compiler/rustc_mir_transform/src/coverage/debug.rs

   1 //! The `InstrumentCoverage` MIR pass implementation includes debugging tools and options
   2 //! to help developers understand and/or improve the analysis and instrumentation of a MIR.
   3 //!
   4 //! To enable coverage, include the rustc command line option:
   5 //!
   6 //!   * `-C instrument-coverage`
   7 //!
   8 //! MIR Dump Files, with additional `CoverageGraph` graphviz and `CoverageSpan` spanview
   9 //! ------------------------------------------------------------------------------------
  10 //!
  11 //! Additional debugging options include:
  12 //!
  13 //!   * `-Z dump-mir=InstrumentCoverage` - Generate `.mir` files showing the state of the MIR,
  14 //!     before and after the `InstrumentCoverage` pass, for each compiled function.
  15 //!
  16 //!   * `-Z dump-mir-graphviz` - If `-Z dump-mir` is also enabled for the current MIR node path,
  17 //!     each MIR dump is accompanied by a before-and-after graphical view of the MIR, in Graphviz
  18 //!     `.dot` file format (which can be visually rendered as a graph using any of a number of free
  19 //!     Graphviz viewers and IDE extensions).
  20 //!
  21 //!     For the `InstrumentCoverage` pass, this option also enables generation of an additional
  22 //!     Graphviz `.dot` file for each function, rendering the `CoverageGraph`: the control flow
  23 //!     graph (CFG) of `BasicCoverageBlocks` (BCBs), as nodes, internally labeled to show the
  24 //!     `CoverageSpan`-based MIR elements each BCB represents (`BasicBlock`s, `Statement`s and
  25 //!     `Terminator`s), assigned coverage counters and/or expressions, and edge counters, as needed.
  26 //!
  27 //!     (Note the additional option, `-Z graphviz-dark-mode`, can be added, to change the rendered
  28 //!     output from its default black-on-white background to a dark color theme, if desired.)
  29 //!
  30 //!   * `-Z dump-mir-spanview` - If `-Z dump-mir` is also enabled for the current MIR node path,
  31 //!     each MIR dump is accompanied by a before-and-after `.html` document showing the function's
  32 //!     original source code, highlighted by it's MIR spans, at the `statement`-level (by default),
  33 //!     `terminator` only, or encompassing span for the `Terminator` plus all `Statement`s, in each
  34 //!     `block` (`BasicBlock`).
  35 //!
  36 //!     For the `InstrumentCoverage` pass, this option also enables generation of an additional
  37 //!     spanview `.html` file for each function, showing the aggregated `CoverageSpan`s that will
  38 //!     require counters (or counter expressions) for accurate coverage analysis.
  39 //!
  40 //! Debug Logging
  41 //! -------------
  42 //!
  43 //! The `InstrumentCoverage` pass includes debug logging messages at various phases and decision
  44 //! points, which can be enabled via environment variable:
  45 //!
  46 //! ```shell
  47 //! RUSTC_LOG=rustc_mir_transform::transform::coverage=debug
  48 //! ```
  49 //!
  50 //! Other module paths with coverage-related debug logs may also be of interest, particularly for
  51 //! debugging the coverage map data, injected as global variables in the LLVM IR (during rustc's
  52 //! code generation pass). For example:
  53 //!
  54 //! ```shell
  55 //! RUSTC_LOG=rustc_mir_transform::transform::coverage,rustc_codegen_ssa::coverageinfo,rustc_codegen_llvm::coverageinfo=debug
  56 //! ```
  57 //!
  58 //! Coverage Debug Options
  59 //! ---------------------------------
  60 //!
  61 //! Additional debugging options can be enabled using the environment variable:
  62 //!
  63 //! ```shell
  64 //! RUSTC_COVERAGE_DEBUG_OPTIONS=<options>
  65 //! ```
  66 //!
  67 //! These options are comma-separated, and specified in the format `option-name=value`. For example:
  68 //!
  69 //! ```shell
  70 //! $ RUSTC_COVERAGE_DEBUG_OPTIONS=counter-format=id+operation,allow-unused-expressions=yes cargo build
  71 //! ```
  72 //!
  73 //! Coverage debug options include:
  74 //!
  75 //!   * `allow-unused-expressions=yes` or `no` (default: `no`)
  76 //!
  77 //!     The `InstrumentCoverage` algorithms _should_ only create and assign expressions to a
  78 //!     `BasicCoverageBlock`, or an incoming edge, if that expression is either (a) required to
  79 //!     count a `CoverageSpan`, or (b) a dependency of some other required counter expression.
  80 //!
  81 //!     If an expression is generated that does not map to a `CoverageSpan` or dependency, this
  82 //!     probably indicates there was a bug in the algorithm that creates and assigns counters
  83 //!     and expressions.
  84 //!
  85 //!     When this kind of bug is encountered, the rustc compiler will panic by default. Setting:
  86 //!     `allow-unused-expressions=yes` will log a warning message instead of panicking (effectively
  87 //!     ignoring the unused expressions), which may be helpful when debugging the root cause of
  88 //!     the problem.
  89 //!
  90 //!   * `counter-format=<choices>`, where `<choices>` can be any plus-separated combination of `id`,
  91 //!     `block`, and/or `operation` (default: `block+operation`)
  92 //!
  93 //!     This option effects both the `CoverageGraph` (graphviz `.dot` files) and debug logging, when
  94 //!     generating labels for counters and expressions.
  95 //!
  96 //!     Depending on the values and combinations, counters can be labeled by:
  97 //!
  98 //!       * `id` - counter or expression ID (ascending counter IDs, starting at 1, or descending
  99 //!         expression IDs, starting at `u32:MAX`)
 100 //!       * `block` - the `BasicCoverageBlock` label (for example, `bcb0`) or edge label (for
 101 //!         example `bcb0->bcb1`), for counters or expressions assigned to count a
 102 //!         `BasicCoverageBlock` or edge. Intermediate expressions (not directly associated with
 103 //!         a BCB or edge) will be labeled by their expression ID, unless `operation` is also
 104 //!         specified.
 105 //!       * `operation` - applied to expressions only, labels include the left-hand-side counter
 106 //!         or expression label (lhs operand), the operator (`+` or `-`), and the right-hand-side
 107 //!         counter or expression (rhs operand). Expression operand labels are generated
 108 //!         recursively, generating labels with nested operations, enclosed in parentheses
 109 //!         (for example: `bcb2 + (bcb0 - bcb1)`).
 110
 111 use super::graph::{BasicCoverageBlock, BasicCoverageBlockData, CoverageGraph};
 112 use super::spans::CoverageSpan;
 113
 114 use itertools::Itertools;
 115 use rustc_middle::mir::create_dump_file;
 116 use rustc_middle::mir::generic_graphviz::GraphvizWriter;
 117 use rustc_middle::mir::spanview::{self, SpanViewable};
 118
 119 use rustc_data_structures::fx::FxHashMap;
 120 use rustc_middle::mir::coverage::*;
 121 use rustc_middle::mir::{self, BasicBlock, TerminatorKind};
 122 use rustc_middle::ty::TyCtxt;
 123 use rustc_span::Span;
 124
 125 use std::iter;
 126 use std::lazy::SyncOnceCell;
 127
 128 pub const NESTED_INDENT: &str = "    ";
 129
 130 const RUSTC_COVERAGE_DEBUG_OPTIONS: &str = "RUSTC_COVERAGE_DEBUG_OPTIONS";
 131
 132 pub(super) fn debug_options<'a>() -> &'a DebugOptions {
 133     static DEBUG_OPTIONS: SyncOnceCell<DebugOptions> = SyncOnceCell::new();
 134
 135     &DEBUG_OPTIONS.get_or_init(DebugOptions::from_env)
 136 }
 137
 138 /// Parses and maintains coverage-specific debug options captured from the environment variable
 139 /// "RUSTC_COVERAGE_DEBUG_OPTIONS", if set.
 140 #[derive(Debug, Clone)]
 141 pub(super) struct DebugOptions {
 142     pub allow_unused_expressions: bool,
 143     counter_format: ExpressionFormat,
 144 }
 145
 146 impl DebugOptions {
 147     fn from_env() -> Self {
 148         let mut allow_unused_expressions = true;
 149         let mut counter_format = ExpressionFormat::default();
 150
 151         if let Ok(env_debug_options) = std::env::var(RUSTC_COVERAGE_DEBUG_OPTIONS) {
 152             for setting_str in env_debug_options.replace(' ', "").replace('-', "_").split(',') {
 153                 let (option, value) = match setting_str.split_once('=') {
 154                     None => (setting_str, None),
 155                     Some((k, v)) => (k, Some(v)),
 156                 };
 157                 match option {
 158                     "allow_unused_expressions" => {
 159                         allow_unused_expressions = bool_option_val(option, value);
 160                         debug!(
 161                             "{} env option `allow_unused_expressions` is set to {}",
 162                             RUSTC_COVERAGE_DEBUG_OPTIONS, allow_unused_expressions
 163                         );
 164                     }
 165                     "counter_format" => {
 166                         match value {
 167                             None => {
 168                                 bug!(
 169                                     "`{}` option in environment variable {} requires one or more \
 170                                     plus-separated choices (a non-empty subset of \
 171                                     `id+block+operation`)",
 172                                     option,
 173                                     RUSTC_COVERAGE_DEBUG_OPTIONS
 174                                 );
 175                             }
 176                             Some(val) => {
 177                                 counter_format = counter_format_option_val(val);
 178                                 debug!(
 179                                     "{} env option `counter_format` is set to {:?}",
 180                                     RUSTC_COVERAGE_DEBUG_OPTIONS, counter_format
 181                                 );
 182                             }
 183                         };
 184                     }
 185                     _ => bug!(
 186                         "Unsupported setting `{}` in environment variable {}",
 187                         option,
 188                         RUSTC_COVERAGE_DEBUG_OPTIONS
 189                     ),
 190                 };
 191             }
 192         }
 193
 194         Self { allow_unused_expressions, counter_format }
 195     }
 196 }
 197
 198 fn bool_option_val(option: &str, some_strval: Option<&str>) -> bool {
 199     if let Some(val) = some_strval {
 200         if vec!["yes", "y", "on", "true"].contains(&val) {
 201             true
 202         } else if vec!["no", "n", "off", "false"].contains(&val) {
 203             false
 204         } else {
 205             bug!(
 206                 "Unsupported value `{}` for option `{}` in environment variable {}",
 207                 option,
 208                 val,
 209                 RUSTC_COVERAGE_DEBUG_OPTIONS
 210             )
 211         }
 212     } else {
 213         true
 214     }
 215 }
 216
 217 fn counter_format_option_val(strval: &str) -> ExpressionFormat {
 218     let mut counter_format = ExpressionFormat { id: false, block: false, operation: false };
 219     let components = strval.splitn(3, '+');
 220     for component in components {
 221         match component {
 222             "id" => counter_format.id = true,
 223             "block" => counter_format.block = true,
 224             "operation" => counter_format.operation = true,
 225             _ => bug!(
 226                 "Unsupported counter_format choice `{}` in environment variable {}",
 227                 component,
 228                 RUSTC_COVERAGE_DEBUG_OPTIONS
 229             ),
 230         }
 231     }
 232     counter_format
 233 }
 234
 235 #[derive(Debug, Clone)]
 236 struct ExpressionFormat {
 237     id: bool,
 238     block: bool,
 239     operation: bool,
 240 }
 241
 242 impl Default for ExpressionFormat {
 243     fn default() -> Self {
 244         Self { id: false, block: true, operation: true }
 245     }
 246 }
 247
 248 /// If enabled, this struct maintains a map from `CoverageKind` IDs (as `ExpressionOperandId`) to
 249 /// the `CoverageKind` data and optional label (normally, the counter's associated
 250 /// `BasicCoverageBlock` format string, if any).
 251 ///
 252 /// Use `format_counter` to convert one of these `CoverageKind` counters to a debug output string,
 253 /// as directed by the `DebugOptions`. This allows the format of counter labels in logs and dump
 254 /// files (including the `CoverageGraph` graphviz file) to be changed at runtime, via environment
 255 /// variable.
 256 ///
 257 /// `DebugCounters` supports a recursive rendering of `Expression` counters, so they can be
 258 /// presented as nested expressions such as `(bcb3 - (bcb0 + bcb1))`.
 259 pub(super) struct DebugCounters {
 260     some_counters: Option<FxHashMap<ExpressionOperandId, DebugCounter>>,
 261 }
 262
 263 impl DebugCounters {
 264     pub fn new() -> Self {
 265         Self { some_counters: None }
 266     }
 267
 268     pub fn enable(&mut self) {
 269         debug_assert!(!self.is_enabled());
 270         self.some_counters.replace(FxHashMap::default());
 271     }
 272
 273     pub fn is_enabled(&self) -> bool {
 274         self.some_counters.is_some()
 275     }
 276
 277     pub fn add_counter(&mut self, counter_kind: &CoverageKind, some_block_label: Option<String>) {
 278         if let Some(counters) = &mut self.some_counters {
 279             let id: ExpressionOperandId = match *counter_kind {
 280                 CoverageKind::Counter { id, .. } => id.into(),
 281                 CoverageKind::Expression { id, .. } => id.into(),
 282                 _ => bug!(
 283                     "the given `CoverageKind` is not an counter or expression: {:?}",
 284                     counter_kind
 285                 ),
 286             };
 287             counters
 288                 .try_insert(id, DebugCounter::new(counter_kind.clone(), some_block_label))
 289                 .expect("attempt to add the same counter_kind to DebugCounters more than once");
 290         }
 291     }
 292
 293     pub fn some_block_label(&self, operand: ExpressionOperandId) -> Option<&String> {
 294         self.some_counters.as_ref().map_or(None, |counters| {
 295             counters
 296                 .get(&operand)
 297                 .map_or(None, |debug_counter| debug_counter.some_block_label.as_ref())
 298         })
 299     }
 300
 301     pub fn format_counter(&self, counter_kind: &CoverageKind) -> String {
 302         match *counter_kind {
 303             CoverageKind::Counter { .. } => {
 304                 format!("Counter({})", self.format_counter_kind(counter_kind))
 305             }
 306             CoverageKind::Expression { .. } => {
 307                 format!("Expression({})", self.format_counter_kind(counter_kind))
 308             }
 309             CoverageKind::Unreachable { .. } => "Unreachable".to_owned(),
 310         }
 311     }
 312
 313     fn format_counter_kind(&self, counter_kind: &CoverageKind) -> String {
 314         let counter_format = &debug_options().counter_format;
 315         if let CoverageKind::Expression { id, lhs, op, rhs } = *counter_kind {
 316             if counter_format.operation {
 317                 return format!(
 318                     "{}{} {} {}",
 319                     if counter_format.id || self.some_counters.is_none() {
 320                         format!("#{} = ", id.index())
 321                     } else {
 322                         String::new()
 323                     },
 324                     self.format_operand(lhs),
 325                     if op == Op::Add { "+" } else { "-" },
 326                     self.format_operand(rhs),
 327                 );
 328             }
 329         }
 330
 331         let id: ExpressionOperandId = match *counter_kind {
 332             CoverageKind::Counter { id, .. } => id.into(),
 333             CoverageKind::Expression { id, .. } => id.into(),
 334             _ => {
 335                 bug!("the given `CoverageKind` is not an counter or expression: {:?}", counter_kind)
 336             }
 337         };
 338         if self.some_counters.is_some() && (counter_format.block || !counter_format.id) {
 339             let counters = self.some_counters.as_ref().unwrap();
 340             if let Some(DebugCounter { some_block_label: Some(block_label), .. }) =
 341                 counters.get(&id)
 342             {
 343                 return if counter_format.id {
 344                     format!("{}#{}", block_label, id.index())
 345                 } else {
 346                     block_label.to_string()
 347                 };
 348             }
 349         }
 350         format!("#{}", id.index())
 351     }
 352
 353     fn format_operand(&self, operand: ExpressionOperandId) -> String {
 354         if operand.index() == 0 {
 355             return String::from("0");
 356         }
 357         if let Some(counters) = &self.some_counters {
 358             if let Some(DebugCounter { counter_kind, some_block_label }) = counters.get(&operand) {
 359                 if let CoverageKind::Expression { .. } = counter_kind {
 360                     if let Some(label) = some_block_label && debug_options().counter_format.block {
 361                         return format!(
 362                             "{}:({})",
 363                             label,
 364                             self.format_counter_kind(counter_kind)
 365                         );
 366                     }
 367                     return format!("({})", self.format_counter_kind(counter_kind));
 368                 }
 369                 return self.format_counter_kind(counter_kind);
 370             }
 371         }
 372         format!("#{}", operand.index())
 373     }
 374 }
 375
 376 /// A non-public support class to `DebugCounters`.
 377 #[derive(Debug)]
 378 struct DebugCounter {
 379     counter_kind: CoverageKind,
 380     some_block_label: Option<String>,
 381 }
 382
 383 impl DebugCounter {
 384     fn new(counter_kind: CoverageKind, some_block_label: Option<String>) -> Self {
 385         Self { counter_kind, some_block_label }
 386     }
 387 }
 388
 389 /// If enabled, this data structure captures additional debugging information used when generating
 390 /// a Graphviz (.dot file) representation of the `CoverageGraph`, for debugging purposes.
 391 pub(super) struct GraphvizData {
 392     some_bcb_to_coverage_spans_with_counters:
 393         Option<FxHashMap<BasicCoverageBlock, Vec<(CoverageSpan, CoverageKind)>>>,
 394     some_bcb_to_dependency_counters: Option<FxHashMap<BasicCoverageBlock, Vec<CoverageKind>>>,
 395     some_edge_to_counter: Option<FxHashMap<(BasicCoverageBlock, BasicBlock), CoverageKind>>,
 396 }
 397
 398 impl GraphvizData {
 399     pub fn new() -> Self {
 400         Self {
 401             some_bcb_to_coverage_spans_with_counters: None,
 402             some_bcb_to_dependency_counters: None,
 403             some_edge_to_counter: None,
 404         }
 405     }
 406
 407     pub fn enable(&mut self) {
 408         debug_assert!(!self.is_enabled());
 409         self.some_bcb_to_coverage_spans_with_counters = Some(FxHashMap::default());
 410         self.some_bcb_to_dependency_counters = Some(FxHashMap::default());
 411         self.some_edge_to_counter = Some(FxHashMap::default());
 412     }
 413
 414     pub fn is_enabled(&self) -> bool {
 415         self.some_bcb_to_coverage_spans_with_counters.is_some()
 416     }
 417
 418     pub fn add_bcb_coverage_span_with_counter(
 419         &mut self,
 420         bcb: BasicCoverageBlock,
 421         coverage_span: &CoverageSpan,
 422         counter_kind: &CoverageKind,
 423     ) {
 424         if let Some(bcb_to_coverage_spans_with_counters) =
 425             self.some_bcb_to_coverage_spans_with_counters.as_mut()
 426         {
 427             bcb_to_coverage_spans_with_counters
 428                 .entry(bcb)
 429                 .or_insert_with(Vec::new)
 430                 .push((coverage_span.clone(), counter_kind.clone()));
 431         }
 432     }
 433
 434     pub fn get_bcb_coverage_spans_with_counters(
 435         &self,
 436         bcb: BasicCoverageBlock,
 437     ) -> Option<&Vec<(CoverageSpan, CoverageKind)>> {
 438         if let Some(bcb_to_coverage_spans_with_counters) =
 439             self.some_bcb_to_coverage_spans_with_counters.as_ref()
 440         {
 441             bcb_to_coverage_spans_with_counters.get(&bcb)
 442         } else {
 443             None
 444         }
 445     }
 446
 447     pub fn add_bcb_dependency_counter(
 448         &mut self,
 449         bcb: BasicCoverageBlock,
 450         counter_kind: &CoverageKind,
 451     ) {
 452         if let Some(bcb_to_dependency_counters) = self.some_bcb_to_dependency_counters.as_mut() {
 453             bcb_to_dependency_counters
 454                 .entry(bcb)
 455                 .or_insert_with(Vec::new)
 456                 .push(counter_kind.clone());
 457         }
 458     }
 459
 460     pub fn get_bcb_dependency_counters(
 461         &self,
 462         bcb: BasicCoverageBlock,
 463     ) -> Option<&Vec<CoverageKind>> {
 464         if let Some(bcb_to_dependency_counters) = self.some_bcb_to_dependency_counters.as_ref() {
 465             bcb_to_dependency_counters.get(&bcb)
 466         } else {
 467             None
 468         }
 469     }
 470
 471     pub fn set_edge_counter(
 472         &mut self,
 473         from_bcb: BasicCoverageBlock,
 474         to_bb: BasicBlock,
 475         counter_kind: &CoverageKind,
 476     ) {
 477         if let Some(edge_to_counter) = self.some_edge_to_counter.as_mut() {
 478             edge_to_counter
 479                 .try_insert((from_bcb, to_bb), counter_kind.clone())
 480                 .expect("invalid attempt to insert more than one edge counter for the same edge");
 481         }
 482     }
 483
 484     pub fn get_edge_counter(
 485         &self,
 486         from_bcb: BasicCoverageBlock,
 487         to_bb: BasicBlock,
 488     ) -> Option<&CoverageKind> {
 489         if let Some(edge_to_counter) = self.some_edge_to_counter.as_ref() {
 490             edge_to_counter.get(&(from_bcb, to_bb))
 491         } else {
 492             None
 493         }
 494     }
 495 }
 496
 497 /// If enabled, this struct captures additional data used to track whether expressions were used,
 498 /// directly or indirectly, to compute the coverage counts for all `CoverageSpan`s, and any that are
 499 /// _not_ used are retained in the `unused_expressions` Vec, to be included in debug output (logs
 500 /// and/or a `CoverageGraph` graphviz output).
 501 pub(super) struct UsedExpressions {
 502     some_used_expression_operands:
 503         Option<FxHashMap<ExpressionOperandId, Vec<InjectedExpressionId>>>,
 504     some_unused_expressions:
 505         Option<Vec<(CoverageKind, Option<BasicCoverageBlock>, BasicCoverageBlock)>>,
 506 }
 507
 508 impl UsedExpressions {
 509     pub fn new() -> Self {
 510         Self { some_used_expression_operands: None, some_unused_expressions: None }
 511     }
 512
 513     pub fn enable(&mut self) {
 514         debug_assert!(!self.is_enabled());
 515         self.some_used_expression_operands = Some(FxHashMap::default());
 516         self.some_unused_expressions = Some(Vec::new());
 517     }
 518
 519     pub fn is_enabled(&self) -> bool {
 520         self.some_used_expression_operands.is_some()
 521     }
 522
 523     pub fn add_expression_operands(&mut self, expression: &CoverageKind) {
 524         if let Some(used_expression_operands) = self.some_used_expression_operands.as_mut() {
 525             if let CoverageKind::Expression { id, lhs, rhs, .. } = *expression {
 526                 used_expression_operands.entry(lhs).or_insert_with(Vec::new).push(id);
 527                 used_expression_operands.entry(rhs).or_insert_with(Vec::new).push(id);
 528             }
 529         }
 530     }
 531
 532     pub fn expression_is_used(&self, expression: &CoverageKind) -> bool {
 533         if let Some(used_expression_operands) = self.some_used_expression_operands.as_ref() {
 534             used_expression_operands.contains_key(&expression.as_operand_id())
 535         } else {
 536             false
 537         }
 538     }
 539
 540     pub fn add_unused_expression_if_not_found(
 541         &mut self,
 542         expression: &CoverageKind,
 543         edge_from_bcb: Option<BasicCoverageBlock>,
 544         target_bcb: BasicCoverageBlock,
 545     ) {
 546         if let Some(used_expression_operands) = self.some_used_expression_operands.as_ref() {
 547             if !used_expression_operands.contains_key(&expression.as_operand_id()) {
 548                 self.some_unused_expressions.as_mut().unwrap().push((
 549                     expression.clone(),
 550                     edge_from_bcb,
 551                     target_bcb,
 552                 ));
 553             }
 554         }
 555     }
 556
 557     /// Return the list of unused counters (if any) as a tuple with the counter (`CoverageKind`),
 558     /// optional `from_bcb` (if it was an edge counter), and `target_bcb`.
 559     pub fn get_unused_expressions(
 560         &self,
 561     ) -> Vec<(CoverageKind, Option<BasicCoverageBlock>, BasicCoverageBlock)> {
 562         if let Some(unused_expressions) = self.some_unused_expressions.as_ref() {
 563             unused_expressions.clone()
 564         } else {
 565             Vec::new()
 566         }
 567     }
 568
 569     /// If enabled, validate that every BCB or edge counter not directly associated with a coverage
 570     /// span is at least indirectly associated (it is a dependency of a BCB counter that _is_
 571     /// associated with a coverage span).
 572     pub fn validate(
 573         &mut self,
 574         bcb_counters_without_direct_coverage_spans: &Vec<(
 575             Option<BasicCoverageBlock>,
 576             BasicCoverageBlock,
 577             CoverageKind,
 578         )>,
 579     ) {
 580         if self.is_enabled() {
 581             let mut not_validated = bcb_counters_without_direct_coverage_spans
 582                 .iter()
 583                 .map(|(_, _, counter_kind)| counter_kind)
 584                 .collect::<Vec<_>>();
 585             let mut validating_count = 0;
 586             while not_validated.len() != validating_count {
 587                 let to_validate = not_validated.split_off(0);
 588                 validating_count = to_validate.len();
 589                 for counter_kind in to_validate {
 590                     if self.expression_is_used(counter_kind) {
 591                         self.add_expression_operands(counter_kind);
 592                     } else {
 593                         not_validated.push(counter_kind);
 594                     }
 595                 }
 596             }
 597         }
 598     }
 599
 600     pub fn alert_on_unused_expressions(&self, debug_counters: &DebugCounters) {
 601         if let Some(unused_expressions) = self.some_unused_expressions.as_ref() {
 602             for (counter_kind, edge_from_bcb, target_bcb) in unused_expressions {
 603                 let unused_counter_message = if let Some(from_bcb) = edge_from_bcb.as_ref() {
 604                     format!(
 605                         "non-coverage edge counter found without a dependent expression, in \
 606                         {:?}->{:?}; counter={}",
 607                         from_bcb,
 608                         target_bcb,
 609                         debug_counters.format_counter(&counter_kind),
 610                     )
 611                 } else {
 612                     format!(
 613                         "non-coverage counter found without a dependent expression, in {:?}; \
 614                         counter={}",
 615                         target_bcb,
 616                         debug_counters.format_counter(&counter_kind),
 617                     )
 618                 };
 619
 620                 if debug_options().allow_unused_expressions {
 621                     debug!("WARNING: {}", unused_counter_message);
 622                 } else {
 623                     bug!("{}", unused_counter_message);
 624                 }
 625             }
 626         }
 627     }
 628 }
 629
 630 /// Generates the MIR pass `CoverageSpan`-specific spanview dump file.
 631 pub(super) fn dump_coverage_spanview<'tcx>(
 632     tcx: TyCtxt<'tcx>,
 633     mir_body: &mir::Body<'tcx>,
 634     basic_coverage_blocks: &CoverageGraph,
 635     pass_name: &str,
 636     body_span: Span,
 637     coverage_spans: &Vec<CoverageSpan>,
 638 ) {
 639     let mir_source = mir_body.source;
 640     let def_id = mir_source.def_id();
 641
 642     let span_viewables = span_viewables(tcx, mir_body, basic_coverage_blocks, &coverage_spans);
 643     let mut file = create_dump_file(tcx, "html", None, pass_name, &0, mir_source)
 644         .expect("Unexpected error creating MIR spanview HTML file");
 645     let crate_name = tcx.crate_name(def_id.krate);
 646     let item_name = tcx.def_path(def_id).to_filename_friendly_no_crate();
 647     let title = format!("{}.{} - Coverage Spans", crate_name, item_name);
 648     spanview::write_document(tcx, body_span, span_viewables, &title, &mut file)
 649         .expect("Unexpected IO error dumping coverage spans as HTML");
 650 }
 651
 652 /// Converts the computed `BasicCoverageBlockData`s into `SpanViewable`s.
 653 fn span_viewables<'tcx>(
 654     tcx: TyCtxt<'tcx>,
 655     mir_body: &mir::Body<'tcx>,
 656     basic_coverage_blocks: &CoverageGraph,
 657     coverage_spans: &Vec<CoverageSpan>,
 658 ) -> Vec<SpanViewable> {
 659     let mut span_viewables = Vec::new();
 660     for coverage_span in coverage_spans {
 661         let tooltip = coverage_span.format_coverage_statements(tcx, mir_body);
 662         let CoverageSpan { span, bcb, .. } = coverage_span;
 663         let bcb_data = &basic_coverage_blocks[*bcb];
 664         let id = bcb_data.id();
 665         let leader_bb = bcb_data.leader_bb();
 666         span_viewables.push(SpanViewable { bb: leader_bb, span: *span, id, tooltip });
 667     }
 668     span_viewables
 669 }
 670
 671 /// Generates the MIR pass coverage-specific graphviz dump file.
 672 pub(super) fn dump_coverage_graphviz<'tcx>(
 673     tcx: TyCtxt<'tcx>,
 674     mir_body: &mir::Body<'tcx>,
 675     pass_name: &str,
 676     basic_coverage_blocks: &CoverageGraph,
 677     debug_counters: &DebugCounters,
 678     graphviz_data: &GraphvizData,
 679     intermediate_expressions: &Vec<CoverageKind>,
 680     debug_used_expressions: &UsedExpressions,
 681 ) {
 682     let mir_source = mir_body.source;
 683     let def_id = mir_source.def_id();
 684     let node_content = |bcb| {
 685         bcb_to_string_sections(
 686             tcx,
 687             mir_body,
 688             debug_counters,
 689             &basic_coverage_blocks[bcb],
 690             graphviz_data.get_bcb_coverage_spans_with_counters(bcb),
 691             graphviz_data.get_bcb_dependency_counters(bcb),
 692             // intermediate_expressions are injected into the mir::START_BLOCK, so
 693             // include them in the first BCB.
 694             if bcb.index() == 0 { Some(&intermediate_expressions) } else { None },
 695         )
 696     };
 697     let edge_labels = |from_bcb| {
 698         let from_bcb_data = &basic_coverage_blocks[from_bcb];
 699         let from_terminator = from_bcb_data.terminator(mir_body);
 700         let mut edge_labels = from_terminator.kind.fmt_successor_labels();
 701         edge_labels.retain(|label| label != "unreachable");
 702         let edge_counters = from_terminator
 703             .successors()
 704             .map(|successor_bb| graphviz_data.get_edge_counter(from_bcb, successor_bb));
 705         iter::zip(&edge_labels, edge_counters)
 706             .map(|(label, some_counter)| {
 707                 if let Some(counter) = some_counter {
 708                     format!("{}\n{}", label, debug_counters.format_counter(counter))
 709                 } else {
 710                     label.to_string()
 711                 }
 712             })
 713             .collect::<Vec<_>>()
 714     };
 715     let graphviz_name = format!("Cov_{}_{}", def_id.krate.index(), def_id.index.index());
 716     let mut graphviz_writer =
 717         GraphvizWriter::new(basic_coverage_blocks, &graphviz_name, node_content, edge_labels);
 718     let unused_expressions = debug_used_expressions.get_unused_expressions();
 719     if unused_expressions.len() > 0 {
 720         graphviz_writer.set_graph_label(&format!(
 721             "Unused expressions:\n  {}",
 722             unused_expressions
 723                 .as_slice()
 724                 .iter()
 725                 .map(|(counter_kind, edge_from_bcb, target_bcb)| {
 726                     if let Some(from_bcb) = edge_from_bcb.as_ref() {
 727                         format!(
 728                             "{:?}->{:?}: {}",
 729                             from_bcb,
 730                             target_bcb,
 731                             debug_counters.format_counter(&counter_kind),
 732                         )
 733                     } else {
 734                         format!(
 735                             "{:?}: {}",
 736                             target_bcb,
 737                             debug_counters.format_counter(&counter_kind),
 738                         )
 739                     }
 740                 })
 741                 .join("\n  ")
 742         ));
 743     }
 744     let mut file = create_dump_file(tcx, "dot", None, pass_name, &0, mir_source)
 745         .expect("Unexpected error creating BasicCoverageBlock graphviz DOT file");
 746     graphviz_writer
 747         .write_graphviz(tcx, &mut file)
 748         .expect("Unexpected error writing BasicCoverageBlock graphviz DOT file");
 749 }
 750
 751 fn bcb_to_string_sections<'tcx>(
 752     tcx: TyCtxt<'tcx>,
 753     mir_body: &mir::Body<'tcx>,
 754     debug_counters: &DebugCounters,
 755     bcb_data: &BasicCoverageBlockData,
 756     some_coverage_spans_with_counters: Option<&Vec<(CoverageSpan, CoverageKind)>>,
 757     some_dependency_counters: Option<&Vec<CoverageKind>>,
 758     some_intermediate_expressions: Option<&Vec<CoverageKind>>,
 759 ) -> Vec<String> {
 760     let len = bcb_data.basic_blocks.len();
 761     let mut sections = Vec::new();
 762     if let Some(collect_intermediate_expressions) = some_intermediate_expressions {
 763         sections.push(
 764             collect_intermediate_expressions
 765                 .iter()
 766                 .map(|expression| {
 767                     format!("Intermediate {}", debug_counters.format_counter(expression))
 768                 })
 769                 .join("\n"),
 770         );
 771     }
 772     if let Some(coverage_spans_with_counters) = some_coverage_spans_with_counters {
 773         sections.push(
 774             coverage_spans_with_counters
 775                 .iter()
 776                 .map(|(covspan, counter)| {
 777                     format!(
 778                         "{} at {}",
 779                         debug_counters.format_counter(counter),
 780                         covspan.format(tcx, mir_body)
 781                     )
 782                 })
 783                 .join("\n"),
 784         );
 785     }
 786     if let Some(dependency_counters) = some_dependency_counters {
 787         sections.push(format!(
 788             "Non-coverage counters:\n  {}",
 789             dependency_counters
 790                 .iter()
 791                 .map(|counter| debug_counters.format_counter(counter))
 792                 .join("  \n"),
 793         ));
 794     }
 795     if let Some(counter_kind) = &bcb_data.counter_kind {
 796         sections.push(format!("{:?}", counter_kind));
 797     }
 798     let non_term_blocks = bcb_data.basic_blocks[0..len - 1]
 799         .iter()
 800         .map(|&bb| format!("{:?}: {}", bb, term_type(&mir_body[bb].terminator().kind)))
 801         .collect::<Vec<_>>();
 802     if non_term_blocks.len() > 0 {
 803         sections.push(non_term_blocks.join("\n"));
 804     }
 805     sections.push(format!(
 806         "{:?}: {}",
 807         bcb_data.basic_blocks.last().unwrap(),
 808         term_type(&bcb_data.terminator(mir_body).kind)
 809     ));
 810     sections
 811 }
 812
 813 /// Returns a simple string representation of a `TerminatorKind` variant, independent of any
 814 /// values it might hold.
 815 pub(super) fn term_type(kind: &TerminatorKind<'_>) -> &'static str {
 816     match kind {
 817         TerminatorKind::Goto { .. } => "Goto",
 818         TerminatorKind::SwitchInt { .. } => "SwitchInt",
 819         TerminatorKind::Resume => "Resume",
 820         TerminatorKind::Abort => "Abort",
 821         TerminatorKind::Return => "Return",
 822         TerminatorKind::Unreachable => "Unreachable",
 823         TerminatorKind::Drop { .. } => "Drop",
 824         TerminatorKind::DropAndReplace { .. } => "DropAndReplace",
 825         TerminatorKind::Call { .. } => "Call",
 826         TerminatorKind::Assert { .. } => "Assert",
 827         TerminatorKind::Yield { .. } => "Yield",
 828         TerminatorKind::GeneratorDrop => "GeneratorDrop",
 829         TerminatorKind::FalseEdge { .. } => "FalseEdge",
 830         TerminatorKind::FalseUnwind { .. } => "FalseUnwind",
 831         TerminatorKind::InlineAsm { .. } => "InlineAsm",
 832     }
 833 }