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Move cast_ptr_alignment to its own module

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This commit is contained in:
Yoshitomo Nakanishi 2021-03-09 17:15:18 +09:00
parent 9a24877e2c
commit ebd1ec0e40
2 changed files with 85 additions and 63 deletions
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81
clippy_lints/src/casts/cast_ptr_alignment.rs Normal file
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@ -0,0 +1,81 @@
use rustc_hir::{Expr, ExprKind, GenericArg};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use rustc_span::symbol::sym;
use rustc_target::abi::LayoutOf;
use if_chain::if_chain;
use crate::utils::{is_hir_ty_cfg_dependant, span_lint};
use super::CAST_PTR_ALIGNMENT;
pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let ExprKind::Cast(ref cast_expr, cast_to) = expr.kind {
if is_hir_ty_cfg_dependant(cx, cast_to) {
return;
}
let (cast_from, cast_to) = (
cx.typeck_results().expr_ty(cast_expr),
cx.typeck_results().expr_ty(expr),
);
lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
} else if let ExprKind::MethodCall(method_path, _, args, _) = expr.kind {
if_chain! {
if method_path.ident.name == sym!(cast);
if let Some(generic_args) = method_path.args;
if let [GenericArg::Type(cast_to)] = generic_args.args;
// There probably is no obvious reason to do this, just to be consistent with `as` cases.
if !is_hir_ty_cfg_dependant(cx, cast_to);
then {
let (cast_from, cast_to) =
(cx.typeck_results().expr_ty(&args[0]), cx.typeck_results().expr_ty(expr));
lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
}
}
}
}
fn lint_cast_ptr_alignment<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, cast_from: Ty<'tcx>, cast_to: Ty<'tcx>) {
if_chain! {
if let ty::RawPtr(from_ptr_ty) = &cast_from.kind();
if let ty::RawPtr(to_ptr_ty) = &cast_to.kind();
if let Ok(from_layout) = cx.layout_of(from_ptr_ty.ty);
if let Ok(to_layout) = cx.layout_of(to_ptr_ty.ty);
if from_layout.align.abi < to_layout.align.abi;
// with c_void, we inherently need to trust the user
if !is_c_void(cx, from_ptr_ty.ty);
// when casting from a ZST, we don't know enough to properly lint
if !from_layout.is_zst();
then {
span_lint(
cx,
CAST_PTR_ALIGNMENT,
expr.span,
&format!(
"casting from `{}` to a more-strictly-aligned pointer (`{}`) ({} < {} bytes)",
cast_from,
cast_to,
from_layout.align.abi.bytes(),
to_layout.align.abi.bytes(),
),
);
}
}
}
/// Check if the given type is either `core::ffi::c_void` or
/// one of the platform specific `libc::<platform>::c_void` of libc.
fn is_c_void(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
if let ty::Adt(adt, _) = ty.kind() {
let names = cx.get_def_path(adt.did);
if names.is_empty() {
return false;
}
if names[0] == sym::libc || names[0] == sym::core && *names.last().unwrap() == sym!(c_void) {
return true;
}
}
false
}

67
clippy_lints/src/casts/mod.rs
View File

@ -2,6 +2,7 @@
mod cast_possible_truncation;
mod cast_possible_wrap;
mod cast_precision_loss;
mod cast_ptr_alignment;
mod cast_sign_loss;
mod fn_to_numeric_cast;
mod fn_to_numeric_cast_with_truncation;
@ -13,22 +14,18 @@
use if_chain::if_chain;
use rustc_ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind, GenericArg, MutTy, Mutability, TyKind, UnOp};
use rustc_hir::{Expr, ExprKind, MutTy, Mutability, TyKind, UnOp};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty::{self, Ty, TypeAndMut, UintTy};
use rustc_middle::ty::{self, TypeAndMut, UintTy};
use rustc_semver::RustcVersion;
use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass};
use rustc_span::symbol::sym;
use rustc_target::abi::LayoutOf;
use crate::utils::sugg::Sugg;
use crate::utils::{
is_hir_ty_cfg_dependant, meets_msrv, snippet_with_applicability, span_lint, span_lint_and_sugg, span_lint_and_then,
};
use utils::int_ty_to_nbits;
declare_clippy_lint! {
/// **What it does:** Checks for casts from any numerical to a float type where
/// the receiving type cannot store all values from the original type without
@ -270,22 +267,6 @@
FN_TO_NUMERIC_CAST_WITH_TRUNCATION,
]);
/// Check if the given type is either `core::ffi::c_void` or
/// one of the platform specific `libc::<platform>::c_void` of libc.
fn is_c_void(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
if let ty::Adt(adt, _) = ty.kind() {
let names = cx.get_def_path(adt.did);
if names.is_empty() {
return false;
}
if names[0] == sym::libc || names[0] == sym::core && *names.last().unwrap() == sym!(c_void) {
return true;
}
}
false
}
impl<'tcx> LateLintPass<'tcx> for Casts {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if expr.span.from_expansion() {
@ -306,7 +287,6 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
fn_to_numeric_cast::check(cx, expr, cast_expr, cast_from, cast_to);
fn_to_numeric_cast_with_truncation::check(cx, expr, cast_expr, cast_from, cast_to);
lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
if cast_from.is_numeric() && cast_to.is_numeric() && !in_external_macro(cx.sess(), expr.span) {
cast_possible_truncation::check(cx, expr, cast_from, cast_to);
cast_possible_wrap::check(cx, expr, cast_from, cast_to);
@ -314,48 +294,9 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to);
cast_sign_loss::check(cx, expr, cast_expr, cast_from, cast_to);
}
} else if let ExprKind::MethodCall(method_path, _, args, _) = expr.kind {
if_chain! {
if method_path.ident.name == sym!(cast);
if let Some(generic_args) = method_path.args;
if let [GenericArg::Type(cast_to)] = generic_args.args;
// There probably is no obvious reason to do this, just to be consistent with `as` cases.
if !is_hir_ty_cfg_dependant(cx, cast_to);
then {
let (cast_from, cast_to) =
(cx.typeck_results().expr_ty(&args[0]), cx.typeck_results().expr_ty(expr));
lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
}
}
}
}
}
fn lint_cast_ptr_alignment<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, cast_from: Ty<'tcx>, cast_to: Ty<'tcx>) {
if_chain! {
if let ty::RawPtr(from_ptr_ty) = &cast_from.kind();
if let ty::RawPtr(to_ptr_ty) = &cast_to.kind();
if let Ok(from_layout) = cx.layout_of(from_ptr_ty.ty);
if let Ok(to_layout) = cx.layout_of(to_ptr_ty.ty);
if from_layout.align.abi < to_layout.align.abi;
// with c_void, we inherently need to trust the user
if !is_c_void(cx, from_ptr_ty.ty);
// when casting from a ZST, we don't know enough to properly lint
if !from_layout.is_zst();
then {
span_lint(
cx,
CAST_PTR_ALIGNMENT,
expr.span,
&format!(
"casting from `{}` to a more-strictly-aligned pointer (`{}`) ({} < {} bytes)",
cast_from,
cast_to,
from_layout.align.abi.bytes(),
to_layout.align.abi.bytes(),
),
);
}
cast_ptr_alignment::check(cx, expr);
}
}