d97dd988ec
The following thread was helpful while writing this script:
https://github.com/coccinelle/coccinelle/issues/86
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20170718045540.16322-3-f4bug@amsat.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
108 lines
2.9 KiB
Plaintext
108 lines
2.9 KiB
Plaintext
// optimize TCG using extract op
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//
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// Copyright: (C) 2017 Philippe Mathieu-Daudé. GPLv2+.
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// Confidence: High
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// Options: --macro-file scripts/cocci-macro-file.h
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//
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// Nikunj A Dadhania optimization:
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// http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg05211.html
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// Aurelien Jarno optimization:
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// http://lists.nongnu.org/archive/html/qemu-devel/2017-05/msg01466.html
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//
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// This script can be run either using spatch locally or via a docker image:
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//
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// $ spatch \
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// --macro-file scripts/cocci-macro-file.h \
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// --sp-file scripts/coccinelle/tcg_gen_extract.cocci \
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// --keep-comments --in-place \
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// --use-gitgrep --dir target
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//
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// $ docker run --rm -v `pwd`:`pwd` -w `pwd` philmd/coccinelle \
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// --macro-file scripts/cocci-macro-file.h \
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// --sp-file scripts/coccinelle/tcg_gen_extract.cocci \
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// --keep-comments --in-place \
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// --use-gitgrep --dir target
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@initialize:python@
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@@
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import sys
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fd = sys.stderr
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def debug(msg="", trailer="\n"):
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fd.write("[DBG] " + msg + trailer)
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def low_bits_count(value):
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bits_count = 0
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while (value & (1 << bits_count)):
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bits_count += 1
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return bits_count
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def Mn(order): # Mersenne number
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return (1 << order) - 1
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@match@
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identifier ret;
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metavariable arg;
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constant ofs, msk;
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position shr_p, and_p;
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@@
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(
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tcg_gen_shri_i32@shr_p
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tcg_gen_shri_i64@shr_p
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tcg_gen_shri_tl@shr_p
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)(ret, arg, ofs);
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... WHEN != ret
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(
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tcg_gen_andi_i32@and_p
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tcg_gen_andi_i64@and_p
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tcg_gen_andi_tl@and_p
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)(ret, ret, msk);
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@script:python verify_len depends on match@
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ret_s << match.ret;
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msk_s << match.msk;
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shr_p << match.shr_p;
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extract_len;
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@@
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is_optimizable = False
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debug("candidate at %s:%s" % (shr_p[0].file, shr_p[0].line))
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try: # only eval integer, no #define like 'SR_M' (cpp did this, else some headers are missing).
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msk_v = long(msk_s.strip("UL"), 0)
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msk_b = low_bits_count(msk_v)
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if msk_b == 0:
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debug(" value: 0x%x low_bits: %d" % (msk_v, msk_b))
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else:
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debug(" value: 0x%x low_bits: %d [Mersenne number: 0x%x]" % (msk_v, msk_b, Mn(msk_b)))
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is_optimizable = Mn(msk_b) == msk_v # check low_bits
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coccinelle.extract_len = "%d" % msk_b
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debug(" candidate %s optimizable" % ("IS" if is_optimizable else "is NOT"))
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except:
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debug(" ERROR (check included headers?)")
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cocci.include_match(is_optimizable)
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debug()
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@replacement depends on verify_len@
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identifier match.ret;
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metavariable match.arg;
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constant match.ofs, match.msk;
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position match.shr_p, match.and_p;
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identifier verify_len.extract_len;
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@@
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(
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-tcg_gen_shri_i32@shr_p(ret, arg, ofs);
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+tcg_gen_extract_i32(ret, arg, ofs, extract_len);
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... WHEN != ret
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-tcg_gen_andi_i32@and_p(ret, ret, msk);
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-tcg_gen_shri_i64@shr_p(ret, arg, ofs);
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+tcg_gen_extract_i64(ret, arg, ofs, extract_len);
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... WHEN != ret
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-tcg_gen_andi_i64@and_p(ret, ret, msk);
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-tcg_gen_shri_tl@shr_p(ret, arg, ofs);
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+tcg_gen_extract_tl(ret, arg, ofs, extract_len);
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... WHEN != ret
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-tcg_gen_andi_tl@and_p(ret, ret, msk);
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)
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