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- /* Target-dependent code for the VAX.
- Copyright (C) 1986-2022 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 <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "arch-utils.h"
- #include "dis-asm.h"
- #include "frame.h"
- #include "frame-base.h"
- #include "frame-unwind.h"
- #include "gdbcore.h"
- #include "gdbtypes.h"
- #include "osabi.h"
- #include "regcache.h"
- #include "regset.h"
- #include "trad-frame.h"
- #include "value.h"
- #include "vax-tdep.h"
- /* Return the name of register REGNUM. */
- static const char *
- vax_register_name (struct gdbarch *gdbarch, int regnum)
- {
- static const char *register_names[] =
- {
- "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
- "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc",
- "ps",
- };
- if (regnum >= 0 && regnum < ARRAY_SIZE (register_names))
- return register_names[regnum];
- return NULL;
- }
- /* Return the GDB type object for the "standard" data type of data in
- register REGNUM. */
- static struct type *
- vax_register_type (struct gdbarch *gdbarch, int regnum)
- {
- return builtin_type (gdbarch)->builtin_int;
- }
- /* Core file support. */
- /* Supply register REGNUM from the buffer specified by GREGS and LEN
- in the general-purpose register set REGSET to register cache
- REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
- static void
- vax_supply_gregset (const struct regset *regset, struct regcache *regcache,
- int regnum, const void *gregs, size_t len)
- {
- const gdb_byte *regs = (const gdb_byte *) gregs;
- int i;
- for (i = 0; i < VAX_NUM_REGS; i++)
- {
- if (regnum == i || regnum == -1)
- regcache->raw_supply (i, regs + i * 4);
- }
- }
- /* VAX register set. */
- static const struct regset vax_gregset =
- {
- NULL,
- vax_supply_gregset
- };
- /* Iterate over core file register note sections. */
- static void
- vax_iterate_over_regset_sections (struct gdbarch *gdbarch,
- iterate_over_regset_sections_cb *cb,
- void *cb_data,
- const struct regcache *regcache)
- {
- cb (".reg", VAX_NUM_REGS * 4, VAX_NUM_REGS * 4, &vax_gregset, NULL, cb_data);
- }
- /* The VAX UNIX calling convention uses R1 to pass a structure return
- value address instead of passing it as a first (hidden) argument as
- the VMS calling convention suggests. */
- static CORE_ADDR
- vax_store_arguments (struct regcache *regcache, int nargs,
- struct value **args, CORE_ADDR sp)
- {
- struct gdbarch *gdbarch = regcache->arch ();
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- gdb_byte buf[4];
- int count = 0;
- int i;
- /* We create an argument list on the stack, and make the argument
- pointer to it. */
- /* Push arguments in reverse order. */
- for (i = nargs - 1; i >= 0; i--)
- {
- int len = TYPE_LENGTH (value_enclosing_type (args[i]));
- sp -= (len + 3) & ~3;
- count += (len + 3) / 4;
- write_memory (sp, value_contents_all (args[i]).data (), len);
- }
- /* Push argument count. */
- sp -= 4;
- store_unsigned_integer (buf, 4, byte_order, count);
- write_memory (sp, buf, 4);
- /* Update the argument pointer. */
- store_unsigned_integer (buf, 4, byte_order, sp);
- regcache->cooked_write (VAX_AP_REGNUM, buf);
- return sp;
- }
- static CORE_ADDR
- vax_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
- struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
- struct value **args, CORE_ADDR sp,
- function_call_return_method return_method,
- CORE_ADDR struct_addr)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- CORE_ADDR fp = sp;
- gdb_byte buf[4];
- /* Set up the function arguments. */
- sp = vax_store_arguments (regcache, nargs, args, sp);
- /* Store return value address. */
- if (return_method == return_method_struct)
- regcache_cooked_write_unsigned (regcache, VAX_R1_REGNUM, struct_addr);
- /* Store return address in the PC slot. */
- sp -= 4;
- store_unsigned_integer (buf, 4, byte_order, bp_addr);
- write_memory (sp, buf, 4);
- /* Store the (fake) frame pointer in the FP slot. */
- sp -= 4;
- store_unsigned_integer (buf, 4, byte_order, fp);
- write_memory (sp, buf, 4);
- /* Skip the AP slot. */
- sp -= 4;
- /* Store register save mask and control bits. */
- sp -= 4;
- store_unsigned_integer (buf, 4, byte_order, 0);
- write_memory (sp, buf, 4);
- /* Store condition handler. */
- sp -= 4;
- store_unsigned_integer (buf, 4, byte_order, 0);
- write_memory (sp, buf, 4);
- /* Update the stack pointer and frame pointer. */
- store_unsigned_integer (buf, 4, byte_order, sp);
- regcache->cooked_write (VAX_SP_REGNUM, buf);
- regcache->cooked_write (VAX_FP_REGNUM, buf);
- /* Return the saved (fake) frame pointer. */
- return fp;
- }
- static struct frame_id
- vax_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
- {
- CORE_ADDR fp;
- fp = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM);
- return frame_id_build (fp, get_frame_pc (this_frame));
- }
- static enum return_value_convention
- vax_return_value (struct gdbarch *gdbarch, struct value *function,
- struct type *type, struct regcache *regcache,
- gdb_byte *readbuf, const gdb_byte *writebuf)
- {
- int len = TYPE_LENGTH (type);
- gdb_byte buf[8];
- if (type->code () == TYPE_CODE_STRUCT
- || type->code () == TYPE_CODE_UNION
- || type->code () == TYPE_CODE_ARRAY)
- {
- /* The default on VAX is to return structures in static memory.
- Consequently a function must return the address where we can
- find the return value. */
- if (readbuf)
- {
- ULONGEST addr;
- regcache_raw_read_unsigned (regcache, VAX_R0_REGNUM, &addr);
- read_memory (addr, readbuf, len);
- }
- return RETURN_VALUE_ABI_RETURNS_ADDRESS;
- }
- if (readbuf)
- {
- /* Read the contents of R0 and (if necessary) R1. */
- regcache->cooked_read (VAX_R0_REGNUM, buf);
- if (len > 4)
- regcache->cooked_read (VAX_R1_REGNUM, buf + 4);
- memcpy (readbuf, buf, len);
- }
- if (writebuf)
- {
- /* Read the contents to R0 and (if necessary) R1. */
- memcpy (buf, writebuf, len);
- regcache->cooked_write (VAX_R0_REGNUM, buf);
- if (len > 4)
- regcache->cooked_write (VAX_R1_REGNUM, buf + 4);
- }
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
- /* Use the program counter to determine the contents and size of a
- breakpoint instruction. Return a pointer to a string of bytes that
- encode a breakpoint instruction, store the length of the string in
- *LEN and optionally adjust *PC to point to the correct memory
- location for inserting the breakpoint. */
- constexpr gdb_byte vax_break_insn[] = { 3 };
- typedef BP_MANIPULATION (vax_break_insn) vax_breakpoint;
- /* Advance PC across any function entry prologue instructions
- to reach some "real" code. */
- static CORE_ADDR
- vax_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
- {
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- gdb_byte op = read_memory_unsigned_integer (pc, 1, byte_order);
- if (op == 0x11)
- pc += 2; /* skip brb */
- if (op == 0x31)
- pc += 3; /* skip brw */
- if (op == 0xC2
- && read_memory_unsigned_integer (pc + 2, 1, byte_order) == 0x5E)
- pc += 3; /* skip subl2 */
- if (op == 0x9E
- && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xAE
- && read_memory_unsigned_integer (pc + 3, 1, byte_order) == 0x5E)
- pc += 4; /* skip movab */
- if (op == 0x9E
- && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xCE
- && read_memory_unsigned_integer (pc + 4, 1, byte_order) == 0x5E)
- pc += 5; /* skip movab */
- if (op == 0x9E
- && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xEE
- && read_memory_unsigned_integer (pc + 6, 1, byte_order) == 0x5E)
- pc += 7; /* skip movab */
- return pc;
- }
- /* Unwinding the stack is relatively easy since the VAX has a
- dedicated frame pointer, and frames are set up automatically as the
- result of a function call. Most of the relevant information can be
- inferred from the documentation of the Procedure Call Instructions
- in the VAX MACRO and Instruction Set Reference Manual. */
- struct vax_frame_cache
- {
- /* Base address. */
- CORE_ADDR base;
- /* Table of saved registers. */
- trad_frame_saved_reg *saved_regs;
- };
- static struct vax_frame_cache *
- vax_frame_cache (struct frame_info *this_frame, void **this_cache)
- {
- struct vax_frame_cache *cache;
- CORE_ADDR addr;
- ULONGEST mask;
- int regnum;
- if (*this_cache)
- return (struct vax_frame_cache *) *this_cache;
- /* Allocate a new cache. */
- cache = FRAME_OBSTACK_ZALLOC (struct vax_frame_cache);
- cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
- /* The frame pointer is used as the base for the frame. */
- cache->base = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM);
- if (cache->base == 0)
- return cache;
- /* The register save mask and control bits determine the layout of
- the stack frame. */
- mask = get_frame_memory_unsigned (this_frame, cache->base + 4, 4) >> 16;
- /* These are always saved. */
- cache->saved_regs[VAX_PC_REGNUM].set_addr (cache->base + 16);
- cache->saved_regs[VAX_FP_REGNUM].set_addr (cache->base + 12);
- cache->saved_regs[VAX_AP_REGNUM].set_addr (cache->base + 8);
- cache->saved_regs[VAX_PS_REGNUM].set_addr (cache->base + 4);
- /* Scan the register save mask and record the location of the saved
- registers. */
- addr = cache->base + 20;
- for (regnum = 0; regnum < VAX_AP_REGNUM; regnum++)
- {
- if (mask & (1 << regnum))
- {
- cache->saved_regs[regnum].set_addr (addr);
- addr += 4;
- }
- }
- /* The CALLS/CALLG flag determines whether this frame has a General
- Argument List or a Stack Argument List. */
- if (mask & (1 << 13))
- {
- ULONGEST numarg;
- /* This is a procedure with Stack Argument List. Adjust the
- stack address for the arguments that were pushed onto the
- stack. The return instruction will automatically pop the
- arguments from the stack. */
- numarg = get_frame_memory_unsigned (this_frame, addr, 1);
- addr += 4 + numarg * 4;
- }
- /* Bits 1:0 of the stack pointer were saved in the control bits. */
- cache->saved_regs[VAX_SP_REGNUM].set_value (addr + (mask >> 14));
- return cache;
- }
- static void
- vax_frame_this_id (struct frame_info *this_frame, void **this_cache,
- struct frame_id *this_id)
- {
- struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache);
- /* This marks the outermost frame. */
- if (cache->base == 0)
- return;
- (*this_id) = frame_id_build (cache->base, get_frame_func (this_frame));
- }
- static struct value *
- vax_frame_prev_register (struct frame_info *this_frame,
- void **this_cache, int regnum)
- {
- struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache);
- return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
- }
- static const struct frame_unwind vax_frame_unwind =
- {
- "vax prologue",
- NORMAL_FRAME,
- default_frame_unwind_stop_reason,
- vax_frame_this_id,
- vax_frame_prev_register,
- NULL,
- default_frame_sniffer
- };
- static CORE_ADDR
- vax_frame_base_address (struct frame_info *this_frame, void **this_cache)
- {
- struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache);
- return cache->base;
- }
- static CORE_ADDR
- vax_frame_args_address (struct frame_info *this_frame, void **this_cache)
- {
- return get_frame_register_unsigned (this_frame, VAX_AP_REGNUM);
- }
- static const struct frame_base vax_frame_base =
- {
- &vax_frame_unwind,
- vax_frame_base_address,
- vax_frame_base_address,
- vax_frame_args_address
- };
- /* Return number of arguments for FRAME. */
- static int
- vax_frame_num_args (struct frame_info *frame)
- {
- CORE_ADDR args;
- /* Assume that the argument pointer for the outermost frame is
- hosed, as is the case on NetBSD/vax ELF. */
- if (get_frame_base_address (frame) == 0)
- return 0;
- args = get_frame_register_unsigned (frame, VAX_AP_REGNUM);
- return get_frame_memory_unsigned (frame, args, 1);
- }
- /* Initialize the current architecture based on INFO. If possible, re-use an
- architecture from ARCHES, which is a list of architectures already created
- during this debugging session.
- Called e.g. at program startup, when reading a core file, and when reading
- a binary file. */
- static struct gdbarch *
- vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
- {
- struct gdbarch *gdbarch;
- /* If there is already a candidate, use it. */
- arches = gdbarch_list_lookup_by_info (arches, &info);
- if (arches != NULL)
- return arches->gdbarch;
- gdbarch = gdbarch_alloc (&info, NULL);
- set_gdbarch_float_format (gdbarch, floatformats_vax_f);
- set_gdbarch_double_format (gdbarch, floatformats_vax_d);
- set_gdbarch_long_double_format (gdbarch, floatformats_vax_d);
- set_gdbarch_long_double_bit (gdbarch, 64);
- /* Register info */
- set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS);
- set_gdbarch_register_name (gdbarch, vax_register_name);
- set_gdbarch_register_type (gdbarch, vax_register_type);
- set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM);
- set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM);
- set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM);
- set_gdbarch_iterate_over_regset_sections
- (gdbarch, vax_iterate_over_regset_sections);
- /* Frame and stack info */
- set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue);
- set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args);
- set_gdbarch_frame_args_skip (gdbarch, 4);
- /* Stack grows downward. */
- set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
- /* Return value info */
- set_gdbarch_return_value (gdbarch, vax_return_value);
- /* Call dummy code. */
- set_gdbarch_push_dummy_call (gdbarch, vax_push_dummy_call);
- set_gdbarch_dummy_id (gdbarch, vax_dummy_id);
- /* Breakpoint info */
- set_gdbarch_breakpoint_kind_from_pc (gdbarch, vax_breakpoint::kind_from_pc);
- set_gdbarch_sw_breakpoint_from_kind (gdbarch, vax_breakpoint::bp_from_kind);
- /* Misc info */
- set_gdbarch_deprecated_function_start_offset (gdbarch, 2);
- set_gdbarch_believe_pcc_promotion (gdbarch, 1);
- frame_base_set_default (gdbarch, &vax_frame_base);
- /* Hook in ABI-specific overrides, if they have been registered. */
- gdbarch_init_osabi (info, gdbarch);
- frame_unwind_append_unwinder (gdbarch, &vax_frame_unwind);
- return (gdbarch);
- }
- void _initialize_vax_tdep ();
- void
- _initialize_vax_tdep ()
- {
- gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL);
- }
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