modernize-pass-by-value.sh

#!/bin/bash -e
# \author Hans J. Johnson
#
# This script assists with using clang-tidy.
#
# STEP 0;
# I recommend downloading or building the latest
# version of llvm with clang and the clang-tidy
# tools in a private repo. NOTE:  Apple does
# not currently distribute these.
#
# STEP 1:
# Build your source tree with cmake and use
# export PATH=${MYCLANG_FROM_STEP0}:$PATH
# export CXX=${MYCLANG_FROM_STEP0}
# export CC=${MYCLANG_FROM_STEP0}
# cd ${MYBLD}
# cmake -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON ${MYSRC}
# to generate the compile_commands.json
# comple options database files.
#
# STEP 2:
# Run clang-tidy with the

SRCDIR=$1
BLDDIR=$2

this_script_name=$(basename $0)
CMTMSG=$(mktemp -q /tmp/${this_script_name}.XXXXXX)
FILES_TO_CHECK=$(mktemp -q /tmp/${this_script_name}_files.XXXXXX)

cat > ${CMTMSG} << EOF
PERF: Allow compiler to choose best way to construct a copy

With move semantics added to the language and the standard library updated with
move constructors added for many types it is now interesting to take an
argument directly by value, instead of by const-reference, and then copy. This
check allows the compiler to take care of choosing the best way to construct
the copy.

The transformation is usually beneficial when the calling code passes an rvalue
and assumes the move construction is a cheap operation. This short example
illustrates how the construction of the value happens:


SRCDIR=${SRCDIR} #My local SRC
BLDDIR=${BLDDIR} #My local BLD

cd ${BLDDIR}
run-clang-tidy.py -extra-arg=-D__clang__ -checks=-*,modernize-pass-by-value  -header-filter=.* -fix

EOF

export CC=/Users/johnsonhj/local/ccache/bin/clang_ccache
export CXX=/Users/johnsonhj/local/ccache/bin/clang++11_ccache
export PATH=~/local/llvm/llvm_trunk-build/bin:$PATH
cd ${BLDDIR}
/Users/johnsonhj/Dashboard/src/scripts/run-clang-tidy.py -extra-arg=-D__clang__ -checks=-*,modernize-pass-by-value  -header-filter=.* -fix

cd ${SRCDIR}
git add -A && git commit --file ${CMTMSG}