compiler/rustc_codegen_ssa/src/lib.rs

   1 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
   2 #![feature(box_patterns)]
   3 #![feature(try_blocks)]
   4 #![feature(let_else)]
   5 #![feature(once_cell)]
   6 #![feature(associated_type_bounds)]
   7 #![feature(strict_provenance)]
   8 #![feature(int_roundings)]
   9 #![recursion_limit = "256"]
  10 #![allow(rustc::potential_query_instability)]
  11
  12 //! This crate contains codegen code that is used by all codegen backends (LLVM and others).
  13 //! The backend-agnostic functions of this crate use functions defined in various traits that
  14 //! have to be implemented by each backends.
  15
  16 #[macro_use]
  17 extern crate rustc_macros;
  18 #[macro_use]
  19 extern crate tracing;
  20 #[macro_use]
  21 extern crate rustc_middle;
  22
  23 use rustc_ast as ast;
  24 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
  25 use rustc_data_structures::sync::Lrc;
  26 use rustc_hir::def_id::CrateNum;
  27 use rustc_hir::LangItem;
  28 use rustc_middle::dep_graph::WorkProduct;
  29 use rustc_middle::middle::dependency_format::Dependencies;
  30 use rustc_middle::middle::exported_symbols::SymbolExportKind;
  31 use rustc_middle::ty::query::{ExternProviders, Providers};
  32 use rustc_serialize::opaque::{MemDecoder, MemEncoder};
  33 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
  34 use rustc_session::config::{CrateType, OutputFilenames, OutputType, RUST_CGU_EXT};
  35 use rustc_session::cstore::{self, CrateSource};
  36 use rustc_session::utils::NativeLibKind;
  37 use rustc_span::symbol::Symbol;
  38 use rustc_span::DebuggerVisualizerFile;
  39 use std::collections::BTreeSet;
  40 use std::path::{Path, PathBuf};
  41
  42 pub mod back;
  43 pub mod base;
  44 pub mod common;
  45 pub mod coverageinfo;
  46 pub mod debuginfo;
  47 pub mod glue;
  48 pub mod meth;
  49 pub mod mir;
  50 pub mod mono_item;
  51 pub mod target_features;
  52 pub mod traits;
  53
  54 pub struct ModuleCodegen<M> {
  55     /// The name of the module. When the crate may be saved between
  56     /// compilations, incremental compilation requires that name be
  57     /// unique amongst **all** crates. Therefore, it should contain
  58     /// something unique to this crate (e.g., a module path) as well
  59     /// as the crate name and disambiguator.
  60     /// We currently generate these names via CodegenUnit::build_cgu_name().
  61     pub name: String,
  62     pub module_llvm: M,
  63     pub kind: ModuleKind,
  64 }
  65
  66 // FIXME(eddyb) maybe include the crate name in this?
  67 pub const METADATA_FILENAME: &str = "lib.rmeta";
  68
  69 impl<M> ModuleCodegen<M> {
  70     pub fn into_compiled_module(
  71         self,
  72         emit_obj: bool,
  73         emit_dwarf_obj: bool,
  74         emit_bc: bool,
  75         outputs: &OutputFilenames,
  76     ) -> CompiledModule {
  77         let object = emit_obj.then(|| outputs.temp_path(OutputType::Object, Some(&self.name)));
  78         let dwarf_object = emit_dwarf_obj.then(|| outputs.temp_path_dwo(Some(&self.name)));
  79         let bytecode = emit_bc.then(|| outputs.temp_path(OutputType::Bitcode, Some(&self.name)));
  80
  81         CompiledModule { name: self.name.clone(), kind: self.kind, object, dwarf_object, bytecode }
  82     }
  83 }
  84
  85 #[derive(Debug, Encodable, Decodable)]
  86 pub struct CompiledModule {
  87     pub name: String,
  88     pub kind: ModuleKind,
  89     pub object: Option<PathBuf>,
  90     pub dwarf_object: Option<PathBuf>,
  91     pub bytecode: Option<PathBuf>,
  92 }
  93
  94 pub struct CachedModuleCodegen {
  95     pub name: String,
  96     pub source: WorkProduct,
  97 }
  98
  99 #[derive(Copy, Clone, Debug, PartialEq, Encodable, Decodable)]
 100 pub enum ModuleKind {
 101     Regular,
 102     Metadata,
 103     Allocator,
 104 }
 105
 106 bitflags::bitflags! {
 107     pub struct MemFlags: u8 {
 108         const VOLATILE = 1 << 0;
 109         const NONTEMPORAL = 1 << 1;
 110         const UNALIGNED = 1 << 2;
 111     }
 112 }
 113
 114 #[derive(Clone, Debug, Encodable, Decodable, HashStable)]
 115 pub struct NativeLib {
 116     pub kind: NativeLibKind,
 117     pub name: Option<Symbol>,
 118     pub cfg: Option<ast::MetaItem>,
 119     pub verbatim: Option<bool>,
 120     pub dll_imports: Vec<cstore::DllImport>,
 121 }
 122
 123 impl From<&cstore::NativeLib> for NativeLib {
 124     fn from(lib: &cstore::NativeLib) -> Self {
 125         NativeLib {
 126             kind: lib.kind,
 127             name: lib.name,
 128             cfg: lib.cfg.clone(),
 129             verbatim: lib.verbatim,
 130             dll_imports: lib.dll_imports.clone(),
 131         }
 132     }
 133 }
 134
 135 /// Misc info we load from metadata to persist beyond the tcx.
 136 ///
 137 /// Note: though `CrateNum` is only meaningful within the same tcx, information within `CrateInfo`
 138 /// is self-contained. `CrateNum` can be viewed as a unique identifier within a `CrateInfo`, where
 139 /// `used_crate_source` contains all `CrateSource` of the dependents, and maintains a mapping from
 140 /// identifiers (`CrateNum`) to `CrateSource`. The other fields map `CrateNum` to the crate's own
 141 /// additional properties, so that effectively we can retrieve each dependent crate's `CrateSource`
 142 /// and the corresponding properties without referencing information outside of a `CrateInfo`.
 143 #[derive(Debug, Encodable, Decodable)]
 144 pub struct CrateInfo {
 145     pub target_cpu: String,
 146     pub exported_symbols: FxHashMap<CrateType, Vec<String>>,
 147     pub linked_symbols: FxHashMap<CrateType, Vec<(String, SymbolExportKind)>>,
 148     pub local_crate_name: Symbol,
 149     pub compiler_builtins: Option<CrateNum>,
 150     pub profiler_runtime: Option<CrateNum>,
 151     pub is_no_builtins: FxHashSet<CrateNum>,
 152     pub native_libraries: FxHashMap<CrateNum, Vec<NativeLib>>,
 153     pub crate_name: FxHashMap<CrateNum, Symbol>,
 154     pub used_libraries: Vec<NativeLib>,
 155     pub used_crate_source: FxHashMap<CrateNum, Lrc<CrateSource>>,
 156     pub used_crates: Vec<CrateNum>,
 157     pub lang_item_to_crate: FxHashMap<LangItem, CrateNum>,
 158     pub missing_lang_items: FxHashMap<CrateNum, Vec<LangItem>>,
 159     pub dependency_formats: Lrc<Dependencies>,
 160     pub windows_subsystem: Option<String>,
 161     pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
 162 }
 163
 164 #[derive(Encodable, Decodable)]
 165 pub struct CodegenResults {
 166     pub modules: Vec<CompiledModule>,
 167     pub allocator_module: Option<CompiledModule>,
 168     pub metadata_module: Option<CompiledModule>,
 169     pub metadata: rustc_metadata::EncodedMetadata,
 170     pub crate_info: CrateInfo,
 171 }
 172
 173 pub fn provide(providers: &mut Providers) {
 174     crate::back::symbol_export::provide(providers);
 175     crate::base::provide(providers);
 176     crate::target_features::provide(providers);
 177 }
 178
 179 pub fn provide_extern(providers: &mut ExternProviders) {
 180     crate::back::symbol_export::provide_extern(providers);
 181 }
 182
 183 /// Checks if the given filename ends with the `.rcgu.o` extension that `rustc`
 184 /// uses for the object files it generates.
 185 pub fn looks_like_rust_object_file(filename: &str) -> bool {
 186     let path = Path::new(filename);
 187     let ext = path.extension().and_then(|s| s.to_str());
 188     if ext != Some(OutputType::Object.extension()) {
 189         // The file name does not end with ".o", so it can't be an object file.
 190         return false;
 191     }
 192
 193     // Strip the ".o" at the end
 194     let ext2 = path.file_stem().and_then(|s| Path::new(s).extension()).and_then(|s| s.to_str());
 195
 196     // Check if the "inner" extension
 197     ext2 == Some(RUST_CGU_EXT)
 198 }
 199
 200 const RLINK_VERSION: u32 = 1;
 201 const RLINK_MAGIC: &[u8] = b"rustlink";
 202
 203 const RUSTC_VERSION: Option<&str> = option_env!("CFG_VERSION");
 204
 205 impl CodegenResults {
 206     pub fn serialize_rlink(codegen_results: &CodegenResults) -> Vec<u8> {
 207         let mut encoder = MemEncoder::new();
 208         encoder.emit_raw_bytes(RLINK_MAGIC);
 209         // `emit_raw_bytes` is used to make sure that the version representation does not depend on
 210         // Encoder's inner representation of `u32`.
 211         encoder.emit_raw_bytes(&RLINK_VERSION.to_be_bytes());
 212         encoder.emit_str(RUSTC_VERSION.unwrap());
 213         Encodable::encode(codegen_results, &mut encoder);
 214         encoder.finish()
 215     }
 216
 217     pub fn deserialize_rlink(data: Vec<u8>) -> Result<Self, String> {
 218         // The Decodable machinery is not used here because it panics if the input data is invalid
 219         // and because its internal representation may change.
 220         if !data.starts_with(RLINK_MAGIC) {
 221             return Err("The input does not look like a .rlink file".to_string());
 222         }
 223         let data = &data[RLINK_MAGIC.len()..];
 224         if data.len() < 4 {
 225             return Err("The input does not contain version number".to_string());
 226         }
 227
 228         let mut version_array: [u8; 4] = Default::default();
 229         version_array.copy_from_slice(&data[..4]);
 230         if u32::from_be_bytes(version_array) != RLINK_VERSION {
 231             return Err(".rlink file was produced with encoding version {version_array}, but the current version is {RLINK_VERSION}".to_string());
 232         }
 233
 234         let mut decoder = MemDecoder::new(&data[4..], 0);
 235         let rustc_version = decoder.read_str();
 236         let current_version = RUSTC_VERSION.unwrap();
 237         if rustc_version != current_version {
 238             return Err(format!(
 239                 ".rlink file was produced by rustc version {rustc_version}, but the current version is {current_version}."
 240             ));
 241         }
 242
 243         let codegen_results = CodegenResults::decode(&mut decoder);
 244         Ok(codegen_results)
 245     }
 246 }