1 //! This crate hosts a selection of "unit tests" for components of the `InstrumentCoverage` MIR
5 //! ./x.py test --keep-stage 1 compiler/rustc_mir --test-args '--show-output coverage'
8 //! The tests construct a few "mock" objects, as needed, to support the `InstrumentCoverage`
9 //! functions and algorithms. Mocked objects include instances of `mir::Body`; including
10 //! `Terminator`s of various `kind`s, and `Span` objects. Some functions used by or used on
11 //! real, runtime versions of these mocked-up objects have constraints (such as cross-thread
12 //! limitations) and deep dependencies on other elements of the full Rust compiler (which is
13 //! *not* constructed or mocked for these tests).
15 //! Of particular note, attempting to simply print elements of the `mir::Body` with default
16 //! `Debug` formatting can fail because some `Debug` format implementations require the
17 //! `TyCtxt`, obtained via a static global variable that is *not* set for these tests.
18 //! Initializing the global type context is prohibitively complex for the scope and scale of these
19 //! tests (essentially requiring initializing the entire compiler).
21 //! Also note, some basic features of `Span` also rely on the `Span`s own "session globals", which
22 //! are unrelated to the `TyCtxt` global. Without initializing the `Span` session globals, some
23 //! basic, coverage-specific features would be impossible to test, but thankfully initializing these
24 //! globals is comparatively simpler. The easiest way is to wrap the test in a closure argument
25 //! to: `rustc_span::create_default_session_globals_then(|| { test_here(); })`.
32 use coverage_test_macros::let_bcb;
34 use itertools::Itertools;
35 use rustc_data_structures::graph::WithNumNodes;
36 use rustc_data_structures::graph::WithSuccessors;
37 use rustc_index::vec::{Idx, IndexVec};
38 use rustc_middle::mir::coverage::CoverageKind;
39 use rustc_middle::mir::*;
40 use rustc_middle::ty::{self, Ty, TyCtxt};
41 use rustc_span::{self, BytePos, Pos, Span, DUMMY_SP};
43 // All `TEMP_BLOCK` targets should be replaced before calling `to_body() -> mir::Body`.
44 const TEMP_BLOCK: BasicBlock = BasicBlock::MAX;
46 struct MockBlocks<'tcx> {
47 blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
48 dummy_place: Place<'tcx>,
53 impl<'tcx> MockBlocks<'tcx> {
56 blocks: IndexVec::new(),
57 dummy_place: Place { local: RETURN_PLACE, projection: ty::List::empty() },
59 bool_ty: TyCtxt::BOOL_TY_FOR_UNIT_TESTING,
63 fn new_temp(&mut self) -> Local {
64 let index = self.next_local;
69 fn push(&mut self, kind: TerminatorKind<'tcx>) -> BasicBlock {
70 let next_lo = if let Some(last) = self.blocks.last() {
71 self.blocks[last].terminator().source_info.span.hi()
75 let next_hi = next_lo + BytePos(1);
76 self.blocks.push(BasicBlockData {
78 terminator: Some(Terminator {
79 source_info: SourceInfo::outermost(Span::with_root_ctxt(next_lo, next_hi)),
86 fn link(&mut self, from_block: BasicBlock, to_block: BasicBlock) {
87 match self.blocks[from_block].terminator_mut().kind {
88 TerminatorKind::Assert { ref mut target, .. }
89 | TerminatorKind::Call { target: Some(ref mut target), .. }
90 | TerminatorKind::Drop { ref mut target, .. }
91 | TerminatorKind::DropAndReplace { ref mut target, .. }
92 | TerminatorKind::FalseEdge { real_target: ref mut target, .. }
93 | TerminatorKind::FalseUnwind { real_target: ref mut target, .. }
94 | TerminatorKind::Goto { ref mut target }
95 | TerminatorKind::InlineAsm { destination: Some(ref mut target), .. }
96 | TerminatorKind::Yield { resume: ref mut target, .. } => *target = to_block,
97 ref invalid => bug!("Invalid from_block: {:?}", invalid),
103 some_from_block: Option<BasicBlock>,
104 to_kind: TerminatorKind<'tcx>,
106 let new_block = self.push(to_kind);
107 if let Some(from_block) = some_from_block {
108 self.link(from_block, new_block);
113 fn set_branch(&mut self, switchint: BasicBlock, branch_index: usize, to_block: BasicBlock) {
114 match self.blocks[switchint].terminator_mut().kind {
115 TerminatorKind::SwitchInt { ref mut targets, .. } => {
116 let mut branches = targets.iter().collect::<Vec<_>>();
117 let otherwise = if branch_index == branches.len() {
120 let old_otherwise = targets.otherwise();
121 if branch_index > branches.len() {
122 branches.push((branches.len() as u128, old_otherwise));
123 while branches.len() < branch_index {
124 branches.push((branches.len() as u128, TEMP_BLOCK));
128 branches[branch_index] = (branch_index as u128, to_block);
132 *targets = SwitchTargets::new(branches.into_iter(), otherwise);
134 ref invalid => bug!("Invalid BasicBlock kind or no to_block: {:?}", invalid),
138 fn call(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
141 TerminatorKind::Call {
142 func: Operand::Copy(self.dummy_place.clone()),
144 destination: self.dummy_place.clone(),
145 target: Some(TEMP_BLOCK),
147 from_hir_call: false,
153 fn goto(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
154 self.add_block_from(some_from_block, TerminatorKind::Goto { target: TEMP_BLOCK })
157 fn switchint(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
158 let switchint_kind = TerminatorKind::SwitchInt {
159 discr: Operand::Move(Place::from(self.new_temp())),
160 switch_ty: self.bool_ty, // just a dummy value
161 targets: SwitchTargets::static_if(0, TEMP_BLOCK, TEMP_BLOCK),
163 self.add_block_from(some_from_block, switchint_kind)
166 fn return_(&mut self, some_from_block: Option<BasicBlock>) -> BasicBlock {
167 self.add_block_from(some_from_block, TerminatorKind::Return)
170 fn to_body(self) -> Body<'tcx> {
171 Body::new_cfg_only(self.blocks)
175 fn debug_basic_blocks<'tcx>(mir_body: &Body<'tcx>) -> String {
182 let term = &data.terminator();
183 let kind = &term.kind;
184 let span = term.source_info.span;
185 let sp = format!("(span:{},{})", span.lo().to_u32(), span.hi().to_u32());
187 TerminatorKind::Assert { target, .. }
188 | TerminatorKind::Call { target: Some(target), .. }
189 | TerminatorKind::Drop { target, .. }
190 | TerminatorKind::DropAndReplace { target, .. }
191 | TerminatorKind::FalseEdge { real_target: target, .. }
192 | TerminatorKind::FalseUnwind { real_target: target, .. }
193 | TerminatorKind::Goto { target }
194 | TerminatorKind::InlineAsm { destination: Some(target), .. }
195 | TerminatorKind::Yield { resume: target, .. } => {
196 format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), target)
198 TerminatorKind::SwitchInt { targets, .. } => {
199 format!("{}{:?}:{} -> {:?}", sp, bb, debug::term_type(kind), targets)
201 _ => format!("{}{:?}:{}", sp, bb, debug::term_type(kind)),
208 static PRINT_GRAPHS: bool = false;
210 fn print_mir_graphviz(name: &str, mir_body: &Body<'_>) {
213 "digraph {} {{\n{}\n}}",
220 " {:?} [label=\"{:?}: {}\"];\n{}",
223 debug::term_type(&data.terminator().kind),
227 .map(|successor| { format!(" {:?} -> {:?};", bb, successor) })
236 fn print_coverage_graphviz(
239 basic_coverage_blocks: &graph::CoverageGraph,
243 "digraph {} {{\n{}\n}}",
245 basic_coverage_blocks
247 .map(|(bcb, bcb_data)| {
249 " {:?} [label=\"{:?}: {}\"];\n{}",
252 debug::term_type(&bcb_data.terminator(mir_body).kind),
253 basic_coverage_blocks
255 .map(|successor| { format!(" {:?} -> {:?};", bcb, successor) })
264 /// Create a mock `Body` with a simple flow.
265 fn goto_switchint<'a>() -> Body<'a> {
266 let mut blocks = MockBlocks::new();
267 let start = blocks.call(None);
268 let goto = blocks.goto(Some(start));
269 let switchint = blocks.switchint(Some(goto));
270 let then_call = blocks.call(None);
271 let else_call = blocks.call(None);
272 blocks.set_branch(switchint, 0, then_call);
273 blocks.set_branch(switchint, 1, else_call);
274 blocks.return_(Some(then_call));
275 blocks.return_(Some(else_call));
277 let mir_body = blocks.to_body();
278 print_mir_graphviz("mir_goto_switchint", &mir_body);
279 /* Graphviz character plots created using: `graph-easy --as=boxart`:
292 ┌─────────────┐ ┌────────────────┐
293 │ bb4: Call │ ◀── │ bb2: SwitchInt │
294 └─────────────┘ └────────────────┘
298 ┌─────────────┐ ┌────────────────┐
299 │ bb6: Return │ │ bb3: Call │
300 └─────────────┘ └────────────────┘
311 macro_rules! assert_successors {
312 ($basic_coverage_blocks:ident, $i:ident, [$($successor:ident),*]) => {
313 let mut successors = $basic_coverage_blocks.successors[$i].clone();
314 successors.sort_unstable();
315 assert_eq!(successors, vec![$($successor),*]);
320 fn test_covgraph_goto_switchint() {
321 let mir_body = goto_switchint();
323 eprintln!("basic_blocks = {}", debug_basic_blocks(&mir_body));
325 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
326 print_coverage_graphviz("covgraph_goto_switchint ", &mir_body, &basic_coverage_blocks);
328 ┌──────────────┐ ┌─────────────────┐
329 │ bcb2: Return │ ◀── │ bcb0: SwitchInt │
330 └──────────────┘ └─────────────────┘
339 basic_coverage_blocks.num_nodes(),
341 "basic_coverage_blocks: {:?}",
342 basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
349 assert_successors!(basic_coverage_blocks, bcb0, [bcb1, bcb2]);
350 assert_successors!(basic_coverage_blocks, bcb1, []);
351 assert_successors!(basic_coverage_blocks, bcb2, []);
354 /// Create a mock `Body` with a loop.
355 fn switchint_then_loop_else_return<'a>() -> Body<'a> {
356 let mut blocks = MockBlocks::new();
357 let start = blocks.call(None);
358 let switchint = blocks.switchint(Some(start));
359 let then_call = blocks.call(None);
360 blocks.set_branch(switchint, 0, then_call);
361 let backedge_goto = blocks.goto(Some(then_call));
362 blocks.link(backedge_goto, switchint);
363 let else_return = blocks.return_(None);
364 blocks.set_branch(switchint, 1, else_return);
366 let mir_body = blocks.to_body();
367 print_mir_graphviz("mir_switchint_then_loop_else_return", &mir_body);
375 ┌─────────────┐ ┌────────────────┐
376 │ bb4: Return │ ◀── │ bb1: SwitchInt │ ◀┐
377 └─────────────┘ └────────────────┘ │
395 fn test_covgraph_switchint_then_loop_else_return() {
396 let mir_body = switchint_then_loop_else_return();
397 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
398 print_coverage_graphviz(
399 "covgraph_switchint_then_loop_else_return",
401 &basic_coverage_blocks,
410 ┌────────────┐ ┌─────────────────┐
411 │ bcb3: Goto │ ◀── │ bcb1: SwitchInt │ ◀┐
412 └────────────┘ └─────────────────┘ │
416 │ ┌─────────────────┐ │
418 │ └─────────────────┘ │
420 └─────────────────────────────────────┘
423 basic_coverage_blocks.num_nodes(),
425 "basic_coverage_blocks: {:?}",
426 basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
434 assert_successors!(basic_coverage_blocks, bcb0, [bcb1]);
435 assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]);
436 assert_successors!(basic_coverage_blocks, bcb2, []);
437 assert_successors!(basic_coverage_blocks, bcb3, [bcb1]);
440 /// Create a mock `Body` with nested loops.
441 fn switchint_loop_then_inner_loop_else_break<'a>() -> Body<'a> {
442 let mut blocks = MockBlocks::new();
443 let start = blocks.call(None);
444 let switchint = blocks.switchint(Some(start));
445 let then_call = blocks.call(None);
446 blocks.set_branch(switchint, 0, then_call);
447 let else_return = blocks.return_(None);
448 blocks.set_branch(switchint, 1, else_return);
450 let inner_start = blocks.call(Some(then_call));
451 let inner_switchint = blocks.switchint(Some(inner_start));
452 let inner_then_call = blocks.call(None);
453 blocks.set_branch(inner_switchint, 0, inner_then_call);
454 let inner_backedge_goto = blocks.goto(Some(inner_then_call));
455 blocks.link(inner_backedge_goto, inner_switchint);
456 let inner_else_break_goto = blocks.goto(None);
457 blocks.set_branch(inner_switchint, 1, inner_else_break_goto);
459 let backedge_goto = blocks.goto(Some(inner_else_break_goto));
460 blocks.link(backedge_goto, switchint);
462 let mir_body = blocks.to_body();
463 print_mir_graphviz("mir_switchint_loop_then_inner_loop_else_break", &mir_body);
471 ┌─────────────┐ ┌────────────────┐
472 │ bb3: Return │ ◀── │ bb1: SwitchInt │ ◀─────┐
473 └─────────────┘ └────────────────┘ │
489 ┌─────────────┐ ┌────────────────┐ │
490 │ bb8: Goto │ ◀── │ bb5: SwitchInt │ ◀┐ │
491 └─────────────┘ └────────────────┘ │ │
495 ┌─────────────┐ ┌────────────────┐ │ │
496 │ bb9: Goto │ ─┐ │ bb6: Call │ │ │
497 └─────────────┘ │ └────────────────┘ │ │
501 │ ┌────────────────┐ │ │
503 │ └────────────────┘ │
505 └───────────────────────────┘
511 fn test_covgraph_switchint_loop_then_inner_loop_else_break() {
512 let mir_body = switchint_loop_then_inner_loop_else_break();
513 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
514 print_coverage_graphviz(
515 "covgraph_switchint_loop_then_inner_loop_else_break",
517 &basic_coverage_blocks,
526 ┌──────────────┐ ┌─────────────────┐
527 │ bcb2: Return │ ◀── │ bcb1: SwitchInt │ ◀┐
528 └──────────────┘ └─────────────────┘ │
532 ┌─────────────────┐ │
534 └─────────────────┘ │
538 ┌──────────────┐ ┌─────────────────┐ │
539 │ bcb6: Goto │ ◀── │ bcb4: SwitchInt │ ◀┼────┐
540 └──────────────┘ └─────────────────┘ │ │
544 │ ┌─────────────────┐ │ │
545 │ │ bcb5: Goto │ ─┘ │
546 │ └─────────────────┘ │
548 └────────────────────────────────────────────┘
551 basic_coverage_blocks.num_nodes(),
553 "basic_coverage_blocks: {:?}",
554 basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
565 assert_successors!(basic_coverage_blocks, bcb0, [bcb1]);
566 assert_successors!(basic_coverage_blocks, bcb1, [bcb2, bcb3]);
567 assert_successors!(basic_coverage_blocks, bcb2, []);
568 assert_successors!(basic_coverage_blocks, bcb3, [bcb4]);
569 assert_successors!(basic_coverage_blocks, bcb4, [bcb5, bcb6]);
570 assert_successors!(basic_coverage_blocks, bcb5, [bcb1]);
571 assert_successors!(basic_coverage_blocks, bcb6, [bcb4]);
575 fn test_find_loop_backedges_none() {
576 let mir_body = goto_switchint();
577 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
580 "basic_coverage_blocks = {:?}",
581 basic_coverage_blocks.iter_enumerated().collect::<Vec<_>>()
583 eprintln!("successors = {:?}", basic_coverage_blocks.successors);
585 let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
587 backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
595 fn test_find_loop_backedges_one() {
596 let mir_body = switchint_then_loop_else_return();
597 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
598 let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
600 backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
609 assert_eq!(backedges[bcb1], vec![bcb3]);
613 fn test_find_loop_backedges_two() {
614 let mir_body = switchint_loop_then_inner_loop_else_break();
615 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
616 let backedges = graph::find_loop_backedges(&basic_coverage_blocks);
618 backedges.iter_enumerated().map(|(_bcb, backedges)| backedges.len()).sum::<usize>(),
629 assert_eq!(backedges[bcb1], vec![bcb5]);
630 assert_eq!(backedges[bcb4], vec![bcb6]);
634 fn test_traverse_coverage_with_loops() {
635 let mir_body = switchint_loop_then_inner_loop_else_break();
636 let basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
637 let mut traversed_in_order = Vec::new();
638 let mut traversal = graph::TraverseCoverageGraphWithLoops::new(&basic_coverage_blocks);
639 while let Some(bcb) = traversal.next(&basic_coverage_blocks) {
640 traversed_in_order.push(bcb);
645 // bcb0 is visited first. Then bcb1 starts the first loop, and all remaining nodes, *except*
646 // bcb6 are inside the first loop.
648 *traversed_in_order.last().expect("should have elements"),
650 "bcb6 should not be visited until all nodes inside the first loop have been visited"
654 fn synthesize_body_span_from_terminators(mir_body: &Body<'_>) -> Span {
655 let mut some_span: Option<Span> = None;
656 for (_, data) in mir_body.basic_blocks.iter_enumerated() {
657 let term_span = data.terminator().source_info.span;
658 if let Some(span) = some_span.as_mut() {
659 *span = span.to(term_span);
661 some_span = Some(term_span)
664 some_span.expect("body must have at least one BasicBlock")
668 fn test_make_bcb_counters() {
669 rustc_span::create_default_session_globals_then(|| {
670 let mir_body = goto_switchint();
671 let body_span = synthesize_body_span_from_terminators(&mir_body);
672 let mut basic_coverage_blocks = graph::CoverageGraph::from_mir(&mir_body);
673 let mut coverage_spans = Vec::new();
674 for (bcb, data) in basic_coverage_blocks.iter_enumerated() {
675 if let Some(span) = spans::filtered_terminator_span(data.terminator(&mir_body)) {
676 coverage_spans.push(spans::CoverageSpan::for_terminator(
677 spans::function_source_span(span, body_span),
684 let mut coverage_counters = counters::CoverageCounters::new(0);
685 let intermediate_expressions = coverage_counters
686 .make_bcb_counters(&mut basic_coverage_blocks, &coverage_spans)
687 .expect("should be Ok");
688 assert_eq!(intermediate_expressions.len(), 0);
692 1, // coincidentally, bcb1 has a `Counter` with id = 1
693 match basic_coverage_blocks[bcb1].counter().expect("should have a counter") {
694 CoverageKind::Counter { id, .. } => id,
695 _ => panic!("expected a Counter"),
702 2, // coincidentally, bcb2 has a `Counter` with id = 2
703 match basic_coverage_blocks[bcb2].counter().expect("should have a counter") {
704 CoverageKind::Counter { id, .. } => id,
705 _ => panic!("expected a Counter"),