compiler/rustc_codegen_cranelift/src/pretty_clif.rs

   1 //! This module provides the [CommentWriter] which makes it possible
   2 //! to add comments to the written cranelift ir.
   3 //!
   4 //! # Example
   5 //!
   6 //! ```clif
   7 //! test compile
   8 //! target x86_64
   9 //!
  10 //! function u0:0(i64, i64, i64) system_v {
  11 //! ; symbol _ZN119_$LT$example..IsNotEmpty$u20$as$u20$mini_core..FnOnce$LT$$LP$$RF$$u27$a$u20$$RF$$u27$b$u20$$u5b$u16$u5d$$C$$RP$$GT$$GT$9call_once17he85059d5e6a760a0E
  12 //! ; instance Instance { def: Item(DefId(0/0:29 ~ example[8787]::{{impl}}[0]::call_once[0])), substs: [ReErased, ReErased] }
  13 //! ; sig ([IsNotEmpty, (&&[u16],)]; c_variadic: false)->(u8, u8)
  14 //!
  15 //! ; ssa {_2: NOT_SSA, _4: NOT_SSA, _0: NOT_SSA, _3: (empty), _1: NOT_SSA}
  16 //! ; msg   loc.idx    param    pass mode            ssa flags  ty
  17 //! ; ret    _0      = v0       ByRef                NOT_SSA    (u8, u8)
  18 //! ; arg    _1      = v1       ByRef                NOT_SSA    IsNotEmpty
  19 //! ; arg    _2.0    = v2       ByVal(types::I64)    NOT_SSA    &&[u16]
  20 //!
  21 //!     ss0 = explicit_slot 0 ; _1: IsNotEmpty size=0 align=1,8
  22 //!     ss1 = explicit_slot 8 ; _2: (&&[u16],) size=8 align=8,8
  23 //!     ss2 = explicit_slot 8 ; _4: (&&[u16],) size=8 align=8,8
  24 //!     sig0 = (i64, i64, i64) system_v
  25 //!     sig1 = (i64, i64, i64) system_v
  26 //!     fn0 = colocated u0:6 sig1 ; Instance { def: Item(DefId(0/0:31 ~ example[8787]::{{impl}}[1]::call_mut[0])), substs: [ReErased, ReErased] }
  27 //!
  28 //! block0(v0: i64, v1: i64, v2: i64):
  29 //!     v3 = stack_addr.i64 ss0
  30 //!     v4 = stack_addr.i64 ss1
  31 //!     store v2, v4
  32 //!     v5 = stack_addr.i64 ss2
  33 //!     jump block1
  34 //!
  35 //! block1:
  36 //!     nop
  37 //! ; _3 = &mut _1
  38 //! ; _4 = _2
  39 //!     v6 = load.i64 v4
  40 //!     store v6, v5
  41 //! ;
  42 //! ; _0 = const mini_core::FnMut::call_mut(move _3, move _4)
  43 //!     v7 = load.i64 v5
  44 //!     call fn0(v0, v3, v7)
  45 //!     jump block2
  46 //!
  47 //! block2:
  48 //!     nop
  49 //! ;
  50 //! ; return
  51 //!     return
  52 //! }
  53 //! ```
  54
  55 use std::fmt;
  56 use std::io::Write;
  57
  58 use cranelift_codegen::{
  59     entity::SecondaryMap,
  60     ir::entities::AnyEntity,
  61     write::{FuncWriter, PlainWriter},
  62 };
  63
  64 use rustc_middle::ty::layout::FnAbiOf;
  65 use rustc_session::config::{OutputFilenames, OutputType};
  66
  67 use crate::prelude::*;
  68
  69 #[derive(Clone, Debug)]
  70 pub(crate) struct CommentWriter {
  71     enabled: bool,
  72     global_comments: Vec<String>,
  73     entity_comments: FxHashMap<AnyEntity, String>,
  74 }
  75
  76 impl CommentWriter {
  77     pub(crate) fn new<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> Self {
  78         let enabled = should_write_ir(tcx);
  79         let global_comments = if enabled {
  80             vec![
  81                 format!("symbol {}", tcx.symbol_name(instance).name),
  82                 format!("instance {:?}", instance),
  83                 format!(
  84                     "abi {:?}",
  85                     RevealAllLayoutCx(tcx).fn_abi_of_instance(instance, ty::List::empty())
  86                 ),
  87                 String::new(),
  88             ]
  89         } else {
  90             vec![]
  91         };
  92
  93         CommentWriter { enabled, global_comments, entity_comments: FxHashMap::default() }
  94     }
  95 }
  96
  97 impl CommentWriter {
  98     pub(crate) fn enabled(&self) -> bool {
  99         self.enabled
 100     }
 101
 102     pub(crate) fn add_global_comment<S: Into<String>>(&mut self, comment: S) {
 103         debug_assert!(self.enabled);
 104         self.global_comments.push(comment.into());
 105     }
 106
 107     pub(crate) fn add_comment<S: Into<String> + AsRef<str>, E: Into<AnyEntity>>(
 108         &mut self,
 109         entity: E,
 110         comment: S,
 111     ) {
 112         debug_assert!(self.enabled);
 113
 114         use std::collections::hash_map::Entry;
 115         match self.entity_comments.entry(entity.into()) {
 116             Entry::Occupied(mut occ) => {
 117                 occ.get_mut().push('\n');
 118                 occ.get_mut().push_str(comment.as_ref());
 119             }
 120             Entry::Vacant(vac) => {
 121                 vac.insert(comment.into());
 122             }
 123         }
 124     }
 125 }
 126
 127 impl FuncWriter for &'_ CommentWriter {
 128     fn write_preamble(
 129         &mut self,
 130         w: &mut dyn fmt::Write,
 131         func: &Function,
 132     ) -> Result<bool, fmt::Error> {
 133         for comment in &self.global_comments {
 134             if !comment.is_empty() {
 135                 writeln!(w, "; {}", comment)?;
 136             } else {
 137                 writeln!(w)?;
 138             }
 139         }
 140         if !self.global_comments.is_empty() {
 141             writeln!(w)?;
 142         }
 143
 144         self.super_preamble(w, func)
 145     }
 146
 147     fn write_entity_definition(
 148         &mut self,
 149         w: &mut dyn fmt::Write,
 150         _func: &Function,
 151         entity: AnyEntity,
 152         value: &dyn fmt::Display,
 153     ) -> fmt::Result {
 154         write!(w, "    {} = {}", entity, value)?;
 155
 156         if let Some(comment) = self.entity_comments.get(&entity) {
 157             writeln!(w, " ; {}", comment.replace('\n', "\n; "))
 158         } else {
 159             writeln!(w)
 160         }
 161     }
 162
 163     fn write_block_header(
 164         &mut self,
 165         w: &mut dyn fmt::Write,
 166         func: &Function,
 167         block: Block,
 168         indent: usize,
 169     ) -> fmt::Result {
 170         PlainWriter.write_block_header(w, func, block, indent)
 171     }
 172
 173     fn write_instruction(
 174         &mut self,
 175         w: &mut dyn fmt::Write,
 176         func: &Function,
 177         aliases: &SecondaryMap<Value, Vec<Value>>,
 178         inst: Inst,
 179         indent: usize,
 180     ) -> fmt::Result {
 181         PlainWriter.write_instruction(w, func, aliases, inst, indent)?;
 182         if let Some(comment) = self.entity_comments.get(&inst.into()) {
 183             writeln!(w, "; {}", comment.replace('\n', "\n; "))?;
 184         }
 185         Ok(())
 186     }
 187 }
 188
 189 impl FunctionCx<'_, '_, '_> {
 190     pub(crate) fn add_global_comment<S: Into<String>>(&mut self, comment: S) {
 191         self.clif_comments.add_global_comment(comment);
 192     }
 193
 194     pub(crate) fn add_comment<S: Into<String> + AsRef<str>, E: Into<AnyEntity>>(
 195         &mut self,
 196         entity: E,
 197         comment: S,
 198     ) {
 199         self.clif_comments.add_comment(entity, comment);
 200     }
 201 }
 202
 203 pub(crate) fn should_write_ir(tcx: TyCtxt<'_>) -> bool {
 204     tcx.sess.opts.output_types.contains_key(&OutputType::LlvmAssembly)
 205 }
 206
 207 pub(crate) fn write_ir_file(
 208     output_filenames: &OutputFilenames,
 209     name: &str,
 210     write: impl FnOnce(&mut dyn Write) -> std::io::Result<()>,
 211 ) {
 212     let clif_output_dir = output_filenames.with_extension("clif");
 213
 214     match std::fs::create_dir(&clif_output_dir) {
 215         Ok(()) => {}
 216         Err(err) if err.kind() == std::io::ErrorKind::AlreadyExists => {}
 217         res @ Err(_) => res.unwrap(),
 218     }
 219
 220     let clif_file_name = clif_output_dir.join(name);
 221
 222     let res = std::fs::File::create(clif_file_name).and_then(|mut file| write(&mut file));
 223     if let Err(err) = res {
 224         // Using early_warn as no Session is available here
 225         rustc_session::early_warn(
 226             rustc_session::config::ErrorOutputType::default(),
 227             &format!("error writing ir file: {}", err),
 228         );
 229     }
 230 }
 231
 232 pub(crate) fn write_clif_file(
 233     output_filenames: &OutputFilenames,
 234     symbol_name: &str,
 235     postfix: &str,
 236     isa: &dyn cranelift_codegen::isa::TargetIsa,
 237     func: &cranelift_codegen::ir::Function,
 238     mut clif_comments: &CommentWriter,
 239 ) {
 240     // FIXME work around filename too long errors
 241     write_ir_file(output_filenames, &format!("{}.{}.clif", symbol_name, postfix), |file| {
 242         let mut clif = String::new();
 243         cranelift_codegen::write::decorate_function(&mut clif_comments, &mut clif, func).unwrap();
 244
 245         for flag in isa.flags().iter() {
 246             writeln!(file, "set {}", flag)?;
 247         }
 248         write!(file, "target {}", isa.triple().architecture.to_string())?;
 249         for isa_flag in isa.isa_flags().iter() {
 250             write!(file, " {}", isa_flag)?;
 251         }
 252         writeln!(file, "\n")?;
 253         writeln!(file)?;
 254         file.write_all(clif.as_bytes())?;
 255         Ok(())
 256     });
 257 }
 258
 259 impl fmt::Debug for FunctionCx<'_, '_, '_> {
 260     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 261         writeln!(f, "{:?}", self.instance.substs)?;
 262         writeln!(f, "{:?}", self.local_map)?;
 263
 264         let mut clif = String::new();
 265         ::cranelift_codegen::write::decorate_function(
 266             &mut &self.clif_comments,
 267             &mut clif,
 268             &self.bcx.func,
 269         )
 270         .unwrap();
 271         writeln!(f, "\n{}", clif)
 272     }
 273 }