| //! Finds crate binaries and loads their metadata |
| //! |
| //! Might I be the first to welcome you to a world of platform differences, |
| //! version requirements, dependency graphs, conflicting desires, and fun! This |
| //! is the major guts (along with metadata::creader) of the compiler for loading |
| //! crates and resolving dependencies. Let's take a tour! |
| //! |
| //! # The problem |
| //! |
| //! Each invocation of the compiler is immediately concerned with one primary |
| //! problem, to connect a set of crates to resolved crates on the filesystem. |
| //! Concretely speaking, the compiler follows roughly these steps to get here: |
| //! |
| //! 1. Discover a set of `extern crate` statements. |
| //! 2. Transform these directives into crate names. If the directive does not |
| //! have an explicit name, then the identifier is the name. |
| //! 3. For each of these crate names, find a corresponding crate on the |
| //! filesystem. |
| //! |
| //! Sounds easy, right? Let's walk into some of the nuances. |
| //! |
| //! ## Transitive Dependencies |
| //! |
| //! Let's say we've got three crates: A, B, and C. A depends on B, and B depends |
| //! on C. When we're compiling A, we primarily need to find and locate B, but we |
| //! also end up needing to find and locate C as well. |
| //! |
| //! The reason for this is that any of B's types could be composed of C's types, |
| //! any function in B could return a type from C, etc. To be able to guarantee |
| //! that we can always type-check/translate any function, we have to have |
| //! complete knowledge of the whole ecosystem, not just our immediate |
| //! dependencies. |
| //! |
| //! So now as part of the "find a corresponding crate on the filesystem" step |
| //! above, this involves also finding all crates for *all upstream |
| //! dependencies*. This includes all dependencies transitively. |
| //! |
| //! ## Rlibs and Dylibs |
| //! |
| //! The compiler has two forms of intermediate dependencies. These are dubbed |
| //! rlibs and dylibs for the static and dynamic variants, respectively. An rlib |
| //! is a rustc-defined file format (currently just an ar archive) while a dylib |
| //! is a platform-defined dynamic library. Each library has a metadata somewhere |
| //! inside of it. |
| //! |
| //! A third kind of dependency is an rmeta file. These are metadata files and do |
| //! not contain any code, etc. To a first approximation, these are treated in the |
| //! same way as rlibs. Where there is both an rlib and an rmeta file, the rlib |
| //! gets priority (even if the rmeta file is newer). An rmeta file is only |
| //! useful for checking a downstream crate, attempting to link one will cause an |
| //! error. |
| //! |
| //! When translating a crate name to a crate on the filesystem, we all of a |
| //! sudden need to take into account both rlibs and dylibs! Linkage later on may |
| //! use either one of these files, as each has their pros/cons. The job of crate |
| //! loading is to discover what's possible by finding all candidates. |
| //! |
| //! Most parts of this loading systems keep the dylib/rlib as just separate |
| //! variables. |
| //! |
| //! ## Where to look? |
| //! |
| //! We can't exactly scan your whole hard drive when looking for dependencies, |
| //! so we need to places to look. Currently the compiler will implicitly add the |
| //! target lib search path ($prefix/lib/rustlib/$target/lib) to any compilation, |
| //! and otherwise all -L flags are added to the search paths. |
| //! |
| //! ## What criterion to select on? |
| //! |
| //! This is a pretty tricky area of loading crates. Given a file, how do we know |
| //! whether it's the right crate? Currently, the rules look along these lines: |
| //! |
| //! 1. Does the filename match an rlib/dylib pattern? That is to say, does the |
| //! filename have the right prefix/suffix? |
| //! 2. Does the filename have the right prefix for the crate name being queried? |
| //! This is filtering for files like `libfoo*.rlib` and such. If the crate |
| //! we're looking for was originally compiled with -C extra-filename, the |
| //! extra filename will be included in this prefix to reduce reading |
| //! metadata from crates that would otherwise share our prefix. |
| //! 3. Is the file an actual rust library? This is done by loading the metadata |
| //! from the library and making sure it's actually there. |
| //! 4. Does the name in the metadata agree with the name of the library? |
| //! 5. Does the target in the metadata agree with the current target? |
| //! 6. Does the SVH match? (more on this later) |
| //! |
| //! If the file answers `yes` to all these questions, then the file is |
| //! considered as being *candidate* for being accepted. It is illegal to have |
| //! more than two candidates as the compiler has no method by which to resolve |
| //! this conflict. Additionally, rlib/dylib candidates are considered |
| //! separately. |
| //! |
| //! After all this has happened, we have 1 or two files as candidates. These |
| //! represent the rlib/dylib file found for a library, and they're returned as |
| //! being found. |
| //! |
| //! ### What about versions? |
| //! |
| //! A lot of effort has been put forth to remove versioning from the compiler. |
| //! There have been forays in the past to have versioning baked in, but it was |
| //! largely always deemed insufficient to the point that it was recognized that |
| //! it's probably something the compiler shouldn't do anyway due to its |
| //! complicated nature and the state of the half-baked solutions. |
| //! |
| //! With a departure from versioning, the primary criterion for loading crates |
| //! is just the name of a crate. If we stopped here, it would imply that you |
| //! could never link two crates of the same name from different sources |
| //! together, which is clearly a bad state to be in. |
| //! |
| //! To resolve this problem, we come to the next section! |
| //! |
| //! # Expert Mode |
| //! |
| //! A number of flags have been added to the compiler to solve the "version |
| //! problem" in the previous section, as well as generally enabling more |
| //! powerful usage of the crate loading system of the compiler. The goal of |
| //! these flags and options are to enable third-party tools to drive the |
| //! compiler with prior knowledge about how the world should look. |
| //! |
| //! ## The `--extern` flag |
| //! |
| //! The compiler accepts a flag of this form a number of times: |
| //! |
| //! ```text |
| //! --extern crate-name=path/to/the/crate.rlib |
| //! ``` |
| //! |
| //! This flag is basically the following letter to the compiler: |
| //! |
| //! > Dear rustc, |
| //! > |
| //! > When you are attempting to load the immediate dependency `crate-name`, I |
| //! > would like you to assume that the library is located at |
| //! > `path/to/the/crate.rlib`, and look nowhere else. Also, please do not |
| //! > assume that the path I specified has the name `crate-name`. |
| //! |
| //! This flag basically overrides most matching logic except for validating that |
| //! the file is indeed a rust library. The same `crate-name` can be specified |
| //! twice to specify the rlib/dylib pair. |
| //! |
| //! ## Enabling "multiple versions" |
| //! |
| //! This basically boils down to the ability to specify arbitrary packages to |
| //! the compiler. For example, if crate A wanted to use Bv1 and Bv2, then it |
| //! would look something like: |
| //! |
| //! ```compile_fail,E0463 |
| //! extern crate b1; |
| //! extern crate b2; |
| //! |
| //! fn main() {} |
| //! ``` |
| //! |
| //! and the compiler would be invoked as: |
| //! |
| //! ```text |
| //! rustc a.rs --extern b1=path/to/libb1.rlib --extern b2=path/to/libb2.rlib |
| //! ``` |
| //! |
| //! In this scenario there are two crates named `b` and the compiler must be |
| //! manually driven to be informed where each crate is. |
| //! |
| //! ## Frobbing symbols |
| //! |
| //! One of the immediate problems with linking the same library together twice |
| //! in the same problem is dealing with duplicate symbols. The primary way to |
| //! deal with this in rustc is to add hashes to the end of each symbol. |
| //! |
| //! In order to force hashes to change between versions of a library, if |
| //! desired, the compiler exposes an option `-C metadata=foo`, which is used to |
| //! initially seed each symbol hash. The string `foo` is prepended to each |
| //! string-to-hash to ensure that symbols change over time. |
| //! |
| //! ## Loading transitive dependencies |
| //! |
| //! Dealing with same-named-but-distinct crates is not just a local problem, but |
| //! one that also needs to be dealt with for transitive dependencies. Note that |
| //! in the letter above `--extern` flags only apply to the *local* set of |
| //! dependencies, not the upstream transitive dependencies. Consider this |
| //! dependency graph: |
| //! |
| //! ```text |
| //! A.1 A.2 |
| //! | | |
| //! | | |
| //! B C |
| //! \ / |
| //! \ / |
| //! D |
| //! ``` |
| //! |
| //! In this scenario, when we compile `D`, we need to be able to distinctly |
| //! resolve `A.1` and `A.2`, but an `--extern` flag cannot apply to these |
| //! transitive dependencies. |
| //! |
| //! Note that the key idea here is that `B` and `C` are both *already compiled*. |
| //! That is, they have already resolved their dependencies. Due to unrelated |
| //! technical reasons, when a library is compiled, it is only compatible with |
| //! the *exact same* version of the upstream libraries it was compiled against. |
| //! We use the "Strict Version Hash" to identify the exact copy of an upstream |
| //! library. |
| //! |
| //! With this knowledge, we know that `B` and `C` will depend on `A` with |
| //! different SVH values, so we crawl the normal `-L` paths looking for |
| //! `liba*.rlib` and filter based on the contained SVH. |
| //! |
| //! In the end, this ends up not needing `--extern` to specify upstream |
| //! transitive dependencies. |
| //! |
| //! # Wrapping up |
| //! |
| //! That's the general overview of loading crates in the compiler, but it's by |
| //! no means all of the necessary details. Take a look at the rest of |
| //! metadata::locator or metadata::creader for all the juicy details! |
| |
| use crate::creader::Library; |
| use crate::errors; |
| use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER}; |
| |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_data_structures::memmap::Mmap; |
| use rustc_data_structures::owned_slice::slice_owned; |
| use rustc_data_structures::svh::Svh; |
| use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg}; |
| use rustc_fs_util::try_canonicalize; |
| use rustc_session::config; |
| use rustc_session::cstore::{CrateSource, MetadataLoader}; |
| use rustc_session::filesearch::FileSearch; |
| use rustc_session::search_paths::PathKind; |
| use rustc_session::utils::CanonicalizedPath; |
| use rustc_session::Session; |
| use rustc_span::symbol::Symbol; |
| use rustc_span::Span; |
| use rustc_target::spec::{Target, TargetTriple}; |
| |
| use snap::read::FrameDecoder; |
| use std::borrow::Cow; |
| use std::io::{Read, Result as IoResult, Write}; |
| use std::ops::Deref; |
| use std::path::{Path, PathBuf}; |
| use std::{cmp, fmt}; |
| |
| #[derive(Clone)] |
| pub(crate) struct CrateLocator<'a> { |
| // Immutable per-session configuration. |
| only_needs_metadata: bool, |
| sysroot: &'a Path, |
| metadata_loader: &'a dyn MetadataLoader, |
| cfg_version: &'static str, |
| |
| // Immutable per-search configuration. |
| crate_name: Symbol, |
| exact_paths: Vec<CanonicalizedPath>, |
| pub hash: Option<Svh>, |
| extra_filename: Option<&'a str>, |
| pub target: &'a Target, |
| pub triple: TargetTriple, |
| pub filesearch: FileSearch<'a>, |
| pub is_proc_macro: bool, |
| |
| // Mutable in-progress state or output. |
| crate_rejections: CrateRejections, |
| } |
| |
| #[derive(Clone)] |
| pub(crate) struct CratePaths { |
| name: Symbol, |
| source: CrateSource, |
| } |
| |
| impl CratePaths { |
| pub(crate) fn new(name: Symbol, source: CrateSource) -> CratePaths { |
| CratePaths { name, source } |
| } |
| } |
| |
| #[derive(Copy, Clone, PartialEq)] |
| pub(crate) enum CrateFlavor { |
| Rlib, |
| Rmeta, |
| Dylib, |
| } |
| |
| impl fmt::Display for CrateFlavor { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.write_str(match *self { |
| CrateFlavor::Rlib => "rlib", |
| CrateFlavor::Rmeta => "rmeta", |
| CrateFlavor::Dylib => "dylib", |
| }) |
| } |
| } |
| |
| impl IntoDiagnosticArg for CrateFlavor { |
| fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> { |
| match self { |
| CrateFlavor::Rlib => DiagnosticArgValue::Str(Cow::Borrowed("rlib")), |
| CrateFlavor::Rmeta => DiagnosticArgValue::Str(Cow::Borrowed("rmeta")), |
| CrateFlavor::Dylib => DiagnosticArgValue::Str(Cow::Borrowed("dylib")), |
| } |
| } |
| } |
| |
| impl<'a> CrateLocator<'a> { |
| pub(crate) fn new( |
| sess: &'a Session, |
| metadata_loader: &'a dyn MetadataLoader, |
| crate_name: Symbol, |
| is_rlib: bool, |
| hash: Option<Svh>, |
| extra_filename: Option<&'a str>, |
| is_host: bool, |
| path_kind: PathKind, |
| ) -> CrateLocator<'a> { |
| let needs_object_code = sess.opts.output_types.should_codegen(); |
| // If we're producing an rlib, then we don't need object code. |
| // Or, if we're not producing object code, then we don't need it either |
| // (e.g., if we're a cdylib but emitting just metadata). |
| let only_needs_metadata = is_rlib || !needs_object_code; |
| |
| CrateLocator { |
| only_needs_metadata, |
| sysroot: &sess.sysroot, |
| metadata_loader, |
| cfg_version: sess.cfg_version, |
| crate_name, |
| exact_paths: if hash.is_none() { |
| sess.opts |
| .externs |
| .get(crate_name.as_str()) |
| .into_iter() |
| .filter_map(|entry| entry.files()) |
| .flatten() |
| .cloned() |
| .collect() |
| } else { |
| // SVH being specified means this is a transitive dependency, |
| // so `--extern` options do not apply. |
| Vec::new() |
| }, |
| hash, |
| extra_filename, |
| target: if is_host { &sess.host } else { &sess.target }, |
| triple: if is_host { |
| TargetTriple::from_triple(config::host_triple()) |
| } else { |
| sess.opts.target_triple.clone() |
| }, |
| filesearch: if is_host { |
| sess.host_filesearch(path_kind) |
| } else { |
| sess.target_filesearch(path_kind) |
| }, |
| is_proc_macro: false, |
| crate_rejections: CrateRejections::default(), |
| } |
| } |
| |
| pub(crate) fn reset(&mut self) { |
| self.crate_rejections.via_hash.clear(); |
| self.crate_rejections.via_triple.clear(); |
| self.crate_rejections.via_kind.clear(); |
| self.crate_rejections.via_version.clear(); |
| self.crate_rejections.via_filename.clear(); |
| self.crate_rejections.via_invalid.clear(); |
| } |
| |
| pub(crate) fn maybe_load_library_crate(&mut self) -> Result<Option<Library>, CrateError> { |
| if !self.exact_paths.is_empty() { |
| return self.find_commandline_library(); |
| } |
| let mut seen_paths = FxHashSet::default(); |
| if let Some(extra_filename) = self.extra_filename { |
| if let library @ Some(_) = self.find_library_crate(extra_filename, &mut seen_paths)? { |
| return Ok(library); |
| } |
| } |
| self.find_library_crate("", &mut seen_paths) |
| } |
| |
| fn find_library_crate( |
| &mut self, |
| extra_prefix: &str, |
| seen_paths: &mut FxHashSet<PathBuf>, |
| ) -> Result<Option<Library>, CrateError> { |
| let rmeta_prefix = &format!("lib{}{}", self.crate_name, extra_prefix); |
| let rlib_prefix = rmeta_prefix; |
| let dylib_prefix = |
| &format!("{}{}{}", self.target.dll_prefix, self.crate_name, extra_prefix); |
| let staticlib_prefix = |
| &format!("{}{}{}", self.target.staticlib_prefix, self.crate_name, extra_prefix); |
| |
| let rmeta_suffix = ".rmeta"; |
| let rlib_suffix = ".rlib"; |
| let dylib_suffix = &self.target.dll_suffix; |
| let staticlib_suffix = &self.target.staticlib_suffix; |
| |
| let mut candidates: FxHashMap<_, (FxHashMap<_, _>, FxHashMap<_, _>, FxHashMap<_, _>)> = |
| Default::default(); |
| |
| // First, find all possible candidate rlibs and dylibs purely based on |
| // the name of the files themselves. We're trying to match against an |
| // exact crate name and a possibly an exact hash. |
| // |
| // During this step, we can filter all found libraries based on the |
| // name and id found in the crate id (we ignore the path portion for |
| // filename matching), as well as the exact hash (if specified). If we |
| // end up having many candidates, we must look at the metadata to |
| // perform exact matches against hashes/crate ids. Note that opening up |
| // the metadata is where we do an exact match against the full contents |
| // of the crate id (path/name/id). |
| // |
| // The goal of this step is to look at as little metadata as possible. |
| // Unfortunately, the prefix-based matching sometimes is over-eager. |
| // E.g. if `rlib_suffix` is `libstd` it'll match the file |
| // `libstd_detect-8d6701fb958915ad.rlib` (incorrect) as well as |
| // `libstd-f3ab5b1dea981f17.rlib` (correct). But this is hard to avoid |
| // given that `extra_filename` comes from the `-C extra-filename` |
| // option and thus can be anything, and the incorrect match will be |
| // handled safely in `extract_one`. |
| for search_path in self.filesearch.search_paths() { |
| debug!("searching {}", search_path.dir.display()); |
| for spf in search_path.files.iter() { |
| debug!("testing {}", spf.path.display()); |
| |
| let f = &spf.file_name_str; |
| let (hash, kind) = if f.starts_with(rlib_prefix) && f.ends_with(rlib_suffix) { |
| (&f[rlib_prefix.len()..(f.len() - rlib_suffix.len())], CrateFlavor::Rlib) |
| } else if f.starts_with(rmeta_prefix) && f.ends_with(rmeta_suffix) { |
| (&f[rmeta_prefix.len()..(f.len() - rmeta_suffix.len())], CrateFlavor::Rmeta) |
| } else if f.starts_with(dylib_prefix) && f.ends_with(dylib_suffix.as_ref()) { |
| (&f[dylib_prefix.len()..(f.len() - dylib_suffix.len())], CrateFlavor::Dylib) |
| } else { |
| if f.starts_with(staticlib_prefix) && f.ends_with(staticlib_suffix.as_ref()) { |
| self.crate_rejections.via_kind.push(CrateMismatch { |
| path: spf.path.clone(), |
| got: "static".to_string(), |
| }); |
| } |
| continue; |
| }; |
| |
| info!("lib candidate: {}", spf.path.display()); |
| |
| let (rlibs, rmetas, dylibs) = candidates.entry(hash.to_string()).or_default(); |
| let path = try_canonicalize(&spf.path).unwrap_or_else(|_| spf.path.clone()); |
| if seen_paths.contains(&path) { |
| continue; |
| }; |
| seen_paths.insert(path.clone()); |
| match kind { |
| CrateFlavor::Rlib => rlibs.insert(path, search_path.kind), |
| CrateFlavor::Rmeta => rmetas.insert(path, search_path.kind), |
| CrateFlavor::Dylib => dylibs.insert(path, search_path.kind), |
| }; |
| } |
| } |
| |
| // We have now collected all known libraries into a set of candidates |
| // keyed of the filename hash listed. For each filename, we also have a |
| // list of rlibs/dylibs that apply. Here, we map each of these lists |
| // (per hash), to a Library candidate for returning. |
| // |
| // A Library candidate is created if the metadata for the set of |
| // libraries corresponds to the crate id and hash criteria that this |
| // search is being performed for. |
| let mut libraries = FxHashMap::default(); |
| for (_hash, (rlibs, rmetas, dylibs)) in candidates { |
| if let Some((svh, lib)) = self.extract_lib(rlibs, rmetas, dylibs)? { |
| libraries.insert(svh, lib); |
| } |
| } |
| |
| // Having now translated all relevant found hashes into libraries, see |
| // what we've got and figure out if we found multiple candidates for |
| // libraries or not. |
| match libraries.len() { |
| 0 => Ok(None), |
| 1 => Ok(Some(libraries.into_iter().next().unwrap().1)), |
| _ => { |
| let mut libraries: Vec<_> = libraries.into_values().collect(); |
| |
| libraries.sort_by_cached_key(|lib| lib.source.paths().next().unwrap().clone()); |
| let candidates = libraries |
| .iter() |
| .map(|lib| lib.source.paths().next().unwrap().clone()) |
| .collect::<Vec<_>>(); |
| |
| Err(CrateError::MultipleCandidates( |
| self.crate_name, |
| // these are the same for all candidates |
| get_flavor_from_path(candidates.first().unwrap()), |
| candidates, |
| )) |
| } |
| } |
| } |
| |
| fn extract_lib( |
| &mut self, |
| rlibs: FxHashMap<PathBuf, PathKind>, |
| rmetas: FxHashMap<PathBuf, PathKind>, |
| dylibs: FxHashMap<PathBuf, PathKind>, |
| ) -> Result<Option<(Svh, Library)>, CrateError> { |
| let mut slot = None; |
| // Order here matters, rmeta should come first. See comment in |
| // `extract_one` below. |
| let source = CrateSource { |
| rmeta: self.extract_one(rmetas, CrateFlavor::Rmeta, &mut slot)?, |
| rlib: self.extract_one(rlibs, CrateFlavor::Rlib, &mut slot)?, |
| dylib: self.extract_one(dylibs, CrateFlavor::Dylib, &mut slot)?, |
| }; |
| Ok(slot.map(|(svh, metadata, _)| (svh, Library { source, metadata }))) |
| } |
| |
| fn needs_crate_flavor(&self, flavor: CrateFlavor) -> bool { |
| if flavor == CrateFlavor::Dylib && self.is_proc_macro { |
| return true; |
| } |
| |
| if self.only_needs_metadata { |
| flavor == CrateFlavor::Rmeta |
| } else { |
| // we need all flavors (perhaps not true, but what we do for now) |
| true |
| } |
| } |
| |
| // Attempts to extract *one* library from the set `m`. If the set has no |
| // elements, `None` is returned. If the set has more than one element, then |
| // the errors and notes are emitted about the set of libraries. |
| // |
| // With only one library in the set, this function will extract it, and then |
| // read the metadata from it if `*slot` is `None`. If the metadata couldn't |
| // be read, it is assumed that the file isn't a valid rust library (no |
| // errors are emitted). |
| // |
| // The `PathBuf` in `slot` will only be used for diagnostic purposes. |
| fn extract_one( |
| &mut self, |
| m: FxHashMap<PathBuf, PathKind>, |
| flavor: CrateFlavor, |
| slot: &mut Option<(Svh, MetadataBlob, PathBuf)>, |
| ) -> Result<Option<(PathBuf, PathKind)>, CrateError> { |
| // If we are producing an rlib, and we've already loaded metadata, then |
| // we should not attempt to discover further crate sources (unless we're |
| // locating a proc macro; exact logic is in needs_crate_flavor). This means |
| // that under -Zbinary-dep-depinfo we will not emit a dependency edge on |
| // the *unused* rlib, and by returning `None` here immediately we |
| // guarantee that we do indeed not use it. |
| // |
| // See also #68149 which provides more detail on why emitting the |
| // dependency on the rlib is a bad thing. |
| if slot.is_some() { |
| if m.is_empty() || !self.needs_crate_flavor(flavor) { |
| return Ok(None); |
| } |
| } |
| |
| let mut ret: Option<(PathBuf, PathKind)> = None; |
| let mut err_data: Option<Vec<PathBuf>> = None; |
| for (lib, kind) in m { |
| info!("{} reading metadata from: {}", flavor, lib.display()); |
| if flavor == CrateFlavor::Rmeta && lib.metadata().is_ok_and(|m| m.len() == 0) { |
| // Empty files will cause get_metadata_section to fail. Rmeta |
| // files can be empty, for example with binaries (which can |
| // often appear with `cargo check` when checking a library as |
| // a unittest). We don't want to emit a user-visible warning |
| // in this case as it is not a real problem. |
| debug!("skipping empty file"); |
| continue; |
| } |
| let (hash, metadata) = |
| match get_metadata_section(self.target, flavor, &lib, self.metadata_loader) { |
| Ok(blob) => { |
| if let Some(h) = self.crate_matches(&blob, &lib) { |
| (h, blob) |
| } else { |
| info!("metadata mismatch"); |
| continue; |
| } |
| } |
| Err(MetadataError::LoadFailure(err)) => { |
| info!("no metadata found: {}", err); |
| // The file was present and created by the same compiler version, but we |
| // couldn't load it for some reason. Give a hard error instead of silently |
| // ignoring it, but only if we would have given an error anyway. |
| self.crate_rejections |
| .via_invalid |
| .push(CrateMismatch { path: lib, got: err }); |
| continue; |
| } |
| Err(err @ MetadataError::NotPresent(_)) => { |
| info!("no metadata found: {}", err); |
| continue; |
| } |
| }; |
| // If we see multiple hashes, emit an error about duplicate candidates. |
| if slot.as_ref().is_some_and(|s| s.0 != hash) { |
| if let Some(candidates) = err_data { |
| return Err(CrateError::MultipleCandidates( |
| self.crate_name, |
| flavor, |
| candidates, |
| )); |
| } |
| err_data = Some(vec![slot.take().unwrap().2]); |
| } |
| if let Some(candidates) = &mut err_data { |
| candidates.push(lib); |
| continue; |
| } |
| |
| // Ok so at this point we've determined that `(lib, kind)` above is |
| // a candidate crate to load, and that `slot` is either none (this |
| // is the first crate of its kind) or if some the previous path has |
| // the exact same hash (e.g., it's the exact same crate). |
| // |
| // In principle these two candidate crates are exactly the same so |
| // we can choose either of them to link. As a stupidly gross hack, |
| // however, we favor crate in the sysroot. |
| // |
| // You can find more info in rust-lang/rust#39518 and various linked |
| // issues, but the general gist is that during testing libstd the |
| // compilers has two candidates to choose from: one in the sysroot |
| // and one in the deps folder. These two crates are the exact same |
| // crate but if the compiler chooses the one in the deps folder |
| // it'll cause spurious errors on Windows. |
| // |
| // As a result, we favor the sysroot crate here. Note that the |
| // candidates are all canonicalized, so we canonicalize the sysroot |
| // as well. |
| if let Some((prev, _)) = &ret { |
| let sysroot = self.sysroot; |
| let sysroot = try_canonicalize(sysroot).unwrap_or_else(|_| sysroot.to_path_buf()); |
| if prev.starts_with(&sysroot) { |
| continue; |
| } |
| } |
| *slot = Some((hash, metadata, lib.clone())); |
| ret = Some((lib, kind)); |
| } |
| |
| if let Some(candidates) = err_data { |
| Err(CrateError::MultipleCandidates(self.crate_name, flavor, candidates)) |
| } else { |
| Ok(ret) |
| } |
| } |
| |
| fn crate_matches(&mut self, metadata: &MetadataBlob, libpath: &Path) -> Option<Svh> { |
| let rustc_version = rustc_version(self.cfg_version); |
| let found_version = metadata.get_rustc_version(); |
| if found_version != rustc_version { |
| info!("Rejecting via version: expected {} got {}", rustc_version, found_version); |
| self.crate_rejections |
| .via_version |
| .push(CrateMismatch { path: libpath.to_path_buf(), got: found_version }); |
| return None; |
| } |
| |
| let header = metadata.get_header(); |
| if header.is_proc_macro_crate != self.is_proc_macro { |
| info!( |
| "Rejecting via proc macro: expected {} got {}", |
| self.is_proc_macro, header.is_proc_macro_crate, |
| ); |
| return None; |
| } |
| |
| if self.exact_paths.is_empty() && self.crate_name != header.name { |
| info!("Rejecting via crate name"); |
| return None; |
| } |
| |
| if header.triple != self.triple { |
| info!("Rejecting via crate triple: expected {} got {}", self.triple, header.triple); |
| self.crate_rejections.via_triple.push(CrateMismatch { |
| path: libpath.to_path_buf(), |
| got: header.triple.to_string(), |
| }); |
| return None; |
| } |
| |
| let hash = header.hash; |
| if let Some(expected_hash) = self.hash { |
| if hash != expected_hash { |
| info!("Rejecting via hash: expected {} got {}", expected_hash, hash); |
| self.crate_rejections |
| .via_hash |
| .push(CrateMismatch { path: libpath.to_path_buf(), got: hash.to_string() }); |
| return None; |
| } |
| } |
| |
| Some(hash) |
| } |
| |
| fn find_commandline_library(&mut self) -> Result<Option<Library>, CrateError> { |
| // First, filter out all libraries that look suspicious. We only accept |
| // files which actually exist that have the correct naming scheme for |
| // rlibs/dylibs. |
| let mut rlibs = FxHashMap::default(); |
| let mut rmetas = FxHashMap::default(); |
| let mut dylibs = FxHashMap::default(); |
| for loc in &self.exact_paths { |
| if !loc.canonicalized().exists() { |
| return Err(CrateError::ExternLocationNotExist( |
| self.crate_name, |
| loc.original().clone(), |
| )); |
| } |
| if !loc.original().is_file() { |
| return Err(CrateError::ExternLocationNotFile( |
| self.crate_name, |
| loc.original().clone(), |
| )); |
| } |
| let Some(file) = loc.original().file_name().and_then(|s| s.to_str()) else { |
| return Err(CrateError::ExternLocationNotFile( |
| self.crate_name, |
| loc.original().clone(), |
| )); |
| }; |
| |
| if file.starts_with("lib") && (file.ends_with(".rlib") || file.ends_with(".rmeta")) |
| || file.starts_with(self.target.dll_prefix.as_ref()) |
| && file.ends_with(self.target.dll_suffix.as_ref()) |
| { |
| // Make sure there's at most one rlib and at most one dylib. |
| // Note to take care and match against the non-canonicalized name: |
| // some systems save build artifacts into content-addressed stores |
| // that do not preserve extensions, and then link to them using |
| // e.g. symbolic links. If we canonicalize too early, we resolve |
| // the symlink, the file type is lost and we might treat rlibs and |
| // rmetas as dylibs. |
| let loc_canon = loc.canonicalized().clone(); |
| let loc = loc.original(); |
| if loc.file_name().unwrap().to_str().unwrap().ends_with(".rlib") { |
| rlibs.insert(loc_canon, PathKind::ExternFlag); |
| } else if loc.file_name().unwrap().to_str().unwrap().ends_with(".rmeta") { |
| rmetas.insert(loc_canon, PathKind::ExternFlag); |
| } else { |
| dylibs.insert(loc_canon, PathKind::ExternFlag); |
| } |
| } else { |
| self.crate_rejections |
| .via_filename |
| .push(CrateMismatch { path: loc.original().clone(), got: String::new() }); |
| } |
| } |
| |
| // Extract the dylib/rlib/rmeta triple. |
| Ok(self.extract_lib(rlibs, rmetas, dylibs)?.map(|(_, lib)| lib)) |
| } |
| |
| pub(crate) fn into_error(self, root: Option<CratePaths>) -> CrateError { |
| CrateError::LocatorCombined(Box::new(CombinedLocatorError { |
| crate_name: self.crate_name, |
| root, |
| triple: self.triple, |
| dll_prefix: self.target.dll_prefix.to_string(), |
| dll_suffix: self.target.dll_suffix.to_string(), |
| crate_rejections: self.crate_rejections, |
| })) |
| } |
| } |
| |
| fn get_metadata_section<'p>( |
| target: &Target, |
| flavor: CrateFlavor, |
| filename: &'p Path, |
| loader: &dyn MetadataLoader, |
| ) -> Result<MetadataBlob, MetadataError<'p>> { |
| if !filename.exists() { |
| return Err(MetadataError::NotPresent(filename)); |
| } |
| let raw_bytes = match flavor { |
| CrateFlavor::Rlib => { |
| loader.get_rlib_metadata(target, filename).map_err(MetadataError::LoadFailure)? |
| } |
| CrateFlavor::Dylib => { |
| let buf = |
| loader.get_dylib_metadata(target, filename).map_err(MetadataError::LoadFailure)?; |
| // The header is uncompressed |
| let header_len = METADATA_HEADER.len(); |
| // header + u32 length of data |
| let data_start = header_len + 4; |
| |
| debug!("checking {} bytes of metadata-version stamp", header_len); |
| let header = &buf[..cmp::min(header_len, buf.len())]; |
| if header != METADATA_HEADER { |
| return Err(MetadataError::LoadFailure(format!( |
| "invalid metadata version found: {}", |
| filename.display() |
| ))); |
| } |
| |
| // Length of the compressed stream - this allows linkers to pad the section if they want |
| let Ok(len_bytes) = |
| <[u8; 4]>::try_from(&buf[header_len..cmp::min(data_start, buf.len())]) |
| else { |
| return Err(MetadataError::LoadFailure( |
| "invalid metadata length found".to_string(), |
| )); |
| }; |
| let compressed_len = u32::from_be_bytes(len_bytes) as usize; |
| |
| // Header is okay -> inflate the actual metadata |
| let compressed_bytes = buf.slice(|buf| &buf[data_start..(data_start + compressed_len)]); |
| if &compressed_bytes[..cmp::min(METADATA_HEADER.len(), compressed_bytes.len())] |
| == METADATA_HEADER |
| { |
| // The metadata was not actually compressed. |
| compressed_bytes |
| } else { |
| debug!("inflating {} bytes of compressed metadata", compressed_bytes.len()); |
| // Assume the decompressed data will be at least the size of the compressed data, so we |
| // don't have to grow the buffer as much. |
| let mut inflated = Vec::with_capacity(compressed_bytes.len()); |
| FrameDecoder::new(&*compressed_bytes).read_to_end(&mut inflated).map_err(|_| { |
| MetadataError::LoadFailure(format!( |
| "failed to decompress metadata: {}", |
| filename.display() |
| )) |
| })?; |
| |
| slice_owned(inflated, Deref::deref) |
| } |
| } |
| CrateFlavor::Rmeta => { |
| // mmap the file, because only a small fraction of it is read. |
| let file = std::fs::File::open(filename).map_err(|_| { |
| MetadataError::LoadFailure(format!( |
| "failed to open rmeta metadata: '{}'", |
| filename.display() |
| )) |
| })?; |
| let mmap = unsafe { Mmap::map(file) }; |
| let mmap = mmap.map_err(|_| { |
| MetadataError::LoadFailure(format!( |
| "failed to mmap rmeta metadata: '{}'", |
| filename.display() |
| )) |
| })?; |
| |
| slice_owned(mmap, Deref::deref) |
| } |
| }; |
| let blob = MetadataBlob(raw_bytes); |
| if blob.is_compatible() { |
| Ok(blob) |
| } else { |
| Err(MetadataError::LoadFailure(format!( |
| "invalid metadata version found: {}", |
| filename.display() |
| ))) |
| } |
| } |
| |
| /// A diagnostic function for dumping crate metadata to an output stream. |
| pub fn list_file_metadata( |
| target: &Target, |
| path: &Path, |
| metadata_loader: &dyn MetadataLoader, |
| out: &mut dyn Write, |
| ls_kinds: &[String], |
| ) -> IoResult<()> { |
| let flavor = get_flavor_from_path(path); |
| match get_metadata_section(target, flavor, path, metadata_loader) { |
| Ok(metadata) => metadata.list_crate_metadata(out, ls_kinds), |
| Err(msg) => write!(out, "{msg}\n"), |
| } |
| } |
| |
| fn get_flavor_from_path(path: &Path) -> CrateFlavor { |
| let filename = path.file_name().unwrap().to_str().unwrap(); |
| |
| if filename.ends_with(".rlib") { |
| CrateFlavor::Rlib |
| } else if filename.ends_with(".rmeta") { |
| CrateFlavor::Rmeta |
| } else { |
| CrateFlavor::Dylib |
| } |
| } |
| |
| // ------------------------------------------ Error reporting ------------------------------------- |
| |
| #[derive(Clone)] |
| struct CrateMismatch { |
| path: PathBuf, |
| got: String, |
| } |
| |
| #[derive(Clone, Default)] |
| struct CrateRejections { |
| via_hash: Vec<CrateMismatch>, |
| via_triple: Vec<CrateMismatch>, |
| via_kind: Vec<CrateMismatch>, |
| via_version: Vec<CrateMismatch>, |
| via_filename: Vec<CrateMismatch>, |
| via_invalid: Vec<CrateMismatch>, |
| } |
| |
| /// Candidate rejection reasons collected during crate search. |
| /// If no candidate is accepted, then these reasons are presented to the user, |
| /// otherwise they are ignored. |
| pub(crate) struct CombinedLocatorError { |
| crate_name: Symbol, |
| root: Option<CratePaths>, |
| triple: TargetTriple, |
| dll_prefix: String, |
| dll_suffix: String, |
| crate_rejections: CrateRejections, |
| } |
| |
| pub(crate) enum CrateError { |
| NonAsciiName(Symbol), |
| ExternLocationNotExist(Symbol, PathBuf), |
| ExternLocationNotFile(Symbol, PathBuf), |
| MultipleCandidates(Symbol, CrateFlavor, Vec<PathBuf>), |
| SymbolConflictsCurrent(Symbol), |
| StableCrateIdCollision(Symbol, Symbol), |
| DlOpen(String), |
| DlSym(String), |
| LocatorCombined(Box<CombinedLocatorError>), |
| NotFound(Symbol), |
| } |
| |
| enum MetadataError<'a> { |
| /// The file was missing. |
| NotPresent(&'a Path), |
| /// The file was present and invalid. |
| LoadFailure(String), |
| } |
| |
| impl fmt::Display for MetadataError<'_> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| MetadataError::NotPresent(filename) => { |
| f.write_str(&format!("no such file: '{}'", filename.display())) |
| } |
| MetadataError::LoadFailure(msg) => f.write_str(msg), |
| } |
| } |
| } |
| |
| impl CrateError { |
| pub(crate) fn report(self, sess: &Session, span: Span, missing_core: bool) { |
| match self { |
| CrateError::NonAsciiName(crate_name) => { |
| sess.emit_err(errors::NonAsciiName { span, crate_name }); |
| } |
| CrateError::ExternLocationNotExist(crate_name, loc) => { |
| sess.emit_err(errors::ExternLocationNotExist { span, crate_name, location: &loc }); |
| } |
| CrateError::ExternLocationNotFile(crate_name, loc) => { |
| sess.emit_err(errors::ExternLocationNotFile { span, crate_name, location: &loc }); |
| } |
| CrateError::MultipleCandidates(crate_name, flavor, candidates) => { |
| sess.emit_err(errors::MultipleCandidates { span, crate_name, flavor, candidates }); |
| } |
| CrateError::SymbolConflictsCurrent(root_name) => { |
| sess.emit_err(errors::SymbolConflictsCurrent { span, crate_name: root_name }); |
| } |
| CrateError::StableCrateIdCollision(crate_name0, crate_name1) => { |
| sess.emit_err(errors::StableCrateIdCollision { span, crate_name0, crate_name1 }); |
| } |
| CrateError::DlOpen(s) | CrateError::DlSym(s) => { |
| sess.emit_err(errors::DlError { span, err: s }); |
| } |
| CrateError::LocatorCombined(locator) => { |
| let crate_name = locator.crate_name; |
| let add_info = match &locator.root { |
| None => String::new(), |
| Some(r) => format!(" which `{}` depends on", r.name), |
| }; |
| if !locator.crate_rejections.via_filename.is_empty() { |
| let mismatches = locator.crate_rejections.via_filename.iter(); |
| for CrateMismatch { path, .. } in mismatches { |
| sess.emit_err(errors::CrateLocationUnknownType { |
| span, |
| path: &path, |
| crate_name, |
| }); |
| sess.emit_err(errors::LibFilenameForm { |
| span, |
| dll_prefix: &locator.dll_prefix, |
| dll_suffix: &locator.dll_suffix, |
| }); |
| } |
| } |
| let mut found_crates = String::new(); |
| if !locator.crate_rejections.via_hash.is_empty() { |
| let mismatches = locator.crate_rejections.via_hash.iter(); |
| for CrateMismatch { path, .. } in mismatches { |
| found_crates.push_str(&format!( |
| "\ncrate `{}`: {}", |
| crate_name, |
| path.display() |
| )); |
| } |
| if let Some(r) = locator.root { |
| for path in r.source.paths() { |
| found_crates.push_str(&format!( |
| "\ncrate `{}`: {}", |
| r.name, |
| path.display() |
| )); |
| } |
| } |
| sess.emit_err(errors::NewerCrateVersion { |
| span, |
| crate_name: crate_name, |
| add_info, |
| found_crates, |
| }); |
| } else if !locator.crate_rejections.via_triple.is_empty() { |
| let mismatches = locator.crate_rejections.via_triple.iter(); |
| for CrateMismatch { path, got } in mismatches { |
| found_crates.push_str(&format!( |
| "\ncrate `{}`, target triple {}: {}", |
| crate_name, |
| got, |
| path.display(), |
| )); |
| } |
| sess.emit_err(errors::NoCrateWithTriple { |
| span, |
| crate_name, |
| locator_triple: locator.triple.triple(), |
| add_info, |
| found_crates, |
| }); |
| } else if !locator.crate_rejections.via_kind.is_empty() { |
| let mismatches = locator.crate_rejections.via_kind.iter(); |
| for CrateMismatch { path, .. } in mismatches { |
| found_crates.push_str(&format!( |
| "\ncrate `{}`: {}", |
| crate_name, |
| path.display() |
| )); |
| } |
| sess.emit_err(errors::FoundStaticlib { |
| span, |
| crate_name, |
| add_info, |
| found_crates, |
| }); |
| } else if !locator.crate_rejections.via_version.is_empty() { |
| let mismatches = locator.crate_rejections.via_version.iter(); |
| for CrateMismatch { path, got } in mismatches { |
| found_crates.push_str(&format!( |
| "\ncrate `{}` compiled by {}: {}", |
| crate_name, |
| got, |
| path.display(), |
| )); |
| } |
| sess.emit_err(errors::IncompatibleRustc { |
| span, |
| crate_name, |
| add_info, |
| found_crates, |
| rustc_version: rustc_version(sess.cfg_version), |
| }); |
| } else if !locator.crate_rejections.via_invalid.is_empty() { |
| let mut crate_rejections = Vec::new(); |
| for CrateMismatch { path: _, got } in locator.crate_rejections.via_invalid { |
| crate_rejections.push(got); |
| } |
| sess.emit_err(errors::InvalidMetadataFiles { |
| span, |
| crate_name, |
| add_info, |
| crate_rejections, |
| }); |
| } else { |
| sess.emit_err(errors::CannotFindCrate { |
| span, |
| crate_name, |
| add_info, |
| missing_core, |
| current_crate: sess |
| .opts |
| .crate_name |
| .clone() |
| .unwrap_or("<unknown>".to_string()), |
| is_nightly_build: sess.is_nightly_build(), |
| profiler_runtime: Symbol::intern(&sess.opts.unstable_opts.profiler_runtime), |
| locator_triple: locator.triple, |
| is_ui_testing: sess.opts.unstable_opts.ui_testing, |
| }); |
| } |
| } |
| CrateError::NotFound(crate_name) => { |
| sess.emit_err(errors::CannotFindCrate { |
| span, |
| crate_name, |
| add_info: String::new(), |
| missing_core, |
| current_crate: sess.opts.crate_name.clone().unwrap_or("<unknown>".to_string()), |
| is_nightly_build: sess.is_nightly_build(), |
| profiler_runtime: Symbol::intern(&sess.opts.unstable_opts.profiler_runtime), |
| locator_triple: sess.opts.target_triple.clone(), |
| is_ui_testing: sess.opts.unstable_opts.ui_testing, |
| }); |
| } |
| } |
| } |
| } |
