[llvm] [CodeGen] Allow `CodeGenPassBuilder` to add module pass after function pass (PR #77084)

[via llvm-commits]

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@@ -0,0 +1,158 @@
+//===- llvm/unittest/CodeGen/CodeGenPassBuilderTest.cpp -------------------===//
+//
+// 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/CodeGen/CodeGenPassBuilder.h"
+#include "llvm/CodeGen/MachinePassManager.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/TargetParser/Host.h"
+#include "gtest/gtest.h"
+#include <string>
+
+using namespace llvm;
+
+namespace {
+
+struct NoOpModulePass : PassInfoMixin<NoOpModulePass> {
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &) {
+    return PreservedAnalyses::all();
+  }
+
+  static StringRef name() { return "NoOpModulePass"; }
+};
+
+struct NoOpFunctionPass : PassInfoMixin<NoOpFunctionPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &) {
+    return PreservedAnalyses::all();
+  }
+  static StringRef name() { return "NoOpFunctionPass"; }
+};
+
+class DummyCodeGenPassBuilder
+    : public CodeGenPassBuilder<DummyCodeGenPassBuilder> {
+public:
+  DummyCodeGenPassBuilder(LLVMTargetMachine &TM, CGPassBuilderOption Opts,
+                          PassInstrumentationCallbacks *PIC)
+      : CodeGenPassBuilder(TM, Opts, PIC){};
+
+  void addPreISel(AddIRPass &addPass) const {
+    addPass(NoOpModulePass());
+    addPass(NoOpFunctionPass());
+    addPass(NoOpFunctionPass());
+    addPass(NoOpFunctionPass());
+    addPass(NoOpModulePass());
+    addPass(NoOpFunctionPass());
+  }
+
+  void addAsmPrinter(AddMachinePass &, CreateMCStreamer) const {}
+
+  Error addInstSelector(AddMachinePass &) const { return Error::success(); }
+};
+
+class CodeGenPassBuilderTest : public testing::Test {
+public:
+  LLVMTargetMachine *TM;
+
+  static void SetUpTestCase() {
+    InitializeAllTargets();
+    InitializeAllTargetMCs();
+
+    static const char *argv[] = {
+        "test",
+        "-print-pipeline-passes",
+    };
+    int argc = std::size(argv);
+    cl::ParseCommandLineOptions(argc, argv);
+  }
+
+  void SetUp() override {
+    std::string TripleName = Triple::normalize(sys::getDefaultTargetTriple());
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paperchalice wrote:

> Would be slightly safer to just pick a target machine and go with it, and disable the test if the target's not built

Pick the default target machine and skip test when default target is not built now.

https://github.com/llvm/llvm-project/pull/77084