From: David Given <dg@xxxxxxxxxxx>
---
Hello.
It turns out, there was a bug in this irivial patch, which
lead to discovery of an other bug in sparse.
First, i >> 3 != i / 8 when i < 0, and sym->bit_size
may actually quite often be -1:
symbol.c:878 unsigned long bit_size = ctype->bit_size ? *ctype->bit_size : -1;
[...]
symbol.c:885 sym->bit_size = bit_size;
This problem may be addressed by changing bits_to_bytes to
static inline int bits_to_bytes(int bits)
{
return bits >= 0 ? bits / bits_in_char : -1;
}
Which I think is ok if it helps Davind with his work,
and I doubt anybody could measure any slowdown here.
But it seems there is also a bug in sparse, as in
ctype_declaration[] the bit_size of void_ctype is
set to NULL, while gcc assumes sizeof(void) being 1.
Currently sparse would generate wrong code for:
void *test(void *p) {
p++;
return p;
}
unsigned long test1(void *p)
{
return sizeof(*p);
}
.L0x2b48867c1010:
<entry-point>
add.32 %r2 <- %arg1, $-1
ret.32 %r2
test1:
.L0x2b48867c10b0:
<entry-point>
ret.32 $-1
And with bit_size set to &bits_in_char, the code looks
as expected. But I don't really understand this
ctype-symbol stuff, so the fix needs more review.
Anyway, here is the updated byte size patch.
David, we still need your sign-off here.
compile-i386.c | 2 +-
evaluate.c | 26 +++++++++++++-------------
example.c | 2 +-
expand.c | 2 +-
flow.c | 10 ++++++----
show-parse.c | 2 +-
symbol.c | 10 +++++-----
target.h | 14 ++++++++++++++
8 files changed, 42 insertions(+), 26 deletions(-)
diff --git a/compile-i386.c b/compile-i386.c
index 8526408..37ea52e 100644
--- a/compile-i386.c
+++ b/compile-i386.c
@@ -2081,7 +2081,7 @@ static struct storage *x86_call_expression(struct expression *expr)
insn("pushl", new, NULL,
!framesize ? "begin function call" : NULL);
- framesize += size >> 3;
+ framesize += bits_to_bytes(size);
} END_FOR_EACH_PTR_REVERSE(arg);
fn = expr->fn;
diff --git a/evaluate.c b/evaluate.c
index e17da53..c501323 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -72,7 +72,7 @@ static struct symbol *evaluate_string(struct expression *expr)
unsigned int length = expr->string->length;
sym->array_size = alloc_const_expression(expr->pos, length);
- sym->bit_size = bits_in_char * length;
+ sym->bit_size = bytes_to_bits(length);
sym->ctype.alignment = 1;
sym->string = 1;
sym->ctype.modifiers = MOD_STATIC;
@@ -83,7 +83,7 @@ static struct symbol *evaluate_string(struct expression *expr)
initstr->string = expr->string;
array->array_size = sym->array_size;
- array->bit_size = bits_in_char * length;
+ array->bit_size = bytes_to_bits(length);
array->ctype.alignment = 1;
array->ctype.modifiers = MOD_STATIC;
array->ctype.base_type = &char_ctype;
@@ -579,7 +579,7 @@ static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *i
}
/* Get the size of whatever the pointer points to */
- multiply = base->bit_size >> 3;
+ multiply = bits_to_bytes(base->bit_size);
if (ctype == &null_ctype)
ctype = &ptr_ctype;
@@ -831,7 +831,7 @@ static struct symbol *evaluate_ptr_sub(struct expression *expr)
struct expression *sub = alloc_expression(expr->pos, EXPR_BINOP);
struct expression *div = expr;
struct expression *val = alloc_expression(expr->pos, EXPR_VALUE);
- unsigned long value = lbase->bit_size >> 3;
+ unsigned long value = bits_to_bytes(lbase->bit_size);
val->ctype = size_t_ctype;
val->value = value;
@@ -1591,7 +1591,7 @@ static struct symbol *degenerate(struct expression *expr)
e3->op = '+';
e3->left = e0;
e3->right = alloc_const_expression(expr->pos,
- expr->r_bitpos >> 3);
+ bits_to_bytes(expr->r_bitpos));
e3->ctype = &lazy_ptr_ctype;
} else {
e3 = e0;
@@ -1727,7 +1727,7 @@ static struct symbol *evaluate_postop(struct expression *expr)
} else if (class == TYPE_PTR) {
struct symbol *target = examine_pointer_target(ctype);
if (!is_function(target))
- multiply = target->bit_size >> 3;
+ multiply = bits_to_bytes(target->bit_size);
}
if (multiply) {
@@ -1949,7 +1949,7 @@ static struct symbol *evaluate_member_dereference(struct expression *expr)
expr->base = deref->base;
expr->r_bitpos = deref->r_bitpos;
}
- expr->r_bitpos += offset << 3;
+ expr->r_bitpos += bytes_to_bits(offset);
expr->type = EXPR_SLICE;
expr->r_nrbits = member->bit_size;
expr->r_bitpos += member->bit_offset;
@@ -2037,10 +2037,10 @@ static struct symbol *evaluate_sizeof(struct expression *expr)
return NULL;
size = type->bit_size;
- if ((size < 0) || (size & 7))
+ if ((size < 0) || (size & (bits_in_char - 1)))
expression_error(expr, "cannot size expression");
expr->type = EXPR_VALUE;
- expr->value = size >> 3;
+ expr->value = bits_to_bytes(size);
expr->taint = 0;
expr->ctype = size_t_ctype;
return size_t_ctype;
@@ -2071,10 +2071,10 @@ static struct symbol *evaluate_ptrsizeof(struct expression *expr)
return NULL;
}
size = type->bit_size;
- if (size & 7)
+ if (size & (bits_in_char-1))
size = 0;
expr->type = EXPR_VALUE;
- expr->value = size >> 3;
+ expr->value = bits_to_bytes(size);
expr->taint = 0;
expr->ctype = size_t_ctype;
return size_t_ctype;
@@ -2158,7 +2158,7 @@ static void convert_index(struct expression *e)
unsigned from = e->idx_from;
unsigned to = e->idx_to + 1;
e->type = EXPR_POS;
- e->init_offset = from * (e->ctype->bit_size>>3);
+ e->init_offset = from * bits_to_bytes(e->ctype->bit_size);
e->init_nr = to - from;
e->init_expr = child;
}
@@ -2865,7 +2865,7 @@ static struct symbol *evaluate_offsetof(struct expression *expr)
unrestrict(idx, i_class, &i_type);
idx = cast_to(idx, size_t_ctype);
m = alloc_const_expression(expr->pos,
- ctype->bit_size >> 3);
+ bits_to_bytes(ctype->bit_size));
m->ctype = size_t_ctype;
m->flags = Int_const_expr;
expr->type = EXPR_BINOP;
diff --git a/example.c b/example.c
index ae897dc..24444c6 100644
--- a/example.c
+++ b/example.c
@@ -1830,7 +1830,7 @@ static void set_up_arch_entry(struct entrypoint *ep, struct instruction *entry)
in->type = REG_FRAME;
in->offset = offset;
- offset += bits >> 3;
+ offset += bits_to_bytes(bits);
}
i++;
NEXT_PTR_LIST(argtype);
diff --git a/expand.c b/expand.c
index 032f0c5..3e962d1 100644
--- a/expand.c
+++ b/expand.c
@@ -880,7 +880,7 @@ static unsigned long bit_offset(const struct expression *expr)
{
unsigned long offset = 0;
while (expr->type == EXPR_POS) {
- offset += expr->init_offset << 3;
+ offset += bytes_to_bits(expr->init_offset);
expr = expr->init_expr;
}
if (expr && expr->ctype)
diff --git a/flow.c b/flow.c
index 82fb23a..5bd9a1d 100644
--- a/flow.c
+++ b/flow.c
@@ -16,6 +16,7 @@
#include "expression.h"
#include "linearize.h"
#include "flow.h"
+#include "target.h"
unsigned long bb_generation;
@@ -265,8 +266,8 @@ void convert_load_instruction(struct instruction *insn, pseudo_t src)
static int overlapping_memop(struct instruction *a, struct instruction *b)
{
- unsigned int a_start = a->offset << 3;
- unsigned int b_start = b->offset << 3;
+ unsigned int a_start = bytes_to_bits(a->offset);
+ unsigned int b_start = bytes_to_bits(b->offset);
unsigned int a_size = a->size;
unsigned int b_size = b->size;
@@ -581,13 +582,14 @@ void check_access(struct instruction *insn)
pseudo_t pseudo = insn->src;
if (insn->bb && pseudo->type == PSEUDO_SYM) {
- int offset = insn->offset, bit = (offset << 3) + insn->size;
+ int offset = insn->offset, bit = bytes_to_bits(offset) + insn->size;
struct symbol *sym = pseudo->sym;
if (sym->bit_size > 0 && (offset < 0 || bit > sym->bit_size))
warning(insn->pos, "invalid access %s '%s' (%d %d)",
offset < 0 ? "below" : "past the end of",
- show_ident(sym->ident), offset, sym->bit_size >> 3);
+ show_ident(sym->ident), offset,
+ bits_to_bytes(sym->bit_size));
}
}
diff --git a/show-parse.c b/show-parse.c
index 064af32..c79a288 100644
--- a/show-parse.c
+++ b/show-parse.c
@@ -673,7 +673,7 @@ static int show_call_expression(struct expression *expr)
int new = show_expression(arg);
int size = arg->ctype->bit_size;
printf("\tpush.%d\t\tv%d\n", size, new);
- framesize += size >> 3;
+ framesize += bits_to_bytes(size);
} END_FOR_EACH_PTR_REVERSE(arg);
fn = expr->fn;
diff --git a/symbol.c b/symbol.c
index 3292907..49560ee 100644
--- a/symbol.c
+++ b/symbol.c
@@ -128,7 +128,7 @@ static void lay_out_struct(struct symbol *sym, struct struct_union_info *info)
base_size = 0;
}
- align_bit_mask = (sym->ctype.alignment << 3) - 1;
+ align_bit_mask = bytes_to_bits(sym->ctype.alignment) - 1;
/*
* Bitfields have some very special rules..
@@ -143,7 +143,7 @@ static void lay_out_struct(struct symbol *sym, struct struct_union_info *info)
bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
bit_offset = 0;
}
- sym->offset = (bit_size - bit_offset) >> 3;
+ sym->offset = bits_to_bytes(bit_size - bit_offset);
sym->bit_offset = bit_offset;
sym->ctype.base_type->bit_offset = bit_offset;
info->bit_size = bit_size + width;
@@ -156,7 +156,7 @@ static void lay_out_struct(struct symbol *sym, struct struct_union_info *info)
* Otherwise, just align it right and add it up..
*/
bit_size = (bit_size + align_bit_mask) & ~align_bit_mask;
- sym->offset = bit_size >> 3;
+ sym->offset = bits_to_bytes(bit_size);
info->bit_size = bit_size + base_size;
// warning (sym->pos, "regular: offset=%d", sym->offset);
@@ -182,7 +182,7 @@ static struct symbol * examine_struct_union_type(struct symbol *sym, int advance
sym->ctype.alignment = info.max_align;
bit_size = info.bit_size;
if (info.align_size) {
- bit_align = (sym->ctype.alignment << 3)-1;
+ bit_align = bytes_to_bits(sym->ctype.alignment)-1;
bit_size = (bit_size + bit_align) & ~bit_align;
}
sym->bit_size = bit_size;
@@ -877,7 +877,7 @@ void init_ctype(void)
struct symbol *sym = ctype->ptr;
unsigned long bit_size = ctype->bit_size ? *ctype->bit_size : -1;
unsigned long maxalign = ctype->maxalign ? *ctype->maxalign : 0;
- unsigned long alignment = (bit_size + 7) >> 3;
+ unsigned long alignment = bits_to_bytes(bit_size + bits_in_char - 1);
if (alignment > maxalign)
alignment = maxalign;
diff --git a/target.h b/target.h
index 25f7948..7f0fd27 100644
--- a/target.h
+++ b/target.h
@@ -42,4 +42,18 @@ extern int pointer_alignment;
extern int bits_in_enum;
extern int enum_alignment;
+/*
+ * Helper functions for converting bits to bytes and vice versa.
+ */
+
+static inline int bits_to_bytes(int bits)
+{
+ return bits >= 0 ? bits / bits_in_char : -1;
+}
+
+static inline int bytes_to_bits(int bytes)
+{
+ return bytes * bits_in_char;
+}
+
#endif
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