Normalize system_architecture strings

Normalize system_architecture to arch-vendor-os form.

Use compiler target strings where available and normalize them to
exactly three components across generic Unix, Emscripten, ESP32,
RP2, and STM32.

Add a shared CMake helper for normalization, keep platform-specific
vendor tags for RP2 and STM32, and extend system_architecture tests
for generic Unix and ESP32.

Signed-off-by: Peter M <petermm@gmail.com>

Author: petermm

CHANGELOG.md

@@ -120,6 +120,7 @@ table.
 ### Fixed
 
 - ESP32: improved sntp sync speed from a cold boot.
+- `erlang:system_info(system_architecture)` now reports normalized `arch-vendor-os` strings
 - Fixed `gen_server` internal messages to match OTP so it works across erlang distribution
 - Utilize reserved `phy_init` partition on ESP32 to store wifi calibration for faster connections.
 - Support for zero count in `lists:duplicate/2`.

CMakeModules/SystemArchitecture.cmake

@@ -0,0 +1,71 @@
+#
+# This file is part of AtomVM.
+#
+# Copyright 2026 Peter M. <petermm@gmail.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+#
+
+function(avm_get_system_architecture_string out_var)
+    set(options)
+    set(one_value_args PLATFORM_VENDOR PLATFORM_OS)
+    cmake_parse_arguments(PARSE_ARGV 1 AVM "${options}" "${one_value_args}" "")
+
+    execute_process(
+        COMMAND ${CMAKE_C_COMPILER} -dumpmachine
+        OUTPUT_VARIABLE avm_raw_system_architecture
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        ERROR_QUIET
+    )
+
+    if (avm_raw_system_architecture STREQUAL "")
+        unset(${out_var} PARENT_SCOPE)
+        return()
+    endif()
+
+    string(REPLACE "-" ";" avm_system_architecture_parts "${avm_raw_system_architecture}")
+    list(LENGTH avm_system_architecture_parts avm_system_architecture_length)
+
+    if (avm_system_architecture_length EQUAL 1)
+        list(GET avm_system_architecture_parts 0 avm_architecture)
+        if (DEFINED AVM_PLATFORM_VENDOR)
+            set(avm_vendor "${AVM_PLATFORM_VENDOR}")
+        else()
+            set(avm_vendor "unknown")
+        endif()
+        set(avm_os "unknown")
+    elseif (avm_system_architecture_length EQUAL 2)
+        list(GET avm_system_architecture_parts 0 avm_architecture)
+        if (DEFINED AVM_PLATFORM_VENDOR)
+            set(avm_vendor "${AVM_PLATFORM_VENDOR}")
+        else()
+            set(avm_vendor "unknown")
+        endif()
+        list(GET avm_system_architecture_parts 1 avm_os)
+    else()
+        list(GET avm_system_architecture_parts 0 avm_architecture)
+        list(GET avm_system_architecture_parts 1 avm_vendor)
+        if (DEFINED AVM_PLATFORM_VENDOR AND (avm_vendor STREQUAL "none" OR avm_vendor STREQUAL "unknown"))
+            set(avm_vendor "${AVM_PLATFORM_VENDOR}")
+        endif()
+
+        list(REMOVE_AT avm_system_architecture_parts 0 1)
+        string(REPLACE ";" "_" avm_os "${avm_system_architecture_parts}")
+    endif()
+
+    if (DEFINED AVM_PLATFORM_OS)
+        set(avm_os "${AVM_PLATFORM_OS}")
+    endif()
+
+    string(REPLACE "-" "_" avm_architecture "${avm_architecture}")
+    string(REPLACE "-" "_" avm_vendor "${avm_vendor}")
+    string(REPLACE "-" "_" avm_os "${avm_os}")
+
+    set(${out_var} "${avm_architecture}-${avm_vendor}-${avm_os}" PARENT_SCOPE)
+endfunction()

src/libAtomVM/CMakeLists.txt

@@ -310,6 +310,26 @@ else()
     set(ATOMVM_VERSION ${ATOMVM_BASE_VERSION})
 endif()
 
+set(AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH "${CMAKE_SYSTEM_PROCESSOR}")
+if (AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH STREQUAL "")
+    set(AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH "unknown")
+endif()
+string(REPLACE "-" "_" AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH "${AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH}")
+
+set(AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS "${CMAKE_SYSTEM_NAME}")
+if (AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS STREQUAL "")
+    set(AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS "unknown")
+endif()
+if (NOT CMAKE_SYSTEM_VERSION STREQUAL "")
+    string(APPEND AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS "_${CMAKE_SYSTEM_VERSION}")
+endif()
+string(REPLACE "-" "_" AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS "${AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS}")
+
+if (NOT DEFINED AVM_SYSTEM_ARCHITECTURE_STRING OR AVM_SYSTEM_ARCHITECTURE_STRING STREQUAL "")
+    set(AVM_SYSTEM_ARCHITECTURE_STRING
+        "${AVM_SYSTEM_ARCHITECTURE_FALLBACK_ARCH}-unknown-${AVM_SYSTEM_ARCHITECTURE_FALLBACK_OS}")
+endif()
+
 # Add include to directory where avm_version.h is generated so targets linking
 # libAtomVM can access it
 target_include_directories(libAtomVM PUBLIC ${CMAKE_CURRENT_BINARY_DIR})

src/libAtomVM/nifs.c

@@ -3073,13 +3073,11 @@ static term nif_erlang_system_info(Context *ctx, int argc, term argv[])
         return term_from_int11(sizeof(avm_float_t));
     }
     if (key == SYSTEM_ARCHITECTURE_ATOM) {
-        char buf[128];
-        snprintf(buf, 128, "%s-%s-%s", SYSTEM_NAME, SYSTEM_VERSION, SYSTEM_ARCHITECTURE);
-        size_t len = strnlen(buf, 128);
+        size_t len = sizeof(SYSTEM_ARCHITECTURE_STRING) - 1;
         if (memory_ensure_free_opt(ctx, term_binary_heap_size(len), MEMORY_CAN_SHRINK) != MEMORY_GC_OK) {
             RAISE_ERROR(OUT_OF_MEMORY_ATOM);
         }
-        return term_from_literal_binary((const uint8_t *) buf, len, &ctx->heap, ctx->global);
+        return term_from_literal_binary((const uint8_t *) SYSTEM_ARCHITECTURE_STRING, len, &ctx->heap, ctx->global);
     }
     if (key == ATOMVM_VERSION_ATOM) {
         size_t len = strlen(ATOMVM_VERSION);

src/libAtomVM/version.h.in

@@ -21,4 +21,5 @@
 #define SYSTEM_NAME "${CMAKE_SYSTEM_NAME}"
 #define SYSTEM_VERSION "${CMAKE_SYSTEM_VERSION}"
 #define SYSTEM_ARCHITECTURE "${CMAKE_SYSTEM_PROCESSOR}"
+#define SYSTEM_ARCHITECTURE_STRING "${AVM_SYSTEM_ARCHITECTURE_STRING}"
 #define ATOMVM_VERSION "${ATOMVM_VERSION}"

src/platforms/emscripten/src/CMakeLists.txt

@@ -24,6 +24,9 @@ add_executable(AtomVM main.c)
 
 target_compile_features(AtomVM PUBLIC c_std_11)
 
+include(SystemArchitecture)
+avm_get_system_architecture_string(AVM_SYSTEM_ARCHITECTURE_STRING)
+
 add_subdirectory(../../../libAtomVM libAtomVM)
 target_link_libraries(AtomVM PUBLIC libAtomVM)
 target_compile_options(libAtomVM PUBLIC -O3 -fno-exceptions -fno-rtti -pthread -sINLINING_LIMIT -sUSE_ZLIB=1)

src/platforms/esp32/components/libatomvm/CMakeLists.txt

@@ -24,6 +24,9 @@ idf_component_register(INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/../../../../lib
 # "pedantic" flag should be disabled rather poluting diagnostics with warnings caused from 3rd party
 option(AVM_PEDANTIC_WARNINGS "Pedantic compiler warnings" OFF)
 
+include(SystemArchitecture)
+avm_get_system_architecture_string(AVM_SYSTEM_ARCHITECTURE_STRING PLATFORM_OS esp_idf)
+
 add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/../../../../libAtomVM" "libAtomVM")
 
 # Add directory with platform_atomic.h if we mean to use it

src/platforms/esp32/test/main/test_erl_sources/CMakeLists.txt

@@ -74,6 +74,7 @@ compile_erlang(test_rtc_slow)
 compile_erlang(test_select)
 compile_erlang(test_socket)
 compile_erlang(test_ssl)
+compile_erlang(test_system_architecture)
 compile_erlang(test_time_and_processes)
 compile_erlang(test_twdt)
 compile_erlang(test_tz)
@@ -96,6 +97,7 @@ set(erlang_test_beams
     test_select.beam
     test_socket.beam
     test_ssl.beam
+    test_system_architecture.beam
     test_time_and_processes.beam
     test_twdt.beam
     test_tz.beam

src/platforms/esp32/test/main/test_erl_sources/test_system_architecture.erl

@@ -0,0 +1,34 @@
+%
+% This file is part of AtomVM.
+%
+% Copyright 2026 Peter M. <petermm@gmail.com>
+%
+% Licensed under the Apache License, Version 2.0 (the "License");
+% you may not use this file except in compliance with the License.
+% You may obtain a copy of the License at
+%
+%    http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS,
+% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+% See the License for the specific language governing permissions and
+% limitations under the License.
+%
+% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+%
+
+-module(test_system_architecture).
+-export([start/0]).
+
+start() ->
+    SystemArchitecture = erlang:system_info(system_architecture),
+    ok =
+        case SystemArchitecture of
+            <<"xtensa-esp-esp_idf">> ->
+                ok;
+            <<"riscv32-esp-esp_idf">> ->
+                ok
+        end,
+    nomatch = binary:match(SystemArchitecture, <<"esp_idf-">>),
+    ok.

src/platforms/esp32/test/main/test_main.c

@@ -506,6 +506,12 @@ TEST_CASE("test_time_and_processes", "[test_run]")
     TEST_ASSERT(term_to_int(ret_value) == 6);
 }
 
+TEST_CASE("test_system_architecture", "[test_run]")
+{
+    term ret_value = avm_test_case("test_system_architecture.beam");
+    TEST_ASSERT(ret_value == OK_ATOM);
+}
+
 TEST_CASE("test_tz", "[test_run]")
 {
     term ret_value = avm_test_case("test_tz.beam");