lib/Frontend/CompilerInstance.cpp - llvm-project/flang - Git at Google

 //===--- CompilerInstance.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
 //
 //===----------------------------------------------------------------------===//
 //
 // Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
 //
 //===----------------------------------------------------------------------===//

 #include "flang/Frontend/CompilerInstance.h"
 #include "flang/Common/Fortran-features.h"
 #include "flang/Frontend/CompilerInvocation.h"
 #include "flang/Frontend/TextDiagnosticPrinter.h"
 #include "flang/Parser/parsing.h"
 #include "flang/Parser/provenance.h"
 #include "flang/Semantics/semantics.h"
 #include "clang/Basic/DiagnosticFrontend.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/TargetParser.h"
 #include "llvm/TargetParser/Triple.h"

 using namespace Fortran::frontend;

 CompilerInstance::CompilerInstance()
     : invocation(new CompilerInvocation()),
       allSources(new Fortran::parser::AllSources()),
       allCookedSources(new Fortran::parser::AllCookedSources(*allSources)),
       parsing(new Fortran::parser::Parsing(*allCookedSources)) {
   // TODO: This is a good default during development, but ultimately we should
   // give the user the opportunity to specify this.
   allSources->set_encoding(Fortran::parser::Encoding::UTF_8);
 }

 CompilerInstance::~CompilerInstance() {
   assert(outputFiles.empty() && "Still output files in flight?");
 }

 void CompilerInstance::setInvocation(
     std::shared_ptr<CompilerInvocation> value) {
   invocation = std::move(value);
 }

 void CompilerInstance::setSemaOutputStream(raw_ostream &value) {
   ownedSemaOutputStream.release();
   semaOutputStream = &value;
 }

 void CompilerInstance::setSemaOutputStream(std::unique_ptr<raw_ostream> value) {
   ownedSemaOutputStream.swap(value);
   semaOutputStream = ownedSemaOutputStream.get();
 }

 // Helper method to generate the path of the output file. The following logic
 // applies:
 // 1. If the user specifies the output file via `-o`, then use that (i.e.
 //    the outputFilename parameter).
 // 2. If the user does not specify the name of the output file, derive it from
 //    the input file (i.e. inputFilename + extension)
 // 3. If the output file is not specified and the input file is `-`, then set
 //    the output file to `-` as well.
 static std::string getOutputFilePath(llvm::StringRef outputFilename,
                                      llvm::StringRef inputFilename,
                                      llvm::StringRef extension) {

   // Output filename _is_ specified. Just use that.
   if (!outputFilename.empty())
     return std::string(outputFilename);

   // Output filename _is not_ specified. Derive it from the input file name.
   std::string outFile = "-";
   if (!extension.empty() && (inputFilename != "-")) {
     llvm::SmallString<128> path(inputFilename);
     llvm::sys::path::replace_extension(path, extension);
     outFile = std::string(path);
   }

   return outFile;
 }

 std::unique_ptr<llvm::raw_pwrite_stream>
 CompilerInstance::createDefaultOutputFile(bool binary, llvm::StringRef baseName,
                                           llvm::StringRef extension) {

   // Get the path of the output file
   std::string outputFilePath =
       getOutputFilePath(getFrontendOpts().outputFile, baseName, extension);

   // Create the output file
   llvm::Expected<std::unique_ptr<llvm::raw_pwrite_stream>> os =
       createOutputFileImpl(outputFilePath, binary);

   // If successful, add the file to the list of tracked output files and
   // return.
   if (os) {
     outputFiles.emplace_back(OutputFile(outputFilePath));
     return std::move(*os);
   }

   // If unsuccessful, issue an error and return Null
   unsigned diagID = getDiagnostics().getCustomDiagID(
       clang::DiagnosticsEngine::Error, "unable to open output file '%0': '%1'");
   getDiagnostics().Report(diagID)
       << outputFilePath << llvm::errorToErrorCode(os.takeError()).message();
   return nullptr;
 }

 llvm::Expected<std::unique_ptr<llvm::raw_pwrite_stream>>
 CompilerInstance::createOutputFileImpl(llvm::StringRef outputFilePath,
                                        bool binary) {

   // Creates the file descriptor for the output file
   std::unique_ptr<llvm::raw_fd_ostream> os;

   std::error_code error;
   os.reset(new llvm::raw_fd_ostream(
       outputFilePath, error,
       (binary ? llvm::sys::fs::OF_None : llvm::sys::fs::OF_TextWithCRLF)));
   if (error) {
     return llvm::errorCodeToError(error);
   }

   // For seekable streams, just return the stream corresponding to the output
   // file.
   if (!binary || os->supportsSeeking())
     return std::move(os);

   // For non-seekable streams, we need to wrap the output stream into something
   // that supports 'pwrite' and takes care of the ownership for us.
   return std::make_unique<llvm::buffer_unique_ostream>(std::move(os));
 }

 void CompilerInstance::clearOutputFiles(bool eraseFiles) {
   for (OutputFile &of : outputFiles)
     if (!of.filename.empty() && eraseFiles)
       llvm::sys::fs::remove(of.filename);

   outputFiles.clear();
 }

 bool CompilerInstance::executeAction(FrontendAction &act) {
   auto &invoc = this->getInvocation();

   llvm::Triple targetTriple{llvm::Triple(invoc.getTargetOpts().triple)};
   if (targetTriple.getArch() == llvm::Triple::ArchType::x86_64) {
     invoc.getDefaultKinds().set_quadPrecisionKind(10);
   }

   // Set some sane defaults for the frontend.
   invoc.setDefaultFortranOpts();
   // Update the fortran options based on user-based input.
   invoc.setFortranOpts();
   // Set the encoding to read all input files in based on user input.
   allSources->set_encoding(invoc.getFortranOpts().encoding);
   if (!setUpTargetMachine())
     return false;
   // Create the semantics context
   semaContext = invoc.getSemanticsCtx(*allCookedSources, getTargetMachine());
   // Set options controlling lowering to FIR.
   invoc.setLoweringOptions();

   // Run the frontend action `act` for every input file.
   for (const FrontendInputFile &fif : getFrontendOpts().inputs) {
     if (act.beginSourceFile(*this, fif)) {
       if (llvm::Error err = act.execute()) {
         consumeError(std::move(err));
       }
       act.endSourceFile();
     }
   }
   return !getDiagnostics().getClient()->getNumErrors();
 }

 void CompilerInstance::createDiagnostics(clang::DiagnosticConsumer *client,
                                          bool shouldOwnClient) {
   diagnostics =
       createDiagnostics(&getDiagnosticOpts(), client, shouldOwnClient);
 }

 clang::IntrusiveRefCntPtr<clang::DiagnosticsEngine>
 CompilerInstance::createDiagnostics(clang::DiagnosticOptions *opts,
                                     clang::DiagnosticConsumer *client,
                                     bool shouldOwnClient) {
   clang::IntrusiveRefCntPtr<clang::DiagnosticIDs> diagID(
       new clang::DiagnosticIDs());
   clang::IntrusiveRefCntPtr<clang::DiagnosticsEngine> diags(
       new clang::DiagnosticsEngine(diagID, opts));

   // Create the diagnostic client for reporting errors or for
   // implementing -verify.
   if (client) {
     diags->setClient(client, shouldOwnClient);
   } else {
     diags->setClient(new TextDiagnosticPrinter(llvm::errs(), opts));
   }
   return diags;
 }

 // Get feature string which represents combined explicit target features
 // for AMD GPU and the target features specified by the user
 static std::string
 getExplicitAndImplicitAMDGPUTargetFeatures(clang::DiagnosticsEngine &diags,
                                            const TargetOptions &targetOpts,
                                            const llvm::Triple triple) {
   llvm::StringRef cpu = targetOpts.cpu;
   llvm::StringMap<bool> implicitFeaturesMap;
   std::string errorMsg;
   // Get the set of implicit target features
   llvm::AMDGPU::fillAMDGPUFeatureMap(cpu, triple, implicitFeaturesMap);

   // Add target features specified by the user
   for (auto &userFeature : targetOpts.featuresAsWritten) {
     std::string userKeyString = userFeature.substr(1);
     implicitFeaturesMap[userKeyString] = (userFeature[0] == '+');
   }

   if (!llvm::AMDGPU::insertWaveSizeFeature(cpu, triple, implicitFeaturesMap,
                                            errorMsg)) {
     unsigned diagID = diags.getCustomDiagID(clang::DiagnosticsEngine::Error,
                                             "Unsupported feature ID: %0");
     diags.Report(diagID) << errorMsg.data();
     return std::string();
   }

   llvm::SmallVector<std::string> featuresVec;
   for (auto &implicitFeatureItem : implicitFeaturesMap) {
     featuresVec.push_back((llvm::Twine(implicitFeatureItem.second ? "+" : "-") +
                            implicitFeatureItem.first().str())
                               .str());
   }
   llvm::sort(featuresVec);
   return llvm::join(featuresVec, ",");
 }

 // Get feature string which represents combined explicit target features
 // for NVPTX and the target features specified by the user/
 // TODO: Have a more robust target conf like `clang/lib/Basic/Targets/NVPTX.cpp`
 static std::string
 getExplicitAndImplicitNVPTXTargetFeatures(clang::DiagnosticsEngine &diags,
                                           const TargetOptions &targetOpts,
                                           const llvm::Triple triple) {
   llvm::StringRef cpu = targetOpts.cpu;
   llvm::StringMap<bool> implicitFeaturesMap;
   std::string errorMsg;
   bool ptxVer = false;

   // Add target features specified by the user
   for (auto &userFeature : targetOpts.featuresAsWritten) {
     llvm::StringRef userKeyString(llvm::StringRef(userFeature).drop_front(1));
     implicitFeaturesMap[userKeyString.str()] = (userFeature[0] == '+');
     // Check if the user provided a PTX version
     if (userKeyString.starts_with("ptx"))
       ptxVer = true;
   }

   // Set the default PTX version to `ptx61` if none was provided.
   // TODO: set the default PTX version based on the chip.
   if (!ptxVer)
     implicitFeaturesMap["ptx61"] = true;

   // Set the compute capability.
   implicitFeaturesMap[cpu.str()] = true;

   llvm::SmallVector<std::string> featuresVec;
   for (auto &implicitFeatureItem : implicitFeaturesMap) {
     featuresVec.push_back((llvm::Twine(implicitFeatureItem.second ? "+" : "-") +
                            implicitFeatureItem.first().str())
                               .str());
   }
   llvm::sort(featuresVec);
   return llvm::join(featuresVec, ",");
 }

 std::string CompilerInstance::getTargetFeatures() {
   const TargetOptions &targetOpts = getInvocation().getTargetOpts();
   const llvm::Triple triple(targetOpts.triple);

   // Clang does not append all target features to the clang -cc1 invocation.
   // Some target features are parsed implicitly by clang::TargetInfo child
   // class. Clang::TargetInfo classes are the basic clang classes and
   // they cannot be reused by Flang.
   // That's why we need to extract implicit target features and add
   // them to the target features specified by the user
   if (triple.isAMDGPU()) {
     return getExplicitAndImplicitAMDGPUTargetFeatures(getDiagnostics(),
                                                       targetOpts, triple);
   } else if (triple.isNVPTX()) {
     return getExplicitAndImplicitNVPTXTargetFeatures(getDiagnostics(),
                                                      targetOpts, triple);
   }
   return llvm::join(targetOpts.featuresAsWritten.begin(),
                     targetOpts.featuresAsWritten.end(), ",");
 }

 bool CompilerInstance::setUpTargetMachine() {
   const TargetOptions &targetOpts = getInvocation().getTargetOpts();
   const std::string &theTriple = targetOpts.triple;

   // Create `Target`
   std::string error;
   const llvm::Target *theTarget =
       llvm::TargetRegistry::lookupTarget(theTriple, error);
   if (!theTarget) {
     getDiagnostics().Report(clang::diag::err_fe_unable_to_create_target)
         << error;
     return false;
   }

   // Create `TargetMachine`
   const auto &CGOpts = getInvocation().getCodeGenOpts();
   std::optional<llvm::CodeGenOptLevel> OptLevelOrNone =
       llvm::CodeGenOpt::getLevel(CGOpts.OptimizationLevel);
   assert(OptLevelOrNone && "Invalid optimization level!");
   llvm::CodeGenOptLevel OptLevel = *OptLevelOrNone;
   std::string featuresStr = getTargetFeatures();
   targetMachine.reset(theTarget->createTargetMachine(
       theTriple, /*CPU=*/targetOpts.cpu,
       /*Features=*/featuresStr, llvm::TargetOptions(),
       /*Reloc::Model=*/CGOpts.getRelocationModel(),
       /*CodeModel::Model=*/std::nullopt, OptLevel));
   assert(targetMachine && "Failed to create TargetMachine");
   return true;
 }
	//===--- CompilerInstance.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
	//
	//===----------------------------------------------------------------------===//
	//
	// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
	//
	//===----------------------------------------------------------------------===//

	#include "flang/Frontend/CompilerInstance.h"
	#include "flang/Common/Fortran-features.h"
	#include "flang/Frontend/CompilerInvocation.h"
	#include "flang/Frontend/TextDiagnosticPrinter.h"
	#include "flang/Parser/parsing.h"
	#include "flang/Parser/provenance.h"
	#include "flang/Semantics/semantics.h"
	#include "clang/Basic/DiagnosticFrontend.h"
	#include "llvm/ADT/StringExtras.h"
	#include "llvm/MC/TargetRegistry.h"
	#include "llvm/Support/Errc.h"
	#include "llvm/Support/Error.h"
	#include "llvm/Support/FileSystem.h"
	#include "llvm/Support/Path.h"
	#include "llvm/Support/raw_ostream.h"
	#include "llvm/TargetParser/TargetParser.h"
	#include "llvm/TargetParser/Triple.h"

	using namespace Fortran::frontend;

	CompilerInstance::CompilerInstance()
	: invocation(new CompilerInvocation()),
	allSources(new Fortran::parser::AllSources()),
	allCookedSources(new Fortran::parser::AllCookedSources(*allSources)),
	parsing(new Fortran::parser::Parsing(*allCookedSources)) {
	// TODO: This is a good default during development, but ultimately we should
	// give the user the opportunity to specify this.
	allSources->set_encoding(Fortran::parser::Encoding::UTF_8);
	}

	CompilerInstance::~CompilerInstance() {
	assert(outputFiles.empty() && "Still output files in flight?");
	}

	void CompilerInstance::setInvocation(
	std::shared_ptr<CompilerInvocation> value) {
	invocation = std::move(value);
	}

	void CompilerInstance::setSemaOutputStream(raw_ostream &value) {
	ownedSemaOutputStream.release();
	semaOutputStream = &value;
	}

	void CompilerInstance::setSemaOutputStream(std::unique_ptr<raw_ostream> value) {
	ownedSemaOutputStream.swap(value);
	semaOutputStream = ownedSemaOutputStream.get();
	}

	// Helper method to generate the path of the output file. The following logic
	// applies:
	// 1. If the user specifies the output file via `-o`, then use that (i.e.
	// the outputFilename parameter).
	// 2. If the user does not specify the name of the output file, derive it from
	// the input file (i.e. inputFilename + extension)
	// 3. If the output file is not specified and the input file is `-`, then set
	// the output file to `-` as well.
	static std::string getOutputFilePath(llvm::StringRef outputFilename,
	llvm::StringRef inputFilename,
	llvm::StringRef extension) {

	// Output filename _is_ specified. Just use that.
	if (!outputFilename.empty())
	return std::string(outputFilename);

	// Output filename _is not_ specified. Derive it from the input file name.
	std::string outFile = "-";
	if (!extension.empty() && (inputFilename != "-")) {
	llvm::SmallString<128> path(inputFilename);
	llvm::sys::path::replace_extension(path, extension);
	outFile = std::string(path);
	}

	return outFile;
	}

	std::unique_ptr<llvm::raw_pwrite_stream>
	CompilerInstance::createDefaultOutputFile(bool binary, llvm::StringRef baseName,
	llvm::StringRef extension) {

	// Get the path of the output file
	std::string outputFilePath =
	getOutputFilePath(getFrontendOpts().outputFile, baseName, extension);

	// Create the output file
	llvm::Expected<std::unique_ptr<llvm::raw_pwrite_stream>> os =
	createOutputFileImpl(outputFilePath, binary);

	// If successful, add the file to the list of tracked output files and
	// return.
	if (os) {
	outputFiles.emplace_back(OutputFile(outputFilePath));
	return std::move(*os);
	}

	// If unsuccessful, issue an error and return Null
	unsigned diagID = getDiagnostics().getCustomDiagID(
	clang::DiagnosticsEngine::Error, "unable to open output file '%0': '%1'");
	getDiagnostics().Report(diagID)
	<< outputFilePath << llvm::errorToErrorCode(os.takeError()).message();
	return nullptr;
	}

	llvm::Expected<std::unique_ptr<llvm::raw_pwrite_stream>>
	CompilerInstance::createOutputFileImpl(llvm::StringRef outputFilePath,
	bool binary) {

	// Creates the file descriptor for the output file
	std::unique_ptr<llvm::raw_fd_ostream> os;

	std::error_code error;
	os.reset(new llvm::raw_fd_ostream(
	outputFilePath, error,
	(binary ? llvm::sys::fs::OF_None : llvm::sys::fs::OF_TextWithCRLF)));
	if (error) {
	return llvm::errorCodeToError(error);
	}

	// For seekable streams, just return the stream corresponding to the output
	// file.
	if (!binary \|\| os->supportsSeeking())
	return std::move(os);

	// For non-seekable streams, we need to wrap the output stream into something
	// that supports 'pwrite' and takes care of the ownership for us.
	return std::make_unique<llvm::buffer_unique_ostream>(std::move(os));
	}

	void CompilerInstance::clearOutputFiles(bool eraseFiles) {
	for (OutputFile &of : outputFiles)
	if (!of.filename.empty() && eraseFiles)
	llvm::sys::fs::remove(of.filename);

	outputFiles.clear();
	}

	bool CompilerInstance::executeAction(FrontendAction &act) {
	auto &invoc = this->getInvocation();

	llvm::Triple targetTriple{llvm::Triple(invoc.getTargetOpts().triple)};
	if (targetTriple.getArch() == llvm::Triple::ArchType::x86_64) {
	invoc.getDefaultKinds().set_quadPrecisionKind(10);
	}

	// Set some sane defaults for the frontend.
	invoc.setDefaultFortranOpts();
	// Update the fortran options based on user-based input.
	invoc.setFortranOpts();
	// Set the encoding to read all input files in based on user input.
	allSources->set_encoding(invoc.getFortranOpts().encoding);
	if (!setUpTargetMachine())
	return false;
	// Create the semantics context
	semaContext = invoc.getSemanticsCtx(*allCookedSources, getTargetMachine());
	// Set options controlling lowering to FIR.
	invoc.setLoweringOptions();

	// Run the frontend action `act` for every input file.
	for (const FrontendInputFile &fif : getFrontendOpts().inputs) {
	if (act.beginSourceFile(*this, fif)) {
	if (llvm::Error err = act.execute()) {
	consumeError(std::move(err));
	}
	act.endSourceFile();
	}
	}
	return !getDiagnostics().getClient()->getNumErrors();
	}

	void CompilerInstance::createDiagnostics(clang::DiagnosticConsumer *client,
	bool shouldOwnClient) {
	diagnostics =
	createDiagnostics(&getDiagnosticOpts(), client, shouldOwnClient);
	}

	clang::IntrusiveRefCntPtr<clang::DiagnosticsEngine>
	CompilerInstance::createDiagnostics(clang::DiagnosticOptions *opts,
	clang::DiagnosticConsumer *client,
	bool shouldOwnClient) {
	clang::IntrusiveRefCntPtr<clang::DiagnosticIDs> diagID(
	new clang::DiagnosticIDs());
	clang::IntrusiveRefCntPtr<clang::DiagnosticsEngine> diags(
	new clang::DiagnosticsEngine(diagID, opts));

	// Create the diagnostic client for reporting errors or for
	// implementing -verify.
	if (client) {
	diags->setClient(client, shouldOwnClient);
	} else {
	diags->setClient(new TextDiagnosticPrinter(llvm::errs(), opts));
	}
	return diags;
	}

	// Get feature string which represents combined explicit target features
	// for AMD GPU and the target features specified by the user
	static std::string
	getExplicitAndImplicitAMDGPUTargetFeatures(clang::DiagnosticsEngine &diags,
	const TargetOptions &targetOpts,
	const llvm::Triple triple) {
	llvm::StringRef cpu = targetOpts.cpu;
	llvm::StringMap<bool> implicitFeaturesMap;
	std::string errorMsg;
	// Get the set of implicit target features
	llvm::AMDGPU::fillAMDGPUFeatureMap(cpu, triple, implicitFeaturesMap);

	// Add target features specified by the user
	for (auto &userFeature : targetOpts.featuresAsWritten) {
	std::string userKeyString = userFeature.substr(1);
	implicitFeaturesMap[userKeyString] = (userFeature[0] == '+');
	}

	if (!llvm::AMDGPU::insertWaveSizeFeature(cpu, triple, implicitFeaturesMap,
	errorMsg)) {
	unsigned diagID = diags.getCustomDiagID(clang::DiagnosticsEngine::Error,
	"Unsupported feature ID: %0");
	diags.Report(diagID) << errorMsg.data();
	return std::string();
	}

	llvm::SmallVector<std::string> featuresVec;
	for (auto &implicitFeatureItem : implicitFeaturesMap) {
	featuresVec.push_back((llvm::Twine(implicitFeatureItem.second ? "+" : "-") +
	implicitFeatureItem.first().str())
	.str());
	}
	llvm::sort(featuresVec);
	return llvm::join(featuresVec, ",");
	}

	// Get feature string which represents combined explicit target features
	// for NVPTX and the target features specified by the user/
	// TODO: Have a more robust target conf like `clang/lib/Basic/Targets/NVPTX.cpp`
	static std::string
	getExplicitAndImplicitNVPTXTargetFeatures(clang::DiagnosticsEngine &diags,
	const TargetOptions &targetOpts,
	const llvm::Triple triple) {
	llvm::StringRef cpu = targetOpts.cpu;
	llvm::StringMap<bool> implicitFeaturesMap;
	std::string errorMsg;
	bool ptxVer = false;

	// Add target features specified by the user
	for (auto &userFeature : targetOpts.featuresAsWritten) {
	llvm::StringRef userKeyString(llvm::StringRef(userFeature).drop_front(1));
	implicitFeaturesMap[userKeyString.str()] = (userFeature[0] == '+');
	// Check if the user provided a PTX version
	if (userKeyString.starts_with("ptx"))
	ptxVer = true;
	}

	// Set the default PTX version to `ptx61` if none was provided.
	// TODO: set the default PTX version based on the chip.
	if (!ptxVer)
	implicitFeaturesMap["ptx61"] = true;

	// Set the compute capability.
	implicitFeaturesMap[cpu.str()] = true;

	llvm::SmallVector<std::string> featuresVec;
	for (auto &implicitFeatureItem : implicitFeaturesMap) {
	featuresVec.push_back((llvm::Twine(implicitFeatureItem.second ? "+" : "-") +
	implicitFeatureItem.first().str())
	.str());
	}
	llvm::sort(featuresVec);
	return llvm::join(featuresVec, ",");
	}

	std::string CompilerInstance::getTargetFeatures() {
	const TargetOptions &targetOpts = getInvocation().getTargetOpts();
	const llvm::Triple triple(targetOpts.triple);

	// Clang does not append all target features to the clang -cc1 invocation.
	// Some target features are parsed implicitly by clang::TargetInfo child
	// class. Clang::TargetInfo classes are the basic clang classes and
	// they cannot be reused by Flang.
	// That's why we need to extract implicit target features and add
	// them to the target features specified by the user
	if (triple.isAMDGPU()) {
	return getExplicitAndImplicitAMDGPUTargetFeatures(getDiagnostics(),
	targetOpts, triple);
	} else if (triple.isNVPTX()) {
	return getExplicitAndImplicitNVPTXTargetFeatures(getDiagnostics(),
	targetOpts, triple);
	}
	return llvm::join(targetOpts.featuresAsWritten.begin(),
	targetOpts.featuresAsWritten.end(), ",");
	}

	bool CompilerInstance::setUpTargetMachine() {
	const TargetOptions &targetOpts = getInvocation().getTargetOpts();
	const std::string &theTriple = targetOpts.triple;

	// Create `Target`
	std::string error;
	const llvm::Target *theTarget =
	llvm::TargetRegistry::lookupTarget(theTriple, error);
	if (!theTarget) {
	getDiagnostics().Report(clang::diag::err_fe_unable_to_create_target)
	<< error;
	return false;
	}

	// Create `TargetMachine`
	const auto &CGOpts = getInvocation().getCodeGenOpts();
	std::optional<llvm::CodeGenOptLevel> OptLevelOrNone =
	llvm::CodeGenOpt::getLevel(CGOpts.OptimizationLevel);
	assert(OptLevelOrNone && "Invalid optimization level!");
	llvm::CodeGenOptLevel OptLevel = *OptLevelOrNone;
	std::string featuresStr = getTargetFeatures();
	targetMachine.reset(theTarget->createTargetMachine(
	theTriple, /CPU=/targetOpts.cpu,
	/Features=/featuresStr, llvm::TargetOptions(),
	/Reloc::Model=/CGOpts.getRelocationModel(),
	/CodeModel::Model=/std::nullopt, OptLevel));
	assert(targetMachine && "Failed to create TargetMachine");
	return true;
	}