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. */
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];
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);
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
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);
CORE_ADDR func_addr, limit_pc;
struct symtab_and_line sal;
- /* If we're in a dummy frame, don't even try to skip the prologue. */
- if (deprecated_pc_in_call_dummy (gdbarch, pc))
- return pc;
-
/* See if we can determine the end of the prologue via the symbol table.
If so, then return either PC, or the PC after the prologue, whichever
is greater. */
{
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)
- return max (pc, post_prologue_pc);
+ {
+ 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);
+
+ if (analyzed_limit != post_prologue_pc)
+ return func_addr;
+
+ return post_prologue_pc;
+ }
}
/* Can't determine prologue from the symbol table, need to examine
thumb_analyze_prologue (gdbarch, prologue_start, prologue_end, cache);
}
-/* This function decodes an ARM function prologue to determine:
- 1) the size of the stack frame
- 2) which registers are saved on it
- 3) the offsets of saved regs
- 4) the offset from the stack pointer to the frame pointer
- This information is stored in the "extra" fields of the frame_info.
-
- There are two basic forms for the ARM prologue. The fixed argument
- function call will look like:
-
- mov ip, sp
- stmfd sp!, {fp, ip, lr, pc}
- sub fp, ip, #4
- [sub sp, sp, #4]
-
- Which would create this stack frame (offsets relative to FP):
- IP -> 4 (caller's stack)
- FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
- -4 LR (return address in caller)
- -8 IP (copy of caller's SP)
- -12 FP (caller's FP)
- SP -> -28 Local variables
-
- The frame size would thus be 32 bytes, and the frame offset would be
- 28 bytes. The stmfd call can also save any of the vN registers it
- plans to use, which increases the frame size accordingly.
-
- Note: The stored PC is 8 off of the STMFD instruction that stored it
- because the ARM Store instructions always store PC + 8 when you read
- the PC register.
-
- A variable argument function call will look like:
-
- mov ip, sp
- stmfd sp!, {a1, a2, a3, a4}
- stmfd sp!, {fp, ip, lr, pc}
- sub fp, ip, #20
-
- Which would create this stack frame (offsets relative to FP):
- IP -> 20 (caller's stack)
- 16 A4
- 12 A3
- 8 A2
- 4 A1
- FP -> 0 PC (points to address of stmfd instruction + 8 in callee)
- -4 LR (return address in caller)
- -8 IP (copy of caller's SP)
- -12 FP (caller's FP)
- SP -> -28 Local variables
-
- The frame size would thus be 48 bytes, and the frame offset would be
- 28 bytes.
-
- There is another potential complication, which is that the optimizer
- will try to separate the store of fp in the "stmfd" instruction from
- the "sub fp, ip, #NN" instruction. Almost anything can be there, so
- we just key on the stmfd, and then scan for the "sub fp, ip, #NN"...
-
- Also, note, the original version of the ARM toolchain claimed that there
- should be an
-
- instruction at the end of the prologue. I have never seen GCC produce
- this, and the ARM docs don't mention it. We still test for it below in
- case it happens...
-
- */
+/* Return 1 if THIS_INSTR might change control flow, 0 otherwise. */
-static void
-arm_scan_prologue (struct frame_info *this_frame,
- struct arm_prologue_cache *cache)
+static int
+arm_instruction_changes_pc (uint32_t this_instr)
{
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
- int regno;
- CORE_ADDR prologue_start, prologue_end, current_pc;
- CORE_ADDR prev_pc = get_frame_pc (this_frame);
- CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
- pv_t regs[ARM_FPS_REGNUM];
- struct pv_area *stack;
- struct cleanup *back_to;
- CORE_ADDR offset;
+ 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;
- /* Assume there is no frame until proven otherwise. */
- cache->framereg = ARM_SP_REGNUM;
- cache->framesize = 0;
+ /* Otherwise, miscellaneous instructions. */
- /* Check for Thumb prologue. */
- if (arm_frame_is_thumb (this_frame))
- {
- thumb_scan_prologue (gdbarch, prev_pc, block_addr, cache);
- return;
- }
+ /* BX <reg>, BXJ <reg>, BLX <reg> */
+ if (bits (this_instr, 4, 27) == 0x12fff1
+ || bits (this_instr, 4, 27) == 0x12fff2
+ || bits (this_instr, 4, 27) == 0x12fff3)
+ return 1;
- /* 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:
+ /* Other miscellaneous instructions are unpredictable if they
+ modify PC. */
+ return 0;
+ }
+ /* Data processing instruction. Fall through. */
- struct symtab_and_line sal = find_pc_line (prologue_start, 0);
+ case 0x1:
+ if (bits (this_instr, 12, 15) == 15)
+ return 1;
+ else
+ return 0;
- if (sal.line == 0)
- prologue_end = prev_pc;
- else if (sal.end < prologue_end)
- prologue_end = sal.end;
+ case 0x2:
+ case 0x3:
+ /* Media instructions and architecturally undefined instructions. */
+ if (bits (this_instr, 25, 27) == 3 && bit (this_instr, 4) == 1)
+ return 0;
- 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.
+ /* Stores. */
+ if (bit (this_instr, 20) == 0)
+ return 0;
- 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;
+ /* Loads. */
+ if (bits (this_instr, 12, 15) == ARM_PC_REGNUM)
+ return 1;
+ else
+ return 0;
- 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. */
- }
- }
+ case 0x4:
+ /* Load/store multiple. */
+ if (bit (this_instr, 20) == 1 && bit (this_instr, 15) == 1)
+ return 1;
+ else
+ return 0;
- if (prev_pc < prologue_end)
- prologue_end = prev_pc;
+ 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");
+ }
+}
+
+/* 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.
+
+ 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). */
+
+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,
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. */
for (regno = 0; regno < ARM_FPS_REGNUM; regno++)
regs[regno] = pv_register (regno, 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));
- regs[ARM_IP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], 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));
- regs[ARM_IP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -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]! */
{
if (pv_area_store_would_trash (stack, regs[ARM_SP_REGNUM]))
break;
regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -4);
- pv_area_store (stack, regs[ARM_SP_REGNUM], 4, regs[ARM_LR_REGNUM]);
+ pv_area_store (stack, regs[ARM_SP_REGNUM], 4,
+ regs[bits (insn, 12, 15)]);
continue;
}
else if ((insn & 0xffff0000) == 0xe92d0000)
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] */
+ 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] */
+ 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 */
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;
+ }
}
+ 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. */
- cache->framereg = ARM_FP_REGNUM;
- cache->framesize = -regs[ARM_FP_REGNUM].k;
+ 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. */
- cache->framereg = ARM_SP_REGNUM;
- cache->framesize = -regs[ARM_SP_REGNUM].k;
+ framereg = ARM_SP_REGNUM;
+ framesize = -regs[ARM_SP_REGNUM].k;
}
else
{
/* We're just out of luck. We don't know where the frame is. */
- cache->framereg = -1;
- cache->framesize = 0;
+ framereg = -1;
+ framesize = 0;
}
- for (regno = 0; regno < ARM_FPS_REGNUM; regno++)
- if (pv_area_find_reg (stack, gdbarch, regno, &offset))
- cache->saved_regs[regno].addr = offset;
+ 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 *
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)
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)
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