summaryrefslogtreecommitdiff
path: root/scripts/build/cc/100-gcc.sh
blob: 48f5122027359f480b2aa51c8df27f5ed50669a7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
# This file adds the function to build the gcc C compiler
# Copyright 2007 Yann E. MORIN
# Licensed under the GPL v2. See COPYING in the root of this package

# Download gcc
do_gcc_get() {
    local linaro_version=""
    local linaro_series=""

    if [ "${CT_CC_GCC_CUSTOM}" = "y" ]; then
        CT_GetCustom "gcc" "${CT_CC_GCC_CUSTOM_VERSION}" \
            "${CT_CC_GCC_CUSTOM_LOCATION}"
    else
        case "${CT_CC_GCC_VERSION}" in
            linaro-*)
                CT_GetLinaro "gcc" "${CT_CC_GCC_VERSION}"
                ;;
            *)
                # The official gcc hosts put gcc under a gcc/release/ directory,
                # whereas the mirrors put it in the gcc/ directory.
                CT_GetFile "gcc-${CT_CC_GCC_VERSION}" \
                           {http,ftp,https}://ftp.gnu.org/gnu/gcc/gcc-${CT_CC_GCC_VERSION} \
                           ftp://{gcc.gnu.org,sourceware.org}/pub/gcc/releases/gcc-${CT_CC_GCC_VERSION}
                ;;
        esac
    fi # ! custom location
    # Starting with GCC 4.3, ecj is used for Java, and will only be
    # built if the configure script finds ecj.jar at the top of the
    # GCC source tree, which will not be there unless we get it and
    # put it there ourselves
    if [ "${CT_CC_LANG_JAVA_USE_ECJ}" = "y" ]; then
        CT_GetFile ecj-latest .jar http://mirrors.kernel.org/sourceware/java/ \
                                   http://crosstool-ng.org/pub/java           \
                                   ftp://gcc.gnu.org/pub/java                 \
                                   ftp://sourceware.org/pub/java
    fi
}

# Extract gcc
do_gcc_extract() {
    CT_Extract "gcc-${CT_CC_GCC_VERSION}"
    CT_Patch "gcc" "${CT_CC_GCC_VERSION}"

    # Copy ecj-latest.jar to ecj.jar at the top of the GCC source tree
    if [ "${CT_CC_LANG_JAVA_USE_ECJ}" = "y"                     \
         -a ! -f "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/ecj.jar"   \
       ]; then
        CT_DoExecLog ALL cp -v "${CT_TARBALLS_DIR}/ecj-latest.jar" "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/ecj.jar"
    fi

    if [ -n "${CT_ARCH_XTENSA_CUSTOM_NAME}" ]; then
        CT_ConfigureXtensa "gcc" "${CT_CC_GCC_VERSION}"
    fi
}

#------------------------------------------------------------------------------
# This function builds up the set of languages to enable
# No argument expected, returns the comma-separated language list on stdout
cc_gcc_lang_list() {
    local lang_list

    lang_list="c"
    [ "${CT_CC_LANG_CXX}" = "y"      ] && lang_list+=",c++"
    [ "${CT_CC_LANG_FORTRAN}" = "y"  ] && lang_list+=",fortran"
    [ "${CT_CC_LANG_ADA}" = "y"      ] && lang_list+=",ada"
    [ "${CT_CC_LANG_JAVA}" = "y"     ] && lang_list+=",java"
    [ "${CT_CC_LANG_OBJC}" = "y"     ] && lang_list+=",objc"
    [ "${CT_CC_LANG_OBJCXX}" = "y"   ] && lang_list+=",obj-c++"
    [ "${CT_CC_LANG_GOLANG}" = "y"   ] && lang_list+=",go"
    lang_list+="${CT_CC_LANG_OTHERS:+,${CT_CC_LANG_OTHERS}}"

    printf "%s" "${lang_list}"
}

#------------------------------------------------------------------------------
# Return a value of a requested GCC spec
cc_gcc_get_spec() {
    local spec=$1
    local cc_and_cflags=$2

    # GCC does not provide a facility to request a value of a spec string.
    # The only way to do that I found was to augment the spec file with
    # some dummy suffix handler that does nothing except printing it.
    touch temp-input.spec_eval
    {
        echo ".spec_eval:"
        echo "echo %(${spec})"
    } > "tmp-specs-${spec}"
    ${cc_and_cflags} -specs="tmp-specs-${spec}" -E temp-input.spec_eval
}

#------------------------------------------------------------------------------
# Report the type of a GCC option
cc_gcc_classify_opt() {
    # Options present in multiple architectures
    case "${1}" in
        -march=*) echo "arch"; return;;
        -mabi=*) echo "abi"; return;;
        -mcpu=*|-mmcu=*) echo "cpu"; return;;
        -mtune=*) echo "tune"; return;;
        -mfpu=*) echo "fpu"; return;;
        -mhard-float|-msoft-float|-mno-soft-float|-mno-float|-mfloat-abi=*|\
            -mfpu|-mno-fpu) echo "float"; return;;
        -EB|-EL|-mbig-endian|-mlittle-endian|-mbig|-mlittle|-meb|-mel|-mb|-ml) echo "endian"; return;;
        -mthumb|-marm) echo "mode"; return;;
    esac

    # Arch-specific options and aliases
    case "${CT_ARCH}" in
        m68k)
            case "${1}" in
                -m68881) echo "float"; return;;
                -m5[234]*|-mcfv4e) echo "cpu"; return;;
                -m68*|-mc68*) echo "arch"; return;;
            esac
            ;;
        mips)
            case "${1}" in
                -mips[1234]|-mips32|-mips32r*|-mips64|-mips64r*) echo "cpu"; return;;
            esac
            ;;
        sh)
            case "${1}" in
                -m[12345]*) echo "cpu"; return;;
            esac
    esac

    # All tried and failed
    echo "unknown"
}

#------------------------------------------------------------------------------
# This function lists the multilibs configured in the compiler (even if multilib
# is disabled - so that it lists the default GCC/OS directory, which may differ
# from the default 'lib'). It then performs a few multilib checks/quirks:
#
# 1. On SuperH target, configuring with default CPU (e.g. by supplying the target
# name as 'sh4', which is what CT-NG does) results in the compiler being unable to
# run if that same switch is passed to the resulting gcc (e.g. 'gcc -m4'). The reason
# for this behavior is that the script that determines the sysroot suffix is not
# aware of the default multilib selection, so it generates <sysroot>/m4 as the
# suffixed sysroot. But the main driver, knowing that -m4 is the default, does not
# even attempt to fall back to the non-suffixed sysroot (as it does with non-default
# multilibs) - as a result, gcc fails to find any library if invoked with -m4.
# The right solution would be to drop the default CPU from the multilib list
# completely, or make the print-sysroot-suffix.sh script aware of the defaults
# (which is not easy, as the defaults are not in tmake_file, but rather in tm_file...)
#
# 2. On MIPS target, gcc (or rather, ld, which it invokes under the hood) chokes
# if supplied with two -mabi=* options. I.e., 'gcc -mabi=n32' and 'gcc -mabi=32' both
# work, but 'gcc -mabi=32 -mabi=n32' produces an internal error in ld. Thus we do
# not supply target's CFLAGS in multilib builds - and after compiling pass-1 gcc,
# attempt to determine which CFLAGS need to be filtered out.
cc_gcc_multilib_housekeeping() {
    local cc host
    local flags osdir dir multilibs i f
    local multilib_defaults
    local suffix sysroot base lnk
    local ml_arch ml_abi ml_cpu ml_tune ml_fpu ml_float ml_endian ml_mode ml_unknown ml
    local new_cflags

    for arg in "$@"; do
        eval "${arg// /\\ }"
    done

    if [ \( "${CT_CANADIAN}" = "y" -o "${CT_CROSS_NATIVE}" = "y" \) -a "${host}" = "${CT_HOST}" ]; then
        CT_DoLog EXTRA "Canadian Cross/Cross-native unable to confirm multilibs configuration "\
            "directly; will use build-compiler for housekeeping."
        # Since we cannot run the desired compiler, substitute build-CC with the assumption
        # that the host-CC is configured in the same way.
        cc="${CT_BUILDTOOLS_PREFIX_DIR}/bin/${CT_TARGET}-${CT_CC}"
    fi

    # sed: prepend dashes or do nothing if default is empty string
    multilib_defaults=( $( cc_gcc_get_spec multilib_defaults "${cc}" | \
        sed 's/\(^\|[[:space:]]\+\)\([^[:space:]]\)/ -\2/g' ) )
    CT_DoLog EXTRA "gcc default flags: '${multilib_defaults}'"

    multilibs=( $( "${cc}" -print-multi-lib ) )
    if [ ${#multilibs[@]} -ne 0 ]; then
        CT_DoLog EXTRA "gcc configured with these multilibs (including the default):"
        for i in "${multilibs[@]}"; do
            dir="lib/${i%%;*}"
            flags="${i#*;}"
            flags=${flags//@/ -}
            flags=$( echo ${flags} )
            osdir="lib/"$( "${cc}" -print-multi-os-directory ${flags} )
            CT_SanitizeVarDir dir osdir
            CT_DoLog EXTRA "   '${flags}' --> ${dir} (gcc)   ${osdir} (os)"
            for f in ${flags}; do
                eval ml_`cc_gcc_classify_opt ${f}`=seen
            done
        done
    else
        CT_DoLog WARN "no multilib configuration: GCC unusable?"
    fi

    # Filtering out some of the options provided in CT-NG config. Then *prepend*
    # them to CT_TARGET_CFLAGS, like scripts/crosstool-NG.sh does. Zero out
    # the stashed MULTILIB flags so that we don't process them again in the passes
    # that follow.
    CT_DoLog DEBUG "Configured target CFLAGS: '${CT_ARCH_TARGET_CFLAGS_MULTILIB}'"
    ml_unknown= # Pass through anything we don't know about
    for f in ${CT_ARCH_TARGET_CFLAGS_MULTILIB}; do
        eval ml=\$ml_`cc_gcc_classify_opt ${f}`
        if [ "${ml}" != "seen" ]; then
            new_cflags="${new_cflags} ${f}"
        fi
    done
    CT_DoLog DEBUG "Filtered target CFLAGS: '${new_cflags}'"
    CT_EnvModify CT_TARGET_CFLAGS "${new_cflags} ${CT_TARGET_CFLAGS}"
    CT_EnvModify CT_ARCH_TARGET_CFLAGS_MULTILIB ""

    # Currently, the only LDFLAGS are endianness-related
    CT_DoLog DEBUG "Configured target LDFLAGS: '${CT_ARCH_TARGET_LDFLAGS_MULTILIB}'"
    if [ "${ml_endian}" != "seen" ]; then
        CT_EnvModify CT_TARGET_LDFLAGS "${CT_ARCH_TARGET_LDFLAGS_MULTILIB} ${CT_TARGET_LDFLAGS}"
        CT_EnvModify CT_ARCH_TARGET_LDFLAGS_MULTILIB ""
    fi
    CT_DoLog DEBUG "Filtered target LDFLAGS: '${CT_ARCH_TARGET_LDFLAGS_MULTILIB}'"

    # Sysroot suffix fixup for the multilib default.
    suffix=$( cc_gcc_get_spec sysroot_suffix_spec "${cc} ${multilib_defaults}" )
    if [ -n "${suffix}" ]; then
        base=${suffix%/*}
        sysroot=$( "${cc}" -print-sysroot )
        if [ -n "${base}" ]; then
            CT_DoExecLog ALL mkdir -p "${sysroot}${base}"
            lnk=$( echo "${base#/}" | sed -e 's,[^/]*,..,g' )
        else
            lnk=.
        fi
        CT_DoExecLog ALL rm -f "${sysroot}${suffix}"
        CT_DoExecLog ALL ln -sfv "${lnk}" "${sysroot}${suffix}"
    fi
}

#------------------------------------------------------------------------------
# Core gcc pass 1
do_gcc_core_pass_1() {
    local -a core_opts

    if [ "${CT_CC_CORE_PASS_1_NEEDED}" != "y" ]; then
        return 0
    fi

    core_opts+=( "mode=static" )
    core_opts+=( "host=${CT_BUILD}" )
    core_opts+=( "complibs=${CT_BUILDTOOLS_PREFIX_DIR}" )
    core_opts+=( "prefix=${CT_BUILDTOOLS_PREFIX_DIR}" )
    core_opts+=( "cflags=${CT_CFLAGS_FOR_BUILD}" )
    core_opts+=( "ldflags=${CT_LDFLAGS_FOR_BUILD}" )
    core_opts+=( "lang_list=c" )
    core_opts+=( "build_step=core1" )

    CT_DoStep INFO "Installing pass-1 core C gcc compiler"
    CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-gcc-core-pass-1"

    do_gcc_core_backend "${core_opts[@]}"

    CT_Popd
    CT_EndStep
}

# Core gcc pass 2
do_gcc_core_pass_2() {
    local -a core_opts

    if [ "${CT_CC_CORE_PASS_2_NEEDED}" != "y" ]; then
        return 0
    fi

    # Common options:
    core_opts+=( "host=${CT_BUILD}" )
    core_opts+=( "prefix=${CT_BUILDTOOLS_PREFIX_DIR}" )
    core_opts+=( "complibs=${CT_BUILDTOOLS_PREFIX_DIR}" )
    core_opts+=( "cflags=${CT_CFLAGS_FOR_BUILD}" )
    core_opts+=( "ldflags=${CT_LDFLAGS_FOR_BUILD}" )
    core_opts+=( "lang_list=c" )
    core_opts+=( "build_step=core2" )

    # Different conditions are at stake here:
    #   - In case the threading model is NPTL, we need a shared-capable core
    #     gcc; in all other cases, we need a static-only core gcc.
    #   - In case the threading model is NPTL or win32, or gcc is 4.3 or
    #     later, we need to build libgcc
    case "${CT_THREADS}" in
        nptl)
            core_opts+=( "mode=shared" )
            core_opts+=( "build_libgcc=yes" )
            ;;
        win32)
            core_opts+=( "mode=static" )
            core_opts+=( "build_libgcc=yes" )
            ;;
        *)
            core_opts+=( "mode=static" )
            core_opts+=( "build_libgcc=yes" )
            ;;
    esac

    CT_DoStep INFO "Installing pass-2 core C gcc compiler"
    CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-gcc-core-pass-2"

    do_gcc_core_backend "${core_opts[@]}"

    CT_Popd
    CT_EndStep
}

#------------------------------------------------------------------------------
# Build core gcc
# This function is used to build the core C compiler.
# Usage: do_gcc_core_backend param=value [...]
#   Parameter           : Definition                                : Type      : Default
#   mode                : build a 'static', 'shared' or 'baremetal' : string    : (none)
#   host                : the machine the core will run on          : tuple     : (none)
#   prefix              : dir prefix to install into                : dir       : (none)
#   complibs            : dir where complibs are installed          : dir       : (none)
#   lang_list           : the list of languages to build            : string    : (empty)
#   build_libgcc        : build libgcc or not                       : bool      : no
#   build_libstdcxx     : build libstdc++ or not                    : bool      : no
#   build_libgfortran   : build libgfortran or not                  : bool      : no
#   build_staticlinked  : build statically linked or not            : bool      : no
#   build_manuals       : whether to build manuals or not           : bool      : no
#   cflags              : cflags to use                             : string    : (empty)
#   ldflags             : ldflags to use                            : string    : (empty)
#   build_step          : build step 'core1', 'core2', 'gcc_build'
#                         or 'gcc_host'                             : string    : (none)
# Usage: do_gcc_core_backend mode=[static|shared|baremetal] build_libgcc=[yes|no] build_staticlinked=[yes|no]
do_gcc_core_backend() {
    local mode
    local build_libgcc=no
    local build_libstdcxx=no
    local build_libgfortran=no
    local build_staticlinked=no
    local build_manuals=no
    local host
    local prefix
    local complibs
    local lang_list
    local cflags
    local ldflags
    local build_step
    local log_txt
    local tmp
    local -a host_libstdcxx_flags
    local -a extra_config
    local -a core_LDFLAGS
    local -a core_targets
    local -a core_targets_all
    local -a core_targets_install
    local -a extra_user_config
    local arg

    for arg in "$@"; do
        eval "${arg// /\\ }"
    done

    # This function gets called in case of a bare metal compiler for the final gcc, too.
    case "${build_step}" in
        core1|core2)
            CT_DoLog EXTRA "Configuring core C gcc compiler"
            log_txt="gcc"
            extra_user_config=( "${CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY[@]}" )
            ;;
        gcc_build|gcc_host)
            CT_DoLog EXTRA "Configuring final gcc compiler"
            extra_user_config=( "${CT_CC_GCC_EXTRA_CONFIG_ARRAY[@]}" )
            log_txt="final gcc compiler"
            if [ "${CT_CC_GCC_TARGET_FINAL}" = "y" ]; then
                # to inhibit the libiberty and libgcc tricks later on
                build_libgcc=no
            fi
            ;;
        *)
            CT_Abort "Internal Error: 'build_step' must be one of: 'core1', 'core2', 'gcc_build' or 'gcc_host', not '${build_step:-(empty)}'"
            ;;
    esac

    case "${mode}" in
        static)
            extra_config+=("--with-newlib")
            extra_config+=("--enable-threads=no")
            extra_config+=("--disable-shared")
            ;;
        shared)
            extra_config+=("--enable-shared")
            ;;
        baremetal)
            extra_config+=("--with-newlib")
            extra_config+=("--enable-threads=no")
            extra_config+=("--disable-shared")
            ;;
        *)
            CT_Abort "Internal Error: 'mode' must be one of: 'static', 'shared' or 'baremetal', not '${mode:-(empty)}'"
            ;;
    esac

    # This is only needed when building libstdc++ in a canadian environment with
    # this function being used for final step (i.e., when building for bare metal).
    if [ "${build_step}" = "gcc_build" ]; then
        CT_DoLog DEBUG "Copying headers to install area of core C compiler"
        CT_DoExecLog ALL cp -a "${CT_HEADERS_DIR}" "${prefix}/${CT_TARGET}/include"
    fi

    for tmp in ARCH ABI CPU TUNE FPU FLOAT; do
        eval tmp="\${CT_ARCH_WITH_${tmp}}"
        if [ -n "${tmp}" ]; then
            extra_config+=("${tmp}")
        fi
    done

    extra_config+=("--with-pkgversion=${CT_PKGVERSION}")
    [ -n "${CT_TOOLCHAIN_BUGURL}" ] && extra_config+=("--with-bugurl=${CT_TOOLCHAIN_BUGURL}")

    if [ "${CT_CC_CXA_ATEXIT}" = "y" ]; then
        extra_config+=("--enable-__cxa_atexit")
    else
        extra_config+=("--disable-__cxa_atexit")
    fi

    if [ -n "${CT_CC_GCC_ENABLE_CXX_FLAGS}" \
            -a "${mode}" = "baremetal" ]; then
        extra_config+=("--enable-cxx-flags=${CT_CC_GCC_ENABLE_CXX_FLAGS}")
    fi

    extra_config+=(--disable-libgomp)
    extra_config+=(--disable-libmudflap)
    extra_config+=(--disable-libmpx)

    if [ "${CT_CC_GCC_LIBSSP}" = "y" ]; then
        extra_config+=(--enable-libssp)
    else
        extra_config+=(--disable-libssp)
    fi
    if [ "${CT_CC_GCC_LIBQUADMATH}" = "y" ]; then
        extra_config+=(--enable-libquadmath)
        extra_config+=(--enable-libquadmath-support)
    else
        extra_config+=(--disable-libquadmath)
        extra_config+=(--disable-libquadmath-support)
    fi

    core_LDFLAGS+=("${ldflags}")

    # *** WARNING ! ***
    # Keep this full if-else-if-elif-fi-fi block in sync
    # with the same block in do_gcc_backend, below.
    if [ "${build_staticlinked}" = "yes" ]; then
        core_LDFLAGS+=("-static")
        host_libstdcxx_flags+=("-static-libgcc")
        host_libstdcxx_flags+=("-Wl,-Bstatic,-lstdc++")
        host_libstdcxx_flags+=("-lm")
        # Companion libraries are build static (eg !shared), so
        # the libstdc++ is not pulled automatically, although it
        # is needed. Shoe-horn it in our LDFLAGS
        # Ditto libm on some Fedora boxen
        core_LDFLAGS+=("-lstdc++")
        core_LDFLAGS+=("-lm")
    else
        if [ "${CT_CC_GCC_STATIC_LIBSTDCXX}" = "y" ]; then
            # this is from CodeSourcery arm-2010q1-202-arm-none-linux-gnueabi.src.tar.bz2
            # build script
            # INFO: if the host gcc is gcc-4.5 then presumably we could use -static-libstdc++,
            #       see http://gcc.gnu.org/ml/gcc-patches/2009-06/msg01635.html
            host_libstdcxx_flags+=("-static-libgcc")
            host_libstdcxx_flags+=("-Wl,-Bstatic,-lstdc++,-Bdynamic")
            host_libstdcxx_flags+=("-lm")
        fi
        # When companion libraries are build static (eg !shared),
        # the libstdc++ is not pulled automatically, although it
        # is needed. Shoe-horn it in our LDFLAGS
        # Ditto libm on some Fedora boxen
        core_LDFLAGS+=("-lstdc++")
        core_LDFLAGS+=("-lm")
    fi

    extra_config+=("--with-gmp=${complibs}")
    extra_config+=("--with-mpfr=${complibs}")
    extra_config+=("--with-mpc=${complibs}")
    if [ "${CT_CC_GCC_USE_GRAPHITE}" = "y" ]; then
        if [ "${CT_ISL}" = "y" ]; then
            extra_config+=("--with-isl=${complibs}")
        fi
        if [ "${CT_CLOOG}" = "y" ]; then
            extra_config+=("--with-cloog=${complibs}")
        fi
    else
        extra_config+=("--with-isl=no")
        extra_config+=("--with-cloog=no")
    fi
    if [ "${CT_CC_GCC_USE_LTO}" = "y" ]; then
        extra_config+=("--enable-lto")
    else
        extra_config+=("--disable-lto")
    fi

    if [ ${#host_libstdcxx_flags[@]} -ne 0 ]; then
        extra_config+=("--with-host-libstdcxx=${host_libstdcxx_flags[*]}")
    fi

    if [ "${CT_CC_GCC_ENABLE_TARGET_OPTSPACE}" = "y" ]; then
        extra_config+=("--enable-target-optspace")
    fi
    if [ "${CT_CC_GCC_DISABLE_PCH}" = "y" ]; then
        extra_config+=("--disable-libstdcxx-pch")
    fi

    case "${CT_CC_GCC_LDBL_128}" in
        y)  extra_config+=("--with-long-double-128");;
        m)  ;;
        "") extra_config+=("--without-long-double-128");;
    esac

    if [ "${CT_CC_GCC_BUILD_ID}" = "y" ]; then
        extra_config+=( --enable-linker-build-id )
    fi

    case "${CT_CC_GCC_LNK_HASH_STYLE}" in
        "") ;;
        *)  extra_config+=( "--with-linker-hash-style=${CT_CC_GCC_LNK_HASH_STYLE}" );;
    esac

    case "${CT_CC_GCC_DEC_FLOATS}" in
        "") ;;
        *)  extra_config+=( "--enable-decimal-float=${CT_CC_GCC_DEC_FLOATS}" );;
    esac

    case "${CT_ARCH}" in
        mips)
            case "${CT_CC_GCC_mips_llsc}" in
                y)  extra_config+=( --with-llsc );;
                m)  ;;
                *)  extra_config+=( --without-llsc );;
            esac
            case "${CT_CC_GCC_mips_synci}" in
                y)  extra_config+=( --with-synci );;
                m)  ;;
                *)  extra_config+=( --without-synci );;
            esac
            if [ "${CT_CC_GCC_mips_plt}" ]; then
                extra_config+=( --with-mips-plt )
            fi
            ;; # ARCH is mips
    esac

    if [ "${CT_TOOLCHAIN_ENABLE_NLS}" = "y" ]; then
        extra_config+=("--with-libintl-prefix=${complibs}")
    else
        extra_config+=("--disable-nls")
    fi

    if [ "${CT_CC_GCC_SYSTEM_ZLIB}" = "y" ]; then
        extra_config+=("--with-system-zlib")
    fi

    # Some versions of gcc have a defective --enable-multilib.
    # Since that's the default, only pass --disable-multilib. For multilib,
    # also enable multiarch. Without explicit --enable-multiarch, pass-1
    # compiler is configured as multilib/no-multiarch and pass-2/final
    # are multilib/multiarch (because gcc autodetects multiarch based on
    # multiple instances of crt*.o in the install directory - which do
    # not exist in pass-1).
    if [ "${CT_MULTILIB}" != "y" ]; then
        extra_config+=("--disable-multilib")
    else
        extra_config+=("--enable-multiarch")
        if [ -n "${CT_CC_GCC_MULTILIB_LIST}" ]; then
            extra_config+=("--with-multilib-list=${CT_CC_GCC_MULTILIB_LIST}")
        fi
    fi

    CT_DoLog DEBUG "Extra config passed: '${extra_config[*]}'"

    # Clang's default bracket-depth is 256, and building GCC
    # requires somewhere between 257 and 512.
    if ${CT_BUILD}-gcc --version 2>&1 | grep clang; then
        cflags="$cflags "-fbracket-depth=512
    fi

    # Use --with-local-prefix so older gccs don't look in /usr/local (http://gcc.gnu.org/PR10532)
    CT_DoExecLog CFG                                   \
    CC_FOR_BUILD="${CT_BUILD}-gcc"                     \
    CFLAGS="${cflags}"                                 \
    CXXFLAGS="${cflags}"                               \
    LDFLAGS="${core_LDFLAGS[*]}"                       \
    CFLAGS_FOR_TARGET="${CT_TARGET_CFLAGS}"            \
    CXXFLAGS_FOR_TARGET="${CT_TARGET_CFLAGS}"          \
    LDFLAGS_FOR_TARGET="${CT_TARGET_LDFLAGS}"          \
    ${CONFIG_SHELL}                                    \
    "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/configure" \
        --build=${CT_BUILD}                            \
        --host=${host}                                 \
        --target=${CT_TARGET}                          \
        --prefix="${prefix}"                           \
        --with-local-prefix="${CT_SYSROOT_DIR}"        \
        ${CC_CORE_SYSROOT_ARG}                         \
        "${extra_config[@]}"                           \
        --enable-languages="${lang_list}"              \
        "${extra_user_config[@]}"

    if [ "${build_libgcc}" = "yes" ]; then
        # HACK: we need to override SHLIB_LC from gcc/config/t-slibgcc-elf-ver or
        # gcc/config/t-libunwind so -lc is removed from the link for
        # libgcc_s.so, as we do not have a target -lc yet.
        # This is not as ugly as it appears to be ;-) All symbols get resolved
        # during the glibc build, and we provide a proper libgcc_s.so for the
        # cross toolchain during the final gcc build.
        #
        # As we cannot modify the source tree, nor override SHLIB_LC itself
        # during configure or make, we have to edit the resultant
        # gcc/libgcc.mk itself to remove -lc from the link.
        # This causes us to have to jump through some hoops...
        #
        # To produce libgcc.mk to edit we firstly require libiberty.a,
        # so we configure then build it.
        # Next we have to configure gcc, create libgcc.mk then edit it...
        # So much easier if we just edit the source tree, but hey...
        if [ ! -f "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/gcc/BASE-VER" ]; then
            CT_DoExecLog CFG make ${JOBSFLAGS} configure-libiberty
            CT_DoExecLog ALL make ${JOBSFLAGS} -C libiberty libiberty.a
            CT_DoExecLog CFG make ${JOBSFLAGS} configure-gcc configure-libcpp
            CT_DoExecLog ALL make ${JOBSFLAGS} all-libcpp
        else
            CT_DoExecLog CFG make ${JOBSFLAGS} configure-gcc configure-libcpp configure-build-libiberty
            CT_DoExecLog ALL make ${JOBSFLAGS} all-libcpp all-build-libiberty
        fi
        # HACK: gcc-4.2 uses libdecnumber to build libgcc.mk, so build it here.
        if [ -d "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/libdecnumber" ]; then
            CT_DoExecLog CFG make ${JOBSFLAGS} configure-libdecnumber
            CT_DoExecLog ALL make ${JOBSFLAGS} -C libdecnumber libdecnumber.a
        fi
        # HACK: gcc-4.8 uses libbacktrace to make libgcc.mvars, so make it here.
        if [ -d "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/libbacktrace" ]; then
            CT_DoExecLog CFG make ${JOBSFLAGS} configure-libbacktrace
            CT_DoExecLog ALL make ${JOBSFLAGS} -C libbacktrace
        fi

        libgcc_rule="libgcc.mvars"
        core_targets=( gcc target-libgcc )

        # On bare metal and canadian build the host-compiler is used when
        # actually the build-system compiler is required. Choose the correct
        # compilers for canadian build and use the defaults on other
        # configurations.
        if [ "${CT_BARE_METAL},${CT_CANADIAN}" = "y,y" ]; then
            repair_cc="CC_FOR_BUILD=${CT_BUILD}-gcc \
                       CXX_FOR_BUILD=${CT_BUILD}-g++ \
                       GCC_FOR_TARGET=${CT_TARGET}-${CT_CC}"
        else
            repair_cc=""
        fi

        CT_DoExecLog ALL make ${JOBSFLAGS} -C gcc ${libgcc_rule} \
                              ${repair_cc}
        sed_r -i -e 's@-lc@@g' gcc/${libgcc_rule}
    else # build_libgcc
        core_targets=( gcc )
    fi   # ! build libgcc
    if [    "${build_libstdcxx}" = "yes"    \
         -a "${CT_CC_LANG_CXX}"  = "y"      \
       ]; then
        core_targets+=( target-libstdc++-v3 )
    fi

    if [    "${build_libgfortran}" = "yes"    \
         -a "${CT_CC_LANG_FORTRAN}"  = "y"    \
       ]; then
        core_targets+=( target-libgfortran )
    fi

    core_targets_all="${core_targets[@]/#/all-}"
    core_targets_install="${core_targets[@]/#/install-}"

    case "${build_step}" in
        gcc_build|gcc_host)
            if [ "${CT_CC_GCC_TARGET_FINAL}" = "y" ]; then
                core_targets_all=all
                core_targets_install=install
            fi
            ;;
    esac

    CT_DoLog EXTRA "Building ${log_txt}"
    CT_DoExecLog ALL make ${JOBSFLAGS} ${core_targets_all}

    # Do not pass ${JOBSFLAGS} here: recent GCC builds have been failing
    # in parallel 'make install' at random locations: libitm, libcilk,
    # always for the files that are installed more than once to the same
    # location (such as libitm.info).
    # The symptom is that the install command fails with "File exists"
    # error; running the same command manually succeeds. It looks like
    # attempts to remove the destination and re-create it, but another
    # install gets in the way.
    CT_DoLog EXTRA "Installing ${log_txt}"
    CT_DoExecLog ALL make ${core_targets_install}

    # Remove the libtool "pseudo-libraries": having them in the installed
    # tree makes the libtoolized utilities that are built next assume
    # that, for example, libsupc++ is an "accessory library", and not include
    # -lsupc++ to the link flags. That breaks ltrace, for example.
    CT_DoLog EXTRA "Housekeeping for core gcc compiler"
    CT_Pushd "${prefix}"
    find . -type f -name "*.la" -exec rm {} \; |CT_DoLog ALL
    CT_Popd

    if [ "${build_manuals}" = "yes" ]; then
        CT_DoLog EXTRA "Building the GCC manuals"
        CT_DoExecLog ALL make pdf html
        CT_DoLog EXTRA "Installing the GCC manuals"
        CT_DoExecLog ALL make install-{pdf,html}-gcc
    fi

    # Create a symlink ${CT_TARGET}-cc to ${CT_TARGET}-${CT_CC} to always be able
    # to call the C compiler with the same, somewhat canonical name.
    # check whether compiler has an extension
    file="$( ls -1 "${prefix}/bin/${CT_TARGET}-${CT_CC}."* 2>/dev/null || true )"
    [ -z "${file}" ] || ext=".${file##*.}"
    if [ -f "${prefix}/bin/${CT_TARGET}-${CT_CC}${ext}" ]; then
        CT_DoExecLog ALL ln -sfv "${CT_TARGET}-${CT_CC}${ext}" "${prefix}/bin/${CT_TARGET}-cc${ext}"
    fi

    cc_gcc_multilib_housekeeping cc="${prefix}/bin/${CT_TARGET}-${CT_CC}" \
        host="${host}"
}

#------------------------------------------------------------------------------
# Build complete gcc to run on build
do_gcc_for_build() {
    local -a build_final_opts
    local build_final_backend

    # If native or simple cross toolchain is being built, then build==host;
    # nothing to do.
    case "${CT_TOOLCHAIN_TYPE}" in
        native|cross)   return 0;;
    esac

    build_final_opts+=( "host=${CT_BUILD}" )
    build_final_opts+=( "prefix=${CT_BUILDTOOLS_PREFIX_DIR}" )
    build_final_opts+=( "complibs=${CT_BUILDTOOLS_PREFIX_DIR}" )
    build_final_opts+=( "cflags=${CT_CFLAGS_FOR_BUILD}" )
    build_final_opts+=( "ldflags=${CT_LDFLAGS_FOR_BUILD}" )
    build_final_opts+=( "lang_list=$( cc_gcc_lang_list )" )
    build_final_opts+=( "build_step=gcc_build" )
    if [ "${CT_BARE_METAL}" = "y" ]; then
        # In the tests I've done, bare-metal was not impacted by the
        # lack of such a compiler, but better safe than sorry...
        build_final_opts+=( "mode=baremetal" )
        build_final_opts+=( "build_libgcc=yes" )
        build_final_opts+=( "build_libstdcxx=yes" )
        build_final_opts+=( "build_libgfortran=yes" )
        if [ "${CT_STATIC_TOOLCHAIN}" = "y" ]; then
            build_final_opts+=( "build_staticlinked=yes" )
        fi
        build_final_backend=do_gcc_core_backend
    else
        build_final_backend=do_gcc_backend
    fi

    CT_DoStep INFO "Installing final gcc compiler for build"
    CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-gcc-final-build-${CT_BUILD}"

    "${build_final_backend}" "${build_final_opts[@]}"

    CT_Popd
    CT_EndStep
}

gcc_movelibs() {
    local multi_flags multi_dir multi_os_dir multi_root multi_index multi_count
    local gcc_dir

    for arg in "$@"; do
        eval "${arg// /\\ }"
    done

    # Move only files, directories are for other multilibs. We're looking inside
    # GCC's directory structure, thus use unmangled multi_os_dir that GCC reports.
    gcc_dir="${CT_PREFIX_DIR}/${CT_TARGET}/lib/${multi_os_dir_gcc}"
    if [ ! -d "${gcc_dir}" ]; then
        # GCC didn't install anything outside of sysroot
        return
    fi
    ls "${gcc_dir}" | while read f; do
        case "${f}" in
            *.ld)
                # Linker scripts remain in GCC's directory; elf2flt insists on
                # finding them there.
                continue
                ;;
        esac
        if [ -f "${gcc_dir}/${f}" ]; then
            CT_DoExecLog ALL mkdir -p "${multi_root}/lib/${multi_os_dir}"
            CT_DoExecLog ALL mv "${gcc_dir}/${f}" "${multi_root}/lib/${multi_os_dir}/${f}"
        fi
    done
}

#------------------------------------------------------------------------------
# Build final gcc to run on host
do_gcc_for_host() {
    local -a final_opts
    local final_backend

    final_opts+=( "host=${CT_HOST}" )
    final_opts+=( "prefix=${CT_PREFIX_DIR}" )
    final_opts+=( "complibs=${CT_HOST_COMPLIBS_DIR}" )
    final_opts+=( "cflags=${CT_CFLAGS_FOR_HOST}" )
    final_opts+=( "ldflags=${CT_LDFLAGS_FOR_HOST}" )
    final_opts+=( "lang_list=$( cc_gcc_lang_list )" )
    final_opts+=( "build_step=gcc_host" )
    if [ "${CT_BUILD_MANUALS}" = "y" ]; then
        final_opts+=( "build_manuals=yes" )
    fi
    if [ "${CT_BARE_METAL}" = "y" ]; then
        final_opts+=( "mode=baremetal" )
        final_opts+=( "build_libgcc=yes" )
        final_opts+=( "build_libstdcxx=yes" )
        final_opts+=( "build_libgfortran=yes" )
        if [ "${CT_STATIC_TOOLCHAIN}" = "y" ]; then
            final_opts+=( "build_staticlinked=yes" )
        fi
        final_backend=do_gcc_core_backend
    else
        final_backend=do_gcc_backend
    fi

    CT_DoStep INFO "Installing final gcc compiler"
    CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-gcc-final"
    "${final_backend}" "${final_opts[@]}"
    CT_Popd

    # GCC installs stuff (including libgcc) into its own /lib dir,
    # outside of sysroot, breaking linking with -static-libgcc.
    # Fix up by moving the libraries into the sysroot.
    if [ "${CT_USE_SYSROOT}" = "y" ]; then
        CT_mkdir_pushd "${CT_BUILD_DIR}/build-cc-gcc-final-movelibs"
        CT_IterateMultilibs gcc_movelibs movelibs
        CT_Popd
    fi

    CT_EndStep
}

#------------------------------------------------------------------------------
# Build the final gcc
# Usage: do_gcc_backend param=value [...]
#   Parameter     : Definition                          : Type      : Default
#   host          : the host we run onto                : tuple     : (none)
#   prefix        : the runtime prefix                  : dir       : (none)
#   complibs      : the companion libraries prefix      : dir       : (none)
#   cflags        : cflags to use                       : string    : (empty)
#   ldflags       : ldflags to use                      : string    : (empty)
#   lang_list     : the list of languages to build      : string    : (empty)
#   build_manuals : whether to build manuals or not     : bool      : no
do_gcc_backend() {
    local host
    local prefix
    local complibs
    local lang_list
    local cflags
    local ldflags
    local build_manuals
    local -a host_libstdcxx_flags
    local -a extra_config
    local -a final_LDFLAGS
    local tmp
    local arg

    for arg in "$@"; do
        eval "${arg// /\\ }"
    done

    CT_DoLog EXTRA "Configuring final gcc compiler"

    # Enable selected languages
    extra_config+=("--enable-languages=${lang_list}")

    for tmp in ARCH ABI CPU TUNE FPU FLOAT; do
        eval tmp="\${CT_ARCH_WITH_${tmp}}"
        if [ -n "${tmp}" ]; then
            extra_config+=("${tmp}")
        fi
    done

    [ "${CT_SHARED_LIBS}" = "y" ] || extra_config+=("--disable-shared")
    extra_config+=("--with-pkgversion=${CT_PKGVERSION}")
    [ -n "${CT_TOOLCHAIN_BUGURL}" ] && extra_config+=("--with-bugurl=${CT_TOOLCHAIN_BUGURL}")

    case "${CT_CC_GCC_SJLJ_EXCEPTIONS}" in
        y)  extra_config+=("--enable-sjlj-exceptions");;
        m)  ;;
        "") extra_config+=("--disable-sjlj-exceptions");;
    esac
    if [ "${CT_CC_CXA_ATEXIT}" = "y" ]; then
        extra_config+=("--enable-__cxa_atexit")
    else
        extra_config+=("--disable-__cxa_atexit")
    fi

    if [ -n "${CT_CC_GCC_ENABLE_CXX_FLAGS}" ]; then
        extra_config+=("--enable-cxx-flags=${CT_CC_GCC_ENABLE_CXX_FLAGS}")
    fi

    if [ "${CT_THREADS}" = "none" ]; then
        extra_config+=(--disable-libatomic)
    fi
    if [ "${CT_CC_GCC_LIBMUDFLAP}" = "y" ]; then
        extra_config+=(--enable-libmudflap)
    else
        extra_config+=(--disable-libmudflap)
    fi
    if [ "${CT_CC_GCC_LIBGOMP}" = "y" ]; then
        extra_config+=(--enable-libgomp)
    else
        extra_config+=(--disable-libgomp)
    fi
    if [ "${CT_CC_GCC_LIBSSP}" = "y" ]; then
        extra_config+=(--enable-libssp)
    else
        extra_config+=(--disable-libssp)
    fi
    if [ "${CT_CC_GCC_LIBQUADMATH}" = "y" ]; then
        extra_config+=(--enable-libquadmath)
        extra_config+=(--enable-libquadmath-support)
    else
        extra_config+=(--disable-libquadmath)
        extra_config+=(--disable-libquadmath-support)
    fi

    if [ "${CT_CC_GCC_LIBSANITIZER}" = "y" ]; then
        extra_config+=(--enable-libsanitizer)
    else
        extra_config+=(--disable-libsanitizer)
    fi

    if [ "${CT_CC_GCC_HAS_LIBMPX}" = "y" ]; then
        if [ "${CT_CC_GCC_LIBMPX}" = "y" ]; then
            extra_config+=(--enable-libmpx)
        else
            extra_config+=(--disable-libmpx)
        fi
    fi

    final_LDFLAGS+=("${ldflags}")

    # *** WARNING ! ***
    # Keep this full if-else-if-elif-fi-fi block in sync
    # with the same block in do_gcc_core_backend, above.
    if [ "${CT_STATIC_TOOLCHAIN}" = "y" ]; then
        final_LDFLAGS+=("-static")
        host_libstdcxx_flags+=("-static-libgcc")
        host_libstdcxx_flags+=("-Wl,-Bstatic,-lstdc++")
        host_libstdcxx_flags+=("-lm")
        # Companion libraries are build static (eg !shared), so
        # the libstdc++ is not pulled automatically, although it
        # is needed. Shoe-horn it in our LDFLAGS
        # Ditto libm on some Fedora boxen
        final_LDFLAGS+=("-lstdc++")
        final_LDFLAGS+=("-lm")
    else
        if [ "${CT_CC_GCC_STATIC_LIBSTDCXX}" = "y" ]; then
            # this is from CodeSourcery arm-2010q1-202-arm-none-linux-gnueabi.src.tar.bz2
            # build script
            # INFO: if the host gcc is gcc-4.5 then presumably we could use -static-libstdc++,
            #       see http://gcc.gnu.org/ml/gcc-patches/2009-06/msg01635.html
            host_libstdcxx_flags+=("-static-libgcc")
            host_libstdcxx_flags+=("-Wl,-Bstatic,-lstdc++,-Bdynamic")
            host_libstdcxx_flags+=("-lm")
        fi
        # When companion libraries are build static (eg !shared),
        # the libstdc++ is not pulled automatically, although it
        # is needed. Shoe-horn it in our LDFLAGS
        # Ditto libm on some Fedora boxen
        final_LDFLAGS+=("-lstdc++")
        final_LDFLAGS+=("-lm")
    fi

    extra_config+=("--with-gmp=${complibs}")
    extra_config+=("--with-mpfr=${complibs}")
    extra_config+=("--with-mpc=${complibs}")
    if [ "${CT_CC_GCC_USE_GRAPHITE}" = "y" ]; then
        if [ "${CT_ISL}" = "y" ]; then
            extra_config+=("--with-isl=${complibs}")
        fi
        if [ "${CT_CLOOG}" = "y" ]; then
            extra_config+=("--with-cloog=${complibs}")
        fi
    else
        extra_config+=("--with-isl=no")
        extra_config+=("--with-cloog=no")
    fi
    if [ "${CT_CC_GCC_USE_LTO}" = "y" ]; then
        extra_config+=("--enable-lto")
    else
        extra_config+=("--disable-lto")
    fi

    if [ ${#host_libstdcxx_flags[@]} -ne 0 ]; then
        extra_config+=("--with-host-libstdcxx=${host_libstdcxx_flags[*]}")
    fi

    if [ "${CT_THREADS}" = "none" ]; then
        extra_config+=("--disable-threads")
    else
        if [ "${CT_THREADS}" = "win32" ]; then
            extra_config+=("--enable-threads=win32")
            extra_config+=("--disable-win32-registry")
        else
            extra_config+=("--enable-threads=posix")
        fi
    fi

    if [ "${CT_CC_GCC_ENABLE_TARGET_OPTSPACE}" = "y" ]; then
        extra_config+=("--enable-target-optspace")
    fi
    if [ "${CT_CC_GCC_DISABLE_PCH}" = "y" ]; then
        extra_config+=("--disable-libstdcxx-pch")
    fi

    case "${CT_CC_GCC_LDBL_128}" in
        y)  extra_config+=("--with-long-double-128");;
        m)  ;;
        "") extra_config+=("--without-long-double-128");;
    esac

    if [ "${CT_CC_GCC_BUILD_ID}" = "y" ]; then
        extra_config+=( --enable-linker-build-id )
    fi

    case "${CT_CC_GCC_LNK_HASH_STYLE}" in
        "") ;;
        *)  extra_config+=( "--with-linker-hash-style=${CT_CC_GCC_LNK_HASH_STYLE}" );;
    esac

    case "${CT_CC_GCC_DEC_FLOATS}" in
        "") ;;
        *)  extra_config+=( "--enable-decimal-float=${CT_CC_GCC_DEC_FLOATS}" );;
    esac

    if [ "${CT_CC_GCC_ENABLE_PLUGINS}" = "y" ]; then
        extra_config+=( --enable-plugin )
    else
        extra_config+=( --disable-plugin )
    fi
    if [ "${CT_CC_GCC_GOLD}" = "y" ]; then
        extra_config+=( --enable-gold )
    fi

    case "${CT_ARCH}" in
        mips)
            case "${CT_CC_GCC_mips_llsc}" in
                y)  extra_config+=( --with-llsc );;
                m)  ;;
                *)  extra_config+=( --without-llsc );;
            esac
            case "${CT_CC_GCC_mips_synci}" in
                y)  extra_config+=( --with-synci );;
                m)  ;;
                *)  extra_config+=( --without-synci );;
            esac
            if [ "${CT_CC_GCC_mips_plt}" ]; then
                extra_config+=( --with-mips-plt )
            fi
            ;; # ARCH is mips
    esac

    if [ "${CT_TOOLCHAIN_ENABLE_NLS}" = "y" ]; then
        extra_config+=("--with-libintl-prefix=${complibs}")
    else
        extra_config+=("--disable-nls")
    fi

    if [ "${CT_CC_GCC_SYSTEM_ZLIB}" = "y" ]; then
        extra_config+=("--with-system-zlib")
    fi

    # Some versions of gcc have a defective --enable-multilib.
    # Since that's the default, only pass --disable-multilib.
    if [ "${CT_MULTILIB}" != "y" ]; then
        extra_config+=("--disable-multilib")
    else
        extra_config+=("--enable-multiarch")
        if [ -n "${CT_CC_GCC_MULTILIB_LIST}" ]; then
            extra_config+=("--with-multilib-list=${CT_CC_GCC_MULTILIB_LIST}")
        fi
    fi

    CT_DoLog DEBUG "Extra config passed: '${extra_config[*]}'"

    # Clang's default bracket-depth is 256, and building GCC
    # requires somewhere between 257 and 512.
    if ${CT_BUILD}-gcc --version 2>&1 | grep clang; then
        cflags="$cflags "-fbracket-depth=512
    fi

    CT_DoExecLog CFG                                   \
    CC_FOR_BUILD="${CT_BUILD}-gcc"                     \
    CFLAGS="${cflags}"                                 \
    CXXFLAGS="${cflags}"                               \
    LDFLAGS="${final_LDFLAGS[*]}"                      \
    CFLAGS_FOR_TARGET="${CT_TARGET_CFLAGS}"            \
    CXXFLAGS_FOR_TARGET="${CT_TARGET_CFLAGS}"          \
    LDFLAGS_FOR_TARGET="${CT_TARGET_LDFLAGS}"          \
    ${CONFIG_SHELL}                                    \
    "${CT_SRC_DIR}/gcc-${CT_CC_GCC_VERSION}/configure" \
        --build=${CT_BUILD}                            \
        --host=${host}                                 \
        --target=${CT_TARGET}                          \
        --prefix="${prefix}"                           \
        ${CC_SYSROOT_ARG}                              \
        "${extra_config[@]}"                           \
        --with-local-prefix="${CT_SYSROOT_DIR}"        \
        --enable-long-long                             \
        "${CT_CC_GCC_EXTRA_CONFIG_ARRAY[@]}"

    if [ "${CT_CANADIAN}" = "y" ]; then
        CT_DoLog EXTRA "Building libiberty"
        CT_DoExecLog ALL make ${JOBSFLAGS} all-build-libiberty
    fi

    CT_DoLog EXTRA "Building final gcc compiler"
    CT_DoExecLog ALL make ${JOBSFLAGS} all

    # See the note on issues with parallel 'make install' in GCC above.
    CT_DoLog EXTRA "Installing final gcc compiler"
    if [ "${CT_STRIP_TARGET_TOOLCHAIN_EXECUTABLES}" = "y" ]; then
        CT_DoExecLog ALL make install-strip
    else
        CT_DoExecLog ALL make install
    fi

    # Remove the libtool "pseudo-libraries": having them in the installed
    # tree makes the libtoolized utilities that are built next assume
    # that, for example, libsupc++ is an "accessory library", and not include
    # -lsupc++ to the link flags. That breaks ltrace, for example.
    CT_DoLog EXTRA "Housekeeping for final gcc compiler"
    CT_Pushd "${prefix}"
    find . -type f -name "*.la" -exec rm {} \; |CT_DoLog ALL
    CT_Popd

    if [ "${build_manuals}" = "yes" ]; then
        CT_DoLog EXTRA "Building the GCC manuals"
        CT_DoExecLog ALL make pdf html
        CT_DoLog EXTRA "Installing the GCC manuals"
        CT_DoExecLog ALL make install-{pdf,html}-gcc
    fi

    # Create a symlink ${CT_TARGET}-cc to ${CT_TARGET}-${CT_CC} to always be able
    # to call the C compiler with the same, somewhat canonical name.
    # check whether compiler has an extension
    file="$( ls -1 "${CT_PREFIX_DIR}/bin/${CT_TARGET}-${CT_CC}."* 2>/dev/null || true )"
    [ -z "${file}" ] || ext=".${file##*.}"
    if [ -f "${CT_PREFIX_DIR}/bin/${CT_TARGET}-${CT_CC}${ext}" ]; then
        CT_DoExecLog ALL ln -sfv "${CT_TARGET}-${CT_CC}${ext}" "${prefix}/bin/${CT_TARGET}-cc${ext}"
    fi

    cc_gcc_multilib_housekeeping cc="${prefix}/bin/${CT_TARGET}-${CT_CC}" \
        host="${host}"
}