Merge branch 'lld_orphan' into 'master'

esp_system: enable linking with LLD on RISC-V targets

Closes LLVM-216

See merge request espressif/esp-idf!48712

tools/cmake/project.cmake

@@ -1053,8 +1053,42 @@ macro(project project_name)
         target_link_options(${project_elf} PRIVATE "-Wl,--defsym=IDF_TARGET_${idf_target}=0")
         # Enable map file output
         target_link_options(${project_elf} PRIVATE "-Wl,--Map=${mapfile}")
+        if(CONFIG_COMPILER_USE_LLD)
+            if(CMAKE_C_COMPILER_ID MATCHES "Clang")
+                # The last --ld-path on the link line takes precedence over the
+                # one set in the toolchain file, selecting LLD for the link.
+                # The bare name is looked up in PATH.
+                target_link_options(${project_elf} PRIVATE "--ld-path=ld.lld")
+            else()
+                # GCC has no --ld-path; -fuse-ld=lld makes the driver search
+                # its search paths and PATH for a binary named "ld.lld".
+                target_link_options(${project_elf} PRIVATE "-fuse-ld=lld")
+            endif()
+            # Bare-metal images have no dynamic loader, so PT_GNU_RELRO is
+            # meaningless. LLD enables relro by default and errors out when
+            # relro sections (e.g. TLS .flash.tdata) are not contiguous in the
+            # IDF linker scripts, so disable it.
+            target_link_options(${project_elf} PRIVATE "-Wl,-z,norelro")
+            # Some targets (e.g. esp32s3) use NOLOAD dummy sections that
+            # deliberately overlap other sections' address ranges, because two
+            # memory regions alias the same bus address space. GNU ld skips
+            # NOBITS sections in its overlap check; LLD does not, so disable
+            # the check there.
+            target_link_options(${project_elf} PRIVATE "-Wl,--no-check-sections")
+            set(linker_binary "ld.lld")
+        else()
+            set(linker_binary "${CMAKE_LINKER}")
+        endif()
+        # Report which linker the link will use, with its version banner
+        execute_process(COMMAND ${linker_binary} "--version"
+            OUTPUT_VARIABLE linker_version
+            ERROR_QUIET
+            OUTPUT_STRIP_TRAILING_WHITESPACE)
+        string(REGEX REPLACE "\n.*" "" linker_version "${linker_version}")
+        message(STATUS "Linker: ${linker_binary} (${linker_version})")
+        unset(linker_version)
         # Check if linker supports --no-warn-rwx-segments
-        execute_process(COMMAND ${CMAKE_LINKER} "--no-warn-rwx-segments" "--version"
+        execute_process(COMMAND ${linker_binary} "--no-warn-rwx-segments" "--version"
             RESULT_VARIABLE result
             OUTPUT_QUIET
             ERROR_QUIET)
@@ -1069,6 +1103,7 @@ macro(project project_name)
             # Throw error if orphan sections are found
             target_link_options(${project_elf} PRIVATE "-Wl,--orphan-handling=error")
         endif()
+        unset(linker_binary)
         unset(idf_target)
     endif()
 

tools/cmake/utilities.cmake

@@ -225,7 +225,10 @@ function(preprocess_linker_file cmake_target script_in output_var preserve_suffi
     if(script_parent_name STREQUAL idf_target)
         # Add "../.." directory to include path (e.g. for esp_system component)
         get_filename_component(dir_to_include "${script_parent_dir}" DIRECTORY)
-        set(extra_cflags "-I\"${dir_to_include}\"")
+        # Add esp_system/ld directory to include path for the shared linker
+        # script fragments (e.g. ld.elf.internal.sections)
+        idf_component_get_property(esp_system_dir esp_system COMPONENT_DIR)
+        set(extra_cflags "-I\"${dir_to_include}\" -I\"${esp_system_dir}/ld\"")
     endif()
 
     # Keep comments (-C): historical behavior for cmakev1 linker scripts. It was

tools/cmakev2/project.cmake

@@ -512,8 +512,42 @@ function(__init_project_configuration)
         string(TOUPPER ${target_upper} target_upper)
         # Add this symbol as a hint for esp_idf_size to guess the target name
         list(APPEND link_options "-Wl,--defsym=IDF_TARGET_${target_upper}=0")
+        if(CONFIG_COMPILER_USE_LLD)
+            if(CMAKE_C_COMPILER_ID MATCHES "Clang")
+                # The last --ld-path on the link line takes precedence over the
+                # one set in the toolchain file, selecting LLD for the link.
+                # The bare name is looked up in PATH.
+                list(APPEND link_options "--ld-path=ld.lld")
+            else()
+                # GCC has no --ld-path; -fuse-ld=lld makes the driver search
+                # its search paths and PATH for a binary named "ld.lld".
+                list(APPEND link_options "-fuse-ld=lld")
+            endif()
+            # Bare-metal images have no dynamic loader, so PT_GNU_RELRO is
+            # meaningless. LLD enables relro by default and errors out when
+            # relro sections (e.g. TLS .flash.tdata) are not contiguous in the
+            # IDF linker scripts, so disable it.
+            list(APPEND link_options "-Wl,-z,norelro")
+            # Some targets (e.g. esp32s3) use NOLOAD dummy sections that
+            # deliberately overlap other sections' address ranges, because two
+            # memory regions alias the same bus address space. GNU ld skips
+            # NOBITS sections in its overlap check; LLD does not, so disable
+            # the check there.
+            list(APPEND link_options "-Wl,--no-check-sections")
+            set(linker_binary "ld.lld")
+        else()
+            set(linker_binary "${CMAKE_LINKER}")
+        endif()
+        # Report which linker the link will use, with its version banner
+        execute_process(COMMAND ${linker_binary} "-v"
+            OUTPUT_VARIABLE linker_version
+            ERROR_QUIET
+            OUTPUT_STRIP_TRAILING_WHITESPACE)
+        string(REGEX REPLACE "\n.*" "" linker_version "${linker_version}")
+        message(STATUS "Linker: ${linker_binary} (${linker_version})")
+        unset(linker_version)
         # Check if linker supports --no-warn-rwx-segments
-        execute_process(COMMAND ${CMAKE_LINKER} "--no-warn-rwx-segments" "--version"
+        execute_process(COMMAND ${linker_binary} "--no-warn-rwx-segments" "--version"
             RESULT_VARIABLE result
             OUTPUT_QUIET
             ERROR_QUIET)

tools/cmakev2/utilities.cmake

@@ -1268,12 +1268,17 @@ function(__preprocess_linker_script script_in script_out flags component_include
         # ld.common file, so add the parent directory to the C preprocessor
         # search path. Works for that layout; a component with a different
         # layout, or one that must drop -C, should pass FLAGS instead.
+        # esp_system/ld is added as well so that scripts of other components
+        # can include the shared fragments living there (e.g.
+        # ld.elf.internal.sections).
         set(base_flags "-C")
         get_filename_component(script_parent_dir "${script_in}" DIRECTORY)
         get_filename_component(script_parent_name "${script_parent_dir}" NAME)
         if(script_parent_name STREQUAL idf_target)
             get_filename_component(dir_to_include "${script_parent_dir}" DIRECTORY)
-            string(APPEND base_flags " -I\"${dir_to_include}\"")
+            idf_component_get_property(esp_system_dir esp_system COMPONENT_DIR)
+            string(APPEND base_flags
+                   " -I\"${dir_to_include}\" -I\"${esp_system_dir}/ld\"")
         endif()
     else()
         # Explicit FLAGS replace the whole default set, including -C. config_dir

tools/test_apps/system/.build-test-rules.yml

@@ -51,9 +51,9 @@ tools/test_apps/system/build_tests/trax_esp32s2:
 
 tools/test_apps/system/clang_build_test:
   enable:
-    - if: IDF_TARGET in ["esp32", "esp32s2", "esp32s3", "esp32c2", "esp32c3", "esp32c5", "esp32c6", "esp32h2"]
+    - if: IDF_TARGET in ["esp32", "esp32s2", "esp32s3", "esp32c2", "esp32c3", "esp32c5", "esp32c6", "esp32h2", "esp32p4"]
       temporary: true
-      reason: the other targets are not supported yet, esp32p4 # TODO: IDF-14355
+      reason: the other targets are not supported yet
 
 tools/test_apps/system/cxx_no_except:
   enable:

tools/test_apps/system/clang_build_test/README.md

@@ -1,4 +1,4 @@
-| Supported Targets | ESP32 | ESP32-C2 | ESP32-C3 | ESP32-C5 | ESP32-C6 | ESP32-H2 | ESP32-S2 | ESP32-S3 |
-| ----------------- | ----- | -------- | -------- | -------- | -------- | -------- | -------- | -------- |
+| Supported Targets | ESP32 | ESP32-C2 | ESP32-C3 | ESP32-C5 | ESP32-C6 | ESP32-H2 | ESP32-P4 | ESP32-S2 | ESP32-S3 |
+| ----------------- | ----- | -------- | -------- | -------- | -------- | -------- | -------- | -------- | -------- |
 
 This project is for testing if the application can be built with Clang toolchain.

tools/test_apps/system/clang_build_test/sdkconfig.ci_clang.esp32p4.lld

@@ -0,0 +1,3 @@
+# Build test: link with LLD instead of GNU ld (esp32p4 only)
+CONFIG_IDF_TARGET="esp32p4"
+CONFIG_COMPILER_USE_LLD=y