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Cleanup build_sizeof_expr #6664

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Merged
merged 2 commits into from
Feb 14, 2022
Merged

Cleanup build_sizeof_expr #6664

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85d99a4
Move build_sizeof_expr to expr2c
tautschnig Feb 14, 2022
673bd73
Cleanup build_sizeof_expr
tautschnig Feb 14, 2022
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52 changes: 48 additions & 4 deletions src/ansi-c/expr2c.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1728,6 +1728,52 @@ std::string expr2ct::convert_object_descriptor(
return result;
}

static optionalt<exprt>
build_sizeof_expr(const constant_exprt &expr, const namespacet &ns)
{
const typet &type = static_cast<const typet &>(expr.find(ID_C_c_sizeof_type));

if(type.is_nil())
return {};

const auto type_size_expr = size_of_expr(type, ns);
optionalt<mp_integer> type_size;
if(type_size_expr.has_value())
type_size = numeric_cast<mp_integer>(*type_size_expr);
auto val = numeric_cast<mp_integer>(expr);

if(
!type_size.has_value() || *type_size < 0 || !val.has_value() ||
*val < *type_size || (*type_size == 0 && *val > 0))
{
return {};
}

const unsignedbv_typet t(size_type());
DATA_INVARIANT(
address_bits(*val + 1) <= t.get_width(),
"sizeof value does not fit size_type");

mp_integer remainder = 0;

if(*type_size != 0)
{
remainder = *val % *type_size;
*val -= remainder;
*val /= *type_size;
}

exprt result(ID_sizeof, t);
result.set(ID_type_arg, type);

if(*val > 1)
result = mult_exprt(result, from_integer(*val, t));
if(remainder > 0)
result = plus_exprt(result, from_integer(remainder, t));

return typecast_exprt::conditional_cast(result, expr.type());
}

std::string expr2ct::convert_constant(
const constant_exprt &src,
unsigned &precedence)
Expand Down Expand Up @@ -1852,11 +1898,9 @@ std::string expr2ct::convert_constant(
else if(c_type==ID_signed_long_long_int)
dest+="ll";

if(src.find(ID_C_c_sizeof_type).is_not_nil() &&
sizeof_nesting==0)
if(sizeof_nesting == 0)
{
const auto sizeof_expr_opt =
build_sizeof_expr(to_constant_expr(src), ns);
const auto sizeof_expr_opt = build_sizeof_expr(src, ns);

if(sizeof_expr_opt.has_value())
{
Expand Down
44 changes: 0 additions & 44 deletions src/util/pointer_offset_size.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -560,50 +560,6 @@ compute_pointer_offset(const exprt &expr, const namespacet &ns)
return {}; // don't know
}

optionalt<exprt>
build_sizeof_expr(const constant_exprt &expr, const namespacet &ns)
{
const typet &type=
static_cast<const typet &>(expr.find(ID_C_c_sizeof_type));

if(type.is_nil())
return {};

const auto type_size = pointer_offset_size(type, ns);
auto val = numeric_cast<mp_integer>(expr);

if(
!type_size.has_value() || *type_size < 0 || !val.has_value() ||
*val < *type_size || (*type_size == 0 && *val > 0))
{
return {};
}

const typet t(size_type());
DATA_INVARIANT(
address_bits(*val + 1) <= *pointer_offset_bits(t, ns),
"sizeof value does not fit size_type");

mp_integer remainder=0;

if(*type_size != 0)
{
remainder = *val % *type_size;
*val -= remainder;
*val /= *type_size;
}

exprt result(ID_sizeof, t);
result.set(ID_type_arg, type);

if(*val > 1)
result = mult_exprt(result, from_integer(*val, t));
if(remainder>0)
result=plus_exprt(result, from_integer(remainder, t));

return typecast_exprt::conditional_cast(result, expr.type());
}

optionalt<exprt> get_subexpression_at_offset(
const exprt &expr,
const mp_integer &offset_bytes,
Expand Down
3 changes: 0 additions & 3 deletions src/util/pointer_offset_size.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,6 @@ optionalt<exprt> member_offset_expr(

optionalt<exprt> size_of_expr(const typet &type, const namespacet &ns);

optionalt<exprt>
build_sizeof_expr(const constant_exprt &expr, const namespacet &ns);

optionalt<exprt> get_subexpression_at_offset(
const exprt &expr,
const mp_integer &offset,
Expand Down