This was introduced in 2014-12 to use local binding for external symbols for -fPIE. It avoids a GOT indirection but the same optimizationis obtained with ld's R_X86_64_[REX_]GOTPCRELX optimization (albeit with slightly longer code).
One design goal of -fPIE was to avoid copy relocations. HAVE_LD_PIE_COPYRELOC has deviated from the goal. By removing HAVE_LD_PIE_COPYRELOC, the -fPIE behavior of x86-64 will match x86-32 and other targets. The design goal of protected symbols was to improve performance similar to -Bsymbolic. lld rejects copy relocations on data symbols. Latest glibc rtld reports a warning when a protected data symbol is copy relocated[1]. With the adoption of PIE most object files are -fPIE or -fPIC. -fPIE defaulting to the possibly copy relocations behavior makes protected data symbols infeasible to adopt on x86-64. [1]: https://sourceware.org/git/?p=glibc.git;a=commit;h=7374c02b683b7110b853a32496a619410364d70b ("elf: Refine direct extern access diagnostics to protected symbol") --- gcc/config.in | 6 --- gcc/config/i386/i386.cc | 16 +----- gcc/configure | 52 ------------------- gcc/configure.ac | 48 ----------------- gcc/doc/sourcebuild.texi | 3 -- .../gcc.target/i386/pie-copyrelocs-1.c | 14 ----- .../gcc.target/i386/pie-copyrelocs-2.c | 14 ----- .../gcc.target/i386/pie-copyrelocs-3.c | 14 ----- .../gcc.target/i386/pie-copyrelocs-4.c | 17 ------ gcc/testsuite/gcc.target/i386/pr32219-9.c | 1 - gcc/testsuite/lib/target-supports.exp | 47 ----------------- 11 files changed, 2 insertions(+), 230 deletions(-) delete mode 100644 gcc/testsuite/gcc.target/i386/pie-copyrelocs-1.c delete mode 100644 gcc/testsuite/gcc.target/i386/pie-copyrelocs-2.c delete mode 100644 gcc/testsuite/gcc.target/i386/pie-copyrelocs-3.c delete mode 100644 gcc/testsuite/gcc.target/i386/pie-copyrelocs-4.c diff --git a/gcc/config.in b/gcc/config.in index 16bb963b45b..ade42625deb 100644 --- a/gcc/config.in +++ b/gcc/config.in @@ -1691,12 +1691,6 @@ #endif -/* Define 0/1 if your linker supports -pie option with copy reloc. */ -#ifndef USED_FOR_TARGET -#undef HAVE_LD_PIE_COPYRELOC -#endif - - /* Define if your PowerPC linker has .gnu.attributes long double support. */ #ifndef USED_FOR_TARGET #undef HAVE_LD_PPC_GNU_ATTR_LONG_DOUBLE diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index 3d189e124e4..f9fd9650f7c 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -10790,16 +10790,7 @@ legitimate_pic_address_disp_p (rtx disp) || ix86_cmodel == CM_SMALL_PIC) return true; } - else if (!SYMBOL_REF_FAR_ADDR_P (op0) - && (SYMBOL_REF_LOCAL_P (op0) - || ((ix86_direct_extern_access - && !(SYMBOL_REF_DECL (op0) - && lookup_attribute ("nodirect_extern_access", - DECL_ATTRIBUTES (SYMBOL_REF_DECL (op0))))) - && HAVE_LD_PIE_COPYRELOC - && flag_pie - && !SYMBOL_REF_WEAK (op0) - && !SYMBOL_REF_FUNCTION_P (op0))) + else if (!SYMBOL_REF_FAR_ADDR_P (op0) && SYMBOL_REF_LOCAL_P (op0) && ix86_cmodel != CM_LARGE_PIC) return true; break; @@ -23815,10 +23806,7 @@ ix86_binds_local_p (const_tree exp) ix86_has_no_direct_extern_access = true; return default_binds_local_p_3 (exp, flag_shlib != 0, true, direct_extern_access, - (direct_extern_access - && (!flag_pic - || (TARGET_64BIT - && HAVE_LD_PIE_COPYRELOC != 0)))); + (direct_extern_access && !flag_pic)); } /* If flag_pic or ix86_direct_extern_access is false, then neither diff --git a/gcc/configure b/gcc/configure index f43dc989d02..bf8aaec6e05 100755 --- a/gcc/configure +++ b/gcc/configure @@ -30081,58 +30081,6 @@ fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_ld_pie" >&5 $as_echo "$gcc_cv_ld_pie" >&6; } -{ $as_echo "$as_me:${as_lineno-$LINENO}: checking linker PIE support with copy reloc" >&5 -$as_echo_n "checking linker PIE support with copy reloc... " >&6; } -gcc_cv_ld_pie_copyreloc=no -if test $gcc_cv_ld_pie = yes ; then - if test $in_tree_ld = yes ; then - if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 25 -o "$gcc_cv_gld_major_version" -gt 2; then - gcc_cv_ld_pie_copyreloc=yes - fi - elif test x$gcc_cv_as != x -a x$gcc_cv_ld != x ; then - # Check if linker supports -pie option with copy reloc - case "$target" in - i?86-*-linux* | x86_64-*-linux*) - cat > conftest1.s <<EOF - .globl a_glob - .data - .type a_glob, @object - .size a_glob, 4 -a_glob: - .long 2 -EOF - cat > conftest2.s <<EOF - .text - .globl main - .type main, @function -main: - movl %eax, a_glob(%rip) - .size main, .-main - .globl ptr - .section .data.rel,"aw",@progbits - .type ptr, @object -ptr: - .quad a_glob -EOF - if $gcc_cv_as --64 -o conftest1.o conftest1.s > /dev/null 2>&1 \ - && $gcc_cv_ld -shared -melf_x86_64 -o conftest1.so conftest1.o > /dev/null 2>&1 \ - && $gcc_cv_as --64 -o conftest2.o conftest2.s > /dev/null 2>&1 \ - && $gcc_cv_ld -pie -melf_x86_64 -o conftest conftest2.o conftest1.so > /dev/null 2>&1; then - gcc_cv_ld_pie_copyreloc=yes - fi - rm -f conftest conftest1.so conftest1.o conftest2.o conftest1.s conftest2.s - ;; - esac - fi -fi - -cat >>confdefs.h <<_ACEOF -#define HAVE_LD_PIE_COPYRELOC `if test x"$gcc_cv_ld_pie_copyreloc" = xyes; then echo 1; else echo 0; fi` -_ACEOF - -{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_ld_pie_copyreloc" >&5 -$as_echo "$gcc_cv_ld_pie_copyreloc" >&6; } - { $as_echo "$as_me:${as_lineno-$LINENO}: checking linker EH-compatible garbage collection of sections" >&5 $as_echo_n "checking linker EH-compatible garbage collection of sections... " >&6; } gcc_cv_ld_eh_gc_sections=no diff --git a/gcc/configure.ac b/gcc/configure.ac index 80bdd8ceef9..11b61cd159d 100644 --- a/gcc/configure.ac +++ b/gcc/configure.ac @@ -5983,54 +5983,6 @@ if test x"$gcc_cv_ld_pie" = xyes; then fi AC_MSG_RESULT($gcc_cv_ld_pie) -AC_MSG_CHECKING(linker PIE support with copy reloc) -gcc_cv_ld_pie_copyreloc=no -if test $gcc_cv_ld_pie = yes ; then - if test $in_tree_ld = yes ; then - if test "$gcc_cv_gld_major_version" -eq 2 -a "$gcc_cv_gld_minor_version" -ge 25 -o "$gcc_cv_gld_major_version" -gt 2; then - gcc_cv_ld_pie_copyreloc=yes - fi - elif test x$gcc_cv_as != x -a x$gcc_cv_ld != x ; then - # Check if linker supports -pie option with copy reloc - case "$target" in - i?86-*-linux* | x86_64-*-linux*) - cat > conftest1.s <<EOF - .globl a_glob - .data - .type a_glob, @object - .size a_glob, 4 -a_glob: - .long 2 -EOF - cat > conftest2.s <<EOF - .text - .globl main - .type main, @function -main: - movl %eax, a_glob(%rip) - .size main, .-main - .globl ptr - .section .data.rel,"aw",@progbits - .type ptr, @object -ptr: - .quad a_glob -EOF - if $gcc_cv_as --64 -o conftest1.o conftest1.s > /dev/null 2>&1 \ - && $gcc_cv_ld -shared -melf_x86_64 -o conftest1.so conftest1.o > /dev/null 2>&1 \ - && $gcc_cv_as --64 -o conftest2.o conftest2.s > /dev/null 2>&1 \ - && $gcc_cv_ld -pie -melf_x86_64 -o conftest conftest2.o conftest1.so > /dev/null 2>&1; then - gcc_cv_ld_pie_copyreloc=yes - fi - rm -f conftest conftest1.so conftest1.o conftest2.o conftest1.s conftest2.s - ;; - esac - fi -fi -AC_DEFINE_UNQUOTED(HAVE_LD_PIE_COPYRELOC, - [`if test x"$gcc_cv_ld_pie_copyreloc" = xyes; then echo 1; else echo 0; fi`], - [Define 0/1 if your linker supports -pie option with copy reloc.]) -AC_MSG_RESULT($gcc_cv_ld_pie_copyreloc) - AC_MSG_CHECKING(linker EH-compatible garbage collection of sections) gcc_cv_ld_eh_gc_sections=no if test $in_tree_ld = yes ; then diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi index 606ab85a116..2f79e542efb 100644 --- a/gcc/doc/sourcebuild.texi +++ b/gcc/doc/sourcebuild.texi @@ -2517,9 +2517,6 @@ Target supports FPU instructions. @item non_strict_align Target does not require strict alignment. -@item pie_copyreloc -The x86-64 target linker supports PIE with copy reloc. - @item rdrand Target supports x86 @code{rdrand} instruction. diff --git a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-1.c b/gcc/testsuite/gcc.target/i386/pie-copyrelocs-1.c deleted file mode 100644 index 7af851bde9b..00000000000 --- a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-1.c +++ /dev/null @@ -1,14 +0,0 @@ -/* Check that GOTPCREL isn't used to access glob_a. */ -/* { dg-do compile { target *-*-linux* } } */ -/* { dg-require-effective-target pie_copyreloc } */ -/* { dg-options "-O2 -fpie" } */ - -extern int glob_a; - -int foo () -{ - return glob_a; -} - -/* glob_a should never be accessed with a GOTPCREL. */ -/* { dg-final { scan-assembler-not "glob_a@GOTPCREL" { target { ! ia32 } } } } */ diff --git a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-2.c b/gcc/testsuite/gcc.target/i386/pie-copyrelocs-2.c deleted file mode 100644 index 19cb97e882c..00000000000 --- a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-2.c +++ /dev/null @@ -1,14 +0,0 @@ -/* Check that GOTPCREL isn't used to access glob_a. */ -/* { dg-do compile { target *-*-linux* } } */ -/* { dg-require-effective-target pie_copyreloc } */ -/* { dg-options "-O2 -fpie" } */ - -int glob_a; - -int foo () -{ - return glob_a; -} - -/* glob_a should never be accessed with a GOTPCREL. */ -/* { dg-final { scan-assembler-not "glob_a@GOTPCREL" { target { ! ia32 } } } } */ diff --git a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-3.c b/gcc/testsuite/gcc.target/i386/pie-copyrelocs-3.c deleted file mode 100644 index c2fa8968e77..00000000000 --- a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-3.c +++ /dev/null @@ -1,14 +0,0 @@ -/* Check that PLT is used to access glob_a. */ -/* { dg-do compile { target *-*-linux* } } */ -/* { dg-require-effective-target pie_copyreloc } */ -/* { dg-options "-O2 -fpie" } */ - -extern int glob_a (void); - -int foo () -{ - return glob_a (); -} - -/* glob_a should be accessed with a PLT. */ -/* { dg-final { scan-assembler "glob_a@PLT" { target { ! ia32 } } } } */ diff --git a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-4.c b/gcc/testsuite/gcc.target/i386/pie-copyrelocs-4.c deleted file mode 100644 index 413cdf381c3..00000000000 --- a/gcc/testsuite/gcc.target/i386/pie-copyrelocs-4.c +++ /dev/null @@ -1,17 +0,0 @@ -/* Check that GOTPCREL is used to access glob_a. */ -/* { dg-do compile { target *-*-linux* } } */ -/* { dg-require-effective-target pie_copyreloc } */ -/* { dg-options "-O2 -fpie" } */ - -extern int glob_a __attribute__((weak)); - -int foo () -{ - if (&glob_a != 0) - return glob_a; - else - return 0; -} - -/* weak glob_a should be accessed with a GOTPCREL. */ -/* { dg-final { scan-assembler "glob_a@GOTPCREL" { target { ! ia32 } } } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr32219-9.c b/gcc/testsuite/gcc.target/i386/pr32219-9.c index 8c218266359..4958957f5cb 100644 --- a/gcc/testsuite/gcc.target/i386/pr32219-9.c +++ b/gcc/testsuite/gcc.target/i386/pr32219-9.c @@ -1,5 +1,4 @@ /* { dg-do compile { target *-*-linux* } } */ -/* { dg-require-effective-target pie_copyreloc } */ /* { dg-options "-O2 -fpie" } */ /* Uninitialized common symbol with -fpie. */ diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp index d1f4eb7641f..93c15eae051 100644 --- a/gcc/testsuite/lib/target-supports.exp +++ b/gcc/testsuite/lib/target-supports.exp @@ -10832,53 +10832,6 @@ proc scan-ltrans-tree-dump-dem-not_required_options {} { return "-flto-partition=one" } -# Return 1 if the x86-64 target supports PIE with copy reloc, 0 -# otherwise. Cache the result. - -proc check_effective_target_pie_copyreloc { } { - global tool - global GCC_UNDER_TEST - - if { !([istarget i?86-*-*] || [istarget x86_64-*-*]) } { - return 0 - } - - # Need auto-host.h to check linker support. - if { ![file exists ../../auto-host.h ] } { - return 0 - } - - return [check_cached_effective_target pie_copyreloc { - # Set up and compile to see if linker supports PIE with copy - # reloc. Include the current process ID in the file names to - # prevent conflicts with invocations for multiple testsuites. - - set src pie[pid].c - set obj pie[pid].o - - set f [open $src "w"] - puts $f "#include \"../../auto-host.h\"" - puts $f "#if HAVE_LD_PIE_COPYRELOC == 0" - puts $f "# error Linker does not support PIE with copy reloc." - puts $f "#endif" - close $f - - verbose "check_effective_target_pie_copyreloc compiling testfile $src" 2 - set lines [${tool}_target_compile $src $obj object ""] - - file delete $src - file delete $obj - - if [string match "" $lines] then { - verbose "check_effective_target_pie_copyreloc testfile compilation passed" 2 - return 1 - } else { - verbose "check_effective_target_pie_copyreloc testfile compilation failed" 2 - return 0 - } - }] -} - # Return 1 if the x86 target supports R_386_GOT32X relocation, 0 # otherwise. Cache the result. -- 2.36.1.476.g0c4daa206d-goog
