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aac54dcd37
The @notoc usage only yields an advantage on ISA 3.1+ machine (power10) and for ld.bfd also when it sees pcrel relocations used on the code (generated if compiler targets ISA 3.1+). On bfd case ISA 3.1+ instruction on stubs are used iff linker also sees the new pc-relative relocations (for instance R_PPC64_D34), otherwise it generates default stubs (ppc64_elf_check_relocs:4700). This patch also help on linkers that do not implement this optimization, since building for older ISA (such as 3.0 / power9) will also trigger power10 stubs generation in the assembly code uses the NOTOC imacro. Checked on powerpc64le-linux-gnu. Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
72 lines
2.6 KiB
Plaintext
72 lines
2.6 KiB
Plaintext
# This file is generated from configure.ac by Autoconf. DO NOT EDIT!
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# Local configure fragment for sysdeps/powerpc/powerpc64.
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for support for overlapping .opd entries" >&5
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$as_echo_n "checking for support for overlapping .opd entries... " >&6; }
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if ${libc_cv_overlapping_opd+:} false; then :
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$as_echo_n "(cached) " >&6
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else
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libc_cv_overlapping_opd=no
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echo 'void foo (void) {}' > conftest.c
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if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -S conftest.c -o conftest.s 1>&5'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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ac_status=$?
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$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
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test $ac_status = 0; }; }; then
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if grep '\.TOC\.@tocbase' conftest.s > /dev/null; then
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if grep '\.TOC\.@tocbase[ ]*,[ ]*0' conftest.s > /dev/null; then
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:
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else
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libc_cv_overlapping_opd=yes
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fi
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fi
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fi
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rm -f conftest.c conftest.s
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_overlapping_opd" >&5
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$as_echo "$libc_cv_overlapping_opd" >&6; }
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if test x$libc_cv_overlapping_opd = xyes; then
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$as_echo "#define USE_PPC64_OVERLAPPING_OPD 1" >>confdefs.h
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fi
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# We check if compiler supports @notoc generation since there is no
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# gain by enabling it if it will be optimized away by the linker.
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# It also helps linkers that might not optimize it and end up
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# generating stubs with ISA 3.1 instruction even targetting older ISA.
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler supports @notoc" >&5
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$as_echo_n "checking if the compiler supports @notoc... " >&6; }
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if ${libc_cv_ppc64_notoc+:} false; then :
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$as_echo_n "(cached) " >&6
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else
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cat > conftest.c <<EOF
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int bar (void);
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int foo (void) { return bar () + 1; }
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EOF
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libc_cv_ppc64_notoc=no
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if { ac_try='${CC-cc} $libc_cv_cc_submachine $CFLAGS $CPPFLAGS -S -o conftest.s conftest.c'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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ac_status=$?
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$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
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test $ac_status = 0; }; } \
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&& { ac_try='grep -q -E 'bar@notoc' conftest.s'
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{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
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(eval $ac_try) 2>&5
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ac_status=$?
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$as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
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test $ac_status = 0; }; }
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then
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libc_cv_ppc64_notoc=yes
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fi
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rm -rf conftest.*
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ppc64_notoc" >&5
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$as_echo "$libc_cv_ppc64_notoc" >&6; }
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if test x$libc_cv_ppc64_notoc = xyes; then :
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$as_echo "#define USE_PPC64_NOTOC 1" >>confdefs.h
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fi
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