Annotation of gcc/expr.h, revision 1.1.1.9

1.1       root        1: /* Definitions for code generation pass of GNU compiler.
                      2:    Copyright (C) 1987 Free Software Foundation, Inc.
                      3: 
                      4: This file is part of GNU CC.
                      5: 
1.1.1.8   root        6: GNU CC is free software; you can redistribute it and/or modify
                      7: it under the terms of the GNU General Public License as published by
                      8: the Free Software Foundation; either version 1, or (at your option)
                      9: any later version.
                     10: 
1.1       root       11: GNU CC is distributed in the hope that it will be useful,
1.1.1.8   root       12: but WITHOUT ANY WARRANTY; without even the implied warranty of
                     13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     14: GNU General Public License for more details.
                     15: 
                     16: You should have received a copy of the GNU General Public License
                     17: along with GNU CC; see the file COPYING.  If not, write to
                     18: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
1.1       root       19: 
                     20: 
                     21: /* Macros to access the slots of a QUEUED rtx.
                     22:    Here rather than in rtl.h because only the expansion pass
                     23:    should ever encounter a QUEUED.  */
                     24: 
                     25: /* The variable for which an increment is queued.  */
1.1.1.2   root       26: #define QUEUED_VAR(P) XEXP (P, 0)
1.1       root       27: /* If the increment has been emitted, this is the insn
                     28:    that does the increment.  It is zero before the increment is emitted.  */
1.1.1.2   root       29: #define QUEUED_INSN(P) XEXP (P, 1)
1.1       root       30: /* If a pre-increment copy has been generated, this is the copy
                     31:    (it is a temporary reg).  Zero if no copy made yet.  */
1.1.1.2   root       32: #define QUEUED_COPY(P) XEXP (P, 2)
1.1       root       33: /* This is the body to use for the insn to do the increment.
                     34:    It is used to emit the increment.  */
1.1.1.2   root       35: #define QUEUED_BODY(P) XEXP (P, 3)
1.1       root       36: /* Next QUEUED in the queue.  */
1.1.1.2   root       37: #define QUEUED_NEXT(P) XEXP (P, 4)
                     38: 
                     39: /* This is the 4th arg to `expand_expr'.
                     40:    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
                     41:    EXPND_CONST_ADDRESS means it is ok to return a MEM whose address
                     42:     is a constant that is not a legitimate address.  */
                     43: enum expand_modifier {EXPAND_NORMAL, EXPAND_SUM, EXPAND_CONST_ADDRESS};
1.1       root       44: 
                     45: /* If this is nonzero, we do not bother generating VOLATILE
                     46:    around volatile memory references, and we are willing to
                     47:    output indirect addresses.  If cse is to follow, we reject
                     48:    indirect addresses so a useful potential cse is generated;
                     49:    if it is used only once, instruction combination will produce
                     50:    the same indirect address eventually.  */
                     51: extern int cse_not_expected;
                     52: 
1.1.1.4   root       53: /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
                     54:    So we can mark them all live at the end of the function, if stupid.  */
                     55: extern rtx save_expr_regs;
1.1.1.5   root       56: 
1.1.1.2   root       57: #ifdef TREE_CODE /* Don't lose if tree.h not included.  */
                     58: /* Structure to record the size of a sequence of arguments
                     59:    as the sum of a tree-expression and a constant.  */
                     60: 
                     61: struct args_size
                     62: {
                     63:   int constant;
                     64:   tree var;
                     65: };
                     66: #endif
                     67: 
                     68: /* Add the value of the tree INC to the `struct args_size' TO.  */
                     69: 
                     70: #define ADD_PARM_SIZE(TO, INC) \
                     71: { tree inc = (INC);                            \
                     72:   if (TREE_CODE (inc) == INTEGER_CST)          \
                     73:     (TO).constant += TREE_INT_CST_LOW (inc);   \
                     74:   else if ((TO).var == 0)                      \
                     75:     (TO).var = inc;                            \
                     76:   else                                         \
                     77:     (TO).var = genop (PLUS_EXPR, (TO).var, inc); }
                     78: 
1.1.1.5   root       79: #define SUB_PARM_SIZE(TO, DEC) \
                     80: { tree dec = (DEC);                            \
                     81:   if (TREE_CODE (dec) == INTEGER_CST)          \
                     82:     (TO).constant -= TREE_INT_CST_LOW (dec);   \
                     83:   else if ((TO).var == 0)                      \
                     84:     (TO).var = genop (MINUS_EXPR, integer_zero_node, dec); \
                     85:   else                                         \
                     86:     (TO).var = genop (MINUS_EXPR, (TO).var, dec); }
                     87: 
1.1.1.2   root       88: /* Convert the implicit sum in a `struct args_size' into an rtx.  */
                     89: #define ARGS_SIZE_RTX(SIZE)                                            \
                     90: ((SIZE).var == 0 ? gen_rtx (CONST_INT, VOIDmode, (SIZE).constant)      \
                     91:  : plus_constant (expand_expr ((SIZE).var, 0, VOIDmode, 0),            \
                     92:                  (SIZE).constant))
1.1.1.5   root       93: 
                     94: /* Supply a default definition for FUNCTION_ARG_PADDING:
                     95:    usually pad upward, but pad short args downward on big-endian machines.  */
                     96: 
                     97: enum direction {none, upward, downward};  /* Value has this type.  */
                     98: 
                     99: #ifndef FUNCTION_ARG_PADDING
                    100: #ifdef BYTES_BIG_ENDIAN
                    101: #define FUNCTION_ARG_PADDING(mode, size)                               \
                    102:   (((mode) == BLKmode                                                  \
                    103:     ? (GET_CODE (size) == CONST_INT                                    \
                    104:        && INTVAL (size) < PARM_BOUNDARY / BITS_PER_UNIT)               \
                    105:     : GET_MODE_BITSIZE (mode) < PARM_BOUNDARY)                         \
                    106:    ? downward : upward)
                    107: #else
                    108: #define FUNCTION_ARG_PADDING(mode, size) upward
                    109: #endif
                    110: #endif
1.1.1.9 ! root      111: 
        !           112: /* Nonzero if type TYPE should be returned in memory
        !           113:    (even though its mode is not BLKmode).
        !           114:    Most machines can use the following default definition.  */
        !           115: 
        !           116: #ifndef RETURN_IN_MEMORY
        !           117: #define RETURN_IN_MEMORY(type) 0
        !           118: #endif
1.1.1.2   root      119: 
1.1       root      120: /* Optabs are tables saying how to generate insn bodies
                    121:    for various machine modes and numbers of operands.
                    122:    Each optab applies to one operation.
                    123:    For example, add_optab applies to addition.
                    124: 
                    125:    The insn_code slot is the enum insn_code that says how to
                    126:    generate an insn for this operation on a particular machine mode.
                    127:    It is CODE_FOR_nothing if there is no such insn on the target machine.
                    128: 
                    129:    The `lib_call' slot is the name of the library function that
                    130:    can be used to perform the operation.
                    131: 
                    132:    A few optabs, such as move_optab and cmp_optab, are used
                    133:    by special code.  */
                    134: 
                    135: /* Everything that uses expr.h needs to define enum insn_code
                    136:    but we don't list it in the Makefile dependencies just for that.  */
                    137: #include "insn-codes.h"
                    138: 
                    139: typedef struct optab
                    140: {
1.1.1.2   root      141:   enum rtx_code code;
                    142:   struct {
                    143:     enum insn_code insn_code;
                    144:     char *lib_call;
                    145:   } handlers [NUM_MACHINE_MODES];
                    146: } * optab;
1.1       root      147: 
                    148: /* Given an enum insn_code, access the function to construct
                    149:    the body of that kind of insn.  */
                    150: #define GEN_FCN(CODE) (*insn_gen_function[(int) (CODE)])
                    151: extern rtx (*insn_gen_function[]) ();
                    152: 
                    153: extern optab add_optab;
                    154: extern optab sub_optab;
                    155: extern optab smul_optab;       /* Signed multiply */
                    156: extern optab umul_optab;       /* Unsigned multiply */
                    157: extern optab smul_widen_optab; /* Signed multiply with result 
                    158:                                   one machine mode wider than args */
                    159: extern optab umul_widen_optab;
                    160: extern optab sdiv_optab;       /* Signed divide */
                    161: extern optab sdivmod_optab;    /* Signed divide-and-remainder in one */
                    162: extern optab udiv_optab;
                    163: extern optab udivmod_optab;
                    164: extern optab smod_optab;       /* Signed remainder */
                    165: extern optab umod_optab;
                    166: extern optab flodiv_optab;     /* Optab for floating divide. */
1.1.1.2   root      167: extern optab ftrunc_optab;     /* Convert float to integer in float fmt */
1.1       root      168: extern optab and_optab;                /* Logical and */
                    169: extern optab andcb_optab;      /* Logical and with complement of 2nd arg */
                    170: extern optab ior_optab;                /* Logical or */
                    171: extern optab xor_optab;                /* Logical xor */
                    172: extern optab ashl_optab;       /* Arithmetic shift left */
                    173: extern optab ashr_optab;       /* Arithmetic shift right */
                    174: extern optab lshl_optab;       /* Logical shift left */
                    175: extern optab lshr_optab;       /* Logical shift right */
                    176: extern optab rotl_optab;       /* Rotate left */
                    177: extern optab rotr_optab;       /* Rotate right */
                    178: 
                    179: extern optab mov_optab;                /* Move instruction.  */
                    180: extern optab movstrict_optab;  /* Move, preserving high part of register.  */
                    181: 
                    182: extern optab cmp_optab;                /* Compare insn; two operands.  */
                    183: extern optab tst_optab;                /* tst insn; compare one operand against 0 */
                    184: 
                    185: /* Unary operations */
                    186: extern optab neg_optab;                /* Negation */
                    187: extern optab abs_optab;                /* Abs value */
                    188: extern optab one_cmpl_optab;   /* Bitwise not */
1.1.1.2   root      189: extern optab ffs_optab;                /* Find first bit set */
1.1       root      190: 
                    191: /* Passed to expand_binop and expand_unop to say which options to try to use
                    192:    if the requested operation can't be open-coded on the requisite mode.
                    193:    Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using a library call.
                    194:    Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try using a wider mode.  */
                    195: 
                    196: enum optab_methods
                    197: {
                    198:   OPTAB_DIRECT,
                    199:   OPTAB_LIB,
                    200:   OPTAB_WIDEN,
                    201:   OPTAB_LIB_WIDEN,
                    202: };
                    203: 
                    204: typedef rtx (*rtxfun) ();
                    205: 
1.1.1.7   root      206: /* Indexed by the rtx-code for a conditional (eg. EQ, LT,...)
                    207:    gives the gen_function to make a branch to test that condition.  */
                    208: 
                    209: extern rtxfun bcc_gen_fctn[NUM_RTX_CODE];
                    210: 
                    211: /* Indexed by the rtx-code for a conditional (eg. EQ, LT,...)
                    212:    gives the gen_function to make a store-condition insn
                    213:    to test that condition.  */
                    214: 
                    215: extern rtxfun setcc_gen_fctn[NUM_RTX_CODE];
                    216: 
1.1       root      217: /* Expand a binary operation given optab and rtx operands.  */
                    218: rtx expand_binop ();
                    219: 
1.1.1.8   root      220: /* Expand a binary operation with both signed and unsigned forms.  */
                    221: rtx sign_expand_binop ();
                    222: 
1.1       root      223: /* Expand a unary arithmetic operation given optab rtx operand.  */
                    224: rtx expand_unop ();
                    225: 
1.1.1.6   root      226: /* Arguments MODE, RTX: return an rtx for the negation of that value.
                    227:    May emit insns.  */
                    228: rtx negate_rtx ();
                    229: 
1.1       root      230: /* Initialize the tables that control conversion between fixed and
                    231:    floating values.  */
                    232: void init_fixtab ();
                    233: void init_floattab ();
                    234: 
                    235: /* Generate code for a FIX_EXPR.  */
                    236: void expand_fix ();
                    237: 
                    238: /* Generate code for a FLOAT_EXPR.  */
                    239: void expand_float ();
                    240: 
                    241: /* Create but don't emit one rtl instruction to add one rtx into another.
                    242:    Modes must match.
                    243:    Likewise for subtraction and for just copying.
                    244:    These do not call protect_from_queue; caller must do so.  */
                    245: rtx gen_add2_insn ();
                    246: rtx gen_sub2_insn ();
                    247: rtx gen_move_insn ();
                    248: 
                    249: /* Emit one rtl instruction to store zero in specified rtx.  */
                    250: void emit_clr_insn ();
                    251: 
                    252: /* Emit one rtl insn to store 1 in specified rtx assuming it contains 0.  */
                    253: void emit_0_to_1_insn ();
                    254: 
                    255: /* Emit one rtl insn to compare two rtx's.  */
                    256: void emit_cmp_insn ();
                    257: 
                    258: /* Emit some rtl insns to move data between rtx's, converting machine modes.
                    259:    Both modes must be floating or both fixed.  */
                    260: void convert_move ();
                    261: 
                    262: /* Convert an rtx to specified machine mode and return the result.  */
                    263: rtx convert_to_mode ();
                    264: 
                    265: /* Emit code to push some arguments and call a library routine,
                    266:    storing the value in a specified place.  Calling sequence is
                    267:    complicated.  */
                    268: void emit_library_call ();
                    269: 
                    270: /* Given an rtx that may include add and multiply operations,
                    271:    generate them as insns and return a pseudo-reg containing the value.
                    272:    Useful after calling expand_expr with 1 as sum_ok.  */
                    273: rtx force_operand ();
                    274: 
                    275: /* Return an rtx for the size in bytes of the value of an expr.  */
                    276: rtx expr_size ();
                    277: 
                    278: /* Return an rtx for the sum of an rtx and an integer.  */
                    279: rtx plus_constant ();
                    280: 
                    281: rtx lookup_static_chain ();
                    282: 
                    283: /* Return an rtx like arg but sans any constant terms.
                    284:    Returns the original rtx if it has no constant terms.
                    285:    The constant terms are added and stored via a second arg.  */
                    286: rtx eliminate_constant_term ();
                    287: 
                    288: /* Convert arg to a valid memory address for specified machine mode,
                    289:    by emitting insns to perform arithmetic if nec.  */
                    290: rtx memory_address ();
                    291: 
1.1.1.3   root      292: /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
                    293: rtx memory_address_noforce ();
                    294: 
1.1.1.2   root      295: /* Return a memory reference like MEMREF, but with its mode changed
                    296:    to MODE and its address changed to ADDR.
                    297:    (VOIDmode means don't change the mode.
                    298:    NULL for ADDR means don't change the address.)  */
                    299: rtx change_address ();
1.1       root      300: 
                    301: /* Return 1 if two rtx's are equivalent in structure and elements.  */
                    302: int rtx_equal_p ();
                    303: 
                    304: /* Given rtx, return new rtx whose address won't be affected by
                    305:    any side effects.  It has been copied to a new temporary reg.  */
                    306: rtx stabilize ();
                    307: 
                    308: /* Given an rtx, copy all regs it refers to into new temps
                    309:    and return a modified copy that refers to the new temps.  */
                    310: rtx copy_all_regs ();
                    311: 
                    312: /* Copy given rtx to a new temp reg and return that.  */
                    313: rtx copy_to_reg ();
                    314: 
1.1.1.2   root      315: /* Like copy_to_reg but always make the reg Pmode.  */
                    316: rtx copy_addr_to_reg ();
                    317: 
                    318: /* Like copy_to_reg but always make the reg the specified mode MODE.  */
                    319: rtx copy_to_mode_reg ();
                    320: 
1.1       root      321: /* Copy given rtx to given temp reg and return that.  */
                    322: rtx copy_to_suggested_reg ();
                    323: 
1.1.1.2   root      324: /* Copy a value to a register if it isn't already a register.
                    325:    Args are mode (in case value is a constant) and the value.  */
                    326: rtx force_reg ();
                    327: 
1.1       root      328: /* Return given rtx, copied into a new temp reg if it was in memory.  */
                    329: rtx force_not_mem ();
                    330: 
                    331: /* Remove some bytes from the stack.  An rtx says how many.  */
                    332: void adjust_stack ();
                    333: 
                    334: /* Add some bytes to the stack.  An rtx says how many.  */
                    335: void anti_adjust_stack ();
                    336: 
                    337: /* Emit code to copy function value to a new temp reg and return that reg.  */
                    338: rtx function_value ();
                    339: 
                    340: /* Return an rtx that refers to the value returned by a function
                    341:    in its original home.  This becomes invalid if any more code is emitted.  */
                    342: rtx hard_function_value ();
                    343: 
1.1.1.2   root      344: /* Return an rtx that refers to the value returned by a library call
                    345:    in its original home.  This becomes invalid if any more code is emitted.  */
                    346: rtx hard_libcall_value ();
                    347: 
1.1       root      348: /* Emit code to copy function value to a specified place.  */
                    349: void copy_function_value ();
                    350: 
1.1.1.2   root      351: /* Given an rtx, return an rtx for a value rounded up to a multiple
                    352:    of STACK_BOUNDARY / BITS_PER_UNIT.  */
                    353: rtx round_push ();
                    354: 
1.1       root      355: rtx store_bit_field ();
                    356: rtx extract_bit_field ();
                    357: rtx expand_shift ();
                    358: rtx expand_bit_and ();
                    359: rtx expand_mult ();
                    360: rtx expand_divmod ();
                    361: rtx get_structure_value_addr ();
1.1.1.2   root      362: rtx expand_stmt_expr ();
                    363: 
                    364: void jumpifnot ();
                    365: void jumpif ();
                    366: void do_jump ();
1.1.1.8   root      367: 
                    368: rtx assemble_static_space ();

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