From 2a5684011edabf5804abb9e11253a9747587b284 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 15 Feb 2017 11:39:30 -0800 Subject: [PATCH] i386: Allow "lea foo@GOT, %reg" in PIC "lea foo@GOT, %reg" is OK in PIC since it only loads the GOT offset into register, which can be used later with a GOT base register to get the value in the GOT entry. bfd/ PR ld/21168 * elf32-i386.c (elf_i386_relocate_section): Allow "lea foo@GOT, %reg" in PIC. ld/ PR ld/21168 * testsuite/ld-i386/i386.exp: Run pr21168. * testsuite/ld-i386/pr21168a.c: New file. * testsuite/ld-i386/pr21168b.S: Likewise. --- bfd/ChangeLog | 6 ++++++ bfd/elf32-i386.c | 12 ++++++++---- ld/ChangeLog | 7 +++++++ ld/testsuite/ld-i386/i386.exp | 22 ++++++++++++++++++++++ ld/testsuite/ld-i386/pr21168a.c | 14 ++++++++++++++ ld/testsuite/ld-i386/pr21168b.S | 29 +++++++++++++++++++++++++++++ 6 files changed, 86 insertions(+), 4 deletions(-) create mode 100644 ld/testsuite/ld-i386/pr21168a.c create mode 100644 ld/testsuite/ld-i386/pr21168b.S diff --git a/bfd/ChangeLog b/bfd/ChangeLog index cbea9a9fcb..789915c662 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,9 @@ +2017-02-15 H.J. Lu + + PR ld/21168 + * elf32-i386.c (elf_i386_relocate_section): Allow + "lea foo@GOT, %reg" in PIC. + 2017-02-15 H.J. Lu PR ld/20244 diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c index 3bee4ca88d..e6e70d8fba 100644 --- a/bfd/elf32-i386.c +++ b/bfd/elf32-i386.c @@ -4074,7 +4074,9 @@ elf_i386_relocate_section (bfd *output_bfd, - gotplt->output_section->vma - gotplt->output_offset); - if ((*(contents + rel->r_offset - 1) & 0xc7) == 0x5) + if (rel->r_offset > 1 + && (*(contents + rel->r_offset - 1) & 0xc7) == 0x5 + && *(contents + rel->r_offset - 2) != 0x8d) { if (bfd_link_pic (info)) goto disallow_got32; @@ -4345,13 +4347,15 @@ r_386_got32: relocation = (htab->elf.sgot->output_section->vma + htab->elf.sgot->output_offset + off); - if ((*(contents + rel->r_offset - 1) & 0xc7) == 0x5) + if (rel->r_offset > 1 + && (*(contents + rel->r_offset - 1) & 0xc7) == 0x5 + && *(contents + rel->r_offset - 2) != 0x8d) { if (bfd_link_pic (info)) { /* For PIC, disallow R_386_GOT32 without a base - register since we don't know what the GOT base - is. */ + register, except for "lea foo@GOT, %reg", since + we don't know what the GOT base is. */ const char *name; disallow_got32: diff --git a/ld/ChangeLog b/ld/ChangeLog index 3f88091913..f875a8b514 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,10 @@ +2017-02-15 H.J. Lu + + PR ld/21168 + * testsuite/ld-i386/i386.exp: Run pr21168. + * testsuite/ld-i386/pr21168a.c: New file. + * testsuite/ld-i386/pr21168b.S: Likewise. + 2017-02-15 H.J. Lu PR ld/20244 diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp index 7680ff5bc9..c489227df7 100644 --- a/ld/testsuite/ld-i386/i386.exp +++ b/ld/testsuite/ld-i386/i386.exp @@ -835,6 +835,20 @@ if { [isnative] "-fPIC -O2 -g" \ { ifunc-1a.c ifunc-1b.S ifunc-1c.S ifunc-1d.S } \ ] \ + [list \ + "Build pr21168a.o" \ + "" \ + "" \ + { pr21168a.c } \ + ] \ + [list \ + "Build pr21168.so" \ + "-shared" \ + "" \ + { pr21168b.S } \ + "" \ + "pr21168.so" \ + ] \ ] run_ld_link_exec_tests [list \ @@ -856,6 +870,14 @@ if { [isnative] "ifunc-1b" \ "pass.out" \ ] \ + [list \ + "Run pr21168" \ + "tmpdir/pr21168a.o tmpdir/pr21168.so" \ + "" \ + { dummy.c } \ + "pr21168" \ + "pass.out" \ + ] \ ] } diff --git a/ld/testsuite/ld-i386/pr21168a.c b/ld/testsuite/ld-i386/pr21168a.c new file mode 100644 index 0000000000..a6c0da18ed --- /dev/null +++ b/ld/testsuite/ld-i386/pr21168a.c @@ -0,0 +1,14 @@ +#include + +int foo = 1; + +extern int *bar (void); +extern int bar_ifunc (void); + +int +main (void) +{ + if (bar () == &foo && bar_ifunc () == 0xbadbeef) + printf ("PASS\n"); + return 0; +} diff --git a/ld/testsuite/ld-i386/pr21168b.S b/ld/testsuite/ld-i386/pr21168b.S new file mode 100644 index 0000000000..a4ea5c9f7d --- /dev/null +++ b/ld/testsuite/ld-i386/pr21168b.S @@ -0,0 +1,29 @@ + .text + .globl bar + .type bar, @function +bar: + call __x86.get_pc_thunk.ax + addl $_GLOBAL_OFFSET_TABLE_, %eax + lea foo@GOT, %ecx + mov (%eax,%ecx,1), %eax + ret + .globl bar_ifunc + .type bar_ifunc, @function +bar_ifunc: + call __x86.get_pc_thunk.ax + addl $_GLOBAL_OFFSET_TABLE_, %eax + lea ifunc@GOT, %ecx + mov (%eax,%ecx,1), %eax + ret + .type ifunc, @gnu_indirect_function +ifunc: + mov $0xbadbeef, %eax + ret + .section .text.__x86.get_pc_thunk.ax,"axG",@progbits,__x86.get_pc_thunk.ax,comdat + .globl __x86.get_pc_thunk.ax + .hidden __x86.get_pc_thunk.ax + .type __x86.get_pc_thunk.ax, @function +__x86.get_pc_thunk.ax: + movl (%esp), %eax + ret + .section .note.GNU-stack,"",@progbits -- 2.34.1