make lto a build param

rauhul · rauhul · commit 27132b4e953d · 2023-05-24T15:25:54.000-07:00
diff --git a/Sources/Build/BuildDescription/ClangTargetBuildDescription.swift b/Sources/Build/BuildDescription/ClangTargetBuildDescription.swift
@@ -293,6 +293,17 @@ public final class ClangTargetBuildDescription {
             // User arguments (from -Xcxx) should follow generated arguments to allow user overrides
             args += self.buildParameters.flags.cxxCompilerFlags
         }
+
+        // Enable the correct lto mode if requested.
+        switch self.buildParameters.linkTimeOptimizationMode {
+        case nil:
+            break
+        case .full:
+            args += ["-flto=full"]
+        case .thin:
+            args += ["-flto=thin"]
+        }
+
         return args
     }
 
diff --git a/Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift b/Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift
@@ -74,54 +74,24 @@ public final class SwiftTargetBuildDescription {
         self.target.sources.paths + self.derivedSources.paths + self.pluginDerivedSources.paths
     }
 
-    /// The list of all source files in the target, including the derived ones.
-    private var relativeSources: [RelativePath] {
-        self.target.sources.relativePaths + self.derivedSources.relativePaths + self
-            .pluginDerivedSources.relativePaths
-    }
-
     /// The list of all resource files in the target, including the derived ones.
     public var resources: [Resource] {
         self.target.underlyingTarget.resources + self.pluginDerivedResources
     }
 
-    private var producesBitcodeObjects: Bool {
-        get throws {
-            try self.compileArguments().contains {
-                    // Using -lto=x will result in bitcode generation.
-                    $0.hasPrefix("-lto=")
-                    // Using -embed-bitcode will result in bitcode generation.
-                    || $0 == "-embed-bitcode"
-                }
-        }
-    }
-
     /// The objects in this target, containing either machine code or bitcode
-    /// depending on the compiler flags used.
+    /// depending on the build parameters used.
     public var objects: [AbsolutePath] {
         get throws {
-            // Prefer bitcode objects over machine code objects if they are
-            // produced.
-            try self.producesBitcodeObjects
-                ? self.bitcodeObjects
-                : self.machineCodeObjects
-        }
-    }
-
-    /// The machine code objects in this target.
-    private var machineCodeObjects: [AbsolutePath] {
-        get throws {
-            try self.relativeSources.map {
-                try AbsolutePath(validating: "\($0.pathString).o", relativeTo: tempsPath)
-            }
-        }
-    }
-
-    /// The bitcode objects in this target.
-    private var bitcodeObjects: [AbsolutePath] {
-        get throws {
-            try self.relativeSources.map {
-                try AbsolutePath(validating: "\($0.pathString).bc", relativeTo: tempsPath)
+            let relativeSources = self.target.sources.relativePaths
+                + self.derivedSources.relativePaths
+                + self.pluginDerivedSources.relativePaths
+            let ltoEnabled = self.buildParameters.linkTimeOptimizationMode != nil
+            let objectFileExtension = ltoEnabled ? "bc" : "o"
+            return try relativeSources.map {
+                try AbsolutePath(
+                    validating: "\($0.pathString).\(objectFileExtension)",
+                    relativeTo: self.tempsPath)
             }
         }
     }
@@ -548,6 +518,16 @@ public final class SwiftTargetBuildDescription {
         // // User arguments (from -Xcxx) should follow generated arguments to allow user overrides
         // args += self.buildParameters.flags.cxxCompilerFlags.asSwiftcCXXCompilerFlags()
 
+        // Enable the correct lto mode if requested.
+        switch self.buildParameters.linkTimeOptimizationMode {
+        case nil:
+            break
+        case .full:
+            args += ["-lto=llvm-full"]
+        case .thin:
+            args += ["-lto=llvm-thin"]
+        }
+
         // suppress warnings if the package is remote
         if self.package.isRemote {
             args += ["-suppress-warnings"]
@@ -716,6 +696,16 @@ public final class SwiftTargetBuildDescription {
         // // User arguments (from -Xcxx) should follow generated arguments to allow user overrides
         // result += self.buildParameters.flags.cxxCompilerFlags.asSwiftcCXXCompilerFlags()
 
+        // Enable the correct lto mode if requested.
+        switch self.buildParameters.linkTimeOptimizationMode {
+        case nil:
+            break
+        case .full:
+            result += ["-lto=llvm-full"]
+        case .thin:
+            result += ["-lto=llvm-thin"]
+        }
+
         result += try self.macroArguments()
         return result
     }
@@ -766,13 +756,13 @@ public final class SwiftTargetBuildDescription {
 
         // Write out the entries for each source file.
         let sources = self.sources
-        let machineCodeObjects = try self.machineCodeObjects
-        let bitcodeObjects = try self.bitcodeObjects
+        let objects = try self.objects
+        let ltoEnabled = self.buildParameters.linkTimeOptimizationMode != nil
+        let objectKey = ltoEnabled ? "llvm-bc" : "object"
 
         for idx in 0..<sources.count {
             let source = sources[idx]
-            let machineCodeObject = machineCodeObjects[idx]
-            let bitcodeObject = bitcodeObjects[idx]
+            let object = objects[idx]
 
             let sourceFileName = source.basenameWithoutExt
             let partialModulePath = self.tempsPath.appending(component: sourceFileName + "~partial.swiftmodule")
@@ -794,11 +784,9 @@ public final class SwiftTargetBuildDescription {
                 // FIXME: Need to record this deps file for processing it later.
             }
 
-
             content +=
                 #"""
-                    "object": "\#(machineCodeObject._nativePathString(escaped: true))",
-                    "llvm-bc": "\#(bitcodeObject._nativePathString(escaped: true))",
+                    "\#(objectKey)": "\#(object._nativePathString(escaped: true))",
                     "swiftmodule": "\#(partialModulePath._nativePathString(escaped: true))",
                     "swift-dependencies": "\#(swiftDepsPath._nativePathString(escaped: true))"
                   }\#((idx + 1) < sources.count ? "," : "")
diff --git a/Sources/CoreCommands/Options.swift b/Sources/CoreCommands/Options.swift
@@ -470,6 +470,13 @@ public struct BuildOptions: ParsableArguments {
     )
     public var testEntryPointPath: AbsolutePath?
 
+    /// The lto mode to use if any.
+    @Option(
+        name: .customLong("experimental-lto-mode"),
+        help: .hidden
+    )
+    public var linkTimeOptimizationMode: LinkTimeOptimizationMode?
+
     // @Flag works best when there is a default value present
     // if true, false aren't enough and a third state is needed
     // nil should not be the goto. Instead create an enum
@@ -484,6 +491,11 @@ public struct BuildOptions: ParsableArguments {
         case warn
         case error
     }
+
+    public enum LinkTimeOptimizationMode: String, Codable, ExpressibleByArgument {
+        case full
+        case thin
+    }
 }
 
 public struct LinkerOptions: ParsableArguments {
diff --git a/Sources/CoreCommands/SwiftTool.swift b/Sources/CoreCommands/SwiftTool.swift
@@ -703,7 +703,8 @@ public final class SwiftTool {
                 testEntryPointPath: options.build.testEntryPointPath,
                 explicitTargetDependencyImportCheckingMode: options.build.explicitTargetDependencyImportCheck.modeParameter,
                 linkerDeadStrip: options.linker.linkerDeadStrip,
-                verboseOutput: self.logLevel <= .info
+                verboseOutput: self.logLevel <= .info,
+                linkTimeOptimizationMode: options.build.linkTimeOptimizationMode?.buildParameter
             )
         })
     }()
@@ -966,6 +967,17 @@ extension BuildOptions.TargetDependencyImportCheckingMode {
     }
 }
 
+extension BuildOptions.LinkTimeOptimizationMode {
+    fileprivate var buildParameter: BuildParameters.LinkTimeOptimizationMode? {
+        switch self {
+        case .full:
+            return .full
+        case .thin:
+            return .thin
+        }
+    }
+}
+
 extension Basics.Diagnostic {
     public static func mutuallyExclusiveArgumentsError(arguments: [String]) -> Self {
         .error(arguments.map { "'\($0)'" }.spm_localizedJoin(type: .conjunction) + " are mutually exclusive")
diff --git a/Sources/SPMBuildCore/BuildParameters.swift b/Sources/SPMBuildCore/BuildParameters.swift
@@ -26,6 +26,11 @@ public struct BuildParameters: Encodable {
         case auto
     }
 
+    public enum LinkTimeOptimizationMode: String, Encodable {
+        case full = "llvm-full"
+        case thin = "llvm-thin"
+    }
+
     /// Represents the debugging strategy.
     ///
     /// Swift binaries requires the swiftmodule files in order for lldb to work.
@@ -219,6 +224,8 @@ public struct BuildParameters: Encodable {
 
     public var verboseOutput: Bool
 
+    public var linkTimeOptimizationMode: LinkTimeOptimizationMode?
+
     public init(
         dataPath: AbsolutePath,
         configuration: BuildConfiguration,
@@ -247,7 +254,8 @@ public struct BuildParameters: Encodable {
         explicitTargetDependencyImportCheckingMode: TargetDependencyImportCheckingMode = .none,
         linkerDeadStrip: Bool = true,
         colorizedOutput: Bool = false,
-        verboseOutput: Bool = false
+        verboseOutput: Bool = false,
+        linkTimeOptimizationMode: LinkTimeOptimizationMode?
     ) throws {
         let triple = try destinationTriple ?? .getHostTriple(usingSwiftCompiler: toolchain.swiftCompilerPath)
 
@@ -288,6 +296,7 @@ public struct BuildParameters: Encodable {
         self.linkerDeadStrip = linkerDeadStrip
         self.colorizedOutput = colorizedOutput
         self.verboseOutput = verboseOutput
+        self.linkTimeOptimizationMode = linkTimeOptimizationMode
     }
 
     public func withDestination(_ destinationTriple: Triple) throws -> BuildParameters {
@@ -330,7 +339,8 @@ public struct BuildParameters: Encodable {
             explicitTargetDependencyImportCheckingMode: self.explicitTargetDependencyImportCheckingMode,
             linkerDeadStrip: self.linkerDeadStrip,
             colorizedOutput: self.colorizedOutput,
-            verboseOutput: self.verboseOutput
+            verboseOutput: self.verboseOutput,
+            linkTimeOptimizationMode: self.linkTimeOptimizationMode
         )
     }
 
diff --git a/Tests/BuildTests/MockBuildTestHelper.swift b/Tests/BuildTests/MockBuildTestHelper.swift
@@ -87,7 +87,8 @@ func mockBuildParameters(
         canRenameEntrypointFunctionName: canRenameEntrypointFunctionName,
         indexStoreMode: indexStoreMode,
         useExplicitModuleBuild: useExplicitModuleBuild,
-        linkerDeadStrip: linkerDeadStrip
+        linkerDeadStrip: linkerDeadStrip,
+        linkTimeOptimizationMode: nil
     )
 }
 

Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,8 @@ func mockBuildParameters(`
`87`	`87`	`canRenameEntrypointFunctionName: canRenameEntrypointFunctionName,`
`88`	`88`	`indexStoreMode: indexStoreMode,`
`89`	`89`	`useExplicitModuleBuild: useExplicitModuleBuild,`
`90`		`- linkerDeadStrip: linkerDeadStrip`
	`90`	`+ linkerDeadStrip: linkerDeadStrip,`
	`91`	`+ linkTimeOptimizationMode: nil`
`91`	`92`	`)`
`92`	`93`	`}`
`93`	`94`