diff options
Diffstat (limited to 'gcc-4.8/gcc/tree-dfa.c')
| -rw-r--r-- | gcc-4.8/gcc/tree-dfa.c | 95 |
1 files changed, 42 insertions, 53 deletions
diff --git a/gcc-4.8/gcc/tree-dfa.c b/gcc-4.8/gcc/tree-dfa.c index 23fae4f2d..28233b252 100644 --- a/gcc-4.8/gcc/tree-dfa.c +++ b/gcc-4.8/gcc/tree-dfa.c @@ -386,7 +386,6 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, double_int bit_offset = double_int_zero; HOST_WIDE_INT hbit_offset; bool seen_variable_array_ref = false; - tree base_type; /* First get the final access size from just the outermost expression. */ if (TREE_CODE (exp) == COMPONENT_REF) @@ -417,8 +416,6 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, and find the ultimate containing object. */ while (1) { - base_type = TREE_TYPE (exp); - switch (TREE_CODE (exp)) { case BIT_FIELD_REF: @@ -543,54 +540,54 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, case VIEW_CONVERT_EXPR: break; - case MEM_REF: - /* Hand back the decl for MEM[&decl, off]. */ - if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR) - { - if (integer_zerop (TREE_OPERAND (exp, 1))) - exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0); - else - { - double_int off = mem_ref_offset (exp); - off = off.alshift (BITS_PER_UNIT == 8 - ? 3 : exact_log2 (BITS_PER_UNIT), - HOST_BITS_PER_DOUBLE_INT); - off = off + bit_offset; - if (off.fits_shwi ()) - { - bit_offset = off; - exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0); - } - } - } - goto done; - case TARGET_MEM_REF: - /* Hand back the decl for MEM[&decl, off]. */ - if (TREE_CODE (TMR_BASE (exp)) == ADDR_EXPR) - { /* Via the variable index or index2 we can reach the - whole object. */ - if (TMR_INDEX (exp) || TMR_INDEX2 (exp)) + whole object. Still hand back the decl here. */ + if (TREE_CODE (TMR_BASE (exp)) == ADDR_EXPR + && (TMR_INDEX (exp) || TMR_INDEX2 (exp))) { exp = TREE_OPERAND (TMR_BASE (exp), 0); bit_offset = double_int_zero; maxsize = -1; goto done; } - if (integer_zerop (TMR_OFFSET (exp))) - exp = TREE_OPERAND (TMR_BASE (exp), 0); + /* Fallthru. */ + case MEM_REF: + /* We need to deal with variable arrays ending structures such as + struct { int length; int a[1]; } x; x.a[d] + struct { struct { int a; int b; } a[1]; } x; x.a[d].a + struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0] + struct { int len; union { int a[1]; struct X x; } u; } x; x.u.a[d] + where we do not know maxsize for variable index accesses to + the array. The simplest way to conservatively deal with this + is to punt in the case that offset + maxsize reaches the + base type boundary. This needs to include possible trailing + padding that is there for alignment purposes. */ + if (seen_variable_array_ref + && maxsize != -1 + && (!bit_offset.fits_shwi () + || !host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1) + || (bit_offset.to_shwi () + maxsize + == (HOST_WIDE_INT) TREE_INT_CST_LOW + (TYPE_SIZE (TREE_TYPE (exp)))))) + maxsize = -1; + + /* Hand back the decl for MEM[&decl, off]. */ + if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR) + { + if (integer_zerop (TREE_OPERAND (exp, 1))) + exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0); else { double_int off = mem_ref_offset (exp); off = off.alshift (BITS_PER_UNIT == 8 ? 3 : exact_log2 (BITS_PER_UNIT), HOST_BITS_PER_DOUBLE_INT); - off += bit_offset; + off = off + bit_offset; if (off.fits_shwi ()) { bit_offset = off; - exp = TREE_OPERAND (TMR_BASE (exp), 0); + exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0); } } } @@ -602,8 +599,18 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, exp = TREE_OPERAND (exp, 0); } - done: + /* We need to deal with variable arrays ending structures. */ + if (seen_variable_array_ref + && maxsize != -1 + && (!bit_offset.fits_shwi () + || !host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1) + || (bit_offset.to_shwi () + maxsize + == (HOST_WIDE_INT) + TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp)))))) + maxsize = -1; + + done: if (!bit_offset.fits_shwi ()) { *poffset = 0; @@ -615,24 +622,6 @@ get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, hbit_offset = bit_offset.to_shwi (); - /* We need to deal with variable arrays ending structures such as - struct { int length; int a[1]; } x; x.a[d] - struct { struct { int a; int b; } a[1]; } x; x.a[d].a - struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0] - struct { int len; union { int a[1]; struct X x; } u; } x; x.u.a[d] - where we do not know maxsize for variable index accesses to - the array. The simplest way to conservatively deal with this - is to punt in the case that offset + maxsize reaches the - base type boundary. This needs to include possible trailing padding - that is there for alignment purposes. */ - - if (seen_variable_array_ref - && maxsize != -1 - && (!host_integerp (TYPE_SIZE (base_type), 1) - || (hbit_offset + maxsize - == (signed) TREE_INT_CST_LOW (TYPE_SIZE (base_type))))) - maxsize = -1; - /* In case of a decl or constant base object we can do better. */ if (DECL_P (exp)) |