| blob | 579188397679823b790bbabee018e22b120cd8c7 |
1 /* PowerPC64-specific support for 64-bit ELF.
2 Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
3 Written by Linus Nordberg, Swox AB <info@swox.com>,
4 based on elf32-ppc.c by Ian Lance Taylor.
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 /* This file is based on the 64-bit PowerPC ELF ABI. It is also based
23 on the file elf32-ppc.c. */
33 static void ppc_howto_init
37 static void ppc64_elf_info_to_howto
39 static bfd_reloc_status_type ppc64_elf_ha_reloc
41 static bfd_reloc_status_type ppc64_elf_brtaken_reloc
43 static bfd_reloc_status_type ppc64_elf_sectoff_reloc
45 static bfd_reloc_status_type ppc64_elf_sectoff_ha_reloc
47 static bfd_reloc_status_type ppc64_elf_toc_reloc
49 static bfd_reloc_status_type ppc64_elf_toc_ha_reloc
51 static bfd_reloc_status_type ppc64_elf_toc64_reloc
53 static bfd_reloc_status_type ppc64_elf_unhandled_reloc
55 static bfd_boolean ppc64_elf_object_p
57 static bfd_boolean ppc64_elf_merge_private_bfd_data
61 /* The name of the dynamic interpreter. This is put in the .interp
62 section. */
65 /* The size in bytes of an entry in the procedure linkage table. */
66 #define PLT_ENTRY_SIZE 24
68 /* The initial size of the plt reserved for the dynamic linker. */
69 #define PLT_INITIAL_ENTRY_SIZE PLT_ENTRY_SIZE
71 /* TOC base pointers offset from start of TOC. */
72 #define TOC_BASE_OFF (0x8000)
74 /* .plt call stub instructions. */
80 /* ld %r11,xxx+16@l(%r12) */
83 /* The normal stub is this size. */
84 #define PLT_CALL_STUB_SIZE (7*4)
86 /* But sometimes the .plt entry crosses a 64k boundary, and we need
87 to adjust the high word with this insn. */
90 /* The .glink fixup call stub is the same as the .plt call stub, but
91 the first instruction restores r2, and the std is omitted. */
94 /* Always allow this much space. */
95 #define GLINK_CALL_STUB_SIZE (8*4)
97 /* Pad with this. */
98 #define NOP 0x60000000
100 /* Some other nops. */
101 #define CROR_151515 0x4def7b82
102 #define CROR_313131 0x4ffffb82
104 /* .glink entries for the first 32k functions are two instructions. */
108 /* After that, we need two instructions to load the index, followed by
109 a branch. */
113 /* Instructions to save and restore floating point regs. */
118 /* Since .opd is an array of descriptors and each entry will end up
119 with identical R_PPC64_RELATIVE relocs, there is really no need to
120 propagate .opd relocs; The dynamic linker should be taught to
121 relocate .opd without reloc entries. */
122 #ifndef NO_OPD_RELOCS
123 #define NO_OPD_RELOCS 0
124 #endif
125 \f
126 #define ONES(n) (((bfd_vma) 1 << ((n) - 1) << 1) - 1)
128 /* Relocation HOWTO's. */
132 /* This reloc does nothing. */
147 /* A standard 32 bit relocation. */
162 /* An absolute 26 bit branch; the lower two bits must be zero.
163 FIXME: we don't check that, we just clear them. */
178 /* A standard 16 bit relocation. */
193 /* A 16 bit relocation without overflow. */
208 /* Bits 16-31 of an address. */
223 /* Bits 16-31 of an address, plus 1 if the contents of the low 16
224 bits, treated as a signed number, is negative. */
239 /* An absolute 16 bit branch; the lower two bits must be zero.
240 FIXME: we don't check that, we just clear them. */
255 /* An absolute 16 bit branch, for which bit 10 should be set to
256 indicate that the branch is expected to be taken. The lower two
257 bits must be zero. */
272 /* An absolute 16 bit branch, for which bit 10 should be set to
273 indicate that the branch is not expected to be taken. The lower
274 two bits must be zero. */
289 /* A relative 26 bit branch; the lower two bits must be zero. */
304 /* A relative 16 bit branch; the lower two bits must be zero. */
319 /* A relative 16 bit branch. Bit 10 should be set to indicate that
320 the branch is expected to be taken. The lower two bits must be
321 zero. */
336 /* A relative 16 bit branch. Bit 10 should be set to indicate that
337 the branch is not expected to be taken. The lower two bits must
338 be zero. */
353 /* Like R_PPC64_ADDR16, but referring to the GOT table entry for the
354 symbol. */
369 /* Like R_PPC64_ADDR16_LO, but referring to the GOT table entry for
370 the symbol. */
385 /* Like R_PPC64_ADDR16_HI, but referring to the GOT table entry for
386 the symbol. */
401 /* Like R_PPC64_ADDR16_HA, but referring to the GOT table entry for
402 the symbol. */
417 /* This is used only by the dynamic linker. The symbol should exist
418 both in the object being run and in some shared library. The
419 dynamic linker copies the data addressed by the symbol from the
420 shared library into the object, because the object being
421 run has to have the data at some particular address. */
436 /* Like R_PPC64_ADDR64, but used when setting global offset table
437 entries. */
452 /* Created by the link editor. Marks a procedure linkage table
453 entry for a symbol. */
468 /* Used only by the dynamic linker. When the object is run, this
469 doubleword64 is set to the load address of the object, plus the
470 addend. */
485 /* Like R_PPC64_ADDR32, but may be unaligned. */
500 /* Like R_PPC64_ADDR16, but may be unaligned. */
515 /* 32-bit PC relative. */
522 /* FIXME: Verify. Was complain_overflow_bitfield. */
531 /* 32-bit relocation to the symbol's procedure linkage table. */
546 /* 32-bit PC relative relocation to the symbol's procedure linkage table.
547 FIXME: R_PPC64_PLTREL32 not supported. */
562 /* Like R_PPC64_ADDR16_LO, but referring to the PLT table entry for
563 the symbol. */
578 /* Like R_PPC64_ADDR16_HI, but referring to the PLT table entry for
579 the symbol. */
594 /* Like R_PPC64_ADDR16_HA, but referring to the PLT table entry for
595 the symbol. */
610 /* 16-bit section relative relocation. */
625 /* Like R_PPC64_SECTOFF, but no overflow warning. */
640 /* 16-bit upper half section relative relocation. */
655 /* 16-bit upper half adjusted section relative relocation. */
670 /* Like R_PPC64_REL24 without touching the two least significant
671 bits. Should have been named R_PPC64_REL30! */
686 /* Relocs in the 64-bit PowerPC ELF ABI, not in the 32-bit ABI. */
688 /* A standard 64-bit relocation. */
703 /* The bits 32-47 of an address. */
718 /* The bits 32-47 of an address, plus 1 if the contents of the low
719 16 bits, treated as a signed number, is negative. */
734 /* The bits 48-63 of an address. */
749 /* The bits 48-63 of an address, plus 1 if the contents of the low
750 16 bits, treated as a signed number, is negative. */
765 /* Like ADDR64, but may be unaligned. */
780 /* 64-bit relative relocation. */
795 /* 64-bit relocation to the symbol's procedure linkage table. */
810 /* 64-bit PC relative relocation to the symbol's procedure linkage
811 table. */
812 /* FIXME: R_PPC64_PLTREL64 not supported. */
827 /* 16 bit TOC-relative relocation. */
829 /* R_PPC64_TOC16 47 half16* S + A - .TOC. */
844 /* 16 bit TOC-relative relocation without overflow. */
846 /* R_PPC64_TOC16_LO 48 half16 #lo (S + A - .TOC.) */
861 /* 16 bit TOC-relative relocation, high 16 bits. */
863 /* R_PPC64_TOC16_HI 49 half16 #hi (S + A - .TOC.) */
878 /* 16 bit TOC-relative relocation, high 16 bits, plus 1 if the
879 contents of the low 16 bits, treated as a signed number, is
880 negative. */
882 /* R_PPC64_TOC16_HA 50 half16 #ha (S + A - .TOC.) */
897 /* 64-bit relocation; insert value of TOC base (.TOC.). */
899 /* R_PPC64_TOC 51 doubleword64 .TOC. */
914 /* Like R_PPC64_GOT16, but also informs the link editor that the
915 value to relocate may (!) refer to a PLT entry which the link
916 editor (a) may replace with the symbol value. If the link editor
917 is unable to fully resolve the symbol, it may (b) create a PLT
918 entry and store the address to the new PLT entry in the GOT.
919 This permits lazy resolution of function symbols at run time.
920 The link editor may also skip all of this and just (c) emit a
921 R_PPC64_GLOB_DAT to tie the symbol to the GOT entry. */
922 /* FIXME: R_PPC64_PLTGOT16 not implemented. */
937 /* Like R_PPC64_PLTGOT16, but without overflow. */
938 /* FIXME: R_PPC64_PLTGOT16_LO not implemented. */
953 /* Like R_PPC64_PLT_GOT16, but using bits 16-31 of the address. */
954 /* FIXME: R_PPC64_PLTGOT16_HI not implemented. */
969 /* Like R_PPC64_PLT_GOT16, but using bits 16-31 of the address, plus
970 1 if the contents of the low 16 bits, treated as a signed number,
971 is negative. */
972 /* FIXME: R_PPC64_PLTGOT16_HA not implemented. */
987 /* Like R_PPC64_ADDR16, but for instructions with a DS field. */
1002 /* Like R_PPC64_ADDR16_LO, but for instructions with a DS field. */
1017 /* Like R_PPC64_GOT16, but for instructions with a DS field. */
1032 /* Like R_PPC64_GOT16_LO, but for instructions with a DS field. */
1047 /* Like R_PPC64_PLT16_LO, but for instructions with a DS field. */
1062 /* Like R_PPC64_SECTOFF, but for instructions with a DS field. */
1077 /* Like R_PPC64_SECTOFF_LO, but for instructions with a DS field. */
1092 /* Like R_PPC64_TOC16, but for instructions with a DS field. */
1107 /* Like R_PPC64_TOC16_LO, but for instructions with a DS field. */
1122 /* Like R_PPC64_PLTGOT16, but for instructions with a DS field. */
1123 /* FIXME: R_PPC64_PLTGOT16_DS not implemented. */
1138 /* Like R_PPC64_PLTGOT16_LO, but for instructions with a DS field. */
1139 /* FIXME: R_PPC64_PLTGOT16_LO not implemented. */
1154 /* GNU extension to record C++ vtable hierarchy. */
1169 /* GNU extension to record C++ vtable member usage. */
1183 };
1185 \f
1186 /* Initialize the ppc64_elf_howto_table, so that linear accesses can
1187 be done. */
1189 static void
1191 {
1196 i++)
1197 {
1202 }
1203 }
1208 bfd_reloc_code_real_type code;
1209 {
1213 /* Initialize howto table if needed. */
1217 {
1343 }
1346 };
1348 /* Set the howto pointer for a PowerPC ELF reloc. */
1350 static void
1355 {
1358 /* Initialize howto table if needed. */
1366 }
1368 /* Handle the R_PPC_ADDR16_HA and similar relocs. */
1370 static bfd_reloc_status_type
1376 PTR data;
1380 {
1381 /* If this is a relocatable link (output_bfd test tells us), just
1382 call the generic function. Any adjustment will be done at final
1383 link time. */
1388 /* Adjust the addend for sign extension of the low 16 bits.
1389 We won't actually be using the low 16 bits, so trashing them
1390 doesn't matter. */
1393 }
1395 static bfd_reloc_status_type
1401 PTR data;
1405 {
1408 bfd_size_type octets;
1409 /* Disabled until we sort out how ld should choose 'y' vs 'at'. */
1412 /* If this is a relocatable link (output_bfd test tells us), just
1413 call the generic function. Any adjustment will be done at final
1414 link time. */
1428 {
1429 /* Set 'a' bit. This is 0b00010 in BO field for branch
1430 on CR(BI) insns (BO == 001at or 011at), and 0b01000
1431 for branch on CTR insns (BO == 1a00t or 1a01t). */
1436 else
1438 }
1439 else
1440 {
1442 bfd_vma from;
1454 /* Invert 'y' bit if not the default. */
1457 }
1460 }
1462 static bfd_reloc_status_type
1468 PTR data;
1472 {
1473 /* If this is a relocatable link (output_bfd test tells us), just
1474 call the generic function. Any adjustment will be done at final
1475 link time. */
1480 /* Subtract the symbol section base address. */
1483 }
1485 static bfd_reloc_status_type
1491 PTR data;
1495 {
1496 /* If this is a relocatable link (output_bfd test tells us), just
1497 call the generic function. Any adjustment will be done at final
1498 link time. */
1503 /* Subtract the symbol section base address. */
1506 /* Adjust the addend for sign extension of the low 16 bits. */
1509 }
1511 static bfd_reloc_status_type
1517 PTR data;
1521 {
1522 bfd_vma TOCstart;
1524 /* If this is a relocatable link (output_bfd test tells us), just
1525 call the generic function. Any adjustment will be done at final
1526 link time. */
1535 /* Subtract the TOC base address. */
1538 }
1540 static bfd_reloc_status_type
1546 PTR data;
1550 {
1551 bfd_vma TOCstart;
1553 /* If this is a relocatable link (output_bfd test tells us), just
1554 call the generic function. Any adjustment will be done at final
1555 link time. */
1564 /* Subtract the TOC base address. */
1567 /* Adjust the addend for sign extension of the low 16 bits. */
1570 }
1572 static bfd_reloc_status_type
1578 PTR data;
1582 {
1583 bfd_vma TOCstart;
1584 bfd_size_type octets;
1586 /* If this is a relocatable link (output_bfd test tells us), just
1587 call the generic function. Any adjustment will be done at final
1588 link time. */
1600 }
1602 static bfd_reloc_status_type
1608 PTR data;
1612 {
1613 /* If this is a relocatable link (output_bfd test tells us), just
1614 call the generic function. Any adjustment will be done at final
1615 link time. */
1621 {
1626 }
1628 }
1630 /* Fix bad default arch selected for a 64 bit input bfd when the
1631 default is 32 bit. */
1633 static bfd_boolean
1636 {
1638 {
1642 {
1643 /* Relies on arch after 32 bit default being 64 bit default. */
1646 }
1647 }
1649 }
1651 /* Merge backend specific data from an object file to the output
1652 object file when linking. */
1654 static bfd_boolean
1658 {
1659 /* Check if we have the same endianess. */
1663 {
1668 else
1675 }
1678 }
1679 \f
1680 /* The following functions are specific to the ELF linker, while
1681 functions above are used generally. Those named ppc64_elf_* are
1682 called by the main ELF linker code. They appear in this file more
1683 or less in the order in which they are called. eg.
1684 ppc64_elf_check_relocs is called early in the link process,
1685 ppc64_elf_finish_dynamic_sections is one of the last functions
1686 called.
1688 PowerPC64-ELF uses a similar scheme to PowerPC64-XCOFF in that
1689 functions have both a function code symbol and a function descriptor
1690 symbol. A call to foo in a relocatable object file looks like:
1692 . .text
1693 . x:
1694 . bl .foo
1695 . nop
1697 The function definition in another object file might be:
1699 . .section .opd
1700 . foo: .quad .foo
1701 . .quad .TOC.@tocbase
1702 . .quad 0
1703 .
1704 . .text
1705 . .foo: blr
1707 When the linker resolves the call during a static link, the branch
1708 unsurprisingly just goes to .foo and the .opd information is unused.
1709 If the function definition is in a shared library, things are a little
1710 different: The call goes via a plt call stub, the opd information gets
1711 copied to the plt, and the linker patches the nop.
1713 . x:
1714 . bl .foo_stub
1715 . ld 2,40(1)
1716 .
1717 .
1718 . .foo_stub:
1719 . addis 12,2,Lfoo@toc@ha # in practice, the call stub
1720 . addi 12,12,Lfoo@toc@l # is slightly optimised, but
1721 . std 2,40(1) # this is the general idea
1722 . ld 11,0(12)
1723 . ld 2,8(12)
1724 . mtctr 11
1725 . ld 11,16(12)
1726 . bctr
1727 .
1728 . .section .plt
1729 . Lfoo: reloc (R_PPC64_JMP_SLOT, foo)
1731 The "reloc ()" notation is supposed to indicate that the linker emits
1732 an R_PPC64_JMP_SLOT reloc against foo. The dynamic linker does the opd
1733 copying.
1735 What are the difficulties here? Well, firstly, the relocations
1736 examined by the linker in check_relocs are against the function code
1737 sym .foo, while the dynamic relocation in the plt is emitted against
1738 the function descriptor symbol, foo. Somewhere along the line, we need
1739 to carefully copy dynamic link information from one symbol to the other.
1740 Secondly, the generic part of the elf linker will make .foo a dynamic
1741 symbol as is normal for most other backends. We need foo dynamic
1742 instead, at least for an application final link. However, when
1743 creating a shared library containing foo, we need to have both symbols
1744 dynamic so that references to .foo are satisfied during the early
1745 stages of linking. Otherwise the linker might decide to pull in a
1746 definition from some other object, eg. a static library. */
1748 /* The linker needs to keep track of the number of relocs that it
1749 decides to copy as dynamic relocs in check_relocs for each symbol.
1750 This is so that it can later discard them if they are found to be
1751 unnecessary. We store the information in a field extending the
1752 regular ELF linker hash table. */
1754 struct ppc_dyn_relocs
1755 {
1758 /* The input section of the reloc. */
1761 /* Total number of relocs copied for the input section. */
1762 bfd_size_type count;
1764 /* Number of pc-relative relocs copied for the input section. */
1765 bfd_size_type pc_count;
1766 };
1768 /* Of those relocs that might be copied as dynamic relocs, this macro
1769 selects between relative and absolute types. */
1771 #define IS_ABSOLUTE_RELOC(RTYPE) \
1772 ((RTYPE) != R_PPC64_REL32 \
1773 && (RTYPE) != R_PPC64_REL64 \
1774 && (RTYPE) != R_PPC64_ADDR30)
1776 /* Section name for stubs is the associated section name plus this
1777 string. */
1780 /* Linker stubs.
1781 ppc_stub_long_branch:
1782 Used when a 14 bit branch (or even a 24 bit branch) can't reach its
1783 destination, but a 24 bit branch in a stub section will reach.
1784 . b dest
1786 ppc_stub_plt_branch:
1787 Similar to the above, but a 24 bit branch in the stub section won't
1788 reach its destination.
1789 . addis %r12,%r2,xxx@toc@ha
1790 . ld %r11,xxx@toc@l(%r12)
1791 . mtctr %r11
1792 . bctr
1794 ppc_stub_plt_call:
1795 Used to call a function in a shared library.
1796 . addis %r12,%r2,xxx@toc@ha
1797 . std %r2,40(%r1)
1798 . ld %r11,xxx+0@toc@l(%r12)
1799 . ld %r2,xxx+8@toc@l(%r12)
1800 . mtctr %r11
1801 . ld %r11,xxx+16@toc@l(%r12)
1802 . bctr
1803 */
1806 ppc_stub_none,
1807 ppc_stub_long_branch,
1808 ppc_stub_plt_branch,
1809 ppc_stub_plt_call
1810 };
1814 /* Base hash table entry structure. */
1817 /* The stub section. */
1820 /* Offset within stub_sec of the beginning of this stub. */
1821 bfd_vma stub_offset;
1823 /* Given the symbol's value and its section we can determine its final
1824 value when building the stubs (so the stub knows where to jump. */
1825 bfd_vma target_value;
1830 /* The symbol table entry, if any, that this was derived from. */
1833 /* Where this stub is being called from, or, in the case of combined
1834 stub sections, the first input section in the group. */
1836 };
1840 /* Base hash table entry structure. */
1843 /* Offset within .branch_lt. */
1846 /* Generation marker. */
1848 };
1850 struct ppc_link_hash_entry
1851 {
1854 /* A pointer to the most recently used stub hash entry against this
1855 symbol. */
1858 /* Track dynamic relocs copied for this symbol. */
1861 /* Link between function code and descriptor symbols. */
1864 /* Flag function code and descriptor symbols. */
1868 };
1870 /* ppc64 ELF linker hash table. */
1872 struct ppc_link_hash_table
1873 {
1876 /* The stub hash table. */
1879 /* Another hash table for plt_branch stubs. */
1882 /* Linker stub bfd. */
1885 /* Linker call-backs. */
1889 /* Array to keep track of which stub sections have been created, and
1890 information on stub grouping. */
1892 /* This is the section to which stubs in the group will be attached. */
1894 /* The stub section. */
1898 /* Assorted information used by ppc64_elf_size_stubs. */
1902 /* Short-cuts to get to dynamic linker sections. */
1914 /* Set on error. */
1917 /* Flag set when small branches are detected. Used to
1918 select suitable defaults for the stub group size. */
1921 /* Set if we detect a reference undefined weak symbol. */
1924 /* Incremented every time we size stubs. */
1927 /* Small local sym to section mapping cache. */
1929 };
1939 static void ppc64_elf_link_hash_table_free
1949 static bfd_boolean create_linkage_sections
1951 static bfd_boolean create_got_section
1953 static bfd_boolean ppc64_elf_create_dynamic_sections
1955 static void ppc64_elf_copy_indirect_symbol
1958 static bfd_boolean ppc64_elf_check_relocs
1964 static bfd_boolean ppc64_elf_gc_sweep_hook
1967 static bfd_boolean func_desc_adjust
1969 static bfd_boolean ppc64_elf_func_desc_adjust
1971 static bfd_boolean ppc64_elf_adjust_dynamic_symbol
1973 static void ppc64_elf_hide_symbol
1975 static bfd_boolean allocate_dynrelocs
1977 static bfd_boolean readonly_dynrelocs
1979 static enum elf_reloc_type_class ppc64_elf_reloc_type_class
1981 static bfd_boolean ppc64_elf_size_dynamic_sections
1988 static bfd_boolean ppc_build_one_stub
1990 static bfd_boolean ppc_size_one_stub
1992 static void group_sections
1994 static bfd_boolean ppc64_elf_relocate_section
1997 asection **));
1998 static bfd_boolean ppc64_elf_finish_dynamic_symbol
2000 Elf_Internal_Sym *));
2001 static bfd_boolean ppc64_elf_finish_dynamic_sections
2004 /* Get the ppc64 ELF linker hash table from a link_info structure. */
2006 #define ppc_hash_table(p) \
2007 ((struct ppc_link_hash_table *) ((p)->hash))
2009 #define ppc_stub_hash_lookup(table, string, create, copy) \
2010 ((struct ppc_stub_hash_entry *) \
2011 bfd_hash_lookup ((table), (string), (create), (copy)))
2013 #define ppc_branch_hash_lookup(table, string, create, copy) \
2014 ((struct ppc_branch_hash_entry *) \
2015 bfd_hash_lookup ((table), (string), (create), (copy)))
2017 /* Create an entry in the stub hash table. */
2024 {
2025 /* Allocate the structure if it has not already been allocated by a
2026 subclass. */
2028 {
2032 }
2034 /* Call the allocation method of the superclass. */
2037 {
2040 /* Initialize the local fields. */
2049 }
2052 }
2054 /* Create an entry in the branch hash table. */
2061 {
2062 /* Allocate the structure if it has not already been allocated by a
2063 subclass. */
2065 {
2069 }
2071 /* Call the allocation method of the superclass. */
2074 {
2077 /* Initialize the local fields. */
2081 }
2084 }
2086 /* Create an entry in a ppc64 ELF linker hash table. */
2093 {
2094 /* Allocate the structure if it has not already been allocated by a
2095 subclass. */
2097 {
2101 }
2103 /* Call the allocation method of the superclass. */
2106 {
2115 }
2118 }
2120 /* Create a ppc64 ELF linker hash table. */
2125 {
2134 {
2137 }
2139 /* Init the stub hash table too. */
2143 /* And the branch hash table. */
2168 }
2170 /* Free the derived linker hash table. */
2172 static void
2175 {
2181 }
2183 /* Build a name for an entry in the stub hash table. */
2191 {
2193 bfd_size_type len;
2195 /* rel->r_addend is actually 64 bit, but who uses more than +/- 2^31
2196 offsets from a sym as a branch target? In fact, we could
2197 probably assume the addend is always zero. */
2201 {
2205 {
2210 }
2211 }
2212 else
2213 {
2217 {
2223 }
2224 }
2226 }
2228 /* Look up an entry in the stub hash. Stub entries are cached because
2229 creating the stub name takes a bit of time. */
2238 {
2243 /* If this input section is part of a group of sections sharing one
2244 stub section, then use the id of the first section in the group.
2245 Stub names need to include a section id, as there may well be
2246 more than one stub used to reach say, printf, and we need to
2247 distinguish between them. */
2253 {
2255 }
2256 else
2257 {
2270 }
2273 }
2275 /* Add a new stub entry to the stub hash. Not all fields of the new
2276 stub entry are initialised. */
2283 {
2291 {
2294 {
2296 bfd_size_type len;
2311 }
2313 }
2315 /* Enter this entry into the linker stub hash table. */
2319 {
2322 stub_name);
2324 }
2330 }
2332 /* Create sections for linker generated code. */
2334 static bfd_boolean
2338 {
2340 flagword flags;
2344 /* Create .sfpr for code to save and restore fp regs. */
2353 /* Create .glink for lazy dynamic linking support. */
2360 /* Create .branch_lt for plt_branch stubs. */
2370 {
2378 }
2380 }
2382 /* Create .got and .rela.got sections in DYNOBJ, and set up
2383 shortcuts to them in our hash table. */
2385 static bfd_boolean
2389 {
2409 }
2411 /* Create the dynamic sections, and set up shortcuts. */
2413 static bfd_boolean
2417 {
2438 }
2440 /* Copy the extra info we tack onto an elf_link_hash_entry. */
2442 static void
2446 {
2453 {
2455 {
2462 /* Add reloc counts against the weak sym to the strong sym
2463 list. Merge any entries against the same section. */
2465 {
2470 {
2475 }
2478 }
2480 }
2484 }
2491 }
2493 /* Set a flag, used by ppc64_elf_gc_mark_hook, on the entry symbol and
2494 symbols undefined on the command-line. */
2496 bfd_boolean
2499 {
2505 {
2511 }
2513 }
2515 /* Look through the relocs for a section during the first phase, and
2516 calculate needed space in the global offset table, procedure
2517 linkage table, and dynamic reloc sections. */
2519 static bfd_boolean
2525 {
2541 sym_hashes_end = (sym_hashes
2548 {
2549 /* Garbage collection needs some extra help with .opd sections.
2550 We don't want to necessarily keep everything referenced by
2551 relocs in .opd, as that would keep all functions. Instead,
2552 if we reference an .opd symbol (a function descriptor), we
2553 want to keep the function code symbol's section. This is
2554 easy for global symbols, but for local syms we need to keep
2555 information about the associated function section. Later, if
2556 edit_opd deletes entries, we'll use this array to adjust
2557 local syms in .opd. */
2561 };
2562 bfd_size_type amt;
2569 }
2579 {
2587 else
2592 {
2593 /* GOT16 relocations */
2601 /* This symbol requires a global offset table entry. */
2607 {
2609 }
2610 else
2611 {
2614 /* This is a global offset table entry for a local symbol. */
2617 {
2618 bfd_size_type size;
2627 }
2629 }
2637 /* This symbol requires a procedure linkage table entry. We
2638 actually build the entry in adjust_dynamic_symbol,
2639 because this might be a case of linking PIC code without
2640 linking in any dynamic objects, in which case we don't
2641 need to generate a procedure linkage table after all. */
2643 {
2644 /* It does not make sense to have a procedure linkage
2645 table entry for a local symbol. */
2648 }
2655 /* The following relocations don't need to propagate the
2656 relocation if linking a shared object since they are
2657 section relative. */
2672 /* This relocation describes the C++ object vtable hierarchy.
2673 Reconstruct it for later use during GC. */
2679 /* This relocation describes which C++ vtable entries are actually
2680 used. Record for later use during GC. */
2690 /* Fall through. */
2696 {
2697 /* We may need a .plt entry if the function this reloc
2698 refers to is in a shared lib. */
2702 }
2710 {
2716 {
2721 }
2722 }
2728 {
2732 r_symndx);
2737 }
2738 /* Fall through. */
2762 /* Don't propagate .opd relocs. */
2766 /* If we are creating a shared library, and this is a reloc
2767 against a global symbol, or a non PC relative reloc
2768 against a local symbol, then we need to copy the reloc
2769 into the shared library. However, if we are linking with
2770 -Bsymbolic, we do not need to copy a reloc against a
2771 global symbol which is defined in an object we are
2772 including in the link (i.e., DEF_REGULAR is set). At
2773 this point we have not seen all the input files, so it is
2774 possible that DEF_REGULAR is not set now but will be set
2775 later (it is never cleared). In case of a weak definition,
2776 DEF_REGULAR may be cleared later by a strong definition in
2777 a shared library. We account for that possibility below by
2778 storing information in the relocs_copied field of the hash
2779 table entry. A similar situation occurs when creating
2780 shared libraries and symbol visibility changes render the
2781 symbol local.
2783 If on the other hand, we are creating an executable, we
2784 may need to keep relocations for symbols satisfied by a
2785 dynamic library if we manage to avoid copy relocs for the
2786 symbol. */
2801 {
2805 /* We must copy these reloc types into the output file.
2806 Create a reloc section in dynobj and make room for
2807 this reloc. */
2809 {
2813 name = (bfd_elf_string_from_elf_section
2823 {
2828 }
2833 {
2834 flagword flags;
2845 }
2847 }
2849 /* If this is a global symbol, we count the number of
2850 relocations we need for this symbol. */
2852 {
2854 }
2855 else
2856 {
2857 /* Track dynamic relocs needed for local syms too.
2858 We really need local syms available to do this
2859 easily. Oh well. */
2869 }
2873 {
2884 }
2889 }
2894 }
2895 }
2898 }
2900 /* Return the section that should be marked against GC for a given
2901 relocation. */
2910 {
2914 {
2920 {
2927 {
2932 /* Function descriptor syms cause the associated
2933 function code sym section to be marked. */
2937 /* Function entry syms return NULL if they are in .opd
2938 and are not ._start (or others undefined on the ld
2939 command line). Thus we avoid marking all function
2940 sections, as all functions are referenced in .opd. */
2953 }
2954 }
2955 }
2956 else
2957 {
2966 }
2969 }
2971 /* Update the .got, .plt. and dynamic reloc reference counts for the
2972 section being removed. */
2974 static bfd_boolean
2980 {
2994 {
3002 {
3010 {
3014 }
3015 else
3016 {
3019 }
3028 {
3032 }
3040 {
3044 }
3050 {
3060 {
3066 }
3067 }
3092 {
3102 {
3107 }
3108 }
3113 }
3114 }
3116 }
3118 /* Called via elf_link_hash_traverse to transfer dynamic linking
3119 information on function code symbol entries to their corresponding
3120 function descriptor symbol entries. */
3121 static bfd_boolean
3124 PTR inf;
3125 {
3138 /* If this is a function code symbol, transfer dynamic linking
3139 information to the function descriptor symbol. */
3150 {
3152 bfd_boolean force_local;
3154 /* Find the corresponding function descriptor symbol. Create it
3155 as undefined if necessary. */
3165 {
3183 {
3185 }
3188 }
3195 {
3200 & (ELF_LINK_HASH_REF_REGULAR
3201 | ELF_LINK_HASH_REF_DYNAMIC
3202 | ELF_LINK_HASH_REF_REGULAR_NONWEAK
3205 {
3208 }
3212 }
3214 /* Now that the info is on the function descriptor, clear the
3215 function code sym info. Any function code syms for which we
3216 don't have a definition in a regular file, we force local.
3217 This prevents a shared library from exporting syms that have
3218 been imported from another library. Function code syms that
3219 are really in the library we must leave global to prevent the
3220 linker dragging in a definition from a static library. */
3230 }
3233 }
3235 #define MIN_SAVE_FPR 14
3236 #define MAX_SAVE_FPR 31
3238 /* Called near the start of bfd_elf_size_dynamic_sections. We use
3239 this hook to a) provide some gcc support functions, and b) transfer
3240 dynamic linking information gathered so far on function code symbol
3241 entries, to their corresponding function descriptor symbol entries. */
3242 static bfd_boolean
3246 {
3258 /* We don't have any relocs. */
3261 /* First provide any missing ._savef* and ._restf* functions. */
3264 {
3270 {
3279 }
3280 }
3284 {
3290 {
3300 }
3301 }
3309 {
3311 {
3314 }
3317 }
3325 {
3330 }
3332 {
3335 }
3338 {
3343 }
3346 {
3348 }
3351 }
3353 /* Adjust a symbol defined by a dynamic object and referenced by a
3354 regular object. The current definition is in some section of the
3355 dynamic object, but we're not including those sections. We have to
3356 change the definition to something the rest of the link can
3357 understand. */
3359 static bfd_boolean
3363 {
3372 /* Deal with function syms. */
3375 {
3376 /* Clear procedure linkage table information for any symbol that
3377 won't need a .plt entry. */
3384 {
3387 }
3389 }
3390 else
3393 /* If this is a weak symbol, and there is a real definition, the
3394 processor independent code will have arranged for us to see the
3395 real definition first, and we can just use the same value. */
3397 {
3403 }
3405 /* This is a reference to a symbol defined by a dynamic object which
3406 is not a function. */
3408 /* If we are creating a shared library, we must presume that the
3409 only references to the symbol are via the global offset table.
3410 For such cases we need not do anything here; the relocations will
3411 be handled correctly by relocate_section. */
3415 /* If there are no references to this symbol that do not use the
3416 GOT, we don't need to generate a copy reloc. */
3422 {
3426 }
3428 /* If we didn't find any dynamic relocs in read-only sections, then
3429 we'll be keeping the dynamic relocs and avoiding the copy reloc. */
3431 {
3434 }
3436 /* We must allocate the symbol in our .dynbss section, which will
3437 become part of the .bss section of the executable. There will be
3438 an entry for this symbol in the .dynsym section. The dynamic
3439 object will contain position independent code, so all references
3440 from the dynamic object to this symbol will go through the global
3441 offset table. The dynamic linker will use the .dynsym entry to
3442 determine the address it must put in the global offset table, so
3443 both the dynamic object and the regular object will refer to the
3444 same memory location for the variable. */
3446 /* We must generate a R_PPC_COPY reloc to tell the dynamic linker to
3447 copy the initial value out of the dynamic object and into the
3448 runtime process image. We need to remember the offset into the
3449 .rela.bss section we are going to use. */
3451 {
3454 }
3456 /* We need to figure out the alignment required for this symbol. I
3457 have no idea how ELF linkers handle this. */
3462 /* Apply the required alignment. */
3466 {
3469 }
3471 /* Define the symbol as being at this point in the section. */
3475 /* Increment the section size to make room for the symbol. */
3479 }
3481 /* If given a function descriptor symbol, hide both the function code
3482 sym and the descriptor. */
3483 static void
3487 bfd_boolean force_local;
3488 {
3492 {
3496 {
3501 /* We aren't supposed to use alloca in BFD because on
3502 systems which do not have alloca the version in libiberty
3503 calls xmalloc, which might cause the program to crash
3504 when it runs out of memory. This function doesn't have a
3505 return status, so there's no way to gracefully return an
3506 error. So cheat. We know that string[-1] can be safely
3507 dereferenced; It's either a string in an ELF string
3508 table, or allocated in an objalloc structure. */
3517 /* Unfortunately, if it so happens that the string we were
3518 looking for was allocated immediately before this string,
3519 then we overwrote the string terminator. That's the only
3520 reason the lookup should fail. */
3522 {
3528 }
3530 {
3533 }
3534 }
3537 }
3538 }
3540 bfd_boolean
3544 {
3551 {
3557 bfd_vma offset;
3558 bfd_size_type amt;
3560 bfd_boolean need_edit;
3569 {
3570 /* Must be a ld -r link. ie. check_relocs hasn't been
3571 called. */
3574 }
3580 /* Look through the section relocs. */
3588 /* Read the relocations. */
3595 /* First run through the relocs to check they are sane, and to
3596 determine whether we need to edit this opd section. */
3601 {
3608 /* .opd contains a regular array of 24 byte entries. We're
3609 only interested in the reloc pointing to a function entry
3610 point. */
3616 {
3622 }
3631 {
3632 /* If someone messes with .opd alignment then after a
3633 "ld -r" we might have padding in the middle of .opd.
3634 Also, there's nothing to prevent someone putting
3635 something silly in .opd with the assembler. No .opd
3636 optimization for them! */
3642 }
3649 {
3657 }
3658 else
3659 {
3661 {
3669 }
3675 }
3678 {
3685 }
3687 /* opd entries are always for functions defined in the
3688 current input bfd. If the symbol isn't defined in the
3689 input bfd, then we won't be using the function in this
3690 bfd; It must be defined in a linkonce section in another
3691 bfd, or is weak. It's also possible that we are
3692 discarding the function due to a linker script /DISCARD/,
3693 which we test for via the output_section. */
3699 }
3702 {
3705 bfd_boolean skip;
3707 /* This seems a waste of time as input .opd sections are all
3708 zeros as generated by gcc, but I suppose there's no reason
3709 this will always be so. We might start putting something in
3710 the third word of .opd entries. */
3712 {
3717 {
3721 error_free_rel:
3725 }
3728 }
3738 {
3740 {
3751 {
3759 }
3760 else
3761 {
3768 }
3773 {
3775 {
3776 /* Arrange for the function descriptor sym
3777 to be dropped. */
3784 {
3797 }
3801 }
3802 }
3803 else
3804 {
3805 /* We'll be keeping this opd entry. */
3808 {
3809 /* Redefine the function descriptor symbol
3810 to this location in the opd section.
3811 We've checked above that opd relocs are
3812 ordered. */
3819 {
3832 }
3835 }
3836 else
3837 {
3838 /* Local syms are a bit tricky. We could
3839 tweak them as they can be cached, but
3840 we'd need to look through the local syms
3841 for the function descriptor sym which we
3842 don't have at the moment. So keep an
3843 array of adjustments. */
3845 }
3850 }
3853 }
3855 /* We need to adjust any reloc offsets to point to the
3856 new opd entries. While we're at it, we may as well
3857 remove redundant relocs. */
3859 {
3864 }
3865 }
3869 /* Fudge the size too, as this is used later in
3870 elf_bfd_final_link if we are emitting relocs. */
3874 }
3880 {
3883 else
3885 }
3886 }
3889 }
3891 /* This is the condition under which ppc64_elf_finish_dynamic_symbol
3892 will be called from elflink.h. If elflink.h doesn't call our
3893 finish_dynamic_symbol routine, we'll need to do something about
3894 initializing any .plt and .got entries in ppc64_elf_relocate_section. */
3895 #define WILL_CALL_FINISH_DYNAMIC_SYMBOL(DYN, INFO, H) \
3896 ((DYN) \
3897 && ((INFO)->shared \
3898 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) \
3899 && ((H)->dynindx != -1 \
3900 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0))
3902 /* Allocate space in .plt, .got and associated reloc sections for
3903 dynamic relocs. */
3905 static bfd_boolean
3908 PTR inf;
3909 {
3928 {
3932 {
3933 /* If this is the first .plt entry, make room for the special
3934 first entry. */
3941 /* Make room for this entry. */
3944 /* Make room for the .glink code. */
3948 /* We need bigger stubs past index 32767. */
3953 /* We also need to make an entry in the .rela.plt section. */
3956 }
3957 else
3958 {
3961 }
3962 }
3963 else
3964 {
3967 }
3970 {
3971 bfd_boolean dyn;
3973 /* Make sure this symbol is output as a dynamic symbol.
3974 Undefined weak syms won't yet be marked as dynamic. */
3977 {
3980 }
3988 }
3989 else
3996 /* In the shared -Bsymbolic case, discard space allocated for
3997 dynamic pc-relative relocs against symbols which turn out to be
3998 defined in regular objects. For the normal shared case, discard
3999 space for relocs that have become local due to symbol visibility
4000 changes. */
4003 {
4007 {
4011 {
4016 else
4018 }
4019 }
4020 }
4021 else
4022 {
4023 /* For the non-shared case, discard space for relocs against
4024 symbols which turn out to need copy relocs or are not
4025 dynamic. */
4033 {
4034 /* Make sure this symbol is output as a dynamic symbol.
4035 Undefined weak syms won't yet be marked as dynamic. */
4038 {
4041 }
4043 /* If that succeeded, we know we'll be keeping all the
4044 relocs. */
4047 }
4051 keep: ;
4052 }
4054 /* Finally, allocate space. */
4056 {
4059 }
4062 }
4064 /* Find any dynamic relocs that apply to read-only sections. */
4066 static bfd_boolean
4069 PTR inf;
4070 {
4079 {
4083 {
4088 /* Not an error, just cut short the traversal. */
4090 }
4091 }
4093 }
4095 /* Set the sizes of the dynamic sections. */
4097 static bfd_boolean
4101 {
4105 bfd_boolean relocs;
4114 {
4115 /* Set the contents of the .interp section to the interpreter. */
4117 {
4123 }
4124 }
4126 /* Set up .got offsets for local syms, and space for local dynamic
4127 relocs. */
4129 {
4132 bfd_size_type locsymcount;
4140 {
4147 {
4150 {
4151 /* Input section has been discarded, either because
4152 it is a copy of a linkonce section or due to
4153 linker script /DISCARD/, so we'll be discarding
4154 the relocs too. */
4155 }
4157 {
4162 }
4163 }
4164 }
4176 {
4178 {
4183 }
4184 else
4186 }
4187 }
4189 /* Allocate global sym .plt and .got entries, and space for global
4190 sym dynamic relocs. */
4193 /* We now have determined the sizes of the various dynamic sections.
4194 Allocate memory for them. */
4197 {
4202 /* These haven't been allocated yet; don't strip. */
4207 {
4208 /* Strip this section if we don't need it; see the
4209 comment below. */
4210 }
4212 {
4214 {
4215 /* If we don't need this section, strip it from the
4216 output file. This is mostly to handle .rela.bss and
4217 .rela.plt. We must create both sections in
4218 create_dynamic_sections, because they must be created
4219 before the linker maps input sections to output
4220 sections. The linker does that before
4221 adjust_dynamic_symbol is called, and it is that
4222 function which decides whether anything needs to go
4223 into these sections. */
4224 }
4225 else
4226 {
4230 /* We use the reloc_count field as a counter if we need
4231 to copy relocs into the output file. */
4233 }
4234 }
4235 else
4236 {
4237 /* It's not one of our sections, so don't allocate space. */
4239 }
4242 {
4245 }
4247 /* .plt is in the bss section. We don't initialise it. */
4251 /* Allocate memory for the section contents. We use bfd_zalloc
4252 here in case unused entries are not reclaimed before the
4253 section's contents are written out. This should not happen,
4254 but this way if it does, we get a R_PPC64_NONE reloc instead
4255 of garbage. */
4259 }
4262 {
4263 /* Add some entries to the .dynamic section. We fill in the
4264 values later, in ppc64_elf_finish_dynamic_sections, but we
4265 must add the entries now so that we get the correct size for
4266 the .dynamic section. The DT_DEBUG entry is filled in by the
4267 dynamic linker and used by the debugger. */
4268 #define add_dynamic_entry(TAG, VAL) \
4269 bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
4272 {
4275 }
4278 {
4285 }
4288 {
4292 }
4295 {
4301 /* If any dynamic relocs apply to a read-only section,
4302 then we need a DT_TEXTREL entry. */
4308 {
4311 }
4312 }
4313 }
4314 #undef add_dynamic_entry
4317 }
4319 /* Determine the type of stub needed, if any, for a call. */
4326 bfd_vma destination;
4327 {
4329 bfd_vma location;
4330 bfd_vma branch_offset;
4331 bfd_vma max_branch_offset;
4335 {
4339 {
4342 }
4347 }
4349 /* Determine where the call point is. */
4357 /* Determine if a long branch stub is needed. */
4363 /* We need a stub. Figure out whether a long_branch or plt_branch
4364 is needed later. */
4368 }
4370 /* Build a .plt call stub. */
4378 {
4379 #define PPC_LO(v) ((v) & 0xffff)
4380 #define PPC_HI(v) (((v) >> 16) & 0xffff)
4381 #define PPC_HA(v) PPC_HI ((v) + 0x8000)
4400 }
4402 static bfd_boolean
4405 PTR in_arg;
4406 {
4416 bfd_vma off;
4419 /* Massage our args to the form they really have. */
4426 /* Make a note of the offset within the stubs for this entry. */
4433 {
4435 /* Branches are relative. This is where we are going to. */
4440 /* And this is where we are coming from. */
4456 {
4461 }
4471 {
4472 /* Create a reloc for the branch lookup table entry. */
4473 Elf_Internal_Rela rela;
4485 }
4494 {
4501 }
4512 /* Do the best we can for shared libraries built without
4513 exporting ".foo" for each "foo". This can happen when symbol
4514 versioning scripts strip all bar a subset of symbols. */
4517 {
4518 /* Point the symbol at the stub. There may be multiple stubs,
4519 we don't really care; The main thing is to make this sym
4520 defined somewhere. */
4524 }
4526 /* Now build the stub. */
4538 {
4545 }
4554 }
4558 }
4560 /* As above, but don't actually build the stub. Just bump offset so
4561 we know stub section sizes, and select plt_branch stubs where
4562 long_branch stubs won't do. */
4564 static bfd_boolean
4567 PTR in_arg;
4568 {
4571 bfd_vma off;
4574 /* Massage our args to the form they really have. */
4579 {
4589 }
4590 else
4591 {
4592 /* ppc_stub_long_branch or ppc_stub_plt_branch. */
4604 {
4611 {
4616 }
4619 {
4623 }
4626 }
4627 }
4631 }
4633 /* Set up various things so that we can make a list of input sections
4634 for each output section included in the link. Returns -1 on error,
4635 0 when no stubs will be needed, and 1 on success. */
4637 int
4641 {
4646 bfd_size_type amt;
4653 /* Find the top input section id. */
4657 {
4661 {
4664 }
4665 }
4672 /* We can't use output_bfd->section_count here to find the top output
4673 section index as some sections may have been removed, and
4674 _bfd_strip_section_from_output doesn't renumber the indices. */
4678 {
4681 }
4690 /* For sections we aren't interested in, mark their entries with a
4691 value we can check later. */
4693 do
4700 {
4703 }
4706 }
4708 /* The linker repeatedly calls this function for each input section,
4709 in the order that input sections are linked into output sections.
4710 Build lists of input sections to determine groupings between which
4711 we may insert linker stubs. */
4713 void
4717 {
4721 {
4724 {
4725 /* Steal the link_sec pointer for our list. */
4726 #define PREV_SEC(sec) (htab->stub_group[(sec)->id].link_sec)
4727 /* This happens to make the list in reverse order,
4728 which is what we want. */
4731 }
4732 }
4733 }
4735 /* See whether we can group stub sections together. Grouping stub
4736 sections may result in fewer stubs. More importantly, we need to
4737 put all .init* and .fini* stubs at the beginning of the .init or
4738 .fini output sections respectively, because glibc splits the
4739 _init and _fini functions into multiple parts. Putting a stub in
4740 the middle of a function is not a good idea. */
4742 static void
4745 bfd_size_type stub_group_size;
4746 bfd_boolean stubs_always_before_branch;
4747 {
4749 do
4750 {
4755 {
4758 bfd_size_type total;
4763 else
4770 /* OK, the size from the start of CURR to the end is less
4771 than stub_group_size and thus can be handled by one stub
4772 section. (or the tail section is itself larger than
4773 stub_group_size, in which case we may be toast.) We
4774 should really be keeping track of the total size of stubs
4775 added here, as stubs contribute to the final output
4776 section size. That's a little tricky, and this way will
4777 only break if stubs added make the total size more than
4778 2^25, ie. for the default stub_group_size, if stubs total
4779 more than 2834432 bytes, or over 100000 plt call stubs. */
4780 do
4781 {
4783 /* Set up this stub group. */
4785 }
4788 /* But wait, there's more! Input sections up to stub_group_size
4789 bytes before the stub section can be handled by it too. */
4791 {
4796 {
4800 }
4801 }
4803 }
4804 }
4807 #undef PREV_SEC
4808 }
4810 /* Determine and set the size of the stub section for a final link.
4812 The basic idea here is to examine all the relocations looking for
4813 PC-relative calls to a target that is unreachable with a "bl"
4814 instruction. */
4816 bfd_boolean
4822 bfd_signed_vma group_size;
4825 {
4826 bfd_size_type stub_group_size;
4827 bfd_boolean stubs_always_before_branch;
4830 /* Stash our params away. */
4837 else
4840 {
4841 /* Default values. */
4845 }
4850 {
4854 bfd_boolean stub_changed;
4862 {
4867 /* We'll need the symbol table in a second. */
4872 /* Walk over each section attached to the input bfd. */
4876 {
4879 /* If there aren't any relocs, then there's nothing more
4880 to do. */
4885 /* If this section is a link-once section that will be
4886 discarded, then don't create any stubs. */
4891 /* Get the relocs. */
4892 internal_relocs
4899 /* Now examine each relocation. */
4903 {
4908 bfd_vma sym_value;
4909 bfd_vma destination;
4918 {
4921 }
4923 /* Only look for stubs on branch instructions. */
4930 /* Now determine the call target, its name, value,
4931 section. */
4937 {
4938 /* It's a local symbol. */
4943 {
4944 local_syms
4947 local_syms
4953 }
4962 }
4963 else
4964 {
4965 /* It's an external symbol. */
4979 {
4986 }
4988 ;
4990 ;
4991 else
4992 {
4995 }
4996 }
4998 /* Determine what (if any) linker stub is needed. */
5000 destination);
5004 /* Support for grouping stub sections. */
5007 /* Get the name of this stub. */
5015 {
5016 /* The proper stub has already been created. */
5019 }
5023 {
5025 error_ret_free_internal:
5028 error_ret_free_local:
5034 }
5041 }
5043 /* We're done with the internal relocs, free them. */
5046 }
5050 {
5053 else
5055 }
5056 }
5061 /* OK, we've added some stubs. Find out the new size of the
5062 stub sections. */
5066 {
5069 }
5075 /* Ask the linker to do its stuff. */
5077 }
5079 /* It would be nice to strip .branch_lt from the output if the
5080 section is empty, but it's too late. If we strip sections here,
5081 the dynamic symbol table is corrupted since the section symbol
5082 for the stripped section isn't written. */
5085 }
5087 /* Called after we have determined section placement. If sections
5088 move, we'll be called again. Provide a value for TOCstart. */
5090 bfd_vma
5093 {
5095 bfd_vma TOCstart;
5097 /* The TOC consists of sections .got, .toc, .tocbss, .plt in that
5098 order. The TOC starts where the first of these sections starts. */
5107 {
5108 /* This may happen for
5109 o references to TOC base (SYM@toc / TOC[tc0]) without a
5110 .toc directive
5111 o bad linker script
5112 o --gc-sections and empty TOC sections
5114 FIXME: Warn user? */
5116 /* Look for a likely section. We probably won't even be
5117 using TOCstart. */
5135 }
5142 }
5144 /* Build all the stubs associated with the current output file.
5145 The stubs are kept in a hash table attached to the main linker
5146 hash table. This function is called via gldelf64ppc_finish. */
5148 bfd_boolean
5151 {
5154 bfd_vma plt_r2;
5160 {
5161 bfd_size_type size;
5163 /* Allocate memory to hold the linker stubs. */
5166 {
5170 }
5172 }
5175 {
5178 /* Build the .glink plt call stub. */
5186 {
5189 }
5191 /* Build the .glink lazy link call stubs. */
5194 {
5196 {
5199 }
5200 else
5201 {
5206 }
5209 indx++;
5211 }
5213 }
5216 {
5221 }
5223 /* Build the stubs as directed by the stub hash table. */
5229 {
5232 }
5236 {
5239 }
5242 }
5244 /* The RELOCATE_SECTION function is called by the ELF backend linker
5245 to handle the relocations for a section.
5247 The relocs are always passed as Rela structures; if the section
5248 actually uses Rel structures, the r_addend field will always be
5249 zero.
5251 This function is responsible for adjust the section contents as
5252 necessary, and (if using Rela relocs and generating a
5253 relocateable output file) adjusting the reloc addend as
5254 necessary.
5256 This function does not have to worry about setting the reloc
5257 address or the reloc symbol index.
5259 LOCAL_SYMS is a pointer to the swapped in local symbols.
5261 LOCAL_SECTIONS is an array giving the section in the input file
5262 corresponding to the st_shndx field of each local symbol.
5264 The global hash table entry for the global symbols can be found
5265 via elf_sym_hashes (input_bfd).
5267 When generating relocateable output, this function must handle
5268 STB_LOCAL/STT_SECTION symbols specially. The output symbol is
5269 going to be the section symbol corresponding to the output
5270 section, which means that the addend must be adjusted
5271 accordingly. */
5273 static bfd_boolean
5284 {
5291 bfd_vma TOCstart;
5293 bfd_boolean is_opd;
5294 /* Disabled until we sort out how ld should choose 'y' vs 'at'. */
5300 /* Initialize howto table if needed. */
5314 {
5316 bfd_vma offset;
5317 bfd_vma addend;
5318 bfd_reloc_status_type r;
5325 bfd_vma relocation;
5326 bfd_boolean unresolved_reloc;
5327 bfd_boolean warned;
5330 bfd_vma max_br_offset;
5331 bfd_vma from;
5346 {
5347 /* Relocation value is TOC base. Symbol is ignored. */
5349 }
5351 {
5352 /* It's a local symbol. */
5358 /* rel may have changed, update our copy of addend. */
5362 {
5368 }
5369 }
5370 else
5371 {
5372 /* It's a global symbol. */
5381 {
5384 /* Set a flag that will be cleared later if we find a
5385 relocation value for this symbol. output_section
5386 is typically NULL for symbols satisfied by a shared
5387 library. */
5389 else
5393 }
5395 ;
5400 ;
5401 else
5402 {
5410 }
5411 }
5413 /* First handle relocations that tweak non-addend part of insn. */
5416 {
5420 /* Branch taken prediction relocations. */
5424 /* Fall thru. */
5426 /* Branch not taken prediction relocations. */
5431 {
5432 /* Set 'a' bit. This is 0b00010 in BO field for branch
5433 on CR(BI) insns (BO == 001at or 011at), and 0b01000
5434 for branch on CTR insns (BO == 1a00t or 1a01t). */
5439 else
5441 }
5442 else
5443 {
5444 from = (offset
5448 /* Invert 'y' bit if not the default. */
5451 }
5457 /* A REL24 branching to a linkage function is followed by a
5458 nop. We replace the nop with a ld in order to restore
5459 the TOC base pointer. Only calls to shared objects need
5460 to alter the TOC base. These are recognized by their
5461 need for a PLT entry. */
5467 {
5471 {
5475 {
5479 }
5480 }
5483 {
5484 /* If this is a plain branch rather than a branch
5485 and link, don't require a nop. */
5489 }
5492 {
5498 }
5499 }
5505 {
5506 /* Tweak calls to undefined weak functions to point at a
5507 blr. We can thus call a weak function without first
5508 checking whether the function is defined. We have a
5509 blr at the end of .sfpr. */
5514 from = (offset
5518 /* But let's not be silly about it. If the blr isn't in
5519 reach, just go to the next instruction. */
5523 }
5525 }
5527 /* Set `addend'. */
5529 {
5544 /* GOT16 relocations. Like an ADDR16 using the symbol's
5545 address in the GOT as relocation value instead of the
5546 symbols value itself. Also, create a GOT entry for the
5547 symbol and put the symbol value there. */
5554 {
5555 /* Relocation is to the entry for this symbol in the global
5556 offset table. */
5557 bfd_vma off;
5563 {
5564 bfd_boolean dyn;
5576 {
5577 /* This is actually a static link, or it is a
5578 -Bsymbolic link and the symbol is defined
5579 locally, or the symbol was forced to be local
5580 because of a version file. We must initialize
5581 this entry in the global offset table. Since the
5582 offset must always be a multiple of 8, we use the
5583 least significant bit to record whether we have
5584 initialized it already.
5586 When doing a dynamic link, we create a .rel.got
5587 relocation entry to initialize the value. This
5588 is done in the finish_dynamic_symbol routine. */
5591 else
5592 {
5596 }
5597 }
5598 else
5600 }
5601 else
5602 {
5608 /* The offset must always be a multiple of 8. We use
5609 the least significant bit to record whether we have
5610 already processed this entry. */
5613 else
5614 {
5619 {
5620 Elf_Internal_Rela outrel;
5623 /* We need to generate a R_PPC64_RELATIVE reloc
5624 for the dynamic linker. */
5634 }
5637 }
5638 }
5645 /* TOC base (r2) is TOC start plus 0x8000. */
5647 }
5655 /* Relocation is to the entry for this symbol in the
5656 procedure linkage table. */
5658 /* Resolve a PLT reloc against a local symbol directly,
5659 without using the procedure linkage table. */
5665 {
5666 /* We didn't make a PLT entry for this symbol. This
5667 happens when statically linking PIC code, or when
5668 using -Bsymbolic. */
5670 }
5678 /* TOC16 relocs. We want the offset relative to the TOC base,
5679 which is the address of the start of the TOC plus 0x8000.
5680 The TOC consists of sections .got, .toc, .tocbss, and .plt,
5681 in this order. */
5691 /* Relocate against the beginning of the section. */
5708 /* Relocations that may need to be propagated if this is a
5709 dynamic object. */
5732 /* r_symndx will be zero only for relocs against symbols
5733 from removed linkonce sections, or sections discarded by
5734 a linker script. */
5737 /* Fall thru. */
5763 {
5764 Elf_Internal_Rela outrel;
5769 /* When generating a dynamic object, these relocations
5770 are copied into the output file to be resolved at run
5771 time. */
5791 && !is_opd
5798 else
5799 {
5800 /* This symbol is local, or marked to become local,
5801 or this is an opd section reloc which must point
5802 at a local function. */
5806 {
5808 {
5809 /* Lie about opd entries. This case occurs
5810 when building shared libraries and we
5811 reference a function in another shared
5812 lib. The same thing happens for a weak
5813 definition in an application that's
5814 overridden by a strong definition in a
5815 shared lib. (I believe this is a generic
5816 bug in binutils handling of weak syms.)
5817 In these cases we won't use the opd
5818 entry in this lib. */
5820 }
5822 }
5823 else
5824 {
5828 ;
5830 {
5833 }
5834 else
5835 {
5841 /* We are turning this relocation into one
5842 against a section symbol, so subtract out
5843 the output section's address but not the
5844 offset of the input section in the output
5845 section. */
5847 }
5850 }
5851 }
5861 /* If this reloc is against an external symbol, it will
5862 be computed at runtime, so there's no need to do
5863 anything now. */
5866 }
5873 /* We shouldn't ever see these dynamic relocs in relocatable
5874 files. */
5875 /* Fall thru */
5885 /* These ones haven't been implemented yet. */
5895 }
5897 /* Do any further special processing. */
5899 {
5909 /* It's just possible that this symbol is a weak symbol
5910 that's not actually defined anywhere. In that case,
5911 'sec' would be NULL, and we should leave the symbol
5912 alone (it will be set to zero elsewhere in the link). */
5914 /* Add 0x10000 if sign bit in 0:15 is set. */
5930 {
5938 }
5950 branch_check:
5951 /* If the branch is out of reach, then redirect the
5952 call to the local stub for this function. */
5953 from = (offset
5959 {
5960 /* Munge up the value and addend so that we call the stub
5961 rather than the procedure directly. */
5966 }
5968 }
5970 /* Dynamic relocs are not propagated for SEC_DEBUGGING sections
5971 because such sections are not SEC_ALLOC and thus ld.so will
5972 not process them. */
5976 {
5984 }
5987 input_bfd,
5988 input_section,
5989 contents,
5990 offset,
5991 relocation,
5992 addend);
5995 {
5999 {
6002 {
6003 /* Assume this is a call protected by other code that
6004 detects the symbol is undefined. If this is the case,
6005 we can safely ignore the overflow. If not, the
6006 program is hosed anyway, and a little warning isn't
6007 going to help. */
6010 }
6013 }
6014 else
6015 {
6023 }
6026 {
6033 }
6034 else
6035 {
6042 }
6043 }
6044 }
6047 }
6049 /* Finish up dynamic symbol handling. We set the contents of various
6050 dynamic sections here. */
6052 static bfd_boolean
6058 {
6067 {
6068 Elf_Internal_Rela rela;
6071 /* This symbol has an entry in the procedure linkage table. Set
6072 it up. */
6079 /* Create a JMP_SLOT reloc to inform the dynamic linker to
6080 fill in the PLT entry. */
6092 }
6095 {
6096 Elf_Internal_Rela rela;
6099 /* This symbol has an entry in the global offset table. Set it
6100 up. */
6109 /* If this is a static link, or it is a -Bsymbolic link and the
6110 symbol is defined locally or was forced to be local because
6111 of a version file, we just want to emit a RELATIVE reloc.
6112 The entry in the global offset table will already have been
6113 initialized in the relocate_section function. */
6119 {
6125 }
6126 else
6127 {
6133 }
6138 }
6141 {
6142 Elf_Internal_Rela rela;
6145 /* This symbol needs a copy reloc. Set it up. */
6161 }
6163 /* Mark some specially defined symbols as absolute. */
6168 }
6170 /* Used to decide how to sort relocs in an optimal manner for the
6171 dynamic linker, before writing them out. */
6173 static enum elf_reloc_type_class
6176 {
6181 {
6190 }
6191 }
6193 /* Finish up the dynamic sections. */
6195 static bfd_boolean
6199 {
6209 {
6218 {
6219 Elf_Internal_Dyn dyn;
6225 {
6263 /* Don't count procedure linkage table relocs in the
6264 overall reloc count. */
6272 /* We may not be using the standard ELF linker script.
6273 If .rela.plt is the first .rela section, we adjust
6274 DT_RELA to not include it. */
6282 }
6285 }
6286 }
6289 {
6290 /* Fill in the first entry in the global offset table.
6291 We use it to hold the link-time TOCbase. */
6296 /* Set .got entry size. */
6298 }
6301 {
6302 /* Set .plt entry size. */
6305 }
6308 }
6310 #define TARGET_LITTLE_SYM bfd_elf64_powerpcle_vec
6312 #define TARGET_BIG_SYM bfd_elf64_powerpc_vec
6314 #define ELF_ARCH bfd_arch_powerpc
6315 #define ELF_MACHINE_CODE EM_PPC64
6316 #define ELF_MAXPAGESIZE 0x10000
6317 #define elf_info_to_howto ppc64_elf_info_to_howto
6319 #ifdef EM_CYGNUS_POWERPC
6320 #define ELF_MACHINE_ALT1 EM_CYGNUS_POWERPC
6321 #endif
6323 #ifdef EM_PPC_OLD
6324 #define ELF_MACHINE_ALT2 EM_PPC_OLD
6325 #endif
6327 #define elf_backend_want_got_sym 0
6328 #define elf_backend_want_plt_sym 0
6329 #define elf_backend_plt_alignment 3
6330 #define elf_backend_plt_not_loaded 1
6331 #define elf_backend_got_symbol_offset 0
6332 #define elf_backend_got_header_size 8
6333 #define elf_backend_plt_header_size PLT_INITIAL_ENTRY_SIZE
6334 #define elf_backend_can_gc_sections 1
6335 #define elf_backend_can_refcount 1
6336 #define elf_backend_rela_normal 1
6338 #define bfd_elf64_bfd_reloc_type_lookup ppc64_elf_reloc_type_lookup
6339 #define bfd_elf64_bfd_merge_private_bfd_data ppc64_elf_merge_private_bfd_data
6340 #define bfd_elf64_bfd_link_hash_table_create ppc64_elf_link_hash_table_create
6341 #define bfd_elf64_bfd_link_hash_table_free ppc64_elf_link_hash_table_free
6343 #define elf_backend_object_p ppc64_elf_object_p
6344 #define elf_backend_create_dynamic_sections ppc64_elf_create_dynamic_sections
6345 #define elf_backend_copy_indirect_symbol ppc64_elf_copy_indirect_symbol
6346 #define elf_backend_check_relocs ppc64_elf_check_relocs
6347 #define elf_backend_gc_mark_hook ppc64_elf_gc_mark_hook
6348 #define elf_backend_gc_sweep_hook ppc64_elf_gc_sweep_hook
6349 #define elf_backend_adjust_dynamic_symbol ppc64_elf_adjust_dynamic_symbol
6350 #define elf_backend_hide_symbol ppc64_elf_hide_symbol
6351 #define elf_backend_always_size_sections ppc64_elf_func_desc_adjust
6352 #define elf_backend_size_dynamic_sections ppc64_elf_size_dynamic_sections
6353 #define elf_backend_relocate_section ppc64_elf_relocate_section
6354 #define elf_backend_finish_dynamic_symbol ppc64_elf_finish_dynamic_symbol
6355 #define elf_backend_reloc_type_class ppc64_elf_reloc_type_class
6356 #define elf_backend_finish_dynamic_sections ppc64_elf_finish_dynamic_sections