mirror of
https://github.com/rust-lang/rust.git
synced 2025-01-02 02:46:06 +00:00
Refactored CastPass.
This commit is contained in:
R.Chavignat
parent
e80f2470b7
commit
3af2e3ba85
143
src/types.rs
143
src/types.rs
@ -134,6 +134,72 @@ fn is_isize_or_usize(typ: &ty::TyS) -> bool {
|
||||
}
|
||||
}
|
||||
|
||||
fn span_precision_loss_lint(cx: &Context, expr: &Expr, cast_from: &ty::TyS, cast_to_f64: bool) {
|
||||
let mantissa_nbits = if cast_to_f64 {52} else {23};
|
||||
let arch_dependent = is_isize_or_usize(cast_from) && cast_to_f64;
|
||||
let arch_dependent_str = "on targets with 64-bit wide pointers ";
|
||||
let from_nbits_str = if arch_dependent {"64".to_owned()}
|
||||
else if is_isize_or_usize(cast_from) {"32 or 64".to_owned()}
|
||||
else {int_ty_to_nbits(cast_from).to_string()};
|
||||
span_lint(cx, CAST_PRECISION_LOSS, expr.span,
|
||||
&format!("casting {0} to {1} causes a loss of precision {2}\
|
||||
({0} is {3} bits wide, but {1}'s mantissa is only {4} bits wide)",
|
||||
cast_from, if cast_to_f64 {"f64"} else {"f32"},
|
||||
if arch_dependent {arch_dependent_str} else {""},
|
||||
from_nbits_str,
|
||||
mantissa_nbits));
|
||||
}
|
||||
|
||||
enum ArchSuffix {
|
||||
_32, _64, None
|
||||
}
|
||||
|
||||
fn check_truncation_and_wrapping(cx: &Context, expr: &Expr, cast_from: &ty::TyS, cast_to: &ty::TyS) {
|
||||
let arch_64_suffix = " on targets with 64-bit wide pointers";
|
||||
let arch_32_suffix = " on targets with 32-bit wide pointers";
|
||||
let cast_unsigned_to_signed = !cast_from.is_signed() && cast_to.is_signed();
|
||||
let (from_nbits, to_nbits) = (int_ty_to_nbits(cast_from), int_ty_to_nbits(cast_to));
|
||||
let (span_truncation, suffix_truncation, span_wrap, suffix_wrap) =
|
||||
match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) {
|
||||
(true, true) | (false, false) => (
|
||||
to_nbits < from_nbits,
|
||||
ArchSuffix::None,
|
||||
to_nbits == from_nbits && cast_unsigned_to_signed,
|
||||
ArchSuffix::None
|
||||
),
|
||||
(true, false) => (
|
||||
to_nbits <= 32,
|
||||
if to_nbits == 32 {ArchSuffix::_64} else {ArchSuffix::None},
|
||||
to_nbits <= 32 && cast_unsigned_to_signed,
|
||||
ArchSuffix::_32
|
||||
),
|
||||
(false, true) => (
|
||||
from_nbits == 64,
|
||||
ArchSuffix::_32,
|
||||
cast_unsigned_to_signed,
|
||||
if from_nbits == 64 {ArchSuffix::_64} else {ArchSuffix::_32}
|
||||
),
|
||||
};
|
||||
if span_truncation {
|
||||
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
|
||||
&format!("casting {} to {} may truncate the value{}",
|
||||
cast_from, cast_to,
|
||||
match suffix_truncation {
|
||||
ArchSuffix::_32 => arch_32_suffix,
|
||||
ArchSuffix::_64 => arch_64_suffix,
|
||||
ArchSuffix::None => "" }));
|
||||
}
|
||||
if span_wrap {
|
||||
span_lint(cx, CAST_POSSIBLE_WRAP, expr.span,
|
||||
&format!("casting {} to {} may wrap around the value{}",
|
||||
cast_from, cast_to,
|
||||
match suffix_wrap {
|
||||
ArchSuffix::_32 => arch_32_suffix,
|
||||
ArchSuffix::_64 => arch_64_suffix,
|
||||
ArchSuffix::None => "" }));
|
||||
}
|
||||
}
|
||||
|
||||
impl LintPass for CastPass {
|
||||
fn get_lints(&self) -> LintArray {
|
||||
lint_array!(CAST_PRECISION_LOSS,
|
||||
@ -149,33 +215,9 @@ impl LintPass for CastPass {
|
||||
match (cast_from.is_integral(), cast_to.is_integral()) {
|
||||
(true, false) => {
|
||||
let from_nbits = int_ty_to_nbits(cast_from);
|
||||
let to_nbits : usize = match cast_to.sty {
|
||||
ty::TyFloat(ast::TyF32) => 32,
|
||||
ty::TyFloat(ast::TyF64) => 64,
|
||||
_ => 0
|
||||
};
|
||||
if from_nbits != 0 {
|
||||
// When casting to f32, precision loss would occur regardless of the arch
|
||||
if is_isize_or_usize(cast_from) {
|
||||
if to_nbits == 64 {
|
||||
span_lint(cx, CAST_PRECISION_LOSS, expr.span,
|
||||
&format!("casting {0} to f64 causes a loss of precision on targets with 64-bit wide pointers \
|
||||
({0} is 64 bits wide, but f64's mantissa is only 52 bits wide)",
|
||||
cast_from));
|
||||
}
|
||||
else {
|
||||
span_lint(cx, CAST_PRECISION_LOSS, expr.span,
|
||||
&format!("casting {0} to f32 causes a loss of precision \
|
||||
({0} is 32 or 64 bits wide, but f32's mantissa is only 23 bits wide)",
|
||||
cast_from));
|
||||
}
|
||||
}
|
||||
else if from_nbits >= to_nbits {
|
||||
span_lint(cx, CAST_PRECISION_LOSS, expr.span,
|
||||
&format!("casting {0} to {1} causes a loss of precision \
|
||||
({0} is {2} bits wide, but {1}'s mantissa is only {3} bits wide)",
|
||||
cast_from, cast_to, from_nbits, if to_nbits == 64 {52} else {23} ));
|
||||
}
|
||||
let to_nbits = if let ty::TyFloat(ast::TyF32) = cast_to.sty {32} else {64};
|
||||
if is_isize_or_usize(cast_from) || from_nbits >= to_nbits {
|
||||
span_precision_loss_lint(cx, expr, cast_from, to_nbits == 64);
|
||||
}
|
||||
},
|
||||
(false, true) => {
|
||||
@ -187,56 +229,11 @@ impl LintPass for CastPass {
|
||||
}
|
||||
},
|
||||
(true, true) => {
|
||||
let from_nbits = int_ty_to_nbits(cast_from);
|
||||
let to_nbits = int_ty_to_nbits(cast_to);
|
||||
if cast_from.is_signed() && !cast_to.is_signed() {
|
||||
span_lint(cx, CAST_SIGN_LOSS, expr.span,
|
||||
&format!("casting {} to {} may lose the sign of the value", cast_from, cast_to));
|
||||
}
|
||||
match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) {
|
||||
(true, true) | (false, false) =>
|
||||
if to_nbits < from_nbits {
|
||||
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
|
||||
&format!("casting {} to {} may truncate the value", cast_from, cast_to));
|
||||
}
|
||||
else if !cast_from.is_signed() && cast_to.is_signed() && to_nbits == from_nbits {
|
||||
span_lint(cx, CAST_POSSIBLE_WRAP, expr.span,
|
||||
&format!("casting {} to {} may wrap around the value", cast_from, cast_to));
|
||||
},
|
||||
(true, false) =>
|
||||
if to_nbits == 32 {
|
||||
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
|
||||
&format!("casting {} to {} may truncate the value on targets with 64-bit wide pointers",
|
||||
cast_from, cast_to));
|
||||
if !cast_from.is_signed() && cast_to.is_signed() {
|
||||
span_lint(cx, CAST_POSSIBLE_WRAP, expr.span,
|
||||
&format!("casting {} to {} may wrap around the value on targets with 32-bit wide pointers",
|
||||
cast_from, cast_to));
|
||||
}
|
||||
}
|
||||
else if to_nbits < 32 {
|
||||
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
|
||||
&format!("casting {} to {} may truncate the value", cast_from, cast_to));
|
||||
},
|
||||
(false, true) =>
|
||||
if from_nbits == 64 {
|
||||
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span,
|
||||
&format!("casting {} to {} may truncate the value on targets with 32-bit wide pointers",
|
||||
cast_from, cast_to));
|
||||
if !cast_from.is_signed() && cast_to.is_signed() {
|
||||
span_lint(cx, CAST_POSSIBLE_WRAP, expr.span,
|
||||
&format!("casting {} to {} may wrap around the value on targets with 64-bit wide pointers",
|
||||
cast_from, cast_to));
|
||||
}
|
||||
}
|
||||
else {
|
||||
if !cast_from.is_signed() && cast_to.is_signed() {
|
||||
span_lint(cx, CAST_POSSIBLE_WRAP, expr.span,
|
||||
&format!("casting {} to {} may wrap around the value on targets with 32-bit wide pointers",
|
||||
cast_from, cast_to));
|
||||
}
|
||||
}
|
||||
}
|
||||
check_truncation_and_wrapping(cx, expr, cast_from, cast_to);
|
||||
}
|
||||
(false, false) => {
|
||||
if let (&ty::TyFloat(ast::TyF64),
|
||||
|
||||
Loading…
Reference in New Issue
Block a user