Struct rustc_mir_build::build::scope::Scope

struct Scope {
    source_scope: SourceScope,
    region_scope: Scope,
    region_scope_span: Span,
    drops: Vec<DropData>,
    moved_locals: Vec<Local>,
    cached_exits: FxHashMap<(BasicBlock, Scope), BasicBlock>,
    cached_generator_drop: Option<BasicBlock>,
    cached_unwind: CachedBlock,
}

Fields

source_scope: SourceScope

The source scope this scope was created in.

region_scope: Scope

the region span of this scope within source code.

region_scope_span: Span

the span of that region_scope

drops: Vec<DropData>

set of places to drop when exiting this scope. This starts out empty but grows as variables are declared during the building process. This is a stack, so we always drop from the end of the vector (top of the stack) first.

moved_locals: Vec<Local>

cached_exits: FxHashMap<(BasicBlock, Scope), BasicBlock>

The cache for drop chain on “normal” exit into a particular BasicBlock.

cached_generator_drop: Option<BasicBlock>

The cache for drop chain on "generator drop" exit.

cached_unwind: CachedBlock

The cache for drop chain on "unwind" exit.

Implementations

impl Scope

fn invalidate_cache(
    &mut self,
    storage_only: bool,
    generator_kind: Option<GeneratorKind>,
    this_scope_only: bool
)

Invalidates all the cached blocks in the scope.

Should always be run for all inner scopes when a drop is pushed into some scope enclosing a larger extent of code.

storage_only controls whether to invalidate only drop paths that run StorageDead. this_scope_only controls whether to invalidate only drop paths that refer to the current top-of-scope (as opposed to dependent scopes).

fn source_info(&self, span: Span) -> SourceInfo

Given a span and this scope's source scope, make a SourceInfo.

fn needs_cleanup(&self) -> bool

Whether there's anything to do for the cleanup path, that is, when unwinding through this scope. This includes destructors, but not StorageDead statements, which don't get emitted at all for unwinding, for several reasons:

• clang doesn't emit llvm.lifetime.end for C++ unwinding
• LLVM's memory dependency analysis can't handle it atm
• polluting the cleanup MIR with StorageDead creates landing pads even though there's no actual destructors
• freeing up stack space has no effect during unwinding Note that for generators we do emit StorageDeads, for the use of optimizations in the MIR generator transform.

Trait Implementations

impl Debug for Scope

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.