From 391bb218b5a79f32ddfacc668838fdfb06835f77 Mon Sep 17 00:00:00 2001 From: Marijn Suijten Date: Tue, 19 Jan 2021 19:20:26 +0100 Subject: [PATCH 1/2] size_of_in_element_count: Separate test file in expressions and functions An upcoming test case for new expresssion variants make the stderr file go over 200 lines. Split this test case in two to have a clear distinction between checking whether the lint is still applying on all the functions with member counts as argument, versus validating various member-count expressions that may or may not be invalid. --- .../size_of_in_element_count/expressions.rs | 28 ++++++++ .../expressions.stderr | 27 ++++++++ .../functions.rs} | 15 ---- .../functions.stderr} | 68 ++++++------------- 4 files changed, 77 insertions(+), 61 deletions(-) create mode 100644 tests/ui/size_of_in_element_count/expressions.rs create mode 100644 tests/ui/size_of_in_element_count/expressions.stderr rename tests/ui/{size_of_in_element_count.rs => size_of_in_element_count/functions.rs} (71%) rename tests/ui/{size_of_in_element_count.stderr => size_of_in_element_count/functions.stderr} (75%) diff --git a/tests/ui/size_of_in_element_count/expressions.rs b/tests/ui/size_of_in_element_count/expressions.rs new file mode 100644 index 000000000000..b56910917ba8 --- /dev/null +++ b/tests/ui/size_of_in_element_count/expressions.rs @@ -0,0 +1,28 @@ +#![warn(clippy::size_of_in_element_count)] +#![allow(clippy::ptr_offset_with_cast)] + +use std::mem::{size_of, size_of_val}; +use std::ptr::{copy, copy_nonoverlapping, write_bytes}; + +fn main() { + const SIZE: usize = 128; + const HALF_SIZE: usize = SIZE / 2; + const DOUBLE_SIZE: usize = SIZE * 2; + let mut x = [2u8; SIZE]; + let mut y = [2u8; SIZE]; + + // Count expression involving multiplication of size_of (Should trigger the lint) + unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::() * SIZE) }; + + // Count expression involving nested multiplications of size_of (Should trigger the lint) + unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) }; + + // Count expression involving divisions of size_of (Should trigger the lint) + unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() / 2) }; + + // No size_of calls (Should not trigger the lint) + unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) }; + + // Different types for pointee and size_of (Should not trigger the lint) + unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::() / 2 * SIZE) }; +} diff --git a/tests/ui/size_of_in_element_count/expressions.stderr b/tests/ui/size_of_in_element_count/expressions.stderr new file mode 100644 index 000000000000..47b98e9d9474 --- /dev/null +++ b/tests/ui/size_of_in_element_count/expressions.stderr @@ -0,0 +1,27 @@ +error: found a count of bytes instead of a count of elements of `T` + --> $DIR/expressions.rs:15:62 + | +LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::() * SIZE) }; + | ^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `-D clippy::size-of-in-element-count` implied by `-D warnings` + = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type + +error: found a count of bytes instead of a count of elements of `T` + --> $DIR/expressions.rs:18:62 + | +LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type + +error: found a count of bytes instead of a count of elements of `T` + --> $DIR/expressions.rs:21:47 + | +LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() / 2) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type + +error: aborting due to 3 previous errors + diff --git a/tests/ui/size_of_in_element_count.rs b/tests/ui/size_of_in_element_count/functions.rs similarity index 71% rename from tests/ui/size_of_in_element_count.rs rename to tests/ui/size_of_in_element_count/functions.rs index b13e390705ab..09d08ac37dce 100644 --- a/tests/ui/size_of_in_element_count.rs +++ b/tests/ui/size_of_in_element_count/functions.rs @@ -43,19 +43,4 @@ fn main() { y.as_mut_ptr().wrapping_add(size_of::()); unsafe { y.as_ptr().offset(size_of::() as isize) }; y.as_mut_ptr().wrapping_offset(size_of::() as isize); - - // Count expression involving multiplication of size_of (Should trigger the lint) - unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::() * SIZE) }; - - // Count expression involving nested multiplications of size_of (Should trigger the lint) - unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) }; - - // Count expression involving divisions of size_of (Should trigger the lint) - unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() / 2) }; - - // No size_of calls (Should not trigger the lint) - unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) }; - - // Different types for pointee and size_of (Should not trigger the lint) - unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::() / 2 * SIZE) }; } diff --git a/tests/ui/size_of_in_element_count.stderr b/tests/ui/size_of_in_element_count/functions.stderr similarity index 75% rename from tests/ui/size_of_in_element_count.stderr rename to tests/ui/size_of_in_element_count/functions.stderr index 8cf3612abda3..c1e824167b7f 100644 --- a/tests/ui/size_of_in_element_count.stderr +++ b/tests/ui/size_of_in_element_count/functions.stderr @@ -1,5 +1,5 @@ error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:18:68 + --> $DIR/functions.rs:18:68 | LL | unsafe { copy_nonoverlapping::(x.as_ptr(), y.as_mut_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -8,7 +8,7 @@ LL | unsafe { copy_nonoverlapping::(x.as_ptr(), y.as_mut_ptr(), size_of: = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:19:62 + --> $DIR/functions.rs:19:62 | LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) }; | ^^^^^^^^^^^^^^^^^^ @@ -16,7 +16,7 @@ LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:21:49 + --> $DIR/functions.rs:21:49 | LL | unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -24,7 +24,7 @@ LL | unsafe { x.as_ptr().copy_to(y.as_mut_ptr(), size_of::()) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:22:64 + --> $DIR/functions.rs:22:64 | LL | unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -32,7 +32,7 @@ LL | unsafe { x.as_ptr().copy_to_nonoverlapping(y.as_mut_ptr(), size_of:: $DIR/size_of_in_element_count.rs:23:51 + --> $DIR/functions.rs:23:51 | LL | unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -40,7 +40,7 @@ LL | unsafe { y.as_mut_ptr().copy_from(x.as_ptr(), size_of::()) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:24:66 + --> $DIR/functions.rs:24:66 | LL | unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -48,7 +48,7 @@ LL | unsafe { y.as_mut_ptr().copy_from_nonoverlapping(x.as_ptr(), size_of::< = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:26:47 + --> $DIR/functions.rs:26:47 | LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -56,7 +56,7 @@ LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::()) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:27:47 + --> $DIR/functions.rs:27:47 | LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) }; | ^^^^^^^^^^^^^^^^^^ @@ -64,7 +64,7 @@ LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:29:46 + --> $DIR/functions.rs:29:46 | LL | unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::() * SIZE) }; | ^^^^^^^^^^^^^^^^^^^^^^ @@ -72,7 +72,7 @@ LL | unsafe { y.as_mut_ptr().write_bytes(0u8, size_of::() * SIZE) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:30:47 + --> $DIR/functions.rs:30:47 | LL | unsafe { write_bytes(y.as_mut_ptr(), 0u8, size_of::() * SIZE) }; | ^^^^^^^^^^^^^^^^^^^^^^ @@ -80,7 +80,7 @@ LL | unsafe { write_bytes(y.as_mut_ptr(), 0u8, size_of::() * SIZE) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:32:66 + --> $DIR/functions.rs:32:66 | LL | unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::() * SIZE) }; | ^^^^^^^^^^^^^^^^^^^^^^ @@ -88,7 +88,7 @@ LL | unsafe { swap_nonoverlapping(y.as_mut_ptr(), x.as_mut_ptr(), size_of::< = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:34:46 + --> $DIR/functions.rs:34:46 | LL | slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::() * SIZE); | ^^^^^^^^^^^^^^^^^^^^^^ @@ -96,7 +96,7 @@ LL | slice_from_raw_parts_mut(y.as_mut_ptr(), size_of::() * SIZE); = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:35:38 + --> $DIR/functions.rs:35:38 | LL | slice_from_raw_parts(y.as_ptr(), size_of::() * SIZE); | ^^^^^^^^^^^^^^^^^^^^^^ @@ -104,7 +104,7 @@ LL | slice_from_raw_parts(y.as_ptr(), size_of::() * SIZE); = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:37:49 + --> $DIR/functions.rs:37:49 | LL | unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::() * SIZE) }; | ^^^^^^^^^^^^^^^^^^^^^^ @@ -112,7 +112,7 @@ LL | unsafe { from_raw_parts_mut(y.as_mut_ptr(), size_of::() * SIZE) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:38:41 + --> $DIR/functions.rs:38:41 | LL | unsafe { from_raw_parts(y.as_ptr(), size_of::() * SIZE) }; | ^^^^^^^^^^^^^^^^^^^^^^ @@ -120,7 +120,7 @@ LL | unsafe { from_raw_parts(y.as_ptr(), size_of::() * SIZE) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:40:33 + --> $DIR/functions.rs:40:33 | LL | unsafe { y.as_mut_ptr().sub(size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -128,7 +128,7 @@ LL | unsafe { y.as_mut_ptr().sub(size_of::()) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:41:29 + --> $DIR/functions.rs:41:29 | LL | y.as_ptr().wrapping_sub(size_of::()); | ^^^^^^^^^^^^^^^ @@ -136,7 +136,7 @@ LL | y.as_ptr().wrapping_sub(size_of::()); = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:42:29 + --> $DIR/functions.rs:42:29 | LL | unsafe { y.as_ptr().add(size_of::()) }; | ^^^^^^^^^^^^^^^ @@ -144,7 +144,7 @@ LL | unsafe { y.as_ptr().add(size_of::()) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:43:33 + --> $DIR/functions.rs:43:33 | LL | y.as_mut_ptr().wrapping_add(size_of::()); | ^^^^^^^^^^^^^^^ @@ -152,7 +152,7 @@ LL | y.as_mut_ptr().wrapping_add(size_of::()); = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:44:32 + --> $DIR/functions.rs:44:32 | LL | unsafe { y.as_ptr().offset(size_of::() as isize) }; | ^^^^^^^^^^^^^^^^^^^^^^^^ @@ -160,36 +160,12 @@ LL | unsafe { y.as_ptr().offset(size_of::() as isize) }; = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:45:36 + --> $DIR/functions.rs:45:36 | LL | y.as_mut_ptr().wrapping_offset(size_of::() as isize); | ^^^^^^^^^^^^^^^^^^^^^^^^ | = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type -error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:48:62 - | -LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::() * SIZE) }; - | ^^^^^^^^^^^^^^^^^^^^^^ - | - = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type - -error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:51:62 - | -LL | unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) }; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | - = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type - -error: found a count of bytes instead of a count of elements of `T` - --> $DIR/size_of_in_element_count.rs:54:47 - | -LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() / 2) }; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | - = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type - -error: aborting due to 24 previous errors +error: aborting due to 21 previous errors From d4bf59b6ef24042653951b69105a3a68542f3bbd Mon Sep 17 00:00:00 2001 From: Marijn Suijten Date: Tue, 12 Jan 2021 11:35:44 +0100 Subject: [PATCH 2/2] size_of_in_element_count: Disable lint on division by byte-size It is fairly common to divide some length in bytes by the byte-size of a single element before creating a `from_raw_parts` slice or similar operation. This lint would erroneously disallow such expressions. Just in case, instead of simply disabling this lint in the RHS of a division, keep track of the inversion and enable it again on recursive division. --- clippy_lints/src/size_of_in_element_count.rs | 14 +++++++++----- tests/ui/size_of_in_element_count/expressions.rs | 9 +++++++++ .../ui/size_of_in_element_count/expressions.stderr | 10 +++++++++- 3 files changed, 27 insertions(+), 6 deletions(-) diff --git a/clippy_lints/src/size_of_in_element_count.rs b/clippy_lints/src/size_of_in_element_count.rs index ea7a76146f52..87e386baadc5 100644 --- a/clippy_lints/src/size_of_in_element_count.rs +++ b/clippy_lints/src/size_of_in_element_count.rs @@ -35,10 +35,11 @@ declare_clippy_lint! { declare_lint_pass!(SizeOfInElementCount => [SIZE_OF_IN_ELEMENT_COUNT]); -fn get_size_of_ty(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option> { +fn get_size_of_ty(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, inverted: bool) -> Option> { match expr.kind { ExprKind::Call(count_func, _func_args) => { if_chain! { + if !inverted; if let ExprKind::Path(ref count_func_qpath) = count_func.kind; if let Some(def_id) = cx.qpath_res(count_func_qpath, count_func.hir_id).opt_def_id(); if match_def_path(cx, def_id, &paths::MEM_SIZE_OF) @@ -50,10 +51,13 @@ fn get_size_of_ty(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option { - get_size_of_ty(cx, left).or_else(|| get_size_of_ty(cx, right)) + ExprKind::Binary(op, left, right) if BinOpKind::Mul == op.node => { + get_size_of_ty(cx, left, inverted).or_else(|| get_size_of_ty(cx, right, inverted)) }, - ExprKind::Cast(expr, _) => get_size_of_ty(cx, expr), + ExprKind::Binary(op, left, right) if BinOpKind::Div == op.node => { + get_size_of_ty(cx, left, inverted).or_else(|| get_size_of_ty(cx, right, !inverted)) + }, + ExprKind::Cast(expr, _) => get_size_of_ty(cx, expr, inverted), _ => None, } } @@ -128,7 +132,7 @@ impl<'tcx> LateLintPass<'tcx> for SizeOfInElementCount { // Find a size_of call in the count parameter expression and // check that it's the same type - if let Some(ty_used_for_size_of) = get_size_of_ty(cx, count_expr); + if let Some(ty_used_for_size_of) = get_size_of_ty(cx, count_expr, false); if TyS::same_type(pointee_ty, ty_used_for_size_of); then { span_lint_and_help( diff --git a/tests/ui/size_of_in_element_count/expressions.rs b/tests/ui/size_of_in_element_count/expressions.rs index b56910917ba8..2594e8fa6ad3 100644 --- a/tests/ui/size_of_in_element_count/expressions.rs +++ b/tests/ui/size_of_in_element_count/expressions.rs @@ -20,6 +20,15 @@ fn main() { // Count expression involving divisions of size_of (Should trigger the lint) unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() / 2) }; + // Count expression involving divisions by size_of (Should not trigger the lint) + unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / size_of::()) }; + + // Count expression involving divisions by multiple size_of (Should not trigger the lint) + unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 * size_of::())) }; + + // Count expression involving recursive divisions by size_of (Should trigger the lint) + unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::())) }; + // No size_of calls (Should not trigger the lint) unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) }; diff --git a/tests/ui/size_of_in_element_count/expressions.stderr b/tests/ui/size_of_in_element_count/expressions.stderr index 47b98e9d9474..0f0dff57f51b 100644 --- a/tests/ui/size_of_in_element_count/expressions.stderr +++ b/tests/ui/size_of_in_element_count/expressions.stderr @@ -23,5 +23,13 @@ LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::() | = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type -error: aborting due to 3 previous errors +error: found a count of bytes instead of a count of elements of `T` + --> $DIR/expressions.rs:30:47 + | +LL | unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / (2 / size_of::())) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: use a count of elements instead of a count of bytes, it already gets multiplied by the size of the type + +error: aborting due to 4 previous errors