From: Ralf Jung Date: Sat, 17 Aug 2019 09:48:30 +0000 (+0200) Subject: invalid_value: also detect transmute-from-0 (seen in the wild) X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=a9efa738ab4e9517a86314f5c0787efef7d8e2a9;p=rust.git invalid_value: also detect transmute-from-0 (seen in the wild) --- diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs index 74cff1bab0f..877dc43fb7b 100644 --- a/src/librustc_lint/builtin.rs +++ b/src/librustc_lint/builtin.rs @@ -1879,12 +1879,38 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &hir::Expr) { #[derive(Debug, Copy, Clone, PartialEq)] enum InitKind { Zeroed, Uninit }; + /// Information about why a type cannot be initialized this way. + /// Contains an error message and optionally a span to point at. + type InitError = (String, Option); + + /// Test if this constant is all-0. + fn is_zero(expr: &hir::Expr) -> bool { + use hir::ExprKind::*; + use syntax::ast::LitKind::*; + match &expr.node { + Lit(lit) => + if let Int(i, _) = lit.node { + i == 0 + } else { + false + }, + Tup(tup) => + tup.iter().all(is_zero), + _ => + false + } + } + /// Determine if this expression is a "dangerous initialization". fn is_dangerous_init(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> Option { const ZEROED_PATH: &[Symbol] = &[sym::core, sym::mem, sym::zeroed]; const UININIT_PATH: &[Symbol] = &[sym::core, sym::mem, sym::uninitialized]; + // `transmute` is inside an anonymous module (the `extern` block?); + // `Invalid` represents the empty string and matches that. + const TRANSMUTE_PATH: &[Symbol] = + &[sym::core, sym::intrinsics, kw::Invalid, sym::transmute]; - if let hir::ExprKind::Call(ref path_expr, ref _args) = expr.node { + if let hir::ExprKind::Call(ref path_expr, ref args) = expr.node { if let hir::ExprKind::Path(ref qpath) = path_expr.node { if let Some(def_id) = cx.tables.qpath_res(qpath, path_expr.hir_id) .opt_def_id() @@ -1895,9 +1921,13 @@ fn is_dangerous_init(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> Option, expr: &hir::Expr) -> Option); - /// Return `Some` only if we are sure this type does *not* /// allow zero initialization. fn ty_find_init_error<'tcx>( diff --git a/src/test/ui/lint/uninitialized-zeroed.rs b/src/test/ui/lint/uninitialized-zeroed.rs index 237f2c0141d..54e1210768c 100644 --- a/src/test/ui/lint/uninitialized-zeroed.rs +++ b/src/test/ui/lint/uninitialized-zeroed.rs @@ -7,6 +7,7 @@ #![deny(invalid_value)] use std::mem::{self, MaybeUninit}; +use std::num::NonZeroU32; enum Void {} @@ -75,6 +76,11 @@ fn main() { let _val: NonBig = mem::zeroed(); let _val: NonBig = mem::uninitialized(); //~ ERROR: does not permit being left uninitialized + // Transmute-from-0 + let _val: &'static i32 = mem::transmute(0usize); //~ ERROR: does not permit zero-initialization + let _val: &'static [i32] = mem::transmute((0usize, 0usize)); //~ ERROR: does not permit zero-initialization + let _val: NonZeroU32 = mem::transmute(0); //~ ERROR: does not permit zero-initialization + // Some more types that should work just fine. let _val: Option<&'static i32> = mem::zeroed(); let _val: Option = mem::zeroed(); diff --git a/src/test/ui/lint/uninitialized-zeroed.stderr b/src/test/ui/lint/uninitialized-zeroed.stderr index c5006345e52..90a51ba57e9 100644 --- a/src/test/ui/lint/uninitialized-zeroed.stderr +++ b/src/test/ui/lint/uninitialized-zeroed.stderr @@ -1,5 +1,5 @@ error: the type `&'static T` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:27:32 + --> $DIR/uninitialized-zeroed.rs:28:32 | LL | let _val: &'static T = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -15,7 +15,7 @@ LL | #![deny(invalid_value)] = note: References must be non-null error: the type `&'static T` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:28:32 + --> $DIR/uninitialized-zeroed.rs:29:32 | LL | let _val: &'static T = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -26,7 +26,7 @@ LL | let _val: &'static T = mem::uninitialized(); = note: References must be non-null error: the type `Wrap<&'static T>` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:30:38 + --> $DIR/uninitialized-zeroed.rs:31:38 | LL | let _val: Wrap<&'static T> = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -35,13 +35,13 @@ LL | let _val: Wrap<&'static T> = mem::zeroed(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:16:18 + --> $DIR/uninitialized-zeroed.rs:17:18 | LL | struct Wrap { wrapped: T } | ^^^^^^^^^^ error: the type `Wrap<&'static T>` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:31:38 + --> $DIR/uninitialized-zeroed.rs:32:38 | LL | let _val: Wrap<&'static T> = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -50,13 +50,13 @@ LL | let _val: Wrap<&'static T> = mem::uninitialized(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:16:18 + --> $DIR/uninitialized-zeroed.rs:17:18 | LL | struct Wrap { wrapped: T } | ^^^^^^^^^^ error: the type `!` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:38:23 + --> $DIR/uninitialized-zeroed.rs:39:23 | LL | let _val: ! = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -67,7 +67,7 @@ LL | let _val: ! = mem::zeroed(); = note: The never type (`!`) has no valid value error: the type `!` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:39:23 + --> $DIR/uninitialized-zeroed.rs:40:23 | LL | let _val: ! = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -78,7 +78,7 @@ LL | let _val: ! = mem::uninitialized(); = note: The never type (`!`) has no valid value error: the type `(i32, !)` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:41:30 + --> $DIR/uninitialized-zeroed.rs:42:30 | LL | let _val: (i32, !) = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -89,7 +89,7 @@ LL | let _val: (i32, !) = mem::zeroed(); = note: The never type (`!`) has no valid value error: the type `(i32, !)` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:42:30 + --> $DIR/uninitialized-zeroed.rs:43:30 | LL | let _val: (i32, !) = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -100,7 +100,7 @@ LL | let _val: (i32, !) = mem::uninitialized(); = note: The never type (`!`) has no valid value error: the type `Void` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:44:26 + --> $DIR/uninitialized-zeroed.rs:45:26 | LL | let _val: Void = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -111,7 +111,7 @@ LL | let _val: Void = mem::zeroed(); = note: 0-variant enums have no valid value error: the type `Void` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:45:26 + --> $DIR/uninitialized-zeroed.rs:46:26 | LL | let _val: Void = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -122,7 +122,7 @@ LL | let _val: Void = mem::uninitialized(); = note: 0-variant enums have no valid value error: the type `&'static i32` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:47:34 + --> $DIR/uninitialized-zeroed.rs:48:34 | LL | let _val: &'static i32 = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -133,7 +133,7 @@ LL | let _val: &'static i32 = mem::zeroed(); = note: References must be non-null error: the type `&'static i32` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:48:34 + --> $DIR/uninitialized-zeroed.rs:49:34 | LL | let _val: &'static i32 = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -144,7 +144,7 @@ LL | let _val: &'static i32 = mem::uninitialized(); = note: References must be non-null error: the type `Ref` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:50:25 + --> $DIR/uninitialized-zeroed.rs:51:25 | LL | let _val: Ref = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -153,13 +153,13 @@ LL | let _val: Ref = mem::zeroed(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:13:12 + --> $DIR/uninitialized-zeroed.rs:14:12 | LL | struct Ref(&'static i32); | ^^^^^^^^^^^^ error: the type `Ref` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:51:25 + --> $DIR/uninitialized-zeroed.rs:52:25 | LL | let _val: Ref = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -168,13 +168,13 @@ LL | let _val: Ref = mem::uninitialized(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:13:12 + --> $DIR/uninitialized-zeroed.rs:14:12 | LL | struct Ref(&'static i32); | ^^^^^^^^^^^^ error: the type `fn()` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:53:26 + --> $DIR/uninitialized-zeroed.rs:54:26 | LL | let _val: fn() = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -185,7 +185,7 @@ LL | let _val: fn() = mem::zeroed(); = note: Function pointers must be non-null error: the type `fn()` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:54:26 + --> $DIR/uninitialized-zeroed.rs:55:26 | LL | let _val: fn() = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -196,7 +196,7 @@ LL | let _val: fn() = mem::uninitialized(); = note: Function pointers must be non-null error: the type `Wrap` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:56:32 + --> $DIR/uninitialized-zeroed.rs:57:32 | LL | let _val: Wrap = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -205,13 +205,13 @@ LL | let _val: Wrap = mem::zeroed(); | help: use `MaybeUninit` instead | note: Function pointers must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:16:18 + --> $DIR/uninitialized-zeroed.rs:17:18 | LL | struct Wrap { wrapped: T } | ^^^^^^^^^^ error: the type `Wrap` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:57:32 + --> $DIR/uninitialized-zeroed.rs:58:32 | LL | let _val: Wrap = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -220,13 +220,13 @@ LL | let _val: Wrap = mem::uninitialized(); | help: use `MaybeUninit` instead | note: Function pointers must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:16:18 + --> $DIR/uninitialized-zeroed.rs:17:18 | LL | struct Wrap { wrapped: T } | ^^^^^^^^^^ error: the type `WrapEnum` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:59:36 + --> $DIR/uninitialized-zeroed.rs:60:36 | LL | let _val: WrapEnum = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -235,13 +235,13 @@ LL | let _val: WrapEnum = mem::zeroed(); | help: use `MaybeUninit` instead | note: Function pointers must be non-null (in this enum field) - --> $DIR/uninitialized-zeroed.rs:17:28 + --> $DIR/uninitialized-zeroed.rs:18:28 | LL | enum WrapEnum { Wrapped(T) } | ^ error: the type `WrapEnum` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:60:36 + --> $DIR/uninitialized-zeroed.rs:61:36 | LL | let _val: WrapEnum = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -250,13 +250,13 @@ LL | let _val: WrapEnum = mem::uninitialized(); | help: use `MaybeUninit` instead | note: Function pointers must be non-null (in this enum field) - --> $DIR/uninitialized-zeroed.rs:17:28 + --> $DIR/uninitialized-zeroed.rs:18:28 | LL | enum WrapEnum { Wrapped(T) } | ^ error: the type `Wrap<(RefPair, i32)>` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:62:42 + --> $DIR/uninitialized-zeroed.rs:63:42 | LL | let _val: Wrap<(RefPair, i32)> = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -265,13 +265,13 @@ LL | let _val: Wrap<(RefPair, i32)> = mem::zeroed(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:14:16 + --> $DIR/uninitialized-zeroed.rs:15:16 | LL | struct RefPair((&'static i32, i32)); | ^^^^^^^^^^^^^^^^^^^ error: the type `Wrap<(RefPair, i32)>` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:63:42 + --> $DIR/uninitialized-zeroed.rs:64:42 | LL | let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -280,13 +280,13 @@ LL | let _val: Wrap<(RefPair, i32)> = mem::uninitialized(); | help: use `MaybeUninit` instead | note: References must be non-null (in this struct field) - --> $DIR/uninitialized-zeroed.rs:14:16 + --> $DIR/uninitialized-zeroed.rs:15:16 | LL | struct RefPair((&'static i32, i32)); | ^^^^^^^^^^^^^^^^^^^ error: the type `std::vec::Vec` does not permit zero-initialization - --> $DIR/uninitialized-zeroed.rs:65:30 + --> $DIR/uninitialized-zeroed.rs:66:30 | LL | let _val: Vec = mem::zeroed(); | ^^^^^^^^^^^^^ @@ -301,7 +301,7 @@ LL | ptr: Unique, | ^^^^^^^^^^^^^^ error: the type `std::vec::Vec` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:66:30 + --> $DIR/uninitialized-zeroed.rs:67:30 | LL | let _val: Vec = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -316,7 +316,7 @@ LL | ptr: Unique, | ^^^^^^^^^^^^^^ error: the type `bool` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:70:26 + --> $DIR/uninitialized-zeroed.rs:71:26 | LL | let _val: bool = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -327,7 +327,7 @@ LL | let _val: bool = mem::uninitialized(); = note: Booleans must be `true` or `false` error: the type `Wrap` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:73:32 + --> $DIR/uninitialized-zeroed.rs:74:32 | LL | let _val: Wrap = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -336,13 +336,13 @@ LL | let _val: Wrap = mem::uninitialized(); | help: use `MaybeUninit` instead | note: Characters must be a valid unicode codepoint (in this struct field) - --> $DIR/uninitialized-zeroed.rs:16:18 + --> $DIR/uninitialized-zeroed.rs:17:18 | LL | struct Wrap { wrapped: T } | ^^^^^^^^^^ error: the type `NonBig` does not permit being left uninitialized - --> $DIR/uninitialized-zeroed.rs:76:28 + --> $DIR/uninitialized-zeroed.rs:77:28 | LL | let _val: NonBig = mem::uninitialized(); | ^^^^^^^^^^^^^^^^^^^^ @@ -352,5 +352,38 @@ LL | let _val: NonBig = mem::uninitialized(); | = note: NonBig must be initialized inside its custom valid range -error: aborting due to 27 previous errors +error: the type `&'static i32` does not permit zero-initialization + --> $DIR/uninitialized-zeroed.rs:80:34 + | +LL | let _val: &'static i32 = mem::transmute(0usize); + | ^^^^^^^^^^^^^^^^^^^^^^ + | | + | this code causes undefined behavior when executed + | help: use `MaybeUninit` instead + | + = note: References must be non-null + +error: the type `&'static [i32]` does not permit zero-initialization + --> $DIR/uninitialized-zeroed.rs:81:36 + | +LL | let _val: &'static [i32] = mem::transmute((0usize, 0usize)); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | | + | this code causes undefined behavior when executed + | help: use `MaybeUninit` instead + | + = note: References must be non-null + +error: the type `std::num::NonZeroU32` does not permit zero-initialization + --> $DIR/uninitialized-zeroed.rs:82:32 + | +LL | let _val: NonZeroU32 = mem::transmute(0); + | ^^^^^^^^^^^^^^^^^ + | | + | this code causes undefined behavior when executed + | help: use `MaybeUninit` instead + | + = note: std::num::NonZeroU32 must be non-null + +error: aborting due to 30 previous errors