From ba359d8a51d106907332a90c59e1a339b1fc3656 Mon Sep 17 00:00:00 2001 From: Jakob Degen Date: Wed, 3 Aug 2022 04:30:13 -0700 Subject: [PATCH] Add support for custom MIR parsing --- compiler/rustc_borrowck/src/lib.rs | 14 + compiler/rustc_feature/src/active.rs | 2 + compiler/rustc_feature/src/builtin_attrs.rs | 4 + compiler/rustc_middle/src/mir/mod.rs | 59 +++++ .../rustc_mir_build/src/build/custom/mod.rs | 155 +++++++++++ .../rustc_mir_build/src/build/custom/parse.rs | 245 ++++++++++++++++++ .../src/build/custom/parse/instruction.rs | 72 +++++ compiler/rustc_mir_build/src/build/mod.rs | 17 ++ compiler/rustc_mir_build/src/thir/cx/expr.rs | 16 +- compiler/rustc_mir_build/src/thir/cx/mod.rs | 11 +- .../rustc_mir_transform/src/check_unsafety.rs | 8 + .../rustc_mir_transform/src/pass_manager.rs | 71 ++--- compiler/rustc_span/src/symbol.rs | 1 + library/core/src/intrinsics.rs | 3 + library/core/src/intrinsics/mir.rs | 123 +++++++++ .../references.immut_ref.built.after.mir | 14 + .../custom/references.mut_ref.built.after.mir | 14 + .../mir-opt/building/custom/references.rs | 43 +++ .../mir-opt/building/custom/simple_assign.rs | 37 +++ .../simple_assign.simple.built.after.mir | 18 ++ .../simple_assign.simple_ref.built.after.mir | 10 + .../feature-gates/feature-gate-custom_mir.rs | 12 + .../feature-gate-custom_mir.stderr | 11 + 23 files changed, 920 insertions(+), 40 deletions(-) create mode 100644 compiler/rustc_mir_build/src/build/custom/mod.rs create mode 100644 compiler/rustc_mir_build/src/build/custom/parse.rs create mode 100644 compiler/rustc_mir_build/src/build/custom/parse/instruction.rs create mode 100644 library/core/src/intrinsics/mir.rs create mode 100644 src/test/mir-opt/building/custom/references.immut_ref.built.after.mir create mode 100644 src/test/mir-opt/building/custom/references.mut_ref.built.after.mir create mode 100644 src/test/mir-opt/building/custom/references.rs create mode 100644 src/test/mir-opt/building/custom/simple_assign.rs create mode 100644 src/test/mir-opt/building/custom/simple_assign.simple.built.after.mir create mode 100644 src/test/mir-opt/building/custom/simple_assign.simple_ref.built.after.mir create mode 100644 src/test/ui/feature-gates/feature-gate-custom_mir.rs create mode 100644 src/test/ui/feature-gates/feature-gate-custom_mir.stderr diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs index abfe253d43d..4a4887f1970 100644 --- a/compiler/rustc_borrowck/src/lib.rs +++ b/compiler/rustc_borrowck/src/lib.rs @@ -18,6 +18,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet}; use rustc_data_structures::graph::dominators::Dominators; +use rustc_data_structures::vec_map::VecMap; use rustc_errors::{Diagnostic, DiagnosticBuilder, ErrorGuaranteed}; use rustc_hir as hir; use rustc_hir::def_id::LocalDefId; @@ -129,6 +130,19 @@ fn mir_borrowck<'tcx>( ) -> &'tcx BorrowCheckResult<'tcx> { let (input_body, promoted) = tcx.mir_promoted(def); debug!("run query mir_borrowck: {}", tcx.def_path_str(def.did.to_def_id())); + + if input_body.borrow().should_skip() { + debug!("Skipping borrowck because of injected body"); + // Let's make up a borrowck result! Fun times! + let result = BorrowCheckResult { + concrete_opaque_types: VecMap::new(), + closure_requirements: None, + used_mut_upvars: SmallVec::new(), + tainted_by_errors: None, + }; + return tcx.arena.alloc(result); + } + let hir_owner = tcx.hir().local_def_id_to_hir_id(def.did).owner; let infcx = diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs index 09a747662e2..e94e038f928 100644 --- a/compiler/rustc_feature/src/active.rs +++ b/compiler/rustc_feature/src/active.rs @@ -152,6 +152,8 @@ pub fn set(&self, features: &mut Features, span: Span) { (active, anonymous_lifetime_in_impl_trait, "1.63.0", None, None), /// Allows identifying the `compiler_builtins` crate. (active, compiler_builtins, "1.13.0", None, None), + /// Allows writing custom MIR + (active, custom_mir, "1.65.0", None, None), /// Outputs useful `assert!` messages (active, generic_assert, "1.63.0", None, None), /// Allows using the `rust-intrinsic`'s "ABI". diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs index 4ff3b3f2a38..dc3a7495684 100644 --- a/compiler/rustc_feature/src/builtin_attrs.rs +++ b/compiler/rustc_feature/src/builtin_attrs.rs @@ -810,6 +810,10 @@ pub struct BuiltinAttribute { rustc_attr!(TEST, rustc_polymorphize_error, Normal, template!(Word), WarnFollowing), rustc_attr!(TEST, rustc_def_path, Normal, template!(Word), WarnFollowing), rustc_attr!(TEST, rustc_mir, Normal, template!(List: "arg1, arg2, ..."), DuplicatesOk), + gated!( + custom_mir, Normal, template!(List: r#"dialect = "...", phase = "...""#), + ErrorFollowing, "the `#[custom_mir]` attribute is just used for the Rust test suite", + ), rustc_attr!(TEST, rustc_dump_program_clauses, Normal, template!(Word), WarnFollowing), rustc_attr!(TEST, rustc_dump_env_program_clauses, Normal, template!(Word), WarnFollowing), rustc_attr!(TEST, rustc_object_lifetime_default, Normal, template!(Word), WarnFollowing), diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs index 0a96d23e354..5290d5aae46 100644 --- a/compiler/rustc_middle/src/mir/mod.rs +++ b/compiler/rustc_middle/src/mir/mod.rs @@ -138,6 +138,48 @@ pub fn phase_index(&self) -> usize { } } } + + /// Parses an `MirPhase` from a pair of strings. Panics if this isn't possible for any reason. + pub fn parse(dialect: String, phase: Option) -> Self { + match &*dialect.to_ascii_lowercase() { + "built" => { + assert!(phase.is_none(), "Cannot specify a phase for `Built` MIR"); + MirPhase::Built + } + "analysis" => Self::Analysis(AnalysisPhase::parse(phase)), + "runtime" => Self::Runtime(RuntimePhase::parse(phase)), + _ => panic!("Unknown MIR dialect {}", dialect), + } + } +} + +impl AnalysisPhase { + pub fn parse(phase: Option) -> Self { + let Some(phase) = phase else { + return Self::Initial; + }; + + match &*phase.to_ascii_lowercase() { + "initial" => Self::Initial, + "post_cleanup" | "post-cleanup" | "postcleanup" => Self::PostCleanup, + _ => panic!("Unknown analysis phase {}", phase), + } + } +} + +impl RuntimePhase { + pub fn parse(phase: Option) -> Self { + let Some(phase) = phase else { + return Self::Initial; + }; + + match &*phase.to_ascii_lowercase() { + "initial" => Self::Initial, + "post_cleanup" | "post-cleanup" | "postcleanup" => Self::PostCleanup, + "optimized" => Self::Optimized, + _ => panic!("Unknown runtime phase {}", phase), + } + } } impl Display for MirPhase { @@ -293,6 +335,13 @@ pub struct Body<'tcx> { /// potentially allow things like `[u8; std::mem::size_of::() * 0]` due to this. pub is_polymorphic: bool, + /// The phase at which this MIR should be "injected" into the compilation process. + /// + /// Everything that comes before this `MirPhase` should be skipped. + /// + /// This is only `Some` if the function that this body comes from was annotated with `rustc_custom_mir`. + pub injection_phase: Option, + pub tainted_by_errors: Option, } @@ -339,6 +388,7 @@ pub fn new( span, required_consts: Vec::new(), is_polymorphic: false, + injection_phase: None, tainted_by_errors, }; body.is_polymorphic = body.has_non_region_param(); @@ -366,6 +416,7 @@ pub fn new_cfg_only(basic_blocks: IndexVec>) -> required_consts: Vec::new(), var_debug_info: Vec::new(), is_polymorphic: false, + injection_phase: None, tainted_by_errors: None, }; body.is_polymorphic = body.has_non_region_param(); @@ -508,6 +559,14 @@ pub fn generator_drop(&self) -> Option<&Body<'tcx>> { pub fn generator_kind(&self) -> Option { self.generator.as_ref().map(|generator| generator.generator_kind) } + + #[inline] + pub fn should_skip(&self) -> bool { + let Some(injection_phase) = self.injection_phase else { + return false; + }; + injection_phase > self.phase + } } #[derive(Copy, Clone, PartialEq, Eq, Debug, TyEncodable, TyDecodable, HashStable)] diff --git a/compiler/rustc_mir_build/src/build/custom/mod.rs b/compiler/rustc_mir_build/src/build/custom/mod.rs new file mode 100644 index 00000000000..68d8766c907 --- /dev/null +++ b/compiler/rustc_mir_build/src/build/custom/mod.rs @@ -0,0 +1,155 @@ +//! Provides the implementation of the `custom_mir` attribute. +//! +//! Up until MIR building, this attribute has absolutely no effect. The `mir!` macro is a normal +//! decl macro that expands like any other, and the code goes through parsing, name resolution and +//! type checking like all other code. In MIR building we finally detect whether this attribute is +//! present, and if so we branch off into this module, which implements the attribute by +//! implementing a custom lowering from THIR to MIR. +//! +//! The result of this lowering is returned "normally" from the `mir_built` query, with the only +//! notable difference being that the `injected` field in the body is set. Various components of the +//! MIR pipeline, like borrowck and the pass manager will then consult this field (via +//! `body.should_skip()`) to skip the parts of the MIR pipeline that precede the MIR phase the user +//! specified. +//! +//! This file defines the general framework for the custom parsing. The parsing for all the +//! "top-level" constructs can be found in the `parse` submodule, while the parsing for statements, +//! terminators, and everything below can be found in the `parse::instruction` submodule. +//! + +use rustc_ast::Attribute; +use rustc_data_structures::fx::FxHashMap; +use rustc_hir::def_id::DefId; +use rustc_index::vec::IndexVec; +use rustc_middle::{ + mir::*, + thir::*, + ty::{Ty, TyCtxt}, +}; +use rustc_span::Span; + +mod parse; + +pub(super) fn build_custom_mir<'tcx>( + tcx: TyCtxt<'tcx>, + did: DefId, + thir: &Thir<'tcx>, + expr: ExprId, + params: &IndexVec>, + return_ty: Ty<'tcx>, + return_ty_span: Span, + span: Span, + attr: &Attribute, +) -> Body<'tcx> { + let mut body = Body { + basic_blocks: BasicBlocks::new(IndexVec::new()), + source: MirSource::item(did), + phase: MirPhase::Built, + source_scopes: IndexVec::new(), + generator: None, + local_decls: LocalDecls::new(), + user_type_annotations: IndexVec::new(), + arg_count: params.len(), + spread_arg: None, + var_debug_info: Vec::new(), + span, + required_consts: Vec::new(), + is_polymorphic: false, + tainted_by_errors: None, + injection_phase: None, + pass_count: 1, + }; + + body.local_decls.push(LocalDecl::new(return_ty, return_ty_span)); + body.basic_blocks_mut().push(BasicBlockData::new(None)); + body.source_scopes.push(SourceScopeData { + span, + parent_scope: None, + inlined: None, + inlined_parent_scope: None, + local_data: ClearCrossCrate::Clear, + }); + body.injection_phase = Some(parse_attribute(attr)); + + let mut pctxt = ParseCtxt { + tcx, + thir, + source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE }, + body: &mut body, + local_map: FxHashMap::default(), + block_map: FxHashMap::default(), + }; + + let res = (|| { + pctxt.parse_args(¶ms)?; + pctxt.parse_body(expr) + })(); + if let Err(err) = res { + tcx.sess.diagnostic().span_fatal( + err.span, + format!("Could not parse {}, found: {:?}", err.expected, err.item_description), + ) + } + + body +} + +fn parse_attribute(attr: &Attribute) -> MirPhase { + let meta_items = attr.meta_item_list().unwrap(); + let mut dialect: Option = None; + let mut phase: Option = None; + + for nested in meta_items { + let name = nested.name_or_empty(); + let value = nested.value_str().unwrap().as_str().to_string(); + match name.as_str() { + "dialect" => { + assert!(dialect.is_none()); + dialect = Some(value); + } + "phase" => { + assert!(phase.is_none()); + phase = Some(value); + } + other => { + panic!("Unexpected key {}", other); + } + } + } + + let Some(dialect) = dialect else { + assert!(phase.is_none()); + return MirPhase::Built; + }; + + MirPhase::parse(dialect, phase) +} + +struct ParseCtxt<'tcx, 'body> { + tcx: TyCtxt<'tcx>, + thir: &'body Thir<'tcx>, + source_info: SourceInfo, + + body: &'body mut Body<'tcx>, + local_map: FxHashMap, + block_map: FxHashMap, +} + +struct ParseError { + span: Span, + item_description: String, + expected: String, +} + +impl<'tcx, 'body> ParseCtxt<'tcx, 'body> { + fn expr_error(&self, expr: ExprId, expected: &'static str) -> ParseError { + let expr = &self.thir[expr]; + ParseError { + span: expr.span, + item_description: format!("{:?}", expr.kind), + expected: expected.to_string(), + } + } +} + +type PResult = Result; diff --git a/compiler/rustc_mir_build/src/build/custom/parse.rs b/compiler/rustc_mir_build/src/build/custom/parse.rs new file mode 100644 index 00000000000..52cb0a4826d --- /dev/null +++ b/compiler/rustc_mir_build/src/build/custom/parse.rs @@ -0,0 +1,245 @@ +use rustc_index::vec::IndexVec; +use rustc_middle::{mir::*, thir::*, ty::Ty}; +use rustc_span::Span; + +use super::{PResult, ParseCtxt, ParseError}; + +mod instruction; + +/// Helper macro for parsing custom MIR. +/// +/// Example usage looks something like: +/// ```rust,ignore (incomplete example) +/// parse_by_kind!( +/// self, // : &ParseCtxt +/// expr_id, // what you're matching against +/// "assignment", // the thing you're trying to parse +/// @call("mir_assign", args) => { args[0] }, // match invocations of the `mir_assign` special function +/// ExprKind::Assign { lhs, .. } => { lhs }, // match thir assignment expressions +/// // no need for fallthrough case - reasonable error is automatically generated +/// ) +/// ``` +macro_rules! parse_by_kind { + ( + $self:ident, + $expr_id:expr, + $expected:literal, + $( + @call($name:literal, $args:ident) => $call_expr:expr, + )* + $( + $pat:pat => $expr:expr, + )* + ) => {{ + let expr_id = $self.preparse($expr_id); + let expr = &$self.thir[expr_id]; + match &expr.kind { + $( + ExprKind::Call { ty, fun: _, args: $args, .. } if { + match ty.kind() { + ty::FnDef(did, _) => { + $self.tcx.is_diagnostic_item(rustc_span::Symbol::intern($name), *did) + } + _ => false, + } + } => $call_expr, + )* + $( + $pat => $expr, + )* + #[allow(unreachable_patterns)] + _ => return Err($self.expr_error(expr_id, $expected)) + } + }}; +} +pub(crate) use parse_by_kind; + +impl<'tcx, 'body> ParseCtxt<'tcx, 'body> { + /// Expressions should only ever be matched on after preparsing them. This removes extra scopes + /// we don't care about. + fn preparse(&self, expr_id: ExprId) -> ExprId { + let expr = &self.thir[expr_id]; + match expr.kind { + ExprKind::Scope { value, .. } => self.preparse(value), + _ => expr_id, + } + } + + fn statement_as_expr(&self, stmt_id: StmtId) -> PResult { + match &self.thir[stmt_id].kind { + StmtKind::Expr { expr, .. } => Ok(*expr), + kind @ StmtKind::Let { pattern, .. } => { + return Err(ParseError { + span: pattern.span, + item_description: format!("{:?}", kind), + expected: "expression".to_string(), + }); + } + } + } + + pub fn parse_args(&mut self, params: &IndexVec>) -> PResult<()> { + for param in params.iter() { + let (var, span) = { + let pat = param.pat.as_ref().unwrap(); + match &pat.kind { + PatKind::Binding { var, .. } => (*var, pat.span), + _ => { + return Err(ParseError { + span: pat.span, + item_description: format!("{:?}", pat.kind), + expected: "local".to_string(), + }); + } + } + }; + let decl = LocalDecl::new(param.ty, span); + let local = self.body.local_decls.push(decl); + self.local_map.insert(var, local); + } + + Ok(()) + } + + /// Bodies are of the form: + /// + /// ```text + /// { + /// let bb1: BasicBlock; + /// let bb2: BasicBlock; + /// { + /// let RET: _; + /// let local1; + /// let local2; + /// + /// { + /// { // entry block + /// statement1; + /// terminator1 + /// }; + /// + /// bb1 = { + /// statement2; + /// terminator2 + /// }; + /// + /// bb2 = { + /// statement3; + /// terminator3 + /// } + /// + /// RET + /// } + /// } + /// } + /// ``` + /// + /// This allows us to easily parse the basic blocks declarations, local declarations, and + /// basic block definitions in order. + pub fn parse_body(&mut self, expr_id: ExprId) -> PResult<()> { + let body = parse_by_kind!(self, expr_id, "whole body", + ExprKind::Block { block } => self.thir[*block].expr.unwrap(), + ); + let (block_decls, rest) = parse_by_kind!(self, body, "body with block decls", + ExprKind::Block { block } => { + let block = &self.thir[*block]; + (&block.stmts, block.expr.unwrap()) + }, + ); + self.parse_block_decls(block_decls.iter().copied())?; + + let (local_decls, rest) = parse_by_kind!(self, rest, "body with local decls", + ExprKind::Block { block } => { + let block = &self.thir[*block]; + (&block.stmts, block.expr.unwrap()) + }, + ); + self.parse_local_decls(local_decls.iter().copied())?; + + let block_defs = parse_by_kind!(self, rest, "body with block defs", + ExprKind::Block { block } => &self.thir[*block].stmts, + ); + for (i, block_def) in block_defs.iter().enumerate() { + let block = self.parse_block_def(self.statement_as_expr(*block_def)?)?; + self.body.basic_blocks_mut()[BasicBlock::from_usize(i)] = block; + } + + Ok(()) + } + + fn parse_block_decls(&mut self, stmts: impl Iterator) -> PResult<()> { + for stmt in stmts { + let (var, _, _) = self.parse_let_statement(stmt)?; + let data = BasicBlockData::new(None); + let block = self.body.basic_blocks_mut().push(data); + self.block_map.insert(var, block); + } + + Ok(()) + } + + fn parse_local_decls(&mut self, mut stmts: impl Iterator) -> PResult<()> { + let (ret_var, ..) = self.parse_let_statement(stmts.next().unwrap())?; + self.local_map.insert(ret_var, Local::from_u32(0)); + + for stmt in stmts { + let (var, ty, span) = self.parse_let_statement(stmt)?; + let decl = LocalDecl::new(ty, span); + let local = self.body.local_decls.push(decl); + self.local_map.insert(var, local); + } + + Ok(()) + } + + fn parse_let_statement(&mut self, stmt_id: StmtId) -> PResult<(LocalVarId, Ty<'tcx>, Span)> { + let pattern = match &self.thir[stmt_id].kind { + StmtKind::Let { pattern, .. } => pattern, + StmtKind::Expr { expr, .. } => { + return Err(self.expr_error(*expr, "let statement")); + } + }; + + self.parse_var(pattern) + } + + fn parse_var(&mut self, mut pat: &Pat<'tcx>) -> PResult<(LocalVarId, Ty<'tcx>, Span)> { + // Make sure we throw out any `AscribeUserType` we find + loop { + match &pat.kind { + PatKind::Binding { var, ty, .. } => break Ok((*var, *ty, pat.span)), + PatKind::AscribeUserType { subpattern, .. } => { + pat = subpattern; + } + _ => { + break Err(ParseError { + span: pat.span, + item_description: format!("{:?}", pat.kind), + expected: "local".to_string(), + }); + } + } + } + } + + fn parse_block_def(&self, expr_id: ExprId) -> PResult> { + let block = parse_by_kind!(self, expr_id, "basic block", + ExprKind::Block { block } => &self.thir[*block], + ); + + let mut data = BasicBlockData::new(None); + for stmt_id in &*block.stmts { + let stmt = self.statement_as_expr(*stmt_id)?; + let statement = self.parse_statement(stmt)?; + data.statements.push(Statement { source_info: self.source_info, kind: statement }); + } + + let Some(trailing) = block.expr else { + return Err(self.expr_error(expr_id, "terminator")) + }; + let terminator = self.parse_terminator(trailing)?; + data.terminator = Some(Terminator { source_info: self.source_info, kind: terminator }); + + Ok(data) + } +} diff --git a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs new file mode 100644 index 00000000000..6d6176584f5 --- /dev/null +++ b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs @@ -0,0 +1,72 @@ +use rustc_middle::{mir::*, thir::*, ty}; + +use super::{parse_by_kind, PResult, ParseCtxt}; + +impl<'tcx, 'body> ParseCtxt<'tcx, 'body> { + pub fn parse_statement(&self, expr_id: ExprId) -> PResult> { + parse_by_kind!(self, expr_id, "statement", + @call("mir_retag", args) => { + Ok(StatementKind::Retag(RetagKind::Default, Box::new(self.parse_place(args[0])?))) + }, + @call("mir_retag_raw", args) => { + Ok(StatementKind::Retag(RetagKind::Raw, Box::new(self.parse_place(args[0])?))) + }, + ExprKind::Assign { lhs, rhs } => { + let lhs = self.parse_place(*lhs)?; + let rhs = self.parse_rvalue(*rhs)?; + Ok(StatementKind::Assign(Box::new((lhs, rhs)))) + }, + ) + } + + pub fn parse_terminator(&self, expr_id: ExprId) -> PResult> { + parse_by_kind!(self, expr_id, "terminator", + @call("mir_return", _args) => { + Ok(TerminatorKind::Return) + }, + @call("mir_goto", args) => { + Ok(TerminatorKind::Goto { target: self.parse_block(args[0])? } ) + }, + ) + } + + fn parse_rvalue(&self, expr_id: ExprId) -> PResult> { + parse_by_kind!(self, expr_id, "rvalue", + ExprKind::Borrow { borrow_kind, arg } => Ok( + Rvalue::Ref(self.tcx.lifetimes.re_erased, *borrow_kind, self.parse_place(*arg)?) + ), + ExprKind::AddressOf { mutability, arg } => Ok( + Rvalue::AddressOf(*mutability, self.parse_place(*arg)?) + ), + _ => self.parse_operand(expr_id).map(Rvalue::Use), + ) + } + + fn parse_operand(&self, expr_id: ExprId) -> PResult> { + parse_by_kind!(self, expr_id, "operand", + @call("mir_move", args) => self.parse_place(args[0]).map(Operand::Move), + _ => self.parse_place(expr_id).map(Operand::Copy), + ) + } + + fn parse_place(&self, expr_id: ExprId) -> PResult> { + parse_by_kind!(self, expr_id, "place", + ExprKind::Deref { arg } => Ok( + self.parse_place(*arg)?.project_deeper(&[PlaceElem::Deref], self.tcx) + ), + _ => self.parse_local(expr_id).map(Place::from), + ) + } + + fn parse_local(&self, expr_id: ExprId) -> PResult { + parse_by_kind!(self, expr_id, "local", + ExprKind::VarRef { id } => Ok(self.local_map[id]), + ) + } + + fn parse_block(&self, expr_id: ExprId) -> PResult { + parse_by_kind!(self, expr_id, "basic block", + ExprKind::VarRef { id } => Ok(self.block_map[id]), + ) + } +} diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs index cbcf9cd129f..437ac8d82a1 100644 --- a/compiler/rustc_mir_build/src/build/mod.rs +++ b/compiler/rustc_mir_build/src/build/mod.rs @@ -481,6 +481,22 @@ fn construct_fn<'tcx>( (None, fn_sig.output()) }; + if let Some(custom_mir_attr) = + tcx.hir().attrs(fn_id).iter().find(|attr| attr.name_or_empty() == sym::custom_mir) + { + return custom::build_custom_mir( + tcx, + fn_def.did.to_def_id(), + thir, + expr, + arguments, + return_ty, + return_ty_span, + span, + custom_mir_attr, + ); + } + let infcx = tcx.infer_ctxt().build(); let mut builder = Builder::new( thir, @@ -1033,6 +1049,7 @@ pub(crate) fn parse_float_into_scalar( mod block; mod cfg; +mod custom; mod expr; mod matches; mod misc; diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs index c7a7c3e3fa8..c4639d3a513 100644 --- a/compiler/rustc_mir_build/src/thir/cx/expr.rs +++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs @@ -51,11 +51,17 @@ pub(super) fn mirror_expr_inner(&mut self, hir_expr: &'tcx hir::Expr<'tcx>) -> E trace!(?expr.ty); // Now apply adjustments, if any. - for adjustment in self.typeck_results.expr_adjustments(hir_expr) { - trace!(?expr, ?adjustment); - let span = expr.span; - expr = - self.apply_adjustment(hir_expr, expr, adjustment, adjustment_span.unwrap_or(span)); + if self.apply_adjustments { + for adjustment in self.typeck_results.expr_adjustments(hir_expr) { + trace!(?expr, ?adjustment); + let span = expr.span; + expr = self.apply_adjustment( + hir_expr, + expr, + adjustment, + adjustment_span.unwrap_or(span), + ); + } } trace!(?expr.ty, "after adjustments"); diff --git a/compiler/rustc_mir_build/src/thir/cx/mod.rs b/compiler/rustc_mir_build/src/thir/cx/mod.rs index 1d95d6b53fb..b5c4b7b137d 100644 --- a/compiler/rustc_mir_build/src/thir/cx/mod.rs +++ b/compiler/rustc_mir_build/src/thir/cx/mod.rs @@ -80,6 +80,9 @@ struct Cx<'tcx> { /// for the receiver. adjustment_span: Option<(HirId, Span)>, + /// False to indicate that adjustments should not be applied. Only used for `custom_mir` + apply_adjustments: bool, + /// The `DefId` of the owner of this body. body_owner: DefId, } @@ -87,6 +90,8 @@ struct Cx<'tcx> { impl<'tcx> Cx<'tcx> { fn new(tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam) -> Cx<'tcx> { let typeck_results = tcx.typeck_opt_const_arg(def); + let did = def.did; + let hir = tcx.hir(); Cx { tcx, thir: Thir::new(), @@ -94,8 +99,12 @@ fn new(tcx: TyCtxt<'tcx>, def: ty::WithOptConstParam) -> Cx<'tcx> { region_scope_tree: tcx.region_scope_tree(def.did), typeck_results, rvalue_scopes: &typeck_results.rvalue_scopes, - body_owner: def.did.to_def_id(), + body_owner: did.to_def_id(), adjustment_span: None, + apply_adjustments: hir + .attrs(hir.local_def_id_to_hir_id(did)) + .iter() + .all(|attr| attr.name_or_empty() != rustc_span::sym::custom_mir), } } diff --git a/compiler/rustc_mir_transform/src/check_unsafety.rs b/compiler/rustc_mir_transform/src/check_unsafety.rs index 269d9f3b102..e783d189137 100644 --- a/compiler/rustc_mir_transform/src/check_unsafety.rs +++ b/compiler/rustc_mir_transform/src/check_unsafety.rs @@ -471,6 +471,14 @@ fn unsafety_check_result<'tcx>( // `mir_built` force this. let body = &tcx.mir_built(def).borrow(); + if body.should_skip() { + return tcx.arena.alloc(UnsafetyCheckResult { + violations: Vec::new(), + used_unsafe_blocks: FxHashSet::default(), + unused_unsafes: Some(Vec::new()), + }); + } + let param_env = tcx.param_env(def.did); let mut checker = UnsafetyChecker::new(body, def.did, tcx, param_env); diff --git a/compiler/rustc_mir_transform/src/pass_manager.rs b/compiler/rustc_mir_transform/src/pass_manager.rs index 230c6a7cb4b..27dbc3e22c9 100644 --- a/compiler/rustc_mir_transform/src/pass_manager.rs +++ b/compiler/rustc_mir_transform/src/pass_manager.rs @@ -96,45 +96,48 @@ fn run_passes_inner<'tcx>( phase_change: Option, validate_each: bool, ) { - let validate = validate_each & tcx.sess.opts.unstable_opts.validate_mir; + let validate = validate_each & tcx.sess.opts.unstable_opts.validate_mir & !body.should_skip(); let overridden_passes = &tcx.sess.opts.unstable_opts.mir_enable_passes; trace!(?overridden_passes); - for pass in passes { - let name = pass.name(); + if !body.should_skip() { + for pass in passes { + let name = pass.name(); - let overridden = - overridden_passes.iter().rev().find(|(s, _)| s == &*name).map(|(_name, polarity)| { - trace!( - pass = %name, - "{} as requested by flag", - if *polarity { "Running" } else { "Not running" }, - ); - *polarity - }); - if !overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess)) { - continue; + let overridden = overridden_passes.iter().rev().find(|(s, _)| s == &*name).map( + |(_name, polarity)| { + trace!( + pass = %name, + "{} as requested by flag", + if *polarity { "Running" } else { "Not running" }, + ); + *polarity + }, + ); + if !overridden.unwrap_or_else(|| pass.is_enabled(&tcx.sess)) { + continue; + } + + let dump_enabled = pass.is_mir_dump_enabled(); + + if dump_enabled { + dump_mir_for_pass(tcx, body, &name, false); + } + if validate { + validate_body(tcx, body, format!("before pass {}", name)); + } + + pass.run_pass(tcx, body); + + if dump_enabled { + dump_mir_for_pass(tcx, body, &name, true); + } + if validate { + validate_body(tcx, body, format!("after pass {}", name)); + } + + body.pass_count += 1; } - - let dump_enabled = pass.is_mir_dump_enabled(); - - if dump_enabled { - dump_mir_for_pass(tcx, body, &name, false); - } - if validate { - validate_body(tcx, body, format!("before pass {}", name)); - } - - pass.run_pass(tcx, body); - - if dump_enabled { - dump_mir_for_pass(tcx, body, &name, true); - } - if validate { - validate_body(tcx, body, format!("after pass {}", name)); - } - - body.pass_count += 1; } if let Some(new_phase) = phase_change { diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index cccc4897ecc..54a61483a11 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -584,6 +584,7 @@ custom_attribute, custom_derive, custom_inner_attributes, + custom_mir, custom_test_frameworks, d, d32, diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs index bfbd4301230..cec603dcb10 100644 --- a/library/core/src/intrinsics.rs +++ b/library/core/src/intrinsics.rs @@ -59,6 +59,9 @@ use crate::marker::Tuple; use crate::mem; +#[cfg(not(bootstrap))] +pub mod mir; + // These imports are used for simplifying intra-doc links #[allow(unused_imports)] #[cfg(all(target_has_atomic = "8", target_has_atomic = "32", target_has_atomic = "ptr"))] diff --git a/library/core/src/intrinsics/mir.rs b/library/core/src/intrinsics/mir.rs new file mode 100644 index 00000000000..1bacdc39148 --- /dev/null +++ b/library/core/src/intrinsics/mir.rs @@ -0,0 +1,123 @@ +//! Rustc internal tooling for hand-writing MIR. +//! +//! If for some reasons you are not writing rustc tests and have found yourself considering using +//! this feature, turn back. This is *exceptionally* unstable. There is no attempt at all to make +//! anything work besides those things which the rustc test suite happened to need. If you make a +//! typo you'll probably ICE. Really, this is not the solution to your problems. Consider instead +//! supporting the [stable MIR project group](https://github.com/rust-lang/project-stable-mir). +//! +//! The documentation for this module describes how to use this feature. If you are interested in +//! hacking on the implementation, most of that documentation lives at +//! `rustc_mir_building/src/build/custom/mod.rs`. +//! +//! Typical usage will look like this: +//! +//! ```rust +//! #![feature(core_intrinsics, custom_mir)] +//! +//! extern crate core; +//! use core::intrinsics::mir::*; +//! +//! #[custom_mir(dialect = "built")] +//! pub fn simple(x: i32) -> i32 { +//! mir!( +//! let temp1: i32; +//! let temp2: _; +//! +//! { +//! temp1 = x; +//! Goto(exit) +//! } +//! +//! exit = { +//! temp2 = Move(temp1); +//! RET = temp2; +//! Return() +//! } +//! ) +//! } +//! ``` +//! +//! Hopefully most of this is fairly self-explanatory. Expanding on some notable details: +//! +//! - The `custom_mir` attribute tells the compiler to treat the function as being custom MIR. This +//! attribute only works on functions - there is no way to insert custom MIR into the middle of +//! another function. +//! - The `dialect` and `phase` parameters indicate which version of MIR you are inserting here. +//! This will normally be the phase that corresponds to the thing you are trying to test. The +//! phase can be omitted for dialects that have just one. +//! - You should define your function signature like you normally would. Externally, this function +//! can be called like any other function. +//! - Type inference works - you don't have to spell out the type of all of your locals. +//! +//! For now, all statements and terminators are parsed from nested invocations of the special +//! functions provided in this module. We additionally want to (but do not yet) support more +//! "normal" Rust syntax in places where it makes sense. Also, most kinds of instructions are not +//! supported yet. +//! + +#![unstable( + feature = "custom_mir", + reason = "MIR is an implementation detail and extremely unstable", + issue = "none" +)] +#![allow(unused_variables, non_snake_case, missing_debug_implementations)] + +/// Type representing basic blocks. +/// +/// All terminators will have this type as a return type. It helps achieve some type safety. +pub struct BasicBlock; + +macro_rules! define { + ($name:literal, $($sig:tt)*) => { + #[rustc_diagnostic_item = $name] + pub $($sig)* { panic!() } + } +} + +define!("mir_return", fn Return() -> BasicBlock); +define!("mir_goto", fn Goto(destination: BasicBlock) -> BasicBlock); +define!("mir_retag", fn Retag(place: T)); +define!("mir_retag_raw", fn RetagRaw(place: T)); +define!("mir_move", fn Move(place: T) -> T); + +/// Convenience macro for generating custom MIR. +/// +/// See the module documentation for syntax details. This macro is not magic - it only transforms +/// your MIR into something that is easier to parse in the compiler. +#[rustc_macro_transparency = "transparent"] +pub macro mir { + ( + $(let $local_decl:ident $(: $local_decl_ty:ty)? ;)* + + $entry_block:block + + $( + $block_name:ident = $block:block + )* + ) => {{ + // First, we declare all basic blocks. + $( + let $block_name: ::core::intrinsics::mir::BasicBlock; + )* + + { + // Now all locals + #[allow(non_snake_case)] + let RET; + $( + let $local_decl $(: $local_decl_ty)? ; + )* + + { + // Finally, the contents of the basic blocks + $entry_block; + $( + $block; + )* + + RET + } + } + }} +} diff --git a/src/test/mir-opt/building/custom/references.immut_ref.built.after.mir b/src/test/mir-opt/building/custom/references.immut_ref.built.after.mir new file mode 100644 index 00000000000..4a5ddde4081 --- /dev/null +++ b/src/test/mir-opt/building/custom/references.immut_ref.built.after.mir @@ -0,0 +1,14 @@ +// MIR for `immut_ref` after built + +fn immut_ref(_1: &i32) -> &i32 { + let mut _0: &i32; // return place in scope 0 at $DIR/references.rs:+0:30: +0:34 + let mut _2: *const i32; // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL + + bb0: { + _2 = &raw const (*_1); // scope 0 at $DIR/references.rs:+0:1: +0:34 + Retag([raw] _2); // scope 0 at $DIR/references.rs:+0:1: +0:34 + _0 = &(*_2); // scope 0 at $DIR/references.rs:+0:1: +0:34 + Retag(_0); // scope 0 at $DIR/references.rs:+0:1: +0:34 + return; // scope 0 at $DIR/references.rs:+0:1: +0:34 + } +} diff --git a/src/test/mir-opt/building/custom/references.mut_ref.built.after.mir b/src/test/mir-opt/building/custom/references.mut_ref.built.after.mir new file mode 100644 index 00000000000..ec8509f69d1 --- /dev/null +++ b/src/test/mir-opt/building/custom/references.mut_ref.built.after.mir @@ -0,0 +1,14 @@ +// MIR for `mut_ref` after built + +fn mut_ref(_1: &mut i32) -> &mut i32 { + let mut _0: &mut i32; // return place in scope 0 at $DIR/references.rs:+0:32: +0:40 + let mut _2: *mut i32; // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL + + bb0: { + _2 = &raw mut (*_1); // scope 0 at $DIR/references.rs:+0:1: +0:40 + Retag([raw] _2); // scope 0 at $DIR/references.rs:+0:1: +0:40 + _0 = &mut (*_2); // scope 0 at $DIR/references.rs:+0:1: +0:40 + Retag(_0); // scope 0 at $DIR/references.rs:+0:1: +0:40 + return; // scope 0 at $DIR/references.rs:+0:1: +0:40 + } +} diff --git a/src/test/mir-opt/building/custom/references.rs b/src/test/mir-opt/building/custom/references.rs new file mode 100644 index 00000000000..dee85722e86 --- /dev/null +++ b/src/test/mir-opt/building/custom/references.rs @@ -0,0 +1,43 @@ +#![feature(custom_mir, core_intrinsics)] + +extern crate core; +use core::intrinsics::mir::*; +use core::ptr::{addr_of, addr_of_mut}; + +// EMIT_MIR references.mut_ref.built.after.mir +#[custom_mir(dialect = "runtime", phase = "optimized")] +pub fn mut_ref(x: &mut i32) -> &mut i32 { + mir!( + let t: *mut i32; + + { + t = addr_of_mut!(*x); + RetagRaw(t); + RET = &mut *t; + Retag(RET); + Return() + } + ) +} + +// EMIT_MIR references.immut_ref.built.after.mir +#[custom_mir(dialect = "runtime", phase = "optimized")] +pub fn immut_ref(x: &i32) -> &i32 { + mir!( + let t: *const i32; + + { + t = addr_of!(*x); + RetagRaw(t); + RET = & *t; + Retag(RET); + Return() + } + ) +} + +fn main() { + let mut x = 5; + assert_eq!(*mut_ref(&mut x), 5); + assert_eq!(*immut_ref(&x), 5); +} diff --git a/src/test/mir-opt/building/custom/simple_assign.rs b/src/test/mir-opt/building/custom/simple_assign.rs new file mode 100644 index 00000000000..ec6dbe1d052 --- /dev/null +++ b/src/test/mir-opt/building/custom/simple_assign.rs @@ -0,0 +1,37 @@ +#![feature(custom_mir, core_intrinsics)] + +extern crate core; +use core::intrinsics::mir::*; + +// EMIT_MIR simple_assign.simple.built.after.mir +#[custom_mir(dialect = "built")] +pub fn simple(x: i32) -> i32 { + mir!( + let temp1: i32; + let temp2: _; + + { + temp1 = x; + Goto(exit) + } + + exit = { + temp2 = Move(temp1); + RET = temp2; + Return() + } + ) +} + +// EMIT_MIR simple_assign.simple_ref.built.after.mir +#[custom_mir(dialect = "built")] +pub fn simple_ref(x: &mut i32) -> &mut i32 { + mir!({ + RET = Move(x); + Return() + }) +} + +fn main() { + assert_eq!(5, simple(5)); +} diff --git a/src/test/mir-opt/building/custom/simple_assign.simple.built.after.mir b/src/test/mir-opt/building/custom/simple_assign.simple.built.after.mir new file mode 100644 index 00000000000..a5a2834c2e1 --- /dev/null +++ b/src/test/mir-opt/building/custom/simple_assign.simple.built.after.mir @@ -0,0 +1,18 @@ +// MIR for `simple` after built + +fn simple(_1: i32) -> i32 { + let mut _0: i32; // return place in scope 0 at $DIR/simple_assign.rs:+0:26: +0:29 + let mut _2: i32; // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL + let mut _3: i32; // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL + + bb0: { + _2 = _1; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:29 + goto -> bb1; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:29 + } + + bb1: { + _3 = move _2; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:29 + _0 = _3; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:29 + return; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:29 + } +} diff --git a/src/test/mir-opt/building/custom/simple_assign.simple_ref.built.after.mir b/src/test/mir-opt/building/custom/simple_assign.simple_ref.built.after.mir new file mode 100644 index 00000000000..6c90f0130a2 --- /dev/null +++ b/src/test/mir-opt/building/custom/simple_assign.simple_ref.built.after.mir @@ -0,0 +1,10 @@ +// MIR for `simple_ref` after built + +fn simple_ref(_1: &mut i32) -> &mut i32 { + let mut _0: &mut i32; // return place in scope 0 at $DIR/simple_assign.rs:+0:35: +0:43 + + bb0: { + _0 = move _1; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:43 + return; // scope 0 at $DIR/simple_assign.rs:+0:1: +0:43 + } +} diff --git a/src/test/ui/feature-gates/feature-gate-custom_mir.rs b/src/test/ui/feature-gates/feature-gate-custom_mir.rs new file mode 100644 index 00000000000..0126dde2f7d --- /dev/null +++ b/src/test/ui/feature-gates/feature-gate-custom_mir.rs @@ -0,0 +1,12 @@ +#![feature(core_intrinsics)] + +extern crate core; + +#[custom_mir(dialect = "built")] //~ ERROR the `#[custom_mir]` attribute is just used for the Rust test suite +pub fn foo(_x: i32) -> i32 { + 0 +} + +fn main() { + assert_eq!(2, foo(2)); +} diff --git a/src/test/ui/feature-gates/feature-gate-custom_mir.stderr b/src/test/ui/feature-gates/feature-gate-custom_mir.stderr new file mode 100644 index 00000000000..3c149d30d82 --- /dev/null +++ b/src/test/ui/feature-gates/feature-gate-custom_mir.stderr @@ -0,0 +1,11 @@ +error[E0658]: the `#[custom_mir]` attribute is just used for the Rust test suite + --> $DIR/feature-gate-custom_mir.rs:5:1 + | +LL | #[custom_mir(dialect = "built")] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: add `#![feature(custom_mir)]` to the crate attributes to enable + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0658`.