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Add support for macros pointing to a constexpr integer (#6441)

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Similarly to the enums, these are for the moment only available when
referenced with a global scope “::”. Only integer constexpr are
available for now.

Part of #6303
This commit is contained in:
Ivana Ivanovska
2025-12-03 15:31:37 +00:00
committed by GitHub
parent a2821be1be
commit 4ddff65e8e
2 changed files with 112 additions and 1 deletions
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toolchain/check/cpp/macros.cpp
+12 -1
View File
@@ -25,7 +25,6 @@ auto TryEvaluateMacroToConstant(Context& context, SemIR::LocId loc_id,
clang::Sema& sema = context.clang_sema();
clang::Preprocessor& preprocessor = sema.getPreprocessor();
clang::Parser parser(preprocessor, sema, false);
llvm::SmallVector<clang::Token> tokens(macro_info->tokens().begin(),
@@ -67,6 +66,8 @@ auto TryEvaluateMacroToConstant(Context& context, SemIR::LocId loc_id,
return nullptr;
}
result_expr = result_expr->IgnoreParenImpCasts();
if (isa<clang::StringLiteral>(result_expr) ||
isa<clang::CharacterLiteral>(result_expr) ||
isa<clang::CXXNullPtrLiteralExpr>(result_expr)) {
@@ -78,6 +79,16 @@ auto TryEvaluateMacroToConstant(Context& context, SemIR::LocId loc_id,
sema.getASTContext()));
clang::APValue ap_value = evaluated_result.Val;
// TODO: Add support for other types.
if (ap_value.isLValue()) {
if (!result_expr->EvaluateAsInt(evaluated_result, sema.getASTContext())) {
context.TODO(loc_id,
"Unsupported: macro evaluated to a non-integer LValue");
return nullptr;
}
ap_value = evaluated_result.Val;
}
switch (ap_value.getKind()) {
case clang::APValue::Int:
if (result_expr->getType()->isBooleanType()) {
toolchain/check/testdata/interop/cpp/macros.carbon
Vendored
+100
View File
@@ -681,6 +681,69 @@ fn F() {
Cpp.M_A_NO_SCOPE;
}
// --- constexpr_int.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr int a = 1;
#define M_CONSTEXPR_INT ::a
''';
fn F() {
//@dump-sem-ir-begin
let a: i32 = Cpp.M_CONSTEXPR_INT;
//@dump-sem-ir-end
}
// --- fail_import_constexpr_no_scope.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr int a = 1;
// CHECK:STDERR: fail_import_constexpr_no_scope.carbon:[[@LINE+7]]:33: error: use of undeclared identifier 'a'; did you mean '::a'? [CppInteropParseError]
// CHECK:STDERR: 13 | #define M_CONSTEXPR_NO_SCOPE a
// CHECK:STDERR: | ^
// CHECK:STDERR: | ::a
// CHECK:STDERR: fail_import_constexpr_no_scope.carbon:[[@LINE-5]]:18: note: '::a' declared here [CppInteropParseNote]
// CHECK:STDERR: 5 | constexpr int a = 1;
// CHECK:STDERR: | ^
#define M_CONSTEXPR_NO_SCOPE a
''';
fn F() {
// CHECK:STDERR: fail_import_constexpr_no_scope.carbon:[[@LINE+4]]:16: note: in `Cpp` name lookup for `M_CONSTEXPR_NO_SCOPE` [InCppNameLookup]
// CHECK:STDERR: let a: i32 = Cpp.M_CONSTEXPR_NO_SCOPE;
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
let a: i32 = Cpp.M_CONSTEXPR_NO_SCOPE;
}
// --- fail_todo_import_macro_constexpr_float.carbon
library "[[@TEST_NAME]]";
import Cpp inline '''
constexpr float b = 1.0f;
#define M_CONSTEXPR_FLOAT ::b
''';
fn F() {
// CHECK:STDERR: fail_todo_import_macro_constexpr_float.carbon:[[@LINE+11]]:16: error: semantics TODO: `Unsupported: macro evaluated to a non-integer LValue` [SemanticsTodo]
// CHECK:STDERR: let a: f32 = Cpp.M_CONSTEXPR_FLOAT;
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR: fail_todo_import_macro_constexpr_float.carbon:[[@LINE+8]]:16: note: in `Cpp` name lookup for `M_CONSTEXPR_FLOAT` [InCppNameLookup]
// CHECK:STDERR: let a: f32 = Cpp.M_CONSTEXPR_FLOAT;
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
// CHECK:STDERR: fail_todo_import_macro_constexpr_float.carbon:[[@LINE+4]]:16: error: member name `M_CONSTEXPR_FLOAT` not found in `Cpp` [MemberNameNotFoundInInstScope]
// CHECK:STDERR: let a: f32 = Cpp.M_CONSTEXPR_FLOAT;
// CHECK:STDERR: ^~~~~~~~~~~~~~~~~~~~~
// CHECK:STDERR:
let a: f32 = Cpp.M_CONSTEXPR_FLOAT;
}
// --- lambda.carbon
library "[[@TEST_NAME]]";
@@ -1828,6 +1891,43 @@ fn F() {
// CHECK:STDOUT: <elided>
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: --- constexpr_int.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {
// 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: %const: type = const_type %i32 [concrete]
// CHECK:STDOUT: %int_1.22e: %const = int_value 1 [concrete]
// CHECK:STDOUT: %int_1.5d2: %i32 = int_value 1 [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: imports {
// CHECK:STDOUT: %Cpp: <namespace> = namespace file.%Cpp.import_cpp, [concrete] {
// CHECK:STDOUT: .M_CONSTEXPR_INT = %int_1
// CHECK:STDOUT: import Cpp//...
// CHECK:STDOUT: }
// CHECK:STDOUT: %int_1: %const = int_value 1 [concrete = constants.%int_1.22e]
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: fn @F() {
// CHECK:STDOUT: !entry:
// CHECK:STDOUT: name_binding_decl {
// CHECK:STDOUT: %a.patt: %pattern_type.7ce = value_binding_pattern a [concrete]
// CHECK:STDOUT: }
// CHECK:STDOUT: %Cpp.ref: <namespace> = name_ref Cpp, imports.%Cpp [concrete = imports.%Cpp]
// CHECK:STDOUT: <elided>
// CHECK:STDOUT: %M_CONSTEXPR_INT.ref: %const = name_ref M_CONSTEXPR_INT, imports.%int_1 [concrete = constants.%int_1.22e]
// CHECK:STDOUT: %.loc11_10: type = splice_block %i32.loc11 [concrete = constants.%i32] {
// CHECK:STDOUT: %int_32.loc11: Core.IntLiteral = int_value 32 [concrete = constants.%int_32]
// CHECK:STDOUT: %i32.loc11: type = class_type @Int, @Int(constants.%int_32) [concrete = constants.%i32]
// CHECK:STDOUT: }
// CHECK:STDOUT: %.loc11_19.1: %i32 = as_compatible %M_CONSTEXPR_INT.ref [concrete = constants.%int_1.5d2]
// CHECK:STDOUT: %.loc11_19.2: %i32 = converted %M_CONSTEXPR_INT.ref, %.loc11_19.1 [concrete = constants.%int_1.5d2]
// CHECK:STDOUT: %a: %i32 = value_binding a, %.loc11_19.2
// CHECK:STDOUT: <elided>
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: --- lambda.carbon
// CHECK:STDOUT:
// CHECK:STDOUT: constants {