[libc][Fix] Move generic stdio implementations to a new directory

[jhuber6]

Summary

For whatever reason, the CMake did not like having the generic_
version live in the same directory. This patch pushes them to a new
directory, which is probably clearer anyway.

[michaelrj]

LGTM with nit

libc/src/stdio/CMakeLists.txt

25

shouldn't this be in an else with the above condition?

[jhuber6]

libc/src/stdio/CMakeLists.txt

25

We already have a linux/ special-case which cause this to not be built. I believe this is the same approach we do for the math since even though we make the target, if there's no top level dependency on it we won't actually use it.

[jhuber6]

Make the GPU early exit in the generic version. This is the same approach that the math uses but we don't make all the entrypoints in this case so just special case exit for the GPU.

[sivachandra]

libc/src/stdio/CMakeLists.txt

25

I suggested elseif instead of else because we want to ignore (may be with a VERBOSE message) if neither an OS-specific implementation nor a generic implementation is available. This is useful in the case when a particular entrypoint is not enabled in entrypoints.txt. In such a case, the real entrypoint will be skipped and hence the ALIAS should also be skipped. The right fix is likely here: https://github.com/llvm/llvm-project/blob/main/libc/cmake/modules/LLVMLibCObjectRules.cmake#L309. But, that is beyond the scope of this change.

libc/src/stdio/CMakeLists.txt

 # Helper function that creates an alias if a target specific implementation
 # exists, otherwise it uses a generic one.
 function(add_stdio_entrypoint_object name)
   if(TARGET libc.src.stdio.${LIBC_TARGET_OS}.${name})
     add_entrypoint_object(
       ${name}
       ALIAS
       DEPENDS
         .${LIBC_TARGET_OS}.${name}
     )
-  elseif(TARGET libc.src.stdio.generic_${name})
+  elseif(TARGET libc.src.stdio.generic.${name})
     add_entrypoint_object(
       ${name}
       ALIAS
       DEPENDS
-        .generic_${name}
+        .generic.${name}
     )
   endif()
 endfunction(add_stdio_entrypoint_object)
 
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/generic)
 if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
 endif()
 
 add_subdirectory(printf_core)
 add_subdirectory(scanf_core)
 
 add_entrypoint_object(
   fopen
   SRCS
     fopen.cpp
   HDRS
add_entrypoint_object(
   DEPENDS
     libc.src.errno.errno
     libc.include.stdio
     libc.src.__support.File.file
     libc.src.__support.File.platform_file
 )
 
 add_entrypoint_object(
-  generic_fputs
-  SRCS
-    fputs.cpp
-  HDRS
-    fputs.h
-  DEPENDS
-    libc.src.errno.errno
-    libc.include.stdio
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-
-add_entrypoint_object(
-  generic_puts
-  SRCS
-    puts.cpp
-  HDRS
-    puts.h
-  DEPENDS
-    libc.src.errno.errno
-    libc.include.stdio
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-add_entrypoint_object(
   fseek
   SRCS
     fseek.cpp
   HDRS
     fseek.h
   DEPENDS
     libc.src.errno.errno
     libc.include.stdio
HDRS
     fopencookie.h
   DEPENDS
     libc.include.stdio
     libc.src.__support.CPP.new
     libc.src.__support.File.file
 )
 
 add_entrypoint_object(
-  generic_stdin
-  SRCS
-    stdin.cpp
-  HDRS
-    stdin.h
-  DEPENDS
-    libc.include.stdio
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-add_entrypoint_object(
-  generic_stdout
-  SRCS
-    stdout.cpp
-  HDRS
-    stdout.h
-  DEPENDS
-    libc.include.stdio
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-add_entrypoint_object(
-  generic_stderr
-  SRCS
-    stderr.cpp
-  HDRS
-    stderr.h
-  DEPENDS
-    libc.include.stdio
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-add_entrypoint_object(
   setbuf
   SRCS
     setbuf.cpp
   HDRS
     setbuf.h
   DEPENDS
     libc.src.errno.errno
     libc.include.stdio

libc/src/stdio/generic/CMakeLists.txt

+if(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  # The GPU build cannot use any generic implementations.
+  return()
+endif()
+
+add_entrypoint_object(
+  fputs
+  SRCS
+    fputs.cpp
+  HDRS
+    ../fputs.h
+  DEPENDS
+    libc.src.errno.errno
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  puts
+  SRCS
+    puts.cpp
+  HDRS
+    ../puts.h
+  DEPENDS
+    libc.src.errno.errno
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  stdin
+  SRCS
+    stdin.cpp
+  HDRS
+    ../stdin.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  stdout
+  SRCS
+    stdout.cpp
+  HDRS
+    ../stdout.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_entrypoint_object(
+  stderr
+  SRCS
+    stderr.cpp
+  HDRS
+    ../stderr.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)