WIP: Try to make the firmware build reproducible

.github/workflows/firmware.yml

@@ -1,5 +1,4 @@
 name: Firmware CI Checks
-
 on:
   push
 
@@ -9,54 +8,48 @@ env:
 
 jobs:
   building:
-    name: Building
-    continue-on-error: ${{ matrix.experimental || false }}
+    name: Build ${{ matrix.platform }} (${{ matrix.target }})
     strategy:
       matrix:
-        # All generated code should be running on stable now
-        # TODO: Also test nightly
-        #rust: [nightly, stable]
-        rust: [stable]
-        #include:
-        #  # Nightly is only for reference and allowed to fail
-        #  - rust: nightly
-        #    experimental: true
-        #os:
-        #  # Check compilation works on common OSes
-        #  # (i.e. no path issues)
-        #  # - macOS-latest
-        #  - ubuntu-latest
-        #  - windows-latest
-    runs-on: [ubuntu-latest] #${{ matrix.os }}
+        target: ['debug', 'release']
+        platform: [b1display, c1minimal, ledmatrix]
+    runs-on: [ubuntu-latest]
     steps:
       - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ matrix.rust }}
-          target: thumbv6m-none-eabi
+
+      - name: Setup Rust toolchain
+        run: rustup show
+
       - run: cargo install flip-link
-      - run: cargo build -p ledmatrix
-      - run: cargo build -p b1display
-      - run: cargo build -p c1minimal
-      # TODO: Also build release versions
-      #- run: cargo build --all --release
 
-      - run: |
+      - name: Build release firmware
+        if: ${{ matrix.target }} == 'release'
+        run: |
+            make PLATFORM=${{ matrix.platform }} release
+
+      - name: Build debug firmware
+        if: ${{ matrix.target }} == 'debug'
+        run: |
+            cargo build -p ${{ matrix.platform }}
+
+      - name: Convert to UF2 file
+        run: |
             sudo apt-get update
             sudo apt-get install -y libudev-dev
             cargo install elf2uf2-rs
-            elf2uf2-rs target/thumbv6m-none-eabi/debug/b1display b1display.uf2
-            elf2uf2-rs target/thumbv6m-none-eabi/debug/c1minimal c1minimal.uf2
-            elf2uf2-rs target/thumbv6m-none-eabi/debug/ledmatrix ledmatrix.uf2
+            elf2uf2-rs target/thumbv6m-none-eabi/${{ matrix.target }}/${{ matrix.platform }} ${{ matrix.platform }}.uf2
+
+      - name: Show hash of firmare
+        run: |
+            sha256sum target/thumbv6m-none-eabi/${{ matrix.target }}/${{ matrix.platform }}
+            sha256sum ${{ matrix.platform }}.uf2
 
       - name: Upload Linux tool
         uses: actions/upload-artifact@v3
         with:
-          name: inputmodule_fw
+          name: ${{ matrix.platform }}.uf2
           path: |
-            b1display.uf2
-            c1minimal.uf2
-            ledmatrix.uf2
+            ${{ matrix.platform }}.uf2
 
   linting:
     name: Linting
@@ -65,10 +58,10 @@ jobs:
       - uses: actions/checkout@v3
         with:
           submodules: true
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          components: clippy
-          target: thumbv6m-none-eabi
+
+      - name: Setup Rust toolchain
+        run: rustup show
+
       - run: |
           cargo clippy -p b1display -- --deny=warnings
           cargo clippy -p c1minimal -- --deny=warnings
@@ -81,8 +74,8 @@ jobs:
       - uses: actions/checkout@v3
         with:
           submodules: true
-      - uses: dtolnay/rust-toolchain@stable
-        with:
-          components: rustfmt
-          target: thumbv6m-none-eabi
+
+      - name: Setup Rust toolchain
+        run: rustup show
+
       - run: cargo fmt --all -- --check

Cargo.toml

@@ -44,6 +44,8 @@ incremental = false
 lto = 'fat'
 opt-level = 3
 overflow-checks = false
+# Don't need to strip
+strip = false
 
 # do not optimize proc-macro crates = faster builds from scratch
 [profile.dev.build-override]

Makefile

@@ -0,0 +1,59 @@
+# Makefile to build releases and check build reproducibility
+
+.PHONY: repro release uf2 repro_check
+PLATFORM:=ledmatrix
+RELEASE_BIN:=target/thumbv6m-none-eabi/release/$(PLATFORM)
+TARGET_FOLDER:=target/thumbv6m-none-eabi/release
+FIRST_BIN:=$(PLATFORM)_first
+
+clean:
+	rm -f $(RELEASE_BIN)
+
+# Simple reproducibility check
+# Run clean build twice
+repro:
+	# First build
+	cargo clean
+	$(MAKE) release
+
+	# Back up, so that `cargo clean` won't remove it
+	cp $(RELEASE_BIN) $(FIRST_BIN)
+	# Sleep a bit to make sure timestamps are different
+	sleep 2
+
+	# Second build
+	cargo clean
+	$(MAKE) release
+
+	# Move back into target, so that `cargo clean` can remove it next time
+	mv $(FIRST_BIN) $(TARGET_FOLDER)
+
+	$(MAKE) repro_check
+
+repro_check:
+	# Make sure the username wasn't embedded
+	! strings $(RELEASE_BIN) | grep $(shell whoami)
+
+	# Check that both binaries are equivalent
+	sha256sum $(RELEASE_BIN) $(TARGET_FOLDER)/$(FIRST_BIN)
+	cmp $(RELEASE_BIN) $(TARGET_FOLDER)/$(FIRST_BIN)
+
+release: $(RELEASE_BIN)
+
+uf2: $(RELEASE_BIN)
+	elf2uf2-rs target/thumbv6m-none-eabi/release/$(PLATFORM) $(PLATFORM).uf2
+	ls -lh $(PLATFORM).uf2
+	sha256sum $(PLATFORM).uf2
+
+
+# Build release binary
+# Need to remap paths to avoid local absolute paths being embedded in the binary
+$(RELEASE_BIN):
+	# Need to provide the rustflags defined in .cargo/config.toml again because
+	# setting the environment variable overrides them
+	env \
+		RUSTFLAGS="--remap-path-prefix=$$PWD=. --remap-path-prefix=$$CARGO_HOME=home --remap-path-prefix=$$HOME=home -C link-arg=--nmagic -C link-arg=-Tlink.x -C link-arg=-Tdefmt.x -C linker=flip-link -C inline-threshold=5 -C no-vectorize-loops" \
+		cargo build --release -p $(PLATFORM)
+
+	ls -lh $(RELEASE_BIN)
+	sha256sum $(RELEASE_BIN)

rust-toolchain.toml

@@ -0,0 +1,4 @@
+[toolchain]
+channel = "1.69.0"
+targets = ["thumbv6m-none-eabi"]
+components = ["clippy", "rustfmt"]