rustc_codegen_ssa/
lib.rs

1// tidy-alphabetical-start
2#![allow(internal_features)]
3#![allow(rustc::diagnostic_outside_of_impl)]
4#![allow(rustc::untranslatable_diagnostic)]
5#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
6#![doc(rust_logo)]
7#![feature(assert_matches)]
8#![feature(box_patterns)]
9#![feature(file_buffered)]
10#![feature(if_let_guard)]
11#![feature(negative_impls)]
12#![feature(rustdoc_internals)]
13#![feature(string_from_utf8_lossy_owned)]
14#![feature(trait_alias)]
15#![feature(try_blocks)]
16#![recursion_limit = "256"]
17// tidy-alphabetical-end
18
19//! This crate contains codegen code that is used by all codegen backends (LLVM and others).
20//! The backend-agnostic functions of this crate use functions defined in various traits that
21//! have to be implemented by each backend.
22
23use std::collections::BTreeSet;
24use std::io;
25use std::path::{Path, PathBuf};
26use std::sync::Arc;
27
28use rustc_ast as ast;
29use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
30use rustc_data_structures::unord::UnordMap;
31use rustc_hir::CRATE_HIR_ID;
32use rustc_hir::def_id::CrateNum;
33use rustc_macros::{Decodable, Encodable, HashStable};
34use rustc_middle::dep_graph::WorkProduct;
35use rustc_middle::lint::LevelAndSource;
36use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
37use rustc_middle::middle::dependency_format::Dependencies;
38use rustc_middle::middle::exported_symbols::SymbolExportKind;
39use rustc_middle::ty::TyCtxt;
40use rustc_middle::util::Providers;
41use rustc_serialize::opaque::{FileEncoder, MemDecoder};
42use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
43use rustc_session::Session;
44use rustc_session::config::{CrateType, OutputFilenames, OutputType, RUST_CGU_EXT};
45use rustc_session::cstore::{self, CrateSource};
46use rustc_session::lint::builtin::LINKER_MESSAGES;
47use rustc_session::utils::NativeLibKind;
48use rustc_span::Symbol;
49
50pub mod assert_module_sources;
51pub mod back;
52pub mod base;
53pub mod codegen_attrs;
54pub mod common;
55pub mod debuginfo;
56pub mod errors;
57pub mod meth;
58pub mod mir;
59pub mod mono_item;
60pub mod size_of_val;
61pub mod target_features;
62pub mod traits;
63
64rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
65
66pub struct ModuleCodegen<M> {
67    /// The name of the module. When the crate may be saved between
68    /// compilations, incremental compilation requires that name be
69    /// unique amongst **all** crates. Therefore, it should contain
70    /// something unique to this crate (e.g., a module path) as well
71    /// as the crate name and disambiguator.
72    /// We currently generate these names via CodegenUnit::build_cgu_name().
73    pub name: String,
74    pub module_llvm: M,
75    pub kind: ModuleKind,
76    /// Saving the ThinLTO buffer for embedding in the object file.
77    pub thin_lto_buffer: Option<Vec<u8>>,
78}
79
80impl<M> ModuleCodegen<M> {
81    pub fn new_regular(name: impl Into<String>, module: M) -> Self {
82        Self {
83            name: name.into(),
84            module_llvm: module,
85            kind: ModuleKind::Regular,
86            thin_lto_buffer: None,
87        }
88    }
89
90    pub fn new_allocator(name: impl Into<String>, module: M) -> Self {
91        Self {
92            name: name.into(),
93            module_llvm: module,
94            kind: ModuleKind::Allocator,
95            thin_lto_buffer: None,
96        }
97    }
98
99    pub fn into_compiled_module(
100        self,
101        emit_obj: bool,
102        emit_dwarf_obj: bool,
103        emit_bc: bool,
104        emit_asm: bool,
105        emit_ir: bool,
106        outputs: &OutputFilenames,
107        invocation_temp: Option<&str>,
108    ) -> CompiledModule {
109        let object = emit_obj
110            .then(|| outputs.temp_path_for_cgu(OutputType::Object, &self.name, invocation_temp));
111        let dwarf_object =
112            emit_dwarf_obj.then(|| outputs.temp_path_dwo_for_cgu(&self.name, invocation_temp));
113        let bytecode = emit_bc
114            .then(|| outputs.temp_path_for_cgu(OutputType::Bitcode, &self.name, invocation_temp));
115        let assembly = emit_asm
116            .then(|| outputs.temp_path_for_cgu(OutputType::Assembly, &self.name, invocation_temp));
117        let llvm_ir = emit_ir.then(|| {
118            outputs.temp_path_for_cgu(OutputType::LlvmAssembly, &self.name, invocation_temp)
119        });
120
121        CompiledModule {
122            name: self.name.clone(),
123            kind: self.kind,
124            object,
125            dwarf_object,
126            bytecode,
127            assembly,
128            llvm_ir,
129            links_from_incr_cache: Vec::new(),
130        }
131    }
132}
133
134#[derive(Debug, Encodable, Decodable)]
135pub struct CompiledModule {
136    pub name: String,
137    pub kind: ModuleKind,
138    pub object: Option<PathBuf>,
139    pub dwarf_object: Option<PathBuf>,
140    pub bytecode: Option<PathBuf>,
141    pub assembly: Option<PathBuf>, // --emit=asm
142    pub llvm_ir: Option<PathBuf>,  // --emit=llvm-ir, llvm-bc is in bytecode
143    pub links_from_incr_cache: Vec<PathBuf>,
144}
145
146impl CompiledModule {
147    /// Call `emit` function with every artifact type currently compiled
148    pub fn for_each_output(&self, mut emit: impl FnMut(&Path, OutputType)) {
149        if let Some(path) = self.object.as_deref() {
150            emit(path, OutputType::Object);
151        }
152        if let Some(path) = self.bytecode.as_deref() {
153            emit(path, OutputType::Bitcode);
154        }
155        if let Some(path) = self.llvm_ir.as_deref() {
156            emit(path, OutputType::LlvmAssembly);
157        }
158        if let Some(path) = self.assembly.as_deref() {
159            emit(path, OutputType::Assembly);
160        }
161    }
162}
163
164pub(crate) struct CachedModuleCodegen {
165    pub name: String,
166    pub source: WorkProduct,
167}
168
169#[derive(Copy, Clone, Debug, PartialEq, Encodable, Decodable)]
170pub enum ModuleKind {
171    Regular,
172    Metadata,
173    Allocator,
174}
175
176bitflags::bitflags! {
177    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
178    pub struct MemFlags: u8 {
179        const VOLATILE = 1 << 0;
180        const NONTEMPORAL = 1 << 1;
181        const UNALIGNED = 1 << 2;
182    }
183}
184
185#[derive(Clone, Debug, Encodable, Decodable, HashStable)]
186pub struct NativeLib {
187    pub kind: NativeLibKind,
188    pub name: Symbol,
189    pub filename: Option<Symbol>,
190    pub cfg: Option<ast::MetaItemInner>,
191    pub verbatim: bool,
192    pub dll_imports: Vec<cstore::DllImport>,
193}
194
195impl From<&cstore::NativeLib> for NativeLib {
196    fn from(lib: &cstore::NativeLib) -> Self {
197        NativeLib {
198            kind: lib.kind,
199            filename: lib.filename,
200            name: lib.name,
201            cfg: lib.cfg.clone(),
202            verbatim: lib.verbatim.unwrap_or(false),
203            dll_imports: lib.dll_imports.clone(),
204        }
205    }
206}
207
208/// Misc info we load from metadata to persist beyond the tcx.
209///
210/// Note: though `CrateNum` is only meaningful within the same tcx, information within `CrateInfo`
211/// is self-contained. `CrateNum` can be viewed as a unique identifier within a `CrateInfo`, where
212/// `used_crate_source` contains all `CrateSource` of the dependents, and maintains a mapping from
213/// identifiers (`CrateNum`) to `CrateSource`. The other fields map `CrateNum` to the crate's own
214/// additional properties, so that effectively we can retrieve each dependent crate's `CrateSource`
215/// and the corresponding properties without referencing information outside of a `CrateInfo`.
216#[derive(Debug, Encodable, Decodable)]
217pub struct CrateInfo {
218    pub target_cpu: String,
219    pub target_features: Vec<String>,
220    pub crate_types: Vec<CrateType>,
221    pub exported_symbols: UnordMap<CrateType, Vec<String>>,
222    pub linked_symbols: FxIndexMap<CrateType, Vec<(String, SymbolExportKind)>>,
223    pub local_crate_name: Symbol,
224    pub compiler_builtins: Option<CrateNum>,
225    pub profiler_runtime: Option<CrateNum>,
226    pub is_no_builtins: FxHashSet<CrateNum>,
227    pub native_libraries: FxIndexMap<CrateNum, Vec<NativeLib>>,
228    pub crate_name: UnordMap<CrateNum, Symbol>,
229    pub used_libraries: Vec<NativeLib>,
230    pub used_crate_source: UnordMap<CrateNum, Arc<CrateSource>>,
231    pub used_crates: Vec<CrateNum>,
232    pub dependency_formats: Arc<Dependencies>,
233    pub windows_subsystem: Option<String>,
234    pub natvis_debugger_visualizers: BTreeSet<DebuggerVisualizerFile>,
235    pub lint_levels: CodegenLintLevels,
236}
237
238/// Target-specific options that get set in `cfg(...)`.
239///
240/// RUSTC_SPECIFIC_FEATURES should be skipped here, those are handled outside codegen.
241pub struct TargetConfig {
242    /// Options to be set in `cfg(target_features)`.
243    pub target_features: Vec<Symbol>,
244    /// Options to be set in `cfg(target_features)`, but including unstable features.
245    pub unstable_target_features: Vec<Symbol>,
246    /// Option for `cfg(target_has_reliable_f16)`, true if `f16` basic arithmetic works.
247    pub has_reliable_f16: bool,
248    /// Option for `cfg(target_has_reliable_f16_math)`, true if `f16` math calls work.
249    pub has_reliable_f16_math: bool,
250    /// Option for `cfg(target_has_reliable_f128)`, true if `f128` basic arithmetic works.
251    pub has_reliable_f128: bool,
252    /// Option for `cfg(target_has_reliable_f128_math)`, true if `f128` math calls work.
253    pub has_reliable_f128_math: bool,
254}
255
256#[derive(Encodable, Decodable)]
257pub struct CodegenResults {
258    pub modules: Vec<CompiledModule>,
259    pub allocator_module: Option<CompiledModule>,
260    pub metadata_module: Option<CompiledModule>,
261    pub metadata: rustc_metadata::EncodedMetadata,
262    pub crate_info: CrateInfo,
263}
264
265pub enum CodegenErrors {
266    WrongFileType,
267    EmptyVersionNumber,
268    EncodingVersionMismatch { version_array: String, rlink_version: u32 },
269    RustcVersionMismatch { rustc_version: String },
270    CorruptFile,
271}
272
273pub fn provide(providers: &mut Providers) {
274    crate::back::symbol_export::provide(providers);
275    crate::base::provide(providers);
276    crate::target_features::provide(providers);
277    crate::codegen_attrs::provide(providers);
278    providers.queries.global_backend_features = |_tcx: TyCtxt<'_>, ()| vec![];
279}
280
281/// Checks if the given filename ends with the `.rcgu.o` extension that `rustc`
282/// uses for the object files it generates.
283pub fn looks_like_rust_object_file(filename: &str) -> bool {
284    let path = Path::new(filename);
285    let ext = path.extension().and_then(|s| s.to_str());
286    if ext != Some(OutputType::Object.extension()) {
287        // The file name does not end with ".o", so it can't be an object file.
288        return false;
289    }
290
291    // Strip the ".o" at the end
292    let ext2 = path.file_stem().and_then(|s| Path::new(s).extension()).and_then(|s| s.to_str());
293
294    // Check if the "inner" extension
295    ext2 == Some(RUST_CGU_EXT)
296}
297
298const RLINK_VERSION: u32 = 1;
299const RLINK_MAGIC: &[u8] = b"rustlink";
300
301impl CodegenResults {
302    pub fn serialize_rlink(
303        sess: &Session,
304        rlink_file: &Path,
305        codegen_results: &CodegenResults,
306        outputs: &OutputFilenames,
307    ) -> Result<usize, io::Error> {
308        let mut encoder = FileEncoder::new(rlink_file)?;
309        encoder.emit_raw_bytes(RLINK_MAGIC);
310        // `emit_raw_bytes` is used to make sure that the version representation does not depend on
311        // Encoder's inner representation of `u32`.
312        encoder.emit_raw_bytes(&RLINK_VERSION.to_be_bytes());
313        encoder.emit_str(sess.cfg_version);
314        Encodable::encode(codegen_results, &mut encoder);
315        Encodable::encode(outputs, &mut encoder);
316        encoder.finish().map_err(|(_path, err)| err)
317    }
318
319    pub fn deserialize_rlink(
320        sess: &Session,
321        data: Vec<u8>,
322    ) -> Result<(Self, OutputFilenames), CodegenErrors> {
323        // The Decodable machinery is not used here because it panics if the input data is invalid
324        // and because its internal representation may change.
325        if !data.starts_with(RLINK_MAGIC) {
326            return Err(CodegenErrors::WrongFileType);
327        }
328        let data = &data[RLINK_MAGIC.len()..];
329        if data.len() < 4 {
330            return Err(CodegenErrors::EmptyVersionNumber);
331        }
332
333        let mut version_array: [u8; 4] = Default::default();
334        version_array.copy_from_slice(&data[..4]);
335        if u32::from_be_bytes(version_array) != RLINK_VERSION {
336            return Err(CodegenErrors::EncodingVersionMismatch {
337                version_array: String::from_utf8_lossy(&version_array).to_string(),
338                rlink_version: RLINK_VERSION,
339            });
340        }
341
342        let Ok(mut decoder) = MemDecoder::new(&data[4..], 0) else {
343            return Err(CodegenErrors::CorruptFile);
344        };
345        let rustc_version = decoder.read_str();
346        if rustc_version != sess.cfg_version {
347            return Err(CodegenErrors::RustcVersionMismatch {
348                rustc_version: rustc_version.to_string(),
349            });
350        }
351
352        let codegen_results = CodegenResults::decode(&mut decoder);
353        let outputs = OutputFilenames::decode(&mut decoder);
354        Ok((codegen_results, outputs))
355    }
356}
357
358/// A list of lint levels used in codegen.
359///
360/// When using `-Z link-only`, we don't have access to the tcx and must work
361/// solely from the `.rlink` file. `Lint`s are defined too early to be encodeable.
362/// Instead, encode exactly the information we need.
363#[derive(Copy, Clone, Debug, Encodable, Decodable)]
364pub struct CodegenLintLevels {
365    linker_messages: LevelAndSource,
366}
367
368impl CodegenLintLevels {
369    pub fn from_tcx(tcx: TyCtxt<'_>) -> Self {
370        Self { linker_messages: tcx.lint_level_at_node(LINKER_MESSAGES, CRATE_HIR_ID) }
371    }
372}
rustc_codegen_ssa/lib.rs

rustc_codegen_ssa/
lib.rs
