build: Add support for checking an llext build at compile time

This commit adds compile-time checking of the sketch to verify that all
symbols not directly resolved in the sketch are defined in the Zephyr
core. This reuses the 'linked' logic, but defines the llext-specific
symbols only.

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>

Author: pillo79

.gitignore

@@ -6,4 +6,5 @@ llext-edk/
 cflags.txt
 cxxflags.txt
 includes.txt
-provides.ld
+syms-dynamic.ld
+syms-static.ld

extra/build.sh

@@ -91,6 +91,7 @@ done
 
 # Generate the provides.ld file for linked builds
 echo "Generating exported symbol scripts"
+extra/gen_provides.py "${BUILD_DIR}/zephyr/zephyr.elf" -L > ${VARIANT_DIR}/syms-dynamic.ld
 extra/gen_provides.py "${BUILD_DIR}/zephyr/zephyr.elf" -LF \
 	"+kheap_llext_heap" \
 	"+kheap__system_heap" \
@@ -100,6 +101,6 @@ extra/gen_provides.py "${BUILD_DIR}/zephyr/zephyr.elf" -LF \
 	"free=__wrap_free" \
 	"realloc=__wrap_realloc" \
 	"calloc=__wrap_calloc" \
-	"random=__wrap_random" > ${VARIANT_DIR}/provides.ld
+	"random=__wrap_random" > ${VARIANT_DIR}/syms-static.ld
 
 cmake -P extra/gen_arduino_files.cmake $variant

platform.txt

@@ -3,7 +3,7 @@
 # For more info:
 # https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5---3rd-party-Hardware-specification
 
-name=Arduino Zephyr Boards (llext)
+name=Arduino Zephyr Boards
 version=9.9.9
 
 # Compile variables
@@ -55,13 +55,20 @@ upload.extension=elf-zsk.bin
 build.ldscript.path={runtime.platform.path}/variants/_ldscripts
 build.link_command="{compiler.path}{compiler.c.elf.cmd}" "-L{build.path}" "-L{build.variant.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} {build.extra_flags} {build.extra_ldflags} {compiler.zephyr.common_ldflags} --specs=picolibc.specs --specs=nosys.specs {compiler.ldflags} {object_files} -Wl,--start-group "{build.path}/{archive_file}" {compiler.zephyr.extra_ldflags} {compiler.libraries.ldflags} -Wl,--end-group {build.link_args.{build.link_mode}}
 
+build.check_command-dynamic={build.link_command} {build.link_args.check-dynamic} -o "{build.path}/{build.project_name}_check.tmp"
+build.check_command-static=
+build.combine_command={build.link_command} {build.link_args.build-{build.link_mode}} {build.link_args.build-common}
+
 # link_args.* are included by any link_command depending on the link_mode
 build.link_args.dynamic=-e main
-build.link_args.static=-lc -lm -lgcc -L{build.variant.path} -Wl,--wrap=random -Wl,--wrap=calloc -Wl,--wrap=free -Wl,--wrap=malloc -Wl,--wrap=realloc 
+build.link_args.static=-lc -lm -lgcc -L{build.variant.path} -Wl,--wrap=random -Wl,--wrap=calloc -Wl,--wrap=free -Wl,--wrap=malloc -Wl,--wrap=realloc
+
+# link_args.check-* are used to check the build. Only LLEXT needs these to emulate a static build (no -r!).
+build.link_args.check-dynamic="-T{build.variant.path}/syms-dynamic.ld" "-T{build.ldscript.path}/memory-check.ld" "-T{build.ldscript.path}/build-static.ld"
 
 # link_args.build-* are used to create the final binary. -common are added to both static and dynamic.
-build.link_args.build-dynamic="-T{build.ldscript.path}/dynamic.ld" -r
-build.link_args.build-static="-T{build.variant.path}/provides.ld" "-T{build.ldscript.path}/static.ld"
+build.link_args.build-dynamic="-T{build.ldscript.path}/build-dynamic.ld" -r
+build.link_args.build-static="-T{build.variant.path}/syms-static.ld" "-T{build.ldscript.path}/memory-static.ld" "-T{build.ldscript.path}/build-static.ld"
 build.link_args.build-common="-Wl,-Map,{build.path}/{build.project_name}.map" -o "{build.path}/{build.project_name}_debug.elf"
 
 # zsk_args are used to create the final binary with zephyr-sketch-tool
@@ -109,7 +116,9 @@ recipe.S.o.pattern="{compiler.path}{compiler.S.cmd}" {compiler.S.flags} -DARDUIN
 recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} {compiler.ar.extra_flags} "{archive_file_path}" "{object_file}"
 
 ## Combine gc-sections, archives, and objects
-recipe.c.combine.pattern={build.link_command} {build.link_args.build-{build.link_mode}} {build.link_args.build-common}
+recipe.c.combine.1.pattern={build.check_command-{build.link_mode}}
+recipe.c.combine.2.pattern={build.combine_command}
+recipe.c.combine.pattern={build.combine_command}
 recipe.hooks.linking.postlink.1.pattern="{compiler.path}{build.crossprefix}strip" --strip-debug "{build.path}/{build.project_name}_debug.elf" -o "{build.path}/{build.project_name}.elf"
 
 ## Create eeprom

variants/_ldscripts/dynamic.ld renamed to variants/_ldscripts/build-dynamic.ld

@@ -1,18 +1,5 @@
-INCLUDE "provides.ld"
-
-MEMORY
-{
-    /* 16 below compensates for the zsk header that is added before the .bin */
-    FLASH (rx) : ORIGIN = _sketch_start + 16, LENGTH = _sketch_max_size - 16
-    RAM (rwx) : ORIGIN = kheap_llext_heap, LENGTH = kheap_llext_heap_size
-}
-
-PROVIDE(__heap_start = kheap__system_heap);
-PROVIDE(__heap_end = kheap__system_heap + kheap__system_heap_size);
-
 ENTRY(entry_point)
 SECTIONS {
-
     /DISCARD/ : {
         *(.ARM.attributes)
         *(.ARM.attributes.*)

variants/_ldscripts/static.ld renamed to variants/_ldscripts/build-static.ld

@@ -0,0 +1,13 @@
+MEMORY
+{
+    FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x10000000
+    RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x10000000
+}
+
+PROVIDE(__heap_start = 0x40000000);
+PROVIDE(__heap_end = 0x50000000);
+PROVIDE(kheap__system_heap = 0x40000000);
+PROVIDE(kheap__system_heap_size = 0x10000000);
+
+PROVIDE(kheap_llext_heap = 0x60000000);
+PROVIDE(kheap_llext_heap_size = 0x10000000);

variants/_ldscripts/memory-check.ld

@@ -0,0 +1,9 @@
+MEMORY
+{
+    /* 16 below compensates for the zsk header that is added before the .bin */
+    FLASH (rx) : ORIGIN = _sketch_start + 16, LENGTH = _sketch_max_size - 16
+    RAM (rwx) : ORIGIN = kheap_llext_heap, LENGTH = kheap_llext_heap_size
+}
+
+PROVIDE(__heap_start = kheap__system_heap);
+PROVIDE(__heap_end = kheap__system_heap + kheap__system_heap_size);