[libc][NFC] modularize malloc

libc/cmake/modules/LLVMLibCTargetNameUtils.cmake

@@ -1,4 +1,10 @@
 function(get_fq_target_name local_name target_name_var)
+  # this is the absolute path to the target
+  if (local_name MATCHES "^@.+")
+    string (SUBSTRING ${local_name} 1 -1 local_name)
+    set(${target_name_var} ${local_name} PARENT_SCOPE)
+    return()
+  endif()
   file(RELATIVE_PATH rel_path ${LIBC_SOURCE_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
   string(REPLACE "/" "." fq_name "libc.${rel_path}.${local_name}")
   set(${target_name_var} ${fq_name} PARENT_SCOPE)

libc/src/stdlib/CMakeLists.txt

@@ -323,110 +323,7 @@ add_entrypoint_object(
     .rand_util
 )
 
-if(NOT LIBC_TARGET_OS_IS_GPU)
-  if(LLVM_LIBC_INCLUDE_SCUDO)
-    set(SCUDO_DEPS "")
-
-    include(${LIBC_SOURCE_DIR}/../compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake)
-
-    # scudo distinguishes riscv32 and riscv64, so we need to translate the architecture
-    # set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO ${LIBC_TARGET_ARCHITECTURE})
-    if (LIBC_TARGET_OS_IS_DARWIN AND (LIBC_TARGET_ARCHITECTURE STREQUAL "arm"))
-      set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO arm64)
-    else()
-      set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO ${LIBC_TARGET_ARCHITECTURE})
-    endif()
-    if(LIBC_TARGET_ARCHITECTURE_IS_RISCV64)
-      set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO riscv64)
-    elseif(LIBC_TARGET_ARCHITECTURE_IS_RISCV32)
-      set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO riscv32)
-    endif()
-
-    if(NOT (LIBC_TARGET_ARCHITECTURE_FOR_SCUDO IN_LIST ALL_SCUDO_STANDALONE_SUPPORTED_ARCH))
-      message(FATAL_ERROR "Architecture ${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO} is not supported by SCUDO.
-        Either disable LLVM_LIBC_INCLUDE_SCUDO or change your target architecture.")
-    endif()
-
-    list(APPEND SCUDO_DEPS RTScudoStandalone.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
-        RTScudoStandaloneCWrappers.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO})
-
-    if (COMPILER_RT_BUILD_GWP_ASAN)
-      list(APPEND SCUDO_DEPS
-        RTGwpAsan.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
-        RTGwpAsanBacktraceLibc.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
-        RTGwpAsanSegvHandler.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
-        )
-    endif()
-
-    add_entrypoint_external(
-      malloc
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-    add_entrypoint_external(
-      calloc
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-    add_entrypoint_external(
-      realloc
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-    add_entrypoint_external(
-      aligned_alloc
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-    add_entrypoint_external(
-      free
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-    add_entrypoint_external(
-      mallopt
-      DEPENDS
-        ${SCUDO_DEPS}
-    )
-  else()
-    # Only use freelist malloc for baremetal targets.
-    add_entrypoint_object(
-      freelist_malloc
-      SRCS
-        freelist_malloc.cpp
-      HDRS
-        malloc.h
-      DEPENDS
-        libc.src.__support.freelist_heap
-    )
-    get_target_property(freelist_malloc_is_skipped libc.src.stdlib.freelist_malloc "SKIPPED")
-    if(LIBC_TARGET_OS_IS_BAREMETAL AND NOT freelist_malloc_is_skipped)
-      add_entrypoint_object(
-        malloc
-        ALIAS
-        DEPENDS
-          .freelist_malloc
-      )
-    else()
-      add_entrypoint_external(
-        malloc
-      )
-    endif()
-
-    add_entrypoint_external(
-      free
-    )
-    add_entrypoint_external(
-      calloc
-    )
-    add_entrypoint_external(
-      realloc
-    )
-    add_entrypoint_external(
-      aligned_alloc
-    )
-  endif()
-endif()
+add_subdirectory(allocator)
 
 if(NOT LLVM_LIBC_FULL_BUILD)
   return()

libc/src/stdlib/allocator/CMakeLists.txt

@@ -0,0 +1,34 @@
+if(LIBC_TARGET_OS_IS_GPU)
+  message(STATUS "Skipping allocators for GPU targets.")
+  return()
+endif()
+
+# TODO: we should really use option to dispatch the allocator. Currently, there are
+# other behaviors control the allocator selection. We simulate the existing behavior
+# prior to the modularization of allocator but this should be cleaned up.
+
+if(LLVM_LIBC_INCLUDE_SCUDO)
+  set(DEFAULT_ALLOCATOR_VARIANT "scudo")
+elseif(LIBC_TARGET_OS_IS_BAREMETAL)
+  set(DEFAULT_ALLOCATOR_VARIANT "freelist")
+else()
+  set(DEFAULT_ALLOCATOR_VARIANT "external")
+endif()
+
+set(LIBC_ALLOCATOR_VARIANT ${DEFAULT_ALLOCATOR_VARIANT} CACHE STRING
+  "The allocator variant to use. Options are: scudo, freelist, external.")
+
+message(STATUS "Using ${LIBC_ALLOCATOR_VARIANT} allocator.")
+
+if (LIBC_ALLOCATOR_VARIANT STREQUAL "scudo")
+  if (NOT LLVM_LIBC_INCLUDE_SCUDO)
+    message(FATAL_ERROR "SCUDO allocator is not enabled.")
+  endif()
+  add_subdirectory(scudo)
+elseif (LIBC_ALLOCATOR_VARIANT STREQUAL "freelist")
+  add_subdirectory(freelist)
+elseif (LIBC_ALLOCATOR_VARIANT STREQUAL "external")
+  add_subdirectory(external)
+else()
+  message(FATAL_ERROR "Unknown allocator variant: ${LIBC_ALLOCATOR_VARIANT}")
+endif()

libc/src/stdlib/allocator/external/CMakeLists.txt

@@ -0,0 +1,15 @@
+add_entrypoint_external(
+  @libc.src.stdlib.malloc
+)
+add_entrypoint_external(
+  @libc.src.stdlib.free
+)
+add_entrypoint_external(
+  @libc.src.stdlib.calloc
+)
+add_entrypoint_external(
+  @libc.src.stdlib.realloc
+)
+add_entrypoint_external(
+  @libc.src.stdlib.aligned_alloc
+)

libc/src/stdlib/allocator/freelist/CMakeLists.txt

@@ -0,0 +1,32 @@
+# Only use freelist malloc for baremetal targets.
+add_entrypoint_object(
+  @libc.src.stdlib.freelist_malloc
+  SRCS
+    freelist_malloc.cpp
+  HDRS
+    malloc.h
+  DEPENDS
+    libc.src.__support.freelist_heap
+)
+
+get_target_property(freelist_malloc_is_skipped libc.src.stdlib.freelist_malloc "SKIPPED")
+
+add_entrypoint_object(
+    @libc.src.stdlib.malloc
+    ALIAS
+    DEPENDS
+      .freelist_malloc
+)
+
+add_entrypoint_external(
+  @libc.src.stdlib.free
+)
+add_entrypoint_external(
+  @libc.src.stdlib.calloc
+)
+add_entrypoint_external(
+  @libc.src.stdlib.realloc
+)
+add_entrypoint_external(
+  @libc.src.stdlib.aligned_alloc
+)

libc/src/stdlib/allocator/scudo/CMakeLists.txt

@@ -0,0 +1,66 @@
+set(SCUDO_DEPS "")
+
+include(${LIBC_SOURCE_DIR}/../compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake)
+
+# scudo distinguishes riscv32 and riscv64, so we need to translate the architecture
+# set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO ${LIBC_TARGET_ARCHITECTURE})
+if (LIBC_TARGET_OS_IS_DARWIN AND (LIBC_TARGET_ARCHITECTURE STREQUAL "arm"))
+  set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO arm64)
+else()
+  set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO ${LIBC_TARGET_ARCHITECTURE})
+endif()
+  if(LIBC_TARGET_ARCHITECTURE_IS_RISCV64)
+    set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO riscv64)
+  elseif(LIBC_TARGET_ARCHITECTURE_IS_RISCV32)
+    set(LIBC_TARGET_ARCHITECTURE_FOR_SCUDO riscv32)
+endif()
+
+if(NOT (LIBC_TARGET_ARCHITECTURE_FOR_SCUDO IN_LIST ALL_SCUDO_STANDALONE_SUPPORTED_ARCH))
+  message(FATAL_ERROR "Architecture ${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO} is not supported by SCUDO.
+    Either disable LLVM_LIBC_INCLUDE_SCUDO or change your target architecture.")
+endif()
+
+list(APPEND SCUDO_DEPS RTScudoStandalone.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
+  RTScudoStandaloneCWrappers.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO})
+
+if (COMPILER_RT_BUILD_GWP_ASAN)
+  list(APPEND SCUDO_DEPS
+    RTGwpAsan.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
+    RTGwpAsanBacktraceLibc.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
+    RTGwpAsanSegvHandler.${LIBC_TARGET_ARCHITECTURE_FOR_SCUDO}
+  )
+endif()
+
+add_entrypoint_external(
+  @libc.src.stdlib.malloc
+  DEPENDS
+    ${SCUDO_DEPS}
+)
+
+add_entrypoint_external(
+  @libc.src.stdlib.calloc
+  DEPENDS
+    ${SCUDO_DEPS}
+)
+
+add_entrypoint_external(
+  @libc.src.stdlib.realloc
+  DEPENDS
+    ${SCUDO_DEPS}
+)
+
+add_entrypoint_external(
+  @libc.src.stdlib.aligned_alloc
+  DEPENDS
+    ${SCUDO_DEPS}
+)
+add_entrypoint_external(
+  @libc.src.stdlib.free
+  DEPENDS
+    ${SCUDO_DEPS}
+)
+add_entrypoint_external(
+  @libc.src.stdlib.mallopt
+  DEPENDS
+    ${SCUDO_DEPS}
+)