diff options
Diffstat (limited to 'gcc/bitmap.h')
| -rw-r--r-- | gcc/bitmap.h | 122 |
1 files changed, 121 insertions, 1 deletions
diff --git a/gcc/bitmap.h b/gcc/bitmap.h index 5e080af..6502acb 100644 --- a/gcc/bitmap.h +++ b/gcc/bitmap.h @@ -210,6 +210,7 @@ along with GCC; see the file COPYING3. If not see on which many random-access membership tests will happen. */ #include "obstack.h" +#include "array-traits.h" /* Bitmap memory usage. */ class bitmap_usage: public mem_usage @@ -435,7 +436,7 @@ extern bool bitmap_clear_bit (bitmap, int); extern bool bitmap_set_bit (bitmap, int); /* Return true if a bit is set in a bitmap. */ -extern int bitmap_bit_p (bitmap, int); +extern int bitmap_bit_p (const_bitmap, int); /* Debug functions to print a bitmap. */ extern void debug_bitmap (const_bitmap); @@ -956,4 +957,123 @@ class auto_bitmap bitmap_head m_bits; }; +/* Base class for bitmap_view; see there for details. */ +template<typename T, typename Traits = array_traits<T> > +class base_bitmap_view +{ +public: + typedef typename Traits::element_type array_element_type; + + base_bitmap_view (const T &, bitmap_element *); + operator const_bitmap () const { return &m_head; } + +private: + base_bitmap_view (const base_bitmap_view &); + + bitmap_head m_head; +}; + +/* Provides a read-only bitmap view of a single integer bitmask or a + constant-sized array of integer bitmasks, or of a wrapper around such + bitmasks. */ +template<typename T, typename Traits> +class bitmap_view<T, Traits, true> : public base_bitmap_view<T, Traits> +{ +public: + bitmap_view (const T &array) + : base_bitmap_view<T, Traits> (array, m_bitmap_elements) {} + +private: + /* How many bitmap_elements we need to hold a full T. */ + static const size_t num_bitmap_elements + = CEIL (CHAR_BIT + * sizeof (typename Traits::element_type) + * Traits::constant_size, + BITMAP_ELEMENT_ALL_BITS); + bitmap_element m_bitmap_elements[num_bitmap_elements]; +}; + +/* Initialize the view for array ARRAY, using the array of bitmap + elements in BITMAP_ELEMENTS (which is known to contain enough + entries). */ +template<typename T, typename Traits> +base_bitmap_view<T, Traits>::base_bitmap_view (const T &array, + bitmap_element *bitmap_elements) +{ + m_head.obstack = NULL; + + /* The code currently assumes that each element of ARRAY corresponds + to exactly one bitmap_element. */ + const size_t array_element_bits = CHAR_BIT * sizeof (array_element_type); + STATIC_ASSERT (BITMAP_ELEMENT_ALL_BITS % array_element_bits == 0); + size_t array_step = BITMAP_ELEMENT_ALL_BITS / array_element_bits; + size_t array_size = Traits::size (array); + + /* Process each potential bitmap_element in turn. The loop is written + this way rather than per array element because usually there are + only a small number of array elements per bitmap element (typically + two or four). The inner loops should therefore unroll completely. */ + const array_element_type *array_elements = Traits::base (array); + unsigned int indx = 0; + for (size_t array_base = 0; + array_base < array_size; + array_base += array_step, indx += 1) + { + /* How many array elements are in this particular bitmap_element. */ + unsigned int array_count + = (STATIC_CONSTANT_P (array_size % array_step == 0) + ? array_step : MIN (array_step, array_size - array_base)); + + /* See whether we need this bitmap element. */ + array_element_type ior = array_elements[array_base]; + for (size_t i = 1; i < array_count; ++i) + ior |= array_elements[array_base + i]; + if (ior == 0) + continue; + + /* Grab the next bitmap element and chain it. */ + bitmap_element *bitmap_element = bitmap_elements++; + if (m_head.current) + m_head.current->next = bitmap_element; + else + m_head.first = bitmap_element; + bitmap_element->prev = m_head.current; + bitmap_element->next = NULL; + bitmap_element->indx = indx; + m_head.current = bitmap_element; + m_head.indx = indx; + + /* Fill in the bits of the bitmap element. */ + if (array_element_bits < BITMAP_WORD_BITS) + { + /* Multiple array elements fit in one element of + bitmap_element->bits. */ + size_t array_i = array_base; + for (unsigned int word_i = 0; word_i < BITMAP_ELEMENT_WORDS; + ++word_i) + { + BITMAP_WORD word = 0; + for (unsigned int shift = 0; + shift < BITMAP_WORD_BITS && array_i < array_size; + shift += array_element_bits) + word |= array_elements[array_i++] << shift; + bitmap_element->bits[word_i] = word; + } + } + else + { + /* Array elements are the same size as elements of + bitmap_element->bits, or are an exact multiple of that size. */ + unsigned int word_i = 0; + for (unsigned int i = 0; i < array_count; ++i) + for (unsigned int shift = 0; shift < array_element_bits; + shift += BITMAP_WORD_BITS) + bitmap_element->bits[word_i++] + = array_elements[array_base + i] >> shift; + while (word_i < BITMAP_ELEMENT_WORDS) + bitmap_element->bits[word_i++] = 0; + } + } +} + #endif /* GCC_BITMAP_H */ |