Add PerformCallToCppFunction() which calls simplified version of PerformCppOverloadResolution() before calling PerformCallToFunction() (#6122)

Instead of calling `PerformCppOverloadResolution()` and use the complex return value to call `PerformCallToFunction()`, we call `PerformCallToCppFunction()` which will call both `PerformCppOverloadResolution()` and `PerformCallToFunction()`. Followup of #6112. Part of #5995.
2026-10-04 19:01:05 +01:00 · 2025-09-29 14:26:23 +00:00
parent 3b6d202730
commit 5705b94da8
9 changed files with 135 additions and 107 deletions
@@ -0,0 +1,59 @@
+// 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 "toolchain/check/cpp/call.h"
+
+#include "toolchain/base/kind_switch.h"
+#include "toolchain/check/call.h"
+#include "toolchain/check/cpp/operators.h"
+#include "toolchain/check/cpp/overload_resolution.h"
+#include "toolchain/sem_ir/function.h"
+#include "toolchain/sem_ir/ids.h"
+#include "toolchain/sem_ir/typed_insts.h"
+
+namespace Carbon::Check {
+
+// Returns whether the function is an imported C++ operator member function.
+static auto IsCppOperatorMethod(Context& context, SemIR::FunctionId function_id)
+    -> bool {
+  SemIR::ClangDeclId clang_decl_id =
+      context.functions().Get(function_id).clang_decl_id;
+  return clang_decl_id.has_value() &&
+         IsCppOperatorMethodDecl(
+             context.clang_decls().Get(clang_decl_id).key.decl);
+}
+
+auto PerformCallToCppFunction(Context& context, SemIR::LocId loc_id,
+                              SemIR::CppOverloadSetId overload_set_id,
+                              SemIR::InstId self_id,
+                              llvm::ArrayRef<SemIR::InstId> arg_ids)
+    -> SemIR::InstId {
+  SemIR::InstId callee_id = PerformCppOverloadResolution(
+      context, loc_id, overload_set_id, self_id, arg_ids);
+  SemIR::Callee callee = GetCallee(context.sem_ir(), callee_id);
+  CARBON_KIND_SWITCH(callee) {
+    case CARBON_KIND(SemIR::CalleeError _): {
+      return SemIR::ErrorInst::InstId;
+    }
+    case CARBON_KIND(SemIR::CalleeFunction fn): {
+      CARBON_CHECK(!fn.self_id.has_value());
+      if (self_id.has_value()) {
+        // Preserve the `self` argument from the original callee.
+        fn.self_id = self_id;
+      } else if (IsCppOperatorMethod(context, fn.function_id)) {
+        // Adjust `self` and args for C++ overloaded operator methods.
+        fn.self_id = arg_ids.consume_front();
+      }
+      return PerformCallToFunction(context, loc_id, callee_id, fn, arg_ids);
+    }
+    case CARBON_KIND(SemIR::CalleeCppOverloadSet _): {
+      CARBON_FATAL("overloads can't be recursive");
+    }
+    case CARBON_KIND(SemIR::CalleeNonFunction _): {
+      CARBON_FATAL("overloads should produce functions");
+    }
+  }
+}
+
+}  // namespace Carbon::Check