From a1efc4be8f5a46d223bf6e24f5d61e23fe94b1ed Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Fri, 23 Jan 2026 13:05:53 -0800 Subject: [PATCH] Mangle class declarations #6617 (#6648) In some situations we need to mangle class declarations, which then are not NameScopes (can't scope anything inside a declaration) - so make the mangler able to cope with that situation by mangling the name of the class directly rather than relying on generic NameScope mangling to handle the class case. --- toolchain/lower/mangler.cpp | 24 +++++++---- toolchain/lower/mangler.h | 5 +++ .../interface/mangle_declared_class.carbon | 42 +++++++++++++++++++ 3 files changed, 64 insertions(+), 7 deletions(-) create mode 100644 toolchain/lower/testdata/interface/mangle_declared_class.carbon diff --git a/toolchain/lower/mangler.cpp b/toolchain/lower/mangler.cpp index f59b6018faf5..a1934df730d9 100644 --- a/toolchain/lower/mangler.cpp +++ b/toolchain/lower/mangler.cpp @@ -83,11 +83,15 @@ auto Mangler::MangleInverseQualifiedNameScope(llvm::raw_ostream& os, auto self_inst = insts().Get(self_const_inst_id); CARBON_KIND_SWITCH(self_inst) { case CARBON_KIND(SemIR::ClassType class_type): { - auto next_name_scope_id = - sem_ir().classes().Get(class_type.class_id).scope_id; - names_to_render.push_back({.name_scope_id = next_name_scope_id, - .specific_id = class_type.specific_id, - .prefix = '\0'}); + const auto& class_info = + sem_ir().classes().Get(class_type.class_id); + + names_to_render.push_back( + {.name_scope_id = class_info.parent_scope_id, + .specific_id = class_type.specific_id, + .prefix = '.'}); + + MangleUnqualifiedClass(os, class_info, class_type.specific_id); break; } case SemIR::AutoType::Kind: @@ -128,8 +132,8 @@ auto Mangler::MangleInverseQualifiedNameScope(llvm::raw_ostream& os, continue; } case CARBON_KIND(SemIR::ClassDecl class_decl): { - MangleNameId(os, sem_ir().classes().Get(class_decl.class_id).name_id); - MangleSpecificId(os, specific_id); + MangleUnqualifiedClass(os, sem_ir().classes().Get(class_decl.class_id), + specific_id); break; } case CARBON_KIND(SemIR::InterfaceDecl interface_decl): { @@ -264,4 +268,10 @@ auto Mangler::MangleVTable(const SemIR::Class& class_info, return os.TakeStr(); } +auto Mangler::MangleUnqualifiedClass(llvm::raw_ostream& os, + const SemIR::Class& class_info, + SemIR::SpecificId specific_id) -> void { + MangleNameId(os, class_info.name_id); + MangleSpecificId(os, specific_id); +} } // namespace Carbon::Lower diff --git a/toolchain/lower/mangler.h b/toolchain/lower/mangler.h index 2cd809a1e8a9..70076aac61fe 100644 --- a/toolchain/lower/mangler.h +++ b/toolchain/lower/mangler.h @@ -58,6 +58,11 @@ class Mangler { SemIR::NameScopeId name_scope_id) -> void; + // Mangle the unqualified name of the specified `Class`. + auto MangleUnqualifiedClass(llvm::raw_ostream& os, + const SemIR::Class& class_info, + SemIR::SpecificId specific_id) -> void; + // Generates a mangled name using Clang mangling for imported C++ functions. auto MangleCppClang(const clang::NamedDecl* decl) -> std::string; diff --git a/toolchain/lower/testdata/interface/mangle_declared_class.carbon b/toolchain/lower/testdata/interface/mangle_declared_class.carbon new file mode 100644 index 000000000000..38fad6c806dc --- /dev/null +++ b/toolchain/lower/testdata/interface/mangle_declared_class.carbon @@ -0,0 +1,42 @@ +// Part of the Carbon Language project, under the Apache License v2.0 with LLVM +// Exceptions. See /LICENSE for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/convert.carbon +// +// AUTOUPDATE +// TIP: To test this file alone, run: +// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/lower/testdata/interface/mangle_declared_class.carbon +// TIP: To dump output, run: +// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/interface/mangle_declared_class.carbon + +interface I { + fn F(); +} +class C; +impl C as I { + fn F() {} +} + +// CHECK:STDOUT: ; ModuleID = 'mangle_declared_class.carbon' +// CHECK:STDOUT: source_filename = "mangle_declared_class.carbon" +// CHECK:STDOUT: +// CHECK:STDOUT: ; Function Attrs: nounwind +// CHECK:STDOUT: define void @"_CF.C.Main:I.Main"() #0 !dbg !4 { +// CHECK:STDOUT: entry: +// CHECK:STDOUT: ret void, !dbg !7 +// CHECK:STDOUT: } +// CHECK:STDOUT: +// CHECK:STDOUT: attributes #0 = { nounwind } +// CHECK:STDOUT: +// CHECK:STDOUT: !llvm.module.flags = !{!0, !1} +// CHECK:STDOUT: !llvm.dbg.cu = !{!2} +// CHECK:STDOUT: +// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5} +// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3} +// CHECK:STDOUT: !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug) +// CHECK:STDOUT: !3 = !DIFile(filename: "mangle_declared_class.carbon", directory: "") +// CHECK:STDOUT: !4 = distinct !DISubprogram(name: "F", linkageName: "_CF.C.Main:I.Main", scope: null, file: !3, line: 18, type: !5, spFlags: DISPFlagDefinition, unit: !2) +// CHECK:STDOUT: !5 = !DISubroutineType(types: !6) +// CHECK:STDOUT: !6 = !{null} +// CHECK:STDOUT: !7 = !DILocation(line: 18, column: 3, scope: !4)