view auto/cc/name @ 6627:ad736705a744

HTTP/2: avoid left-shifting signed integer into the sign bit. On non-aligned platforms, properly cast argument before left-shifting it in ngx_http_v2_parse_uint32 that is used with u_char. Otherwise it propagates to int to hold the value and can step over the sign bit. Usually, on known compilers, this results in negation. Furthermore, a subsequent store into a wider type, that is ngx_uint_t on 64-bit platforms, results in sign-extension. In practice, this can be observed in debug log as a very large exclusive bit value, when client sent PRIORITY frame with exclusive bit set: : *14 http2 PRIORITY frame sid:5 on 1 excl:8589934591 weight:17 Found with UndefinedBehaviorSanitizer.
author Sergey Kandaurov <pluknet@nginx.com>
date Thu, 07 Jul 2016 21:03:21 +0300
parents 78f8ac479735
children 325b3042edd6
line wrap: on
line source


# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


if [ "$NGX_PLATFORM" != win32 ]; then

    ngx_feature="C compiler"
    ngx_feature_name=
    ngx_feature_run=yes
    ngx_feature_incs=
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test=
    . auto/feature

    if [ $ngx_found = no ]; then
        echo
        echo $0: error: C compiler $CC is not found
        echo
        exit 1
    fi

fi


if [ "$CC" = cl ]; then
    NGX_CC_NAME=msvc
    echo " + using Microsoft Visual C++ compiler"

elif [ "$CC" = wcl386 ]; then
    NGX_CC_NAME=owc
    echo " + using Open Watcom C compiler"

elif [ "$CC" = bcc32 ]; then
    NGX_CC_NAME=bcc
    echo " + using Borland C++ compiler"

elif `$CC -V 2>&1 | grep '^Intel(R) C' >/dev/null 2>&1`; then
    NGX_CC_NAME=icc
    echo " + using Intel C++ compiler"

elif `$CC -v 2>&1 | grep 'gcc version' >/dev/null 2>&1`; then
    NGX_CC_NAME=gcc
    echo " + using GNU C compiler"

elif `$CC -v 2>&1 | grep '\(clang\|LLVM\) version' >/dev/null 2>&1`; then
    NGX_CC_NAME=clang
    echo " + using Clang C compiler"

elif `$CC -V 2>&1 | grep 'Sun C' >/dev/null 2>&1`; then
    NGX_CC_NAME=sunc
    echo " + using Sun C compiler"

elif `$CC -V 2>&1 | grep '^Compaq C' >/dev/null 2>&1`; then
    NGX_CC_NAME=ccc
    echo " + using Compaq C compiler"

elif `$CC -V 2>&1 | grep '^aCC: ' >/dev/null 2>&1`; then
    NGX_CC_NAME=acc
    echo " + using HP aC++ compiler"

else
    NGX_CC_NAME=unknown

fi