[clang] [llvm] [DTLTO] Serialize of LTO Config (PR #219894)

[Konstantin Belochapka via cfe-commits]

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@@ -0,0 +1,181 @@
+//===- LTOConfigBitcodeTest.cpp - LTO config bitcode tests --------------===//
+//
+// 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/LTO/LTOConfigBitcode.h"
+#include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/LTO/TargetOptionsBitcode.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/MemoryBufferRef.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+
+#include <limits>
+
+using namespace llvm;
+using namespace llvm::lto;
+
+TEST(TargetOptionsBitcodeTest, RoundTripThroughBitcode) {
+  TargetOptions Input;
+  Input.MCOptions.BinutilsVersion = {2, 41};
+  Input.FunctionSections = true;
+  Input.DataSections = true;
+  Input.GlobalISelAbort = GlobalISelAbortMode::DisableWithDiag;
+  Input.TLSSize = 64;
+  Input.BBSections = BasicBlockSection::List;
+  Input.BBSectionsFuncListBuf = MemoryBuffer::getMemBufferCopy(
+      "v1\nf foo\nc 0 1\n", "basic-block-sections.profile");
+  Input.EnableDefaultMachineVerifier = false;
+  Input.StackUsageFile = "output.su";
+  Input.LoopAlignment = std::numeric_limits<unsigned>::max();
+  Input.ExceptionModel = ExceptionHandling::Wasm;
+  Input.MCOptions.MCRelaxAll = true;
+  Input.MCOptions.RelocSectionSym = RelocSectionSymType::Internal;
+  Input.MCOptions.DwarfVersion = 5;
+  Input.MCOptions.ABIName = "test-abi";
+  Input.MCOptions.OutputAsmVariant = std::numeric_limits<unsigned>::max();
+  Input.MCOptions.IASSearchPaths = {"include/one", "include/two"};
+  Input.MCOptions.InstPrinterOptions = {"no-aliases"};
+  Input.MCOptions.LargeEHEncoding = true;
+
+  LLVMContext WriteCtx;
+  Module M("target-options", WriteCtx);
+  ASSERT_THAT_ERROR(encodeTargetOptionsToModule(M, Input), Succeeded());
+  EXPECT_TRUE(hasEncodedTargetOptions(M));
+
+  SmallString<0> Storage;
+  raw_svector_ostream OS(Storage);
+  WriteBitcodeToFile(M, OS);
+
+  LLVMContext ReadCtx;
+  Expected<std::unique_ptr<Module>> Parsed = parseBitcodeFile(
+      MemoryBufferRef(StringRef(Storage.data(), Storage.size()), "options.bc"),
+      ReadCtx);
+  ASSERT_THAT_EXPECTED(Parsed, Succeeded());
+  Expected<TargetOptions> Output = decodeTargetOptionsFromModule(**Parsed);
+  ASSERT_THAT_EXPECTED(Output, Succeeded());
+
+  EXPECT_EQ(Output->MCOptions.BinutilsVersion, Input.MCOptions.BinutilsVersion);
+  EXPECT_TRUE(Output->FunctionSections);
+  EXPECT_TRUE(Output->DataSections);
+  EXPECT_EQ(Output->GlobalISelAbort, GlobalISelAbortMode::DisableWithDiag);
----------------
kbelochapka wrote:

Hi @arsenm , Can you please be more specific, what stuff needs to be serialized.
For DTLTO, we are addressing a very specific goal: ensuring that the object file generated from a bitcode file through the ThinLTO pipeline is identical to the object file produced by the DTLTO pipeline. In this context, the FunctionSections and DataSections fields are important because they have a direct impact on the layout and contents of the resulting object file.


https://github.com/llvm/llvm-project/pull/219894