Miri: rename "undef" to "uninit"
renamed Allocation::check_defined_and_ptr to Allocation::check_init_and_ptr renamed Allocation::check_defined_and_ptr to Allocation::check_init_and_ptr in src/librustc_middle/mir/interpret/allocation.rs renamed Allocation::is_defined and Allocation::check_defined, fixed documentation renamed Allocation::is_defined and Allocation::check_defined to is_init and check_init respectively. Fixed documentation so it correctly refers to "initialization" instead of "defined"-ness renamed Allocation::mark_definedness renamed Allocation::mark_definedness to Allocation::mark_init Renamed new_state parameter in Allocation::mark_init Renamed new_state to is_init, as the latter is more descriptive. renamed functions in AllocationDefinedness renamed AllocationDefinedness::all_bytes_undef and AllocationDefinedness::mark_compressed_undef_range to no_bytes_init and mark_compressed_init_range respectively. renamed AllocationDefinedness to InitMaskCompressed renamed Immediate::to_scalar_or_undef renamed to to_scalar_or_uninit fixed comment references to "undef" Changed comments referring to "undef" and "definedness" to "initialization" and "initialization state" in src/librustc_mir/interpret/memory.rs and src/librustc_middle/mir/interpret/allocation.rs changed references to "undef" in comments and a variable Changed some comments referring to "undef" to use "uninitialized" instead. Also changed a variable from "undef_end" to "uninit_end". All changes were made within src/librustc_middle/mir/interpret/allocation.rs. Changed more comments referring to undef Changed comments to use "uninitialized" instead of "undef" in src/librustc_middle/mir/interpret/allocation.rs.
This commit is contained in:
Philippe Nadon
parent
55984b65ce
commit
ef9c4f5cef
@ -105,7 +105,7 @@ impl<Tag> Allocation<Tag> {
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Allocation::from_bytes(slice, Align::from_bytes(1).unwrap())
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}
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pub fn undef(size: Size, align: Align) -> Self {
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pub fn uninit(size: Size, align: Align) -> Self {
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Allocation {
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bytes: vec![0; size.bytes_usize()],
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relocations: Relocations::new(),
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@ -153,7 +153,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
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self.size.bytes_usize()
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}
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/// Looks at a slice which may describe undefined bytes or describe a relocation. This differs
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/// Looks at a slice which may describe uninitialized bytes or describe a relocation. This differs
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/// from `get_bytes_with_undef_and_ptr` in that it does no relocation checks (even on the
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/// edges) at all. It further ignores `AllocationExtra` callbacks.
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/// This must not be used for reads affecting the interpreter execution.
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@ -192,7 +192,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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offset.bytes_usize()..end
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}
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/// The last argument controls whether we error out when there are undefined
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/// The last argument controls whether we error out when there are uninitialized
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/// or pointer bytes. You should never call this, call `get_bytes` or
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/// `get_bytes_with_undef_and_ptr` instead,
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///
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@ -206,12 +206,12 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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cx: &impl HasDataLayout,
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ptr: Pointer<Tag>,
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size: Size,
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check_defined_and_ptr: bool,
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check_init_and_ptr: bool,
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) -> InterpResult<'tcx, &[u8]> {
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let range = self.check_bounds(ptr.offset, size);
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if check_defined_and_ptr {
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self.check_defined(ptr, size)?;
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if check_init_and_ptr {
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self.check_init(ptr, size)?;
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self.check_relocations(cx, ptr, size)?;
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} else {
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// We still don't want relocations on the *edges*.
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@ -239,7 +239,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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self.get_bytes_internal(cx, ptr, size, true)
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}
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/// It is the caller's responsibility to handle undefined and pointer bytes.
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/// It is the caller's responsibility to handle uninitialized and pointer bytes.
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/// However, this still checks that there are no relocations on the *edges*.
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///
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/// It is the caller's responsibility to check bounds and alignment beforehand.
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@ -267,7 +267,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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) -> InterpResult<'tcx, &mut [u8]> {
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let range = self.check_bounds(ptr.offset, size);
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self.mark_definedness(ptr, size, true);
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self.mark_init(ptr, size, true);
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self.clear_relocations(cx, ptr, size)?;
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AllocationExtra::memory_written(self, ptr, size)?;
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@ -303,7 +303,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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/// Validates that `ptr.offset` and `ptr.offset + size` do not point to the middle of a
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/// relocation. If `allow_ptr_and_undef` is `false`, also enforces that the memory in the
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/// given range contains neither relocations nor undef bytes.
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/// given range contains neither relocations nor uninitialized bytes.
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pub fn check_bytes(
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&self,
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cx: &impl HasDataLayout,
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@ -313,9 +313,9 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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) -> InterpResult<'tcx> {
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// Check bounds and relocations on the edges.
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self.get_bytes_with_undef_and_ptr(cx, ptr, size)?;
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// Check undef and ptr.
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// Check uninit and ptr.
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if !allow_ptr_and_undef {
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self.check_defined(ptr, size)?;
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self.check_init(ptr, size)?;
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self.check_relocations(cx, ptr, size)?;
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}
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Ok(())
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@ -364,7 +364,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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let bytes = self.get_bytes_with_undef_and_ptr(cx, ptr, size)?;
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// Uninit check happens *after* we established that the alignment is correct.
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// We must not return `Ok()` for unaligned pointers!
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if self.is_defined(ptr, size).is_err() {
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if self.is_init(ptr, size).is_err() {
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// This inflates uninitialized bytes to the entire scalar, even if only a few
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// bytes are uninitialized.
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return Ok(ScalarMaybeUninit::Uninit);
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@ -416,7 +416,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
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let val = match val {
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ScalarMaybeUninit::Scalar(scalar) => scalar,
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ScalarMaybeUninit::Uninit => {
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self.mark_definedness(ptr, type_size, false);
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self.mark_init(ptr, type_size, false);
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return Ok(());
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}
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};
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@ -512,7 +512,7 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
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let start = ptr.offset;
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let end = start + size; // `Size` addition
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// Mark parts of the outermost relocations as undefined if they partially fall outside the
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// Mark parts of the outermost relocations as uninitialized if they partially fall outside the
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// given range.
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if first < start {
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self.init_mask.set_range(first, start, false);
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@ -542,20 +542,20 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
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}
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}
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/// Undefined bytes.
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/// Uninitialized bytes.
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impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
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/// Checks whether the given range is entirely defined.
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/// Checks whether the given range is entirely initialized.
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///
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/// Returns `Ok(())` if it's defined. Otherwise returns the range of byte
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/// indexes of the first contiguous undefined access.
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fn is_defined(&self, ptr: Pointer<Tag>, size: Size) -> Result<(), Range<Size>> {
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/// Returns `Ok(())` if it's initialized. Otherwise returns the range of byte
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/// indexes of the first contiguous uninitialized access.
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fn is_init(&self, ptr: Pointer<Tag>, size: Size) -> Result<(), Range<Size>> {
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self.init_mask.is_range_initialized(ptr.offset, ptr.offset + size) // `Size` addition
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}
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/// Checks that a range of bytes is defined. If not, returns the `InvalidUndefBytes`
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/// error which will report the first range of bytes which is undefined.
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fn check_defined(&self, ptr: Pointer<Tag>, size: Size) -> InterpResult<'tcx> {
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self.is_defined(ptr, size).or_else(|idx_range| {
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/// Checks that a range of bytes is initialized. If not, returns the `InvalidUninitBytes`
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/// error which will report the first range of bytes which is uninitialized.
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fn check_init(&self, ptr: Pointer<Tag>, size: Size) -> InterpResult<'tcx> {
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self.is_init(ptr, size).or_else(|idx_range| {
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throw_ub!(InvalidUninitBytes(Some(Box::new(UninitBytesAccess {
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access_ptr: ptr.erase_tag(),
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access_size: size,
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@ -565,44 +565,44 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
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})
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}
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pub fn mark_definedness(&mut self, ptr: Pointer<Tag>, size: Size, new_state: bool) {
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pub fn mark_init(&mut self, ptr: Pointer<Tag>, size: Size, is_init: bool) {
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if size.bytes() == 0 {
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return;
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}
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self.init_mask.set_range(ptr.offset, ptr.offset + size, new_state);
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self.init_mask.set_range(ptr.offset, ptr.offset + size, is_init);
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}
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}
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/// Run-length encoding of the undef mask.
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/// Run-length encoding of the uninit mask.
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/// Used to copy parts of a mask multiple times to another allocation.
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pub struct AllocationDefinedness {
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/// The definedness of the first range.
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pub struct InitMaskCompressed {
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/// Whether the first range is initialized.
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initial: bool,
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/// The lengths of ranges that are run-length encoded.
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/// The definedness of the ranges alternate starting with `initial`.
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/// The initialization state of the ranges alternate starting with `initial`.
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ranges: smallvec::SmallVec<[u64; 1]>,
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}
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impl AllocationDefinedness {
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pub fn all_bytes_undef(&self) -> bool {
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// The `ranges` are run-length encoded and of alternating definedness.
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// So if `ranges.len() > 1` then the second block is a range of defined.
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impl InitMaskCompressed {
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pub fn no_bytes_init(&self) -> bool {
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// The `ranges` are run-length encoded and of alternating initialization state.
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// So if `ranges.len() > 1` then the second block is an initialized range.
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!self.initial && self.ranges.len() == 1
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}
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}
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/// Transferring the definedness mask to other allocations.
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/// Transferring the initialization mask to other allocations.
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impl<Tag, Extra> Allocation<Tag, Extra> {
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/// Creates a run-length encoding of the undef mask.
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pub fn compress_undef_range(&self, src: Pointer<Tag>, size: Size) -> AllocationDefinedness {
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/// Creates a run-length encoding of the initialization mask.
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pub fn compress_undef_range(&self, src: Pointer<Tag>, size: Size) -> InitMaskCompressed {
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// Since we are copying `size` bytes from `src` to `dest + i * size` (`for i in 0..repeat`),
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// a naive undef mask copying algorithm would repeatedly have to read the undef mask from
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// a naive initialization mask copying algorithm would repeatedly have to read the initialization mask from
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// the source and write it to the destination. Even if we optimized the memory accesses,
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// we'd be doing all of this `repeat` times.
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// Therefore we precompute a compressed version of the undef mask of the source value and
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// Therefore we precompute a compressed version of the initialization mask of the source value and
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// then write it back `repeat` times without computing any more information from the source.
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// A precomputed cache for ranges of defined/undefined bits
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// A precomputed cache for ranges of initialized / uninitialized bits
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// 0000010010001110 will become
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// `[5, 1, 2, 1, 3, 3, 1]`,
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// where each element toggles the state.
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@ -613,7 +613,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
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let mut cur = initial;
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for i in 1..size.bytes() {
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// FIXME: optimize to bitshift the current undef block's bits and read the top bit.
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// FIXME: optimize to bitshift the current uninitialized block's bits and read the top bit.
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if self.init_mask.get(src.offset + Size::from_bytes(i)) == cur {
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cur_len += 1;
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} else {
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@ -625,13 +625,13 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
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ranges.push(cur_len);
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AllocationDefinedness { ranges, initial }
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InitMaskCompressed { ranges, initial }
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}
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/// Applies multiple instances of the run-length encoding to the undef mask.
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pub fn mark_compressed_undef_range(
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/// Applies multiple instances of the run-length encoding to the initialization mask.
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pub fn mark_compressed_init_range(
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&mut self,
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defined: &AllocationDefinedness,
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defined: &InitMaskCompressed,
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dest: Pointer<Tag>,
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size: Size,
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repeat: u64,
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@ -740,7 +740,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
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}
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////////////////////////////////////////////////////////////////////////////////
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// Undefined byte tracking
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// Uninitialized byte tracking
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////////////////////////////////////////////////////////////////////////////////
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type Block = u64;
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@ -778,11 +778,11 @@ impl InitMask {
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match idx {
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Some(idx) => {
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let undef_end = (idx.bytes()..end.bytes())
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let uninit_end = (idx.bytes()..end.bytes())
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.map(Size::from_bytes)
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.find(|&i| self.get(i))
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.unwrap_or(end);
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Err(idx..undef_end)
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Err(idx..uninit_end)
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}
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None => Ok(()),
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}
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@ -171,7 +171,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
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align: Align,
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kind: MemoryKind<M::MemoryKind>,
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) -> Pointer<M::PointerTag> {
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let alloc = Allocation::undef(size, align);
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let alloc = Allocation::uninit(size, align);
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self.allocate_with(alloc, kind)
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}
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@ -904,18 +904,18 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
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let dest_bytes = dest_bytes.as_mut_ptr();
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// Prepare a copy of the undef mask.
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// Prepare a copy of the initialization mask.
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let compressed = self.get_raw(src.alloc_id)?.compress_undef_range(src, size);
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if compressed.all_bytes_undef() {
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// Fast path: If all bytes are `undef` then there is nothing to copy. The target range
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// is marked as undef but we otherwise omit changing the byte representation which may
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// be arbitrary for undef bytes.
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if compressed.no_bytes_init() {
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// Fast path: If all bytes are `uninit` then there is nothing to copy. The target range
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// is marked as unititialized but we otherwise omit changing the byte representation which may
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// be arbitrary for uninitialized bytes.
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// This also avoids writing to the target bytes so that the backing allocation is never
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// touched if the bytes stay undef for the whole interpreter execution. On contemporary
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// touched if the bytes stay uninitialized for the whole interpreter execution. On contemporary
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// operating system this can avoid physically allocating the page.
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let dest_alloc = self.get_raw_mut(dest.alloc_id)?;
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dest_alloc.mark_definedness(dest, size * length, false); // `Size` multiplication
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dest_alloc.mark_init(dest, size * length, false); // `Size` multiplication
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dest_alloc.mark_relocation_range(relocations);
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return Ok(());
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}
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@ -955,7 +955,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
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}
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// now fill in all the data
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self.get_raw_mut(dest.alloc_id)?.mark_compressed_undef_range(
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self.get_raw_mut(dest.alloc_id)?.mark_compressed_init_range(
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&compressed,
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dest,
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size,
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@ -63,7 +63,7 @@ impl<'tcx, Tag> Immediate<Tag> {
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}
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#[inline]
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pub fn to_scalar_or_undef(self) -> ScalarMaybeUninit<Tag> {
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pub fn to_scalar_or_uninit(self) -> ScalarMaybeUninit<Tag> {
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match self {
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Immediate::Scalar(val) => val,
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Immediate::ScalarPair(..) => bug!("Got a wide pointer where a scalar was expected"),
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@ -72,7 +72,7 @@ impl<'tcx, Tag> Immediate<Tag> {
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#[inline]
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pub fn to_scalar(self) -> InterpResult<'tcx, Scalar<Tag>> {
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self.to_scalar_or_undef().check_init()
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self.to_scalar_or_uninit().check_init()
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}
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#[inline]
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@ -333,7 +333,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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&self,
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op: OpTy<'tcx, M::PointerTag>,
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) -> InterpResult<'tcx, ScalarMaybeUninit<M::PointerTag>> {
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Ok(self.read_immediate(op)?.to_scalar_or_undef())
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Ok(self.read_immediate(op)?.to_scalar_or_uninit())
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}
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// Turn the wide MPlace into a string (must already be dereferenced!)
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