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Add support for importing C++ namespaces (#5103)

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This adds support for having different C++ `NameScope`s (and not just
the main `Cpp` scope), and we keep a pointer to `clang::DeclContext`
these scopes so we can look up C++ names in the right part of the AST.

C++ Interop Demo with a namespace:

```c++
// hello_world.h

namespace some_namespace {

void hello_world();

}  // namespace some_namespace
```

```c++
// hello_world.cpp

#include <cstdio>

namespace some_namespace {

void hello_world() { printf("Hello World!\n"); }

}  // namespace some_namespace
```

```carbon
// main.carbon

library "Main";

import Cpp library "hello_world.h";

fn Run() -> i32 {
  Cpp.some_namespace.hello_world();
  return 0;
}
```

```shell
$ clang -c hello_world.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link hello_world.o main.o --output=demo
$ ./demo
Hello World!
```

Closes #5102
This commit is contained in:
Boaz Brickner
2025-03-15 20:41:48 +00:00
committed by GitHub
parent fdedbb037d
commit fcd38a4d7f
15 changed files with 585 additions and 88 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/import.cpp
+76 -51
View File
@@ -89,12 +89,53 @@ static auto CopyNameFromImportIR(Context& context,
return import_name_id;
}
// Returns the LocIdandInst for the namespace.
static auto MakeImportedNamespaceLocIdAndInst(Context& context,
SemIR::InstId import_id,
SemIR::Namespace namespace_inst)
-> SemIR::LocIdAndInst {
if (import_id.has_value()) {
SemIR::LocId import_loc_id = context.insts().GetLocId(import_id);
return import_loc_id.is_import_ir_inst_id()
? MakeImportedLocIdAndInst(
context, import_loc_id.import_ir_inst_id(), namespace_inst)
// TODO: Check that this actually is an `AnyNamespaceId`.
: SemIR::LocIdAndInst(
Parse::AnyNamespaceId::UnsafeMake(import_loc_id.node_id()),
namespace_inst);
}
// TODO: Associate the namespace with a proper location. This is related to:
// https://github.com/carbon-language/carbon-lang/issues/4666.
return SemIR::LocIdAndInst::NoLoc(namespace_inst);
}
auto AddImportNamespace(Context& context, SemIR::TypeId namespace_type_id,
SemIR::NameId name_id,
SemIR::NameScopeId parent_scope_id,
bool diagnose_duplicate_namespace,
llvm::function_ref<SemIR::InstId()> make_import_id)
-> AddImportNamespaceResult {
SemIR::InstId import_id) -> AddImportNamespaceResult {
auto namespace_inst =
SemIR::Namespace{.type_id = namespace_type_id,
.name_scope_id = SemIR::NameScopeId::None,
.import_id = import_id};
auto namespace_inst_and_loc =
MakeImportedNamespaceLocIdAndInst(context, import_id, namespace_inst);
AddImportNamespaceResult result = {
.name_scope_id = SemIR::NameScopeId::None,
.inst_id = AddPlaceholderInstInNoBlock(context, namespace_inst_and_loc)};
context.import_ref_ids().push_back(result.inst_id);
namespace_inst.name_scope_id =
context.name_scopes().Add(result.inst_id, name_id, parent_scope_id);
result.name_scope_id = namespace_inst.name_scope_id;
ReplaceInstBeforeConstantUse(context, result.inst_id, namespace_inst);
return result;
}
auto AddImportNamespaceToScope(
Context& context, SemIR::TypeId namespace_type_id, SemIR::NameId name_id,
SemIR::NameScopeId parent_scope_id, bool diagnose_duplicate_namespace,
llvm::function_ref<SemIR::InstId()> make_import_id)
-> AddImportNamespaceToScopeResult {
auto* parent_scope = &context.name_scopes().Get(parent_scope_id);
auto [inserted, entry_id] = parent_scope->LookupOrAdd(
name_id,
@@ -113,8 +154,8 @@ auto AddImportNamespace(Context& context, SemIR::TypeId namespace_type_id,
// id to get more accurate location.
DiagnoseDuplicateName(context, name_id, import_id, prev_inst_id);
}
return {.name_scope_id = namespace_inst->name_scope_id,
.inst_id = prev_inst_id,
return {.add_result = {.name_scope_id = namespace_inst->name_scope_id,
.inst_id = prev_inst_id},
.is_duplicate_of_namespace_in_current_package = true};
}
}
@@ -122,47 +163,29 @@ auto AddImportNamespace(Context& context, SemIR::TypeId namespace_type_id,
auto import_id = make_import_id();
CARBON_CHECK(import_id.has_value());
auto import_loc_id = context.insts().GetLocId(import_id);
auto namespace_inst =
SemIR::Namespace{.type_id = namespace_type_id,
.name_scope_id = SemIR::NameScopeId::None,
.import_id = import_id};
auto namespace_inst_and_loc =
import_loc_id.is_import_ir_inst_id()
? MakeImportedLocIdAndInst(context, import_loc_id.import_ir_inst_id(),
namespace_inst)
// TODO: Check that this actually is an `AnyNamespaceId`.
: SemIR::LocIdAndInst(
Parse::AnyNamespaceId::UnsafeMake(import_loc_id.node_id()),
namespace_inst);
auto namespace_id =
AddPlaceholderInstInNoBlock(context, namespace_inst_and_loc);
context.import_ref_ids().push_back(namespace_id);
namespace_inst.name_scope_id =
context.name_scopes().Add(namespace_id, name_id, parent_scope_id);
ReplaceInstBeforeConstantUse(context, namespace_id, namespace_inst);
AddImportNamespaceToScopeResult result = {
.add_result = AddImportNamespace(context, namespace_type_id, name_id,
parent_scope_id, import_id),
.is_duplicate_of_namespace_in_current_package = false};
// Note we have to get the parent scope freshly, creating the imported
// namespace may invalidate the pointer above.
parent_scope = &context.name_scopes().Get(parent_scope_id);
// Diagnose if there's a name conflict, but still produce the namespace to
// supersede the name conflict in order to avoid repeat diagnostics. Names are
// poisoned optimistically by name lookup before checking for imports, so we
// may be overwriting a poisoned entry here.
auto& result = parent_scope->GetEntry(entry_id).result;
if (!result.is_poisoned() && !inserted) {
// TODO: Pass the import namespace name location instead of the namespace id
// to get more accurate location.
DiagnoseDuplicateName(context, name_id, namespace_id,
result.target_inst_id());
// supersede the name conflict in order to avoid repeat diagnostics. Names
// are poisoned optimistically by name lookup before checking for imports,
// so we may be overwriting a poisoned entry here.
auto& lookup_result = parent_scope->GetEntry(entry_id).result;
if (!lookup_result.is_poisoned() && !inserted) {
// TODO: Pass the import namespace name location instead of the namespace
// id to get more accurate location.
DiagnoseDuplicateName(context, name_id, result.add_result.inst_id,
lookup_result.target_inst_id());
}
result = SemIR::ScopeLookupResult::MakeFound(namespace_id,
SemIR::AccessKind::Public);
return {.name_scope_id = namespace_inst.name_scope_id,
.inst_id = namespace_id,
.is_duplicate_of_namespace_in_current_package = false};
lookup_result = SemIR::ScopeLookupResult::MakeFound(
result.add_result.inst_id, SemIR::AccessKind::Public);
return result;
}
// Adds a copied namespace to the cache.
@@ -185,7 +208,7 @@ static auto CopySingleNameScopeFromImportIR(
Map<SemIR::NameScopeId, SemIR::NameScopeId>* copied_namespaces,
SemIR::ImportIRId ir_id, SemIR::InstId import_inst_id,
SemIR::NameScopeId import_scope_id, SemIR::NameScopeId parent_scope_id,
SemIR::NameId name_id) -> AddImportNamespaceResult {
SemIR::NameId name_id) -> AddImportNamespaceToScopeResult {
// Produce the namespace for the entry.
auto make_import_id = [&]() {
auto entity_name_id = context.entity_names().Add(
@@ -201,17 +224,18 @@ static auto CopySingleNameScopeFromImportIR(
context.import_ref_ids().push_back(inst_id);
return inst_id;
};
AddImportNamespaceResult result = AddImportNamespace(
AddImportNamespaceToScopeResult result = AddImportNamespaceToScope(
context, namespace_type_id, name_id, parent_scope_id,
/*diagnose_duplicate_namespace=*/false, make_import_id);
auto namespace_const_id = context.constant_values().Get(result.inst_id);
auto namespace_const_id =
context.constant_values().Get(result.add_result.inst_id);
context.import_ir_constant_values()[ir_id.index].Set(import_inst_id,
namespace_const_id);
if (copied_namespaces) {
CacheCopiedNamespace(*copied_namespaces, import_scope_id,
result.name_scope_id);
result.add_result.name_scope_id);
}
return result;
}
@@ -261,7 +285,7 @@ static auto CopyAncestorNameScopesFromImportIR(
CopySingleNameScopeFromImportIR(
context, namespace_type_id, &copied_namespaces, ir_id,
import_scope.inst_id(), import_scope_id, scope_cursor, name_id)
.name_scope_id;
.add_result.name_scope_id;
}
return scope_cursor;
@@ -432,7 +456,7 @@ auto ImportApiFile(Context& context, SemIR::TypeId namespace_type_id,
SemIR::ImportIRId::ApiForImpl, todo_scope.api_inst_id,
todo_scope.api_scope_id, todo_scope.impl_parent_scope_id,
todo_scope.impl_name_id)
.name_scope_id;
.add_result.name_scope_id;
ImportScopeFromApiFile(context, api_sem_ir, todo_scope.api_scope_id,
impl_scope_id, todo_scopes);
}
@@ -496,12 +520,13 @@ auto ImportLibrariesFromOtherPackage(Context& context,
auto name_id = SemIR::NameId::ForPackageName(package_id);
AddImportNamespaceResult result = AddImportNamespace(
AddImportNamespaceToScopeResult result = AddImportNamespaceToScope(
context, namespace_type_id, name_id, SemIR::NameScopeId::Package,
/*diagnose_duplicate_namespace=*/true, [&] { return import_decl_id; });
auto namespace_const_id = context.constant_values().Get(result.inst_id);
auto namespace_const_id =
context.constant_values().Get(result.add_result.inst_id);
auto& scope = context.name_scopes().Get(result.name_scope_id);
auto& scope = context.name_scopes().Get(result.add_result.name_scope_id);
scope.set_is_closed_import(
!result.is_duplicate_of_namespace_in_current_package);
for (auto import_ir : import_irs) {
@@ -563,14 +588,14 @@ static auto AddNamespaceFromOtherPackage(Context& context,
-> SemIR::InstId {
auto namespace_type_id =
GetSingletonType(context, SemIR::NamespaceType::SingletonInstId);
AddImportNamespaceResult result = CopySingleNameScopeFromImportIR(
AddImportNamespaceToScopeResult result = CopySingleNameScopeFromImportIR(
context, namespace_type_id, /*copied_namespaces=*/nullptr, import_ir_id,
import_inst_id, import_ns.name_scope_id, parent_scope_id, name_id);
auto& scope = context.name_scopes().Get(result.name_scope_id);
auto& scope = context.name_scopes().Get(result.add_result.name_scope_id);
scope.set_is_closed_import(
!result.is_duplicate_of_namespace_in_current_package);
scope.AddImportIRScope({import_ir_id, import_ns.name_scope_id});
return result.inst_id;
return result.add_result.inst_id;
}
auto ImportNameFromOtherPackage(