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Diffstat (limited to 'compiler/rustc_mir_transform/src/coverage/tests.rs')
| -rw-r--r-- | compiler/rustc_mir_transform/src/coverage/tests.rs | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/compiler/rustc_mir_transform/src/coverage/tests.rs b/compiler/rustc_mir_transform/src/coverage/tests.rs new file mode 100644 index 000000000..6380f0352 --- /dev/null +++ b/compiler/rustc_mir_transform/src/coverage/tests.rs @@ -0,0 +1,710 @@ +//! This crate hosts a selection of "unit tests" for components of the `InstrumentCoverage` MIR +//! pass. +//! +//! ```shell +//! ./x.py test --keep-stage 1 compiler/rustc_mir --test-args '--show-output coverage' +//! ``` +//! +//! The tests construct a few "mock" objects, as needed, to support the `InstrumentCoverage` +//! functions and algorithms. Mocked objects include instances of `mir::Body`; including +//! `Terminator`s of various `kind`s, and `Span` objects. Some functions used by or used on +//! real, runtime versions of these mocked-up objects have constraints (such as cross-thread +//! limitations) and deep dependencies on other elements of the full Rust compiler (which is +//! *not* constructed or mocked for these tests). +//! +//! Of particular note, attempting to simply print elements of the `mir::Body` with default +//! `Debug` formatting can fail because some `Debug` format implementations require the +//! `TyCtxt`, obtained via a static global variable that is *not* set for these tests. +//! Initializing the global type context is prohibitively complex for the scope and scale of these +//! tests (essentially requiring initializing the entire compiler). +//! +//! Also note, some basic features of `Span` also rely on the `Span`s own "session globals", which +//! are unrelated to the `TyCtxt` global. Without initializing the `Span` session globals, some +//! basic, coverage-specific features would be impossible to test, but thankfully initializing these +//! globals is comparatively simpler. The easiest way is to wrap the test in a closure argument +//! to: `rustc_span::create_default_session_globals_then(|| { test_here(); })`. + +use super::counters; +use super::debug; +use super::graph; +use super::spans; + +use coverage_test_macros::let_bcb; + +use itertools::Itertools; +use rustc_data_structures::graph::WithNumNodes; +use rustc_data_structures::graph::WithSuccessors; +use rustc_index::vec::{Idx, IndexVec}; +use rustc_middle::mir::coverage::CoverageKind; +use rustc_middle::mir::*; +use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_span::{self, BytePos, Pos, Span, DUMMY_SP}; + +// All `TEMP_BLOCK` targets should be replaced before calling `to_body() -> mir::Body`. +const TEMP_BLOCK: BasicBlock = BasicBlock::MAX; + +struct MockBlocks<'tcx> { + blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, + dummy_place: Place<'tcx>, + next_local: usize, + bool_ty: Ty<'tcx>, +} + +impl<'tcx> MockBlocks<'tcx> { + fn new() -> Self { + Self { + blocks: IndexVec::new(), + dummy_place: Place { local: RETURN_PLACE, projection: ty::List::empty() }, + next_local: 0, + bool_ty: TyCtxt::BOOL_TY_FOR_UNIT_TESTING, + } + } + + fn new_temp(&mut self) -> Local { + let index = self.next_local; + self.next_local += 1; + Local::new(index) + } + + fn push(&mut self, kind: TerminatorKind<'tcx>) -> BasicBlock { + let next_lo = if let Some(last) = self.blocks.last() { + self.blocks[last].terminator().source_info.span.hi() + } else { + BytePos(1) + }; + let next_hi = next_lo + BytePos(1); + self.blocks.push(BasicBlockData { + statements: vec![], + terminator: Some(Terminator { + source_info: SourceInfo::outermost(Span::with_root_ctxt(next_lo, next_hi)), + kind, + }), + is_cleanup: false, + }) + } + + fn link(&mut self, from_block: BasicBlock, to_block: BasicBlock) { + match self.blocks[from_block].terminator_mut().kind { + TerminatorKind::Assert { ref mut target, .. } + | TerminatorKind::Call { target: Some(ref mut target), .. } + | TerminatorKind::Drop { ref mut target, .. } + | TerminatorKind::DropAndReplace { ref mut target, .. } + | TerminatorKind::FalseEdge { real_target: ref mut target, .. } + | TerminatorKind::FalseUnwind { real_target: ref mut target, .. } + | TerminatorKind::Goto { ref mut target } + | TerminatorKind::InlineAsm { destination: Some(ref mut target), .. } + | TerminatorKind::Yield { resume: ref mut target, .. } => *target = to_block, + ref invalid => bug!("Invalid from_block: {:?}", invalid), + } + } + + fn add_block_from( + &mut self, + some_from_block: Option<BasicBlock>, + to_kind: TerminatorKind<'tcx>, + ) -> BasicBlock { + let new_block = self.push(to_kind); + if let Some(from_block) = some_from_block { + self.link(from_block, new_block); + } + new_block + } + + fn set_branch(&mut self, switchint: BasicBlock, branch_index: usize, to_block: BasicBlock) { + match self.blocks[switchint].terminator_mut().kind { + TerminatorKind::SwitchInt { ref mut targets, .. } => { + let mut branches = targets.iter().collect::<Vec<_>>(); + let otherwise = if branch_index == branches.len() { + to_block + } else { + let old_otherwise = targets.otherwise(); + if branch_index > branches.len() { + branches.push((branches.len() as u128, old_otherwise)); + while branches.len() < branch_index { + branches.push((branches.len() as u128, TEMP_BLOCK)); + } + to_block + } else { + branches[branch_index] = (branch_index as u128, to_block); + old_otherwise + } + }; + *targets = SwitchTargets::new(branches.into_iter(), otherwise); + } + ref invalid => bug!("Invalid BasicBlock kind or no to_block: {:?}", invalid), + } + } + + fn call(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock { + self.add_block_from( + some_from_block, + TerminatorKind::Call { + func: Operand::Copy(self.dummy_place.clone()), + args: vec![], + destination: self.dummy_place.clone(), + target: Some(TEMP_BLOCK), + cleanup: None, + from_hir_call: false, + fn_span: DUMMY_SP, + }, + ) + } + + fn goto(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock { + self.add_block_from(some_from_block, TerminatorKind::Goto { target: TEMP_BLOCK }) + } + + fn switchint(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock { + let switchint_kind = TerminatorKind::SwitchInt { + discr: Operand::Move(Place::from(self.new_temp())), + switch_ty: self.bool_ty, // just a dummy value + targets: SwitchTargets::static_if(0, TEMP_BLOCK, TEMP_BLOCK), + }; + self.add_block_from(some_from_block, switchint_kind) + } + + fn return_(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock { + self.add_block_from(some_from_block, TerminatorKind::Return) + } + + fn to_body(self) -> Body<'tcx> { + Body::new_cfg_only(self.blocks) + } +} + +fn debug_basic_blocks<'tcx>(mir_body: &Body<'tcx>) -> String { + format!( + "{:?}", + mir_body + .basic_blocks() + .iter_enumerated() + .map(|(bb, data)| { + let term = &data.terminator(); + let kind = &term.kind; + let span = term.source_info.span; + let sp = format!("(span:{},{})", span.lo().to_u32(), span.hi().to_u32()); + match kind { + TerminatorKind::Assert { target, .. } + | TerminatorKind::Call { target: Some(target), .. } + | TerminatorKind::Drop { target, .. } + | TerminatorKind::DropAndReplace { target, .. } + | TerminatorKind::FalseEdge { real_target: target, .. } + | TerminatorKind::FalseUnwind { real_target: target, .. } + | TerminatorKind::Goto { target } + | TerminatorKind::InlineAsm { destination: Some(target), .. } + | TerminatorKind::Yield { resume: target, .. } => { + format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), target) + } + TerminatorKind::SwitchInt { targets, .. } => { + format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), targets) + } + _ => format!("{}{:?}:{}", sp, bb, debug::term_type(kind)), + } + }) + .collect::<Vec<_>>() + ) +} + +static PRINT_GRAPHS: bool = false; + +fn print_mir_graphviz(name: &str, mir_body: &Body<'_>) { + if PRINT_GRAPHS { + println!( + "digraph {} {{\n{}\n}}", + name, + mir_body + .basic_blocks() + .iter_enumerated() + .map(|(bb, data)| { + format!( + " {:?} [label=\"{:?}: {}\"];\n{}", + bb, + bb, + debug::term_type(&data.terminator().kind), + mir_body + .basic_blocks + .successors(bb) + .map(|successor| { format!(" {:?} -> {:?};", bb, successor) }) + .join("\n") + ) + }) + .join("\n") + ); + } +} + +fn print_coverage_graphviz( + name: &str, + mir_body: &Body<'_>, + basic_coverage_blocks: &graph::CoverageGraph, +) { + if PRINT_GRAPHS { + println!( + "digraph {} {{\n{}\n}}", + name, + basic_coverage_blocks + .iter_enumerated() + .map(|(bcb, bcb_data)| { + format!( + " {:?} [label=\"{:?}: {}\"];\n{}", + bcb, + bcb, + debug::term_type(&bcb_data.terminator(mir_body).kind), + basic_coverage_blocks + .successors(bcb) + .map(|successor| { format!(" {:?} -> {:?};", bcb, successor) }) + .join("\n") + ) + }) + .join("\n") + ); + } +} + +/// Create a mock `Body` with a simple flow. +fn goto_switchint<'a>() -> Body<'a> { + let mut blocks = MockBlocks::new(); + let start = blocks.call(None); + let goto = blocks.goto(Some(start)); + let switchint = blocks.switchint(Some(goto)); + let then_call = blocks.call(None); + let else_call = blocks.call(None); + blocks.set_branch(switchint, 0, then_call); + blocks.set_branch(switchint, 1, else_call); + blocks.return_(Some(then_call)); + blocks.return_(Some(else_call)); + + let mir_body = blocks.to_body(); + print_mir_graphviz("mir_goto_switchint", &mir_body); + /* Graphviz character plots created using: `graph-easy --as=boxart`: + ┌────────────────┐ + │ bb0: Call │ + └────────────────┘ + │ + │ + ▼ + ┌────────────────┐ + │ bb1: Goto │ + └────────────────┘ + │ + │ + ▼ + ┌─────────────┐ ┌────────────────┐ + │ bb4: Call │ ◀── │ bb2: SwitchInt │ + └─────────────┘ └────────────────┘ + │ │ + │ │ + ▼ ▼ + ┌─────────────┐ ┌────────────────┐ + │ bb6: Return │ │ bb3: Call │ + └─────────────┘ └────────────────┘ + │ + │ + ▼ + ┌────────────────┐ + │ bb5: Return │ + └────────────────┘ + */ + mir_body +} + +macro_rules! assert_successors { + ($basic_coverage_blocks:ident, $i:ident, [$($successor:ident),*]) => { + let mut successors = $basic_coverage_blocks.successors[$i].clone(); + successors.sort_unstable(); + assert_eq!(successors, vec![$($successor),*]); + } +} + +#[test] +fn test_covgraph_goto_switchint() { + let mir_body = goto_switchint(); + if false { + eprintln!("basic_blocks = {}", debug_basic_blocks(&mir_body)); + } + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + print_coverage_graphviz("covgraph_goto_switchint ", &mir_body, &basic_coverage_blocks); + /* + ┌──────────────┐ ┌─────────────────┐ + │ bcb2: Return │ ◀── │ bcb0: SwitchInt │ + └──────────────┘ └─────────────────┘ + │ + │ + ▼ + ┌─────────────────┐ + │ bcb1: Return │ + └─────────────────┘ + */ + assert_eq!( + basic_coverage_blocks.num_nodes(), + 3, + "basic_coverage_blocks: {:?}", + basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>() + ); + + let_bcb!(0); + let_bcb!(1); + let_bcb!(2); + + assert_successors!(basic_coverage_blocks, bcb0, [bcb1, bcb2]); + assert_successors!(basic_coverage_blocks, bcb1, []); + assert_successors!(basic_coverage_blocks, bcb2, []); +} + +/// Create a mock `Body` with a loop. +fn switchint_then_loop_else_return<'a>() -> Body<'a> { + let mut blocks = MockBlocks::new(); + let start = blocks.call(None); + let switchint = blocks.switchint(Some(start)); + let then_call = blocks.call(None); + blocks.set_branch(switchint, 0, then_call); + let backedge_goto = blocks.goto(Some(then_call)); + blocks.link(backedge_goto, switchint); + let else_return = blocks.return_(None); + blocks.set_branch(switchint, 1, else_return); + + let mir_body = blocks.to_body(); + print_mir_graphviz("mir_switchint_then_loop_else_return", &mir_body); + /* + ┌────────────────┐ + │ bb0: Call │ + └────────────────┘ + │ + │ + ▼ + ┌─────────────┐ ┌────────────────┐ + │ bb4: Return │ ◀── │ bb1: SwitchInt │ ◀┐ + └─────────────┘ └────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌────────────────┐ │ + │ bb2: Call │ │ + └────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌────────────────┐ │ + │ bb3: Goto │ ─┘ + └────────────────┘ + */ + mir_body +} + +#[test] +fn test_covgraph_switchint_then_loop_else_return() { + let mir_body = switchint_then_loop_else_return(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + print_coverage_graphviz( + "covgraph_switchint_then_loop_else_return", + &mir_body, + &basic_coverage_blocks, + ); + /* + ┌─────────────────┐ + │ bcb0: Call │ + └─────────────────┘ + │ + │ + ▼ + ┌────────────┐ ┌─────────────────┐ + │ bcb3: Goto │ ◀── │ bcb1: SwitchInt │ ◀┐ + └────────────┘ └─────────────────┘ │ + │ │ │ + │ │ │ + │ ▼ │ + │ ┌─────────────────┐ │ + │ │ bcb2: Return │ │ + │ └─────────────────┘ │ + │ │ + └─────────────────────────────────────┘ + */ + assert_eq!( + basic_coverage_blocks.num_nodes(), + 4, + "basic_coverage_blocks: {:?}", + basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>() + ); + + let_bcb!(0); + let_bcb!(1); + let_bcb!(2); + let_bcb!(3); + + assert_successors!(basic_coverage_blocks, bcb0, [bcb1]); + assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]); + assert_successors!(basic_coverage_blocks, bcb2, []); + assert_successors!(basic_coverage_blocks, bcb3, [bcb1]); +} + +/// Create a mock `Body` with nested loops. +fn switchint_loop_then_inner_loop_else_break<'a>() -> Body<'a> { + let mut blocks = MockBlocks::new(); + let start = blocks.call(None); + let switchint = blocks.switchint(Some(start)); + let then_call = blocks.call(None); + blocks.set_branch(switchint, 0, then_call); + let else_return = blocks.return_(None); + blocks.set_branch(switchint, 1, else_return); + + let inner_start = blocks.call(Some(then_call)); + let inner_switchint = blocks.switchint(Some(inner_start)); + let inner_then_call = blocks.call(None); + blocks.set_branch(inner_switchint, 0, inner_then_call); + let inner_backedge_goto = blocks.goto(Some(inner_then_call)); + blocks.link(inner_backedge_goto, inner_switchint); + let inner_else_break_goto = blocks.goto(None); + blocks.set_branch(inner_switchint, 1, inner_else_break_goto); + + let backedge_goto = blocks.goto(Some(inner_else_break_goto)); + blocks.link(backedge_goto, switchint); + + let mir_body = blocks.to_body(); + print_mir_graphviz("mir_switchint_loop_then_inner_loop_else_break", &mir_body); + /* + ┌────────────────┐ + │ bb0: Call │ + └────────────────┘ + │ + │ + ▼ + ┌─────────────┐ ┌────────────────┐ + │ bb3: Return │ ◀── │ bb1: SwitchInt │ ◀─────┐ + └─────────────┘ └────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌────────────────┐ │ + │ bb2: Call │ │ + └────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌────────────────┐ │ + │ bb4: Call │ │ + └────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌─────────────┐ ┌────────────────┐ │ + │ bb8: Goto │ ◀── │ bb5: SwitchInt │ ◀┐ │ + └─────────────┘ └────────────────┘ │ │ + │ │ │ │ + │ │ │ │ + ▼ ▼ │ │ + ┌─────────────┐ ┌────────────────┐ │ │ + │ bb9: Goto │ ─┐ │ bb6: Call │ │ │ + └─────────────┘ │ └────────────────┘ │ │ + │ │ │ │ + │ │ │ │ + │ ▼ │ │ + │ ┌────────────────┐ │ │ + │ │ bb7: Goto │ ─┘ │ + │ └────────────────┘ │ + │ │ + └───────────────────────────┘ + */ + mir_body +} + +#[test] +fn test_covgraph_switchint_loop_then_inner_loop_else_break() { + let mir_body = switchint_loop_then_inner_loop_else_break(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + print_coverage_graphviz( + "covgraph_switchint_loop_then_inner_loop_else_break", + &mir_body, + &basic_coverage_blocks, + ); + /* + ┌─────────────────┐ + │ bcb0: Call │ + └─────────────────┘ + │ + │ + ▼ + ┌──────────────┐ ┌─────────────────┐ + │ bcb2: Return │ ◀── │ bcb1: SwitchInt │ ◀┐ + └──────────────┘ └─────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌─────────────────┐ │ + │ bcb3: Call │ │ + └─────────────────┘ │ + │ │ + │ │ + ▼ │ + ┌──────────────┐ ┌─────────────────┐ │ + │ bcb6: Goto │ ◀── │ bcb4: SwitchInt │ ◀┼────┐ + └──────────────┘ └─────────────────┘ │ │ + │ │ │ │ + │ │ │ │ + │ ▼ │ │ + │ ┌─────────────────┐ │ │ + │ │ bcb5: Goto │ ─┘ │ + │ └─────────────────┘ │ + │ │ + └────────────────────────────────────────────┘ + */ + assert_eq!( + basic_coverage_blocks.num_nodes(), + 7, + "basic_coverage_blocks: {:?}", + basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>() + ); + + let_bcb!(0); + let_bcb!(1); + let_bcb!(2); + let_bcb!(3); + let_bcb!(4); + let_bcb!(5); + let_bcb!(6); + + assert_successors!(basic_coverage_blocks, bcb0, [bcb1]); + assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]); + assert_successors!(basic_coverage_blocks, bcb2, []); + assert_successors!(basic_coverage_blocks, bcb3, [bcb4]); + assert_successors!(basic_coverage_blocks, bcb4, [bcb5, bcb6]); + assert_successors!(basic_coverage_blocks, bcb5, [bcb1]); + assert_successors!(basic_coverage_blocks, bcb6, [bcb4]); +} + +#[test] +fn test_find_loop_backedges_none() { + let mir_body = goto_switchint(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + if false { + eprintln!( + "basic_coverage_blocks = {:?}", + basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>() + ); + eprintln!("successors = {:?}", basic_coverage_blocks.successors); + } + let backedges = graph::find_loop_backedges(&basic_coverage_blocks); + assert_eq!( + backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(), + 0, + "backedges: {:?}", + backedges + ); +} + +#[test] +fn test_find_loop_backedges_one() { + let mir_body = switchint_then_loop_else_return(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + let backedges = graph::find_loop_backedges(&basic_coverage_blocks); + assert_eq!( + backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(), + 1, + "backedges: {:?}", + backedges + ); + + let_bcb!(1); + let_bcb!(3); + + assert_eq!(backedges[bcb1], vec![bcb3]); +} + +#[test] +fn test_find_loop_backedges_two() { + let mir_body = switchint_loop_then_inner_loop_else_break(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + let backedges = graph::find_loop_backedges(&basic_coverage_blocks); + assert_eq!( + backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(), + 2, + "backedges: {:?}", + backedges + ); + + let_bcb!(1); + let_bcb!(4); + let_bcb!(5); + let_bcb!(6); + + assert_eq!(backedges[bcb1], vec![bcb5]); + assert_eq!(backedges[bcb4], vec![bcb6]); +} + +#[test] +fn test_traverse_coverage_with_loops() { + let mir_body = switchint_loop_then_inner_loop_else_break(); + let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + let mut traversed_in_order = Vec::new(); + let mut traversal = graph::TraverseCoverageGraphWithLoops::new(&basic_coverage_blocks); + while let Some(bcb) = traversal.next(&basic_coverage_blocks) { + traversed_in_order.push(bcb); + } + + let_bcb!(6); + + // bcb0 is visited first. Then bcb1 starts the first loop, and all remaining nodes, *except* + // bcb6 are inside the first loop. + assert_eq!( + *traversed_in_order.last().expect("should have elements"), + bcb6, + "bcb6 should not be visited until all nodes inside the first loop have been visited" + ); +} + +fn synthesize_body_span_from_terminators(mir_body: &Body<'_>) -> Span { + let mut some_span: Option<Span> = None; + for (_, data) in mir_body.basic_blocks().iter_enumerated() { + let term_span = data.terminator().source_info.span; + if let Some(span) = some_span.as_mut() { + *span = span.to(term_span); + } else { + some_span = Some(term_span) + } + } + some_span.expect("body must have at least one BasicBlock") +} + +#[test] +fn test_make_bcb_counters() { + rustc_span::create_default_session_globals_then(|| { + let mir_body = goto_switchint(); + let body_span = synthesize_body_span_from_terminators(&mir_body); + let mut basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body); + let mut coverage_spans = Vec::new(); + for (bcb, data) in basic_coverage_blocks.iter_enumerated() { + if let Some(span) = spans::filtered_terminator_span(data.terminator(&mir_body)) { + coverage_spans.push(spans::CoverageSpan::for_terminator( + spans::function_source_span(span, body_span), + span, + bcb, + data.last_bb(), + )); + } + } + let mut coverage_counters = counters::CoverageCounters::new(0); + let intermediate_expressions = coverage_counters + .make_bcb_counters(&mut basic_coverage_blocks, &coverage_spans) + .expect("should be Ok"); + assert_eq!(intermediate_expressions.len(), 0); + + let_bcb!(1); + assert_eq!( + 1, // coincidentally, bcb1 has a `Counter` with id = 1 + match basic_coverage_blocks[bcb1].counter().expect("should have a counter") { + CoverageKind::Counter { id, .. } => id, + _ => panic!("expected a Counter"), + } + .as_u32() + ); + + let_bcb!(2); + assert_eq!( + 2, // coincidentally, bcb2 has a `Counter` with id = 2 + match basic_coverage_blocks[bcb2].counter().expect("should have a counter") { + CoverageKind::Counter { id, .. } => id, + _ => panic!("expected a Counter"), + } + .as_u32() + ); + }); +} |