diff options
Diffstat (limited to 'src/lisp.h')
| -rw-r--r-- | src/lisp.h | 62 |
1 files changed, 44 insertions, 18 deletions
diff --git a/src/lisp.h b/src/lisp.h index dae8123de5c..4cd2e69dac3 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -4562,11 +4562,27 @@ extern void *record_xmalloc (size_t) ATTRIBUTE_ALLOC_SIZE ((1)); } while (false) +/* Return floor (NBYTES / WORD_SIZE). */ + +INLINE ptrdiff_t +lisp_word_count (ptrdiff_t nbytes) +{ + if (-1 >> 1 == -1) + switch (word_size) + { + case 2: return nbytes >> 1; + case 4: return nbytes >> 2; + case 8: return nbytes >> 3; + case 16: return nbytes >> 4; + } + return nbytes / word_size - (nbytes % word_size < 0); +} + /* SAFE_ALLOCA_LISP allocates an array of Lisp_Objects. */ #define SAFE_ALLOCA_LISP(buf, nelt) \ do { \ - if ((nelt) <= sa_avail / word_size) \ + if ((nelt) <= lisp_word_count (sa_avail)) \ (buf) = AVAIL_ALLOCA ((nelt) * word_size); \ else if ((nelt) <= min (PTRDIFF_MAX, SIZE_MAX) / word_size) \ { \ @@ -4635,17 +4651,27 @@ verify (sizeof (struct Lisp_Cons) == sizeof (union Aligned_Cons)); # define USE_LOCAL_ALLOCATORS #endif +/* Any function that uses a local allocator should start with either + 'USE_SAFE_ALLOCA; or 'USE_LOCAL_ALLOCA;' (but not both). */ +#ifdef USE_LOCAL_ALLOCATORS +# define USE_LOCAL_ALLOCA ptrdiff_t sa_avail = MAX_ALLOCA +#else +# define USE_LOCAL_ALLOCA +#endif + #ifdef USE_LOCAL_ALLOCATORS /* Return a function-scoped cons whose car is X and cdr is Y. */ # define local_cons(x, y) \ - ({ \ - struct Lisp_Cons *c_ = alloca (sizeof (struct Lisp_Cons)); \ - c_->car = (x); \ - c_->u.cdr = (y); \ - make_lisp_ptr (c_, Lisp_Cons); \ - }) + (sizeof (struct Lisp_Cons) <= sa_avail \ + ? ({ \ + struct Lisp_Cons *c_ = AVAIL_ALLOCA (sizeof (struct Lisp_Cons)); \ + c_->car = (x); \ + c_->u.cdr = (y); \ + make_lisp_ptr (c_, Lisp_Cons); \ + }) \ + : Fcons (x, y)) # define local_list1(a) local_cons (a, Qnil) # define local_list2(a, b) local_cons (a, local_list1 (b)) @@ -4658,33 +4684,33 @@ verify (sizeof (struct Lisp_Cons) == sizeof (union Aligned_Cons)); # define make_local_vector(size, init) \ ({ \ ptrdiff_t size_ = size; \ - Lisp_Object init_ = init; \ Lisp_Object vec_; \ - if (size_ <= (MAX_ALLOCA - header_size) / word_size) \ + if (size_ <= lisp_word_count (sa_avail - header_size)) \ { \ - void *ptr_ = alloca (size_ * word_size + header_size); \ - vec_ = local_vector_init (ptr_, size_, init_); \ + void *ptr_ = AVAIL_ALLOCA (size_ * word_size + header_size); \ + vec_ = local_vector_init (ptr_, size_, init); \ } \ else \ - vec_ = Fmake_vector (make_number (size_), init_); \ + vec_ = Fmake_vector (make_number (size_), init); \ vec_; \ }) +enum { LISP_STRING_OVERHEAD = sizeof (struct Lisp_String) + 1 }; + /* Return a function-scoped string with contents DATA and length NBYTES. */ # define make_local_string(data, nbytes) \ ({ \ - char const *data_ = data; \ ptrdiff_t nbytes_ = nbytes; \ Lisp_Object string_; \ - if (nbytes_ <= MAX_ALLOCA - sizeof (struct Lisp_String) - 1) \ + if (nbytes_ <= sa_avail - LISP_STRING_OVERHEAD) \ { \ - struct Lisp_String *ptr_ \ - = alloca (sizeof (struct Lisp_String) + 1 + nbytes_); \ - string_ = local_string_init (ptr_, data_, nbytes_); \ + struct Lisp_String *ptr_ = AVAIL_ALLOCA (LISP_STRING_OVERHEAD \ + + nbytes_); \ + string_ = local_string_init (ptr_, data, nbytes_); \ } \ else \ - string_ = make_string (data_, nbytes_); \ + string_ = make_string (data, nbytes_); \ string_; \ }) |