gen.h

   1 /* neatcc code generation interface */
   2 /* basic types */
   3 #define BT_SZMASK       0x00ff
   4 #define BT_SIGNED       0x0100
   5 #define BT_SZ(bt)       ((bt) & BT_SZMASK)
   6
   7 #define O_SIGNED        0x100
   8 /* binary instructions for o_bop() */
   9 #define O_ADD           0x00
  10 #define O_SUB           0x01
  11 #define O_AND           0x02
  12 #define O_OR            0x03
  13 #define O_XOR           0x04
  14 #define O_SHL           0x10
  15 #define O_SHR           0x11
  16 #define O_MUL           0x20
  17 #define O_DIV           0x21
  18 #define O_MOD           0x22
  19 #define O_LT            0x30
  20 #define O_GT            0x31
  21 #define O_LE            0x32
  22 #define O_GE            0x33
  23 #define O_EQ            0x34
  24 #define O_NEQ           0x35
  25 /* unary instructions for o_uop() */
  26 #define O_NEG           0x40
  27 #define O_NOT           0x41
  28 #define O_LNOT          0x42
  29
  30 /* operations on the stack */
  31 void o_bop(int op);             /* binary operation */
  32 void o_uop(int op);             /* unary operation */
  33 void o_cast(unsigned bt);
  34 void o_memcpy(void);
  35 void o_memset(void);
  36 void o_call(int argc, int ret);
  37 void o_ret(int ret);
  38 void o_assign(unsigned bt);
  39 void o_deref(unsigned bt);
  40 void o_load(void);
  41 int o_popnum(long *c);
  42 /* pushing values to the stack */
  43 void o_num(long n);
  44 void o_local(long addr);
  45 void o_sym(char *sym);
  46 void o_tmpdrop(int n);
  47 void o_tmpswap(void);
  48 void o_tmpcopy(void);
  49 /* handling locals */
  50 long o_mklocal(int size);
  51 void o_rmlocal(long addr, int sz);
  52 long o_arg2loc(int i);
  53 /* branches */
  54 void o_label(int id);
  55 void o_jmp(int id);
  56 void o_jz(int id);
  57 void o_jnz(int id);
  58 /* conditional instructions */
  59 void o_fork(void);
  60 void o_forkpush(void);
  61 void o_forkjoin(void);
  62 /* data/bss sections */
  63 long o_dsnew(char *name, int size, int global);
  64 void o_dscpy(long addr, void *buf, int len);
  65 void o_dsset(char *name, int off, unsigned bt);
  66 void o_bsnew(char *name, int size, int global);
  67 /* functions */
  68 void o_func_beg(char *name, int argc, int global, int vararg);
  69 void o_func_end(void);
  70 /* output */
  71 void o_write(int fd);
  72 /* passes */
  73 void o_pass1(void);
  74 void o_pass2(void);
  75
  76 /*
  77  * neatcc architecture-dependent code-generation interface
  78  *
  79  * To make maintaining three different architectures easier and unifying the
  80  * optimization patch, I've extracted gen.c from x86.c and arm.c.  The i_*()
  81  * functions are now the low level architecture-specific code generation
  82  * entry points.  The differences between RISC and CISC architectures,
  83  * actually the annoying asymmetry in CISC architecture, made this interface
  84  * a bit more complex than it could have ideally been.  Nevertheless, the
  85  * benefits of extracting gen.c and the cleaner design, especially with the
  86  * presence of the optimization patch, is worth the added complexity.
  87  *
  88  * I tried to make the interface as small as possible.  I'll describe the
  89  * key functions and macros here.  Overall, there were many challenges for
  90  * extracting gen.c including:
  91  * + Different register sets; caller/callee saved and argument registers
  92  * + CISC-style instructions that work on limited registers and parameters
  93  * + Different instruction formats and immediate value limitations
  94  * + Producing epilog, prolog, and local variable addresses when optimizing
  95  *
  96  * Instructions:
  97  * + i_reg(): The mask of allowed registers for each operand of an instruction.
  98  *   If md is zero, we assume the destination register should be equal to the
  99  *   first register, as in CISC architectures.  m2 can be zero which means
 100  *   the instruction doesn't have three operands.  mt denotes the mask of
 101  *   registers that may lose their contents after the instruction.
 102  * + i_load(), i_save(), i_mov(), i_num(), i_sym(): The name is clear.
 103  * + i_imm(): Specifies if the given immediate can be encoded for the given
 104  *   instruction.
 105  * + i_jmp(), i_fill(): Branching instructions.  If rn >= 0, the branch is
 106  *   a conditional branch: jump only the register rn is zero (or nonzero if
 107  *   jc is nonzero).  nbytes specifies the number of bytes necessary for
 108  *   holding the jump distance; useful if the architecture supports short
 109  *   branching instructions.  i_fill() actually fills the jump at src in
 110  *   code segment.  It returns the amount of bytes jumped.
 111  * + i_args(): The offset of the first argument from the frame pointer.
 112  *   It is probably positive.
 113  * + i_args(): The offset of the first local from the frame pointer.
 114  *   It is probably negative
 115  * + tmpregs: Register that can be used for holding temporaries.
 116  * + argregs: Register for holding the first N_ARGS arguments.
 117  *
 118  * There are a few other macros defined in arch headers.  See x64.h as
 119  * an example.
 120  *
 121  */
 122 #ifdef NEATCC_ARM
 123 #include "arm.h"
 124 #endif
 125 #ifdef NEATCC_X64
 126 #include "x64.h"
 127 #endif
 128 #ifdef NEATCC_X86
 129 #include "x86.h"
 130 #endif
 131
 132 /* intermediate instructions */
 133 #define O_IMM           0x200   /* mask for immediate instructions */
 134 #define O_MSET          0x51    /* memset() */
 135 #define O_MCPY          0x52    /* memcpy() */
 136 #define O_MOV           0x53    /* mov */
 137 #define O_SX            0x54    /* sign extend */
 138 #define O_ZX            0x55    /* zero extend */
 139
 140 void i_load(int rd, int rn, int off, int bt);
 141 void i_save(int rd, int rn, int off, int bt);
 142 void i_mov(int rd, int rn);
 143 void i_reg(int op, int *md, int *m1, int *m2, int *mt);
 144 void i_op(int op, int rd, int r1, int r2);
 145 int i_imm(int op, long imm);
 146 void i_op_imm(int op, int rd, int r1, long n);
 147
 148 void i_num(int rd, long n);
 149 void i_sym(int rd, char *sym, int off);
 150
 151 void i_jmp(int rn, int jc, int nbytes);
 152 long i_fill(long src, long dst, int nbytes);
 153
 154 void i_call(char *sym, int off);
 155 void i_call_reg(int rd);
 156 void i_memset(int r0, int r1, int r2);
 157 void i_memcpy(int r0, int r1, int r2);
 158
 159 int i_args(void);       /* the address of the first arg relative to fp */
 160 int i_sp(void);         /* the address of the first local relative to fp */
 161
 162 void i_prolog(int argc, int varg, int sargs, int sregs, int initfp, int subsp);
 163 void i_epilog(int sp_max);
 164 void i_done(void);
 165
 166 extern int tmpregs[];
 167 extern int argregs[];
 168
 169 /* code segment text */
 170 extern char cs[];               /* code segment */
 171 extern int cslen;               /* code segment length */
 172 extern int pass1;               /* first pass */
 173
 174 void os(void *s, int n);
 175 void oi(long n, int l);