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::mir::mono::CodegenUnitNameBuilder;
  25 use rustc::ty::TyCtxt;
  26 use rustc_hir::def_id::LOCAL_CRATE;
  27 use rustc_session::cgu_reuse_tracker::*;
  28 use rustc_span::symbol::{sym, Symbol};
  29 use std::collections::BTreeSet;
  30 use syntax::ast;
  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())
  43             .collect::<BTreeSet<Symbol>>();
  44
  45         let ams = AssertModuleSource { tcx, available_cgus };
  46
  47         for attr in tcx.hir().krate().attrs {
  48             ams.check_attr(attr);
  49         }
  50     })
  51 }
  52
  53 struct AssertModuleSource<'tcx> {
  54     tcx: TyCtxt<'tcx>,
  55     available_cgus: BTreeSet<Symbol>,
  56 }
  57
  58 impl AssertModuleSource<'tcx> {
  59     fn check_attr(&self, attr: &ast::Attribute) {
  60         let (expected_reuse, comp_kind) = if attr.check_name(sym::rustc_partition_reused) {
  61             (CguReuse::PreLto, ComparisonKind::AtLeast)
  62         } else if attr.check_name(sym::rustc_partition_codegened) {
  63             (CguReuse::No, ComparisonKind::Exact)
  64         } else if attr.check_name(sym::rustc_expected_cgu_reuse) {
  65             match &*self.field(attr, sym::kind).as_str() {
  66                 "no" => (CguReuse::No, ComparisonKind::Exact),
  67                 "pre-lto" => (CguReuse::PreLto, ComparisonKind::Exact),
  68                 "post-lto" => (CguReuse::PostLto, ComparisonKind::Exact),
  69                 "any" => (CguReuse::PreLto, ComparisonKind::AtLeast),
  70                 other => {
  71                     self.tcx.sess.span_fatal(
  72                         attr.span,
  73                         &format!("unknown cgu-reuse-kind `{}` specified", other),
  74                     );
  75                 }
  76             }
  77         } else {
  78             return;
  79         };
  80
  81         if !self.tcx.sess.opts.debugging_opts.query_dep_graph {
  82             self.tcx.sess.span_fatal(
  83                 attr.span,
  84                 &format!(
  85                     "found CGU-reuse attribute but `-Zquery-dep-graph` \
  86                           was not specified"
  87                 ),
  88             );
  89         }
  90
  91         if !self.check_config(attr) {
  92             debug!("check_attr: config does not match, ignoring attr");
  93             return;
  94         }
  95
  96         let user_path = self.field(attr, sym::module).to_string();
  97         let crate_name = self.tcx.crate_name(LOCAL_CRATE).to_string();
  98
  99         if !user_path.starts_with(&crate_name) {
 100             let msg = format!(
 101                 "Found malformed codegen unit name `{}`. \
 102                 Codegen units names must always start with the name of the \
 103                 crate (`{}` in this case).",
 104                 user_path, crate_name
 105             );
 106             self.tcx.sess.span_fatal(attr.span, &msg);
 107         }
 108
 109         // Split of the "special suffix" if there is one.
 110         let (user_path, cgu_special_suffix) = if let Some(index) = user_path.rfind(".") {
 111             (&user_path[..index], Some(&user_path[index + 1..]))
 112         } else {
 113             (&user_path[..], None)
 114         };
 115
 116         let mut cgu_path_components = user_path.split('-').collect::<Vec<_>>();
 117
 118         // Remove the crate name
 119         assert_eq!(cgu_path_components.remove(0), crate_name);
 120
 121         let cgu_name_builder = &mut CodegenUnitNameBuilder::new(self.tcx);
 122         let cgu_name =
 123             cgu_name_builder.build_cgu_name(LOCAL_CRATE, cgu_path_components, cgu_special_suffix);
 124
 125         debug!("mapping '{}' to cgu name '{}'", self.field(attr, sym::module), cgu_name);
 126
 127         if !self.available_cgus.contains(&cgu_name) {
 128             self.tcx.sess.span_err(
 129                 attr.span,
 130                 &format!(
 131                     "no module named `{}` (mangled: {}). \
 132                           Available modules: {}",
 133                     user_path,
 134                     cgu_name,
 135                     self.available_cgus
 136                         .iter()
 137                         .map(|cgu| cgu.to_string())
 138                         .collect::<Vec<_>>()
 139                         .join(", ")
 140                 ),
 141             );
 142         }
 143
 144         self.tcx.sess.cgu_reuse_tracker.set_expectation(
 145             &cgu_name.as_str(),
 146             &user_path,
 147             attr.span,
 148             expected_reuse,
 149             comp_kind,
 150         );
 151     }
 152
 153     fn field(&self, attr: &ast::Attribute, name: Symbol) -> ast::Name {
 154         for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
 155             if item.check_name(name) {
 156                 if let Some(value) = item.value_str() {
 157                     return value;
 158                 } else {
 159                     self.tcx.sess.span_fatal(
 160                         item.span(),
 161                         &format!("associated value expected for `{}`", name),
 162                     );
 163                 }
 164             }
 165         }
 166
 167         self.tcx.sess.span_fatal(attr.span, &format!("no field `{}`", name));
 168     }
 169
 170     /// Scan for a `cfg="foo"` attribute and check whether we have a
 171     /// cfg flag called `foo`.
 172     fn check_config(&self, attr: &ast::Attribute) -> bool {
 173         let config = &self.tcx.sess.parse_sess.config;
 174         let value = self.field(attr, sym::cfg);
 175         debug!("check_config(config={:?}, value={:?})", config, value);
 176         if config.iter().any(|&(name, _)| name == value) {
 177             debug!("check_config: matched");
 178             return true;
 179         }
 180         debug!("check_config: no match found");
 181         return false;
 182     }
 183 }