Stop using llbuild's Swift compiler tool (#6585)

This allows us to take control of these compiler invocations and is a first step towards unifying all the various ways of generating compiler arguments that are currently in `SwiftTargetBuildDescription`.

This PR aims to keep the behavior of the existing tool as far as possible, the only known differences are single quotes instead of double for arguments with spaces and the fact that the output file map will be created eagerly.

resolves #6575

Author: neonichu

IntegrationTests/Tests/IntegrationTests/BasicTests.swift

@@ -215,7 +215,7 @@ final class BasicTests: XCTestCase {
 
             // Check the build.
             let buildOutput = try sh(swiftBuild, "--package-path", packagePath, "-v").stdout
-            XCTAssertMatch(buildOutput, .regex(#"swiftc.* -module-name special_tool .* ".*/more spaces/special tool/some file.swift""#))
+            XCTAssertMatch(buildOutput, .regex(#"swiftc.* -module-name special_tool .* '.*/more spaces/special tool/some file.swift'"#))
             XCTAssertMatch(buildOutput, .contains("Build complete"))
 
             // Verify that the tool exists and works.

Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift

@@ -689,7 +689,7 @@ public final class SwiftTargetBuildDescription {
         self.buildParameters.triple.isDarwin() && self.target.type == .library
     }
 
-    private func writeOutputFileMap() throws -> AbsolutePath {
+    func writeOutputFileMap() throws -> AbsolutePath {
         let path = self.tempsPath.appending("output-file-map.json")
         let masterDepsPath = self.tempsPath.appending("master.swiftdeps")
 

Sources/Build/LLBuildManifestBuilder.swift

@@ -628,7 +628,8 @@ extension LLBuildManifestBuilder {
             otherArguments: try target.compileArguments(),
             sources: target.sources,
             isLibrary: isLibrary,
-            wholeModuleOptimization: self.buildParameters.configuration == .release
+            wholeModuleOptimization: self.buildParameters.configuration == .release,
+            outputFileMapPath: try target.writeOutputFileMap() // FIXME: Eliminate side effect.
         )
     }
 

Sources/LLBuildManifest/BuildManifest.swift

@@ -173,7 +173,8 @@ public struct BuildManifest {
         otherArguments: [String],
         sources: [AbsolutePath],
         isLibrary: Bool,
-        wholeModuleOptimization: Bool
+        wholeModuleOptimization: Bool,
+        outputFileMapPath: AbsolutePath
     ) {
         assert(commands[name] == nil, "already had a command named '\(name)'")
         let tool = SwiftCompilerTool(
@@ -189,7 +190,8 @@ public struct BuildManifest {
             otherArguments: otherArguments,
             sources: sources,
             isLibrary: isLibrary,
-            wholeModuleOptimization: wholeModuleOptimization
+            wholeModuleOptimization: wholeModuleOptimization,
+            outputFileMapPath: outputFileMapPath
         )
         commands[name] = Command(name: name, tool: tool)
     }

Sources/LLBuildManifest/Tools.swift

@@ -226,7 +226,7 @@ public struct SwiftFrontendTool: ToolProtocol {
 
 /// Swift compiler llbuild tool.
 public struct SwiftCompilerTool: ToolProtocol {
-    public static let name: String = "swift-compiler"
+    public static let name: String = "shell"
 
     public static let numThreads: Int = ProcessInfo.processInfo.activeProcessorCount
 
@@ -244,6 +244,7 @@ public struct SwiftCompilerTool: ToolProtocol {
     public var sources: [AbsolutePath]
     public var isLibrary: Bool
     public var wholeModuleOptimization: Bool
+    public var outputFileMapPath: AbsolutePath
 
     init(
         inputs: [Node],
@@ -258,7 +259,8 @@ public struct SwiftCompilerTool: ToolProtocol {
         otherArguments: [String],
         sources: [AbsolutePath],
         isLibrary: Bool,
-        wholeModuleOptimization: Bool
+        wholeModuleOptimization: Bool,
+        outputFileMapPath: AbsolutePath
     ) {
         self.inputs = inputs
         self.outputs = outputs
@@ -273,24 +275,43 @@ public struct SwiftCompilerTool: ToolProtocol {
         self.sources = sources
         self.isLibrary = isLibrary
         self.wholeModuleOptimization = wholeModuleOptimization
+        self.outputFileMapPath = outputFileMapPath
     }
 
-    public func write(to stream: ManifestToolStream) {
-        stream["executable"] = executable
-        stream["module-name"] = moduleName
-        if let moduleAliases {
-            // Format the key and value to pass to -module-alias flag
-            let formatted = moduleAliases.map {$0.key + "=" + $0.value}
-            stream["module-aliases"] = formatted
+    var description: String {
+        return "Compiling Swift Module '\(moduleName)' (\(sources.count) sources)"
+    }
+
+    var arguments: [String] {
+        var arguments = [
+            executable.pathString,
+            "-module-name", moduleName,
+        ]
+        if let moduleAliases = moduleAliases {
+            for (original, alias) in moduleAliases {
+                arguments += ["-module-alias", "\(original)=\(alias)"]
+            }
+        }
+        arguments += [
+            "-incremental",
+            "-emit-dependencies",
+            "-emit-module",
+            "-emit-module-path", moduleOutputPath.pathString,
+            "-output-file-map", outputFileMapPath.pathString,
+        ]
+        if isLibrary {
+            arguments += ["-parse-as-library"]
         }
-        stream["module-output-path"] = moduleOutputPath
-        stream["import-paths"] = [importPath]
-        stream["temps-path"] = tempsPath
-        stream["objects"] = objects
-        stream["other-args"] = otherArguments
-        stream["sources"] = sources
-        stream["is-library"] = isLibrary
-        stream["enable-whole-module-optimization"] = wholeModuleOptimization
-        stream["num-threads"] = Self.numThreads
-     }
+        if wholeModuleOptimization {
+            arguments += ["-whole-module-optimization", "-num-threads", "\(Self.numThreads)"]
+        }
+        arguments += ["-c"] + sources.map { $0.pathString }
+        arguments += ["-I", importPath.pathString]
+        arguments += otherArguments
+        return arguments
+    }
+
+    public func write(to stream: ManifestToolStream) {
+        ShellTool(description: description, inputs: inputs, outputs: outputs, arguments: arguments).write(to: stream)
+    }
 }

Tests/CommandsTests/BuildToolTests.swift

@@ -41,7 +41,13 @@ final class BuildToolTests: CommandsTestCase {
         defer { try! SwiftPM.Package.execute(["clean"], packagePath: packagePath) }
         let (binPathOutput, _) = try execute(["--show-bin-path"], packagePath: packagePath)
         let binPath = try AbsolutePath(validating: binPathOutput.trimmingCharacters(in: .whitespacesAndNewlines))
-        let binContents = try localFileSystem.getDirectoryContents(binPath)
+        let binContents = try localFileSystem.getDirectoryContents(binPath).filter {
+            guard let contents = try? localFileSystem.getDirectoryContents(binPath.appending(component: $0)) else {
+                return true
+            }
+            // Filter directories which only contain an output file map since we didn't build anything for those which is what `binContents` is meant to represent.
+            return contents != ["output-file-map.json"]
+        }
         return BuildResult(binPath: binPath, output: output, binContents: binContents)
     }