Rollup merge of rust-lang#85555 - LeSeulArtichaut:thir-unsafeck, r=ni…

…komatsakis

Check for more things in THIR unsafeck

Reunion of rust-lang#85306, rust-lang#85381 and rust-lang#85419 with conflicts resolved.
r? `@nikomatsakis`

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -7,8 +7,11 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::builtin::{UNSAFE_OP_IN_UNSAFE_FN, UNUSED_UNSAFE};
 use rustc_session::lint::Level;
 use rustc_span::def_id::{DefId, LocalDefId};
+use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 
+use std::ops::Bound;
+
 struct UnsafetyVisitor<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     thir: &'a Thir<'tcx>,
@@ -19,6 +22,10 @@ struct UnsafetyVisitor<'a, 'tcx> {
     /// `unsafe` block, and whether it has been used.
     safety_context: SafetyContext,
     body_unsafety: BodyUnsafety,
+    /// The `#[target_feature]` attributes of the body. Used for checking
+    /// calls to functions with `#[target_feature]` (RFC 2396).
+    body_target_features: &'tcx Vec<Symbol>,
+    is_const: bool,
 }
 
 impl<'tcx> UnsafetyVisitor<'_, 'tcx> {
@@ -148,11 +155,55 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             ExprKind::Call { fun, ty: _, args: _, from_hir_call: _, fn_span: _ } => {
                 if self.thir[fun].ty.fn_sig(self.tcx).unsafety() == hir::Unsafety::Unsafe {
                     self.requires_unsafe(expr.span, CallToUnsafeFunction);
+                } else if let &ty::FnDef(func_did, _) = self.thir[fun].ty.kind() {
+                    // If the called function has target features the calling function hasn't,
+                    // the call requires `unsafe`.
+                    if !self
+                        .tcx
+                        .codegen_fn_attrs(func_did)
+                        .target_features
+                        .iter()
+                        .all(|feature| self.body_target_features.contains(feature))
+                    {
+                        self.requires_unsafe(expr.span, CallToFunctionWith);
+                    }
+                }
+            }
+            ExprKind::Deref { arg } => {
+                if let ExprKind::StaticRef { def_id, .. } = self.thir[arg].kind {
+                    if self.tcx.is_mutable_static(def_id) {
+                        self.requires_unsafe(expr.span, UseOfMutableStatic);
+                    } else if self.tcx.is_foreign_item(def_id) {
+                        self.requires_unsafe(expr.span, UseOfExternStatic);
+                    }
+                } else if self.thir[arg].ty.is_unsafe_ptr() {
+                    self.requires_unsafe(expr.span, DerefOfRawPointer);
                 }
             }
             ExprKind::InlineAsm { .. } | ExprKind::LlvmInlineAsm { .. } => {
                 self.requires_unsafe(expr.span, UseOfInlineAssembly);
             }
+            ExprKind::Adt {
+                adt_def,
+                variant_index: _,
+                substs: _,
+                user_ty: _,
+                fields: _,
+                base: _,
+            } => match self.tcx.layout_scalar_valid_range(adt_def.did) {
+                (Bound::Unbounded, Bound::Unbounded) => {}
+                _ => self.requires_unsafe(expr.span, InitializingTypeWith),
+            },
+            ExprKind::Cast { source } => {
+                let source = &self.thir[source];
+                if self.tcx.features().const_raw_ptr_to_usize_cast
+                    && self.is_const
+                    && (source.ty.is_unsafe_ptr() || source.ty.is_fn_ptr())
+                    && expr.ty.is_integral()
+                {
+                    self.requires_unsafe(expr.span, CastOfPointerToInt);
+                }
+            }
             _ => {}
         }
 
@@ -195,15 +246,10 @@ impl BodyUnsafety {
 enum UnsafeOpKind {
     CallToUnsafeFunction,
     UseOfInlineAssembly,
-    #[allow(dead_code)] // FIXME
     InitializingTypeWith,
-    #[allow(dead_code)] // FIXME
     CastOfPointerToInt,
-    #[allow(dead_code)] // FIXME
     UseOfMutableStatic,
-    #[allow(dead_code)] // FIXME
     UseOfExternStatic,
-    #[allow(dead_code)] // FIXME
     DerefOfRawPointer,
     #[allow(dead_code)] // FIXME
     AssignToDroppingUnionField,
@@ -213,7 +259,6 @@ enum UnsafeOpKind {
     MutationOfLayoutConstrainedField,
     #[allow(dead_code)] // FIXME
     BorrowOfLayoutConstrainedField,
-    #[allow(dead_code)] // FIXME
     CallToFunctionWith,
 }
 
@@ -287,6 +332,7 @@ pub fn check_unsafety<'tcx>(
     tcx: TyCtxt<'tcx>,
     thir: &Thir<'tcx>,
     expr: ExprId,
+    def_id: LocalDefId,
     hir_id: hir::HirId,
 ) {
     let body_unsafety = tcx.hir().fn_sig_by_hir_id(hir_id).map_or(BodyUnsafety::Safe, |fn_sig| {
@@ -296,10 +342,23 @@ pub fn check_unsafety<'tcx>(
             BodyUnsafety::Safe
         }
     });
+    let body_target_features = &tcx.codegen_fn_attrs(def_id).target_features;
     let safety_context =
         if body_unsafety.is_unsafe() { SafetyContext::UnsafeFn } else { SafetyContext::Safe };
-    let mut visitor =
-        UnsafetyVisitor { tcx, thir, safety_context, hir_context: hir_id, body_unsafety };
+    let is_const = match tcx.hir().body_owner_kind(hir_id) {
+        hir::BodyOwnerKind::Closure => false,
+        hir::BodyOwnerKind::Fn => tcx.is_const_fn_raw(def_id.to_def_id()),
+        hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => true,
+    };
+    let mut visitor = UnsafetyVisitor {
+        tcx,
+        thir,
+        safety_context,
+        hir_context: hir_id,
+        body_unsafety,
+        body_target_features,
+        is_const,
+    };
     visitor.visit_expr(&thir[expr]);
 }
 
@@ -311,7 +370,7 @@ crate fn thir_check_unsafety_inner<'tcx>(
     let body_id = tcx.hir().body_owned_by(hir_id);
     let body = tcx.hir().body(body_id);
     let (thir, expr) = cx::build_thir(tcx, def, &body.value);
-    check_unsafety(tcx, &thir, expr, hir_id);
+    check_unsafety(tcx, &thir, expr, def.did, hir_id);
 }
 
 crate fn thir_check_unsafety<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) {

src/test/ui/cast/cast-ptr-to-int-const.mir.stderr

@@ -0,0 +1,19 @@
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:10:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:17:5
+   |
+LL |     &0 as *const i32 as usize
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0133`.

src/test/ui/cast/cast-ptr-to-int-const.rs

@@ -1,25 +1,19 @@
-// gate-test-const_raw_ptr_to_usize_cast
-// revisions: with_feature without_feature
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
 
-#![cfg_attr(with_feature, feature(const_raw_ptr_to_usize_cast))]
+#![feature(const_raw_ptr_to_usize_cast)]
 
 fn main() {
-    const X: usize = unsafe {
-        main as usize //[without_feature]~ ERROR casting pointers to integers in constants is unstable
-    };
     const Y: u32 = 0;
-    const Z: usize = unsafe {
-        &Y as *const u32 as usize //[without_feature]~ ERROR is unstable
-    };
     // Cast in `const` without `unsafe` block
     const SAFE: usize = {
-        &Y as *const u32 as usize //[without_feature]~ ERROR is unstable
-        //[with_feature]~^ ERROR cast of pointer to int is unsafe and requires unsafe
+        &Y as *const u32 as usize
+        //~^ ERROR cast of pointer to int is unsafe and requires unsafe
     };
 }
 
 // Cast in `const fn` without `unsafe` block
 const fn test() -> usize {
-    &0 as *const i32 as usize //[without_feature]~ ERROR is unstable
-    //[with_feature]~^ ERROR cast of pointer to int is unsafe and requires unsafe
+    &0 as *const i32 as usize
+    //~^ ERROR cast of pointer to int is unsafe and requires unsafe
 }

src/test/ui/cast/cast-ptr-to-int-const.thir.stderr

@@ -0,0 +1,19 @@
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:10:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error[E0133]: cast of pointer to int is unsafe and requires unsafe function or block
+  --> $DIR/cast-ptr-to-int-const.rs:17:5
+   |
+LL |     &0 as *const i32 as usize
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cast of pointer to int
+   |
+   = note: casting pointers to integers in constants
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0133`.

src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.rs

@@ -0,0 +1,13 @@
+fn main() {
+    const X: usize = unsafe {
+        main as usize //~ ERROR casting pointers to integers in constants is unstable
+    };
+    const Y: u32 = 0;
+    const Z: usize = unsafe {
+        &Y as *const u32 as usize //~ ERROR is unstable
+    };
+}
+
+const fn test() -> usize {
+    &0 as *const i32 as usize //~ ERROR is unstable
+}

src/test/ui/cast/feature-gate-const_raw_ptr_to_usize_cast.stderr

@@ -0,0 +1,30 @@
+error[E0658]: casting pointers to integers in constants is unstable
+  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:3:9
+   |
+LL |         main as usize
+   |         ^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error[E0658]: casting pointers to integers in constants is unstable
+  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:7:9
+   |
+LL |         &Y as *const u32 as usize
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error[E0658]: casting pointers to integers in constant functions is unstable
+  --> $DIR/feature-gate-const_raw_ptr_to_usize_cast.rs:12:5
+   |
+LL |     &0 as *const i32 as usize
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #51910 <https://github.com/rust-lang/rust/issues/51910> for more information
+   = help: add `#![feature(const_raw_ptr_to_usize_cast)]` to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/generator/issue-45729-unsafe-in-generator.stderr → src/test/ui/generator/issue-45729-unsafe-in-generator.mir.stderr

@@ -1,5 +1,5 @@
 error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
-  --> $DIR/issue-45729-unsafe-in-generator.rs:5:9
+  --> $DIR/issue-45729-unsafe-in-generator.rs:8:9
    |
 LL |         *(1 as *mut u32) = 42;
    |         ^^^^^^^^^^^^^^^^^^^^^ dereference of raw pointer

src/test/ui/generator/issue-45729-unsafe-in-generator.rs

@@ -1,3 +1,6 @@
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
 #![feature(generators)]
 
 fn main() {

src/test/ui/generator/issue-45729-unsafe-in-generator.thir.stderr

@@ -0,0 +1,11 @@
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/issue-45729-unsafe-in-generator.rs:8:9
+   |
+LL |         *(1 as *mut u32) = 42;
+   |         ^^^^^^^^^^^^^^^^ dereference of raw pointer
+   |
+   = note: raw pointers may be NULL, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0133`.

src/test/ui/intrinsics/issue-28575.stderr → src/test/ui/intrinsics/issue-28575.mir.stderr

@@ -1,5 +1,5 @@
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/issue-28575.rs:8:5
+  --> $DIR/issue-28575.rs:11:5
    |
 LL |     FOO()
    |     ^^^ use of extern static

src/test/ui/intrinsics/issue-28575.rs

@@ -1,3 +1,6 @@
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
 #![feature(intrinsics)]
 
 extern "C" {

src/test/ui/intrinsics/issue-28575.thir.stderr

@@ -0,0 +1,11 @@
+error[E0133]: use of extern static is unsafe and requires unsafe function or block
+  --> $DIR/issue-28575.rs:11:5
+   |
+LL |     FOO()
+   |     ^^^ use of extern static
+   |
+   = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0133`.

src/test/ui/issues/issue-14227.stderr → src/test/ui/issues/issue-14227.mir.stderr

@@ -1,5 +1,5 @@
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/issue-14227.rs:4:21
+  --> $DIR/issue-14227.rs:7:21
    |
 LL | static CRASH: u32 = symbol;
    |                     ^^^^^^ use of extern static

src/test/ui/issues/issue-14227.rs

@@ -1,3 +1,6 @@
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
 extern "C" {
     pub static symbol: u32;
 }

src/test/ui/issues/issue-14227.thir.stderr

@@ -0,0 +1,11 @@
+error[E0133]: use of extern static is unsafe and requires unsafe function or block
+  --> $DIR/issue-14227.rs:7:21
+   |
+LL | static CRASH: u32 = symbol;
+   |                     ^^^^^^ use of extern static
+   |
+   = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0133`.

src/test/ui/issues/issue-16538.stderr → src/test/ui/issues/issue-16538.mir.stderr

@@ -1,11 +1,11 @@
 error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
-  --> $DIR/issue-16538.rs:11:27
+  --> $DIR/issue-16538.rs:14:27
    |
 LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `*const usize` cannot be shared between threads safely
-  --> $DIR/issue-16538.rs:11:1
+  --> $DIR/issue-16538.rs:14:1
    |
 LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const usize` cannot be shared between threads safely
@@ -14,7 +14,7 @@ LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
    = note: shared static variables must have a type that implements `Sync`
 
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/issue-16538.rs:11:34
+  --> $DIR/issue-16538.rs:14:34
    |
 LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
    |                                  ^^^^ use of extern static

src/test/ui/issues/issue-16538.rs

@@ -1,3 +1,6 @@
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
 mod Y {
     pub type X = usize;
     extern "C" {

src/test/ui/issues/issue-16538.thir.stderr

@@ -0,0 +1,27 @@
+error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
+  --> $DIR/issue-16538.rs:14:27
+   |
+LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: `*const usize` cannot be shared between threads safely
+  --> $DIR/issue-16538.rs:14:1
+   |
+LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const usize` cannot be shared between threads safely
+   |
+   = help: the trait `Sync` is not implemented for `*const usize`
+   = note: shared static variables must have a type that implements `Sync`
+
+error[E0133]: use of extern static is unsafe and requires unsafe function or block
+  --> $DIR/issue-16538.rs:14:34
+   |
+LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
+   |                                  ^^^^ use of extern static
+   |
+   = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0015, E0133, E0277.
+For more information about an error, try `rustc --explain E0015`.