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| 1 | +use std::collections::hash_map::Entry; |
| 2 | + |
| 3 | +use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext}; |
| 4 | +use rustc_codegen_ssa::traits::*; |
| 5 | +use rustc_data_structures::fx::FxHashMap; |
| 6 | +use rustc_index::bit_set::DenseBitSet; |
| 7 | +use rustc_middle::mir::{Body, SourceScope}; |
| 8 | +use rustc_middle::ty::layout::{FnAbiOf, HasTypingEnv}; |
| 9 | +use rustc_middle::ty::{self, Instance}; |
| 10 | +use rustc_session::config::DebugInfo; |
| 11 | +use rustc_span::{BytePos, DUMMY_SP, hygiene}; |
| 12 | + |
| 13 | +use super::metadata::file_metadata; |
| 14 | +use super::utils::DIB; |
| 15 | +use crate::common::CodegenCx; |
| 16 | +use crate::llvm; |
| 17 | +use crate::llvm::debuginfo::{DILocation, DIScope}; |
| 18 | + |
| 19 | +/// Produces DIScope DIEs for each MIR Scope which has variables defined in it. |
| 20 | +// FIXME(eddyb) almost all of this should be in `rustc_codegen_ssa::mir::debuginfo`. |
| 21 | +pub(crate) fn compute_mir_scopes<'ll, 'tcx>( |
| 22 | + cx: &CodegenCx<'ll, 'tcx>, |
| 23 | + instance: Instance<'tcx>, |
| 24 | + mir: &Body<'tcx>, |
| 25 | + debug_context: &mut FunctionDebugContext<'tcx, &'ll DIScope, &'ll DILocation>, |
| 26 | +) { |
| 27 | + // Find all scopes with variables defined in them. |
| 28 | + let variables = if cx.sess().opts.debuginfo == DebugInfo::Full { |
| 29 | + let mut vars = DenseBitSet::new_empty(mir.source_scopes.len()); |
| 30 | + // FIXME(eddyb) take into account that arguments always have debuginfo, |
| 31 | + // irrespective of their name (assuming full debuginfo is enabled). |
| 32 | + // NOTE(eddyb) actually, on second thought, those are always in the |
| 33 | + // function scope, which always exists. |
| 34 | + for var_debug_info in &mir.var_debug_info { |
| 35 | + vars.insert(var_debug_info.source_info.scope); |
| 36 | + } |
| 37 | + Some(vars) |
| 38 | + } else { |
| 39 | + // Nothing to emit, of course. |
| 40 | + None |
| 41 | + }; |
| 42 | + let mut instantiated = DenseBitSet::new_empty(mir.source_scopes.len()); |
| 43 | + let mut discriminators = FxHashMap::default(); |
| 44 | + // Instantiate all scopes. |
| 45 | + for scope in mir.source_scopes.indices() { |
| 46 | + make_mir_scope( |
| 47 | + cx, |
| 48 | + instance, |
| 49 | + mir, |
| 50 | + &variables, |
| 51 | + debug_context, |
| 52 | + &mut instantiated, |
| 53 | + &mut discriminators, |
| 54 | + scope, |
| 55 | + ); |
| 56 | + } |
| 57 | + assert!(instantiated.count() == mir.source_scopes.len()); |
| 58 | +} |
| 59 | + |
| 60 | +fn make_mir_scope<'ll, 'tcx>( |
| 61 | + cx: &CodegenCx<'ll, 'tcx>, |
| 62 | + instance: Instance<'tcx>, |
| 63 | + mir: &Body<'tcx>, |
| 64 | + variables: &Option<DenseBitSet<SourceScope>>, |
| 65 | + debug_context: &mut FunctionDebugContext<'tcx, &'ll DIScope, &'ll DILocation>, |
| 66 | + instantiated: &mut DenseBitSet<SourceScope>, |
| 67 | + discriminators: &mut FxHashMap<BytePos, u32>, |
| 68 | + scope: SourceScope, |
| 69 | +) { |
| 70 | + if instantiated.contains(scope) { |
| 71 | + return; |
| 72 | + } |
| 73 | + |
| 74 | + let scope_data = &mir.source_scopes[scope]; |
| 75 | + let parent_scope = if let Some(parent) = scope_data.parent_scope { |
| 76 | + make_mir_scope( |
| 77 | + cx, |
| 78 | + instance, |
| 79 | + mir, |
| 80 | + variables, |
| 81 | + debug_context, |
| 82 | + instantiated, |
| 83 | + discriminators, |
| 84 | + parent, |
| 85 | + ); |
| 86 | + debug_context.scopes[parent] |
| 87 | + } else { |
| 88 | + // The root is the function itself. |
| 89 | + let file = cx.sess().source_map().lookup_source_file(mir.span.lo()); |
| 90 | + debug_context.scopes[scope] = DebugScope { |
| 91 | + file_start_pos: file.start_pos, |
| 92 | + file_end_pos: file.end_position(), |
| 93 | + ..debug_context.scopes[scope] |
| 94 | + }; |
| 95 | + instantiated.insert(scope); |
| 96 | + return; |
| 97 | + }; |
| 98 | + |
| 99 | + if let Some(vars) = variables |
| 100 | + && !vars.contains(scope) |
| 101 | + && scope_data.inlined.is_none() |
| 102 | + { |
| 103 | + // Do not create a DIScope if there are no variables defined in this |
| 104 | + // MIR `SourceScope`, and it's not `inlined`, to avoid debuginfo bloat. |
| 105 | + debug_context.scopes[scope] = parent_scope; |
| 106 | + instantiated.insert(scope); |
| 107 | + return; |
| 108 | + } |
| 109 | + |
| 110 | + let loc = cx.lookup_debug_loc(scope_data.span.lo()); |
| 111 | + let file_metadata = file_metadata(cx, &loc.file); |
| 112 | + |
| 113 | + let dbg_scope = match scope_data.inlined { |
| 114 | + Some((callee, _)) => { |
| 115 | + // FIXME(eddyb) this would be `self.monomorphize(&callee)` |
| 116 | + // if this is moved to `rustc_codegen_ssa::mir::debuginfo`. |
| 117 | + let callee = cx.tcx.instantiate_and_normalize_erasing_regions( |
| 118 | + instance.args, |
| 119 | + cx.typing_env(), |
| 120 | + ty::EarlyBinder::bind(cx.tcx, callee), |
| 121 | + ); |
| 122 | + debug_context.inlined_function_scopes.entry(callee).or_insert_with(|| { |
| 123 | + let callee_fn_abi = cx.fn_abi_of_instance(callee, ty::List::empty()); |
| 124 | + cx.dbg_scope_fn(callee, callee_fn_abi, None) |
| 125 | + }) |
| 126 | + } |
| 127 | + None => unsafe { |
| 128 | + llvm::LLVMDIBuilderCreateLexicalBlock( |
| 129 | + DIB(cx), |
| 130 | + parent_scope.dbg_scope, |
| 131 | + file_metadata, |
| 132 | + loc.line, |
| 133 | + loc.col, |
| 134 | + ) |
| 135 | + }, |
| 136 | + }; |
| 137 | + |
| 138 | + let inlined_at = scope_data.inlined.map(|(_, callsite_span)| { |
| 139 | + let callsite_span = hygiene::walk_chain_collapsed(callsite_span, mir.span); |
| 140 | + let callsite_scope = parent_scope.adjust_dbg_scope_for_span(cx, callsite_span); |
| 141 | + let loc = cx.dbg_loc(callsite_scope, parent_scope.inlined_at, callsite_span); |
| 142 | + |
| 143 | + // NB: In order to produce proper debug info for variables (particularly |
| 144 | + // arguments) in multiply-inlined functions, LLVM expects to see a single |
| 145 | + // DILocalVariable with multiple different DILocations in the IR. While |
| 146 | + // the source information for each DILocation would be identical, their |
| 147 | + // inlinedAt attributes will be unique to the particular callsite. |
| 148 | + // |
| 149 | + // We generate DILocations here based on the callsite's location in the |
| 150 | + // source code. A single location in the source code usually can't |
| 151 | + // produce multiple distinct calls so this mostly works, until |
| 152 | + // macros get involved. A macro can generate multiple calls |
| 153 | + // at the same span, which breaks the assumption that we're going to |
| 154 | + // produce a unique DILocation for every scope we process here. We |
| 155 | + // have to explicitly add discriminators if we see inlines into the |
| 156 | + // same source code location. |
| 157 | + // |
| 158 | + // Note further that we can't key this hashtable on the span itself, |
| 159 | + // because these spans could have distinct SyntaxContexts. We have |
| 160 | + // to key on exactly what we're giving to LLVM. |
| 161 | + match discriminators.entry(callsite_span.lo()) { |
| 162 | + Entry::Occupied(mut o) => { |
| 163 | + *o.get_mut() += 1; |
| 164 | + // NB: We have to emit *something* here or we'll fail LLVM IR verification |
| 165 | + // in at least some circumstances (see issue #135322) so if the required |
| 166 | + // discriminant cannot be encoded fall back to the dummy location. |
| 167 | + unsafe { llvm::LLVMRustDILocationCloneWithBaseDiscriminator(loc, *o.get()) } |
| 168 | + .unwrap_or_else(|| { |
| 169 | + cx.dbg_loc(callsite_scope, parent_scope.inlined_at, DUMMY_SP) |
| 170 | + }) |
| 171 | + } |
| 172 | + Entry::Vacant(v) => { |
| 173 | + v.insert(0); |
| 174 | + loc |
| 175 | + } |
| 176 | + } |
| 177 | + }); |
| 178 | + |
| 179 | + debug_context.scopes[scope] = DebugScope { |
| 180 | + dbg_scope, |
| 181 | + inlined_at: inlined_at.or(parent_scope.inlined_at), |
| 182 | + file_start_pos: loc.file.start_pos, |
| 183 | + file_end_pos: loc.file.end_position(), |
| 184 | + }; |
| 185 | + instantiated.insert(scope); |
| 186 | +} |
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