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[LTO] Driver support for -lto_library flag #38264

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Merged
merged 4 commits into from
Jul 15, 2021
Merged

[LTO] Driver support for -lto_library flag #38264

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35735e7
[LTO] Driver support for -lto_library flag
jslegendre Jul 5, 2021
ebd5992
Use Swift-style args for Driver
jslegendre Jul 6, 2021
7fa9fcf
Update flag options
jslegendre Jul 6, 2021
1a38168
Fix relative libLTO path
jslegendre Jul 12, 2021
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2 changes: 2 additions & 0 deletions include/swift/Driver/Driver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,8 @@ class OutputInfo {

LTOKind LTOVariant = LTOKind::None;

std::string LibLTOPath;

/// Describes if and how the output of compile actions should be
/// linked together.
LinkKind LinkAction = LinkKind::None;
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4 changes: 4 additions & 0 deletions include/swift/Option/Options.td
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Expand Up @@ -549,6 +549,10 @@ def disable_bridging_pch : Flag<["-"], "disable-bridging-pch">,
def lto : Joined<["-"], "lto=">,
Flags<[FrontendOption, NoInteractiveOption]>,
HelpText<"Specify the LTO type to either 'llvm-thin' or 'llvm-full'">;

def lto_library : Separate<["-"], "lto-library">,
Flags<[FrontendOption, ArgumentIsPath, NoInteractiveOption]>,
HelpText<"Perform LTO with <lto-library>">, MetaVarName<"<lto-library>">;

def access_notes_path : Separate<["-"], "access-notes-path">,
Flags<[FrontendOption, ArgumentIsPath]>,
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25 changes: 22 additions & 3 deletions lib/Driver/DarwinToolChains.cpp
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Expand Up @@ -321,10 +321,29 @@ toolchains::Darwin::addArgsToLinkARCLite(ArgStringList &Arguments,

void toolchains::Darwin::addLTOLibArgs(ArgStringList &Arguments,
const JobContext &context) const {
llvm::SmallString<128> LTOLibPath;
if (findXcodeClangLibPath("libLTO.dylib", LTOLibPath)) {
if (!context.OI.LibLTOPath.empty()) {
// Check for user-specified LTO library.
Arguments.push_back("-lto_library");
Arguments.push_back(context.Args.MakeArgString(LTOLibPath));
Arguments.push_back(context.Args.MakeArgString(context.OI.LibLTOPath));
} else {
// Check for relative libLTO.dylib. This would be the expected behavior in an
// Xcode toolchain.
StringRef P = llvm::sys::path::parent_path(getDriver().getSwiftProgramPath());
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@owenv owenv Jul 10, 2021

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I think P is going to be <toolchain root>/usr/bin/ here, so we'll end up checking for libLTO in <toolchain root>/usr/bin/lib instead of <toolchain root>/usr/lib. I can't think of a good way to write a lit test for this unfortunately.

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@jslegendre jslegendre Jul 12, 2021

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Thanks for pointing this out. Fixed in latest commit.

llvm::SmallString<128> LibLTOPath(P);
llvm::sys::path::remove_filename(LibLTOPath); // Remove '/bin'
llvm::sys::path::append(LibLTOPath, "lib");
llvm::sys::path::append(LibLTOPath, "libLTO.dylib");
if (llvm::sys::fs::exists(LibLTOPath)) {
Arguments.push_back("-lto_library");
Arguments.push_back(context.Args.MakeArgString(LibLTOPath));
} else {
// Use libLTO.dylib from the default toolchain if a relative one does not exist.
llvm::SmallString<128> LibLTOPath;
if (findXcodeClangLibPath("libLTO.dylib", LibLTOPath)) {
Arguments.push_back("-lto_library");
Arguments.push_back(context.Args.MakeArgString(LibLTOPath));
}
}
}
}

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6 changes: 6 additions & 0 deletions lib/Driver/Driver.cpp
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Expand Up @@ -1448,6 +1448,12 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
A->getAsString(Args), A->getValue());
}

if (const Arg *A = Args.getLastArg(options::OPT_lto_library)) {
OI.LibLTOPath = A->getValue();
} else {
OI.LibLTOPath = "";
}

auto CompilerOutputType = OI.LTOVariant != OutputInfo::LTOKind::None
? file_types::TY_LLVM_BC
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15 changes: 15 additions & 0 deletions test/Driver/link-time-opt-darwin-ld-lib.swift
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Expand Up @@ -24,3 +24,18 @@
// CHECK-SIMPLE-FULL-macosx: ld
// CHECK-SIMPLE-FULL-macosx-DAG: -lto_library {{.+}}/lib/libLTO.dylib
// CHECK-SIMPLE-FULL-macosx-DAG: [[OBJECTFILE]]


// Check that driver does not see libLTO.dylib as an input

// RUN: %swiftc_driver -driver-print-jobs %S/../Inputs/empty.swift -lto=llvm-full -lto-library /foo/libLTO.dylib -target x86_64-apple-macosx10.9 | %FileCheck %s --check-prefix=CHECK-SIMPLE-LTO-LIB --check-prefix=CHECK-SIMPLE-LTO-LIB-macosx

// CHECK-SIMPLE-LTO-LIB: swift
// CHECK-SIMPLE-LTO-LIB-DAG: -emit-bc
// CHECK-SIMPLE-LTO-LIB-DAG: -lto=llvm-full
// CHECK-SIMPLE-LTO-LIB-NOT: -lto-library /foo/libLTO.dylib
// CHECK-SIMPLE-LTO-LIB-DAG: -o [[OBJECTFILE:.*\.bc]]

// CHECK-SIMPLE-LTO-LIB-macosx: ld
// CHECK-SIMPLE-LTO-LIB-macosx-DAG: -lto_library /foo/libLTO.dylib
// CHECK-SIMPLE-LTO-LIB-macosx-DAG: [[OBJECTFILE]]