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- /* Copyright (C) 2012-2022 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 "osabi.h"
- #include "regcache.h"
- #include "gdbcore.h"
- #include "gdbtypes.h"
- #include "infcall.h"
- #include "ppc-tdep.h"
- #include "target-float.h"
- #include "value.h"
- #include "xcoffread.h"
- /* Implement the "push_dummy_call" gdbarch method. */
- static CORE_ADDR
- rs6000_lynx178_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)
- {
- ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- int ii;
- int len = 0;
- int argno; /* current argument number */
- int argbytes; /* current argument byte */
- gdb_byte tmp_buffer[50];
- int f_argno = 0; /* current floating point argno */
- int wordsize = tdep->wordsize;
- struct value *arg = 0;
- struct type *type;
- ULONGEST saved_sp;
- /* The calling convention this function implements assumes the
- processor has floating-point registers. We shouldn't be using it
- on PPC variants that lack them. */
- gdb_assert (ppc_floating_point_unit_p (gdbarch));
- /* The first eight words of ther arguments are passed in registers.
- Copy them appropriately. */
- ii = 0;
- /* If the function is returning a `struct', then the first word
- (which will be passed in r3) is used for struct return address.
- In that case we should advance one word and start from r4
- register to copy parameters. */
- if (return_method == return_method_struct)
- {
- regcache_raw_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
- struct_addr);
- ii++;
- }
- /* Effectively indirect call... gcc does...
- return_val example( float, int);
- eabi:
- float in fp0, int in r3
- offset of stack on overflow 8/16
- for varargs, must go by type.
- power open:
- float in r3&r4, int in r5
- offset of stack on overflow different
- both:
- return in r3 or f0. If no float, must study how gcc emulates floats;
- pay attention to arg promotion.
- User may have to cast\args to handle promotion correctly
- since gdb won't know if prototype supplied or not. */
- for (argno = 0, argbytes = 0; argno < nargs && ii < 8; ++ii)
- {
- int reg_size = register_size (gdbarch, ii + 3);
- arg = args[argno];
- type = check_typedef (value_type (arg));
- len = TYPE_LENGTH (type);
- if (type->code () == TYPE_CODE_FLT)
- {
- /* Floating point arguments are passed in fpr's, as well as gpr's.
- There are 13 fpr's reserved for passing parameters. At this point
- there is no way we would run out of them.
- Always store the floating point value using the register's
- floating-point format. */
- const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
- gdb_byte reg_val[PPC_MAX_REGISTER_SIZE];
- struct type *reg_type = register_type (gdbarch, fp_regnum);
- gdb_assert (len <= 8);
- target_float_convert (value_contents (arg).data (), type, reg_val,
- reg_type);
- regcache->cooked_write (fp_regnum, reg_val);
- ++f_argno;
- }
- if (len > reg_size)
- {
- /* Argument takes more than one register. */
- while (argbytes < len)
- {
- gdb_byte word[PPC_MAX_REGISTER_SIZE];
- memset (word, 0, reg_size);
- memcpy (word,
- ((char *) value_contents (arg).data ()) + argbytes,
- (len - argbytes) > reg_size
- ? reg_size : len - argbytes);
- regcache->cooked_write (tdep->ppc_gp0_regnum + 3 + ii, word);
- ++ii, argbytes += reg_size;
- if (ii >= 8)
- goto ran_out_of_registers_for_arguments;
- }
- argbytes = 0;
- --ii;
- }
- else
- {
- /* Argument can fit in one register. No problem. */
- gdb_byte word[PPC_MAX_REGISTER_SIZE];
- memset (word, 0, reg_size);
- memcpy (word, value_contents (arg).data (), len);
- regcache->cooked_write (tdep->ppc_gp0_regnum + 3 +ii, word);
- }
- ++argno;
- }
- ran_out_of_registers_for_arguments:
- regcache_cooked_read_unsigned (regcache,
- gdbarch_sp_regnum (gdbarch),
- &saved_sp);
- /* Location for 8 parameters are always reserved. */
- sp -= wordsize * 8;
- /* Another six words for back chain, TOC register, link register, etc. */
- sp -= wordsize * 6;
- /* Stack pointer must be quadword aligned. */
- sp = align_down (sp, 16);
- /* If there are more arguments, allocate space for them in
- the stack, then push them starting from the ninth one. */
- if ((argno < nargs) || argbytes)
- {
- int space = 0, jj;
- if (argbytes)
- {
- space += align_up (len - argbytes, 4);
- jj = argno + 1;
- }
- else
- jj = argno;
- for (; jj < nargs; ++jj)
- {
- struct value *val = args[jj];
- space += align_up (TYPE_LENGTH (value_type (val)), 4);
- }
- /* Add location required for the rest of the parameters. */
- space = align_up (space, 16);
- sp -= space;
- /* This is another instance we need to be concerned about
- securing our stack space. If we write anything underneath %sp
- (r1), we might conflict with the kernel who thinks he is free
- to use this area. So, update %sp first before doing anything
- else. */
- regcache_raw_write_signed (regcache,
- gdbarch_sp_regnum (gdbarch), sp);
- /* If the last argument copied into the registers didn't fit there
- completely, push the rest of it into stack. */
- if (argbytes)
- {
- write_memory (sp + 24 + (ii * 4),
- value_contents (arg).data () + argbytes,
- len - argbytes);
- ++argno;
- ii += align_up (len - argbytes, 4) / 4;
- }
- /* Push the rest of the arguments into stack. */
- for (; argno < nargs; ++argno)
- {
- arg = args[argno];
- type = check_typedef (value_type (arg));
- len = TYPE_LENGTH (type);
- /* Float types should be passed in fpr's, as well as in the
- stack. */
- if (type->code () == TYPE_CODE_FLT && f_argno < 13)
- {
- gdb_assert (len <= 8);
- regcache->cooked_write (tdep->ppc_fp0_regnum + 1 + f_argno,
- value_contents (arg).data ());
- ++f_argno;
- }
- write_memory (sp + 24 + (ii * 4), value_contents (arg).data (), len);
- ii += align_up (len, 4) / 4;
- }
- }
- /* Set the stack pointer. According to the ABI, the SP is meant to
- be set _before_ the corresponding stack space is used. On AIX,
- this even applies when the target has been completely stopped!
- Not doing this can lead to conflicts with the kernel which thinks
- that it still has control over this not-yet-allocated stack
- region. */
- regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp);
- /* Set back chain properly. */
- store_unsigned_integer (tmp_buffer, wordsize, byte_order, saved_sp);
- write_memory (sp, tmp_buffer, wordsize);
- /* Point the inferior function call's return address at the dummy's
- breakpoint. */
- regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);
- target_store_registers (regcache, -1);
- return sp;
- }
- /* Implement the "return_value" gdbarch method. */
- static enum return_value_convention
- rs6000_lynx178_return_value (struct gdbarch *gdbarch, struct value *function,
- struct type *valtype, struct regcache *regcache,
- gdb_byte *readbuf, const gdb_byte *writebuf)
- {
- ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- /* The calling convention this function implements assumes the
- processor has floating-point registers. We shouldn't be using it
- on PowerPC variants that lack them. */
- gdb_assert (ppc_floating_point_unit_p (gdbarch));
- /* AltiVec extension: Functions that declare a vector data type as a
- return value place that return value in VR2. */
- if (valtype->code () == TYPE_CODE_ARRAY && valtype->is_vector ()
- && TYPE_LENGTH (valtype) == 16)
- {
- if (readbuf)
- regcache->cooked_read (tdep->ppc_vr0_regnum + 2, readbuf);
- if (writebuf)
- regcache->cooked_write (tdep->ppc_vr0_regnum + 2, writebuf);
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
- /* If the called subprogram returns an aggregate, there exists an
- implicit first argument, whose value is the address of a caller-
- allocated buffer into which the callee is assumed to store its
- return value. All explicit parameters are appropriately
- relabeled. */
- if (valtype->code () == TYPE_CODE_STRUCT
- || valtype->code () == TYPE_CODE_UNION
- || valtype->code () == TYPE_CODE_ARRAY)
- return RETURN_VALUE_STRUCT_CONVENTION;
- /* Scalar floating-point values are returned in FPR1 for float or
- double, and in FPR1:FPR2 for quadword precision. Fortran
- complex*8 and complex*16 are returned in FPR1:FPR2, and
- complex*32 is returned in FPR1:FPR4. */
- if (valtype->code () == TYPE_CODE_FLT
- && (TYPE_LENGTH (valtype) == 4 || TYPE_LENGTH (valtype) == 8))
- {
- struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
- gdb_byte regval[8];
- /* FIXME: kettenis/2007-01-01: Add support for quadword
- precision and complex. */
- if (readbuf)
- {
- regcache->cooked_read (tdep->ppc_fp0_regnum + 1, regval);
- target_float_convert (regval, regtype, readbuf, valtype);
- }
- if (writebuf)
- {
- target_float_convert (writebuf, valtype, regval, regtype);
- regcache->cooked_write (tdep->ppc_fp0_regnum + 1, regval);
- }
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
- /* Values of the types int, long, short, pointer, and char (length
- is less than or equal to four bytes), as well as bit values of
- lengths less than or equal to 32 bits, must be returned right
- justified in GPR3 with signed values sign extended and unsigned
- values zero extended, as necessary. */
- if (TYPE_LENGTH (valtype) <= tdep->wordsize)
- {
- if (readbuf)
- {
- ULONGEST regval;
- /* For reading we don't have to worry about sign extension. */
- regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
- ®val);
- store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), byte_order,
- regval);
- }
- if (writebuf)
- {
- /* For writing, use unpack_long since that should handle any
- required sign extension. */
- regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
- unpack_long (valtype, writebuf));
- }
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
- /* Eight-byte non-floating-point scalar values must be returned in
- GPR3:GPR4. */
- if (TYPE_LENGTH (valtype) == 8)
- {
- gdb_assert (valtype->code () != TYPE_CODE_FLT);
- gdb_assert (tdep->wordsize == 4);
- if (readbuf)
- {
- gdb_byte regval[8];
- regcache->cooked_read (tdep->ppc_gp0_regnum + 3, regval);
- regcache->cooked_read (tdep->ppc_gp0_regnum + 4, regval + 4);
- memcpy (readbuf, regval, 8);
- }
- if (writebuf)
- {
- regcache->cooked_write (tdep->ppc_gp0_regnum + 3, writebuf);
- regcache->cooked_write (tdep->ppc_gp0_regnum + 4, writebuf + 4);
- }
- return RETURN_VALUE_REGISTER_CONVENTION;
- }
- return RETURN_VALUE_STRUCT_CONVENTION;
- }
- /* PowerPC Lynx178 OSABI sniffer. */
- static enum gdb_osabi
- rs6000_lynx178_osabi_sniffer (bfd *abfd)
- {
- if (bfd_get_flavour (abfd) != bfd_target_xcoff_flavour)
- return GDB_OSABI_UNKNOWN;
- /* The only noticeable difference between Lynx178 XCOFF files and
- AIX XCOFF files comes from the fact that there are no shared
- libraries on Lynx178. So if the number of import files is
- different from zero, it cannot be a Lynx178 binary. */
- if (xcoff_get_n_import_files (abfd) != 0)
- return GDB_OSABI_UNKNOWN;
- return GDB_OSABI_LYNXOS178;
- }
- /* Callback for powerpc-lynx178 initialization. */
- static void
- rs6000_lynx178_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
- {
- set_gdbarch_push_dummy_call (gdbarch, rs6000_lynx178_push_dummy_call);
- set_gdbarch_return_value (gdbarch, rs6000_lynx178_return_value);
- set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
- }
- void _initialize_rs6000_lynx178_tdep ();
- void
- _initialize_rs6000_lynx178_tdep ()
- {
- gdbarch_register_osabi_sniffer (bfd_arch_rs6000,
- bfd_target_xcoff_flavour,
- rs6000_lynx178_osabi_sniffer);
- gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_LYNXOS178,
- rs6000_lynx178_init_osabi);
- }
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