build-system: create usable debug build

Previously the debug build was to large to flash due to the optimization flag

Author: NickeZ

.ci/ci

@@ -59,6 +59,7 @@ make -j8 bootloader-btc-production
 make -j8 firmware
 make -j8 firmware-btc
 make -j8 factory-setup
+make -j8 firmware-debug
 
 # Disallow some symbols in the final binary that we don't want.
 if arm-none-eabi-nm build/bin/firmware.elf | grep -q "float_to_decimal_common_shortest"; then

CMakeLists.txt

@@ -233,8 +233,9 @@ endif()
 
 # Optimize for size by default
 set(CMAKE_C_FLAGS_RELEASE "-Os -DNDEBUG")
-# Allow gdb extensions if available
-set(CMAKE_C_FLAGS_DEBUG "-Og -ggdb")
+# (-ggdb) Allow gdb extensions if available
+# Optimize debug build for size, optimizing for debug takes to much space.
+set(CMAKE_C_FLAGS_DEBUG "-Os -ggdb")
 set(CMAKE_C_FLAGS_RELWITHDEBINFO "-Os -ggdb -DNDEBUG")
 
 #-----------------------------------------------------------------------------
@@ -321,13 +322,15 @@ string(APPEND CMAKE_C_FLAGS " -Wundef -Wmissing-include-dirs")
 # Disable builtin warning
 string(APPEND CMAKE_C_FLAGS " -Wno-cast-function-type")
 
-# Hardening
-string(APPEND CMAKE_C_FLAGS " -fstack-protector-all")
-if(CMAKE_CROSSCOMPILING)
-  # Path to empty dummy libssp and libssp_shared. '-llibssp -llibssp_shared' is automatically added
-  # with '-fstack-protector-all', but we don't need them as we have our own custom
-  # `__stack_chk_fail`. See https://wiki.osdev.org/Stack_Smashing_Protector.
-  set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -L${CMAKE_CURRENT_SOURCE_DIR}/external/lib/ssp")
+# Enable stack protection on release builds
+if(NOT CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+  string(APPEND CMAKE_C_FLAGS " -fstack-protector-all")
+  if(CMAKE_CROSSCOMPILING)
+    # Path to empty dummy libssp and libssp_shared. '-llibssp -llibssp_shared' is automatically added
+    # with '-fstack-protector-all', but we don't need them as we have our own custom
+    # `__stack_chk_fail`. See https://wiki.osdev.org/Stack_Smashing_Protector.
+    set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -L${CMAKE_CURRENT_SOURCE_DIR}/external/lib/ssp")
+  endif()
 endif()
 
 # Disallow duplicate definitions, which is the default since GCC

Makefile

@@ -26,6 +26,11 @@ build/Makefile:
 	cd build && cmake -DCMAKE_TOOLCHAIN_FILE=arm.cmake ..
 	$(MAKE) -C py/bitbox02
 
+build-debug/Makefile:
+	mkdir -p build-debug
+	cd build-debug && cmake -DCMAKE_TOOLCHAIN_FILE=arm.cmake -DCMAKE_BUILD_TYPE=DEBUG ..
+	$(MAKE) -C py/bitbox02
+
 build-build/Makefile:
 	mkdir -p build-build
 	cd build-build && cmake .. -DCOVERAGE=ON -DSANITIZE_ADDRESS=$(SANITIZE) -DSANITIZE_UNDEFINED=$(SANITIZE)
@@ -41,6 +46,9 @@ build-build-rust-unit-tests/Makefile:
 # Directory for building for "host" machine according to gcc convention
 build: build/Makefile
 
+# Directory for building debug build for "host" machine according to gcc convention
+build-debug: build-debug/Makefile
+
 # Directory for building for "build" machine according to gcc convention
 build-build: build-build/Makefile
 
@@ -50,10 +58,11 @@ build-build: build-build/Makefile
 build-build-rust-unit-tests: build-build-rust-unit-tests/Makefile
 
 firmware: | build
-# Generate python bindings for protobuf for test scripts
 	$(MAKE) -C build firmware.elf
 firmware-btc: | build
 	$(MAKE) -C build firmware-btc.elf
+firmware-debug: | build-debug
+	$(MAKE) -C build-debug firmware.elf
 bootloader: | build
 	$(MAKE) -C build bootloader.elf
 bootloader-development: | build
@@ -128,4 +137,4 @@ prepare-tidy: | build build-build
 	make -C build rust-cbindgen
 	make -C build-build rust-cbindgen
 clean:
-	rm -rf build build-build build-build-rust-unit-tests
+	rm -rf build build-build build-debug build-build-rust-unit-tests

src/CMakeLists.txt

@@ -224,7 +224,11 @@ if(CMAKE_CROSSCOMPILING)
   set(RUST_TARGET_ARCH thumbv7em-none-eabi)
   set(RUST_TARGET_ARCH_DIR ${RUST_TARGET_ARCH})
   set(RUST_TARGET_ARCH_ARG --target ${RUST_TARGET_ARCH})
-  set(RUST_CARGO_FLAGS ${RUST_CARGO_FLAGS} -Zbuild-std=core,alloc -Zbuild-std-features=panic_immediate_abort,optimize_for_size)
+  if(CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+    set(RUST_CARGO_FLAGS ${RUST_CARGO_FLAGS} -Zbuild-std=core,alloc -Zbuild-std-features=optimize_for_size)
+  else()
+    set(RUST_CARGO_FLAGS ${RUST_CARGO_FLAGS} -Zbuild-std=core,alloc -Zbuild-std-features=panic_immediate_abort,optimize_for_size)
+  endif()
 else()
   set(RUST_TARGET_ARCH_DIR .)
 endif()

src/rust/Cargo.toml

@@ -40,11 +40,27 @@ zeroize = "1.7.0"
 # This only affects the .elf output. Debug info is stripped from the final .bin.
 # Paths to source code can still appear in the final bin, as they are part of the panic!() output.
 debug = true
-
+# Optmimize maximally for size, 'z' should produce even less code than 's'
 opt-level = 'z'
+# 1 gives smaller binaries (16 is default in release mode)
 codegen-units = 1
+# Abort on panics in release builds.
 panic = 'abort'
+# LTO gives smaller binaries due to cross-crate optimizations
 lto = true
 
+# Mimic the release profile to save as much space as possible
 [profile.dev]
 opt-level = 'z'
+# Set lto="thin" to get faster builds
+lto = true
+# Enabling debug assertions will increase binary size
+debug-assertions = false
+# Enabling overflow checks will increase binary size
+overflow-checks = false
+# Set to maximally 256 to compile more in parallel
+codegen-units = 1
+# Set to 'abort' to save space
+panic = 'unwind'
+# Set to false to potentially reduce binary size
+incremental = true