[llvm] [AArch64][TargetParser] Add ProcessorAlias unit test machinery. NFC. (PR #127131)

[Ahmed Bougacha via llvm-commits]

https://github.com/ahmedbougacha created https://github.com/llvm/llvm-project/pull/127131

The patch itself is mainly the expected unittest boilerplate.
This adds tests for the aliases we have today.

We could alternatively test these via the driver with additional run-lines in print-enable-extensions tests, and eventually should consider that instead.

>From 6a7c755d676321e7c07f6a6322c22a9ec1a170eb Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Thu, 13 Feb 2025 13:53:21 -0800
Subject: [PATCH] [AArch64][TargetParser] Add ProcessorAlias unit test
 machinery. NFC.

The patch itself is mainly the expected unittest boilerplate.
This adds tests for the aliases we have today.

We could alternatively test these via the driver with additional
run-lines in print-enable-extensions tests, and eventually should
consider that instead.
---
 .../TargetParser/TargetParserTest.cpp         | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/llvm/unittests/TargetParser/TargetParserTest.cpp b/llvm/unittests/TargetParser/TargetParserTest.cpp
index 11d552bfa328b..7fee62721e6e0 100644
--- a/llvm/unittests/TargetParser/TargetParserTest.cpp
+++ b/llvm/unittests/TargetParser/TargetParserTest.cpp
@@ -1165,6 +1165,92 @@ INSTANTIATE_TEST_SUITE_P(
                       AArch64CPUTestParams("oryon-1", "armv8.6-a")),
     AArch64CPUTestParams::PrintToStringParamName);
 
+struct AArch64CPUAliasTestParams {
+  AArch64CPUAliasTestParams(std::vector<StringRef> Aliases)
+      : Aliases(Aliases) {}
+
+  friend std::ostream &operator<<(std::ostream &os,
+                                  const AArch64CPUAliasTestParams &params) {
+    raw_os_ostream oss(os);
+    interleave(params.Aliases, oss, ", ");
+    return os;
+  }
+
+  /// Print a gtest-compatible facsimile of the first cpu (the aliasee), to make
+  /// the test's name human-readable.
+  static std::string PrintToStringParamName(
+      const testing::TestParamInfo<AArch64CPUAliasTestParams> &Info) {
+    std::string Name = Info.param.Aliases.front().str();
+    for (char &C : Name)
+      if (!std::isalnum(C))
+        C = '_';
+    return Name;
+  }
+
+  std::vector<StringRef> Aliases;
+};
+
+class AArch64CPUAliasTestFixture
+    : public ::testing::TestWithParam<AArch64CPUAliasTestParams> {};
+
+static std::string aarch64FeaturesFromBits(AArch64::ExtensionBitset BitFlags) {
+  std::vector<StringRef> Flags;
+  bool OK = AArch64::getExtensionFeatures(BitFlags, Flags);
+  assert(OK);
+  (void)OK;
+  std::string S;
+  raw_string_ostream OS(S);
+  interleave(Flags, OS, ", ");
+  return OS.str();
+}
+
+TEST_P(AArch64CPUAliasTestFixture, testCPUAlias) {
+  AArch64CPUAliasTestParams params = GetParam();
+
+  StringRef MainName = params.Aliases[0];
+  const std::optional<AArch64::CpuInfo> Cpu = AArch64::parseCpu(MainName);
+  const AArch64::ArchInfo &MainAI = Cpu->Arch;
+  AArch64::ExtensionBitset MainFlags = Cpu->getImpliedExtensions();
+
+  for (size_t I = 1, E = params.Aliases.size(); I != E; ++I) {
+    StringRef OtherName = params.Aliases[I];
+    const std::optional<AArch64::CpuInfo> OtherCpu =
+        AArch64::parseCpu(OtherName);
+    const AArch64::ArchInfo &OtherAI = OtherCpu->Arch;
+
+    EXPECT_EQ(MainAI.Version, OtherAI.Version)
+        << MainName << " vs " << OtherName;
+    EXPECT_EQ(MainAI.Name, OtherAI.Name) << MainName << " vs " << OtherName;
+    EXPECT_EQ(MainAI.Profile, OtherAI.Profile)
+        << MainName << " vs " << OtherName;
+    EXPECT_EQ(MainAI.DefaultExts, OtherAI.DefaultExts)
+        << MainName << " vs " << OtherName;
+    EXPECT_EQ(MainAI, OtherAI) << MainName << " vs " << OtherName;
+
+    AArch64::ExtensionBitset OtherFlags = OtherCpu->getImpliedExtensions();
+
+    EXPECT_EQ(MainFlags, OtherFlags) << MainName << " vs " << OtherName;
+
+    EXPECT_EQ(aarch64FeaturesFromBits(MainFlags),
+              aarch64FeaturesFromBits(OtherFlags))
+        << MainName << " vs " << OtherName << "\n        Diff: "
+        << (aarch64FeaturesFromBits(MainFlags ^ OtherFlags));
+  }
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    AArch64CPUAliasTests, AArch64CPUAliasTestFixture,
+    ::testing::Values(AArch64CPUAliasTestParams({"neoverse-n2", "cobalt-100"}),
+                      AArch64CPUAliasTestParams({"neoverse-v2", "grace"}),
+                      AArch64CPUAliasTestParams({"apple-a7", "cyclone",
+                                                 "apple-a8", "apple-a9"}),
+                      AArch64CPUAliasTestParams({"apple-a12", "apple-s4",
+                                                 "apple-s5"}),
+                      AArch64CPUAliasTestParams({"apple-a14", "apple-m1"}),
+                      AArch64CPUAliasTestParams({"apple-a15", "apple-m2"}),
+                      AArch64CPUAliasTestParams({"apple-a16", "apple-m3"})),
+    AArch64CPUAliasTestParams::PrintToStringParamName);
+
 // Note: number of CPUs includes aliases.
 static constexpr unsigned NumAArch64CPUArchs = 82;