[libc][wctype] Add cmake flag for configuring wctype implementation used

[mleleszi]

#170525

Based on our RFC, we are starting the implementation of the wctype header with C.UTF8 support. This implementation will increase the binary size by approximately ~70KB, so this PR introduces a flag so that this is configurable, allowing the user to choose between a simple ASCII implementation or the full Unicode one.

[llvmbot]

@llvm/pr-subscribers-libc

Author: Marcell Leleszi (mleleszi)

Changes

#170525

Based on our RFC, we are starting the implementation of the wctype header with C.UTF8 support. This implementation will increase the binary size by approximately ~70KB, so this PR introduces a flag so that this is configurable, allowing the user to choose between a simple ASCII implementation or the full Unicode one.

---

Full diff: https://github.com/llvm/llvm-project/pull/170531.diff

1 Files Affected:

• (modified) libc/config/config.json (+6)

diff --git a/libc/config/config.json b/libc/config/config.json
index cfbe9a43948ea..a7844e4fe2dd1 100644
--- a/libc/config/config.json
+++ b/libc/config/config.json
@@ -130,5 +130,11 @@
       "value": true,
       "doc": "Add nullptr checks in the library's implementations to some functions for which passing nullptr is undefined behavior."
     }
+  },
+  "wctype": {
+    "LIBC_CONF_WCTYPE_MODE": {
+      "value": "LIBC_WCTYPE_MODE_ASCII",
+      "doc": "The implementation used for wctype, acceptable values are LIBC_WCTYPE_MODE_ASCII and LIBC_WCTYPE_MODE_UTF8."
+    }
   }
 }

[bassiounix]

We need to add some description to let people know how to utilize this option with its possible values.
Please add some description in the docs like:

• llvm-project/libc/docs/configure.rst

  Line 22 in 035f811

  $> cmake <other build options> -DLIBC_CONF_PRINTF_DISABLE_FLOAT=ON <more options>

• llvm-project/libc/docs/configure.rst

  Line 40 in 035f811

  - ``LIBC_CONF_PRINTF_DISABLE_FLOAT``: Disable printing floating point values in printf and friends.

[michaelrj-google]

The config flag looks good, if you run the cmake it should automatically update the documentation.

[bassiounix]

The config flag looks good, if you run the cmake it should automatically update the documentation.

I had no idea it's automatically generated. I thought we write the docs ourselves.

[michaelrj-google]

The configuration documentation and the lists of implemented functions are both automatically generated: https://github.com/llvm/llvm-project/blob/main/libc/utils/docgen/docgen.py

[mleleszi]

Done, regenerated docs

[bassiounix]

LGTM