diff options
Diffstat (limited to 'compiler/rustc_mir_build/src/build/scope.rs')
| -rw-r--r-- | compiler/rustc_mir_build/src/build/scope.rs | 64 |
1 files changed, 44 insertions, 20 deletions
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs index 3cebd5ebe..33f49ffda 100644 --- a/compiler/rustc_mir_build/src/build/scope.rs +++ b/compiler/rustc_mir_build/src/build/scope.rs @@ -85,6 +85,7 @@ use std::mem; use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder, CFG}; use rustc_data_structures::fx::FxHashMap; +use rustc_hir::HirId; use rustc_index::vec::IndexVec; use rustc_middle::middle::region; use rustc_middle::mir::*; @@ -443,8 +444,9 @@ impl<'tcx> Scopes<'tcx> { impl<'a, 'tcx> Builder<'a, 'tcx> { // Adding and removing scopes // ========================== - // Start a breakable scope, which tracks where `continue`, `break` and - // `return` should branch to. + + /// Start a breakable scope, which tracks where `continue`, `break` and + /// `return` should branch to. pub(crate) fn in_breakable_scope<F>( &mut self, loop_block: Option<BasicBlock>, @@ -566,25 +568,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { F: FnOnce(&mut Builder<'a, 'tcx>) -> BlockAnd<R>, { let source_scope = self.source_scope; - let tcx = self.tcx; if let LintLevel::Explicit(current_hir_id) = lint_level { - // Use `maybe_lint_level_root_bounded` with `root_lint_level` as a bound - // to avoid adding Hir dependencies on our parents. - // We estimate the true lint roots here to avoid creating a lot of source scopes. - - let parent_root = tcx.maybe_lint_level_root_bounded( - self.source_scopes[source_scope].local_data.as_ref().assert_crate_local().lint_root, - self.hir_id, - ); - let current_root = tcx.maybe_lint_level_root_bounded(current_hir_id, self.hir_id); - - if parent_root != current_root { - self.source_scope = self.new_source_scope( - region_scope.1.span, - LintLevel::Explicit(current_root), - None, - ); - } + let parent_id = + self.source_scopes[source_scope].local_data.as_ref().assert_crate_local().lint_root; + self.maybe_new_source_scope(region_scope.1.span, None, current_hir_id, parent_id); } self.push_scope(region_scope); let mut block; @@ -757,6 +744,40 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { )) } + /// Possibly creates a new source scope if `current_root` and `parent_root` + /// are different, or if -Zmaximal-hir-to-mir-coverage is enabled. + pub(crate) fn maybe_new_source_scope( + &mut self, + span: Span, + safety: Option<Safety>, + current_id: HirId, + parent_id: HirId, + ) { + let (current_root, parent_root) = + if self.tcx.sess.opts.unstable_opts.maximal_hir_to_mir_coverage { + // Some consumers of rustc need to map MIR locations back to HIR nodes. Currently the + // the only part of rustc that tracks MIR -> HIR is the `SourceScopeLocalData::lint_root` + // field that tracks lint levels for MIR locations. Normally the number of source scopes + // is limited to the set of nodes with lint annotations. The -Zmaximal-hir-to-mir-coverage + // flag changes this behavior to maximize the number of source scopes, increasing the + // granularity of the MIR->HIR mapping. + (current_id, parent_id) + } else { + // Use `maybe_lint_level_root_bounded` with `self.hir_id` as a bound + // to avoid adding Hir dependencies on our parents. + // We estimate the true lint roots here to avoid creating a lot of source scopes. + ( + self.tcx.maybe_lint_level_root_bounded(current_id, self.hir_id), + self.tcx.maybe_lint_level_root_bounded(parent_id, self.hir_id), + ) + }; + + if current_root != parent_root { + let lint_level = LintLevel::Explicit(current_root); + self.source_scope = self.new_source_scope(span, lint_level, safety); + } + } + /// Creates a new source scope, nested in the current one. pub(crate) fn new_source_scope( &mut self, @@ -799,6 +820,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // Finding scopes // ============== + /// Returns the scope that we should use as the lifetime of an /// operand. Basically, an operand must live until it is consumed. /// This is similar to, but not quite the same as, the temporary @@ -824,6 +846,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // Scheduling drops // ================ + pub(crate) fn schedule_drop_storage_and_value( &mut self, span: Span, @@ -996,6 +1019,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // Other // ===== + /// Returns the [DropIdx] for the innermost drop if the function unwound at /// this point. The `DropIdx` will be created if it doesn't already exist. fn diverge_cleanup(&mut self) -> DropIdx { |