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hide private functions with __attribute__((visibility("hidden")))
This allows us to enforce API boundaries and potentially enables compiler optimisations. We've been always hiding non-public symbols on Windows. This commit brings that to the other platforms.
1 parent 2287d33 commit 0351a62

18 files changed

Lines changed: 1237 additions & 624 deletions

‎Configure‎

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Original file line numberDiff line numberDiff line change
@@ -391,6 +391,7 @@ d_attribute_nonnull=''
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d_attribute_noreturn=''
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d_attribute_pure=''
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d_attribute_unused=''
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d_attribute_visibility=''
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d_attribute_warn_unused_result=''
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d_printf_format_null=''
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d_backtrace=''
@@ -11337,6 +11338,34 @@ set d_attribute_always_inline
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eval $setvar
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$rm -f attrib*
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: Look for GCC-style attribute visibility
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case "$d_attribute_visibility" in
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'')
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echo " "
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echo "Checking whether your compiler can handle __attribute__((visibility)) ..." >&4
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$cat >attrib.c <<'EOCP'
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#include <stdio.h>
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__attribute__((visibility("hidden"))) int I_will_be_hidden(void);
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EOCP
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if $cc $ccflags -c attrib.c >attrib.out 2>&1 ; then
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if $compiler_warning attrib.out >/dev/null 2>&1; then
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echo "Your C compiler doesn't support __attribute__((visibility))."
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val="$undef"
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else
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echo "Your C compiler supports __attribute__((visibility))."
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val="$define"
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fi
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else
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echo "Your C compiler doesn't seem to understand __attribute__ at all."
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val="$undef"
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fi
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;;
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*) val="$d_attribute_visibility" ;;
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esac
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set d_attribute_visibility
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eval $setvar
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$rm -f attrib*
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: see if getpgrp exists
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set getpgrp d_getpgrp
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eval $inlibc
@@ -24598,6 +24627,7 @@ d_attribute_nonnull='$d_attribute_nonnull'
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d_attribute_noreturn='$d_attribute_noreturn'
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d_attribute_pure='$d_attribute_pure'
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d_attribute_unused='$d_attribute_unused'
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d_attribute_visibility='$d_attribute_visibility'
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d_attribute_warn_unused_result='$d_attribute_warn_unused_result'
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d_backtrace='$d_backtrace'
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d_bsd='$d_bsd'

‎Cross/config.sh-arm-linux‎

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Original file line numberDiff line numberDiff line change
@@ -124,6 +124,7 @@ d_attribute_nonnull='undef'
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d_attribute_noreturn='undef'
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d_attribute_pure='undef'
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d_attribute_unused='undef'
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d_attribute_visibility='undef'
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d_attribute_warn_unused_result='undef'
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d_backtrace='undef'
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d_bsd='undef'

‎Cross/config.sh-arm-linux-n770‎

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Original file line numberDiff line numberDiff line change
@@ -123,6 +123,7 @@ d_attribute_nonnull='undef'
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d_attribute_noreturn='undef'
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d_attribute_pure='undef'
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d_attribute_unused='undef'
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d_attribute_visibility='undef'
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d_attribute_warn_unused_result='undef'
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d_backtrace='undef'
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d_bsd='undef'

‎Porting/config.sh‎

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@@ -141,6 +141,7 @@ d_attribute_nonnull='define'
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d_attribute_noreturn='define'
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d_attribute_pure='define'
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d_attribute_unused='define'
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d_attribute_visibility='undef'
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d_attribute_warn_unused_result='define'
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d_backtrace='define'
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d_bsd='undef'

‎config_h.SH‎

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@@ -1495,6 +1495,10 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
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* Can we handle GCC attribute for functions that should always be
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* inlined.
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*/
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/* HASATTRIBUTE_VISIBILITY:
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* Can we handle GCC attribute for functions that should have a
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* different visibility.
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*/
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#$d_attribute_deprecated HASATTRIBUTE_DEPRECATED /**/
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#$d_attribute_format HASATTRIBUTE_FORMAT /**/
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#$d_printf_format_null PRINTF_FORMAT_NULL_OK /**/
@@ -1505,6 +1509,7 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
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#$d_attribute_unused HASATTRIBUTE_UNUSED /**/
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#$d_attribute_warn_unused_result HASATTRIBUTE_WARN_UNUSED_RESULT /**/
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#$d_attribute_always_inline HASATTRIBUTE_ALWAYS_INLINE /**/
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#$d_attribute_visibility HASATTRIBUTE_VISIBILITY /**/
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/* HAS_BACKTRACE:
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* This symbol, if defined, indicates that the backtrace() routine is

‎configure.com‎

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@@ -6124,6 +6124,7 @@ $ WC "d_attribute_nonnull='undef'"
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$ WC "d_attribute_noreturn='undef'"
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$ WC "d_attribute_pure='undef'"
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$ WC "d_attribute_unused='undef'"
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$ WC "d_attribute_visibility='undef'"
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$ WC "d_attribute_warn_unused_result='undef'"
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$ WC "d_prctl='undef'"
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$ WC "d_prctl_set_name='undef'"

‎perl.h‎

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@@ -364,6 +364,9 @@ Now a no-op.
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# if PERL_GCC_VERSION_GE(4,7,0)
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# define HASATTRIBUTE_ALWAYS_INLINE
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# endif
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# if PERL_GCC_VERSION_GE(3,3,0)
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# define HASATTRIBUTE_VISIBILITY
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# endif
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# endif
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#endif /* #ifndef PERL_MICRO */
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@@ -397,6 +400,10 @@ Now a no-op.
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# define __attribute__always_inline__ __attribute__((always_inline))
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# endif
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#endif
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#if defined(HASATTRIBUTE_VISIBILITY) && !defined(_WIN32)
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/* On Windows, instead of this, we use __declspec(dllexport) and a .def file */
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# define __attribute__visibility__(x) __attribute__((visibility(x)))
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#endif
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/* If we haven't defined the attributes yet, define them to blank. */
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#ifndef __attribute__deprecated__
@@ -426,6 +433,9 @@ Now a no-op.
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#ifndef __attribute__always_inline__
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# define __attribute__always_inline__
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#endif
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#ifndef __attribute__visibility__
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# define __attribute__visibility__(x)
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#endif
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/* Some OS warn on NULL format to printf */
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#ifdef PRINTF_FORMAT_NULL_OK

‎plan9/config_sh.sample‎

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@@ -124,6 +124,7 @@ d_attribute_nonnull='undef'
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d_attribute_noreturn='undef'
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d_attribute_pure='undef'
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d_attribute_unused='undef'
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d_attribute_visibility='undef'
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d_attribute_warn_unused_result='undef'
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d_backtrace='undef'
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d_bsd='undef'

‎pod/perldelta.pod‎

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@@ -366,6 +366,16 @@ C<PL_use_safe_putenv> has been removed and C<PERL_USE_SAFE_PUTENV> is always
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defined. This means XS modules can now call C<setenv> and C<putenv> without
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causing segfaults. [L<perl #19399|https://github.com/Perl/perl5/issues/19399>]
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=item *
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Internal C API functions are now hidden with C<__attribute__((hidden))> on the
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platforms that support it. This means they are no longer callable from XS
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modules on those platforms.
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It should be noted that those functions have always been hidden on Windows. This
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change merely brings that to the other platforms.
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[L<perl #19655|https://github.com/Perl/perl5/pull/19655>]
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=back
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=head1 Selected Bug Fixes

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