Modernize rpi-5 build

Updates the rpi-5-blink example to link using SwiftPM and use a
toolset.json.

Author: rauhul

Tools/Toolsets/rpi-5-elf.json

@@ -0,0 +1,18 @@
+{
+  "schemaVersion": "1.0",
+  "swiftCompiler": {
+    "extraCLIOptions": [
+      "-Xfrontend", "-disable-stack-protector",
+      "-Xfrontend", "-function-sections",
+      "-enable-experimental-feature", "Embedded",
+      "-Xfrontend", "-mergeable-symbols",
+      "-Xclang-linker", "-nostdlib"
+    ]
+  },
+  "linker": {
+    "extraCLIOptions": [
+      "-T", "Sources/Support/linkerscript.ld",
+      "--unresolved-symbols=ignore-in-object-files"
+    ]
+  }
+}

rpi-4b-blink/Makefile

@@ -1,4 +1,4 @@
-SWIFT_EXEC ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f swift; else which swift; fi)
+SWIFT_EXEC ?= swift
 CLANG ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f clang; else which clang; fi)
 LLVM_OBJCOPY ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f llvm-objcopy; else which llvm-objcopy; fi)
 
@@ -16,7 +16,7 @@ kernel8.img: kernel8.elf
 
 kernel8.elf: $(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o link.ld
 	@echo "🔗 Linking with clang..."
-	$(CLANG) --target=aarch64-elf -o kernel8.elf $< $^ -fuse-ld=lld -nostdlib -Wl,--unresolved-symbols=ignore-in-object-files -Wl,-T ./link.ld
+	$(CLANG) --target=aarch64-elf -o kernel8.elf $< $^ -fuse-ld=lld -nostdlib -Wl,--unresolved-symbols=ignore-in-object-files -Wl,-T ./link.ld -###
 	@echo ""
 
 $(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o: 

rpi-5-blink/Makefile

@@ -1,28 +1,47 @@
-SWIFT_EXEC ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f swift; else which swift; fi)
-CLANG ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f clang; else which clang; fi)
-LLVM_OBJCOPY ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f llvm-objcopy; else which llvm-objcopy; fi)
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the Swift open source project
+##
+## Copyright (c) 2025 Apple Inc. and the Swift project authors.
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+##
+##===----------------------------------------------------------------------===##
 
-BUILDROOT := $(shell $(SWIFT_EXEC) build --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector --show-bin-path)
+# Paths
+REPOROOT         := $(shell git rev-parse --show-toplevel)
+TOOLSROOT        := $(REPOROOT)/Tools
+TOOLSET          := $(TOOLSROOT)/Toolsets/rpi-5-elf.json
+LLVM_OBJCOPY     := llvm-objcopy
+SWIFT_BUILD      := swift build
 
-.PHONY: all clean
+# Flags
+ARCH             := aarch64
+TARGET           := $(ARCH)-none-none-elf
+SWIFT_BUILD_ARGS := \
+	--configuration release \
+	--triple $(TARGET) \
+	--toolset $(TOOLSET) \
+	--disable-local-rpath
+BUILDROOT        := $(shell $(SWIFT_BUILD) $(SWIFT_BUILD_ARGS) --show-bin-path)
 
-all: kernel8.img
+.PHONY: build
+build:
+	@echo "building..."
+	$(SWIFT_BUILD) \
+		$(SWIFT_BUILD_ARGS) \
+		--verbose
 
-kernel8.img: kernel8.elf
-	@echo "💾 Converting to binary kernel image with llvm-objcopy..."
-	$(LLVM_OBJCOPY) -O binary kernel8.elf kernel8.img
-	@echo ""
-	@echo "🥳 Done! kernel8.img was saved to this directory."
+	@echo "extracting binary..."
+	$(LLVM_OBJCOPY) \
+		-O binary \
+		"$(BUILDROOT)/Application" \
+		"$(BUILDROOT)/Application.bin" \
 
-kernel8.elf: $(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o link.ld
-	@echo "🔗 Linking with clang..."
-	$(CLANG) --target=aarch64-elf -o kernel8.elf $< $^ -fuse-ld=lld -nostdlib -Wl,--unresolved-symbols=ignore-in-object-files -Wl,-T ./link.ld
-	@echo ""
-
-$(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o: 
-	@echo "🛠️  Building with Swift Package Manager..."
-	$(SWIFT_EXEC) build --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector
-	@echo ""
 
+.PHONY: clean
 clean:
-	rm -rf kernel8.elf kernel8.img .build
+	@echo "cleaning..."
+	@swift package clean
+	@rm -rf .build

rpi-5-blink/Package.swift

@@ -8,28 +8,19 @@ let package = Package(
     .macOS(.v14)
   ],
   products: [
-    .library(
-      name: "MainApp",
-      type: .static,
-      targets: ["MainApp"])
+    .executable(name: "Application", targets: ["Application"])
   ],
   dependencies: [
     .package(
       url: "https://github.com/apple/swift-mmio.git",
       branch: "swift-embedded-examples")
   ],
   targets: [
-    .target(
-      name: "MainApp",
+    .executableTarget(
+      name: "Application",
       dependencies: [
         .product(name: "MMIO", package: "swift-mmio")
-      ],
-      swiftSettings: [
-        .enableExperimentalFeature("Embedded"),
-        .unsafeFlags(["-Xfrontend", "-function-sections"]),
-      ]
-    ),
+      ]),
     .target(name: "Support"),
-
   ]
 )

rpi-5-blink/Sources/MainApp/MainApp.swift renamed to rpi-5-blink/Sources/Application/Application.swift

@@ -41,11 +41,9 @@ func ledOff() {
 }
 
 @main
-struct Main {
-
+struct Application {
   static func main() {
     setLedOutput()
-
     while true {
       ledOn()
       for _ in 1..<100000 {}  // just a delay