carbon-language/carbon-lang
1
0
Fork 0
mirror of https://github.com/carbon-language/carbon-lang.git synced 2026-10-05 22:02:55 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

C++ interop: Add return reference types support (#6178)

Browse Source 
This is a follow up of #6082, which added support for reference types,
but not for return types.

C++ Interop Demo:

```carbon
// main.carbon

library "Main";

import Core library "io";

import Cpp inline '''
struct C {
  auto Inc() -> void { ++x; }
  int x = 0;
};
auto GetC() -> C& {
  static C c;
  return c;
}
''';

fn Run() -> i32 {
  Core.Print(Cpp.GetC()->x);
  Cpp.GetC()->Inc();
  Core.Print(Cpp.GetC()->x);
  Cpp.GetC()->Inc();
  Core.Print(Cpp.GetC()->x);
  return 0;
}
```

```shell
$ bazel build toolchain:carbon && bazel-bin/toolchain/carbon compile main.carbon && bazel-bin/toolchain/carbon link main.o --output=demo && ./demo
0
1
2
```

**Without this change**:
```shell
main.carbon:19:14: error: semantics TODO: `Unsupported: return type: C &`
  Core.Print(Cpp.GetC()->x);
             ^~~~~~~~~~
```

Part of #6148.
This commit is contained in:
Boaz Brickner
2025-10-08 16:33:09 +00:00
committed by GitHub
parent ba8ed99eb0
commit bfc4d2b127
4 changed files with 268 additions and 111 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/lower/testdata/interop/cpp/reference.carbon
Vendored
+156 -33
View File
@@ -10,23 +10,25 @@
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/interop/cpp/reference.carbon
// --- reference_params.h
class C {};
void TakeCRef(C&);
void TakeCRRef(C&&);
void TakeConstCRef(const C&);
void TakeIntRef(int&);
void TakeIntRRef(int&&);
void TakeConstIntRef(const int&);
// ============================================================================
// Reference params
// ============================================================================
// --- pass_references.carbon
library "[[@TEST_NAME]]";
import Cpp library "reference_params.h";
import Cpp inline '''
class C {};
auto TakeCRef(C&) -> void;
auto TakeCRRef(C&&) -> void;
auto TakeConstCRef(const C&) -> void;
auto TakeIntRef(int&) -> void;
auto TakeIntRRef(int&&) -> void;
auto TakeConstIntRef(const int&) -> void;
''';
fn PassRefs() {
var c: Cpp.C;
@@ -40,30 +42,60 @@ fn PassRefs() {
Cpp.TakeConstIntRef(n);
}
// ============================================================================
// Reference return values
// ============================================================================
// --- return_references.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
class C {};
auto ReturnCRef() -> C&;
auto ReturnCRRef() -> C&&;
auto ReturnConstCRef() -> const C&;
auto ReturnIntRef() -> int&;
auto ReturnIntRRef() -> int&&;
auto ReturnConstIntRef() -> const int&;
''';
fn GetRefs() {
var c1: Cpp.C* = Cpp.ReturnCRef();
var c2: Cpp.C = Cpp.ReturnCRRef();
var c3: const Cpp.C* = Cpp.ReturnConstCRef();
var n1: i32* = Cpp.ReturnIntRef();
var n2: i32 = Cpp.ReturnIntRRef();
var n3: const i32* = Cpp.ReturnConstIntRef();
}
// CHECK:STDOUT: ; ModuleID = 'pass_references.carbon'
// CHECK:STDOUT: source_filename = "pass_references.carbon"
// CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
// CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
// CHECK:STDOUT:
// CHECK:STDOUT: @C.val.loc9_18.3 = internal constant {} zeroinitializer
// CHECK:STDOUT: @C.val.loc19_18.3 = internal constant {} zeroinitializer
// CHECK:STDOUT:
// CHECK:STDOUT: define void @_CPassRefs.Main() !dbg !7 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %c.var = alloca {}, align 8, !dbg !10
// CHECK:STDOUT: %.loc9_18.2.temp = alloca {}, align 8, !dbg !11
// CHECK:STDOUT: %.loc19_18.2.temp = alloca {}, align 8, !dbg !11
// CHECK:STDOUT: %n.var = alloca i32, align 4, !dbg !12
// CHECK:STDOUT: %.loc14_22.3.temp = alloca i32, align 4, !dbg !13
// CHECK:STDOUT: %.loc24_22.3.temp = alloca i32, align 4, !dbg !13
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !10
// CHECK:STDOUT: call void @_Z8TakeCRefR1C.carbon_thunk(ptr %c.var), !dbg !14
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc9_18.2.temp), !dbg !11
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc9_18.2.temp, ptr align 1 @C.val.loc9_18.3, i64 0, i1 false), !dbg !11
// CHECK:STDOUT: call void @_Z9TakeCRRefO1C.carbon_thunk(ptr %.loc9_18.2.temp), !dbg !15
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !11
// CHECK:STDOUT: call void @llvm.memcpy.p0.p0.i64(ptr align 1 %.loc19_18.2.temp, ptr align 1 @C.val.loc19_18.3, i64 0, i1 false), !dbg !11
// CHECK:STDOUT: call void @_Z9TakeCRRefO1C.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !15
// CHECK:STDOUT: call void @_Z13TakeConstCRefRK1C.carbon_thunk(ptr %c.var), !dbg !16
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %n.var), !dbg !12
// CHECK:STDOUT: call void @_Z10TakeIntRefRi.carbon_thunk(ptr %n.var), !dbg !17
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc14_22.3.temp), !dbg !13
// CHECK:STDOUT: store i32 42, ptr %.loc14_22.3.temp, align 4, !dbg !13
// CHECK:STDOUT: call void @_Z11TakeIntRRefOi.carbon_thunk(ptr %.loc14_22.3.temp), !dbg !18
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc24_22.3.temp), !dbg !13
// CHECK:STDOUT: store i32 42, ptr %.loc24_22.3.temp, align 4, !dbg !13
// CHECK:STDOUT: call void @_Z11TakeIntRRefOi.carbon_thunk(ptr %.loc24_22.3.temp), !dbg !18
// CHECK:STDOUT: call void @_Z15TakeConstIntRefRKi.carbon_thunk(ptr %n.var), !dbg !19
// CHECK:STDOUT: ret void, !dbg !20
// CHECK:STDOUT: }
@@ -164,17 +196,108 @@ fn PassRefs() {
// CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !6 = !DIFile(filename: "pass_references.carbon", directory: "")
// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !6, line: 6, type: !8, spFlags: DISPFlagDefinition, unit: !5)
// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "PassRefs", linkageName: "_CPassRefs.Main", scope: null, file: !6, line: 16, type: !8, spFlags: DISPFlagDefinition, unit: !5)
// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
// CHECK:STDOUT: !9 = !{}
// CHECK:STDOUT: !10 = !DILocation(line: 7, column: 3, scope: !7)
// CHECK:STDOUT: !11 = !DILocation(line: 9, column: 17, scope: !7)
// CHECK:STDOUT: !12 = !DILocation(line: 12, column: 3, scope: !7)
// CHECK:STDOUT: !13 = !DILocation(line: 14, column: 19, scope: !7)
// CHECK:STDOUT: !14 = !DILocation(line: 8, column: 3, scope: !7)
// CHECK:STDOUT: !15 = !DILocation(line: 9, column: 3, scope: !7)
// CHECK:STDOUT: !16 = !DILocation(line: 10, column: 3, scope: !7)
// CHECK:STDOUT: !17 = !DILocation(line: 13, column: 3, scope: !7)
// CHECK:STDOUT: !18 = !DILocation(line: 14, column: 3, scope: !7)
// CHECK:STDOUT: !19 = !DILocation(line: 15, column: 3, scope: !7)
// CHECK:STDOUT: !20 = !DILocation(line: 6, column: 1, scope: !7)
// CHECK:STDOUT: !10 = !DILocation(line: 17, column: 3, scope: !7)
// CHECK:STDOUT: !11 = !DILocation(line: 19, column: 17, scope: !7)
// CHECK:STDOUT: !12 = !DILocation(line: 22, column: 3, scope: !7)
// CHECK:STDOUT: !13 = !DILocation(line: 24, column: 19, scope: !7)
// CHECK:STDOUT: !14 = !DILocation(line: 18, column: 3, scope: !7)
// CHECK:STDOUT: !15 = !DILocation(line: 19, column: 3, scope: !7)
// CHECK:STDOUT: !16 = !DILocation(line: 20, column: 3, scope: !7)
// CHECK:STDOUT: !17 = !DILocation(line: 23, column: 3, scope: !7)
// CHECK:STDOUT: !18 = !DILocation(line: 24, column: 3, scope: !7)
// CHECK:STDOUT: !19 = !DILocation(line: 25, column: 3, scope: !7)
// CHECK:STDOUT: !20 = !DILocation(line: 16, column: 1, scope: !7)
// CHECK:STDOUT: ; ModuleID = 'return_references.carbon'
// CHECK:STDOUT: source_filename = "return_references.carbon"
// CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
// CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
// CHECK:STDOUT:
// CHECK:STDOUT: define void @_CGetRefs.Main() !dbg !7 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %c1.var = alloca ptr, align 8, !dbg !10
// CHECK:STDOUT: %c2.var = alloca {}, align 8, !dbg !11
// CHECK:STDOUT: %c3.var = alloca ptr, align 8, !dbg !12
// CHECK:STDOUT: %n1.var = alloca ptr, align 8, !dbg !13
// CHECK:STDOUT: %n2.var = alloca i32, align 4, !dbg !14
// CHECK:STDOUT: %n3.var = alloca ptr, align 8, !dbg !15
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %c1.var), !dbg !10
// CHECK:STDOUT: %ReturnCRef.call = call ptr @_Z10ReturnCRefv(), !dbg !16
// CHECK:STDOUT: store ptr %ReturnCRef.call, ptr %c1.var, align 8, !dbg !10
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %c2.var), !dbg !11
// CHECK:STDOUT: call void @_Z11ReturnCRRefv.carbon_thunk(ptr %c2.var), !dbg !17
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %c3.var), !dbg !12
// CHECK:STDOUT: %ReturnConstCRef.call = call ptr @_Z15ReturnConstCRefv(), !dbg !18
// CHECK:STDOUT: store ptr %ReturnConstCRef.call, ptr %c3.var, align 8, !dbg !12
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %n1.var), !dbg !13
// CHECK:STDOUT: %ReturnIntRef.call = call ptr @_Z12ReturnIntRefv(), !dbg !19
// CHECK:STDOUT: store ptr %ReturnIntRef.call, ptr %n1.var, align 8, !dbg !13
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %n2.var), !dbg !14
// CHECK:STDOUT: %ReturnIntRRef.call = call i32 @_Z13ReturnIntRRefv(), !dbg !20
// CHECK:STDOUT: store i32 %ReturnIntRRef.call, ptr %n2.var, align 4, !dbg !14
// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %n3.var), !dbg !15
// CHECK:STDOUT: %ReturnConstIntRef.call = call ptr @_Z17ReturnConstIntRefv(), !dbg !21
// CHECK:STDOUT: store ptr %ReturnConstIntRef.call, ptr %n3.var, align 8, !dbg !15
// CHECK:STDOUT: ret void, !dbg !22
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: declare ptr @_Z10ReturnCRefv()
// CHECK:STDOUT:
// CHECK:STDOUT: declare ptr @_Z15ReturnConstCRefv()
// CHECK:STDOUT:
// CHECK:STDOUT: declare ptr @_Z12ReturnIntRefv()
// CHECK:STDOUT:
// CHECK:STDOUT: declare i32 @_Z13ReturnIntRRefv()
// CHECK:STDOUT:
// CHECK:STDOUT: declare ptr @_Z17ReturnConstIntRefv()
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #0
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: alwaysinline mustprogress
// CHECK:STDOUT: define dso_local void @_Z11ReturnCRRefv.carbon_thunk(ptr %return) #1 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: %return.addr = alloca ptr, align 8
// CHECK:STDOUT: store ptr %return, ptr %return.addr, align 8
// CHECK:STDOUT: %0 = load ptr, ptr %return.addr, align 8
// CHECK:STDOUT: %call = call nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRefv()
// CHECK:STDOUT: ret void
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: declare nonnull align 1 dereferenceable(1) ptr @_Z11ReturnCRRefv() #2
// CHECK:STDOUT:
// CHECK:STDOUT: ; uselistorder directives
// CHECK:STDOUT: uselistorder ptr @llvm.lifetime.start.p0, { 5, 4, 3, 2, 1, 0 }
// CHECK:STDOUT:
// CHECK:STDOUT: attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
// CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="0" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
// CHECK:STDOUT: attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="0" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
// CHECK:STDOUT:
// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
// CHECK:STDOUT: !llvm.dbg.cu = !{!5}
// CHECK:STDOUT:
// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
// CHECK:STDOUT: !2 = !{i32 1, !"wchar_size", i32 4}
// CHECK:STDOUT: !3 = !{i32 8, !"PIC Level", i32 0}
// CHECK:STDOUT: !4 = !{i32 7, !"PIE Level", i32 2}
// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
// CHECK:STDOUT: !6 = !DIFile(filename: "return_references.carbon", directory: "")
// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "GetRefs", linkageName: "_CGetRefs.Main", scope: null, file: !6, line: 16, type: !8, spFlags: DISPFlagDefinition, unit: !5)
// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
// CHECK:STDOUT: !9 = !{}
// CHECK:STDOUT: !10 = !DILocation(line: 17, column: 3, scope: !7)
// CHECK:STDOUT: !11 = !DILocation(line: 18, column: 3, scope: !7)
// CHECK:STDOUT: !12 = !DILocation(line: 19, column: 3, scope: !7)
// CHECK:STDOUT: !13 = !DILocation(line: 21, column: 3, scope: !7)
// CHECK:STDOUT: !14 = !DILocation(line: 22, column: 3, scope: !7)
// CHECK:STDOUT: !15 = !DILocation(line: 23, column: 3, scope: !7)
// CHECK:STDOUT: !16 = !DILocation(line: 17, column: 20, scope: !7)
// CHECK:STDOUT: !17 = !DILocation(line: 18, column: 19, scope: !7)
// CHECK:STDOUT: !18 = !DILocation(line: 19, column: 26, scope: !7)
// CHECK:STDOUT: !19 = !DILocation(line: 21, column: 18, scope: !7)
// CHECK:STDOUT: !20 = !DILocation(line: 22, column: 17, scope: !7)
// CHECK:STDOUT: !21 = !DILocation(line: 23, column: 24, scope: !7)
// CHECK:STDOUT: !22 = !DILocation(line: 16, column: 1, scope: !7)