diff options
Diffstat (limited to 'gcc/ada/decl.c')
| -rw-r--r-- | gcc/ada/decl.c | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/gcc/ada/decl.c b/gcc/ada/decl.c index 2d4742dd06b..bc5d4283053 100644 --- a/gcc/ada/decl.c +++ b/gcc/ada/decl.c @@ -672,19 +672,42 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition) && !Present (Address_Clause (gnat_entity))) gnu_size = bitsize_unit_node; - /* If this is an atomic object with no specified size and alignment, - but where the size of the type is a constant, set the alignment to - the smallest not less than the size, or to the biggest meaningful - alignment, whichever is smaller. */ - if (Is_Atomic (gnat_entity) && !gnu_size && align == 0 + /* If this is an object with no specified size and alignment, and if + either it is atomic or we are not optimizing alignment for space + and it is a non-scalar variable, and the size of its type is a + constant, set the alignment to the smallest not less than the + size, or to the biggest meaningful one, whichever is smaller. */ + if (!gnu_size && align == 0 + && (Is_Atomic (gnat_entity) + || (Debug_Flag_Dot_A + && !Optimize_Alignment_Space (gnat_entity) + && kind == E_Variable + && AGGREGATE_TYPE_P (gnu_type) + && !const_flag && No (Renamed_Object (gnat_entity)) + && !imported_p && No (Address_Clause (gnat_entity)))) && TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST) { + /* No point in jumping through all the hoops needed in order + to support BIGGEST_ALIGNMENT if we don't really have to. */ + unsigned int align_cap = Is_Atomic (gnat_entity) + ? BIGGEST_ALIGNMENT + : MAX_FIXED_MODE_SIZE; + if (!host_integerp (TYPE_SIZE (gnu_type), 1) - || 0 <= compare_tree_int (TYPE_SIZE (gnu_type), - BIGGEST_ALIGNMENT)) - align = BIGGEST_ALIGNMENT; + || compare_tree_int (TYPE_SIZE (gnu_type), align_cap) >= 0) + align = align_cap; else align = ceil_alignment (tree_low_cst (TYPE_SIZE (gnu_type), 1)); + + /* But make sure not to under-align the object. */ + if (align < TYPE_ALIGN (gnu_type)) + align = TYPE_ALIGN (gnu_type); + + /* And honor the minimum valid atomic alignment, if any. */ +#ifdef MINIMUM_ATOMIC_ALIGNMENT + if (align < MINIMUM_ATOMIC_ALIGNMENT) + align = MINIMUM_ATOMIC_ALIGNMENT; +#endif } /* If the object is set to have atomic components, find the component |