From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thiemo Seufer To: binutils@sources.redhat.com Subject: Re: [PATCH] Fix handling of R_MIPS_PC16 relocations Date: Thu, 06 Sep 2001 16:00:00 -0000 Message-id: <20010907005955.K2210@rembrandt.csv.ica.uni-stuttgart.de> References: <20010826233029.F13086@rembrandt.csv.ica.uni-stuttgart.de> X-SW-Source: 2001-09/msg00063.html Thiemo Seufer wrote: [snip] > /bfd/ChangeLog (elf_mips_howto_table): Fix rightshift for R_MIPS_PC16. > (mips_reloc_map): Map R_MIPS_PC16 to the BFD_RELOC_16_PCREL_S2. > (mips_elf_calculate_relocation): Fix handling of R_MIPS_PC16. > (_bfd_mips_elf_relocate_section): Likewise. This patch was wrong. The R_MIPS_PC16 relocation actually spans an offset of only 16 bit while the hardware (and internal branches without a reloc) can do 18 bit. I have no explanation why this was defined this way. The appended patch adds handling for R_MIPS_PC16 to gas and bfd. Tested for mips64-linux and mips-elf. Thiemo 2001-09-07 Thiemo Seufer /bfd/ChangeLog * elf32-mips.c (mips_elf_calculate_relocation): Fix overflow handling of R_MIPS_PC16. /gas/ChangeLog * config/tc-mips.c (append_insn): Handle BFD_RELOC_16_PCREL. (macro_build): Use BFD_RELOC_16_PCREL_S2 only for embedded PIC, BFD_RELOC_16_PCREL for the rest. (mips_ip): Likewise. (md_pcrel_from): return the right offset for the differently shifted pcrel relocs. (md_apply_fix): Handle BFD_RELOC_16_PCREL. /gas/testsuite/ChangeLog * gas/mips/beq.d: Check branches to external labels. * gas/mips/beq.s: Likewise. * gas/mips/bge.d: Likewise. * gas/mips/bge.s: Likewise. * gas/mips/bgeu.d: Likewise. * gas/mips/bgeu.s: Likewise. * gas/mips/blt.d: Likewise. * gas/mips/blt.s: Likewise. * gas/mips/bltu.d: Likewise. * gas/mips/bltu.s: Likewise. * gas/mips/elempic.d: Switch from R_MIPS_GNU_REL16_S2 to R_MIPS_PC16. * gas/mips/empic.d: Likewise. * gas/mips/empic.s: Likewise. * gas/mips/telempic.d: Likewise. * gas/mips/tempic.d: Likewise. diff -BurpNX /bigdisk/src/binutils-exclude src-orig/bfd/elf32-mips.c src/bfd/elf32-mips.c --- src-orig/bfd/elf32-mips.c Fri Aug 31 21:59:55 2001 +++ src/bfd/elf32-mips.c Thu Sep 6 21:11:29 2001 @@ -6488,8 +6488,8 @@ mips_elf_calculate_relocation (abfd, case R_MIPS_PC16: value = mips_elf_sign_extend (addend, 16) + symbol - p; - value = (bfd_vma) ((bfd_signed_vma) value / 4); overflowed_p = mips_elf_overflow_p (value, 16); + value = (bfd_vma) ((bfd_signed_vma) value / 4); break; case R_MIPS_GOT_HI16: diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/config/tc-mips.c src/gas/config/tc-mips.c --- src-orig/gas/config/tc-mips.c Fri Aug 31 22:00:08 2001 +++ src/gas/config/tc-mips.c Thu Sep 6 21:58:05 2001 @@ -1898,6 +1978,10 @@ append_insn (place, ip, address_expr, re | ((address_expr->X_add_number & 0x3fffc) >> 2)); break; + case BFD_RELOC_16_PCREL: + ip->insn_opcode |= (address_expr->X_add_number >> 2) & 0xffff; + break; + case BFD_RELOC_16_PCREL_S2: goto need_reloc; @@ -1914,7 +1998,8 @@ append_insn (place, ip, address_expr, re { fixp = fix_new_exp (frag_now, f - frag_now->fr_literal, 4, address_expr, - reloc_type == BFD_RELOC_16_PCREL_S2, + (reloc_type == BFD_RELOC_16_PCREL + || reloc_type == BFD_RELOC_16_PCREL_S2), reloc_type); if (unmatched_hi) { @@ -2699,7 +2804,10 @@ macro_build (place, counter, ep, name, f ep = NULL; } else - r = BFD_RELOC_16_PCREL_S2; + if (mips_pic == EMBEDDED_PIC) + r = BFD_RELOC_16_PCREL_S2; + else + r = BFD_RELOC_16_PCREL; continue; case 'a': @@ -7791,7 +8131,10 @@ mips_ip (str, ip) continue; case 'p': /* pc relative offset */ - offset_reloc = BFD_RELOC_16_PCREL_S2; + if (mips_pic == EMBEDDED_PIC) + offset_reloc = BFD_RELOC_16_PCREL_S2; + else + offset_reloc = BFD_RELOC_16_PCREL; my_getExpression (&offset_expr, s); s = expr_end; continue; @@ -9427,9 +9836,16 @@ md_pcrel_from (fixP) && fixP->fx_addsy != (symbolS *) NULL && ! S_IS_DEFINED (fixP->fx_addsy)) { - /* This makes a branch to an undefined symbol be a branch to the - current location. */ - return 4; + if (mips_pic == EMBEDDED_PIC) + { + /* This makes a branch to an undefined symbol be a branch to the + current location. */ + return 4; + } + else + { + return 1; + } } /* return the address of the delay slot */ @@ -9666,7 +10102,8 @@ md_apply_fix (fixP, valueP) /* BFD's REL handling, for MIPS, is _very_ weird. This gives the right results, but it can't possibly be the way things are supposed to work. */ - if (fixP->fx_r_type != BFD_RELOC_16_PCREL_S2 + if ((fixP->fx_r_type != BFD_RELOC_16_PCREL + && fixP->fx_r_type != BFD_RELOC_16_PCREL_S2) || S_GET_SEGMENT (fixP->fx_addsy) != undefined_section) value += fixP->fx_frag->fr_address + fixP->fx_where; } @@ -9812,15 +10268,18 @@ md_apply_fix (fixP, valueP) break; case BFD_RELOC_16_PCREL_S2: + if ((value & 0x3) != 0) + as_bad_where (fixP->fx_file, fixP->fx_line, + _("Branch to odd address (%lx)"), (long) value); + + /* Fall through. */ + + case BFD_RELOC_16_PCREL: /* * We need to save the bits in the instruction since fixup_segment() * might be deleting the relocation entry (i.e., a branch within * the current segment). */ - if ((value & 0x3) != 0) - as_bad_where (fixP->fx_file, fixP->fx_line, - _("Branch to odd address (%lx)"), (long) value); - if (!fixP->fx_done && value != 0) break; /* If 'value' is zero, the remaining reloc code won't actually diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/beq.d src/gas/testsuite/gas/mips/beq.d --- src-orig/gas/testsuite/gas/mips/beq.d Tue May 15 16:33:52 2001 +++ src/gas/testsuite/gas/mips/beq.d Fri Aug 31 23:01:41 2001 @@ -37,4 +37,10 @@ Disassembly of section .text: 0+2006c <[^>]*> nop 0+20070 <[^>]*> jal 0+0000 [ ]*20070: (MIPS_JMP|JMPADDR|R_MIPS_26) .text +0+20074 <[^>]*> nop +0+20078 <[^>]*> b 0+20078 +[ ]*20078: R_MIPS_PC16 external_label +0+2007c <[^>]*> nop +0+20080 <[^>]*> bal 0+20080 +[ ]*20080: R_MIPS_PC16 external_label ... diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/beq.s src/gas/testsuite/gas/mips/beq.s --- src-orig/gas/testsuite/gas/mips/beq.s Mon May 3 09:28:50 1999 +++ src/gas/testsuite/gas/mips/beq.s Fri Aug 31 23:01:41 2001 @@ -22,7 +22,9 @@ text_label: b text_label bal text_label +# Branch to an external label. + b external_label + bal external_label + # Round to a 16 byte boundary, for ease in testing multiple targets. - nop - nop nop diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bge.d src/gas/testsuite/gas/mips/bge.d --- src-orig/gas/testsuite/gas/mips/bge.d Tue May 15 16:33:52 2001 +++ src/gas/testsuite/gas/mips/bge.d Fri Aug 31 23:01:41 2001 @@ -50,4 +50,20 @@ Disassembly of section .text: 0+00a4 <[^>]*> nop 0+00a8 <[^>]*> slt at,a1,a0 0+00ac <[^>]*> bnezl at,0+0000 +0+00b0 <[^>]*> nop +0+00b4 <[^>]*> slt at,a0,a1 +0+00b8 <[^>]*> beqz at,000000b8 +[ ]*b8: R_MIPS_PC16 external_label +0+00bc <[^>]*> nop +0+00c0 <[^>]*> slt at,a1,a0 +0+00c4 <[^>]*> bnez at,000000c4 +[ ]*c4: R_MIPS_PC16 external_label +0+00c8 <[^>]*> nop +0+00cc <[^>]*> slt at,a0,a1 +0+00d0 <[^>]*> beqzl at,000000d0 +[ ]*d0: R_MIPS_PC16 external_label +0+00d4 <[^>]*> nop +0+00d8 <[^>]*> slt at,a1,a0 +0+00dc <[^>]*> bnezl at,000000dc +[ ]*dc: R_MIPS_PC16 external_label ... diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bge.s src/gas/testsuite/gas/mips/bge.s --- src-orig/gas/testsuite/gas/mips/bge.s Mon May 3 09:28:50 1999 +++ src/gas/testsuite/gas/mips/bge.s Fri Aug 31 23:01:41 2001 @@ -24,6 +24,12 @@ text_label: bgel $4,$5,text_label bgtl $4,$5,text_label +# Branch to an external label. + bge $4,$5,external_label + bgt $4,$5,external_label + bgel $4,$5,external_label + bgtl $4,$5,external_label + # Round to a 16 byte boundary, for ease in testing multiple targets. nop nop diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bgeu.d src/gas/testsuite/gas/mips/bgeu.d --- src-orig/gas/testsuite/gas/mips/bgeu.d Tue May 15 16:33:52 2001 +++ src/gas/testsuite/gas/mips/bgeu.d Fri Aug 31 23:01:41 2001 @@ -44,4 +44,20 @@ Disassembly of section .text: 0+008c <[^>]*> nop 0+0090 <[^>]*> sltu at,a1,a0 0+0094 <[^>]*> bnezl at,0+0000 +0+0098 <[^>]*> nop +0+009c <[^>]*> sltu at,a0,a1 +0+00a0 <[^>]*> beqz at,000000a0 +[ ]*a0: R_MIPS_PC16 external_label +0+00a4 <[^>]*> nop +0+00a8 <[^>]*> sltu at,a1,a0 +0+00ac <[^>]*> bnez at,000000ac +[ ]*ac: R_MIPS_PC16 external_label +0+00b0 <[^>]*> nop +0+00b4 <[^>]*> sltu at,a0,a1 +0+00b8 <[^>]*> beqzl at,000000b8 +[ ]*b8: R_MIPS_PC16 external_label +0+00bc <[^>]*> nop +0+00c0 <[^>]*> sltu at,a1,a0 +0+00c4 <[^>]*> bnezl at,000000c4 +[ ]*c4: R_MIPS_PC16 external_label ... diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bgeu.s src/gas/testsuite/gas/mips/bgeu.s --- src-orig/gas/testsuite/gas/mips/bgeu.s Mon May 3 09:28:50 1999 +++ src/gas/testsuite/gas/mips/bgeu.s Fri Aug 31 23:01:41 2001 @@ -22,6 +22,12 @@ text_label: bgeul $4,$5,text_label bgtul $4,$5,text_label +# Branch to an external label. + bgeu $4,$5,external_label + bgtu $4,$5,external_label + bgeul $4,$5,external_label + bgtul $4,$5,external_label + # Round to a 16 byte boundary, for ease in testing multiple targets. nop nop diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/blt.d src/gas/testsuite/gas/mips/blt.d --- src-orig/gas/testsuite/gas/mips/blt.d Tue May 15 16:33:52 2001 +++ src/gas/testsuite/gas/mips/blt.d Fri Aug 31 23:01:41 2001 @@ -50,4 +50,20 @@ Disassembly of section .text: 0+00a4 <[^>]*> nop 0+00a8 <[^>]*> slt at,a1,a0 0+00ac <[^>]*> beqzl at,0+0000 +0+00b0 <[^>]*> nop +0+00b4 <[^>]*> slt at,a0,a1 +0+00b8 <[^>]*> bnez at,000000b8 +[ ]*b8: R_MIPS_PC16 external_label +0+00bc <[^>]*> nop +0+00c0 <[^>]*> slt at,a1,a0 +0+00c4 <[^>]*> beqz at,000000c4 +[ ]*c4: R_MIPS_PC16 external_label +0+00c8 <[^>]*> nop +0+00cc <[^>]*> slt at,a0,a1 +0+00d0 <[^>]*> bnezl at,000000d0 +[ ]*d0: R_MIPS_PC16 external_label +0+00d4 <[^>]*> nop +0+00d8 <[^>]*> slt at,a1,a0 +0+00dc <[^>]*> beqzl at,000000dc +[ ]*dc: R_MIPS_PC16 external_label ... diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/blt.s src/gas/testsuite/gas/mips/blt.s --- src-orig/gas/testsuite/gas/mips/blt.s Mon May 3 09:28:50 1999 +++ src/gas/testsuite/gas/mips/blt.s Fri Aug 31 23:01:41 2001 @@ -24,6 +24,12 @@ text_label: bltl $4,$5,text_label blel $4,$5,text_label +# Branch to an external label. + blt $4,$5,external_label + ble $4,$5,external_label + bltl $4,$5,external_label + blel $4,$5,external_label + # Round to a 16 byte boundary, for ease in testing multiple targets. nop nop diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bltu.d src/gas/testsuite/gas/mips/bltu.d --- src-orig/gas/testsuite/gas/mips/bltu.d Tue May 15 16:33:52 2001 +++ src/gas/testsuite/gas/mips/bltu.d Fri Aug 31 23:01:41 2001 @@ -44,4 +44,20 @@ Disassembly of section .text: 0+008c <[^>]*> nop 0+0090 <[^>]*> sltu at,a1,a0 0+0094 <[^>]*> beqzl at,0+0000 +0+0098 <[^>]*> nop +0+009c <[^>]*> sltu at,a0,a1 +0+00a0 <[^>]*> bnez at,000000a0 +[ ]*a0: R_MIPS_PC16 external_label +0+00a4 <[^>]*> nop +0+00a8 <[^>]*> sltu at,a1,a0 +0+00ac <[^>]*> beqz at,000000ac +[ ]*ac: R_MIPS_PC16 external_label +0+00b0 <[^>]*> nop +0+00b4 <[^>]*> sltu at,a0,a1 +0+00b8 <[^>]*> bnezl at,000000b8 +[ ]*b8: R_MIPS_PC16 external_label +0+00bc <[^>]*> nop +0+00c0 <[^>]*> sltu at,a1,a0 +0+00c4 <[^>]*> beqzl at,000000c4 +[ ]*c4: R_MIPS_PC16 external_label ... diff -BurpNX /bigdisk/src/binutils-exclude src-orig/gas/testsuite/gas/mips/bltu.s src/gas/testsuite/gas/mips/bltu.s --- src-orig/gas/testsuite/gas/mips/bltu.s Mon May 3 09:28:50 1999 +++ src/gas/testsuite/gas/mips/bltu.s Fri Aug 31 23:01:41 2001 @@ -22,6 +22,12 @@ text_label: bltul $4,$5,text_label bleul $4,$5,text_label +# Branch to an external label. + bltu $4,$5,external_label + bleu $4,$5,external_label + bltul $4,$5,external_label + bleul $4,$5,external_label + # Round to a 16 byte boundary, for ease in testing multiple targets. nop nop