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Pass '-fpie' to the clang linker driver on Linux, instead of 'pie' #1900

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Pass '-fpie' to the clang linker driver on Linux, instead of 'pie' #1900

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4 changes: 2 additions & 2 deletions Sources/SwiftDriver/Jobs/GenericUnixToolchain+LinkerSupport.swift
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Expand Up @@ -101,9 +101,9 @@ extension GenericUnixToolchain {
commandLine.appendPath(toolsDir)
}

// Executables on Linux get -pie
// Executables on Linux get -fpie
if targetTriple.os == .linux && linkerOutputType == .executable {
commandLine.appendFlag("-pie")
commandLine.appendFlag("-fpie")
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I'm confused by this change. The spelling is -pie for the linker driver invocation, but -fpie for the compiler invocation (unless you are on certain platforms, where the spelling is -fPIE) under certain circumstances.

-pie is the equivalent of -shared but for executables.
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Thanks for clearing that up, I had confused the two. @cachemeifyoucan pointed out that the warning we get appears to be due to the Clang driver emitting it for platforms where the toolchain default for executables is PIE.
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I am actually unsure where the warning coming from before seeing the build log. I suggest it is better if you just pass -Xlinker -pie if you worried about unused argument warning.
}

// On some platforms we want to enable --build-id
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10 changes: 10 additions & 0 deletions Tests/SwiftDriverTests/SwiftDriverTests.swift
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Expand Up @@ -2069,6 +2069,16 @@ final class SwiftDriverTests: XCTestCase {
XCTAssertTrue(cmd.contains(subsequence: [.flag("-Xlinker"), .flag("-rpath=$ORIGIN"), .flag("foo")]))
}

do {
// Ensure executables get '-fpie'
var driver = try Driver(args: commonArgs + ["-emit-executable", "-L", "/tmp", "-target", "x86_64-unknown-linux"], env: env)
let plannedJobs = try driver.planBuild()
XCTAssertEqual(plannedJobs.count, 4)
let linkJob = plannedJobs[3]
let cmd = linkJob.commandLine
XCTAssertTrue(cmd.contains(subsequence: [.flag("-fpie")]))
}

do {
// Xlinker flags
// Ensure that Xlinker flags are passed as such to the clang linker invocation.
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