Auto merge of #125761 - matthiaskrgr:rollup-7u082og, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #125342 (Document platform-specifics for `Read` and `Write` of `File`)
 - #125711 (Make `body_owned_by` return the `Body` instead of just the `BodyId`)
 - #125739 (drop_in_place: weaken the claim of equivalence with drop(ptr.read()))
 - #125745 (Bump the stage0 compiler to beta.7 (2024-05-26))
 - #125746 (Fix copy-paste error in `Duration::from_weeks` panic message.)
 - #125753 (compiletest: Unify `cmd2procres` with `run_command_to_procres`)
 - #125754 (coverage: Rename MC/DC `conditions_num` to `num_conditions`)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_codegen_llvm/src/coverageinfo/ffi.rs

@@ -118,7 +118,7 @@ pub mod mcdc {
     #[derive(Clone, Copy, Debug, Default)]
     pub struct DecisionParameters {
         bitmap_idx: u32,
-        conditions_num: u16,
+        num_conditions: u16,
     }
 
     // ConditionId in llvm is `unsigned int` at 18 while `int16_t` at [19](https://github.com/llvm/llvm-project/pull/81257)
@@ -177,8 +177,9 @@ pub mod mcdc {
     }
 
     impl From<DecisionInfo> for DecisionParameters {
-        fn from(value: DecisionInfo) -> Self {
-            Self { bitmap_idx: value.bitmap_idx, conditions_num: value.conditions_num }
+        fn from(info: DecisionInfo) -> Self {
+            let DecisionInfo { bitmap_idx, num_conditions } = info;
+            Self { bitmap_idx, num_conditions }
         }
     }
 }

compiler/rustc_middle/src/mir/coverage.rs

@@ -329,14 +329,14 @@ pub struct MCDCBranchSpan {
 #[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct DecisionInfo {
     pub bitmap_idx: u32,
-    pub conditions_num: u16,
+    pub num_conditions: u16,
 }
 
 #[derive(Clone, Debug)]
 #[derive(TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct MCDCDecisionSpan {
     pub span: Span,
-    pub conditions_num: usize,
+    pub num_conditions: usize,
     pub end_markers: Vec<BlockMarkerId>,
     pub decision_depth: u16,
 }

compiler/rustc_middle/src/mir/pretty.rs

@@ -512,12 +512,12 @@ fn write_coverage_branch_info(
         )?;
     }
 
-    for coverage::MCDCDecisionSpan { span, conditions_num, end_markers, decision_depth } in
+    for coverage::MCDCDecisionSpan { span, num_conditions, end_markers, decision_depth } in
         mcdc_decision_spans
     {
         writeln!(
             w,
-            "{INDENT}coverage mcdc decision {{ conditions_num: {conditions_num:?}, end: {end_markers:?}, depth: {decision_depth:?} }} => {span:?}"
+            "{INDENT}coverage mcdc decision {{ num_conditions: {num_conditions:?}, end: {end_markers:?}, depth: {decision_depth:?} }} => {span:?}"
         )?;
     }
 

compiler/rustc_mir_build/messages.ftl

@@ -97,7 +97,7 @@ mir_build_deref_raw_pointer_requires_unsafe_unsafe_op_in_unsafe_fn_allowed =
     .note = raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
     .label = dereference of raw pointer
 
-mir_build_exceeds_mcdc_condition_num_limit =  Conditions number of the decision ({$conditions_num}) exceeds limit ({$max_conditions_num}). MCDC analysis will not count this expression.
+mir_build_exceeds_mcdc_condition_limit = Number of conditions in decision ({$num_conditions}) exceeds limit ({$max_conditions}). MC/DC analysis will not count this expression.
 
 mir_build_extern_static_requires_unsafe =
     use of extern static is unsafe and requires unsafe block

compiler/rustc_mir_build/src/build/coverageinfo/mcdc.rs

@@ -10,12 +10,12 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::Span;
 
 use crate::build::Builder;
-use crate::errors::MCDCExceedsConditionNumLimit;
+use crate::errors::MCDCExceedsConditionLimit;
 
 /// The MCDC bitmap scales exponentially (2^n) based on the number of conditions seen,
 /// So llvm sets a maximum value prevents the bitmap footprint from growing too large without the user's knowledge.
 /// This limit may be relaxed if the [upstream change](https://github.com/llvm/llvm-project/pull/82448) is merged.
-const MAX_CONDITIONS_NUM_IN_DECISION: usize = 6;
+const MAX_CONDITIONS_IN_DECISION: usize = 6;
 
 #[derive(Default)]
 struct MCDCDecisionCtx {
@@ -100,22 +100,22 @@ impl MCDCState {
             }
             None => decision_ctx.processing_decision.insert(MCDCDecisionSpan {
                 span,
-                conditions_num: 0,
+                num_conditions: 0,
                 end_markers: vec![],
                 decision_depth,
             }),
         };
 
         let parent_condition = decision_ctx.decision_stack.pop_back().unwrap_or_default();
         let lhs_id = if parent_condition.condition_id == ConditionId::NONE {
-            decision.conditions_num += 1;
-            ConditionId::from(decision.conditions_num)
+            decision.num_conditions += 1;
+            ConditionId::from(decision.num_conditions)
         } else {
             parent_condition.condition_id
         };
 
-        decision.conditions_num += 1;
-        let rhs_condition_id = ConditionId::from(decision.conditions_num);
+        decision.num_conditions += 1;
+        let rhs_condition_id = ConditionId::from(decision.num_conditions);
 
         let (lhs, rhs) = match op {
             LogicalOp::And => {
@@ -208,28 +208,28 @@ impl MCDCInfoBuilder {
         // is empty, i.e. when all the conditions of the decision were instrumented,
         // and the decision is "complete".
         if let Some(decision) = decision_result {
-            match decision.conditions_num {
+            match decision.num_conditions {
                 0 => {
                     unreachable!("Decision with no condition is not expected");
                 }
-                1..=MAX_CONDITIONS_NUM_IN_DECISION => {
+                1..=MAX_CONDITIONS_IN_DECISION => {
                     self.decision_spans.push(decision);
                 }
                 _ => {
                     // Do not generate mcdc mappings and statements for decisions with too many conditions.
                     // Therefore, first erase the condition info of the (N-1) previous branch spans.
-                    let rebase_idx = self.branch_spans.len() - (decision.conditions_num - 1);
+                    let rebase_idx = self.branch_spans.len() - (decision.num_conditions - 1);
                     for branch in &mut self.branch_spans[rebase_idx..] {
                         branch.condition_info = None;
                     }
 
                     // Then, erase this last branch span's info too, for a total of N.
                     condition_info = None;
 
-                    tcx.dcx().emit_warn(MCDCExceedsConditionNumLimit {
+                    tcx.dcx().emit_warn(MCDCExceedsConditionLimit {
                         span: decision.span,
-                        conditions_num: decision.conditions_num,
-                        max_conditions_num: MAX_CONDITIONS_NUM_IN_DECISION,
+                        num_conditions: decision.num_conditions,
+                        max_conditions: MAX_CONDITIONS_IN_DECISION,
                     });
                 }
             }

compiler/rustc_mir_build/src/errors.rs

@@ -812,12 +812,12 @@ pub struct NonEmptyNeverPattern<'tcx> {
 }
 
 #[derive(Diagnostic)]
-#[diag(mir_build_exceeds_mcdc_condition_num_limit)]
-pub(crate) struct MCDCExceedsConditionNumLimit {
+#[diag(mir_build_exceeds_mcdc_condition_limit)]
+pub(crate) struct MCDCExceedsConditionLimit {
     #[primary_span]
     pub span: Span,
-    pub conditions_num: usize,
-    pub max_conditions_num: usize,
+    pub num_conditions: usize,
+    pub max_conditions: usize,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_mir_transform/src/coverage/mappings.rs

@@ -48,7 +48,7 @@ pub(super) struct MCDCDecision {
     pub(super) span: Span,
     pub(super) end_bcbs: BTreeSet<BasicCoverageBlock>,
     pub(super) bitmap_idx: u32,
-    pub(super) conditions_num: u16,
+    pub(super) num_conditions: u16,
     pub(super) decision_depth: u16,
 }
 
@@ -268,13 +268,13 @@ pub(super) fn extract_mcdc_mappings(
             // the bitmap, rounded up to a whole number of bytes.
             // The decision's "bitmap index" points to its first byte in the bitmap.
             let bitmap_idx = *mcdc_bitmap_bytes;
-            *mcdc_bitmap_bytes += (1_u32 << decision.conditions_num).div_ceil(8);
+            *mcdc_bitmap_bytes += (1_u32 << decision.num_conditions).div_ceil(8);
 
             Some(MCDCDecision {
                 span,
                 end_bcbs,
                 bitmap_idx,
-                conditions_num: decision.conditions_num as u16,
+                num_conditions: decision.num_conditions as u16,
                 decision_depth: decision.decision_depth,
             })
         },

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -195,9 +195,9 @@ fn create_mappings<'tcx>(
     ));
 
     mappings.extend(mcdc_decisions.iter().filter_map(
-        |&mappings::MCDCDecision { span, bitmap_idx, conditions_num, .. }| {
+        |&mappings::MCDCDecision { span, bitmap_idx, num_conditions, .. }| {
             let code_region = region_for_span(span)?;
-            let kind = MappingKind::MCDCDecision(DecisionInfo { bitmap_idx, conditions_num });
+            let kind = MappingKind::MCDCDecision(DecisionInfo { bitmap_idx, num_conditions });
             Some(Mapping { kind, code_region })
         },
     ));
@@ -269,7 +269,7 @@ fn inject_mcdc_statements<'tcx>(
         span: _,
         ref end_bcbs,
         bitmap_idx,
-        conditions_num: _,
+        num_conditions: _,
         decision_depth,
     } in &extracted_mappings.mcdc_decisions
     {

library/core/src/ptr/mod.rs

@@ -450,8 +450,13 @@ mod mut_ptr;
 
 /// Executes the destructor (if any) of the pointed-to value.
 ///
-/// This is semantically equivalent to calling [`ptr::read`] and discarding
+/// This is almost the same as calling [`ptr::read`] and discarding
 /// the result, but has the following advantages:
+// FIXME: say something more useful than "almost the same"?
+// There are open questions here: `read` requires the value to be fully valid, e.g. if `T` is a
+// `bool` it must be 0 or 1, if it is a reference then it must be dereferenceable. `drop_in_place`
+// only requires that `*to_drop` be "valid for dropping" and we have not defined what that means. In
+// Miri it currently (May 2024) requires nothing at all for types without drop glue.
 ///
 /// * It is *required* to use `drop_in_place` to drop unsized types like
 ///   trait objects, because they can't be read out onto the stack and

library/core/src/time.rs

@@ -348,7 +348,7 @@ impl Duration {
     #[inline]
     pub const fn from_weeks(weeks: u64) -> Duration {
         if weeks > u64::MAX / (SECS_PER_MINUTE * MINS_PER_HOUR * HOURS_PER_DAY * DAYS_PER_WEEK) {
-            panic!("overflow in Duration::from_days");
+            panic!("overflow in Duration::from_weeks");
         }
 
         Duration::from_secs(weeks * MINS_PER_HOUR * SECS_PER_MINUTE * HOURS_PER_DAY * DAYS_PER_WEEK)

library/std/src/fs.rs

@@ -767,11 +767,33 @@ fn buffer_capacity_required(mut file: &File) -> Option<usize> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Read for &File {
+    /// Read some bytes from the file.
+    ///
+    /// See [`Read::read`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently corresponds to the `read` function on Unix and
+    /// the `NtReadFile` function on Windows. Note that this [may change in
+    /// the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
 
+    /// Like `read`, except that it reads into a slice of buffers.
+    ///
+    /// See [`Read::read_vectored`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently corresponds to the `readv` function on Unix and
+    /// falls back to the `read` implementation on Windows. Note that this
+    /// [may change in the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     #[inline]
     fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
         self.inner.read_vectored(bufs)
@@ -782,6 +804,16 @@ impl Read for &File {
         self.inner.read_buf(cursor)
     }
 
+    /// Determines if `File` has an efficient `read_vectored` implementation.
+    ///
+    /// See [`Read::is_read_vectored`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently returns `true` on Unix an `false` on Windows.
+    /// Note that this [may change in the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     #[inline]
     fn is_read_vectored(&self) -> bool {
         self.inner.is_read_vectored()
@@ -803,19 +835,63 @@ impl Read for &File {
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for &File {
+    /// Write some bytes from the file.
+    ///
+    /// See [`Write::write`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently corresponds to the `write` function on Unix and
+    /// the `NtWriteFile` function on Windows. Note that this [may change in
+    /// the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }
 
+    /// Like `write`, except that it writes into a slice of buffers.
+    ///
+    /// See [`Write::write_vectored`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently corresponds to the `writev` function on Unix
+    /// and falls back to the `write` implementation on Windows. Note that this
+    /// [may change in the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
         self.inner.write_vectored(bufs)
     }
 
+    /// Determines if `File` has an efficient `write_vectored` implementation.
+    ///
+    /// See [`Write::is_write_vectored`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// This function currently returns `true` on Unix an `false` on Windows.
+    /// Note that this [may change in the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     #[inline]
     fn is_write_vectored(&self) -> bool {
         self.inner.is_write_vectored()
     }
 
+    /// Flushes the file, ensuring that all intermediately buffered contents
+    /// reach their destination.
+    ///
+    /// See [`Write::flush`] docs for more info.
+    ///
+    /// # Platform-specific behavior
+    ///
+    /// Since a `File` structure doesn't contain any buffers, this function is
+    /// currently a no-op on Unix and Windows. Note that this [may change in
+    /// the future][changes].
+    ///
+    /// [changes]: io#platform-specific-behavior
     #[inline]
     fn flush(&mut self) -> io::Result<()> {
         self.inner.flush()