| Message ID | 20181126230450.672-1-richard.henderson@linaro.org |
|---|---|
| Headers | show |
| Series | tcg: Remove unreachable code | expand |
Hi,
This series seems to have some coding style problems. See output below for
more information:
Message-id: 20181126230450.672-1-richard.henderson@linaro.org
Subject: [Qemu-devel] [PATCH 0/4] tcg: Remove unreachable code
Type: series
=== TEST SCRIPT BEGIN ===
#!/bin/bash
BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
failed=1
echo
fi
n=$((n+1))
done
exit $failed
=== TEST SCRIPT END ===
Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
* [new tag] patchew/20181128.181700.1038782556965887223.atsushi.nemoto@sord.co.jp -> patchew/20181128.181700.1038782556965887223.atsushi.nemoto@sord.co.jp
Switched to a new branch 'test'
f76b3bd tcg: Add reachable_code_pass
81bb184 tcg: Reference count labels
5599b43 tcg: Add TCG_CALL_NO_RETURN
d27ec83 tcg: Renumber TCG_CALL_* flags
=== OUTPUT BEGIN ===
Checking PATCH 1/4: tcg: Renumber TCG_CALL_* flags...
Checking PATCH 2/4: tcg: Add TCG_CALL_NO_RETURN...
Checking PATCH 3/4: tcg: Reference count labels...
ERROR: spaces prohibited around that ':' (ctx:WxW)
#83: FILE: tcg/tcg.h:249:
+ unsigned id : 15;
^
ERROR: spaces prohibited around that ':' (ctx:WxW)
#84: FILE: tcg/tcg.h:250:
+ unsigned refs : 16;
^
total: 2 errors, 0 warnings, 56 lines checked
Your patch has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
Checking PATCH 4/4: tcg: Add reachable_code_pass...
=== OUTPUT END ===
Test command exited with code: 1
---
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I've been meaning to add a trivial cleanup pass like this for some time. There have occasionally been instaces within front ends wherein we want to raise an invalid operand exception (or some such) deep within a set of subroutines. And without a longjmp (or some such) back to the top level of the translator loop we must return a dummy value so that we produce valid tcg code following the exception. While we still probably have to return a dummy value, we can clean up the dead code that follows the exception. In addition, when optimization is able to fold a conditional branch, the original code sequence: brcond x,y,$L1 goto_tb mov pc,foo exit_tb $1 set_label $L1 goto_tb mov pc,bar exit_tb $2 The initial brcond is either folded to br, or removed as a never taken branch, which leaves one of the two sets of goto_tb ... exit_tb unreachable. With this we can completely remove the code for the dead branch. While I do not expect this to have any noticable effect, this dead code could get in the way of some other changes that I'm planning. r~ Richard Henderson (4): tcg: Renumber TCG_CALL_* flags tcg: Add TCG_CALL_NO_RETURN tcg: Reference count labels tcg: Add reachable_code_pass include/exec/helper-head.h | 13 ++++++ include/exec/helper-tcg.h | 21 ++++++--- tcg/tcg-op.h | 1 + tcg/tcg.h | 11 +++-- tcg/tcg-op.c | 2 + tcg/tcg.c | 96 ++++++++++++++++++++++++++++++++++++++ 6 files changed, 133 insertions(+), 11 deletions(-) -- 2.17.2