Modernize rpi-5 build

Tools/Toolsets/rpi-5-elf.json

@@ -0,0 +1,19 @@
+{
+  "schemaVersion": "1.0",
+  "swiftCompiler": {
+    "extraCLIOptions": [
+      "-Xfrontend", "-disable-stack-protector",
+      "-Xfrontend", "-function-sections",
+      "-enable-experimental-feature", "Embedded",
+      "-Xfrontend", "-mergeable-symbols",
+      "-Xclang-linker", "-fuse-ld=lld",
+      "-Xclang-linker", "-nostdlib"
+    ]
+  },
+  "linker": {
+    "extraCLIOptions": [
+      "-T", "Sources/Support/linkerscript.ld",
+      "--unresolved-symbols=ignore-in-object-files"
+    ]
+  }
+}

rpi-4b-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 --configuration release --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 --configuration release --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-4b-blink/Package.swift

@@ -3,33 +3,19 @@
 import PackageDescription
 
 let package = Package(
-  name: "RPi4B-Blink",
-  platforms: [
-    .macOS(.v14)
-  ],
+  name: "rpi-4b-blink",
   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")
+    .package(url: "https://github.com/apple/swift-mmio.git", branch: "main")
   ],
   targets: [
-    .target(
-      name: "MainApp",
+    .executableTarget(
+      name: "Application",
       dependencies: [
-        .product(name: "MMIO", package: "swift-mmio")
-      ],
-      swiftSettings: [
-        .enableExperimentalFeature("Embedded"),
-        .unsafeFlags(["-Xfrontend", "-function-sections"]),
-      ]
-    ),
+        .product(name: "MMIO", package: "swift-mmio"),
+        "Support",
+      ]),
     .target(name: "Support"),
-
-  ]
-)
+  ])

rpi-4b-blink/README.md

@@ -6,19 +6,16 @@
 
 - A Raspberry Pi 4B board
 - An SD Card, with a Raspberry Pi OS installed (this way, we don't need to create the configuration files from scratch). You may backup `kernel8.img` and `config.txt` if you need the Linux install later, since we will change these files.
-- LLVM installed (`brew install llvm`) and added to PATH. This is needed to convert the resulted ELF file to binary image format using `llvm-objcopy`.
 
 ## How to build and run this example:
 
 - Make sure you have a recent nightly Swift toolchain that has Embedded Swift support.
 - Build the program, then copy the kernel image to the SD card.
 ``` console
 $ cd rpi-4b-blink
-$ export TOOLCHAINS='<toolchain-identifier>' # Your Swift nightly toolchain identifier
 $ make
-$ cp kernel8.img /Volumes/bootfs
+$ cp .build/release/Application.bin /Volumes/bootfs/kernel8.img
 ```
 - If your original OS is not 64-bit, make sure to set `arm_64bit=1` in `config.txt`.
 - Place the SD card in your Raspberry Pi 4B, and connect it to power.
 - After the boot sequence, the green (ACT) led will start blinking in a regular pattern.
-

rpi-4b-blink/Sources/MainApp/MainApp.swift → rpi-4b-blink/Sources/Application/Application.swift

@@ -2,14 +2,15 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2024 Apple Inc. and the Swift project authors.
+// 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
 //
 //===----------------------------------------------------------------------===//
 
 import MMIO
+import Support
 
 @Register(bitWidth: 32)
 struct GPSET1 {
@@ -66,17 +67,19 @@ func ledOff() {
   }
 }
 
-@main
-struct Main {
+func delay() {
+  for _ in 1..<1_000_000 { nop() }
+}
 
+@main
+struct Application {
   static func main() {
     setLedOutput()
-
     while true {
       ledOn()
-      for _ in 1..<100000 {}  // just a delay
+      delay()
       ledOff()
-      for _ in 1..<100000 {}  // just a delay
+      delay()
     }
   }
 }

rpi-4b-blink/Sources/Support/include/Support.h

@@ -0,0 +1,16 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+
+static inline __attribute((always_inline)) void nop() {
+    asm volatile("nop");
+}

rpi-5-blink/link.ld → rpi-4b-blink/Sources/Support/linkerscript.ld

@@ -1,6 +1,7 @@
 SECTIONS
 {
-    . = 0x80000;     /* Kernel load address for AArch64 */
+    /* Kernel load address for AArch64 */
+    . = 0x80000;
     .text : { KEEP(*(.text.boot)) *(.text .text.* .gnu.linkonce.t*) }
     .rodata : { *(.rodata .rodata.* .gnu.linkonce.r*) }
     PROVIDE(_data = .);
@@ -14,6 +15,13 @@ SECTIONS
     }
     _end = .;
 
-   /DISCARD/ : { *(.comment) *(.gnu*) *(.note*) *(.eh_frame*) }
+    /DISCARD/ : {
+        *(.comment)
+        *(.gnu*)
+        *(.note*)
+        *(.eh_frame*)
+        *(.swift_modhash)
+    }
 }
-__bss_size = (__bss_end - __bss_start)>>3;
+
+__bss_size = (__bss_end - __bss_start) >> 3;

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 --configuration release --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 --configuration release --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

@@ -3,33 +3,19 @@
 import PackageDescription
 
 let package = Package(
-  name: "RPi5-Blink",
-  platforms: [
-    .macOS(.v14)
-  ],
+  name: "rpi-5-blink",
   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")
+    .package(url: "https://github.com/apple/swift-mmio.git", branch: "main")
   ],
   targets: [
-    .target(
-      name: "MainApp",
+    .executableTarget(
+      name: "Application",
       dependencies: [
-        .product(name: "MMIO", package: "swift-mmio")
-      ],
-      swiftSettings: [
-        .enableExperimentalFeature("Embedded"),
-        .unsafeFlags(["-Xfrontend", "-function-sections"]),
-      ]
-    ),
+        .product(name: "MMIO", package: "swift-mmio"),
+        "Support",
+      ]),
     .target(name: "Support"),
-
-  ]
-)
+  ])