2002-08-03 Jakub Jelinek * config/tc-i386.c (output_insn): Save frag_now and frag_now_fix () at start of insn, pass it to output_disp and output_imm. (output_disp): Added arguments. If _GLOBAL_OFFSET_TABLE_ is seen in displacement for R_386_32 reloc, use R_386_GOTPC and compute properly addend. (output_imm): Added arguments. Compute properly addend for R_386_GOTPC. (md_apply_fix3): Remove R_386_GOTPC handling. * testsuite/gas/i386/gotpc.s: New. * testsuite/gas/i386/gotpc.d: New. * testsuite/gas/i386/i386.exp: Add gotpc test. --- binutils/gas/config/tc-i386.c.jj 2002-07-18 11:35:39.000000000 +0200 +++ binutils/gas/config/tc-i386.c 2002-08-02 21:13:18.000000000 +0200 @@ -104,8 +104,10 @@ static void output_insn PARAMS ((void)); static void output_branch PARAMS ((void)); static void output_jump PARAMS ((void)); static void output_interseg_jump PARAMS ((void)); -static void output_imm PARAMS ((void)); -static void output_disp PARAMS ((void)); +static void output_imm PARAMS ((fragS *insn_start_frag, + offsetT insn_start_off)); +static void output_disp PARAMS ((fragS *insn_start_frag, + offsetT insn_start_off)); #ifndef I386COFF static void s_bss PARAMS ((int)); #endif @@ -3101,14 +3103,21 @@ output_interseg_jump () md_number_to_chars (p + size, (valueT) i.op[0].imms->X_add_number, 2); } + static void output_insn () { + fragS *insn_start_frag; + offsetT insn_start_off; + /* Tie dwarf2 debug info to the address at the start of the insn. We can't do this after the insn has been output as the current frag may have been closed off. eg. by frag_var. */ dwarf2_emit_insn (0); + insn_start_frag = frag_now; + insn_start_off = frag_now_fix (); + /* Output jumps. */ if (i.tm.opcode_modifier & Jump) output_branch (); @@ -3179,10 +3188,10 @@ output_insn () } if (i.disp_operands) - output_disp (); + output_disp (insn_start_frag, insn_start_off); if (i.imm_operands) - output_imm (); + output_imm (insn_start_frag, insn_start_off); } #ifdef DEBUG386 @@ -3194,7 +3203,9 @@ output_insn () } static void -output_disp () +output_disp (insn_start_frag, insn_start_off) + fragS *insn_start_frag; + offsetT insn_start_off; { char *p; unsigned int n; @@ -3224,6 +3235,7 @@ output_disp () } else { + RELOC_ENUM reloc_type; int size = 4; int sign = 0; int pcrel = (i.flags[n] & Operand_PCrel) != 0; @@ -3266,16 +3278,50 @@ output_disp () } p = frag_more (size); + reloc_type = reloc (size, pcrel, sign, i.reloc[n]); +#ifdef BFD_ASSEMBLER + if (reloc_type == BFD_RELOC_32 + && GOT_symbol + && GOT_symbol == i.op[n].disps->X_add_symbol + && (i.op[n].disps->X_op == O_symbol + || (i.op[n].disps->X_op == O_add + && ((symbol_get_value_expression + (i.op[n].disps->X_op_symbol)->X_op) + == O_subtract)))) + { + offsetT add; + + if (insn_start_frag == frag_now) + add = (p - frag_now->fr_literal) - insn_start_off; + else + { + fragS *fr; + + add = insn_start_frag->fr_fix - insn_start_off; + for (fr = insn_start_frag->fr_next; + fr && fr != frag_now; fr = fr->fr_next) + add += fr->fr_fix; + add += p - frag_now->fr_literal; + } + + /* We don't support dynamic linking on x86-64 yet. */ + if (flag_code == CODE_64BIT) + abort (); + reloc_type = BFD_RELOC_386_GOTPC; + i.op[n].disps->X_add_number += add; + } +#endif fix_new_exp (frag_now, p - frag_now->fr_literal, size, - i.op[n].disps, pcrel, - reloc (size, pcrel, sign, i.reloc[n])); + i.op[n].disps, pcrel, reloc_type); } } } } static void -output_imm () +output_imm (insn_start_frag, insn_start_off) + fragS *insn_start_frag; + offsetT insn_start_off; { char *p; unsigned int n; @@ -3328,6 +3374,48 @@ output_imm () p = frag_more (size); reloc_type = reloc (size, 0, sign, i.reloc[n]); #ifdef BFD_ASSEMBLER + /* This is tough to explain. We end up with this one if we + * have operands that look like + * "_GLOBAL_OFFSET_TABLE_+[.-.L284]". The goal here is to + * obtain the absolute address of the GOT, and it is strongly + * preferable from a performance point of view to avoid using + * a runtime relocation for this. The actual sequence of + * instructions often look something like: + * + * call .L66 + * .L66: + * popl %ebx + * addl $_GLOBAL_OFFSET_TABLE_+[.-.L66],%ebx + * + * The call and pop essentially return the absolute address + * of the label .L66 and store it in %ebx. The linker itself + * will ultimately change the first operand of the addl so + * that %ebx points to the GOT, but to keep things simple, the + * .o file must have this operand set so that it generates not + * the absolute address of .L66, but the absolute address of + * itself. This allows the linker itself simply treat a GOTPC + * relocation as asking for a pcrel offset to the GOT to be + * added in, and the addend of the relocation is stored in the + * operand field for the instruction itself. + * + * Our job here is to fix the operand so that it would add + * the correct offset so that %ebx would point to itself. The + * thing that is tricky is that .-.L66 will point to the + * beginning of the instruction, so we need to further modify + * the operand so that it will point to itself. There are + * other cases where you have something like: + * + * .long $_GLOBAL_OFFSET_TABLE_+[.-.L66] + * + * and here no correction would be required. Internally in + * the assembler we treat operands of this form as not being + * pcrel since the '.' is explicitly mentioned, and I wonder + * whether it would simplify matters to do it this way. Who + * knows. In earlier versions of the PIC patches, the + * pcrel_adjust field was used to store the correction, but + * since the expression is not pcrel, I felt it would be + * confusing to do it this way. */ + if (reloc_type == BFD_RELOC_32 && GOT_symbol && GOT_symbol == i.op[n].imms->X_add_symbol @@ -3337,11 +3425,26 @@ output_imm () (i.op[n].imms->X_op_symbol)->X_op) == O_subtract)))) { + offsetT add; + + if (insn_start_frag == frag_now) + add = (p - frag_now->fr_literal) - insn_start_off; + else + { + fragS *fr; + + add = insn_start_frag->fr_fix - insn_start_off; + for (fr = insn_start_frag->fr_next; + fr && fr != frag_now; fr = fr->fr_next) + add += fr->fr_fix; + add += p - frag_now->fr_literal; + } + /* We don't support dynamic linking on x86-64 yet. */ if (flag_code == CODE_64BIT) abort (); reloc_type = BFD_RELOC_386_GOTPC; - i.op[n].imms->X_add_number += 3; + i.op[n].imms->X_add_number += add; } #endif fix_new_exp (frag_now, p - frag_now->fr_literal, size, @@ -4542,48 +4645,6 @@ md_apply_fix3 (fixP, valP, seg) runtime we merely add the offset to the actual PLT entry. */ value = -4; break; - case BFD_RELOC_386_GOTPC: - -/* This is tough to explain. We end up with this one if we have - * operands that look like "_GLOBAL_OFFSET_TABLE_+[.-.L284]". The goal - * here is to obtain the absolute address of the GOT, and it is strongly - * preferable from a performance point of view to avoid using a runtime - * relocation for this. The actual sequence of instructions often look - * something like: - * - * call .L66 - * .L66: - * popl %ebx - * addl $_GLOBAL_OFFSET_TABLE_+[.-.L66],%ebx - * - * The call and pop essentially return the absolute address of - * the label .L66 and store it in %ebx. The linker itself will - * ultimately change the first operand of the addl so that %ebx points to - * the GOT, but to keep things simple, the .o file must have this operand - * set so that it generates not the absolute address of .L66, but the - * absolute address of itself. This allows the linker itself simply - * treat a GOTPC relocation as asking for a pcrel offset to the GOT to be - * added in, and the addend of the relocation is stored in the operand - * field for the instruction itself. - * - * Our job here is to fix the operand so that it would add the correct - * offset so that %ebx would point to itself. The thing that is tricky is - * that .-.L66 will point to the beginning of the instruction, so we need - * to further modify the operand so that it will point to itself. - * There are other cases where you have something like: - * - * .long $_GLOBAL_OFFSET_TABLE_+[.-.L66] - * - * and here no correction would be required. Internally in the assembler - * we treat operands of this form as not being pcrel since the '.' is - * explicitly mentioned, and I wonder whether it would simplify matters - * to do it this way. Who knows. In earlier versions of the PIC patches, - * the pcrel_adjust field was used to store the correction, but since the - * expression is not pcrel, I felt it would be confusing to do it this - * way. */ - - value -= 1; - break; case BFD_RELOC_386_GOT32: case BFD_RELOC_386_TLS_GD: case BFD_RELOC_386_TLS_LDM: --- binutils/gas/testsuite/gas/i386/gotpc.s.jj 2002-08-02 21:17:57.000000000 +0200 +++ binutils/gas/testsuite/gas/i386/gotpc.s 2002-08-03 22:55:47.000000000 +0200 @@ -0,0 +1,40 @@ + .text +test: + addl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax + addl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx + addl $_GLOBAL_OFFSET_TABLE_, %eax + addl $_GLOBAL_OFFSET_TABLE_, %ebx + leal _GLOBAL_OFFSET_TABLE+[.-test](%eax), %ebx + leal _GLOBAL_OFFSET_TABLE+[.-test](%ebx), %eax + leal _GLOBAL_OFFSET_TABLE+[.-test](%eax), %eax + leal _GLOBAL_OFFSET_TABLE+[.-test](%ebx), %ebx + subl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax + subl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx + subl $_GLOBAL_OFFSET_TABLE_, %eax + subl $_GLOBAL_OFFSET_TABLE_, %ebx + orl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax + orl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx + orl $_GLOBAL_OFFSET_TABLE_, %eax + orl $_GLOBAL_OFFSET_TABLE_, %ebx + movl $_GLOBAL_OFFSET_TABLE_+[.-test], %eax + movl $_GLOBAL_OFFSET_TABLE_+[.-test], %ebx + movl $_GLOBAL_OFFSET_TABLE_, %eax + movl $_GLOBAL_OFFSET_TABLE_, %ebx + movl $_GLOBAL_OFFSET_TABLE_+[.-test], foo + movl $_GLOBAL_OFFSET_TABLE_+[.-test], %gs:foo + gs; movl $_GLOBAL_OFFSET_TABLE_+[.-test], foo + movl $_GLOBAL_OFFSET_TABLE_+[.-test], _GLOBAL_OFFSET_TABLE_ + movl _GLOBAL_OFFSET_TABLE_+[.-test], %eax + movl _GLOBAL_OFFSET_TABLE_+[.-test], %ebx + movl %eax, _GLOBAL_OFFSET_TABLE_+[.-test] + movl %ebx, _GLOBAL_OFFSET_TABLE_+[.-test] + movl %eax, %gs:_GLOBAL_OFFSET_TABLE_+[.-test] + movl %ebx, %gs:_GLOBAL_OFFSET_TABLE_+[.-test] + gs; movl %eax, _GLOBAL_OFFSET_TABLE_+[.-test] + gs; movl %ebx, _GLOBAL_OFFSET_TABLE_+[.-test] + leal _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %eax + leal _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %ebx + movl _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %eax + movl _GLOBAL_OFFSET_TABLE_@GOTOFF(%ebx), %ebx + .long _GLOBAL_OFFSET_TABLE_+[.-test] + .long _GLOBAL_OFFSET_TABLE_@GOTOFF --- binutils/gas/testsuite/gas/i386/gotpc.d.jj 2002-08-02 21:18:43.000000000 +0200 +++ binutils/gas/testsuite/gas/i386/gotpc.d 2002-08-03 23:05:43.000000000 +0200 @@ -0,0 +1,52 @@ +#objdump: -drw +#name: i386 gotpc + +.*: +file format .* + +Disassembly of section .text: + +0+000 : + 0: 05 01 00 00 00 [ ]*add \$0x1,%eax 1: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 5: 81 c3 07 00 00 00 [ ]*add \$0x7,%ebx 7: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + b: 05 01 00 00 00 [ ]*add \$0x1,%eax c: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 10: 81 c3 02 00 00 00 [ ]*add \$0x2,%ebx 12: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 16: 8d 98 16 00 00 00 [ ]*lea 0x16\(%eax\),%ebx 18: (R_386_)?(dir)?32 _GLOBAL_OFFSET_TABLE + 1c: 8d 83 1c 00 00 00 [ ]*lea 0x1c\(%ebx\),%eax 1e: (R_386_)?(dir)?32 _GLOBAL_OFFSET_TABLE + 22: 8d 80 22 00 00 00 [ ]*lea 0x22\(%eax\),%eax 24: (R_386_)?(dir)?32 _GLOBAL_OFFSET_TABLE + 28: 8d 9b 28 00 00 00 [ ]*lea 0x28\(%ebx\),%ebx 2a: (R_386_)?(dir)?32 _GLOBAL_OFFSET_TABLE + 2e: 2d 2f 00 00 00 [ ]*sub \$0x2f,%eax 2f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 33: 81 eb 35 00 00 00 [ ]*sub \$0x35,%ebx 35: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 39: 2d 01 00 00 00 [ ]*sub \$0x1,%eax 3a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 3e: 81 eb 02 00 00 00 [ ]*sub \$0x2,%ebx 40: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 44: 0d 45 00 00 00 [ ]*or \$0x45,%eax 45: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 49: 81 cb 4b 00 00 00 [ ]*or \$0x4b,%ebx 4b: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 4f: 0d 01 00 00 00 [ ]*or \$0x1,%eax 50: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 54: 81 cb 02 00 00 00 [ ]*or \$0x2,%ebx 56: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 5a: b8 5b 00 00 00 [ ]*mov \$0x5b,%eax 5b: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 5f: bb 60 00 00 00 [ ]*mov \$0x60,%ebx 60: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 64: b8 01 00 00 00 [ ]*mov \$0x1,%eax 65: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 69: bb 01 00 00 00 [ ]*mov \$0x1,%ebx 6a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 6e: c7 05 00 00 00 00 74 00 00 00 [ ]*movl \$0x74,0x0 70: (R_386_)?(dir)?32 foo +[ ]*74: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 78: 65 c7 05 00 00 00 00 7f 00 00 00 [ ]*movl \$0x7f,%gs:0x0 7b: (R_386_)?(dir)?32 foo +[ ]*7f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 83: 65 c7 05 00 00 00 00 8a 00 00 00 [ ]*movl \$0x8a,%gs:0x0 86: (R_386_)?(dir)?32 foo +[ ]*8a: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 8e: c7 05 02 00 00 00 94 00 00 00 [ ]*movl \$0x94,0x2 90: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ +[ ]*94: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 98: a1 99 00 00 00 [ ]*mov 0x99,%eax 99: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + 9d: 8b 1d 9f 00 00 00 [ ]*mov 0x9f,%ebx 9f: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + a3: a3 a4 00 00 00 [ ]*mov %eax,0xa4 a4: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + a8: 89 1d aa 00 00 00 [ ]*mov %ebx,0xaa aa: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + ae: 65 a3 b0 00 00 00 [ ]*mov %eax,%gs:0xb0 b0: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + b4: 65 89 1d b7 00 00 00 [ ]*mov %ebx,%gs:0xb7 b7: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + bb: 65 a3 bd 00 00 00 [ ]*mov %eax,%gs:0xbd bd: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + c1: 65 89 1d c4 00 00 00 [ ]*mov %ebx,%gs:0xc4 c4: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + c8: 8d 83 00 00 00 00 [ ]*lea 0x0\(%ebx\),%eax ca: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_ + ce: 8d 9b 00 00 00 00 [ ]*lea 0x0\(%ebx\),%ebx d0: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_ + d4: 8b 83 00 00 00 00 [ ]*mov 0x0\(%ebx\),%eax d6: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_ + da: 8b 9b 00 00 00 00 [ ]*mov 0x0\(%ebx\),%ebx dc: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_ + e0: e0 00 [ ]*loopne e2 e0: (R_386_)?GOTPC _GLOBAL_OFFSET_TABLE_ + e2: 00 00 [ ]*add %al,\(%eax\) + e4: 00 00 [ ]*add %al,\(%eax\) e4: (R_386_)?GOTOFF _GLOBAL_OFFSET_TABLE_ + ... --- binutils/gas/testsuite/gas/i386/i386.exp.jj 2002-07-18 11:35:39.000000000 +0200 +++ binutils/gas/testsuite/gas/i386/i386.exp 2002-08-02 21:57:46.000000000 +0200 @@ -53,6 +53,7 @@ if [expr ([istarget "i*86-*-*"] || [ist run_dump_test "jump" run_dump_test "ssemmx2" run_dump_test "sse2" + run_dump_test "gotpc" # PIC is only supported on ELF targets. if { ([istarget "*-*-elf*"] || [istarget "*-*-linux*"] )