fix(esp_rom): posixpath.join ESP_ROM_ELF_DIR when generating gdb symbols

ESP_ROM_ELF_DIR from the Windows export scripts often has no trailing
separator. Concatenating it with the ROM ELF filename produced
.../20241011esp32c3_rev101_rom.elf. Use posixpath.join so GDB always
gets a POSIX path with a slash.

Closes https://github.com/espressif/esp-idf/issues/18418

components/esp_rom/gen_gdbinit.py

@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: Apache-2.0
 import json
 import os
+import posixpath
 import sys
 from textwrap import indent
 
@@ -46,10 +47,11 @@ def generate_gdbinit_rom_add_symbols(target: str) -> str:
     for i, k in enumerate(roms[target], 1):
         indent_str = base_ident * i
         rom_file = f'{target}_rev{k["rev"]}_rom.elf'
+        rom_path = posixpath.join(rom_elfs_dir, rom_file)
         build_date_addr = int(k['build_date_str_addr'], base=16)
         r.append(indent(f'# if $_streq((char *) {hex(build_date_addr)}, "{k["build_date_str"]}")', indent_str))
         r.append(indent(get_rom_if_condition_str(build_date_addr, k['build_date_str']), indent_str))
-        r.append(indent(f'add-symbol-file {rom_elfs_dir}{rom_file}', indent_str + base_ident))
+        r.append(indent(f'add-symbol-file {rom_path}', indent_str + base_ident))
         r.append(indent('else', indent_str))
         if i == len(roms[target]):
             # In case no one known ROM ELF fits - print warning

components/esp_rom/test_esp_rom.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
+import importlib.util
 import json
 import os
 
@@ -54,3 +55,36 @@ def test_roms_validate_build_date() -> None:
             build_date_str = get_string_from_elf_by_addr(rom_file, int(k['build_date_str_addr'], base=16))
             assert len(build_date_str) == 11
             assert build_date_str == k['build_date_str']
+
+
+def test_gen_gdbinit_joins_rom_elf_dir() -> None:
+    module_path = os.path.join(os.path.dirname(ROMS_JSON), 'gen_gdbinit.py')
+    spec = importlib.util.spec_from_file_location('gen_gdbinit', module_path)
+    assert spec is not None and spec.loader is not None
+    gen_gdbinit = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(gen_gdbinit)
+
+    rom_dir = '/tmp/esp-rom-elfs/20241011'
+    old = os.environ.get('ESP_ROM_ELF_DIR')
+    os.environ['ESP_ROM_ELF_DIR'] = rom_dir
+    try:
+        out = gen_gdbinit.generate_gdbinit_rom_add_symbols('esp32c3')
+    finally:
+        if old is None:
+            os.environ.pop('ESP_ROM_ELF_DIR', None)
+        else:
+            os.environ['ESP_ROM_ELF_DIR'] = old
+
+    assert f'add-symbol-file {rom_dir}/esp32c3_rev' in out
+    assert f'add-symbol-file {rom_dir}esp32c3_rev' not in out
+
+    os.environ['ESP_ROM_ELF_DIR'] = rom_dir + '/'
+    try:
+        out_slash = gen_gdbinit.generate_gdbinit_rom_add_symbols('esp32c3')
+    finally:
+        if old is None:
+            os.environ.pop('ESP_ROM_ELF_DIR', None)
+        else:
+            os.environ['ESP_ROM_ELF_DIR'] = old
+
+    assert f'add-symbol-file {rom_dir}/esp32c3_rev' in out_slash