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[LTO] Support LLVM level link time optimization on Darwin, Linux and Windows #31146

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Merged
merged 1 commit into from
Jun 5, 2020
Merged

[LTO] Support LLVM level link time optimization on Darwin, Linux and Windows #31146

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9 changes: 9 additions & 0 deletions include/swift/AST/IRGenOptions.h
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,12 @@ enum class IRGenDebugInfoFormat : unsigned {
CodeView
};

enum class IRGenLLVMLTOKind : unsigned {
None,
Thin,
Full
};

enum class IRGenEmbedMode : unsigned {
None,
EmbedMarker,
Expand Down Expand Up @@ -221,6 +227,8 @@ class IRGenOptions {
/// Whether we should embed the bitcode file.
IRGenEmbedMode EmbedMode : 2;

IRGenLLVMLTOKind LLVMLTOKind: 2;

/// Add names to LLVM values.
unsigned HasValueNamesSetting : 1;
unsigned ValueNames : 1;
Expand Down Expand Up @@ -323,6 +331,7 @@ class IRGenOptions {
DisableFPElimLeaf(false),
DisableFPElim(true), Playground(false), EmitStackPromotionChecks(false),
FunctionSections(false), PrintInlineTree(false), EmbedMode(IRGenEmbedMode::None),
LLVMLTOKind(IRGenLLVMLTOKind::None),
HasValueNamesSetting(false), ValueNames(false),
EnableReflectionMetadata(true), EnableReflectionNames(true),
EnableAnonymousContextMangledNames(false), ForcePublicLinkage(false),
Expand Down
7 changes: 5 additions & 2 deletions include/swift/Driver/Action.h
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Expand Up @@ -329,16 +329,19 @@ class GeneratePCHJobAction : public JobAction {
class DynamicLinkJobAction : public JobAction {
virtual void anchor();
LinkKind Kind;
bool LTO;

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

LinkKind getKind() const { return Kind; }

bool PerformLTO() const { return LTO; }

static bool classof(const Action *A) {
return A->getKind() == Action::Kind::DynamicLinkJob;
}
Expand Down
8 changes: 8 additions & 0 deletions include/swift/Driver/Driver.h
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Expand Up @@ -102,6 +102,14 @@ 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
4 changes: 4 additions & 0 deletions include/swift/Option/Options.td
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Expand Up @@ -499,6 +499,10 @@ def disable_bridging_pch : Flag<["-"], "disable-bridging-pch">,
Flags<[HelpHidden]>,
HelpText<"Disable automatic generation of bridging PCH files">;

def lto : Joined<["-"], "lto=">,
Flags<[FrontendOption, NoInteractiveOption]>,
HelpText<"Specify the LTO type to either 'llvm' or 'llvm-full'">;

// Experimental feature options

// Note: this flag will be removed when JVP/differential generation in the
Expand Down
28 changes: 26 additions & 2 deletions lib/Driver/DarwinToolChains.cpp
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Expand Up @@ -238,12 +238,15 @@ 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 @@ -306,6 +309,20 @@ toolchains::Darwin::addArgsToLinkARCLite(ArgStringList &Arguments,
}
}

void
toolchains::Darwin::addLTOLibArgs(ArgStringList &Arguments,
const JobContext &context) const {
llvm::SmallString<128> LTOLibPath;
if (findXcodeClangPath(LTOLibPath)) {
llvm::sys::path::remove_filename(LTOLibPath); // 'clang'
llvm::sys::path::remove_filename(LTOLibPath); // 'bin'
llvm::sys::path::append(LTOLibPath, "lib", "libLTO.dylib");

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 @@ -723,6 +740,10 @@ toolchains::Darwin::constructInvocation(const DynamicLinkJobAction &job,

addArgsToLinkARCLite(Arguments, context);

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

for (const Arg *arg :
context.Args.filtered(options::OPT_F, options::OPT_Fsystem)) {
Arguments.push_back("-F");
Expand Down Expand Up @@ -790,14 +811,17 @@ 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
31 changes: 24 additions & 7 deletions lib/Driver/Driver.cpp
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Expand Up @@ -1427,12 +1427,15 @@ 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 {
auto LinkerInputType = Args.hasArg(options::OPT_lto)
? 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;
: LinkerInputType;

if (const Arg *A = Args.getLastArg(options::OPT_num_threads)) {
if (BatchMode) {
Expand Down Expand Up @@ -1462,14 +1465,14 @@ 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 = LinkerInputType;
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 = LinkerInputType;
break;

case options::OPT_static:
Expand Down Expand Up @@ -1779,6 +1782,18 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,

}

if (const Arg *A = Args.getLastArg(options::OPT_lto)) {
auto LTOVariant = llvm::StringSwitch<Optional<OutputInfo::LTOKind>>(A->getValue())
.Case("llvm", 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());
}

if (TC.getTriple().isOSWindows()) {
if (const Arg *A = Args.getLastArg(options::OPT_libc)) {
OI.RuntimeVariant =
Expand Down Expand Up @@ -2113,15 +2128,17 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
MergeModuleAction = C.createAction<MergeModuleJobAction>(AllModuleInputs);
}

auto PerformLTO = Args.hasArg(options::OPT_lto);
if (OI.shouldLink() && !AllLinkerInputs.empty()) {
JobAction *LinkAction = nullptr;

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

// On ELF platforms there's no built in autolinking mechanism, so we
Expand All @@ -2130,7 +2147,7 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
const auto &Triple = TC.getTriple();
SmallVector<const Action *, 2> AutolinkExtractInputs;
for (const Action *A : AllLinkerInputs)
if (A->getType() == file_types::TY_Object) {
if (A->getType() == OI.CompilerOutputType) {
// Shared objects on ELF platforms don't have a swift1_autolink_entries
// section in them because the section in the .o files is marked as
// SHF_EXCLUDE.
Expand All @@ -2146,7 +2163,7 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
(Triple.getObjectFormat() == llvm::Triple::ELF && !Triple.isPS4()) ||
Triple.getObjectFormat() == llvm::Triple::Wasm ||
Triple.isOSCygMing();
if (!AutolinkExtractInputs.empty() && AutolinkExtractRequired) {
if (!AutolinkExtractInputs.empty() && AutolinkExtractRequired && !PerformLTO) {
auto *AutolinkExtractAction =
C.createAction<AutolinkExtractJobAction>(AutolinkExtractInputs);
// Takes the same inputs as the linker...
Expand Down
5 changes: 5 additions & 0 deletions lib/Driver/ToolChains.cpp
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Expand Up @@ -519,6 +519,11 @@ ToolChain::constructInvocation(const CompileJobAction &job,
Arguments.push_back("-track-system-dependencies");
}

if (auto arg = context.Args.getLastArg(options::OPT_lto)) {
Arguments.push_back(context.Args.MakeArgString(
Twine("-lto=") + arg->getValue()));
}

context.Args.AddLastArg(
Arguments,
options::
Expand Down
3 changes: 3 additions & 0 deletions lib/Driver/ToolChains.h
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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
26 changes: 25 additions & 1 deletion lib/Driver/UnixToolChains.cpp
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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 @@ -167,6 +170,9 @@ toolchains::GenericUnix::constructInvocation(const DynamicLinkJobAction &job,
std::string Linker;
if (const Arg *A = context.Args.getLastArg(options::OPT_use_ld)) {
Linker = A->getValue();
} else if (context.OI.LTOVariant != OutputInfo::LTOKind::None) {
// Force to use lld for LTO
Linker = "lld";
} else {
Linker = getDefaultLinker();
}
Expand Down Expand Up @@ -218,6 +224,16 @@ 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 +269,11 @@ 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 +388,19 @@ toolchains::GenericUnix::constructInvocation(const StaticLinkJobAction &job,
ArgStringList Arguments;

// Configure the toolchain.
const char *AR = "ar";
const char *AR = "llvm-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
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