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Diffstat (limited to 'scripts/gen-py-const.awk')
| -rw-r--r-- | scripts/gen-py-const.awk | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/scripts/gen-py-const.awk b/scripts/gen-py-const.awk new file mode 100644 index 0000000..4586f59 --- /dev/null +++ b/scripts/gen-py-const.awk @@ -0,0 +1,118 @@ +# Script to generate constants for Python pretty printers. +# +# Copyright (C) 2016 Free Software Foundation, Inc. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# <http://www.gnu.org/licenses/>. + +# This script is a smaller version of the clever gen-asm-const.awk hack used to +# generate ASM constants from .sym files. We'll use this to generate constants +# for Python pretty printers. +# +# The input to this script are .pysym files that look like: +# #C_Preprocessor_Directive... +# NAME1 +# NAME2 expression... +# +# A line giving just a name implies an expression consisting of just that name. +# Comments start with '--'. +# +# The output of this script is a 'dummy' function containing 'asm' declarations +# for each non-preprocessor line in the .pysym file. The expression values +# will appear as input operands to the 'asm' declaration. For example, if we +# have: +# +# /* header.h */ +# #define MACRO 42 +# +# struct S { +# char c1; +# char c2; +# char c3; +# }; +# +# enum E { +# ZERO, +# ONE +# }; +# +# /* symbols.pysym */ +# #include <stddef.h> +# #include "header.h" +# -- This is a comment +# MACRO +# C3_OFFSET offsetof(struct S, c3) +# E_ONE ONE +# +# the output will be: +# +# #include <stddef.h> +# #include "header.h" +# void dummy(void) +# { +# asm ("@name@MACRO@value@%0@" : : "i" (MACRO)); +# asm ("@name@C3_OFFSET@value@%0@" : : "i" (offsetof(struct S, c3))); +# asm ("@name@E_ONE@value@%0@" : : "i" (ONE)); +# } +# +# We'll later feed this output to gcc -S. Since '-S' tells gcc to compile but +# not assemble, gcc will output something like: +# +# dummy: +# ... +# @name@MACRO@value@$42@ +# @name@C3_OFFSET@value@$2@ +# @name@E_ONE@value@$1@ +# +# Finally, we can process that output to extract the constant values. +# Notice gcc may prepend a special character such as '$' to each value. + +# found_symbol indicates whether we found a non-comment, non-preprocessor line. +BEGIN { found_symbol = 0 } + +# C preprocessor directives go straight through. +/^#/ { print; next; } + +# Skip comments. +/--/ { next; } + +# Trim leading whitespace. +{ sub(/^[[:blank:]]*/, ""); } + +# If we found a non-comment, non-preprocessor line, print the 'dummy' function +# header. +NF > 0 && !found_symbol { + print "void dummy(void)\n{"; + found_symbol = 1; +} + +# If the line contains just a name, duplicate it so we can use that name +# as the value of the expression. +NF == 1 { sub(/^.*$/, "& &"); } + +# If a line contains a name and an expression... +NF > 1 { + name = $1; + + # Remove any characters before the second field. + sub(/^[^[:blank:]]+[[:blank:]]+/, ""); + + # '$0' ends up being everything that appeared after the first field + # separator. + printf " asm (\"@name@%s@value@%0@\" : : \"i\" (%s));\n", name, $0; +} + +# Close the 'dummy' function. +END { if (found_symbol) print "}"; } |