diff options
Diffstat (limited to 'libc/kernel/tools/clean_header.py')
| -rwxr-xr-x | libc/kernel/tools/clean_header.py | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/libc/kernel/tools/clean_header.py b/libc/kernel/tools/clean_header.py index 238087bbc..660181772 100755 --- a/libc/kernel/tools/clean_header.py +++ b/libc/kernel/tools/clean_header.py @@ -1,5 +1,78 @@ #!/usr/bin/env python + +#------------------------------------------------------------------------------ +# Description of the header clean process +#------------------------------------------------------------------------------ +# Here is the list of actions performed by this script to clean the original +# kernel headers. +# +# 1. Optimize well-known macros (e.g. __KERNEL__, __KERNEL_STRICT_NAMES) +# +# This pass gets rid of everything that is guarded by a well-known macro +# definition. This means that a block like: +# +# #ifdef __KERNEL__ +# .... +# #endif +# +# Will be totally omitted from the output. The optimizer is smart enough to +# handle all complex C-preprocessor conditional expression appropriately. +# This means that, for example: +# +# #if defined(__KERNEL__) || defined(FOO) +# ... +# #endif +# +# Will be transformed into: +# +# #ifdef FOO +# ... +# #endif +# +# See tools/defaults.py for the list of well-known macros used in this pass, +# in case you need to update it in the future. +# +# Note that this also removes any reference to a kernel-specific +# configuration macro like CONFIG_FOO from the clean headers. +# +# +# 2. Remove variable and function declarations: +# +# This pass scans non-directive text and only keeps things that look like a +# typedef/struct/union/enum declaration. This allows us to get rid of any +# variables or function declarations that should only be used within the +# kernel anyway (and which normally *should* be guarded by an #ifdef +# __KERNEL__ ... #endif block, if the kernel writers were not so messy). +# +# There are, however, a few exceptions: it is seldom useful to keep the +# definition of some static inline functions performing very simple +# operations. A good example is the optimized 32-bit byte-swap function +# found in: +# +# arch-arm/asm/byteorder.h +# +# The list of exceptions is in tools/defaults.py in case you need to update +# it in the future. +# +# Note that we do *not* remove macro definitions, including these macro that +# perform a call to one of these kernel-header functions, or even define other +# functions. We consider it safe since userland applications have no business +# using them anyway. +# +# +# 3. Whitespace cleanup: +# +# The final pass removes any comments and empty lines from the final headers. +# +# +# 4. Add a standard disclaimer: +# +# The message: +# +# /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */ # +# Is prepended to each generated header. +#------------------------------------------------------------------------------ import sys, cpp, kernel, glob, os, re, getopt from defaults import * |