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[LTO] Support LLVM LTO for driver
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This commit adds LTO support for handling linker options and LLVM BC
emission. Even for ELF, swift-autolink-extract is unnecessary because
linker options are embeded in LLVM BC content when LTO.
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@kateinoigakukun
kateinoigakukun committed Jul 31, 2020
1 parent 063d420 commit d6cddaa
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Showing 14 changed files with 299 additions and 21 deletions.
8 changes: 6 additions & 2 deletions include/swift/Driver/Action.h
View file
Expand Up @@ -328,16 +328,20 @@ class GeneratePCHJobAction : public JobAction {
class DynamicLinkJobAction : public JobAction {
virtual void anchor();
LinkKind Kind;
bool ShouldPerformLTO;

public:
DynamicLinkJobAction(ArrayRef<const Action *> Inputs, LinkKind K)
DynamicLinkJobAction(ArrayRef<const Action *> Inputs, LinkKind K,
bool ShouldPerformLTO)
: JobAction(Action::Kind::DynamicLinkJob, Inputs, file_types::TY_Image),
Kind(K) {
Kind(K), ShouldPerformLTO(ShouldPerformLTO) {
assert(Kind != LinkKind::None && Kind != LinkKind::StaticLibrary);
}

LinkKind getKind() const { return Kind; }

bool shouldPerformLTO() const { return ShouldPerformLTO; }

static bool classof(const Action *A) {
return A->getKind() == Action::Kind::DynamicLinkJob;
}
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8 changes: 8 additions & 0 deletions include/swift/Driver/Driver.h
View file
Expand Up @@ -101,6 +101,14 @@ class OutputInfo {
/// The output type which should be used for compile actions.
file_types::ID CompilerOutputType = file_types::ID::TY_INVALID;

enum class LTOKind {
None,
LLVMThin,
LLVMFull,
};

LTOKind LTOVariant = LTOKind::None;

/// Describes if and how the output of compile actions should be
/// linked together.
LinkKind LinkAction = LinkKind::None;
Expand Down
42 changes: 35 additions & 7 deletions lib/Driver/DarwinToolChains.cpp
View file
Expand Up @@ -202,6 +202,19 @@ static bool findXcodeClangPath(llvm::SmallVectorImpl<char> &path) {
return !path.empty();
}

static bool findXcodeClangLibPath(const Twine &libName,
llvm::SmallVectorImpl<char> &path) {
assert(path.empty());

if (!findXcodeClangPath(path)) {
return false;
}
llvm::sys::path::remove_filename(path); // 'clang'
llvm::sys::path::remove_filename(path); // 'bin'
llvm::sys::path::append(path, "lib", libName);
return true;
}

static void addVersionString(const ArgList &inputArgs, ArgStringList &arguments,
unsigned major, unsigned minor, unsigned micro) {
llvm::SmallString<8> buf;
Expand Down Expand Up @@ -239,12 +252,15 @@ toolchains::Darwin::addLinkerInputArgs(InvocationInfo &II,
Arguments.push_back("-filelist");
Arguments.push_back(context.getTemporaryFilePath("inputs", "LinkFileList"));
II.FilelistInfos.push_back(
{Arguments.back(), file_types::TY_Object,
{Arguments.back(), context.OI.CompilerOutputType,
FilelistInfo::WhichFiles::InputJobsAndSourceInputActions});
} else {
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);
}


Expand Down Expand Up @@ -274,11 +290,7 @@ static void findARCLiteLibPath(const toolchains::Darwin &TC,
// If we don't have a 'lib/arc/' directory, find the "arclite" library
// relative to the Clang in the active Xcode.
ARCLiteLib.clear();
if (findXcodeClangPath(ARCLiteLib)) {
llvm::sys::path::remove_filename(ARCLiteLib); // 'clang'
llvm::sys::path::remove_filename(ARCLiteLib); // 'bin'
llvm::sys::path::append(ARCLiteLib, "lib", "arc");
}
findXcodeClangLibPath("arc", ARCLiteLib);
}
}

Expand Down Expand Up @@ -307,6 +319,15 @@ toolchains::Darwin::addArgsToLinkARCLite(ArgStringList &Arguments,
}
}

void toolchains::Darwin::addLTOLibArgs(ArgStringList &Arguments,
const JobContext &context) const {
llvm::SmallString<128> LTOLibPath;
if (findXcodeClangLibPath("libLTO.dylib", LTOLibPath)) {
Arguments.push_back("-lto_library");
Arguments.push_back(context.Args.MakeArgString(LTOLibPath));
}
}

void
toolchains::Darwin::addSanitizerArgs(ArgStringList &Arguments,
const DynamicLinkJobAction &job,
Expand Down Expand Up @@ -761,6 +782,10 @@ toolchains::Darwin::constructInvocation(const DynamicLinkJobAction &job,

addArgsToLinkARCLite(Arguments, context);

if (job.shouldPerformLTO()) {
addLTOLibArgs(Arguments, context);
}

for (const Arg *arg :
context.Args.filtered(options::OPT_F, options::OPT_Fsystem)) {
Arguments.push_back("-F");
Expand Down Expand Up @@ -828,14 +853,17 @@ toolchains::Darwin::constructInvocation(const StaticLinkJobAction &job,
if (context.shouldUseInputFileList()) {
Arguments.push_back("-filelist");
Arguments.push_back(context.getTemporaryFilePath("inputs", "LinkFileList"));
II.FilelistInfos.push_back({Arguments.back(), file_types::TY_Object,
II.FilelistInfos.push_back({Arguments.back(), context.OI.CompilerOutputType,
FilelistInfo::WhichFiles::InputJobs});
} else {
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
}

addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);

Arguments.push_back("-o");

Expand Down
39 changes: 29 additions & 10 deletions lib/Driver/Driver.cpp
View file
Expand Up @@ -1433,12 +1433,29 @@ static bool isSDKTooOld(StringRef sdkPath, const llvm::Triple &target) {
void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
const bool BatchMode, const InputFileList &Inputs,
OutputInfo &OI) const {

if (const Arg *A = Args.getLastArg(options::OPT_lto)) {
auto LTOVariant =
llvm::StringSwitch<Optional<OutputInfo::LTOKind>>(A->getValue())
.Case("llvm-thin", OutputInfo::LTOKind::LLVMThin)
.Case("llvm-full", OutputInfo::LTOKind::LLVMFull)
.Default(llvm::None);
if (LTOVariant)
OI.LTOVariant = LTOVariant.getValue();
else
Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
A->getAsString(Args), A->getValue());
}

auto CompilerOutputType = OI.LTOVariant != OutputInfo::LTOKind::None
? file_types::TY_LLVM_BC
: file_types::TY_Object;
// By default, the driver does not link its output; this will be updated
// appropriately below if linking is required.

OI.CompilerOutputType = driverKind == DriverKind::Interactive
? file_types::TY_Nothing
: file_types::TY_Object;
: CompilerOutputType;

if (const Arg *A = Args.getLastArg(options::OPT_num_threads)) {
if (BatchMode) {
Expand Down Expand Up @@ -1468,14 +1485,14 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
diag::error_static_emit_executable_disallowed);

OI.LinkAction = LinkKind::Executable;
OI.CompilerOutputType = file_types::TY_Object;
OI.CompilerOutputType = CompilerOutputType;
break;

case options::OPT_emit_library:
OI.LinkAction = Args.hasArg(options::OPT_static) ?
LinkKind::StaticLibrary :
LinkKind::DynamicLibrary;
OI.CompilerOutputType = file_types::TY_Object;
OI.CompilerOutputType = CompilerOutputType;
break;

case options::OPT_static:
Expand Down Expand Up @@ -2119,15 +2136,16 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
MergeModuleAction = C.createAction<MergeModuleJobAction>(AllModuleInputs);
}

bool shouldPerformLTO = OI.LTOVariant != OutputInfo::LTOKind::None;
if (OI.shouldLink() && !AllLinkerInputs.empty()) {
JobAction *LinkAction = nullptr;

if (OI.LinkAction == LinkKind::StaticLibrary) {
LinkAction = C.createAction<StaticLinkJobAction>(AllLinkerInputs,
OI.LinkAction);
LinkAction =
C.createAction<StaticLinkJobAction>(AllLinkerInputs, OI.LinkAction);
} else {
LinkAction = C.createAction<DynamicLinkJobAction>(AllLinkerInputs,
OI.LinkAction);
LinkAction = C.createAction<DynamicLinkJobAction>(
AllLinkerInputs, OI.LinkAction, shouldPerformLTO);
}

// On ELF platforms there's no built in autolinking mechanism, so we
Expand All @@ -2149,9 +2167,10 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
AutolinkExtractInputs.push_back(A);
}
const bool AutolinkExtractRequired =
(Triple.getObjectFormat() == llvm::Triple::ELF && !Triple.isPS4()) ||
Triple.getObjectFormat() == llvm::Triple::Wasm ||
Triple.isOSCygMing();
((Triple.getObjectFormat() == llvm::Triple::ELF && !Triple.isPS4()) ||
Triple.getObjectFormat() == llvm::Triple::Wasm ||
Triple.isOSCygMing()) &&
!shouldPerformLTO;
if (!AutolinkExtractInputs.empty() && AutolinkExtractRequired) {
auto *AutolinkExtractAction =
C.createAction<AutolinkExtractJobAction>(AutolinkExtractInputs);
Expand Down
15 changes: 15 additions & 0 deletions lib/Driver/ToolChains.cpp
View file
Expand Up @@ -128,6 +128,19 @@ static bool addOutputsOfType(ArgStringList &Arguments,
return Added;
}

static void addLTOArgs(const OutputInfo &OI, ArgStringList &arguments) {
switch (OI.LTOVariant) {
case OutputInfo::LTOKind::None:
break;
case OutputInfo::LTOKind::LLVMThin:
arguments.push_back("-lto=llvm-thin");
break;
case OutputInfo::LTOKind::LLVMFull:
arguments.push_back("-lto=llvm-full");
break;
}
}

void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
const CommandOutput &output,
const ArgList &inputArgs,
Expand Down Expand Up @@ -284,6 +297,8 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
arguments.push_back(inputArgs.MakeArgString(workingDirectory));
}

addLTOArgs(OI, arguments);

// -g implies -enable-anonymous-context-mangled-names, because the extra
// metadata aids debugging.
if (inputArgs.hasArg(options::OPT_g)) {
Expand Down
3 changes: 3 additions & 0 deletions lib/Driver/ToolChains.h
View file
Expand Up @@ -48,6 +48,9 @@ class LLVM_LIBRARY_VISIBILITY Darwin : public ToolChain {
void addDeploymentTargetArgs(llvm::opt::ArgStringList &Arguments,
const JobContext &context) const;

void addLTOLibArgs(llvm::opt::ArgStringList &Arguments,
const JobContext &context) const;

void addCommonFrontendArgs(
const OutputInfo &OI, const CommandOutput &output,
const llvm::opt::ArgList &inputArgs,
Expand Down
34 changes: 32 additions & 2 deletions lib/Driver/UnixToolChains.cpp
View file
Expand Up @@ -72,7 +72,10 @@ ToolChain::InvocationInfo toolchains::GenericUnix::constructInvocation(

addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);

Arguments.push_back("-o");
Arguments.push_back(
Expand Down Expand Up @@ -165,9 +168,18 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,

// Select the linker to use.
std::string Linker;
if (context.OI.LTOVariant != OutputInfo::LTOKind::None) {
// Force to use lld for LTO on Unix-like platform (not including Darwin)
// because we don't support gold LTO or something else except for lld LTO
// at this time.
Linker = "lld";
}

if (const Arg *A = context.Args.getLastArg(options::OPT_use_ld)) {
Linker = A->getValue();
} else {
}

if (Linker.empty()) {
Linker = getDefaultLinker();
}
if (!Linker.empty()) {
Expand Down Expand Up @@ -218,6 +230,17 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,
Arguments.push_back("-pie");
}

switch (context.OI.LTOVariant) {
case OutputInfo::LTOKind::LLVMThin:
Arguments.push_back("-flto=thin");
break;
case OutputInfo::LTOKind::LLVMFull:
Arguments.push_back("-flto=full");
break;
case OutputInfo::LTOKind::None:
break;
}

bool staticExecutable = false;
bool staticStdlib = false;

Expand Down Expand Up @@ -253,7 +276,10 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,

addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);

for (const Arg *arg :
context.Args.filtered(options::OPT_F, options::OPT_Fsystem)) {
Expand Down Expand Up @@ -368,15 +394,19 @@ toolchains::GenericUnix::constructInvocation(const StaticLinkJobAction &job,
ArgStringList Arguments;

// Configure the toolchain.
const char *AR = "ar";
const char *AR =
context.OI.LTOVariant != OutputInfo::LTOKind::None ? "llvm-ar" : "ar";
Arguments.push_back("crs");

Arguments.push_back(
context.Args.MakeArgString(context.Output.getPrimaryOutputFilename()));

addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);

InvocationInfo II{AR, Arguments};

Expand Down
21 changes: 21 additions & 0 deletions lib/Driver/WindowsToolChains.cpp
View file
Expand Up @@ -76,6 +76,24 @@ toolchains::Windows::constructInvocation(const DynamicLinkJobAction &job,
if (const Arg *A = context.Args.getLastArg(options::OPT_use_ld)) {
Linker = A->getValue();
}

switch (context.OI.LTOVariant) {
case OutputInfo::LTOKind::LLVMThin:
Arguments.push_back("-flto=thin");
break;
case OutputInfo::LTOKind::LLVMFull:
Arguments.push_back("-flto=full");
break;
case OutputInfo::LTOKind::None:
break;
}

if (Linker.empty() && context.OI.LTOVariant != OutputInfo::LTOKind::None) {
// Force to use lld for LTO on Windows because we don't support link LTO or
// something else except for lld LTO at this time.
Linker = "lld";
}

if (!Linker.empty())
Arguments.push_back(context.Args.MakeArgString("-fuse-ld=" + Linker));

Expand Down Expand Up @@ -143,7 +161,10 @@ toolchains::Windows::constructInvocation(const DynamicLinkJobAction &job,

addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_Object);
addPrimaryInputsOfType(Arguments, context.Inputs, context.Args,
file_types::TY_LLVM_BC);
addInputsOfType(Arguments, context.InputActions, file_types::TY_Object);
addInputsOfType(Arguments, context.InputActions, file_types::TY_LLVM_BC);

for (const Arg *arg :
context.Args.filtered(options::OPT_F, options::OPT_Fsystem)) {
Expand Down

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