musl/configure

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#!/bin/sh
usage () {
cat <<EOF
Usage: $0 [OPTION]... [VAR=VALUE]... [TARGET]
To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE. See below for descriptions of some of the useful variables.
Defaults for the options are specified in brackets.
Installation directories:
--prefix=PREFIX main installation prefix [/usr/local/musl]
--exec-prefix=EPREFIX installation prefix for executable files [PREFIX]
Fine tuning of the installation directories:
--bindir=DIR user executables [EPREFIX/bin]
--libdir=DIR library files for the linker [PREFIX/lib]
--includedir=DIR include files for the C compiler [PREFIX/include]
--syslibdir=DIR location for the dynamic linker [/lib]
System types:
--target=TARGET configure to run on target TARGET [detected]
--host=HOST same as --target
Optional features:
--enable-optimize=... optimize listed components for speed over size [auto]
--enable-debug build with debugging information [disabled]
--enable-warnings build with recommended warnings flags [disabled]
--enable-visibility use global visibility options to optimize PIC [auto]
--enable-wrapper=... build given musl toolchain wrapper [auto]
--disable-shared inhibit building shared library [enabled]
--disable-static inhibit building static library [enabled]
Some influential environment variables:
CC C compiler command [detected]
CFLAGS C compiler flags [-Os -pipe ...]
CROSS_COMPILE prefix for cross compiler and tools [none]
LIBCC compiler runtime library [detected]
Use these variables to override the choices made by configure.
EOF
exit 0
}
# Helper functions
quote () {
tr '\n' ' ' <<EOF | grep '^[-[:alnum:]_=,./:]* $' >/dev/null 2>&1 && { echo "$1" ; return 0 ; }
$1
EOF
printf %s\\n "$1" | sed -e "s/'/'\\\\''/g" -e "1s/^/'/" -e "\$s/\$/'/" -e "s#^'\([-[:alnum:]_,./:]*\)=\(.*\)\$#\1='\2#"
}
echo () { printf "%s\n" "$*" ; }
fail () { echo "$*" ; exit 1 ; }
fnmatch () { eval "case \"\$2\" in $1) return 0 ;; *) return 1 ;; esac" ; }
cmdexists () { type "$1" >/dev/null 2>&1 ; }
trycc () { test -z "$CC" && cmdexists "$1" && CC=$1 ; }
stripdir () {
while eval "fnmatch '*/' \"\${$1}\"" ; do eval "$1=\${$1%/}" ; done
}
trycppif () {
printf "checking preprocessor condition %s... " "$1"
echo "typedef int x;" > "$tmpc"
echo "#if $1" >> "$tmpc"
echo "#error yes" >> "$tmpc"
echo "#endif" >> "$tmpc"
if $CC $2 -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "false\n"
return 1
else
printf "true\n"
return 0
fi
}
tryflag () {
printf "checking whether compiler accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
if $CC $CFLAGS_TRY $2 -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
return 0
else
printf "no\n"
return 1
fi
}
tryldflag () {
printf "checking whether linker accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
if $CC $LDFLAGS_TRY -nostdlib -shared "$2" -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
return 0
else
printf "no\n"
return 1
fi
}
# Beginning of actual script
CFLAGS_C99FSE=
CFLAGS_AUTO=
CFLAGS_MEMOPS=
CFLAGS_NOSSP=
CFLAGS_TRY=
LDFLAGS_AUTO=
LDFLAGS_TRY=
OPTIMIZE_GLOBS=
prefix=/usr/local/musl
exec_prefix='$(prefix)'
bindir='$(exec_prefix)/bin'
libdir='$(prefix)/lib'
includedir='$(prefix)/include'
syslibdir='/lib'
tools=
tool_libs=
target=
optimize=auto
debug=no
warnings=no
visibility=auto
shared=auto
static=yes
wrapper=auto
gcc_wrapper=no
clang_wrapper=no
for arg ; do
case "$arg" in
--help) usage ;;
--prefix=*) prefix=${arg#*=} ;;
--exec-prefix=*) exec_prefix=${arg#*=} ;;
--bindir=*) bindir=${arg#*=} ;;
--libdir=*) libdir=${arg#*=} ;;
--includedir=*) includedir=${arg#*=} ;;
--syslibdir=*) syslibdir=${arg#*=} ;;
--enable-shared|--enable-shared=yes) shared=yes ;;
--disable-shared|--enable-shared=no) shared=no ;;
--enable-static|--enable-static=yes) static=yes ;;
--disable-static|--enable-static=no) static=no ;;
--enable-optimize) optimize=yes ;;
--enable-optimize=*) optimize=${arg#*=} ;;
--disable-optimize) optimize=no ;;
--enable-debug|--enable-debug=yes) debug=yes ;;
--disable-debug|--enable-debug=no) debug=no ;;
--enable-warnings|--enable-warnings=yes) warnings=yes ;;
--disable-warnings|--enable-warnings=no) warnings=no ;;
--enable-visibility|--enable-visibility=yes) visibility=yes ;;
--disable-visibility|--enable-visibility=no) visibility=no ;;
--enable-wrapper|--enable-wrapper=yes) wrapper=detect ;;
--enable-wrapper=all) wrapper=yes ; gcc_wrapper=yes ; clang_wrapper=yes ;;
--enable-wrapper=gcc) wrapper=yes ; gcc_wrapper=yes ;;
--enable-wrapper=clang) wrapper=yes ; clang_wrapper=yes ;;
--disable-wrapper|--enable-wrapper=no) wrapper=no ;;
--enable-gcc-wrapper|--enable-gcc-wrapper=yes) wrapper=yes ; gcc_wrapper=yes ;;
--disable-gcc-wrapper|--enable-gcc-wrapper=no) wrapper=no ;;
--enable-*|--disable-*|--with-*|--without-*|--*dir=*|--build=*) ;;
--host=*|--target=*) target=${arg#*=} ;;
-* ) echo "$0: unknown option $arg" ;;
CC=*) CC=${arg#*=} ;;
CFLAGS=*) CFLAGS=${arg#*=} ;;
CPPFLAGS=*) CPPFLAGS=${arg#*=} ;;
LDFLAGS=*) LDFLAGS=${arg#*=} ;;
CROSS_COMPILE=*) CROSS_COMPILE=${arg#*=} ;;
LIBCC=*) LIBCC=${arg#*=} ;;
*=*) ;;
*) target=$arg ;;
esac
done
for i in prefix exec_prefix bindir libdir includedir syslibdir ; do
stripdir $i
done
#
# Get a temp filename we can use
#
i=0
set -C
while : ; do i=$(($i+1))
tmpc="./conf$$-$PPID-$i.c"
2>|/dev/null > "$tmpc" && break
test "$i" -gt 50 && fail "$0: cannot create temporary file $tmpc"
done
set +C
trap 'rm "$tmpc"' EXIT INT QUIT TERM HUP
#
# Find a C compiler to use
#
printf "checking for C compiler... "
trycc ${CROSS_COMPILE}gcc
trycc ${CROSS_COMPILE}c99
trycc ${CROSS_COMPILE}cc
printf "%s\n" "$CC"
test -n "$CC" || { echo "$0: cannot find a C compiler" ; exit 1 ; }
printf "checking whether C compiler works... "
echo "typedef int x;" > "$tmpc"
if output=$($CC $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" 2>&1) ; then
printf "yes\n"
else
printf "no; compiler output follows:\n%s\n" "$output"
exit 1
fi
#
# Figure out options to force errors on unknown flags.
#
tryflag CFLAGS_TRY -Werror=unknown-warning-option
tryflag CFLAGS_TRY -Werror=unused-command-line-argument
tryldflag LDFLAGS_TRY -Werror=unknown-warning-option
tryldflag LDFLAGS_TRY -Werror=unused-command-line-argument
#
# Need to know if the compiler is gcc or clang to decide which toolchain
# wrappers to build.
#
printf "checking for C compiler family... "
cc_ver="$(LC_ALL=C $CC -v 2>&1)"
cc_family=unknown
if fnmatch '*gcc\ version*' "$cc_ver" ; then
cc_family=gcc
elif fnmatch '*clang\ version*' "$cc_ver" ; then
cc_family=clang
fi
echo "$cc_family"
#
# Figure out toolchain wrapper to build
#
if test "$wrapper" = auto -o "$wrapper" = detect ; then
echo "#include <stdlib.h>" > "$tmpc"
echo "#if ! __GLIBC__" >> "$tmpc"
echo "#error no" >> "$tmpc"
echo "#endif" >> "$tmpc"
printf "checking for toolchain wrapper to build... "
if test "$wrapper" = auto && ! $CC -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
echo "none"
elif test "$cc_family" = gcc ; then
gcc_wrapper=yes
echo "gcc"
elif test "$cc_family" = clang ; then
clang_wrapper=yes
echo "clang"
else
echo "none"
if test "$wrapper" = detect ; then
fail "$0: could not find an appropriate toolchain wrapper"
fi
fi
fi
if test "$gcc_wrapper" = yes ; then
tools="$tools tools/musl-gcc"
tool_libs="$tool_libs lib/musl-gcc.specs"
fi
if test "$clang_wrapper" = yes ; then
tools="$tools tools/musl-clang tools/ld.musl-clang"
fi
#
# Find the target architecture
#
printf "checking target system type... "
test -n "$target" || target=$($CC -dumpmachine 2>/dev/null) || target=unknown
printf "%s\n" "$target"
#
# Convert to just ARCH
#
case "$target" in
# Catch these early to simplify matching for 32-bit archs
mips64*|powerpc64*) fail "$0: unsupported target \"$target\"" ;;
arm*) ARCH=arm ;;
aarch64*) ARCH=aarch64 ;;
i?86*) ARCH=i386 ;;
x86_64-x32*|x32*|x86_64*x32) ARCH=x32 ;;
x86_64*) ARCH=x86_64 ;;
mips*) ARCH=mips ;;
microblaze*) ARCH=microblaze ;;
or1k*) ARCH=or1k ;;
powerpc*) ARCH=powerpc ;;
sh[1-9bel-]*|sh|superh*) ARCH=sh ;;
unknown) fail "$0: unable to detect target arch; try $0 --target=..." ;;
*) fail "$0: unknown or unsupported target \"$target\"" ;;
esac
#
# Try to get a conforming C99 freestanding environment
#
tryflag CFLAGS_C99FSE -std=c99
tryflag CFLAGS_C99FSE -nostdinc
tryflag CFLAGS_C99FSE -ffreestanding \
|| tryflag CFLAGS_C99FSE -fno-builtin
tryflag CFLAGS_C99FSE -fexcess-precision=standard \
|| { test "$ARCH" = i386 && tryflag CFLAGS_C99FSE -ffloat-store ; }
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tryflag CFLAGS_C99FSE -frounding-math
#
# We may use the may_alias attribute if __GNUC__ is defined, so
# if the compiler defines __GNUC__ but does not provide it,
# it must be defined away as part of the CFLAGS.
#
printf "checking whether compiler needs attribute((may_alias)) suppression... "
cat > "$tmpc" <<EOF
typedef int
#ifdef __GNUC__
__attribute__((__may_alias__))
#endif
x;
EOF
if $CC $CFLAGS_C99FSE -I./arch/$ARCH -I./include $CPPFLAGS $CFLAGS \
-c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "no\n"
else
printf "yes\n"
CFLAGS_C99FSE="$CFLAGS_C99FSE -D__may_alias__="
fi
#
# Check for options to disable stack protector, which needs to be
# disabled for a few early-bootstrap translation units. If not found,
# this is not an error; we assume the toolchain does not do ssp.
#
tryflag CFLAGS_NOSSP -fno-stack-protector
#
# Check for options that may be needed to prevent the compiler from
# generating self-referential versions of memcpy,, memmove, memcmp,
# and memset. Really, we should add a check to determine if this
# option is sufficient, and if not, add a macro to cripple these
# functions with volatile...
#
tryflag CFLAGS_MEMOPS -fno-tree-loop-distribute-patterns
#
# Enable debugging if requessted.
#
test "$debug" = yes && CFLAGS_AUTO=-g
Build process uses script to add CFI directives to x86 asm Some functions implemented in asm need to use EBP for purposes other than acting as a frame pointer. (Notably, it is used for the 6th argument to syscalls with 6 arguments.) Without frame pointers, GDB can only show backtraces if it gets CFI information from a .debug_frame or .eh_frame ELF section. Rather than littering our asm with ugly .cfi directives, use an awk script to insert them in the right places during the build process, so GDB can keep track of where the current stack frame is relative to the stack pointer. This means GDB can produce beautiful stack traces at any given point when single-stepping through asm functions. Additionally, when registers are saved on the stack and later overwritten, emit ..cfi directives so GDB will know where they were saved relative to the stack pointer. This way, when you look back up the stack from within an asm function, you can still reliably print the values of local variables in the caller. If this awk script were to understand every possible wild and crazy contortion that an asm programmer can do with the stack and registers, and always emit the exact ..cfi directives needed for GDB to know what the register values were in the preceding stack frame, it would necessarily be as complex as a full x86 emulator. That way lies madness. Hence, we assume that the stack pointer will _only_ ever be adjusted using push/pop or else add/sub with a constant. We do not attempt to detect every possible way that a register value could be saved for later use, just the simple and common ways. Thanks to Szabolcs Nagy for suggesting numerous improvements to this code.
2015-07-10 16:03:24 +03:00
#
# Preprocess asm files to add extra debugging information if debug is
# enabled, our assembler supports the needed directives, and the
# preprocessing script has been written for our architecture.
#
printf "checking whether we should preprocess assembly to add debugging information... "
if fnmatch '-g*|*\ -g*' "$CFLAGS_AUTO $CFLAGS" &&
test -f "tools/add-cfi.$ARCH.awk" &&
printf ".file 1 \"srcfile.s\"\n.line 1\n.cfi_startproc\n.cfi_endproc" | $CC -g -x assembler -c -o /dev/null 2>/dev/null -
then
ADD_CFI=yes
else
ADD_CFI=no
fi
printf "%s\n" "$ADD_CFI"
#
# Possibly add a -O option to CFLAGS and select modules to optimize with
# -O3 based on the status of --enable-optimize and provided CFLAGS.
#
printf "checking for optimization settings... "
case "x$optimize" in
xauto)
if fnmatch '-O*|*\ -O*' "$CFLAGS_AUTO $CFLAGS" ; then
printf "using provided CFLAGS\n" ;optimize=no
else
printf "using defaults\n" ; optimize=yes
fi
;;
xsize|xnone) printf "minimize size\n" ; optimize=size ;;
xno|x) printf "disabled\n" ; optimize=no ;;
*) printf "custom\n" ;;
esac
test "$optimize" = no || tryflag CFLAGS_AUTO -Os || tryflag CFLAGS_AUTO -O2
test "$optimize" = yes && optimize="internal,malloc,string"
if fnmatch 'no|size' "$optimize" ; then :
else
printf "components to be optimized for speed:"
while test "$optimize" ; do
case "$optimize" in
*,*) this=${optimize%%,*} optimize=${optimize#*,} ;;
*) this=$optimize optimize=
esac
printf " $this"
case "$this" in
*/*.c) ;;
*/*) this=$this*.c ;;
*) this=$this/*.c ;;
esac
OPTIMIZE_GLOBS="$OPTIMIZE_GLOBS $this"
done
OPTIMIZE_GLOBS=${OPTIMIZE_GLOBS# }
printf "\n"
fi
# Always try -pipe
tryflag CFLAGS_AUTO -pipe
#
# If debugging is disabled, omit frame pointer. Modern GCC does this
# anyway on most archs even when debugging is enabled since the frame
# pointer is no longer needed for debugging.
#
if fnmatch '-g*|*\ -g*' "$CFLAGS_AUTO $CFLAGS" ; then :
else
tryflag CFLAGS_AUTO -fomit-frame-pointer
fi
#
# Modern GCC wants to put DWARF tables (used for debugging and
# unwinding) in the loaded part of the program where they are
# unstrippable. These options force them back to debug sections (and
# cause them not to get generated at all if debugging is off).
#
tryflag CFLAGS_AUTO -fno-unwind-tables
tryflag CFLAGS_AUTO -fno-asynchronous-unwind-tables
#
# The GNU toolchain defaults to assuming unmarked files need an
# executable stack, potentially exposing vulnerabilities in programs
# linked with such object files. Fix this.
#
tryflag CFLAGS_AUTO -Wa,--noexecstack
#
# On x86, make sure we don't have incompatible instruction set
# extensions enabled by default. This is bad for making static binaries.
# We cheat and use i486 rather than i386 because i386 really does not
# work anyway (issues with atomic ops).
# Some build environments pass -march and -mtune options via CC, so
# check both CC and CFLAGS.
#
if test "$ARCH" = "i386" ; then
fnmatch '-march=*|*\ -march=*' "$CC $CFLAGS" || tryldflag CFLAGS_AUTO -march=i486
fnmatch '-mtune=*|*\ -mtune=*' "$CC $CFLAGS" || tryldflag CFLAGS_AUTO -mtune=generic
fi
#
# Even with -std=c99, gcc accepts some constructs which are constraint
# violations. We want to treat these as errors regardless of whether
# other purely stylistic warnings are enabled -- especially implicit
# function declarations, which are a dangerous programming error.
#
tryflag CFLAGS_AUTO -Werror=implicit-function-declaration
tryflag CFLAGS_AUTO -Werror=implicit-int
tryflag CFLAGS_AUTO -Werror=pointer-sign
tryflag CFLAGS_AUTO -Werror=pointer-arith
if test "x$warnings" = xyes ; then
tryflag CFLAGS_AUTO -Wall
tryflag CFLAGS_AUTO -Wno-parentheses
tryflag CFLAGS_AUTO -Wno-uninitialized
tryflag CFLAGS_AUTO -Wno-missing-braces
tryflag CFLAGS_AUTO -Wno-unused-value
tryflag CFLAGS_AUTO -Wno-unused-but-set-variable
tryflag CFLAGS_AUTO -Wno-unknown-pragmas
tryflag CFLAGS_AUTO -Wno-pointer-to-int-cast
fi
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if test "x$visibility" = xauto ; then
# This test checks toolchain support for several things:
# - the -include option
# - the attributes/pragmas used in vis.h
# - linking code that takes the address of protected symbols
printf "checking whether global visibility preinclude works... "
echo 'int (*fp)(void);' > "$tmpc"
echo 'int foo(void) { }' >> "$tmpc"
echo 'int bar(void) { fp = foo; return foo(); }' >> "$tmpc"
if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS \
-DSHARED -fPIC -I./src/internal -include vis.h \
-nostdlib -shared -Wl,-Bsymbolic-functions \
-o /dev/null "$tmpc" >/dev/null 2>&1 ; then
visibility=yes
else
visibility=no
fi
printf "%s\n" "$visibility"
fi
2015-04-23 05:11:48 +03:00
if test "x$visibility" = xyes ; then
CFLAGS_AUTO="$CFLAGS_AUTO -include vis.h"
CFLAGS_AUTO="${CFLAGS_AUTO# }"
fi
# Some patched GCC builds have these defaults messed up...
tryldflag LDFLAGS_AUTO -Wl,--hash-style=both
# Prevent linking if there are undefined symbols; if any exist,
# libc.so will crash at runtime during relocation processing.
# The common way this can happen is failure to link the compiler
# runtime library; implementation error is also a possibility.
tryldflag LDFLAGS_AUTO -Wl,--no-undefined
test "$shared" = "no" || {
# Disable dynamic linking if ld is broken and can't do -Bsymbolic-functions
LDFLAGS_DUMMY=
tryldflag LDFLAGS_DUMMY -Wl,-Bsymbolic-functions || {
test "$shared" = "yes" && fail "$0: error: linker cannot build shared library"
printf "warning: disabling dynamic linking support\n"
shared=no
}
}
# Find compiler runtime library
test -z "$LIBCC" && tryldflag LIBCC -lgcc && tryldflag LIBCC -lgcc_eh
test -z "$LIBCC" && tryldflag LIBCC -lcompiler_rt
test -z "$LIBCC" && try_libcc=`$CC -print-file-name=libpcc.a 2>/dev/null` \
&& tryldflag LIBCC "$try_libcc"
printf "using compiler runtime libraries: %s\n" "$LIBCC"
# Figure out arch variants for archs with variants
SUBARCH=
t="$CFLAGS_C99FSE $CPPFLAGS $CFLAGS"
if test "$ARCH" = "x86_64" ; then
trycppif __ILP32__ "$t" && ARCH=x32
fi
if test "$ARCH" = "arm" ; then
trycppif __ARMEB__ "$t" && SUBARCH=${SUBARCH}eb
trycppif __ARM_PCS_VFP "$t" && SUBARCH=${SUBARCH}hf
fi
if test "$ARCH" = "aarch64" ; then
trycppif __AARCH64EB__ "$t" && SUBARCH=${SUBARCH}_be
fi
if test "$ARCH" = "mips" ; then
trycppif "_MIPSEL || __MIPSEL || __MIPSEL__" "$t" && SUBARCH=${SUBARCH}el
trycppif __mips_soft_float "$t" && SUBARCH=${SUBARCH}-sf
fi
test "$ARCH" = "microblaze" && trycppif __MICROBLAZEEL__ "$t" \
&& SUBARCH=${SUBARCH}el
if test "$ARCH" = "sh" ; then
trycppif __BIG_ENDIAN__ "$t" && SUBARCH=${SUBARCH}eb
if trycppif "__SH_FPU_ANY__ || __SH4__" "$t" ; then
# Some sh configurations are broken and replace double with float
# rather than using softfloat when the fpu is present but only
# supports single precision. Reject them.
printf "checking whether compiler's double type is IEEE double... "
echo 'typedef char dblcheck[(int)sizeof(double)-5];' > "$tmpc"
if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
else
printf "no\n"
fail "$0: error: compiler's floating point configuration is unsupported"
fi
else
SUBARCH=${SUBARCH}-nofpu
fi
if trycppif __SH_FDPIC__ "$t" ; then
SUBARCH=${SUBARCH}-fdpic
fi
fi
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test "$SUBARCH" \
&& printf "configured for %s variant: %s\n" "$ARCH" "$ARCH$SUBARCH"
case "$ARCH$SUBARCH" in
arm) ASMSUBARCH=el ;;
*) ASMSUBARCH=$SUBARCH ;;
esac
#
# Some archs (powerpc) have different possible long double formats
# that the compiler can be configured for. The logic for whether this
# is supported is in bits/float.h; in general, it is not. We need to
# check for mismatches here or code in printf, strotd, and scanf will
# be dangerously incorrect because it depends on (1) the macros being
# correct, and (2) IEEE semantics.
#
printf "checking whether compiler's long double definition matches float.h... "
echo '#include <float.h>' > "$tmpc"
echo '#if LDBL_MANT_DIG == 53' >> "$tmpc"
echo 'typedef char ldcheck[9-(int)sizeof(long double)];' >> "$tmpc"
echo '#endif' >> "$tmpc"
if $CC $CFLAGS_C99FSE -I./arch/$ARCH -I./include $CPPFLAGS $CFLAGS \
-c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
else
printf "no\n"
fail "$0: error: unsupported long double type"
fi
printf "creating config.mak... "
cmdline=$(quote "$0")
for i ; do cmdline="$cmdline $(quote "$i")" ; done
exec 3>&1 1>config.mak
cat << EOF
# This version of config.mak was generated by:
# $cmdline
# Any changes made here will be lost if configure is re-run
ARCH = $ARCH
SUBARCH = $SUBARCH
ASMSUBARCH = $ASMSUBARCH
prefix = $prefix
exec_prefix = $exec_prefix
bindir = $bindir
libdir = $libdir
includedir = $includedir
syslibdir = $syslibdir
CC = $CC
CFLAGS = $CFLAGS_AUTO $CFLAGS
CFLAGS_C99FSE = $CFLAGS_C99FSE
CFLAGS_MEMOPS = $CFLAGS_MEMOPS
CFLAGS_NOSSP = $CFLAGS_NOSSP
CPPFLAGS = $CPPFLAGS
LDFLAGS = $LDFLAGS_AUTO $LDFLAGS
CROSS_COMPILE = $CROSS_COMPILE
LIBCC = $LIBCC
OPTIMIZE_GLOBS = $OPTIMIZE_GLOBS
ALL_TOOLS = $tools
TOOL_LIBS = $tool_libs
Build process uses script to add CFI directives to x86 asm Some functions implemented in asm need to use EBP for purposes other than acting as a frame pointer. (Notably, it is used for the 6th argument to syscalls with 6 arguments.) Without frame pointers, GDB can only show backtraces if it gets CFI information from a .debug_frame or .eh_frame ELF section. Rather than littering our asm with ugly .cfi directives, use an awk script to insert them in the right places during the build process, so GDB can keep track of where the current stack frame is relative to the stack pointer. This means GDB can produce beautiful stack traces at any given point when single-stepping through asm functions. Additionally, when registers are saved on the stack and later overwritten, emit ..cfi directives so GDB will know where they were saved relative to the stack pointer. This way, when you look back up the stack from within an asm function, you can still reliably print the values of local variables in the caller. If this awk script were to understand every possible wild and crazy contortion that an asm programmer can do with the stack and registers, and always emit the exact ..cfi directives needed for GDB to know what the register values were in the preceding stack frame, it would necessarily be as complex as a full x86 emulator. That way lies madness. Hence, we assume that the stack pointer will _only_ ever be adjusted using push/pop or else add/sub with a constant. We do not attempt to detect every possible way that a register value could be saved for later use, just the simple and common ways. Thanks to Szabolcs Nagy for suggesting numerous improvements to this code.
2015-07-10 16:03:24 +03:00
ADD_CFI = $ADD_CFI
EOF
test "x$static" = xno && echo "STATIC_LIBS ="
test "x$shared" = xno && echo "SHARED_LIBS ="
test "x$cc_family" = xgcc && echo 'WRAPCC_GCC = $(CC)'
test "x$cc_family" = xclang && echo 'WRAPCC_CLANG = $(CC)'
exec 1>&3 3>&-
printf "done\n"