Merge branch 'feature/clang_toolchain_compat' into 'master'

Build system: minimal changes for clang compatibility

See merge request espressif/esp-idf!15168

components/cbor/CMakeLists.txt

@@ -13,3 +13,8 @@ idf_component_register(SRCS "tinycbor/src/cborencoder_close_container_checked.c"
 
 # for open_memstream.c
 set_source_files_properties(tinycbor/src/open_memstream.c PROPERTIES COMPILE_DEFINITIONS "__linux__")
+
+# workaround for the fact that we are passing -ffreestanding to Clang
+if(CMAKE_C_COMPILER_ID MATCHES "Clang")
+    target_compile_options(${COMPONENT_LIB} PRIVATE "-U __STDC_HOSTED__")
+endif()

components/console/CMakeLists.txt

@@ -6,3 +6,7 @@ idf_component_register(SRCS "commands.c"
                     INCLUDE_DIRS "."
                     REQUIRES vfs
                     PRIV_REQUIRES driver)
+
+if(CMAKE_C_COMPILER_ID MATCHES "GNU")
+    set_source_files_properties(argtable3/argtable3.c PROPERTIES COMPILE_FLAGS -Wno-clobbered)
+endif()

components/console/argtable3/argtable3.c

@@ -30,8 +30,6 @@
 
 #include "argtable3.h"
 
-#pragma GCC diagnostic ignored "-Wclobbered"
-
 /*******************************************************************************
  * This file is part of the argtable3 library.
  *

components/console/component.mk

@@ -1,2 +1,4 @@
 COMPONENT_ADD_INCLUDEDIRS := .
 COMPONENT_SRCDIRS := linenoise argtable3 .
+
+argtable3/argtable3.o: CFLAGS += -Wno-clobbered

components/esp_common/project_include.cmake

@@ -1,8 +1,12 @@
 #
 # Warn if the toolchain version doesn't match
 #
-if(NOT ${target} STREQUAL "linux")
+if(NOT (${target} STREQUAL "linux" OR CMAKE_C_COMPILER_ID MATCHES "Clang"))
     get_expected_ctng_version(expected_toolchain expected_gcc)
     gcc_version_check("${expected_gcc}")
     crosstool_version_check("${expected_toolchain}")
 endif()
+
+if(NOT ${target} STREQUAL "linux" AND CMAKE_C_COMPILER_ID MATCHES "Clang")
+    message(WARNING "Building ESP-IDF with clang is an experimental feature and is not yet officially supported.")
+endif()

components/esp_system/panic.c

@@ -399,7 +399,7 @@ void IRAM_ATTR __attribute__((noreturn, no_sanitize_undefined)) panic_abort(cons
 #endif
 #endif
 
-    *((int *) 0) = 0; // NOLINT(clang-analyzer-core.NullDereference) should be an invalid operation on targets
+    *((volatile int *) 0) = 0; // NOLINT(clang-analyzer-core.NullDereference) should be an invalid operation on targets
     while (1);
 }
 

components/newlib/syscalls.c

@@ -94,8 +94,10 @@ int _fstat_r (struct _reent *r, int fd, struct stat *st)
  * doesn't have the same signature as the original function.
  * Disable type mismatch warnings for this reason.
  */
+#if defined(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wattribute-alias"
+#endif
 
 int _open_r(struct _reent *r, const char * path, int flags, int mode)
     __attribute__((weak,alias("syscall_not_implemented")));
@@ -133,7 +135,9 @@ int _kill_r(struct _reent *r, int pid, int sig)
 void _exit(int __status)
     __attribute__((alias("syscall_not_implemented_aborts")));
 
+#if defined(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic pop
+#endif
 
 /* Similar to syscall_not_implemented, but not taking struct _reent argument */
 int system(const char* str)

components/spi_flash/CMakeLists.txt

@@ -55,5 +55,9 @@ idf_component_register(SRCS "${srcs}"
                     LDFRAGMENTS linker.lf)
 
 # Avoid cache miss by unexpected inlineing when built by -Os
-set_source_files_properties(${cache_srcs} PROPERTIES COMPILE_FLAGS
-    "-fno-inline-functions -fno-inline-small-functions -fno-inline-functions-called-once")
+set_source_files_properties(${cache_srcs} PROPERTIES COMPILE_FLAGS "-fno-inline-functions")
+if(CMAKE_C_COMPILER_ID MATCHES "GNU")
+    # These flags are GCC specific
+    set_property(SOURCE ${cache_srcs} APPEND_STRING PROPERTY COMPILE_FLAGS
+        " -fno-inline-small-functions -fno-inline-functions-called-once")
+endif()

components/spi_flash/include/spi_flash_chip_generic.h

@@ -408,4 +408,4 @@ esp_err_t spi_flash_chip_generic_suspend_cmd_conf(esp_flash_t *chip);
 esp_err_t spi_flash_chip_generic_read_unique_id_none(esp_flash_t *chip, uint64_t* flash_unique_id);
 
 /// Default timeout configuration used by most chips
-const flash_chip_op_timeout_t spi_flash_chip_generic_timeout;
+extern const flash_chip_op_timeout_t spi_flash_chip_generic_timeout;

components/spiffs/CMakeLists.txt

@@ -10,4 +10,6 @@ idf_component_register(SRCS "esp_spiffs.c"
                     REQUIRES spi_flash
                     PRIV_REQUIRES bootloader_support esptool_py)
 
-set_source_files_properties(spiffs/src/spiffs_nucleus.c PROPERTIES COMPILE_FLAGS -Wno-stringop-truncation)
+if(CMAKE_C_COMPILER_ID MATCHES "GNU")
+    set_source_files_properties(spiffs/src/spiffs_nucleus.c PROPERTIES COMPILE_FLAGS -Wno-stringop-truncation)
+endif()