[llvm] [LTO] Introduce a new class ImportIDTable (PR #106503)

[Jan Voung via llvm-commits]

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@@ -0,0 +1,79 @@
+//===- ImportIDTableTests.cpp - Unit tests for ImportIDTable --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO/FunctionImport.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include <set>
+#include <type_traits>
+
+using namespace llvm;
+
+TEST(ImportIDTableTests, Basic) {
+  FunctionImporter::ImportIDTable Table;
+
+  auto [Def, Decl] = Table.createImportIDs("mod", 123U);
+  auto [Def2, Decl2] = Table.createImportIDs("stuff", 456U);
+
+  // Def and Decl must be of the same unsigned integer type.
+  static_assert(
+      std::is_unsigned_v<FunctionImporter::ImportIDTable::ImportIDTy>);
+  static_assert(std::is_same_v<FunctionImporter::ImportIDTable::ImportIDTy,
+                               decltype(Def)>);
+  static_assert(std::is_same_v<FunctionImporter::ImportIDTable::ImportIDTy,
+                               decltype(Decl)>);
+
+  // Check that all IDs are unique.
+  std::set<FunctionImporter::ImportIDTable::ImportIDTy> IDs = {Def, Decl, Def2,
+                                                               Decl2};
+  EXPECT_THAT(IDs, ::testing::SizeIs(4));
+
+  // Verify what Def maps to.
+  auto DefTuple = Table.lookup(Def);
+  EXPECT_EQ(std::get<0>(DefTuple), StringRef("mod"));
+  EXPECT_EQ(std::get<1>(DefTuple), 123U);
+  EXPECT_EQ(std::get<2>(DefTuple), GlobalValueSummary::Definition);
+
+  // Verify what Def maps to.
+  auto DeclTuple = Table.lookup(Decl);
+  EXPECT_EQ(std::get<0>(DeclTuple), StringRef("mod"));
+  EXPECT_EQ(std::get<1>(DeclTuple), 123U);
+  EXPECT_EQ(std::get<2>(DeclTuple), GlobalValueSummary::Declaration);
+
+  // Verify what Def2 maps to.
+  auto Def2Tuple = Table.lookup(Def2);
+  EXPECT_EQ(std::get<0>(Def2Tuple), StringRef("stuff"));
+  EXPECT_EQ(std::get<1>(Def2Tuple), 456U);
+  EXPECT_EQ(std::get<2>(Def2Tuple), GlobalValueSummary::Definition);
+
+  // Verify what Def2 maps to.
+  auto Decl2Tuple = Table.lookup(Decl2);
+  EXPECT_EQ(std::get<0>(Decl2Tuple), StringRef("stuff"));
+  EXPECT_EQ(std::get<1>(Decl2Tuple), 456U);
+  EXPECT_EQ(std::get<2>(Decl2Tuple), GlobalValueSummary::Declaration);
----------------
jvoung wrote:

may be good to also do a getImportIds() that returns a present optional (vs the `Missing`) ?

https://github.com/llvm/llvm-project/pull/106503