/* Common target dependent code for GDB on ARM systems. Copyright (C) 1988-2021 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "defs.h" #include /* XXX for isupper (). */ #include "frame.h" #include "inferior.h" #include "infrun.h" #include "gdbcmd.h" #include "gdbcore.h" #include "dis-asm.h" /* For register styles. */ #include "disasm.h" #include "regcache.h" #include "reggroups.h" #include "target-float.h" #include "value.h" #include "arch-utils.h" #include "osabi.h" #include "frame-unwind.h" #include "frame-base.h" #include "trad-frame.h" #include "objfiles.h" #include "dwarf2/frame.h" #include "gdbtypes.h" #include "prologue-value.h" #include "remote.h" #include "target-descriptions.h" #include "user-regs.h" #include "observable.h" #include "count-one-bits.h" #include "arch/arm.h" #include "arch/arm-get-next-pcs.h" #include "arm-tdep.h" #include "gdb/sim-arm.h" #include "elf-bfd.h" #include "coff/internal.h" #include "elf/arm.h" #include "record.h" #include "record-full.h" #include #include "producer.h" #if GDB_SELF_TEST #include "gdbsupport/selftest.h" #endif static bool arm_debug; /* Print an "arm" debug statement. */ #define arm_debug_printf(fmt, ...) \ debug_prefixed_printf_cond (arm_debug, "arm", fmt, ##__VA_ARGS__) /* Macros for setting and testing a bit in a minimal symbol that marks it as Thumb function. The MSB of the minimal symbol's "info" field is used for this purpose. MSYMBOL_SET_SPECIAL Actually sets the "special" bit. MSYMBOL_IS_SPECIAL Tests the "special" bit in a minimal symbol. */ #define MSYMBOL_SET_SPECIAL(msym) \ MSYMBOL_TARGET_FLAG_1 (msym) = 1 #define MSYMBOL_IS_SPECIAL(msym) \ MSYMBOL_TARGET_FLAG_1 (msym) struct arm_mapping_symbol { CORE_ADDR value; char type; bool operator< (const arm_mapping_symbol &other) const { return this->value < other.value; } }; typedef std::vector arm_mapping_symbol_vec; struct arm_per_bfd { explicit arm_per_bfd (size_t num_sections) : section_maps (new arm_mapping_symbol_vec[num_sections]), section_maps_sorted (new bool[num_sections] ()) {} DISABLE_COPY_AND_ASSIGN (arm_per_bfd); /* Information about mapping symbols ($a, $d, $t) in the objfile. The format is an array of vectors of arm_mapping_symbols, there is one vector for each section of the objfile (the array is index by BFD section index). For each section, the vector of arm_mapping_symbol is sorted by symbol value (address). */ std::unique_ptr section_maps; /* For each corresponding element of section_maps above, is this vector sorted. */ std::unique_ptr section_maps_sorted; }; /* Per-bfd data used for mapping symbols. */ static bfd_key arm_bfd_data_key; /* The list of available "set arm ..." and "show arm ..." commands. */ static struct cmd_list_element *setarmcmdlist = NULL; static struct cmd_list_element *showarmcmdlist = NULL; /* The type of floating-point to use. Keep this in sync with enum arm_float_model, and the help string in _initialize_arm_tdep. */ static const char *const fp_model_strings[] = { "auto", "softfpa", "fpa", "softvfp", "vfp", NULL }; /* A variable that can be configured by the user. */ static enum arm_float_model arm_fp_model = ARM_FLOAT_AUTO; static const char *current_fp_model = "auto"; /* The ABI to use. Keep this in sync with arm_abi_kind. */ static const char *const arm_abi_strings[] = { "auto", "APCS", "AAPCS", NULL }; /* A variable that can be configured by the user. */ static enum arm_abi_kind arm_abi_global = ARM_ABI_AUTO; static const char *arm_abi_string = "auto"; /* The execution mode to assume. */ static const char *const arm_mode_strings[] = { "auto", "arm", "thumb", NULL }; static const char *arm_fallback_mode_string = "auto"; static const char *arm_force_mode_string = "auto"; /* The standard register names, and all the valid aliases for them. Note that `fp', `sp' and `pc' are not added in this alias list, because they have been added as builtin user registers in std-regs.c:_initialize_frame_reg. */ static const struct { const char *name; int regnum; } arm_register_aliases[] = { /* Basic register numbers. */ { "r0", 0 }, { "r1", 1 }, { "r2", 2 }, { "r3", 3 }, { "r4", 4 }, { "r5", 5 }, { "r6", 6 }, { "r7", 7 }, { "r8", 8 }, { "r9", 9 }, { "r10", 10 }, { "r11", 11 }, { "r12", 12 }, { "r13", 13 }, { "r14", 14 }, { "r15", 15 }, /* Synonyms (argument and variable registers). */ { "a1", 0 }, { "a2", 1 }, { "a3", 2 }, { "a4", 3 }, { "v1", 4 }, { "v2", 5 }, { "v3", 6 }, { "v4", 7 }, { "v5", 8 }, { "v6", 9 }, { "v7", 10 }, { "v8", 11 }, /* Other platform-specific names for r9. */ { "sb", 9 }, { "tr", 9 }, /* Special names. */ { "ip", 12 }, { "lr", 14 }, /* Names used by GCC (not listed in the ARM EABI). */ { "sl", 10 }, /* A special name from the older ATPCS. */ { "wr", 7 }, }; static const char *const arm_register_names[] = {"r0", "r1", "r2", "r3", /* 0 1 2 3 */ "r4", "r5", "r6", "r7", /* 4 5 6 7 */ "r8", "r9", "r10", "r11", /* 8 9 10 11 */ "r12", "sp", "lr", "pc", /* 12 13 14 15 */ "f0", "f1", "f2", "f3", /* 16 17 18 19 */ "f4", "f5", "f6", "f7", /* 20 21 22 23 */ "fps", "cpsr" }; /* 24 25 */ /* Holds the current set of options to be passed to the disassembler. */ static char *arm_disassembler_options; /* Valid register name styles. */ static const char **valid_disassembly_styles; /* Disassembly style to use. Default to "std" register names. */ static const char *disassembly_style; /* All possible arm target descriptors. */ static struct target_desc *tdesc_arm_list[ARM_FP_TYPE_INVALID]; static struct target_desc *tdesc_arm_mprofile_list[ARM_M_TYPE_INVALID]; /* This is used to keep the bfd arch_info in sync with the disassembly style. */ static void set_disassembly_style_sfunc (const char *, int, struct cmd_list_element *); static void show_disassembly_style_sfunc (struct ui_file *, int, struct cmd_list_element *, const char *); static enum register_status arm_neon_quad_read (struct gdbarch *gdbarch, readable_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); static CORE_ADDR arm_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self); /* get_next_pcs operations. */ static struct arm_get_next_pcs_ops arm_get_next_pcs_ops = { arm_get_next_pcs_read_memory_unsigned_integer, arm_get_next_pcs_syscall_next_pc, arm_get_next_pcs_addr_bits_remove, arm_get_next_pcs_is_thumb, NULL, }; struct arm_prologue_cache { /* The stack pointer at the time this frame was created; i.e. the caller's stack pointer when this function was called. It is used to identify this frame. */ CORE_ADDR prev_sp; /* The frame base for this frame is just prev_sp - frame size. FRAMESIZE is the distance from the frame pointer to the initial stack pointer. */ int framesize; /* The register used to hold the frame pointer for this frame. */ int framereg; /* Saved register offsets. */ trad_frame_saved_reg *saved_regs; }; namespace { /* Abstract class to read ARM instructions from memory. */ class arm_instruction_reader { public: /* Read a 4 bytes instruction from memory using the BYTE_ORDER endianness. */ virtual uint32_t read (CORE_ADDR memaddr, bfd_endian byte_order) const = 0; }; /* Read instructions from target memory. */ class target_arm_instruction_reader : public arm_instruction_reader { public: uint32_t read (CORE_ADDR memaddr, bfd_endian byte_order) const override { return read_code_unsigned_integer (memaddr, 4, byte_order); } }; } /* namespace */ static CORE_ADDR arm_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR prologue_start, CORE_ADDR prologue_end, struct arm_prologue_cache *cache, const arm_instruction_reader &insn_reader); /* 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 /* See arm-tdep.h. */ bool arm_apcs_32 = true; /* Return the bit mask in ARM_PS_REGNUM that indicates Thumb mode. */ int arm_psr_thumb_bit (struct gdbarch *gdbarch) { if (gdbarch_tdep (gdbarch)->is_m) return XPSR_T; else return CPSR_T; } /* Determine if the processor is currently executing in Thumb mode. */ int arm_is_thumb (struct regcache *regcache) { ULONGEST cpsr; ULONGEST t_bit = arm_psr_thumb_bit (regcache->arch ()); cpsr = regcache_raw_get_unsigned (regcache, ARM_PS_REGNUM); return (cpsr & t_bit) != 0; } /* Determine if FRAME is executing in Thumb mode. */ int arm_frame_is_thumb (struct frame_info *frame) { CORE_ADDR cpsr; ULONGEST t_bit = arm_psr_thumb_bit (get_frame_arch (frame)); /* 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 & t_bit) != 0; } /* 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) { arm_per_bfd *data = arm_bfd_data_key.get (sec->objfile->obfd); if (data != NULL) { unsigned int section_idx = sec->the_bfd_section->index; arm_mapping_symbol_vec &map = data->section_maps[section_idx]; /* Sort the vector on first use. */ if (!data->section_maps_sorted[section_idx]) { std::sort (map.begin (), map.end ()); data->section_maps_sorted[section_idx] = true; } arm_mapping_symbol map_key = { memaddr - sec->addr (), 0 }; arm_mapping_symbol_vec::const_iterator it = std::lower_bound (map.begin (), map.end (), map_key); /* std::lower_bound finds the earliest ordered insertion point. If the symbol at this position starts at this exact address, we use that; otherwise, the preceding mapping symbol covers this address. */ if (it < map.end ()) { if (it->value == map_key.value) { if (start) *start = it->value + sec->addr (); return it->type; } } if (it > map.begin ()) { arm_mapping_symbol_vec::const_iterator prev_it = it - 1; if (start) *start = prev_it->value + sec->addr (); return prev_it->type; } } } return 0; } /* Determine if the program counter specified in MEMADDR is in a Thumb function. This function should be called for addresses unrelated to any executing frame; otherwise, prefer arm_frame_is_thumb. */ int arm_pc_is_thumb (struct gdbarch *gdbarch, CORE_ADDR memaddr) { struct bound_minimal_symbol sym; char type; arm_displaced_step_copy_insn_closure *dsc = nullptr; if (gdbarch_displaced_step_copy_insn_closure_by_addr_p (gdbarch)) dsc = ((arm_displaced_step_copy_insn_closure * ) gdbarch_displaced_step_copy_insn_closure_by_addr (gdbarch, current_inferior (), memaddr)); /* If checking the mode of displaced instruction in copy area, the mode should be determined by instruction on the original address. */ if (dsc) { displaced_debug_printf ("check mode of %.8lx instead of %.8lx", (unsigned long) dsc->insn_addr, (unsigned long) memaddr); memaddr = dsc->insn_addr; } /* 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; /* ARM v6-M and v7-M are always in Thumb mode. */ if (gdbarch_tdep (gdbarch)->is_m) 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.minsym) return (MSYMBOL_IS_SPECIAL (sym.minsym)); /* If the user wants to override the fallback mode, let them. */ if (strcmp (arm_fallback_mode_string, "arm") == 0) return 0; if (strcmp (arm_fallback_mode_string, "thumb") == 0) return 1; /* If we couldn't find any symbol, but we're talking to a running target, then trust the current value of $cpsr. This lets "display/i $pc" always show the correct mode (though if there is a symbol table we will not reach here, so it still may not be displayed in the mode it will be executed). */ if (target_has_registers ()) return arm_frame_is_thumb (get_current_frame ()); /* Otherwise we're out of luck; we assume ARM. */ return 0; } /* Determine if the address specified equals any of these magic return values, called EXC_RETURN, defined by the ARM v6-M, v7-M and v8-M architectures. From ARMv6-M Reference Manual B1.5.8 Table B1-5 Exception return behavior EXC_RETURN Return To Return Stack 0xFFFFFFF1 Handler mode Main 0xFFFFFFF9 Thread mode Main 0xFFFFFFFD Thread mode Process From ARMv7-M Reference Manual B1.5.8 Table B1-8 EXC_RETURN definition of exception return behavior, no FP EXC_RETURN Return To Return Stack 0xFFFFFFF1 Handler mode Main 0xFFFFFFF9 Thread mode Main 0xFFFFFFFD Thread mode Process Table B1-9 EXC_RETURN definition of exception return behavior, with FP EXC_RETURN Return To Return Stack Frame Type 0xFFFFFFE1 Handler mode Main Extended 0xFFFFFFE9 Thread mode Main Extended 0xFFFFFFED Thread mode Process Extended 0xFFFFFFF1 Handler mode Main Basic 0xFFFFFFF9 Thread mode Main Basic 0xFFFFFFFD Thread mode Process Basic For more details see "B1.5.8 Exception return behavior" in both ARMv6-M and ARMv7-M Architecture Reference Manuals. In the ARMv8-M Architecture Technical Reference also adds for implementations without the Security Extension: EXC_RETURN Condition 0xFFFFFFB0 Return to Handler mode. 0xFFFFFFB8 Return to Thread mode using the main stack. 0xFFFFFFBC Return to Thread mode using the process stack. */ static int arm_m_addr_is_magic (CORE_ADDR addr) { switch (addr) { /* Values from ARMv8-M Architecture Technical Reference. */ case 0xffffffb0: case 0xffffffb8: case 0xffffffbc: /* Values from Tables in B1.5.8 the EXC_RETURN definitions of the exception return behavior. */ case 0xffffffe1: case 0xffffffe9: case 0xffffffed: case 0xfffffff1: case 0xfffffff9: case 0xfffffffd: /* Address is magic. */ return 1; default: /* Address is not magic. */ return 0; } } /* Remove useless bits from addresses in a running program. */ static CORE_ADDR arm_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val) { /* On M-profile devices, do not strip the low bit from EXC_RETURN (the magic exception return address). */ if (gdbarch_tdep (gdbarch)->is_m && arm_m_addr_is_magic (val)) return val; if (arm_apcs_32) return UNMAKE_THUMB_ADDR (val); else return (val & 0x03fffffc); } /* Return 1 if PC is the start of a compiler helper function which can be safely ignored during prologue skipping. IS_THUMB is true if the function is known to be a Thumb function due to the way it is being called. */ static int skip_prologue_function (struct gdbarch *gdbarch, CORE_ADDR pc, int is_thumb) { enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch); struct bound_minimal_symbol msym; msym = lookup_minimal_symbol_by_pc (pc); if (msym.minsym != NULL && BMSYMBOL_VALUE_ADDRESS (msym) == pc && msym.minsym->linkage_name () != NULL) { const char *name = msym.minsym->linkage_name (); /* 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 (startswith (name, "__truncdfsf2")) return 1; if (startswith (name, "__aeabi_d2f")) return 1; /* Internal functions related to thread-local storage. */ if (startswith (name, "__tls_get_addr")) return 1; if (startswith (name, "__aeabi_read_tp")) return 1; } else { /* If we run against a stripped glibc, we may be unable to identify special functions by name. Check for one important case, __aeabi_read_tp, by comparing the *code* against the default implementation (this is hand-written ARM assembler in glibc). */ if (!is_thumb && read_code_unsigned_integer (pc, 4, byte_order_for_code) == 0xe3e00a0f /* mov r0, #0xffff0fff */ && read_code_unsigned_integer (pc + 4, 4, byte_order_for_code) == 0xe240f01f) /* sub pc, r0, #31 */ return 1; } return 0; } /* Extract the immediate from instruction movw/movt of encoding T. INSN1 is the first 16-bit of instruction, and INSN2 is the second 16-bit of instruction. */ #define EXTRACT_MOVW_MOVT_IMM_T(insn1, insn2) \ ((bits ((insn1), 0, 3) << 12) \ | (bits ((insn1), 10, 10) << 11) \ | (bits ((insn2), 12, 14) << 8) \ | bits ((insn2), 0, 7)) /* Extract the immediate from instruction movw/movt of encoding A. INSN is the 32-bit instruction. */ #define EXTRACT_MOVW_MOVT_IMM_A(insn) \ ((bits ((insn), 16, 19) << 12) \ | bits ((insn), 0, 11)) /* Decode immediate value; implements ThumbExpandImmediate pseudo-op. */ static unsigned int thumb_expand_immediate (unsigned int imm) { unsigned int count = imm >> 7; if (count < 8) switch (count / 2) { case 0: return imm & 0xff; case 1: return (imm & 0xff) | ((imm & 0xff) << 16); case 2: return ((imm & 0xff) << 8) | ((imm & 0xff) << 24); case 3: return (imm & 0xff) | ((imm & 0xff) << 8) | ((imm & 0xff) << 16) | ((imm & 0xff) << 24); } return (0x80 | (imm & 0x7f)) << (32 - count); } /* Return 1 if the 16-bit Thumb instruction INSN restores SP in epilogue, 0 otherwise. */ static int thumb_instruction_restores_sp (unsigned short insn) { return (insn == 0x46bd /* mov sp, r7 */ || (insn & 0xff80) == 0xb000 /* add sp, imm */ || (insn & 0xfe00) == 0xbc00); /* pop */ } /* 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. 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]; CORE_ADDR offset; CORE_ADDR unrecognized_pc = 0; for (i = 0; i < 16; i++) regs[i] = pv_register (i, 0); pv_area stack (ARM_SP_REGNUM, gdbarch_addr_bit (gdbarch)); while (start < limit) { unsigned short insn; insn = read_code_unsigned_integer (start, 2, byte_order_for_code); if ((insn & 0xfe00) == 0xb400) /* push { rlist } */ { int regno; int mask; if (stack.store_would_trash (regs[ARM_SP_REGNUM])) break; /* Bits 0-7 contain a mask for registers R0-R7. Bit 8 says whether to save LR (R14). */ mask = (insn & 0xff) | ((insn & 0x100) << 6); /* Calculate offsets of saved R0-R7 and LR. */ for (regno = ARM_LR_REGNUM; regno >= 0; regno--) if (mask & (1 << regno)) { regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -4); stack.store (regs[ARM_SP_REGNUM], 4, regs[regno]); } } else if ((insn & 0xff80) == 0xb080) /* sub sp, #imm */ { offset = (insn & 0x7f) << 2; /* get scaled offset */ regs[ARM_SP_REGNUM] = pv_add_constant (regs[ARM_SP_REGNUM], -offset); } else if (thumb_instruction_restores_sp (insn)) { /* Don't scan past the epilogue. */ break; } 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); int src_reg = (insn & 0x78) >> 3; regs[dst_reg] = regs[src_reg]; } else if ((insn & 0xf800) == 0x9000) /* str rd, [sp, #off] */ { /* Handle stores to the stack. Normally pushes are used, but with GCC -mtpcs-frame, there may be other stores in the prologue to create the frame. */ int regno = (insn >> 8) & 0x7; pv_t addr; offset = (insn & 0xff) << 2; addr = pv_add_constant (regs[ARM_SP_REGNUM], offset); if (stack.store_would_trash (addr)) break; stack.store (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 (stack.store_would_trash (addr)) break; stack.store (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 (thumb_insn_size (insn) == 4) /* 32-bit Thumb-2 instructions. */ { unsigned short inst2; inst2 = read_code_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 (gdbarch, nextpc, bit (inst2, 12) != 0)) break; } else if ((insn & 0xffd0) == 0xe900 /* stmdb Rn{!}, { registers } */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) { pv_t addr = regs[bits (insn, 0, 3)]; int regno; if (stack.store_would_trash (addr)) break; /* Calculate offsets of saved registers. */ for (regno = ARM_LR_REGNUM; regno >= 0; regno--) if (inst2 & (1 << regno)) { addr = pv_add_constant (addr, -4); stack.store (addr, 4, regs[regno]); } if (insn & 0x0020) regs[bits (insn, 0, 3)] = addr; } else if ((insn & 0xff50) == 0xe940 /* strd Rt, Rt2, [Rn, #+/-imm]{!} */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) { int regno1 = bits (inst2, 12, 15); int regno2 = bits (inst2, 8, 11); pv_t addr = regs[bits (insn, 0, 3)]; offset = inst2 & 0xff; if (insn & 0x0080) addr = pv_add_constant (addr, offset); else addr = pv_add_constant (addr, -offset); if (stack.store_would_trash (addr)) break; stack.store (addr, 4, regs[regno1]); stack.store (pv_add_constant (addr, 4), 4, regs[regno2]); if (insn & 0x0020) regs[bits (insn, 0, 3)] = addr; } else if ((insn & 0xfff0) == 0xf8c0 /* str Rt,[Rn,+/-#imm]{!} */ && (inst2 & 0x0c00) == 0x0c00 && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) { int regno = bits (inst2, 12, 15); pv_t addr = regs[bits (insn, 0, 3)]; offset = inst2 & 0xff; if (inst2 & 0x0200) addr = pv_add_constant (addr, offset); else addr = pv_add_constant (addr, -offset); if (stack.store_would_trash (addr)) break; stack.store (addr, 4, regs[regno]); if (inst2 & 0x0100) regs[bits (insn, 0, 3)] = addr; } else if ((insn & 0xfff0) == 0xf8c0 /* str.w Rt,[Rn,#imm] */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) { int regno = bits (inst2, 12, 15); pv_t addr; offset = inst2 & 0xfff; addr = pv_add_constant (regs[bits (insn, 0, 3)], offset); if (stack.store_would_trash (addr)) break; stack.store (addr, 4, regs[regno]); } else if ((insn & 0xffd0) == 0xf880 /* str{bh}.w Rt,[Rn,#imm] */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Ignore stores of argument registers to the stack. */ ; else if ((insn & 0xffd0) == 0xf800 /* str{bh} Rt,[Rn,#+/-imm] */ && (inst2 & 0x0d00) == 0x0c00 && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Ignore stores of argument registers to the stack. */ ; else if ((insn & 0xffd0) == 0xe890 /* ldmia Rn[!], { registers } */ && (inst2 & 0x8000) == 0x0000 && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Ignore block loads from the stack, potentially copying parameters from memory. */ ; else if ((insn & 0xff70) == 0xe950 /* ldrd Rt, Rt2, [Rn, #+/-imm] */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Similarly ignore dual loads from the stack. */ ; else if ((insn & 0xfff0) == 0xf850 /* ldr Rt,[Rn,#+/-imm] */ && (inst2 & 0x0d00) == 0x0c00 && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Similarly ignore single loads from the stack. */ ; else if ((insn & 0xfff0) == 0xf8d0 /* ldr.w Rt,[Rn,#imm] */ && pv_is_register (regs[bits (insn, 0, 3)], ARM_SP_REGNUM)) /* Similarly ignore single loads from the stack. */ ; else if ((insn & 0xfbf0) == 0xf100 /* add.w Rd, Rn, #imm */ && (inst2 & 0x8000) == 0x0000) { unsigned int imm = ((bits (insn, 10, 10) << 11) | (bits (inst2, 12, 14) << 8) | bits (inst2, 0, 7)); regs[bits (inst2, 8, 11)] = pv_add_constant (regs[bits (insn, 0, 3)], thumb_expand_immediate (imm)); } else if ((insn & 0xfbf0) == 0xf200 /* addw Rd, Rn, #imm */ && (inst2 & 0x8000) == 0x0000) { unsigned int imm = ((bits (insn, 10, 10) << 11) | (bits (inst2, 12, 14) << 8) | bits (inst2, 0, 7)); regs[bits (inst2, 8, 11)] = pv_add_constant (regs[bits (insn, 0, 3)], imm); } else if ((insn & 0xfbf0) == 0xf1a0 /* sub.w Rd, Rn, #imm */ && (inst2 & 0x8000) == 0x0000) { unsigned int imm = ((bits (insn, 10, 10) << 11) | (bits (inst2, 12, 14) << 8) | bits (inst2, 0, 7)); regs[bits (inst2, 8, 11)] = pv_add_constant (regs[bits (insn, 0, 3)], - (CORE_ADDR) thumb_expand_immediate (imm)); } else if ((insn & 0xfbf0) == 0xf2a0 /* subw Rd, Rn, #imm */ && (inst2 & 0x8000) == 0x0000) { unsigned int imm = ((bits (insn, 10, 10) << 11) | (bits (inst2, 12, 14) << 8) | bits (inst2, 0, 7)); regs[bits (inst2, 8, 11)] = pv_add_constant (regs[bits (insn, 0, 3)], - (CORE_ADDR) imm); } else if ((insn & 0xfbff) == 0xf04f) /* mov.w Rd, #const */ { unsigned int imm = ((bits (insn, 10, 10) << 11) | (bits (inst2, 12, 14) << 8) | bits (inst2, 0, 7)); regs[bits (inst2, 8, 11)] = pv_constant (thumb_expand_immediate (imm)); } else if ((insn & 0xfbf0) == 0xf240) /* movw Rd, #const */ { unsigned int imm = EXTRACT_MOVW_MOVT_IMM_T (insn, inst2); regs[bits (inst2, 8, 11)] = pv_constant (imm); } else if (insn == 0xea5f /* mov.w Rd,Rm */ && (inst2 & 0xf0f0) == 0) { int dst_reg = (inst2 & 0x0f00) >> 8; int src_reg = inst2 & 0xf; regs[dst_reg] = regs[src_reg]; } else if ((insn & 0xff7f) == 0xf85f) /* ldr.w Rt,