diff options
Diffstat (limited to 'src/lisp.h')
| -rw-r--r-- | src/lisp.h | 64 |
1 files changed, 60 insertions, 4 deletions
diff --git a/src/lisp.h b/src/lisp.h index add5312578b..2cb7a1fcc7f 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -248,6 +248,16 @@ Lisp_Object; #endif /* WORDS_BIG_ENDIAN */ +#ifdef __GNUC__ +static __inline__ Lisp_Object +LISP_MAKE_RVALUE (Lisp_Object o) +{ + return o; +} +#else +#define LISP_MAKE_RVALUE(o) (o) /* XXX - keeps arg as rvalue. */ +#endif + #endif /* NO_UNION_TYPE */ @@ -255,6 +265,7 @@ Lisp_Object; #ifdef NO_UNION_TYPE #define Lisp_Object EMACS_INT +#define LISP_MAKE_RVALUE(o) (0+(o)) #endif /* NO_UNION_TYPE */ #ifndef VALMASK @@ -616,14 +627,43 @@ struct Lisp_Cons }; /* Take the car or cdr of something known to be a cons cell. */ +/* The _AS_LVALUE macros shouldn't be used outside of the minimal set + of code that has to know what a cons cell looks like. Other code not + part of the basic lisp implementation should assume that the car and cdr + fields are not accessible as lvalues. (What if we want to switch to + a copying collector someday? Cached cons cell field addresses may be + invalidated at arbitrary points.) */ #ifdef HIDE_LISP_IMPLEMENTATION -#define XCAR(c) (XCONS ((c))->car_) -#define XCDR(c) (XCONS ((c))->cdr_) +#define XCAR_AS_LVALUE(c) (XCONS ((c))->car_) +#define XCDR_AS_LVALUE(c) (XCONS ((c))->cdr_) #else -#define XCAR(c) (XCONS ((c))->car) -#define XCDR(c) (XCONS ((c))->cdr) +#define XCAR_AS_LVALUE(c) (XCONS ((c))->car) +#define XCDR_AS_LVALUE(c) (XCONS ((c))->cdr) #endif +/* Okay, we're not quite ready to turn this on yet. A few files still + need to be updated and tested. */ +#undef LISP_MAKE_RVALUE +#define LISP_MAKE_RVALUE(x) (x) + +/* Use these from normal code. */ +#define XCAR(c) LISP_MAKE_RVALUE(XCAR_AS_LVALUE(c)) +#define XCDR(c) LISP_MAKE_RVALUE(XCDR_AS_LVALUE(c)) + +/* Use these to set the fields of a cons cell. + + Note that both arguments may refer to the same object, so 'n' + should not be read after 'c' is first modified. Also, neither + argument should be evaluated more than once; side effects are + especially common in the second argument. */ +#define XSETCAR(c,n) (XCAR_AS_LVALUE(c) = (n)) +#define XSETCDR(c,n) (XCDR_AS_LVALUE(c) = (n)) + +/* For performance: Fast storage of positive integers into the + fields of a cons cell. See above caveats. */ +#define XSETCARFASTINT(c,n) XSETFASTINT(XCAR_AS_LVALUE(c),(n)) +#define XSETCDRFASTINT(c,n) XSETFASTINT(XCDR_AS_LVALUE(c),(n)) + /* Take the car or cdr of something whose type is not known. */ #define CAR(c) \ (CONSP ((c)) ? XCAR ((c)) \ @@ -1474,6 +1514,22 @@ typedef unsigned char UCHAR; #define CHECK_OVERLAY(x, i) \ do { if (!OVERLAYP ((x))) x = wrong_type_argument (Qoverlayp, (x));} while (0) +/* Since we can't assign directly to the CAR or CDR fields of a cons + cell, use these when checking that those fields contain numbers. */ +#define CHECK_NUMBER_CAR(x, i) \ + do { \ + Lisp_Object tmp = XCAR (x); \ + CHECK_NUMBER (tmp, (i)); \ + XSETCAR ((x), tmp); \ + } while (0) + +#define CHECK_NUMBER_CDR(x, i) \ + do { \ + Lisp_Object tmp = XCDR (x); \ + CHECK_NUMBER (tmp, (i)); \ + XSETCDR ((x), tmp); \ + } while (0) + /* Cast pointers to this type to compare them. Some machines want int. */ #ifndef PNTR_COMPARISON_TYPE #define PNTR_COMPARISON_TYPE EMACS_UINT |