src/librustc_incremental/assert_module_sources.rs

   1 //! This pass is only used for UNIT TESTS related to incremental
   2 //! compilation. It tests whether a particular `.o` file will be re-used
   3 //! from a previous compilation or whether it must be regenerated.
   4 //!
   5 //! The user adds annotations to the crate of the following form:
   6 //!
   7 //! ```
   8 //! #![rustc_partition_reused(module="spike", cfg="rpass2")]
   9 //! #![rustc_partition_codegened(module="spike-x", cfg="rpass2")]
  10 //! ```
  11 //!
  12 //! The first indicates (in the cfg `rpass2`) that `spike.o` will be
  13 //! reused, the second that `spike-x.o` will be recreated. If these
  14 //! annotations are inaccurate, errors are reported.
  15 //!
  16 //! The reason that we use `cfg=...` and not `#[cfg_attr]` is so that
  17 //! the HIR doesn't change as a result of the annotations, which might
  18 //! perturb the reuse results.
  19 //!
  20 //! `#![rustc_expected_cgu_reuse(module="spike", cfg="rpass2", kind="post-lto")]
  21 //! allows for doing a more fine-grained check to see if pre- or post-lto data
  22 //! was re-used.
  23
  24 use rustc_ast as ast;
  25 use rustc_hir::def_id::LOCAL_CRATE;
  26 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
  27 use rustc_middle::ty::TyCtxt;
  28 use rustc_session::cgu_reuse_tracker::*;
  29 use rustc_span::symbol::{sym, Symbol};
  30 use std::collections::BTreeSet;
  31
  32 pub fn assert_module_sources(tcx: TyCtxt<'_>) {
  33     tcx.dep_graph.with_ignore(|| {
  34         if tcx.sess.opts.incremental.is_none() {
  35             return;
  36         }
  37
  38         let available_cgus = tcx
  39             .collect_and_partition_mono_items(LOCAL_CRATE)
  40             .1
  41             .iter()
  42             .map(|cgu| cgu.name().to_string())
  43             .collect::<BTreeSet<String>>();
  44
  45         let ams = AssertModuleSource { tcx, available_cgus };
  46
  47         for attr in tcx.hir().krate().item.attrs {
  48             ams.check_attr(attr);
  49         }
  50     })
  51 }
  52
  53 struct AssertModuleSource<'tcx> {
  54     tcx: TyCtxt<'tcx>,
  55     available_cgus: BTreeSet<String>,
  56 }
  57
  58 impl AssertModuleSource<'tcx> {
  59     fn check_attr(&self, attr: &ast::Attribute) {
  60         let (expected_reuse, comp_kind) =
  61             if self.tcx.sess.check_name(attr, sym::rustc_partition_reused) {
  62                 (CguReuse::PreLto, ComparisonKind::AtLeast)
  63             } else if self.tcx.sess.check_name(attr, sym::rustc_partition_codegened) {
  64                 (CguReuse::No, ComparisonKind::Exact)
  65             } else if self.tcx.sess.check_name(attr, sym::rustc_expected_cgu_reuse) {
  66                 match self.field(attr, sym::kind) {
  67                     sym::no => (CguReuse::No, ComparisonKind::Exact),
  68                     sym::pre_dash_lto => (CguReuse::PreLto, ComparisonKind::Exact),
  69                     sym::post_dash_lto => (CguReuse::PostLto, ComparisonKind::Exact),
  70                     sym::any => (CguReuse::PreLto, ComparisonKind::AtLeast),
  71                     other => {
  72                         self.tcx.sess.span_fatal(
  73                             attr.span,
  74                             &format!("unknown cgu-reuse-kind `{}` specified", other),
  75                         );
  76                     }
  77                 }
  78             } else {
  79                 return;
  80             };
  81
  82         if !self.tcx.sess.opts.debugging_opts.query_dep_graph {
  83             self.tcx.sess.span_fatal(
  84                 attr.span,
  85                 "found CGU-reuse attribute but `-Zquery-dep-graph` was not specified",
  86             );
  87         }
  88
  89         if !self.check_config(attr) {
  90             debug!("check_attr: config does not match, ignoring attr");
  91             return;
  92         }
  93
  94         let user_path = self.field(attr, sym::module).to_string();
  95         let crate_name = self.tcx.crate_name(LOCAL_CRATE).to_string();
  96
  97         if !user_path.starts_with(&crate_name) {
  98             let msg = format!(
  99                 "Found malformed codegen unit name `{}`. \
 100                 Codegen units names must always start with the name of the \
 101                 crate (`{}` in this case).",
 102                 user_path, crate_name
 103             );
 104             self.tcx.sess.span_fatal(attr.span, &msg);
 105         }
 106
 107         // Split of the "special suffix" if there is one.
 108         let (user_path, cgu_special_suffix) = if let Some(index) = user_path.rfind('.') {
 109             (&user_path[..index], Some(&user_path[index + 1..]))
 110         } else {
 111             (&user_path[..], None)
 112         };
 113
 114         let mut cgu_path_components = user_path.split('-').collect::<Vec<_>>();
 115
 116         // Remove the crate name
 117         assert_eq!(cgu_path_components.remove(0), crate_name);
 118
 119         let cgu_name_builder = &mut CodegenUnitNameBuilder::new(self.tcx);
 120         let cgu_name =
 121             cgu_name_builder.build_cgu_name(LOCAL_CRATE, cgu_path_components, cgu_special_suffix);
 122
 123         debug!("mapping '{}' to cgu name '{}'", self.field(attr, sym::module), cgu_name);
 124
 125         if !self.available_cgus.contains(&*cgu_name.as_str()) {
 126             self.tcx.sess.span_err(
 127                 attr.span,
 128                 &format!(
 129                     "no module named `{}` (mangled: {}). Available modules: {}",
 130                     user_path,
 131                     cgu_name,
 132                     self.available_cgus
 133                         .iter()
 134                         .map(|cgu| cgu.to_string())
 135                         .collect::<Vec<_>>()
 136                         .join(", ")
 137                 ),
 138             );
 139         }
 140
 141         self.tcx.sess.cgu_reuse_tracker.set_expectation(
 142             cgu_name,
 143             &user_path,
 144             attr.span,
 145             expected_reuse,
 146             comp_kind,
 147         );
 148     }
 149
 150     fn field(&self, attr: &ast::Attribute, name: Symbol) -> Symbol {
 151         for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
 152             if item.has_name(name) {
 153                 if let Some(value) = item.value_str() {
 154                     return value;
 155                 } else {
 156                     self.tcx.sess.span_fatal(
 157                         item.span(),
 158                         &format!("associated value expected for `{}`", name),
 159                     );
 160                 }
 161             }
 162         }
 163
 164         self.tcx.sess.span_fatal(attr.span, &format!("no field `{}`", name));
 165     }
 166
 167     /// Scan for a `cfg="foo"` attribute and check whether we have a
 168     /// cfg flag called `foo`.
 169     fn check_config(&self, attr: &ast::Attribute) -> bool {
 170         let config = &self.tcx.sess.parse_sess.config;
 171         let value = self.field(attr, sym::cfg);
 172         debug!("check_config(config={:?}, value={:?})", config, value);
 173         if config.iter().any(|&(name, _)| name == value) {
 174             debug!("check_config: matched");
 175             return true;
 176         }
 177         debug!("check_config: no match found");
 178         false
 179     }
 180 }