optimized bound checking

This commit is contained in:
bellard 2002-07-13 15:55:38 +00:00
parent 264dbcfed2
commit 17cbb388d3

21
tcc.c
View file

@ -286,6 +286,8 @@ struct TCCState {
char/short stored in integer registers) */ char/short stored in integer registers) */
#define VT_MUSTBOUND 0x0800 /* bound checking must be done before #define VT_MUSTBOUND 0x0800 /* bound checking must be done before
dereferencing value */ dereferencing value */
#define VT_BOUNDED 0x8000 /* value is bounded. The address of the
bounding function call point is in vc */
#define VT_LVAL_BYTE 0x1000 /* lvalue is a byte */ #define VT_LVAL_BYTE 0x1000 /* lvalue is a byte */
#define VT_LVAL_SHORT 0x2000 /* lvalue is a short */ #define VT_LVAL_SHORT 0x2000 /* lvalue is a short */
#define VT_LVAL_UNSIGNED 0x4000 /* lvalue is unsigned */ #define VT_LVAL_UNSIGNED 0x4000 /* lvalue is unsigned */
@ -2660,12 +2662,16 @@ void gbound(void)
vtop->r &= ~VT_MUSTBOUND; vtop->r &= ~VT_MUSTBOUND;
/* if lvalue, then use checking code before dereferencing */ /* if lvalue, then use checking code before dereferencing */
if (vtop->r & VT_LVAL) { if (vtop->r & VT_LVAL) {
lval_type = vtop->r & (VT_LVAL_TYPE | VT_LVAL); /* if not VT_BOUNDED value, then make one */
gaddrof(); if (!(vtop->r & VT_BOUNDED)) {
vpushi(0); lval_type = vtop->r & (VT_LVAL_TYPE | VT_LVAL);
gen_bounded_ptr_add1(); gaddrof();
gen_bounded_ptr_add2(1); vpushi(0);
vtop->r |= lval_type; gen_bounded_ptr_add();
vtop->r |= lval_type;
}
/* then check for dereferencing */
gen_bounded_ptr_deref();
} }
} }
#endif #endif
@ -3365,8 +3371,7 @@ void gen_op(int op)
vswap(); vswap();
gen_op('-'); gen_op('-');
} }
gen_bounded_ptr_add1(); gen_bounded_ptr_add();
gen_bounded_ptr_add2(0);
} else } else
#endif #endif
{ {