diff options
Diffstat (limited to 'gdb/arm-tdep.c')
| -rw-r--r-- | gdb/arm-tdep.c | 735 |
1 files changed, 529 insertions, 206 deletions
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index c28fd04..f6a8436 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -235,6 +235,11 @@ 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. */ @@ -424,15 +429,59 @@ 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]; @@ -483,9 +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); @@ -508,6 +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 @@ -520,6 +714,10 @@ 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); @@ -583,10 +781,6 @@ arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) CORE_ADDR func_addr, limit_pc; struct symtab_and_line sal; - /* If we're in a dummy frame, don't even try to skip the prologue. */ - if (deprecated_pc_in_call_dummy (gdbarch, pc)) - return pc; - /* See if we can determine the end of the prologue via the symbol table. If so, then return either PC, or the PC after the prologue, whichever is greater. */ @@ -594,8 +788,45 @@ arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) { 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 @@ -724,167 +955,124 @@ thumb_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR prev_pc, thumb_analyze_prologue (gdbarch, prologue_start, prologue_end, cache); } -/* This function decodes an ARM function prologue to determine: - 1) the size of the stack frame - 2) which registers are saved on it - 3) the offsets of saved regs - 4) the offset from the stack pointer to the frame pointer - This information is stored in the "extra" fields of the frame_info. - - There are two basic forms for the ARM prologue. The fixed argument - function call will look like: - - mov ip, sp - stmfd sp!, {fp, ip, lr, pc} - sub fp, ip, #4 - [sub sp, sp, #4] - - Which would create this stack frame (offsets relative to FP): - IP -> 4 (caller's stack) - FP -> 0 PC (points to address of stmfd instruction + 8 in callee) - -4 LR (return address in caller) - -8 IP (copy of caller's SP) - -12 FP (caller's FP) - SP -> -28 Local variables - - The frame size would thus be 32 bytes, and the frame offset would be - 28 bytes. The stmfd call can also save any of the vN registers it - plans to use, which increases the frame size accordingly. - - Note: The stored PC is 8 off of the STMFD instruction that stored it - because the ARM Store instructions always store PC + 8 when you read - the PC register. - - A variable argument function call will look like: - - mov ip, sp - stmfd sp!, {a1, a2, a3, a4} - stmfd sp!, {fp, ip, lr, pc} - sub fp, ip, #20 - - Which would create this stack frame (offsets relative to FP): - IP -> 20 (caller's stack) - 16 A4 - 12 A3 - 8 A2 - 4 A1 - FP -> 0 PC (points to address of stmfd instruction + 8 in callee) - -4 LR (return address in caller) - -8 IP (copy of caller's SP) - -12 FP (caller's FP) - SP -> -28 Local variables - - The frame size would thus be 48 bytes, and the frame offset would be - 28 bytes. - - There is another potential complication, which is that the optimizer - will try to separate the store of fp in the "stmfd" instruction from - the "sub fp, ip, #NN" instruction. Almost anything can be there, so - we just key on the stmfd, and then scan for the "sub fp, ip, #NN"... - - Also, note, the original version of the ARM toolchain claimed that there - should be an - - instruction at the end of the prologue. I have never seen GCC produce - this, and the ARM docs don't mention it. We still test for it below in - case it happens... - - */ +/* 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, @@ -892,18 +1080,7 @@ arm_scan_prologue (struct frame_info *this_frame, 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); @@ -922,28 +1099,33 @@ arm_scan_prologue (struct frame_info *this_frame, 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) @@ -964,20 +1146,26 @@ arm_scan_prologue (struct frame_info *this_frame, 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 */ @@ -1035,42 +1223,188 @@ arm_scan_prologue (struct frame_info *this_frame, 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 * @@ -2231,16 +2565,6 @@ condition_true (unsigned long cond, unsigned long status_reg) 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) @@ -2259,8 +2583,7 @@ 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) |