Handle merging of conflicting 'export name' cross-package imports. (#3973)

2026-10-05 22:02:55 +01:00 · 2024-05-22 22:35:48 +00:00
parent 41a84222c2
commit d4025dc6c4
5 changed files with 267 additions and 170 deletions
@@ -72,6 +72,56 @@ auto AddImportRef(Context& context, SemIR::ImportIRInst import_ir_inst,
  return import_ref_id;
 }

+auto GetCanonicalImportIRInst(Context& context, const SemIR::File* cursor_ir,
+                              SemIR::InstId cursor_inst_id)
+    -> SemIR::ImportIRInst {
+  while (true) {
+    auto inst = cursor_ir->insts().Get(cursor_inst_id);
+    CARBON_KIND_SWITCH(inst) {
+      case CARBON_KIND(SemIR::ExportDecl bind_export): {
+        cursor_inst_id = bind_export.value_id;
+        continue;
+      }
+      case SemIR::ImportRefLoaded::Kind:
+      case SemIR::ImportRefUnloaded::Kind: {
+        auto import_ref = inst.As<SemIR::AnyImportRef>();
+        auto import_ir_inst =
+            cursor_ir->import_ir_insts().Get(import_ref.import_ir_inst_id);
+        cursor_ir = cursor_ir->import_irs().Get(import_ir_inst.ir_id).sem_ir;
+        cursor_inst_id = import_ir_inst.inst_id;
+        continue;
+      }
+      default: {
+        auto ir_id = SemIR::ImportIRId::Invalid;
+        if (cursor_ir != &context.sem_ir()) {
+          // This uses AddImportIR in case it was indirectly found, which can
+          // happen with two or more steps of exports.
+          ir_id = AddImportIR(context, {.node_id = Parse::NodeId::Invalid,
+                                        .sem_ir = cursor_ir,
+                                        .is_export = false});
+        }
+        return {.ir_id = ir_id, .inst_id = cursor_inst_id};
+      }
+    }
+  }
+}
+
+auto VerifySameCanonicalImportIRInst(Context& context, SemIR::InstId prev_id,
+                                     SemIR::ImportIRInst prev_import_ir_inst,
+                                     SemIR::ImportIRId new_ir_id,
+                                     const SemIR::File* new_import_ir,
+                                     SemIR::InstId new_inst_id) -> void {
+  auto new_import_ir_inst =
+      GetCanonicalImportIRInst(context, new_import_ir, new_inst_id);
+  if (new_import_ir_inst == prev_import_ir_inst) {
+    return;
+  }
+  auto conflict_id =
+      AddImportRef(context, {.ir_id = new_ir_id, .inst_id = new_inst_id},
+                   SemIR::BindNameId::Invalid);
+  context.DiagnoseDuplicateName(conflict_id, prev_id);
+}
+
 // Resolves an instruction from an imported IR into a constant referring to the
 // current IR.
 //