From 2389590230ba886ad21f4136e613bec5bd381ee3 Mon Sep 17 00:00:00 2001 From: Nicholas Bishop Date: Mon, 2 Mar 2026 11:07:23 -0500 Subject: [PATCH] Support pointer template params (#6810) https://github.com/carbon-language/carbon-lang/issues/6717 --- toolchain/check/cpp/call.cpp | 10 +++ toolchain/check/cpp/import.cpp | 22 +++++++ toolchain/check/cpp/import.h | 6 ++ toolchain/check/eval_inst.cpp | 19 +----- .../cpp/template/non_type_param.carbon | 66 ++++++++++++------- 5 files changed, 81 insertions(+), 42 deletions(-) diff --git a/toolchain/check/cpp/call.cpp b/toolchain/check/cpp/call.cpp index ef5b9c2c5e40..8ce6c7335fc1 100644 --- a/toolchain/check/cpp/call.cpp +++ b/toolchain/check/cpp/call.cpp @@ -207,6 +207,16 @@ static auto ConvertArgToTemplateArg( context.ast_context(), param_type, clang::APValue(ap_float)); return clang::TemplateArgumentLoc(template_arg, template_loc); } + } else if (param_type->isPointerType()) { + if (auto addr_of = + context.insts().TryGetAs(const_inst_id)) { + if (auto* var_decl = GetAsClangVarDecl(context, addr_of->lvalue_id)) { + clang::TemplateArgument template_arg(var_decl, param_type); + return clang::TemplateArgumentLoc(template_arg, template_loc); + } + + // TODO: support pointers to variables declared in Carbon. + } } } diff --git a/toolchain/check/cpp/import.cpp b/toolchain/check/cpp/import.cpp index 61512e80e15f..e7abf2310c5f 100644 --- a/toolchain/check/cpp/import.cpp +++ b/toolchain/check/cpp/import.cpp @@ -63,6 +63,7 @@ #include "toolchain/sem_ir/ids.h" #include "toolchain/sem_ir/inst.h" #include "toolchain/sem_ir/name_scope.h" +#include "toolchain/sem_ir/pattern.h" #include "toolchain/sem_ir/typed_insts.h" namespace Carbon::Check { @@ -2312,4 +2313,25 @@ auto ImportClassDefinitionForClangDecl(Context& context, return true; } +auto GetAsClangVarDecl(Context& context, SemIR::InstId inst_id) + -> clang::VarDecl* { + if (const auto& var_storage = + context.insts().TryGetAs(inst_id)) { + auto var_name_id = SemIR::GetFirstBindingNameFromPatternId( + context.sem_ir(), var_storage->pattern_id); + if (auto cpp_global_var_id = context.sem_ir().cpp_global_vars().Lookup( + {.entity_name_id = var_name_id}); + cpp_global_var_id.has_value()) { + SemIR::ClangDeclId clang_decl_id = context.sem_ir() + .cpp_global_vars() + .Get(cpp_global_var_id) + .clang_decl_id; + return cast( + context.clang_decls().Get(clang_decl_id).key.decl); + } + } + + return nullptr; +} + } // namespace Carbon::Check diff --git a/toolchain/check/cpp/import.h b/toolchain/check/cpp/import.h index 34ff05936d74..935659a6cbc6 100644 --- a/toolchain/check/cpp/import.h +++ b/toolchain/check/cpp/import.h @@ -81,6 +81,12 @@ auto ImportClassDefinitionForClangDecl(Context& context, auto GetClangIdentifierInfo(Context& context, SemIR::NameId name_id) -> clang::IdentifierInfo*; +// Maps from a `VarStorage` instruction to a `clang::VarDecl`. Returns +// null if the instruction is not a `VarStorage`, or if its contents +// cannot be mapped to a `clang::VarDecl`. +auto GetAsClangVarDecl(Context& context, SemIR::InstId inst_id) + -> clang::VarDecl*; + } // namespace Carbon::Check #endif // CARBON_TOOLCHAIN_CHECK_CPP_IMPORT_H_ diff --git a/toolchain/check/eval_inst.cpp b/toolchain/check/eval_inst.cpp index 832f4de65cd1..d2a465349a73 100644 --- a/toolchain/check/eval_inst.cpp +++ b/toolchain/check/eval_inst.cpp @@ -9,6 +9,7 @@ #include "toolchain/base/kind_switch.h" #include "toolchain/check/action.h" #include "toolchain/check/cpp/constant.h" +#include "toolchain/check/cpp/import.h" #include "toolchain/check/cpp/type_mapping.h" #include "toolchain/check/diagnostic_helpers.h" #include "toolchain/check/facet_type.h" @@ -126,23 +127,7 @@ auto EvalConstantInst(Context& /*context*/, SemIR::ValueBinding /*inst*/) auto EvalConstantInst(Context& context, SemIR::InstId inst_id, SemIR::AcquireValue inst) -> ConstantEvalResult { - const auto& var_storage = - context.insts().TryGetAs(inst.value_id); - if (!var_storage) { - return ConstantEvalResult::NotConstant; - } - - // Try to map from var storage to a C++ global. - auto var_name_id = SemIR::GetFirstBindingNameFromPatternId( - context.sem_ir(), var_storage->pattern_id); - if (auto cpp_global_var_id = context.sem_ir().cpp_global_vars().Lookup( - {.entity_name_id = var_name_id}); - cpp_global_var_id.has_value()) { - SemIR::ClangDeclId clang_decl_id = - context.sem_ir().cpp_global_vars().Get(cpp_global_var_id).clang_decl_id; - const auto* var_decl = - cast(context.clang_decls().Get(clang_decl_id).key.decl); - + if (const auto* var_decl = GetAsClangVarDecl(context, inst.value_id)) { // If the C++ global is constant, map it to a Carbon constant. if (var_decl->isUsableInConstantExpressions(context.ast_context())) { if (const auto* ap_value = var_decl->getEvaluatedValue()) { diff --git a/toolchain/check/testdata/interop/cpp/template/non_type_param.carbon b/toolchain/check/testdata/interop/cpp/template/non_type_param.carbon index 79d2dd4521b8..98eb68f31229 100644 --- a/toolchain/check/testdata/interop/cpp/template/non_type_param.carbon +++ b/toolchain/check/testdata/interop/cpp/template/non_type_param.carbon @@ -25,6 +25,8 @@ DependentNonType MakeDependentNonType123() { return DependentNonType(); } +static int StaticInt = 789; + // --- valid_int_param.carbon library "[[@TEST_NAME]]"; @@ -97,6 +99,18 @@ Struct<123.5f> MakeStruct() { return Struct<123.5f>(); } '''; let v: Cpp.Struct(123.5) = Cpp.MakeStruct(); +// --- pointer.carbon + +library "[[@TEST_NAME]]"; + +import Cpp inline ''' +template struct Struct {}; +static int i = 123; +Struct<&i> MakeStruct() { return Struct<&i>(); } +'''; + +let xyz: Cpp.Struct(&Cpp.i) = Cpp.MakeStruct(); + // --- valid.carbon library "[[@TEST_NAME]]"; @@ -107,22 +121,15 @@ import Cpp library "templates.h"; var x: Cpp.TwoNonType(1, 2); //@dump-sem-ir-end -// --- fail_todo_dependent.carbon +// --- dependent.carbon library "[[@TEST_NAME]]"; import Cpp library "templates.h"; -var n: i32; - //@dump-sem-ir-begin var x: Cpp.DependentNonType(i32, 123) = Cpp.MakeDependentNonType123(); - -// CHECK:STDERR: fail_todo_dependent.carbon:[[@LINE+4]]:35: error: semantics TODO: `unsupported argument type for non-type template parameter` [SemanticsTodo] -// CHECK:STDERR: var y: Cpp.DependentNonType(i32*, &n); -// CHECK:STDERR: ^~ -// CHECK:STDERR: -var y: Cpp.DependentNonType(i32*, &n); +var y: Cpp.DependentNonType(i32*, &Cpp.StaticInt); //@dump-sem-ir-end // --- fail_type_argument.carbon @@ -173,25 +180,31 @@ var x: Cpp.TwoNonType(1, &n); // CHECK:STDOUT: %x: ref %TwoNonType = ref_binding x, %x.var [concrete = %x.var] // CHECK:STDOUT: } // CHECK:STDOUT: -// CHECK:STDOUT: --- fail_todo_dependent.carbon +// CHECK:STDOUT: --- dependent.carbon // CHECK:STDOUT: // CHECK:STDOUT: constants { // CHECK:STDOUT: %empty_tuple.type: type = tuple_type () [concrete] // CHECK:STDOUT: %DependentNonType.type: type = cpp_type_template_type DependentNonType [concrete] // CHECK:STDOUT: %DependentNonType.template: %DependentNonType.type = struct_value () [concrete] -// CHECK:STDOUT: %DependentNonType: type = class_type @DependentNonType [concrete] -// CHECK:STDOUT: %pattern_type.b95: type = pattern_type %DependentNonType [concrete] +// CHECK:STDOUT: %int_32: Core.IntLiteral = int_value 32 [concrete] +// CHECK:STDOUT: %i32: type = class_type @Int, @Int(%int_32) [concrete] +// CHECK:STDOUT: %pattern_type.7ce: type = pattern_type %i32 [concrete] +// CHECK:STDOUT: %DependentNonType.794fcf.1: type = class_type @DependentNonType.1 [concrete] +// CHECK:STDOUT: %pattern_type.b95a71.1: type = pattern_type %DependentNonType.794fcf.1 [concrete] // CHECK:STDOUT: %MakeDependentNonType123.cpp_overload_set.type: type = cpp_overload_set_type @MakeDependentNonType123.cpp_overload_set [concrete] // CHECK:STDOUT: %MakeDependentNonType123.cpp_overload_set.value: %MakeDependentNonType123.cpp_overload_set.type = cpp_overload_set_value @MakeDependentNonType123.cpp_overload_set [concrete] -// CHECK:STDOUT: %ptr.5b4: type = ptr_type %DependentNonType [concrete] +// CHECK:STDOUT: %ptr.5b4: type = ptr_type %DependentNonType.794fcf.1 [concrete] // CHECK:STDOUT: %MakeDependentNonType123__carbon_thunk.type: type = fn_type @MakeDependentNonType123__carbon_thunk [concrete] // CHECK:STDOUT: %MakeDependentNonType123__carbon_thunk: %MakeDependentNonType123__carbon_thunk.type = struct_value () [concrete] +// CHECK:STDOUT: %DependentNonType.794fcf.2: type = class_type @DependentNonType.2 [concrete] +// CHECK:STDOUT: %pattern_type.b95a71.2: type = pattern_type %DependentNonType.794fcf.2 [concrete] // CHECK:STDOUT: } // CHECK:STDOUT: // CHECK:STDOUT: imports { // CHECK:STDOUT: %Cpp: = namespace file.%Cpp.import_cpp, [concrete] { // CHECK:STDOUT: .DependentNonType = %DependentNonType.template // CHECK:STDOUT: .MakeDependentNonType123 = %MakeDependentNonType123.cpp_overload_set.value +// CHECK:STDOUT: .StaticInt = %StaticInt.var // CHECK:STDOUT: import Cpp//... // CHECK:STDOUT: } // CHECK:STDOUT: %DependentNonType.template: %DependentNonType.type = struct_value () [concrete = constants.%DependentNonType.template] @@ -201,32 +214,35 @@ var x: Cpp.TwoNonType(1, &n); // CHECK:STDOUT: } { // CHECK:STDOUT: // CHECK:STDOUT: } +// CHECK:STDOUT: %StaticInt.patt: %pattern_type.7ce = ref_binding_pattern StaticInt [concrete] +// CHECK:STDOUT: %StaticInt.var_patt: %pattern_type.7ce = var_pattern %StaticInt.patt [concrete] +// CHECK:STDOUT: %StaticInt.var: ref %i32 = var %StaticInt.var_patt [concrete] // CHECK:STDOUT: } // CHECK:STDOUT: // CHECK:STDOUT: file { // CHECK:STDOUT: name_binding_decl { -// CHECK:STDOUT: %x.patt: %pattern_type.b95 = ref_binding_pattern x [concrete] -// CHECK:STDOUT: %x.var_patt: %pattern_type.b95 = var_pattern %x.patt [concrete] +// CHECK:STDOUT: %x.patt: %pattern_type.b95a71.1 = ref_binding_pattern x [concrete] +// CHECK:STDOUT: %x.var_patt: %pattern_type.b95a71.1 = var_pattern %x.patt [concrete] // CHECK:STDOUT: } -// CHECK:STDOUT: %x.var: ref %DependentNonType = var %x.var_patt [concrete] -// CHECK:STDOUT: %x: ref %DependentNonType = ref_binding x, %x.var [concrete = %x.var] +// CHECK:STDOUT: %x.var: ref %DependentNonType.794fcf.1 = var %x.var_patt [concrete] +// CHECK:STDOUT: %x: ref %DependentNonType.794fcf.1 = ref_binding x, %x.var [concrete = %x.var] // CHECK:STDOUT: name_binding_decl { -// CHECK:STDOUT: %y.patt: = ref_binding_pattern y [concrete] -// CHECK:STDOUT: %y.var_patt: = var_pattern %y.patt [concrete] +// CHECK:STDOUT: %y.patt: %pattern_type.b95a71.2 = ref_binding_pattern y [concrete] +// CHECK:STDOUT: %y.var_patt: %pattern_type.b95a71.2 = var_pattern %y.patt [concrete] // CHECK:STDOUT: } -// CHECK:STDOUT: %y.var: ref = var %y.var_patt [concrete = ] -// CHECK:STDOUT: %y: ref = ref_binding y, [concrete = ] +// CHECK:STDOUT: %y.var: ref %DependentNonType.794fcf.2 = var %y.var_patt [concrete] +// CHECK:STDOUT: %y: ref %DependentNonType.794fcf.2 = ref_binding y, %y.var [concrete = %y.var] // CHECK:STDOUT: } // CHECK:STDOUT: // CHECK:STDOUT: fn @__global_init() { // CHECK:STDOUT: !entry: // CHECK:STDOUT: %Cpp.ref: = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp] // CHECK:STDOUT: %MakeDependentNonType123.ref: %MakeDependentNonType123.cpp_overload_set.type = name_ref MakeDependentNonType123, imports.%MakeDependentNonType123.cpp_overload_set.value [concrete = constants.%MakeDependentNonType123.cpp_overload_set.value] -// CHECK:STDOUT: %.loc9_1: ref %DependentNonType = splice_block file.%x.var [concrete = file.%x.var] {} -// CHECK:STDOUT: %addr: %ptr.5b4 = addr_of %.loc9_1 +// CHECK:STDOUT: %.loc7_1: ref %DependentNonType.794fcf.1 = splice_block file.%x.var [concrete = file.%x.var] {} +// CHECK:STDOUT: %addr: %ptr.5b4 = addr_of %.loc7_1 // CHECK:STDOUT: %MakeDependentNonType123__carbon_thunk.call: init %empty_tuple.type = call imports.%MakeDependentNonType123__carbon_thunk.decl(%addr) -// CHECK:STDOUT: %.loc9_69: init %DependentNonType to %.loc9_1 = mark_in_place_init %MakeDependentNonType123__carbon_thunk.call -// CHECK:STDOUT: assign file.%x.var, %.loc9_69 +// CHECK:STDOUT: %.loc7_69: init %DependentNonType.794fcf.1 to %.loc7_1 = mark_in_place_init %MakeDependentNonType123__carbon_thunk.call +// CHECK:STDOUT: assign file.%x.var, %.loc7_69 // CHECK:STDOUT: // CHECK:STDOUT: } // CHECK:STDOUT: