Export Carbon global variables and static vars to C++ (#7298)

Add `ExportVarToCpp`. This checks the `clang_decls` mapping and returns
an existing decl if found. Otherwise, it creates a new `VarDecl` and
adds it to the `clang_decls` mapping.

When lowering, in `FileContext::BuildGlobalVariableDecl`, the
`clang_decls` mapping is used to lookup an existing
`llvm::GlobalVariable` for the instruction. If found, use that rather
than creating a new one to avoid an unwanted second definition in the
llvm IR.
This commit is contained in:
Nicholas Bishop
2026-06-03 20:47:54 +00:00
committed by GitHub
parent 76dd872ab4
commit f2d0c4d0ae
12 changed files with 354 additions and 11 deletions
@@ -0,0 +1,61 @@
// 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/full.carbon
// EXTRA-ARGS: --clang-arg=--std=c++20
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/var/import/constexpr.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/var/import/constexpr.carbon
// --- bool.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr bool b = true;
''';
class C(B:! bool) {}
fn F() -> C(Cpp.b);
let x: C(true) = F();
// --- int.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr int i = 123;
''';
class C(I:! i32) {}
fn F() -> C(Cpp.i);
let x: C(123) = F();
// --- float.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr float flt = 123.5;
''';
class C(V:! f32) {}
fn F() -> C(Cpp.flt);
let x: C(123.5) = F();
// --- pointer.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
int i = 123;
constexpr int* _Nonnull ptr = &i;
''';
class C(V:! i32*) {}
fn F() -> C(Cpp.ptr);
let x: C(&Cpp.i) = F();
@@ -0,0 +1,224 @@
// 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/destroy.carbon
// EXTRA-ARGS: --dump-sem-ir-ranges=if-present
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/var/import/global.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/var/import/global.carbon
// ============================================================================
// Global scope
// ============================================================================
// --- global_scope.h
class C {};
C global;
C* _Nonnull global_ptr = &global;
C& global_ref = global;
// --- import_global_scope.carbon
library "[[@TEST_NAME]]";
import Cpp library "global_scope.h";
fn MyF() {
let unused local: Cpp.C = Cpp.global;
let unused local_ptr: Cpp.C* = Cpp.global_ptr;
let unused local_ref: Cpp.C* = Cpp.global_ref;
}
// ============================================================================
// Unsupported global type
// ============================================================================
// --- unsupported_type.h
using UnusupportedType = _BitInt(23);
UnusupportedType global;
// --- fail_import_unsupported_type.carbon
library "[[@TEST_NAME]]";
// CHECK:STDERR: fail_import_unsupported_type.carbon:[[@LINE+4]]:10: in file included here [InCppInclude]
// CHECK:STDERR: ./unsupported_type.h:2:7: error: semantics TODO: `Unsupported: Type declaration: UnusupportedType` [SemanticsTodo]
// CHECK:STDERR: using UnusupportedType = _BitInt(23);
// CHECK:STDERR: ^
import Cpp library "unsupported_type.h";
fn MyF() {
// CHECK:STDERR: fail_import_unsupported_type.carbon:[[@LINE+11]]:21: note: in `Cpp` name lookup for `UnusupportedType` [InCppNameLookup]
// CHECK:STDERR: let unused local: Cpp.UnusupportedType = Cpp.global;
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
// CHECK:STDERR: fail_import_unsupported_type.carbon:[[@LINE+7]]:44: error: semantics TODO: `Unsupported: var type: UnusupportedType` [SemanticsTodo]
// CHECK:STDERR: let unused local: Cpp.UnusupportedType = Cpp.global;
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR: fail_import_unsupported_type.carbon:[[@LINE+4]]:44: note: in `Cpp` name lookup for `global` [InCppNameLookup]
// CHECK:STDERR: let unused local: Cpp.UnusupportedType = Cpp.global;
// CHECK:STDERR: ^~~~~~~~~~
// CHECK:STDERR:
let unused local: Cpp.UnusupportedType = Cpp.global;
}
// CHECK:STDOUT: --- import_global_scope.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: %MyF.type: type = fn_type @MyF [concrete]
// CHECK:STDOUT: %MyF: %MyF.type = struct_value () [concrete]
// CHECK:STDOUT: %C: type = class_type @C [concrete]
// CHECK:STDOUT: %empty_struct_type: type = struct_type {} [concrete]
// CHECK:STDOUT: %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
// CHECK:STDOUT: %pattern_type.479: type = pattern_type %C [concrete]
// CHECK:STDOUT: %ptr.3a8: type = ptr_type %C [concrete]
// CHECK:STDOUT: %pattern_type.0d0: type = pattern_type %ptr.3a8 [concrete]
// CHECK:STDOUT: %const: type = const_type %ptr.3a8 [concrete]
// CHECK:STDOUT: %pattern_type.3f2: type = pattern_type %const [concrete]
// CHECK:STDOUT: %global_ref.var: ref %ptr.3a8 = var imports.%global_ref.var_patt [concrete]
// CHECK:STDOUT: %addr: %ptr.3a8 = addr_of imports.%global.var [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: %Core: <namespace> = namespace file.%Core.import, [concrete] {
// CHECK:STDOUT: import Core//prelude
// CHECK:STDOUT: import Core//prelude/...
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
// CHECK:STDOUT: .C = %C.decl
// CHECK:STDOUT: .global = %global.var
// CHECK:STDOUT: .global_ptr = %global_ptr.var
// CHECK:STDOUT: .global_ref = %global_ref.var
// CHECK:STDOUT: import Cpp//...
// CHECK:STDOUT: }
// CHECK:STDOUT: %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
// CHECK:STDOUT: %global.patt: %pattern_type.479 = ref_binding_pattern global [concrete]
// CHECK:STDOUT: %global.var_patt: %pattern_type.479 = var_pattern %global.patt [concrete]
// CHECK:STDOUT: %global.var: ref %C = var %global.var_patt [concrete]
// CHECK:STDOUT: %global_ptr.patt: %pattern_type.0d0 = ref_binding_pattern global_ptr [concrete]
// CHECK:STDOUT: %global_ptr.var_patt: %pattern_type.0d0 = var_pattern %global_ptr.patt [concrete]
// CHECK:STDOUT: %global_ptr.var: ref %ptr.3a8 = var %global_ptr.var_patt [concrete]
// CHECK:STDOUT: %global_ref.patt: %pattern_type.3f2 = ref_binding_pattern global_ref [concrete]
// CHECK:STDOUT: %global_ref.var_patt: %pattern_type.3f2 = var_pattern %global_ref.patt [concrete]
// CHECK:STDOUT: %global_ref.var: ref %const = var %global_ref.var_patt [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: file {
// CHECK:STDOUT: package: <namespace> = namespace [concrete] {
// CHECK:STDOUT: .Core = imports.%Core
// CHECK:STDOUT: .Cpp = imports.%Cpp
// CHECK:STDOUT: .MyF = %MyF.decl
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.import = import Core
// CHECK:STDOUT: %Cpp.import_cpp = import_cpp {
// CHECK:STDOUT: import Cpp "global_scope.h"
// CHECK:STDOUT: }
// CHECK:STDOUT: %MyF.decl: %MyF.type = fn_decl @MyF [concrete = constants.%MyF] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: class @C {
// CHECK:STDOUT: %empty_struct_type: type = struct_type {} [concrete = constants.%empty_struct_type]
// CHECK:STDOUT: %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete = constants.%complete_type]
// CHECK:STDOUT: complete_type_witness = %complete_type
// CHECK:STDOUT:
// CHECK:STDOUT: !members:
// CHECK:STDOUT: import Cpp//...
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: fn @MyF() {
// CHECK:STDOUT: !entry:
// CHECK:STDOUT: name_binding_decl {
// CHECK:STDOUT: %local.patt: %pattern_type.479 = value_binding_pattern local [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp.ref.loc7_29: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %global.ref: ref %C = name_ref global, imports.%global.var [concrete = imports.%global.var]
// CHECK:STDOUT: %.loc7_24: type = splice_block %C.ref.loc7 [concrete = constants.%C] {
// CHECK:STDOUT: %Cpp.ref.loc7_21: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %C.ref.loc7: type = name_ref C, imports.%C.decl [concrete = constants.%C]
// CHECK:STDOUT: }
// CHECK:STDOUT: %.loc7_32: %C = acquire_value %global.ref
// CHECK:STDOUT: %local: %C = value_binding local, %.loc7_32
// CHECK:STDOUT: name_binding_decl {
// CHECK:STDOUT: %local_ptr.patt: %pattern_type.0d0 = value_binding_pattern local_ptr [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp.ref.loc8_34: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %global_ptr.ref: ref %ptr.3a8 = name_ref global_ptr, imports.%global_ptr.var [concrete = imports.%global_ptr.var]
// CHECK:STDOUT: %.loc8_30: type = splice_block %ptr.loc8 [concrete = constants.%ptr.3a8] {
// CHECK:STDOUT: %Cpp.ref.loc8_25: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %C.ref.loc8: type = name_ref C, imports.%C.decl [concrete = constants.%C]
// CHECK:STDOUT: %ptr.loc8: type = ptr_type %C.ref.loc8 [concrete = constants.%ptr.3a8]
// CHECK:STDOUT: }
// CHECK:STDOUT: %.loc8_37: %ptr.3a8 = acquire_value %global_ptr.ref
// CHECK:STDOUT: %local_ptr: %ptr.3a8 = value_binding local_ptr, %.loc8_37
// CHECK:STDOUT: name_binding_decl {
// CHECK:STDOUT: %local_ref.patt: %pattern_type.0d0 = value_binding_pattern local_ref [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp.ref.loc9_34: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %global_ref.ref: ref %const = name_ref global_ref, imports.%global_ref.var [concrete = imports.%global_ref.var]
// CHECK:STDOUT: %.loc9_30: type = splice_block %ptr.loc9 [concrete = constants.%ptr.3a8] {
// CHECK:STDOUT: %Cpp.ref.loc9_25: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %C.ref.loc9: type = name_ref C, imports.%C.decl [concrete = constants.%C]
// CHECK:STDOUT: %ptr.loc9: type = ptr_type %C.ref.loc9 [concrete = constants.%ptr.3a8]
// CHECK:STDOUT: }
// CHECK:STDOUT: %.loc9_37.1: ref %ptr.3a8 = as_compatible %global_ref.ref [concrete = constants.%global_ref.var]
// CHECK:STDOUT: %.loc9_37.2: ref %ptr.3a8 = converted %global_ref.ref, %.loc9_37.1 [concrete = constants.%global_ref.var]
// CHECK:STDOUT: %addr: %ptr.3a8 = addr_of imports.%global.var [concrete = constants.%addr]
// CHECK:STDOUT: %.loc9_37.3: %ptr.3a8 = acquire_value %.loc9_37.2 [concrete = constants.%addr]
// CHECK:STDOUT: %local_ref: %ptr.3a8 = value_binding local_ref, %.loc9_37.3
// CHECK:STDOUT: return
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: --- fail_import_unsupported_type.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: %MyF.type: type = fn_type @MyF [concrete]
// CHECK:STDOUT: %MyF: %MyF.type = struct_value () [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: %Core: <namespace> = namespace file.%Core.import, [concrete] {
// CHECK:STDOUT: import Core//prelude
// CHECK:STDOUT: import Core//prelude/...
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
// CHECK:STDOUT: .UnusupportedType = <error>
// CHECK:STDOUT: .global = <error>
// CHECK:STDOUT: import Cpp//...
// CHECK:STDOUT: }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: file {
// CHECK:STDOUT: package: <namespace> = namespace [concrete] {
// CHECK:STDOUT: .Core = imports.%Core
// CHECK:STDOUT: .Cpp = imports.%Cpp
// CHECK:STDOUT: .MyF = %MyF.decl
// CHECK:STDOUT: }
// CHECK:STDOUT: %Core.import = import Core
// CHECK:STDOUT: %Cpp.import_cpp = import_cpp {
// CHECK:STDOUT: import Cpp "unsupported_type.h"
// CHECK:STDOUT: }
// CHECK:STDOUT: %MyF.decl: %MyF.type = fn_decl @MyF [concrete = constants.%MyF] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: fn @MyF() {
// CHECK:STDOUT: !entry:
// CHECK:STDOUT: name_binding_decl {
// CHECK:STDOUT: %local.patt: <error> = value_binding_pattern local [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp.ref.loc22_44: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %global.ref: <error> = name_ref global, <error> [concrete = <error>]
// CHECK:STDOUT: %.1: <error> = splice_block <error> [concrete = <error>] {
// CHECK:STDOUT: %Cpp.ref.loc22_21: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %UnusupportedType.ref: <error> = name_ref UnusupportedType, <error> [concrete = <error>]
// CHECK:STDOUT: }
// CHECK:STDOUT: %local: <error> = value_binding local, <error> [concrete = <error>]
// CHECK:STDOUT: return
// CHECK:STDOUT: }
// CHECK:STDOUT:
@@ -0,0 +1,77 @@
// 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/none.carbon
//
// AUTOUPDATE
// TIP: To test this file alone, run:
// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/interop/cpp/var/import/namespace.carbon
// TIP: To dump output, run:
// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/interop/cpp/var/import/namespace.carbon
// --- namespace.h
namespace N {
class C {};
C global;
} // namespace N
// --- import_namespace.carbon
library "[[@TEST_NAME]]";
import Cpp library "namespace.h";
fn MyF() {
let unused local: Cpp.N.C = Cpp.N.global;
}
// --- type_in_namespace.carbon
import Cpp inline '''
namespace N {
class C {};
}
extern N::C c;
''';
//@dump-sem-ir-begin
fn F() {
// Import `::c` and its type `N::C` without having ever mentioned `N`.
// This used to cause a crash.
Cpp.c;
}
//@dump-sem-ir-end
// CHECK:STDOUT: --- type_in_namespace.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// CHECK:STDOUT: %F.type: type = fn_type @F [concrete]
// CHECK:STDOUT: %F: %F.type = struct_value () [concrete]
// CHECK:STDOUT: %C: type = class_type @C [concrete]
// CHECK:STDOUT: %pattern_type: type = pattern_type %C [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
// CHECK:STDOUT: .c = %c.var
// CHECK:STDOUT: import Cpp//...
// CHECK:STDOUT: }
// CHECK:STDOUT: %c.patt: %pattern_type = ref_binding_pattern c [concrete]
// CHECK:STDOUT: %c.var_patt: %pattern_type = var_pattern %c.patt [concrete]
// CHECK:STDOUT: %c.var: ref %C = var %c.var_patt [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: file {
// CHECK:STDOUT: %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {} {}
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: fn @F() {
// CHECK:STDOUT: !entry:
// CHECK:STDOUT: %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: %c.ref: ref %C = name_ref c, imports.%c.var [concrete = imports.%c.var]
// CHECK:STDOUT: return
// CHECK:STDOUT: }
// CHECK:STDOUT: