[libc] Add support for more file functions

[jhuber6]

Summary

This patch adds support for more trivial file functions. This leaves out
specifically fgets. This is because as implemented this does not have
the correct behavior as it does not stop on EOF or newline since we map
it all to fread. This will probably need to be fixed somehow.

[jdoerfert]

This is because as implemented this does not have the correct behavior as it does not stop on EOF or newline since we map it all to fread.

Because the RPC maps it to fread or because the libc default impl does?

[jhuber6]

In D156480#4540552, @jdoerfert wrote:

This is because as implemented this does not have the correct behavior as it does not stop on EOF or newline since we map it all to fread.

Because the RPC maps it to fread or because the libc default impl does?

Haven't tested w/ the CPU version of libc their version maps to a linux syscall which has similar semantics I think.

[jhuber6]

ping

[tianshilei1992]

libc/docs/gpu/support.rst

132

This two don't need RPC?

[jhuber6]

libc/docs/gpu/support.rst

132

So that's actually a can of worms I'm not sure what the best way to handle is. These don't require RPC because the file class maintains some internal state about the result of the last action, e.g. if the last return value was negative. But, this means that calling feof on the GPU will return something different if the last call was on the CPU. However, it also means that if we didn't want that to happen we'd need everything to go through RPC with very little ability to optimize anything from the GPU side. I'm sort-of leaning towards treating this as a similar case if you were to statically link a MUSL application with a glibc one, you should kind of see them as separate and not expect them to work well when mixed.

libc/config/gpu/entrypoints.txt

set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.realloc
     libc.src.stdlib.free
 
     # errno.h entrypoints
     libc.src.errno.errno
 
     # stdio.h entrypoints
     libc.src.stdio.puts
+    libc.src.stdio.putc
+    libc.src.stdio.putchar
     libc.src.stdio.fputs
     libc.src.stdio.fread
+    libc.src.stdio.feof
+    libc.src.stdio.ferror
+    libc.src.stdio.fgetc
+    libc.src.stdio.fputc
     libc.src.stdio.fclose
     libc.src.stdio.fopen
+    libc.src.stdio.fwrite
+    libc.src.stdio.getchar
+    libc.src.stdio.getc
     libc.src.stdio.stdin
     libc.src.stdio.stdout
     libc.src.stdio.stderr
 
     # inttypes.h entrypoints
     libc.src.inttypes.imaxabs
     libc.src.inttypes.imaxdiv
     libc.src.inttypes.strtoimax

libc/docs/gpu/support.rst

 
 =============  =========  ============
 Function Name  Available  RPC Required
 =============  =========  ============
 puts           |check|    |check|
 fputs          |check|    |check|
 fclose         |check|    |check|
 fopen          |check|    |check|
+putc           |check|    |check|
+putchar        |check|    |check|
+feof           |check|
+ferror         |check|
+fgetc          |check|    |check|
+fputc          |check|    |check|
+fwrite         |check|    |check|
+getchar        |check|    |check|
+getc           |check|    |check|
 =============  =========  ============

libc/test/src/stdio/CMakeLists.txt

SRCS
     fopen_test.cpp
   DEPENDS
     libc.src.stdio.fread
     libc.src.stdio.fputs
     libc.src.stdio.fclose
     libc.src.stdio.fopen
 )
 
-add_libc_unittest(
+add_libc_test(
   putc_test
   SUITE
     libc_stdio_unittests
   SRCS
     putc_test.cpp
   DEPENDS
     libc.src.stdio.putc
     libc.src.stdio.fclose
DEPENDS
       libc.src.fcntl.open
       libc.src.stdio.remove
       libc.src.sys.stat.mkdirat
       libc.src.unistd.access
       libc.src.unistd.close
   )
 endif()
 
-add_libc_unittest(
+add_libc_test(
   fgetc_test
   SUITE
     libc_stdio_unittests
   SRCS
     fgetc_test.cpp
   DEPENDS
     libc.include.stdio
     libc.src.errno.errno