[libc] add malloc funcs as external entrypoints

malloc, calloc, realloc, and free are all functions that other libc
functions depend on, but are pulled from external sources, instead of
having an internal implementation. This patch adds a way to include
functions like that as entrypoints in the list of external entrypoints,
and includes the malloc functions using this new path.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D112104

libc/cmake/modules/LLVMLibCLibraryRules.cmake

@@ -36,24 +36,31 @@ function(collect_object_file_deps target result)
     set(${result} ${all_deps} PARENT_SCOPE)
     return()
   endif()
+
+  if(${target_type} STREQUAL ${ENTRYPOINT_EXT_TARGET_TYPE})
+    # It is not possible to recursively extract deps of external dependencies.
+    # So, we just accumulate the direct dep and return.
+    get_target_property(deps ${target} "DEPS")
+    set(${result} ${deps} PARENT_SCOPE)
+    return()
+  endif()
 endfunction(collect_object_file_deps)
 
 # A rule to build a library from a collection of entrypoint objects.
 # Usage:
 #     add_entrypoint_library(
 #       DEPENDS <list of add_entrypoint_object targets>
-#       EXT_DEPS <list of external object targets, no type checking is done>
 #     )
 #
-# NOTE: If one wants an entrypoint to be availabe in a library, then they will
+# NOTE: If one wants an entrypoint to be available in a library, then they will
 # have to list the entrypoint target explicitly in the DEPENDS list. Implicit
 # entrypoint dependencies will not be added to the library.
 function(add_entrypoint_library target_name)
   cmake_parse_arguments(
     "ENTRYPOINT_LIBRARY"
     "" # No optional arguments
     "" # No single value arguments
-    "DEPENDS;EXT_DEPS" # Multi-value arguments
+    "DEPENDS" # Multi-value arguments
     ${ARGN}
   )
   if(NOT ENTRYPOINT_LIBRARY_DEPENDS)
@@ -65,9 +72,9 @@ function(add_entrypoint_library target_name)
   set(all_deps "")
   foreach(dep IN LISTS fq_deps_list)
     get_target_property(dep_type ${dep} "TARGET_TYPE")
-    if(NOT (${dep_type} STREQUAL ${ENTRYPOINT_OBJ_TARGET_TYPE}))
+    if(NOT ((${dep_type} STREQUAL ${ENTRYPOINT_OBJ_TARGET_TYPE}) OR (${dep_type} STREQUAL ${ENTRYPOINT_EXT_TARGET_TYPE})))
       message(FATAL_ERROR "Dependency '${dep}' of 'add_entrypoint_collection' is "
-                          "not an 'add_entrypoint_object' target.")
+                          "not an 'add_entrypoint_object' or 'add_entrypoint_external' target.")
     endif()
     collect_object_file_deps(${dep} recursive_deps)
     list(APPEND all_deps ${recursive_deps})
@@ -78,10 +85,6 @@ function(add_entrypoint_library target_name)
     list(APPEND objects $<TARGET_OBJECTS:${dep}>)
   endforeach(dep)
 
-  foreach(dep IN LISTS ENTRYPOINT_LIBRARY_EXT_DEPS)
-    list(APPEND objects $<TARGET_OBJECTS:${dep}>)
-  endforeach(dep)
-
   add_library(
     ${target_name}
     STATIC

libc/cmake/modules/LLVMLibCObjectRules.cmake

@@ -258,6 +258,36 @@ function(add_entrypoint_object target_name)
 
 endfunction(add_entrypoint_object)
 
+set(ENTRYPOINT_EXT_TARGET_TYPE "ENTRYPOINT_EXT")
+
+# A rule for external entrypoint targets.
+# Usage:
+#     add_entrypoint_external(
+#       <target_name>
+#       DEPENDS <list of dependencies>
+#     )
+function(add_entrypoint_external target_name)
+  cmake_parse_arguments(
+    "ADD_ENTRYPOINT_EXT"
+    "" # No optional arguments
+    "" # No single value arguments
+    "DEPENDS"  # Multi value arguments
+    ${ARGN}
+  )
+  get_fq_target_name(${target_name} fq_target_name)
+  set(entrypoint_name ${target_name})
+
+  add_custom_target(${fq_target_name})
+  set_target_properties(
+    ${fq_target_name}
+    PROPERTIES
+      "ENTRYPOINT_NAME" ${entrypoint_name}
+      "TARGET_TYPE" ${ENTRYPOINT_EXT_TARGET_TYPE}
+      "DEPS" "${ADD_ENTRYPOINT_EXT_DEPENDS}"
+  )
+
+endfunction(add_entrypoint_external)
+
 # Rule build a redirector object file.
 function(add_redirector_object target_name)
   cmake_parse_arguments(

libc/config/linux/x86_64/entrypoints.txt

@@ -228,6 +228,19 @@ if(LLVM_LIBC_FULL_BUILD)
   )
 endif()
 
+if(LLVM_LIBC_INCLUDE_SCUDO)
+  list(APPEND TARGET_LIBC_ENTRYPOINTS
+
+    # stdlib.h external entrypoints
+    libc.src.stdlib.malloc
+    libc.src.stdlib.calloc
+    libc.src.stdlib.realloc
+    libc.src.stdlib.free
+
+
+  )
+endif()
+
 set(TARGET_LLVMLIBC_ENTRYPOINTS
   ${TARGET_LIBC_ENTRYPOINTS}
   ${TARGET_LIBM_ENTRYPOINTS}

libc/lib/CMakeLists.txt

@@ -1,27 +1,7 @@
-set(SCUDO_DEPS "")
-
-if(LLVM_LIBC_INCLUDE_SCUDO)
-  include(../../compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake)
-  if(NOT (LIBC_TARGET_ARCHITECTURE IN_LIST ALL_SCUDO_STANDALONE_SUPPORTED_ARCH))
-    message(FATAL_ERROR "Architecture ${LIBC_TARGET_ARCHITECTURE} is not supported by SCUDO. 
-Either disable LLVM_LIBC_INCLUDE_SCUDO or change your target architecture.")
-  endif()
-  list(APPEND SCUDO_DEPS RTScudoStandalone.${LIBC_TARGET_ARCHITECTURE} RTScudoStandaloneCWrappers.${LIBC_TARGET_ARCHITECTURE})
-  if((LIBC_TARGET_ARCHITECTURE IN_LIST ALL_GWP_ASAN_SUPPORTED_ARCH) AND COMPILER_RT_BUILD_GWP_ASAN)
-    list(APPEND SCUDO_DEPS RTGwpAsan.${LIBC_TARGET_ARCHITECTURE} 
-                            RTGwpAsanBacktraceLibc.${LIBC_TARGET_ARCHITECTURE} 
-                            RTGwpAsanSegvHandler.${LIBC_TARGET_ARCHITECTURE})
-  elseif(COMPILER_RT_BUILD_GWP_ASAN)
-    message(WARNING "Architecture ${LIBC_TARGET_ARCHITECTURE} is not supported by GWP-ASan. Skipping.")
-  endif()
-endif()
-
 add_entrypoint_library(
   llvmlibc
   DEPENDS
   ${TARGET_LLVMLIBC_ENTRYPOINTS}
-  EXT_DEPS
-  ${SCUDO_DEPS}
 )
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)

libc/spec/stdc.td

@@ -513,6 +513,11 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"strtoul", RetValSpec<UnsignedLongType>, [ArgSpec<ConstCharRestrictedPtr>, ArgSpec<CharRestrictedPtrPtr>, ArgSpec<IntType>]>,
           FunctionSpec<"strtoull", RetValSpec<UnsignedLongLongType>, [ArgSpec<ConstCharRestrictedPtr>, ArgSpec<CharRestrictedPtrPtr>, ArgSpec<IntType>]>,
 
+          FunctionSpec<"malloc", RetValSpec<VoidPtr>, [ArgSpec<SizeTType>]>,
+          FunctionSpec<"calloc", RetValSpec<VoidPtr>, [ArgSpec<SizeTType>, ArgSpec<SizeTType>]>,
+          FunctionSpec<"realloc", RetValSpec<VoidPtr>, [ArgSpec<VoidPtr>, ArgSpec<SizeTType>]>,
+          FunctionSpec<"free", RetValSpec<VoidType>, [ArgSpec<VoidPtr>]>,
+
           FunctionSpec<"_Exit", RetValSpec<NoReturn>, [ArgSpec<IntType>]>,
       ]
   >;

libc/src/stdlib/CMakeLists.txt

@@ -181,6 +181,48 @@ add_entrypoint_object(
     libc.include.stdlib
 )
 
+if(LLVM_LIBC_INCLUDE_SCUDO)
+  set(SCUDO_DEPS "")
+
+  include(${LIBC_SOURCE_DIR}/../compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake)
+  if(NOT (LIBC_TARGET_ARCHITECTURE IN_LIST ALL_SCUDO_STANDALONE_SUPPORTED_ARCH))
+    message(FATAL_ERROR "Architecture ${LIBC_TARGET_ARCHITECTURE} is not supported by SCUDO. 
+      Either disable LLVM_LIBC_INCLUDE_SCUDO or change your target architecture.")
+  endif()
+  list(APPEND SCUDO_DEPS RTScudoStandalone.${LIBC_TARGET_ARCHITECTURE} 
+       RTScudoStandaloneCWrappers.${LIBC_TARGET_ARCHITECTURE})
+  if((LIBC_TARGET_ARCHITECTURE IN_LIST ALL_GWP_ASAN_SUPPORTED_ARCH) 
+      AND COMPILER_RT_BUILD_GWP_ASAN)
+    list(APPEND SCUDO_DEPS RTGwpAsan.${LIBC_TARGET_ARCHITECTURE} 
+                            RTGwpAsanBacktraceLibc.${LIBC_TARGET_ARCHITECTURE} 
+                            RTGwpAsanSegvHandler.${LIBC_TARGET_ARCHITECTURE})
+  elseif(COMPILER_RT_BUILD_GWP_ASAN)
+    message(WARNING "Architecture ${LIBC_TARGET_ARCHITECTURE} is not supported by GWP-ASan. Skipping.")
+  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(
+    free
+    DEPENDS
+      ${SCUDO_DEPS}
+  )
+
+endif()
+
 if(NOT LLVM_LIBC_FULL_BUILD)
   return()
 endif()