+ load_pc = 0;
+ offset = bitcount (inst2) * 4 - 4;
+ }
+ else if (!bit (inst1, 7) && bit (inst1, 8))
+ {
+ /* LDMDB */
+ if (!bit (inst2, 15))
+ load_pc = 0;
+ offset = -4;
+ }
+ else if (bit (inst1, 7) && bit (inst1, 8))
+ {
+ /* RFEIA */
+ offset = 0;
+ }
+ else if (!bit (inst1, 7) && !bit (inst1, 8))
+ {
+ /* RFEDB */
+ offset = -8;
+ }
+ else
+ load_pc = 0;
+
+ if (load_pc)
+ {
+ CORE_ADDR addr = get_frame_register_unsigned (frame, rn);
+ nextpc = get_frame_memory_unsigned (frame, addr + offset, 4);
+ }
+ }
+ else if ((inst1 & 0xffef) == 0xea4f && (inst2 & 0xfff0) == 0x0f00)
+ {
+ /* MOV PC or MOVS PC. */
+ nextpc = get_frame_register_unsigned (frame, bits (inst2, 0, 3));
+ nextpc = MAKE_THUMB_ADDR (nextpc);
+ }
+ else if ((inst1 & 0xff70) == 0xf850 && (inst2 & 0xf000) == 0xf000)
+ {
+ /* LDR PC. */
+ CORE_ADDR base;
+ int rn, load_pc = 1;
+
+ rn = bits (inst1, 0, 3);
+ base = get_frame_register_unsigned (frame, rn);
+ if (rn == 15)
+ {
+ base = (base + 4) & ~(CORE_ADDR) 0x3;
+ if (bit (inst1, 7))
+ base += bits (inst2, 0, 11);
+ else
+ base -= bits (inst2, 0, 11);
+ }
+ else if (bit (inst1, 7))
+ base += bits (inst2, 0, 11);
+ else if (bit (inst2, 11))
+ {
+ if (bit (inst2, 10))
+ {
+ if (bit (inst2, 9))
+ base += bits (inst2, 0, 7);
+ else
+ base -= bits (inst2, 0, 7);
+ }
+ }
+ else if ((inst2 & 0x0fc0) == 0x0000)
+ {
+ int shift = bits (inst2, 4, 5), rm = bits (inst2, 0, 3);
+ base += get_frame_register_unsigned (frame, rm) << shift;
+ }
+ else
+ /* Reserved. */
+ load_pc = 0;
+
+ if (load_pc)
+ nextpc = get_frame_memory_unsigned (frame, base, 4);
+ }
+ else if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf000)
+ {
+ /* TBB. */
+ CORE_ADDR tbl_reg, table, offset, length;
+
+ tbl_reg = bits (inst1, 0, 3);
+ if (tbl_reg == 0x0f)
+ table = pc + 4; /* Regcache copy of PC isn't right yet. */
+ else
+ table = get_frame_register_unsigned (frame, tbl_reg);
+
+ offset = get_frame_register_unsigned (frame, bits (inst2, 0, 3));
+ length = 2 * get_frame_memory_unsigned (frame, table + offset, 1);
+ nextpc = pc_val + length;
+ }
+ else if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf010)
+ {
+ /* TBH. */
+ CORE_ADDR tbl_reg, table, offset, length;
+
+ tbl_reg = bits (inst1, 0, 3);
+ if (tbl_reg == 0x0f)
+ table = pc + 4; /* Regcache copy of PC isn't right yet. */
+ else
+ table = get_frame_register_unsigned (frame, tbl_reg);
+
+ offset = 2 * get_frame_register_unsigned (frame, bits (inst2, 0, 3));
+ length = 2 * get_frame_memory_unsigned (frame, table + offset, 2);
+ nextpc = pc_val + length;
+ }
}
else if ((inst1 & 0xff00) == 0x4700) /* bx REG, blx REG */
{
@@ -1655,32 +2994,71 @@ thumb_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
nextpc = pc_val;
else
nextpc = get_frame_register_unsigned (frame, bits (inst1, 3, 6));
-
- nextpc = gdbarch_addr_bits_remove (current_gdbarch, nextpc);
- if (nextpc == pc)
- error (_("Infinite loop detected"));
}
-
+ else if ((inst1 & 0xf500) == 0xb100)
+ {
+ /* CBNZ or CBZ. */
+ int imm = (bit (inst1, 9) << 6) + (bits (inst1, 3, 7) << 1);
+ ULONGEST reg = get_frame_register_unsigned (frame, bits (inst1, 0, 2));
+
+ if (bit (inst1, 11) && reg != 0)
+ nextpc = pc_val + imm;
+ else if (!bit (inst1, 11) && reg == 0)
+ nextpc = pc_val + imm;
+ }
return nextpc;
}
+/* Get the raw next address. PC is the current program counter, in
+ FRAME. INSERT_BKPT should be TRUE if we want a breakpoint set on
+ the alternative next instruction if there are two options.
+
+ The value returned has the execution state of the next instruction
+ encoded in it. Use IS_THUMB_ADDR () to see whether the instruction is
+ in Thumb-State, and gdbarch_addr_bits_remove () to get the plain memory
+ address.
+*/
static CORE_ADDR
-arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
+arm_get_next_pc_raw (struct frame_info *frame, CORE_ADDR pc, int insert_bkpt)
{
+ 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_pc_is_thumb (pc))
- return thumb_get_next_pc (frame, pc);
+ if (arm_frame_is_thumb (frame))
+ return thumb_get_next_pc_raw (frame, pc, insert_bkpt);
pc_val = (unsigned long) pc;
- this_instr = read_memory_unsigned_integer (pc, 4);
+ 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 (condition_true (bits (this_instr, 28, 31), status))
+ 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 = MAKE_THUMB_ADDR (nextpc);
+ 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))
{
@@ -1705,14 +3083,8 @@ arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
|| bits (this_instr, 4, 27) == 0x12fff3)
{
rn = bits (this_instr, 0, 3);
- result = (rn == 15) ? pc_val + 8
+ nextpc = (rn == 15) ? pc_val + 8
: get_frame_register_unsigned (frame, rn);
- nextpc = (CORE_ADDR) gdbarch_addr_bits_remove
- (current_gdbarch, result);
-
- if (nextpc == pc)
- error (_("Infinite loop detected"));
-
return nextpc;
}
@@ -1790,11 +3162,14 @@ arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
result = ~operand2;
break;
}
- nextpc = (CORE_ADDR) gdbarch_addr_bits_remove
- (current_gdbarch, result);
- if (nextpc == pc)
- error (_("Infinite loop detected"));
+ /* In 26-bit APCS the bottom two bits of the result are
+ ignored, and we always end up in ARM state. */
+ if (!arm_apcs_32)
+ nextpc = arm_addr_bits_remove (gdbarch, result);
+ else
+ nextpc = result;
+
break;
}
@@ -1833,12 +3208,7 @@ arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
base -= offset;
}
nextpc = (CORE_ADDR) read_memory_integer ((CORE_ADDR) base,
- 4);
-
- nextpc = gdbarch_addr_bits_remove (current_gdbarch, nextpc);
-
- if (nextpc == pc)
- error (_("Infinite loop detected"));
+ 4, byte_order);
}
}
break;
@@ -1853,80 +3223,2120 @@ arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
/* 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;
+ 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);
+ }
+ }
+ }
+ break;
+
+ case 0xb: /* branch & link */
+ case 0xa: /* branch */
+ {
+ nextpc = BranchDest (pc, this_instr);
+ 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;
+}
+
+CORE_ADDR
+arm_get_next_pc (struct frame_info *frame, CORE_ADDR pc)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ CORE_ADDR nextpc =
+ gdbarch_addr_bits_remove (gdbarch,
+ arm_get_next_pc_raw (frame, pc, TRUE));
+ if (nextpc == pc)
+ error (_("Infinite loop detected"));
+ 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);
+ struct address_space *aspace = get_frame_address_space (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, aspace, next_pc);
+
+ return 1;
+}
+
+/* Given BUF, which is OLD_LEN bytes ending at ENDADDR, expand
+ the buffer to be NEW_LEN bytes ending at ENDADDR. Return
+ NULL if an error occurs. BUF is freed. */
+
+static gdb_byte *
+extend_buffer_earlier (gdb_byte *buf, CORE_ADDR endaddr,
+ int old_len, int new_len)
+{
+ gdb_byte *new_buf, *middle;
+ int bytes_to_read = new_len - old_len;
+
+ new_buf = xmalloc (new_len);
+ memcpy (new_buf + bytes_to_read, buf, old_len);
+ xfree (buf);
+ if (target_read_memory (endaddr - new_len, new_buf, bytes_to_read) != 0)
+ {
+ xfree (new_buf);
+ return NULL;
+ }
+ return new_buf;
+}
+
+/* An IT block is at most the 2-byte IT instruction followed by
+ four 4-byte instructions. The furthest back we must search to
+ find an IT block that affects the current instruction is thus
+ 2 + 3 * 4 == 14 bytes. */
+#define MAX_IT_BLOCK_PREFIX 14
+
+/* Use a quick scan if there are more than this many bytes of
+ code. */
+#define IT_SCAN_THRESHOLD 32
+
+/* Adjust a breakpoint's address to move breakpoints out of IT blocks.
+ A breakpoint in an IT block may not be hit, depending on the
+ condition flags. */
+static CORE_ADDR
+arm_adjust_breakpoint_address (struct gdbarch *gdbarch, CORE_ADDR bpaddr)
+{
+ gdb_byte *buf;
+ char map_type;
+ CORE_ADDR boundary, func_start;
+ int buf_len, buf2_len;
+ enum bfd_endian order = gdbarch_byte_order_for_code (gdbarch);
+ int i, any, last_it, last_it_count;
+
+ /* If we are using BKPT breakpoints, none of this is necessary. */
+ if (gdbarch_tdep (gdbarch)->thumb2_breakpoint == NULL)
+ return bpaddr;
+
+ /* ARM mode does not have this problem. */
+ if (!arm_pc_is_thumb (bpaddr))
+ return bpaddr;
+
+ /* We are setting a breakpoint in Thumb code that could potentially
+ contain an IT block. The first step is to find how much Thumb
+ code there is; we do not need to read outside of known Thumb
+ sequences. */
+ map_type = arm_find_mapping_symbol (bpaddr, &boundary);
+ if (map_type == 0)
+ /* Thumb-2 code must have mapping symbols to have a chance. */
+ return bpaddr;
+
+ bpaddr = gdbarch_addr_bits_remove (gdbarch, bpaddr);
+
+ if (find_pc_partial_function (bpaddr, NULL, &func_start, NULL)
+ && func_start > boundary)
+ boundary = func_start;
+
+ /* Search for a candidate IT instruction. We have to do some fancy
+ footwork to distinguish a real IT instruction from the second
+ half of a 32-bit instruction, but there is no need for that if
+ there's no candidate. */
+ buf_len = min (bpaddr - boundary, MAX_IT_BLOCK_PREFIX);
+ if (buf_len == 0)
+ /* No room for an IT instruction. */
+ return bpaddr;
+
+ buf = xmalloc (buf_len);
+ if (target_read_memory (bpaddr - buf_len, buf, buf_len) != 0)
+ return bpaddr;
+ any = 0;
+ for (i = 0; i < buf_len; i += 2)
+ {
+ unsigned short inst1 = extract_unsigned_integer (&buf[i], 2, order);
+ if ((inst1 & 0xff00) == 0xbf00 && (inst1 & 0x000f) != 0)
+ {
+ any = 1;
+ break;
+ }
+ }
+ if (any == 0)
+ {
+ xfree (buf);
+ return bpaddr;
+ }
+
+ /* OK, the code bytes before this instruction contain at least one
+ halfword which resembles an IT instruction. We know that it's
+ Thumb code, but there are still two possibilities. Either the
+ halfword really is an IT instruction, or it is the second half of
+ a 32-bit Thumb instruction. The only way we can tell is to
+ scan forwards from a known instruction boundary. */
+ if (bpaddr - boundary > IT_SCAN_THRESHOLD)
+ {
+ int definite;
+
+ /* There's a lot of code before this instruction. Start with an
+ optimistic search; it's easy to recognize halfwords that can
+ not be the start of a 32-bit instruction, and use that to
+ lock on to the instruction boundaries. */
+ buf = extend_buffer_earlier (buf, bpaddr, buf_len, IT_SCAN_THRESHOLD);
+ if (buf == NULL)
+ return bpaddr;
+ buf_len = IT_SCAN_THRESHOLD;
+
+ definite = 0;
+ for (i = 0; i < buf_len - sizeof (buf) && ! definite; i += 2)
+ {
+ unsigned short inst1 = extract_unsigned_integer (&buf[i], 2, order);
+ if (thumb_insn_size (inst1) == 2)
+ {
+ definite = 1;
+ break;
+ }
+ }
+
+ /* At this point, if DEFINITE, BUF[I] is the first place we
+ are sure that we know the instruction boundaries, and it is far
+ enough from BPADDR that we could not miss an IT instruction
+ affecting BPADDR. If ! DEFINITE, give up - start from a
+ known boundary. */
+ if (! definite)
+ {
+ buf = extend_buffer_earlier (buf, bpaddr, buf_len, bpaddr - boundary);
+ if (buf == NULL)
+ return bpaddr;
+ buf_len = bpaddr - boundary;
+ i = 0;
+ }
+ }
+ else
+ {
+ buf = extend_buffer_earlier (buf, bpaddr, buf_len, bpaddr - boundary);
+ if (buf == NULL)
+ return bpaddr;
+ buf_len = bpaddr - boundary;
+ i = 0;
+ }
+
+ /* Scan forwards. Find the last IT instruction before BPADDR. */
+ last_it = -1;
+ last_it_count = 0;
+ while (i < buf_len)
+ {
+ unsigned short inst1 = extract_unsigned_integer (&buf[i], 2, order);
+ last_it_count--;
+ if ((inst1 & 0xff00) == 0xbf00 && (inst1 & 0x000f) != 0)
+ {
+ last_it = i;
+ if (inst1 & 0x0001)
+ last_it_count = 4;
+ else if (inst1 & 0x0002)
+ last_it_count = 3;
+ else if (inst1 & 0x0004)
+ last_it_count = 2;
+ else
+ last_it_count = 1;
+ }
+ i += thumb_insn_size (inst1);
+ }
+
+ xfree (buf);
+
+ if (last_it == -1)
+ /* There wasn't really an IT instruction after all. */
+ return bpaddr;
+
+ if (last_it_count < 1)
+ /* It was too far away. */
+ return bpaddr;
+
+ /* This really is a trouble spot. Move the breakpoint to the IT
+ instruction. */
+ return bpaddr - buf_len + last_it;
+}
+
+/* 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, 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,
+ 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,
+ 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, 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, 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