llvm-libc build: remove all references to libc-hdrgen. (#629)

The 'newhdrgen' tool replaced it some time ago, and that's written in
Python, so it doesn't need to be built separately with host tools at
all.

As of upstream commit e0ae7793fca0c78, the migration is complete, and
the old C++ libc-hdrgen doesn't exist at all any more. So we need to
stop trying to build it – it will break our builds when no such build
target exists.

Author: statham-arm

CMakeLists.txt

@@ -350,25 +350,6 @@ if(LLVM_TOOLCHAIN_C_LIBRARY STREQUAL llvmlibc)
       COMPONENT llvm-toolchain-llvmlibc-configs
     )
 
-    # We need to build libc-hdrgen
-    ExternalProject_Add(
-        libc_hdrgen
-        SOURCE_DIR ${llvmproject_SOURCE_DIR}/llvm
-        DEPENDS ${lib_tool_dependencies}
-        CMAKE_ARGS
-            -DLLVM_ENABLE_RUNTIMES=libc
-            -DLLVM_LIBC_FULL_BUILD=ON
-            -DCMAKE_BUILD_TYPE=Debug
-        STEP_TARGETS build install
-        BUILD_COMMAND ${CMAKE_COMMAND} --build . --target libc-hdrgen
-        INSTALL_COMMAND ${CMAKE_COMMAND} -E true
-        # Always run the build command so that incremental builds are correct.
-        BUILD_ALWAYS TRUE
-        CONFIGURE_HANDLED_BY_BUILD TRUE
-    )
-    ExternalProject_Get_property(libc_hdrgen BINARY_DIR)
-    set(LIBC_HDRGEN ${BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-
     # LLVM libc lacks a configuration for AArch64, but the AArch32 one works
     # fine. However, setting the configuration for both architectures to the
     # arm config directory means the baremetal config.json is never loaded,
@@ -616,7 +597,6 @@ if(NOT PREBUILT_TARGET_LIBRARIES)
         -DENABLE_PARALLEL_LIB_CONFIG=${ENABLE_PARALLEL_LIB_CONFIG}
         -DENABLE_PARALLEL_LIB_BUILD=${ENABLE_PARALLEL_LIB_BUILD}
         -DPARALLEL_LIB_BUILD_LEVELS=${PARALLEL_LIB_BUILD_LEVELS}
-        -DLIBC_HDRGEN=${LIBC_HDRGEN}
         -DFVP_INSTALL_DIR=${FVP_INSTALL_DIR}
         -DENABLE_QEMU_TESTING=${ENABLE_QEMU_TESTING}
         -DENABLE_FVP_TESTING=${ENABLE_FVP_TESTING}

arm-multilib/CMakeLists.txt

@@ -32,7 +32,6 @@ set(ENABLE_VARIANTS "all" CACHE STRING "Semicolon separated list of variants to
 set(C_LIBRARY "picolibc" CACHE STRING "Which C library to use.")
 set_property(CACHE C_LIBRARY PROPERTY STRINGS picolibc newlib llvmlibc)
 set(LLVM_BINARY_DIR "" CACHE PATH "Path to LLVM toolchain build or install root.")
-set(LIBC_HDRGEN "" CACHE PATH "Path to prebuilt lbc-hdrgen if not included in LLVM binaries set by LLVM_BINARY_DIR")
 option(
     ENABLE_QEMU_TESTING
     "Enable tests that use QEMU. This option is ON by default."
@@ -83,7 +82,6 @@ endif()
 # Arguments to pass down to the library projects.
 foreach(arg
     LLVM_BINARY_DIR
-    LIBC_HDRGEN
     FVP_INSTALL_DIR
     FVP_CONFIG_DIR
 )
@@ -108,31 +106,6 @@ endif()
 # Target for any dependencies to build the runtimes project.
 add_custom_target(runtimes-depends)
 
-# If building llvm-libc, ensure libc-hdrgen is available.
-if(C_LIBRARY STREQUAL llvmlibc)
-    if(NOT LIBC_HDRGEN)
-        if(EXISTS ${LLVM_BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-            set(LIBC_HDRGEN ${LLVM_BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-        else()
-            ExternalProject_Add(
-                libc_hdrgen
-                SOURCE_DIR ${llvmproject_SOURCE_DIR}/llvm
-                CMAKE_ARGS
-                    -DLLVM_ENABLE_RUNTIMES=libc
-                    -DLLVM_LIBC_FULL_BUILD=ON
-                    -DCMAKE_BUILD_TYPE=Debug
-                BUILD_COMMAND ${CMAKE_COMMAND} --build . --target libc-hdrgen
-                INSTALL_COMMAND ${CMAKE_COMMAND} -E true
-                CONFIGURE_HANDLED_BY_BUILD TRUE
-            )
-            ExternalProject_Get_property(libc_hdrgen BINARY_DIR)
-            set(LIBC_HDRGEN ${BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-            add_dependencies(runtimes-depends libc_hdrgen)
-        endif()
-    endif()
-    list(APPEND passthrough_dirs "-DLIBC_HDRGEN=${LIBC_HDRGEN}")
-endif()
-
 # Create one target to run all the tests.
 add_custom_target(check-${C_LIBRARY})
 add_custom_target(check-compiler-rt)

arm-runtimes/CMakeLists.txt

@@ -96,7 +96,6 @@ set(ENABLE_LIBC_TESTS ${ENABLE_LIBC_TESTS_def} CACHE BOOL "Enable libc tests (pi
 set(ENABLE_COMPILER_RT_TESTS ${ENABLE_COMPILER_RT_TESTS_def} CACHE BOOL "Enable compiler-rt tests.")
 set(ENABLE_LIBCXX_TESTS ${ENABLE_LIBCXX_TESTS_def} CACHE BOOL "Enable libcxx tests.")
 set(LLVM_BINARY_DIR "" CACHE PATH "Path to LLVM toolchain root to build libraries with")
-set(LIBC_HDRGEN "" CACHE PATH "Path to prebuilt lbc-hdrgen if not included in LLVM binaries set by LLVM_BINARY_DIR")
 
 # Temporary location to collect the libraries as they are built.
 set(TEMP_LIB_DIR "${CMAKE_CURRENT_BINARY_DIR}/tmp_install")
@@ -585,39 +584,14 @@ if(C_LIBRARY STREQUAL llvmlibc)
         -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
     )
 
-    if(LIBC_HDRGEN)
-        # If libc-hdrgen is provided, there is no need to build it,
-        # but a target is still needed to satisfy the dependency.
-        add_custom_target(libc_hdrgen)
-    elseif(EXISTS ${LLVM_BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-        set(LIBC_HDRGEN ${LLVM_BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-        add_custom_target(libc_hdrgen)
-    else()
-        ExternalProject_Add(
-            libc_hdrgen
-            SOURCE_DIR ${llvmproject_SOURCE_DIR}/llvm
-            CMAKE_ARGS
-                -DLLVM_ENABLE_RUNTIMES=libc
-                -DLLVM_LIBC_FULL_BUILD=ON
-                -DCMAKE_BUILD_TYPE=Debug
-            BUILD_COMMAND ${CMAKE_COMMAND} --build . --target libc-hdrgen
-            INSTALL_COMMAND ${CMAKE_COMMAND} -E true
-            CONFIGURE_HANDLED_BY_BUILD TRUE
-        )
-        ExternalProject_Get_property(libc_hdrgen BINARY_DIR)
-        set(LIBC_HDRGEN ${BINARY_DIR}/bin/libc-hdrgen${CMAKE_EXECUTABLE_SUFFIX})
-    endif()
-
     ExternalProject_Add(
         llvmlibc
         SOURCE_DIR ${llvmproject_SOURCE_DIR}/runtimes
         INSTALL_DIR llvmlibc/install
-        DEPENDS libc_hdrgen
         CMAKE_ARGS
         ${compiler_launcher_cmake_args}
         ${common_llvmlibc_cmake_args}
         -DLIBC_TARGET_TRIPLE=${target_triple}
-        -DLIBC_HDRGEN_EXE=${LIBC_HDRGEN}
         -DLIBC_CONFIG_PATH=${LIBC_CFG_DIR}
         -DLIBC_CONF_TIME_64BIT=ON
         -DLLVM_CMAKE_DIR=${LLVM_BINARY_DIR}/lib/cmake/llvm