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 <[email protected]>

Author: pillo79

.gitignore

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

boards.txt

@@ -447,10 +447,7 @@ portentac33.menu.debug.true.postbuild_debug=-debug
 portentac33.menu.mode.llext=llext
 portentac33.menu.mode.linked=linked
 
-portentac33.menu.mode.linked.build.extra_ldflags=-lc -lm -lgcc -L{build.variant.path} -Wl,--wrap=random -Wl,--wrap=calloc -Wl,--wrap=free -Wl,--wrap=malloc -Wl,--wrap=realloc 
-portentac33.menu.mode.linked.build.llext_link_flags=
-portentac33.menu.mode.linked.build.suffix=_linked
-portentac33.menu.mode.linked.build.ldscript={runtime.platform.path}/variants/_linked/linker_script.ld
+portentac33.menu.mode.linked.build.link_mode=linked
 portentac33.menu.mode.linked.upload.extension=bin-zsk.bin
 portentac33.menu.mode.linked.postbuild_mode=-prelinked
 

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 > ${VARIANT_DIR}/syms-llext.ld
 extra/gen_provides.py "${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-linked.ld
 
 cmake -P extra/gen_arduino_files.cmake $variant

extra/package_core.inc

@@ -13,5 +13,4 @@ README.md
 doc/
 cores/
 libraries/
-variants/_llext/
-variants/_linked/
+variants/_ldscripts/

platform.txt

@@ -19,7 +19,7 @@ compiler.path={build.compiler_path}
 compiler.c.cmd={build.crossprefix}gcc
 compiler.c.flags=-g -c {compiler.warning_flags} {compiler.zephyr.macros} "@{compiler.zephyr.cflags_file}" {compiler.zephyr.arch.define} -MMD -mcpu={build.mcu} {build.float-abi} {build.fpu}
 compiler.c.elf.cmd={build.crossprefix}g++
-compiler.c.elf.flags={build.llext_link_flags} -Wl,--gc-sections -mcpu={build.mcu} {build.float-abi} {build.fpu} -std=gnu++17
+compiler.c.elf.flags=-Wl,--gc-sections -mcpu={build.mcu} {build.float-abi} {build.fpu} -std=gnu++17
 compiler.S.cmd={build.crossprefix}g++
 compiler.S.flags=-c -x assembler-with-cpp -mcpu={build.mcu} {build.fpu}
 compiler.cpp.cmd={build.crossprefix}g++
@@ -49,12 +49,26 @@ compiler.zephyr.extra_ldflags=-lstdc++ -lsupc++
 # this can be overriden in boards.txt
 build.extra_flags=
 build.extra_ldflags=
+build.link_mode=llext
 compiler.zephyr=
 
-build.ldscript={runtime.platform.path}/variants/_llext/linker_script.ld
-build.llext_link_flags=-r -e main
-build.extra_extra_ldflags=
-build.suffix=
+build.ldscript.path={runtime.platform.path}/variants/_ldscripts
+build.link_command="{compiler.path}{compiler.c.elf.cmd}" "-L{build.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} {compiler.zephyr.extra_ldflags} {compiler.libraries.ldflags} -Wl,--end-group {build.link_args.{build.link_mode}}
+
+# link_args.* are included by any link_command depending on the link_mode
+build.link_args.llext=-e main
+build.link_args.linked=-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 linked build (no -r!).
+build.link_args.check-llext="-T{build.variant.path}/syms-llext.ld" "-T{build.ldscript.path}/memory-check.ld" "-T{build.ldscript.path}/build-linked.ld"
+# link_args.build-* are used to create the final binary. -common are added to both llext and linked.
+build.link_args.build-llext="-T{build.ldscript.path}/build-llext.ld" -r
+build.link_args.build-linked="-T{build.variant.path}/syms-linked.ld" "-T{build.ldscript.path}/memory-linked.ld" "-T{build.ldscript.path}/build-linked.ld"
+build.link_args.build-common="-Wl,-Map,{build.path}/{build.project_name}.map" -o "{build.path}/{build.project_name}_debug.elf"
+
+build.check_command-llext={build.link_command} {build.link_args.check-llext} -o "{build.path}/{build.project_name}_check.tmp"
+build.check_command-linked=
+build.combine_command={build.link_command} {build.link_args.build-{build.link_mode}} {build.link_args.build-common}
+
 upload.extension=elf-zsk.bin
 postbuild_debug=
 postbuild_mode=
@@ -99,7 +113,9 @@ 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="{compiler.path}{compiler.c.elf.cmd}"  "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} {build.extra_flags} {build.extra_ldflags} {compiler.zephyr.common_ldflags} "-T{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" --specs=picolibc.specs --specs=nosys.specs {compiler.ldflags} -o "{build.path}/{build.project_name}_debug.elf" {object_files} -Wl,--start-group "{build.path}/{archive_file}" {compiler.zephyr} {compiler.zephyr.extra_ldflags} {compiler.libraries.ldflags} -Wl,--end-group
+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/_linked/linker_script.ld renamed to variants/_ldscripts/build-linked.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/_llext/linker_script.ld renamed to variants/_ldscripts/build-llext.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);