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Factor current-span logic into a lazy caching handle

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This commit is contained in:
Ben Kimock 2021-12-07 22:05:13 -05:00
parent 62ea0c8c39
commit b20c6cfd81
5 changed files with 79 additions and 62 deletions
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44
src/helpers.rs
View File

@ -2,7 +2,6 @@
use std::mem;
use std::num::NonZeroUsize;
use std::rc::Rc;
use std::time::Duration;
use log::trace;
@ -14,7 +13,7 @@
layout::{LayoutOf, TyAndLayout},
List, TyCtxt,
};
use rustc_span::{def_id::CrateNum, sym, Symbol};
use rustc_span::{def_id::CrateNum, sym, Span, Symbol};
use rustc_target::abi::{Align, FieldsShape, Size, Variants};
use rustc_target::spec::abi::Abi;
@ -800,6 +799,43 @@ fn item_link_name(&self, def_id: DefId) -> Symbol {
}
}
impl<'mir, 'tcx> Evaluator<'mir, 'tcx> {
pub fn current_span(&self) -> CurrentSpan<'_, 'mir, 'tcx> {
CurrentSpan { span: None, machine: self }
}
}
/// A `CurrentSpan` should be created infrequently (ideally once) per interpreter step. It does
/// nothing on creation, but when `CurrentSpan::get` is called, searches the current stack for the
/// topmost frame which corresponds to a local crate, and returns the current span in that frame.
/// The result of that search is cached so that later calls are approximately free.
#[derive(Clone)]
pub struct CurrentSpan<'a, 'tcx, 'mir> {
span: Option<Span>,
machine: &'a Evaluator<'tcx, 'mir>,
}
impl<'a, 'tcx, 'mir> CurrentSpan<'a, 'tcx, 'mir> {
pub fn get(&mut self) -> Span {
*self.span.get_or_insert_with(|| Self::current_span(&self.machine))
}
#[inline(never)]
fn current_span(machine: &Evaluator<'_, '_>) -> Span {
machine
.threads
.active_thread_stack()
.into_iter()
.rev()
.find(|frame| {
let def_id = frame.instance.def_id();
def_id.is_local() || machine.local_crates.contains(&def_id.krate)
})
.map(|frame| frame.current_span())
.unwrap_or(rustc_span::DUMMY_SP)
}
}
/// Check that the number of args is what we expect.
pub fn check_arg_count<'a, 'tcx, const N: usize>(
args: &'a [OpTy<'tcx, Tag>],
@ -822,7 +858,7 @@ pub fn isolation_abort_error(name: &str) -> InterpResult<'static> {
/// Retrieve the list of local crates that should have been passed by cargo-miri in
/// MIRI_LOCAL_CRATES and turn them into `CrateNum`s.
pub fn get_local_crates(tcx: &TyCtxt<'_>) -> Rc<[CrateNum]> {
pub fn get_local_crates(tcx: &TyCtxt<'_>) -> Vec<CrateNum> {
// Convert the local crate names from the passed-in config into CrateNums so that they can
// be looked up quickly during execution
let local_crate_names = std::env::var("MIRI_LOCAL_CRATES")
@ -836,7 +872,7 @@ pub fn get_local_crates(tcx: &TyCtxt<'_>) -> Rc<[CrateNum]> {
local_crates.push(crate_num);
}
}
Rc::from(local_crates.as_slice())
local_crates
}
/// Formats an AllocRange like [0x1..0x3], for use in diagnostics.

2
src/lib.rs
View File

@ -77,7 +77,7 @@
pub use crate::eval::{
create_ecx, eval_entry, AlignmentCheck, BacktraceStyle, IsolatedOp, MiriConfig, RejectOpWith,
};
pub use crate::helpers::EvalContextExt as HelpersEvalContextExt;
pub use crate::helpers::{CurrentSpan, EvalContextExt as HelpersEvalContextExt};
pub use crate::machine::{
AllocExtra, Evaluator, FrameData, MiriEvalContext, MiriEvalContextExt, MiriMemoryKind, Tag,
NUM_CPUS, PAGE_SIZE, STACK_ADDR, STACK_SIZE,

10
src/machine.rs
View File

@ -6,7 +6,6 @@
use std::collections::HashSet;
use std::fmt;
use std::num::NonZeroU64;
use std::rc::Rc;
use std::time::Instant;
use rand::rngs::StdRng;
@ -278,7 +277,7 @@ pub struct Evaluator<'mir, 'tcx> {
pub(crate) backtrace_style: BacktraceStyle,
/// Crates which are considered local for the purposes of error reporting.
pub(crate) local_crates: Rc<[CrateNum]>,
pub(crate) local_crates: Vec<CrateNum>,
/// Mapping extern static names to their base pointer.
extern_statics: FxHashMap<Symbol, Pointer<Tag>>,
@ -584,8 +583,7 @@ fn init_allocation_extra<'b>(
alloc.size(),
stacked_borrows,
kind,
&ecx.machine.threads,
ecx.machine.local_crates.clone(),
ecx.machine.current_span(),
))
} else {
None
@ -667,7 +665,7 @@ fn memory_read(
tag,
range,
machine.stacked_borrows.as_ref().unwrap(),
&machine.threads,
machine.current_span(),
)
} else {
Ok(())
@ -691,7 +689,7 @@ fn memory_written(
tag,
range,
machine.stacked_borrows.as_ref().unwrap(),
&machine.threads,
machine.current_span(),
)
} else {
Ok(())

45
src/stacked_borrows.rs
View File

@ -5,7 +5,6 @@
use std::cell::RefCell;
use std::fmt;
use std::num::NonZeroU64;
use std::rc::Rc;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_hir::Mutability;
@ -14,7 +13,6 @@
self,
layout::{HasParamEnv, LayoutOf},
};
use rustc_span::def_id::CrateNum;
use rustc_span::DUMMY_SP;
use rustc_target::abi::Size;
use std::collections::HashSet;
@ -22,9 +20,7 @@
use crate::*;
pub mod diagnostics;
use diagnostics::AllocHistory;
use diagnostics::TagHistory;
use diagnostics::{AllocHistory, TagHistory};
pub type PtrId = NonZeroU64;
pub type CallId = NonZeroU64;
@ -376,7 +372,7 @@ fn access(
tag: SbTag,
(alloc_id, alloc_range, offset): (AllocId, AllocRange, Size), // just for debug printing and error messages
global: &mut GlobalStateInner,
threads: &ThreadManager<'_, 'tcx>,
current_span: &mut CurrentSpan<'_, '_, 'tcx>,
alloc_history: &mut AllocHistory,
) -> InterpResult<'tcx> {
// Two main steps: Find granting item, remove incompatible items above.
@ -400,7 +396,7 @@ fn access(
global,
alloc_history,
)?;
alloc_history.log_invalidation(item.tag, alloc_range, threads);
alloc_history.log_invalidation(item.tag, alloc_range, current_span);
}
} else {
// On a read, *disable* all `Unique` above the granting item. This ensures U2 for read accesses.
@ -422,7 +418,7 @@ fn access(
alloc_history,
)?;
item.perm = Permission::Disabled;
alloc_history.log_invalidation(item.tag, alloc_range, threads);
alloc_history.log_invalidation(item.tag, alloc_range, current_span);
}
}
}
@ -471,7 +467,7 @@ fn grant(
new: Item,
(alloc_id, alloc_range, offset): (AllocId, AllocRange, Size), // just for debug printing and error messages
global: &mut GlobalStateInner,
threads: &ThreadManager<'_, 'tcx>,
current_span: &mut CurrentSpan<'_, '_, 'tcx>,
alloc_history: &mut AllocHistory,
) -> InterpResult<'tcx> {
// Figure out which access `perm` corresponds to.
@ -505,7 +501,7 @@ fn grant(
derived_from,
(alloc_id, alloc_range, offset),
global,
threads,
current_span,
alloc_history,
)?;
@ -533,13 +529,13 @@ fn grant(
/// Map per-stack operations to higher-level per-location-range operations.
impl<'tcx> Stacks {
/// Creates new stack with initial tag.
fn new(size: Size, perm: Permission, tag: SbTag, local_crates: Rc<[CrateNum]>) -> Self {
fn new(size: Size, perm: Permission, tag: SbTag) -> Self {
let item = Item { perm, tag, protector: None };
let stack = Stack { borrows: vec![item] };
Stacks {
stacks: RefCell::new(RangeMap::new(size, stack)),
history: RefCell::new(AllocHistory::new(local_crates)),
history: RefCell::new(AllocHistory::new()),
}
}
@ -579,8 +575,7 @@ pub fn new_allocation(
size: Size,
state: &GlobalState,
kind: MemoryKind<MiriMemoryKind>,
threads: &ThreadManager<'_, '_>,
local_crates: Rc<[CrateNum]>,
mut current_span: CurrentSpan<'_, '_, '_>,
) -> Self {
let mut extra = state.borrow_mut();
let (base_tag, perm) = match kind {
@ -614,12 +609,12 @@ pub fn new_allocation(
(tag, Permission::SharedReadWrite)
}
};
let stacks = Stacks::new(size, perm, base_tag, local_crates);
let stacks = Stacks::new(size, perm, base_tag);
stacks.history.borrow_mut().log_creation(
None,
base_tag,
alloc_range(Size::ZERO, size),
threads,
&mut current_span,
);
stacks
}
@ -631,7 +626,7 @@ pub fn memory_read<'tcx>(
tag: SbTag,
range: AllocRange,
state: &GlobalState,
threads: &ThreadManager<'_, 'tcx>,
mut current_span: CurrentSpan<'_, '_, 'tcx>,
) -> InterpResult<'tcx> {
trace!(
"read access with tag {:?}: {:?}, size {}",
@ -646,7 +641,7 @@ pub fn memory_read<'tcx>(
tag,
(alloc_id, range, offset),
&mut state,
threads,
&mut current_span,
history,
)
})
@ -659,7 +654,7 @@ pub fn memory_written<'tcx>(
tag: SbTag,
range: AllocRange,
state: &GlobalState,
threads: &ThreadManager<'_, 'tcx>,
mut current_span: CurrentSpan<'_, '_, 'tcx>,
) -> InterpResult<'tcx> {
trace!(
"write access with tag {:?}: {:?}, size {}",
@ -674,7 +669,7 @@ pub fn memory_written<'tcx>(
tag,
(alloc_id, range, offset),
&mut state,
threads,
&mut current_span,
history,
)
})
@ -723,6 +718,7 @@ fn reborrow(
}
let (alloc_id, base_offset, orig_tag) = this.ptr_get_alloc_id(place.ptr)?;
let mut current_span = this.machine.current_span();
{
let extra = this.get_alloc_extra(alloc_id)?;
let stacked_borrows =
@ -732,10 +728,10 @@ fn reborrow(
Some(orig_tag),
new_tag,
alloc_range(base_offset, size),
&this.machine.threads,
&mut current_span,
);
if protect {
alloc_history.log_protector(orig_tag, new_tag, &this.machine.threads);
alloc_history.log_protector(orig_tag, new_tag, &mut current_span);
}
}
@ -804,7 +800,7 @@ fn reborrow(
item,
(alloc_id, range, offset),
&mut *global,
&this.machine.threads,
&mut current_span,
history,
)
})
@ -821,13 +817,14 @@ fn reborrow(
let item = Item { perm, tag: new_tag, protector };
let range = alloc_range(base_offset, size);
let mut global = machine.stacked_borrows.as_ref().unwrap().borrow_mut();
let mut current_span = machine.current_span();
stacked_borrows.for_each_mut(range, |offset, stack, history| {
stack.grant(
orig_tag,
item,
(alloc_id, range, offset),
&mut global,
&machine.threads,
&mut current_span,
history,
)
})?;

40
src/stacked_borrows/diagnostics.rs
View File

@ -1,17 +1,14 @@
use smallvec::SmallVec;
use std::rc::Rc;
use rustc_middle::mir::interpret::{AllocId, AllocRange};
use rustc_span::def_id::CrateNum;
use rustc_span::{Span, SpanData};
use rustc_target::abi::Size;
use crate::helpers::HexRange;
use crate::helpers::{CurrentSpan, HexRange};
use crate::stacked_borrows::{err_sb_ub, AccessKind, Permission};
use crate::Item;
use crate::SbTag;
use crate::Stack;
use crate::ThreadManager;
use rustc_middle::mir::interpret::InterpError;
@ -23,8 +20,6 @@ pub struct AllocHistory {
creations: smallvec::SmallVec<[Event; 2]>,
invalidations: smallvec::SmallVec<[Event; 1]>,
protectors: smallvec::SmallVec<[Protection; 1]>,
/// This field is a clone of the `local_crates` field on `Evaluator`.
local_crates: Rc<[CrateNum]>,
}
#[derive(Clone, Debug)]
@ -59,37 +54,23 @@ pub enum TagHistory {
}
impl AllocHistory {
pub fn new(local_crates: Rc<[CrateNum]>) -> Self {
pub fn new() -> Self {
Self {
current_time: 0,
creations: SmallVec::new(),
invalidations: SmallVec::new(),
protectors: SmallVec::new(),
local_crates,
}
}
fn current_span(&self, threads: &ThreadManager<'_, '_>) -> Span {
threads
.active_thread_stack()
.into_iter()
.rev()
.find(|frame| {
let def_id = frame.instance.def_id();
def_id.is_local() || self.local_crates.contains(&def_id.krate)
})
.map(|frame| frame.current_span())
.unwrap_or(rustc_span::DUMMY_SP)
}
pub fn log_creation(
&mut self,
parent: Option<SbTag>,
tag: SbTag,
range: AllocRange,
threads: &ThreadManager<'_, '_>,
current_span: &mut CurrentSpan<'_, '_, '_>,
) {
let span = self.current_span(threads);
let span = current_span.get();
self.creations.push(Event { parent, tag, range, span, time: self.current_time });
self.current_time += 1;
}
@ -98,15 +79,20 @@ pub fn log_invalidation(
&mut self,
tag: SbTag,
range: AllocRange,
threads: &ThreadManager<'_, '_>,
current_span: &mut CurrentSpan<'_, '_, '_>,
) {
let span = self.current_span(threads);
let span = current_span.get();
self.invalidations.push(Event { parent: None, tag, range, span, time: self.current_time });
self.current_time += 1;
}
pub fn log_protector(&mut self, orig_tag: SbTag, tag: SbTag, threads: &ThreadManager<'_, '_>) {
let span = self.current_span(threads);
pub fn log_protector(
&mut self,
orig_tag: SbTag,
tag: SbTag,
current_span: &mut CurrentSpan<'_, '_, '_>,
) {
let span = current_span.get();
self.protectors.push(Protection { orig_tag, tag, span });
self.current_time += 1;
}