| blob | 7c6ec10b276501521491a6312f8619ca98af94d3 |
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 boolean ppc64_elf_object_p
57 static 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 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 boolean
1658 {
1659 /* Check if we have the same endianess. */
1662 {
1667 else
1674 }
1677 }
1678 \f
1679 /* The following functions are specific to the ELF linker, while
1680 functions above are used generally. Those named ppc64_elf_* are
1681 called by the main ELF linker code. They appear in this file more
1682 or less in the order in which they are called. eg.
1683 ppc64_elf_check_relocs is called early in the link process,
1684 ppc64_elf_finish_dynamic_sections is one of the last functions
1685 called.
1687 PowerPC64-ELF uses a similar scheme to PowerPC64-XCOFF in that
1688 functions have both a function code symbol and a function descriptor
1689 symbol. A call to foo in a relocatable object file looks like:
1691 . .text
1692 . x:
1693 . bl .foo
1694 . nop
1696 The function definition in another object file might be:
1698 . .section .opd
1699 . foo: .quad .foo
1700 . .quad .TOC.@tocbase
1701 . .quad 0
1702 .
1703 . .text
1704 . .foo: blr
1706 When the linker resolves the call during a static link, the branch
1707 unsurprisingly just goes to .foo and the .opd information is unused.
1708 If the function definition is in a shared library, things are a little
1709 different: The call goes via a plt call stub, the opd information gets
1710 copied to the plt, and the linker patches the nop.
1712 . x:
1713 . bl .foo_stub
1714 . ld 2,40(1)
1715 .
1716 .
1717 . .foo_stub:
1718 . addis 12,2,Lfoo@toc@ha # in practice, the call stub
1719 . addi 12,12,Lfoo@toc@l # is slightly optimised, but
1720 . std 2,40(1) # this is the general idea
1721 . ld 11,0(12)
1722 . ld 2,8(12)
1723 . mtctr 11
1724 . ld 11,16(12)
1725 . bctr
1726 .
1727 . .section .plt
1728 . Lfoo: reloc (R_PPC64_JMP_SLOT, foo)
1730 The "reloc ()" notation is supposed to indicate that the linker emits
1731 an R_PPC64_JMP_SLOT reloc against foo. The dynamic linker does the opd
1732 copying.
1734 What are the difficulties here? Well, firstly, the relocations
1735 examined by the linker in check_relocs are against the function code
1736 sym .foo, while the dynamic relocation in the plt is emitted against
1737 the function descriptor symbol, foo. Somewhere along the line, we need
1738 to carefully copy dynamic link information from one symbol to the other.
1739 Secondly, the generic part of the elf linker will make .foo a dynamic
1740 symbol as is normal for most other backends. We need foo dynamic
1741 instead, at least for an application final link. However, when
1742 creating a shared library containing foo, we need to have both symbols
1743 dynamic so that references to .foo are satisfied during the early
1744 stages of linking. Otherwise the linker might decide to pull in a
1745 definition from some other object, eg. a static library. */
1747 /* The linker needs to keep track of the number of relocs that it
1748 decides to copy as dynamic relocs in check_relocs for each symbol.
1749 This is so that it can later discard them if they are found to be
1750 unnecessary. We store the information in a field extending the
1751 regular ELF linker hash table. */
1753 struct ppc_dyn_relocs
1754 {
1757 /* The input section of the reloc. */
1760 /* Total number of relocs copied for the input section. */
1761 bfd_size_type count;
1763 /* Number of pc-relative relocs copied for the input section. */
1764 bfd_size_type pc_count;
1765 };
1767 /* Of those relocs that might be copied as dynamic relocs, this macro
1768 selects between relative and absolute types. */
1770 #define IS_ABSOLUTE_RELOC(RTYPE) \
1771 ((RTYPE) != R_PPC64_REL32 \
1772 && (RTYPE) != R_PPC64_REL64 \
1773 && (RTYPE) != R_PPC64_ADDR30)
1775 /* Section name for stubs is the associated section name plus this
1776 string. */
1779 /* Linker stubs.
1780 ppc_stub_long_branch:
1781 Used when a 14 bit branch (or even a 24 bit branch) can't reach its
1782 destination, but a 24 bit branch in a stub section will reach.
1783 . b dest
1785 ppc_stub_plt_branch:
1786 Similar to the above, but a 24 bit branch in the stub section won't
1787 reach its destination.
1788 . addis %r12,%r2,xxx@ha
1789 . ld %r11,xxx@l(%r12)
1790 . mtctr %r11
1791 . bctr
1793 ppc_stub_plt_call:
1794 Used to call a function in a shared library.
1795 . addis %r12,%r2,xxx@ha
1796 . std %r2,40(%r1)
1797 . ld %r11,xxx+0@l(%r12)
1798 . ld %r2,xxx+8@l(%r12)
1799 . mtctr %r11
1800 . ld %r11,xxx+16@l(%r12)
1801 . bctr
1802 */
1805 ppc_stub_none,
1806 ppc_stub_long_branch,
1807 ppc_stub_plt_branch,
1808 ppc_stub_plt_call
1809 };
1813 /* Base hash table entry structure. */
1816 /* The stub section. */
1819 /* Offset within stub_sec of the beginning of this stub. */
1820 bfd_vma stub_offset;
1822 /* Given the symbol's value and its section we can determine its final
1823 value when building the stubs (so the stub knows where to jump. */
1824 bfd_vma target_value;
1829 /* The symbol table entry, if any, that this was derived from. */
1832 /* Where this stub is being called from, or, in the case of combined
1833 stub sections, the first input section in the group. */
1835 };
1839 /* Base hash table entry structure. */
1842 /* Offset within .branch_lt. */
1845 /* Generation marker. */
1847 };
1849 struct ppc_link_hash_entry
1850 {
1853 /* A pointer to the most recently used stub hash entry against this
1854 symbol. */
1857 /* Track dynamic relocs copied for this symbol. */
1860 /* Link between function code and descriptor symbols. */
1863 /* Flag function code and descriptor symbols. */
1867 };
1869 /* ppc64 ELF linker hash table. */
1871 struct ppc_link_hash_table
1872 {
1875 /* The stub hash table. */
1878 /* Another hash table for plt_branch stubs. */
1881 /* Linker stub bfd. */
1884 /* Linker call-backs. */
1888 /* Array to keep track of which stub sections have been created, and
1889 information on stub grouping. */
1891 /* This is the section to which stubs in the group will be attached. */
1893 /* The stub section. */
1897 /* Assorted information used by ppc64_elf_size_stubs. */
1901 /* Short-cuts to get to dynamic linker sections. */
1913 /* Set on error. */
1916 /* Flag set when small branches are detected. Used to
1917 select suitable defaults for the stub group size. */
1920 /* Set if we detect a reference undefined weak symbol. */
1923 /* Incremented every time we size stubs. */
1926 /* Small local sym to section mapping cache. */
1928 };
1938 static void ppc64_elf_link_hash_table_free
1948 static boolean create_linkage_sections
1950 static boolean create_got_section
1952 static boolean ppc64_elf_create_dynamic_sections
1954 static void ppc64_elf_copy_indirect_symbol
1957 static boolean ppc64_elf_check_relocs
1963 static boolean ppc64_elf_gc_sweep_hook
1966 static boolean func_desc_adjust
1968 static boolean ppc64_elf_func_desc_adjust
1970 static boolean ppc64_elf_adjust_dynamic_symbol
1972 static void ppc64_elf_hide_symbol
1974 static boolean edit_opd
1976 static boolean allocate_dynrelocs
1978 static boolean readonly_dynrelocs
1980 static enum elf_reloc_type_class ppc64_elf_reloc_type_class
1982 static boolean ppc64_elf_size_dynamic_sections
1989 static boolean ppc_build_one_stub
1991 static boolean ppc_size_one_stub
1993 static void group_sections
1995 static boolean ppc64_elf_relocate_section
1998 asection **));
1999 static boolean ppc64_elf_finish_dynamic_symbol
2001 Elf_Internal_Sym *));
2002 static boolean ppc64_elf_finish_dynamic_sections
2005 /* Get the ppc64 ELF linker hash table from a link_info structure. */
2007 #define ppc_hash_table(p) \
2008 ((struct ppc_link_hash_table *) ((p)->hash))
2010 #define ppc_stub_hash_lookup(table, string, create, copy) \
2011 ((struct ppc_stub_hash_entry *) \
2012 bfd_hash_lookup ((table), (string), (create), (copy)))
2014 #define ppc_branch_hash_lookup(table, string, create, copy) \
2015 ((struct ppc_branch_hash_entry *) \
2016 bfd_hash_lookup ((table), (string), (create), (copy)))
2018 /* Create an entry in the stub hash table. */
2025 {
2026 /* Allocate the structure if it has not already been allocated by a
2027 subclass. */
2029 {
2033 }
2035 /* Call the allocation method of the superclass. */
2038 {
2041 /* Initialize the local fields. */
2050 }
2053 }
2055 /* Create an entry in the branch hash table. */
2062 {
2063 /* Allocate the structure if it has not already been allocated by a
2064 subclass. */
2066 {
2070 }
2072 /* Call the allocation method of the superclass. */
2075 {
2078 /* Initialize the local fields. */
2082 }
2085 }
2087 /* Create an entry in a ppc64 ELF linker hash table. */
2094 {
2095 /* Allocate the structure if it has not already been allocated by a
2096 subclass. */
2098 {
2102 }
2104 /* Call the allocation method of the superclass. */
2107 {
2116 }
2119 }
2121 /* Create a ppc64 ELF linker hash table. */
2126 {
2135 {
2138 }
2140 /* Init the stub hash table too. */
2144 /* And the branch hash table. */
2169 }
2171 /* Free the derived linker hash table. */
2173 static void
2176 {
2182 }
2184 /* Build a name for an entry in the stub hash table. */
2192 {
2194 bfd_size_type len;
2196 /* rel->r_addend is actually 64 bit, but who uses more than +/- 2^31
2197 offsets from a sym as a branch target? In fact, we could
2198 probably assume the addend is always zero. */
2202 {
2206 {
2211 }
2212 }
2213 else
2214 {
2218 {
2224 }
2225 }
2227 }
2229 /* Look up an entry in the stub hash. Stub entries are cached because
2230 creating the stub name takes a bit of time. */
2239 {
2244 /* If this input section is part of a group of sections sharing one
2245 stub section, then use the id of the first section in the group.
2246 Stub names need to include a section id, as there may well be
2247 more than one stub used to reach say, printf, and we need to
2248 distinguish between them. */
2254 {
2256 }
2257 else
2258 {
2271 }
2274 }
2276 /* Add a new stub entry to the stub hash. Not all fields of the new
2277 stub entry are initialised. */
2284 {
2292 {
2295 {
2297 bfd_size_type len;
2312 }
2314 }
2316 /* Enter this entry into the linker stub hash table. */
2320 {
2323 stub_name);
2325 }
2331 }
2333 /* Create sections for linker generated code. */
2335 static boolean
2339 {
2341 flagword flags;
2345 /* Create .sfpr for code to save and restore fp regs. */
2354 /* Create .glink for lazy dynamic linking support. */
2361 /* Create .branch_lt for plt_branch stubs. */
2371 {
2379 }
2381 }
2383 /* Create .got and .rela.got sections in DYNOBJ, and set up
2384 shortcuts to them in our hash table. */
2386 static boolean
2390 {
2410 }
2412 /* Create the dynamic sections, and set up shortcuts. */
2414 static boolean
2418 {
2439 }
2441 /* Copy the extra info we tack onto an elf_link_hash_entry. */
2443 static void
2447 {
2454 {
2456 {
2463 /* Add reloc counts against the weak sym to the strong sym
2464 list. Merge any entries against the same section. */
2466 {
2471 {
2476 }
2479 }
2481 }
2485 }
2492 }
2494 /* Set a flag, used by ppc64_elf_gc_mark_hook, on the entry symbol and
2495 symbols undefined on the command-line. */
2497 boolean
2500 {
2506 {
2512 }
2514 }
2516 /* Look through the relocs for a section during the first phase, and
2517 calculate needed space in the global offset table, procedure
2518 linkage table, and dynamic reloc sections. */
2520 static boolean
2526 {
2542 sym_hashes_end = (sym_hashes
2549 {
2550 /* Garbage collection needs some extra help with .opd sections.
2551 We don't want to necessarily keep everything referenced by
2552 relocs in .opd, as that would keep all functions. Instead,
2553 if we reference an .opd symbol (a function descriptor), we
2554 want to keep the function code symbol's section. This is
2555 easy for global symbols, but for local syms we need to keep
2556 information about the associated function section. Later, if
2557 edit_opd deletes entries, we'll use this array to adjust
2558 local syms in .opd. */
2562 };
2563 bfd_size_type amt;
2570 }
2580 {
2588 else
2593 {
2594 /* GOT16 relocations */
2602 /* This symbol requires a global offset table entry. */
2608 {
2610 }
2611 else
2612 {
2615 /* This is a global offset table entry for a local symbol. */
2618 {
2619 bfd_size_type size;
2628 }
2630 }
2638 /* This symbol requires a procedure linkage table entry. We
2639 actually build the entry in adjust_dynamic_symbol,
2640 because this might be a case of linking PIC code without
2641 linking in any dynamic objects, in which case we don't
2642 need to generate a procedure linkage table after all. */
2644 {
2645 /* It does not make sense to have a procedure linkage
2646 table entry for a local symbol. */
2649 }
2656 /* The following relocations don't need to propagate the
2657 relocation if linking a shared object since they are
2658 section relative. */
2673 /* This relocation describes the C++ object vtable hierarchy.
2674 Reconstruct it for later use during GC. */
2680 /* This relocation describes which C++ vtable entries are actually
2681 used. Record for later use during GC. */
2691 /* Fall through. */
2697 {
2698 /* We may need a .plt entry if the function this reloc
2699 refers to is in a shared lib. */
2703 }
2711 {
2717 {
2722 }
2723 }
2729 {
2733 r_symndx);
2738 }
2739 /* Fall through. */
2763 /* Don't propagate .opd relocs. */
2767 /* If we are creating a shared library, and this is a reloc
2768 against a global symbol, or a non PC relative reloc
2769 against a local symbol, then we need to copy the reloc
2770 into the shared library. However, if we are linking with
2771 -Bsymbolic, we do not need to copy a reloc against a
2772 global symbol which is defined in an object we are
2773 including in the link (i.e., DEF_REGULAR is set). At
2774 this point we have not seen all the input files, so it is
2775 possible that DEF_REGULAR is not set now but will be set
2776 later (it is never cleared). In case of a weak definition,
2777 DEF_REGULAR may be cleared later by a strong definition in
2778 a shared library. We account for that possibility below by
2779 storing information in the relocs_copied field of the hash
2780 table entry. A similar situation occurs when creating
2781 shared libraries and symbol visibility changes render the
2782 symbol local.
2784 If on the other hand, we are creating an executable, we
2785 may need to keep relocations for symbols satisfied by a
2786 dynamic library if we manage to avoid copy relocs for the
2787 symbol. */
2802 {
2806 /* We must copy these reloc types into the output file.
2807 Create a reloc section in dynobj and make room for
2808 this reloc. */
2810 {
2814 name = (bfd_elf_string_from_elf_section
2824 {
2829 }
2834 {
2835 flagword flags;
2846 }
2848 }
2850 /* If this is a global symbol, we count the number of
2851 relocations we need for this symbol. */
2853 {
2855 }
2856 else
2857 {
2858 /* Track dynamic relocs needed for local syms too.
2859 We really need local syms available to do this
2860 easily. Oh well. */
2870 }
2874 {
2885 }
2890 }
2895 }
2896 }
2899 }
2901 /* Return the section that should be marked against GC for a given
2902 relocation. */
2911 {
2915 {
2921 {
2928 {
2933 /* Function descriptor syms cause the associated
2934 function code sym section to be marked. */
2938 /* Function entry syms return NULL if they are in .opd
2939 and are not ._start (or others undefined on the ld
2940 command line). Thus we avoid marking all function
2941 sections, as all functions are referenced in .opd. */
2954 }
2955 }
2956 }
2957 else
2958 {
2967 }
2970 }
2972 /* Update the .got, .plt. and dynamic reloc reference counts for the
2973 section being removed. */
2975 static boolean
2981 {
2995 {
3003 {
3011 {
3015 }
3016 else
3017 {
3020 }
3029 {
3033 }
3041 {
3045 }
3051 {
3061 {
3067 }
3068 }
3093 {
3103 {
3108 }
3109 }
3114 }
3115 }
3117 }
3119 /* Called via elf_link_hash_traverse to transfer dynamic linking
3120 information on function code symbol entries to their corresponding
3121 function descriptor symbol entries. */
3122 static boolean
3125 PTR inf;
3126 {
3139 /* If this is a function code symbol, transfer dynamic linking
3140 information to the function descriptor symbol. */
3151 {
3153 boolean force_local;
3155 /* Find the corresponding function descriptor symbol. Create it
3156 as undefined if necessary. */
3166 {
3184 {
3186 }
3189 }
3196 {
3201 & (ELF_LINK_HASH_REF_REGULAR
3202 | ELF_LINK_HASH_REF_DYNAMIC
3203 | ELF_LINK_HASH_REF_REGULAR_NONWEAK
3206 {
3209 }
3213 }
3215 /* Now that the info is on the function descriptor, clear the
3216 function code sym info. Any function code syms for which we
3217 don't have a definition in a regular file, we force local.
3218 This prevents a shared library from exporting syms that have
3219 been imported from another library. Function code syms that
3220 are really in the library we must leave global to prevent the
3221 linker dragging in a definition from a static library. */
3231 }
3234 }
3236 #define MIN_SAVE_FPR 14
3237 #define MAX_SAVE_FPR 31
3239 /* Called near the start of bfd_elf_size_dynamic_sections. We use
3240 this hook to a) provide some gcc support functions, and b) transfer
3241 dynamic linking information gathered so far on function code symbol
3242 entries, to their corresponding function descriptor symbol entries. */
3243 static boolean
3247 {
3259 /* We don't have any relocs. */
3262 /* First provide any missing ._savef* and ._restf* functions. */
3265 {
3271 {
3280 }
3281 }
3285 {
3291 {
3301 }
3302 }
3310 {
3312 {
3315 }
3318 }
3326 {
3331 }
3333 {
3336 }
3339 {
3344 }
3347 {
3349 }
3352 }
3354 /* Adjust a symbol defined by a dynamic object and referenced by a
3355 regular object. The current definition is in some section of the
3356 dynamic object, but we're not including those sections. We have to
3357 change the definition to something the rest of the link can
3358 understand. */
3360 static boolean
3364 {
3373 /* Deal with function syms. */
3376 {
3377 /* Clear procedure linkage table information for any symbol that
3378 won't need a .plt entry. */
3385 {
3388 }
3390 }
3391 else
3394 /* If this is a weak symbol, and there is a real definition, the
3395 processor independent code will have arranged for us to see the
3396 real definition first, and we can just use the same value. */
3398 {
3404 }
3406 /* This is a reference to a symbol defined by a dynamic object which
3407 is not a function. */
3409 /* If we are creating a shared library, we must presume that the
3410 only references to the symbol are via the global offset table.
3411 For such cases we need not do anything here; the relocations will
3412 be handled correctly by relocate_section. */
3416 /* If there are no references to this symbol that do not use the
3417 GOT, we don't need to generate a copy reloc. */
3423 {
3427 }
3429 /* If we didn't find any dynamic relocs in read-only sections, then
3430 we'll be keeping the dynamic relocs and avoiding the copy reloc. */
3432 {
3435 }
3437 /* We must allocate the symbol in our .dynbss section, which will
3438 become part of the .bss section of the executable. There will be
3439 an entry for this symbol in the .dynsym section. The dynamic
3440 object will contain position independent code, so all references
3441 from the dynamic object to this symbol will go through the global
3442 offset table. The dynamic linker will use the .dynsym entry to
3443 determine the address it must put in the global offset table, so
3444 both the dynamic object and the regular object will refer to the
3445 same memory location for the variable. */
3447 /* We must generate a R_PPC_COPY reloc to tell the dynamic linker to
3448 copy the initial value out of the dynamic object and into the
3449 runtime process image. We need to remember the offset into the
3450 .rela.bss section we are going to use. */
3452 {
3455 }
3457 /* We need to figure out the alignment required for this symbol. I
3458 have no idea how ELF linkers handle this. */
3463 /* Apply the required alignment. */
3467 {
3470 }
3472 /* Define the symbol as being at this point in the section. */
3476 /* Increment the section size to make room for the symbol. */
3480 }
3482 /* If given a function descriptor symbol, hide both the function code
3483 sym and the descriptor. */
3484 static void
3488 boolean force_local;
3489 {
3493 {
3497 {
3502 /* We aren't supposed to use alloca in BFD because on
3503 systems which do not have alloca the version in libiberty
3504 calls xmalloc, which might cause the program to crash
3505 when it runs out of memory. This function doesn't have a
3506 return status, so there's no way to gracefully return an
3507 error. So cheat. We know that string[-1] can be safely
3508 dereferenced; It's either a string in an ELF string
3509 table, or allocated in an objalloc structure. */
3518 /* Unfortunately, if it so happens that the string we were
3519 looking for was allocated immediately before this string,
3520 then we overwrote the string terminator. That's the only
3521 reason the lookup should fail. */
3523 {
3529 }
3531 {
3534 }
3535 }
3538 }
3539 }
3541 static boolean
3545 {
3552 {
3558 bfd_vma offset;
3560 boolean need_edit;
3573 /* Look through the section relocs. */
3581 /* Read the relocations. */
3588 /* First run through the relocs to check they are sane, and to
3589 determine whether we need to edit this opd section. */
3594 {
3601 /* .opd contains a regular array of 24 byte entries. We're
3602 only interested in the reloc pointing to a function entry
3603 point. */
3609 {
3615 }
3624 {
3625 /* If someone messes with .opd alignment then after a
3626 "ld -r" we might have padding in the middle of .opd.
3627 Also, there's nothing to prevent someone putting
3628 something silly in .opd with the assembler. No .opd
3629 optimization for them! */
3635 }
3642 {
3650 }
3651 else
3652 {
3654 {
3662 }
3668 }
3671 {
3678 }
3680 /* opd entries are always for functions defined in the
3681 current input bfd. If the symbol isn't defined in the
3682 input bfd, then we won't be using the function in this
3683 bfd; It must be defined in a linkonce section in another
3684 bfd, or is weak. It's also possible that we are
3685 discarding the function due to a linker script /DISCARD/,
3686 which we test for via the output_section. */
3692 }
3695 {
3698 boolean skip;
3700 /* This seems a waste of time as input .opd sections are all
3701 zeros as generated by gcc, but I suppose there's no reason
3702 this will always be so. We might start putting something in
3703 the third word of .opd entries. */
3705 {
3710 {
3714 error_free_rel:
3718 }
3721 }
3731 {
3733 {
3744 {
3752 }
3753 else
3754 {
3761 }
3766 {
3768 {
3769 /* Arrange for the function descriptor sym
3770 to be dropped. */
3779 }
3780 }
3781 else
3782 {
3783 /* We'll be keeping this opd entry. */
3786 {
3787 /* Redefine the function descriptor symbol
3788 to this location in the opd section.
3789 We've checked above that opd relocs are
3790 ordered. */
3798 }
3799 else
3800 {
3801 /* Local syms are a bit tricky. We could
3802 tweak them as they can be cached, but
3803 we'd need to look through the local syms
3804 for the function descriptor sym which we
3805 don't have at the moment. So keep an
3806 array of adjustments. */
3809 }
3814 }
3817 }
3819 /* We need to adjust any reloc offsets to point to the
3820 new opd entries. While we're at it, we may as well
3821 remove redundant relocs. */
3823 {
3828 }
3829 }
3833 }
3839 {
3842 else
3844 }
3845 }
3848 }
3850 /* This is the condition under which ppc64_elf_finish_dynamic_symbol
3851 will be called from elflink.h. If elflink.h doesn't call our
3852 finish_dynamic_symbol routine, we'll need to do something about
3853 initializing any .plt and .got entries in ppc64_elf_relocate_section. */
3854 #define WILL_CALL_FINISH_DYNAMIC_SYMBOL(DYN, INFO, H) \
3855 ((DYN) \
3856 && ((INFO)->shared \
3857 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) \
3858 && ((H)->dynindx != -1 \
3859 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0))
3861 /* Allocate space in .plt, .got and associated reloc sections for
3862 dynamic relocs. */
3864 static boolean
3867 PTR inf;
3868 {
3887 {
3891 {
3892 /* If this is the first .plt entry, make room for the special
3893 first entry. */
3900 /* Make room for this entry. */
3903 /* Make room for the .glink code. */
3907 /* We need bigger stubs past index 32767. */
3912 /* We also need to make an entry in the .rela.plt section. */
3915 }
3916 else
3917 {
3920 }
3921 }
3922 else
3923 {
3926 }
3929 {
3930 boolean dyn;
3932 /* Make sure this symbol is output as a dynamic symbol.
3933 Undefined weak syms won't yet be marked as dynamic. */
3936 {
3939 }
3947 }
3948 else
3955 /* In the shared -Bsymbolic case, discard space allocated for
3956 dynamic pc-relative relocs against symbols which turn out to be
3957 defined in regular objects. For the normal shared case, discard
3958 space for relocs that have become local due to symbol visibility
3959 changes. */
3962 {
3966 {
3970 {
3975 else
3977 }
3978 }
3979 }
3980 else
3981 {
3982 /* For the non-shared case, discard space for relocs against
3983 symbols which turn out to need copy relocs or are not
3984 dynamic. */
3992 {
3993 /* Make sure this symbol is output as a dynamic symbol.
3994 Undefined weak syms won't yet be marked as dynamic. */
3997 {
4000 }
4002 /* If that succeeded, we know we'll be keeping all the
4003 relocs. */
4006 }
4010 keep: ;
4011 }
4013 /* Finally, allocate space. */
4015 {
4018 }
4021 }
4023 /* Find any dynamic relocs that apply to read-only sections. */
4025 static boolean
4028 PTR inf;
4029 {
4038 {
4042 {
4047 /* Not an error, just cut short the traversal. */
4049 }
4050 }
4052 }
4054 /* Set the sizes of the dynamic sections. */
4056 static boolean
4060 {
4064 boolean relocs;
4073 {
4074 /* Set the contents of the .interp section to the interpreter. */
4076 {
4082 }
4083 }
4085 /* Set up .got offsets for local syms, and space for local dynamic
4086 relocs. */
4088 {
4091 bfd_size_type locsymcount;
4099 {
4106 {
4109 {
4110 /* Input section has been discarded, either because
4111 it is a copy of a linkonce section or due to
4112 linker script /DISCARD/, so we'll be discarding
4113 the relocs too. */
4114 }
4116 {
4121 }
4122 }
4123 }
4135 {
4137 {
4142 }
4143 else
4145 }
4146 }
4151 /* Allocate global sym .plt and .got entries, and space for global
4152 sym dynamic relocs. */
4155 /* We now have determined the sizes of the various dynamic sections.
4156 Allocate memory for them. */
4159 {
4164 /* These haven't been allocated yet; don't strip. */
4169 {
4170 /* Strip this section if we don't need it; see the
4171 comment below. */
4172 }
4174 {
4176 {
4177 /* If we don't need this section, strip it from the
4178 output file. This is mostly to handle .rela.bss and
4179 .rela.plt. We must create both sections in
4180 create_dynamic_sections, because they must be created
4181 before the linker maps input sections to output
4182 sections. The linker does that before
4183 adjust_dynamic_symbol is called, and it is that
4184 function which decides whether anything needs to go
4185 into these sections. */
4186 }
4187 else
4188 {
4192 /* We use the reloc_count field as a counter if we need
4193 to copy relocs into the output file. */
4195 }
4196 }
4197 else
4198 {
4199 /* It's not one of our sections, so don't allocate space. */
4201 }
4204 {
4207 }
4209 /* .plt is in the bss section. We don't initialise it. */
4213 /* Allocate memory for the section contents. We use bfd_zalloc
4214 here in case unused entries are not reclaimed before the
4215 section's contents are written out. This should not happen,
4216 but this way if it does, we get a R_PPC64_NONE reloc instead
4217 of garbage. */
4221 }
4224 {
4225 /* Add some entries to the .dynamic section. We fill in the
4226 values later, in ppc64_elf_finish_dynamic_sections, but we
4227 must add the entries now so that we get the correct size for
4228 the .dynamic section. The DT_DEBUG entry is filled in by the
4229 dynamic linker and used by the debugger. */
4230 #define add_dynamic_entry(TAG, VAL) \
4231 bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
4234 {
4237 }
4240 {
4247 }
4250 {
4254 }
4257 {
4263 /* If any dynamic relocs apply to a read-only section,
4264 then we need a DT_TEXTREL entry. */
4270 {
4273 }
4274 }
4275 }
4276 #undef add_dynamic_entry
4279 }
4281 /* Determine the type of stub needed, if any, for a call. */
4288 bfd_vma destination;
4289 {
4291 bfd_vma location;
4292 bfd_vma branch_offset;
4293 bfd_vma max_branch_offset;
4297 {
4301 {
4304 }
4309 }
4311 /* Determine where the call point is. */
4319 /* Determine if a long branch stub is needed. */
4325 /* We need a stub. Figure out whether a long_branch or plt_branch
4326 is needed later. */
4330 }
4332 /* Build a .plt call stub. */
4340 {
4341 #define PPC_LO(v) ((v) & 0xffff)
4342 #define PPC_HI(v) (((v) >> 16) & 0xffff)
4343 #define PPC_HA(v) PPC_HI ((v) + 0x8000)
4362 }
4364 static boolean
4367 PTR in_arg;
4368 {
4378 bfd_vma off;
4381 /* Massage our args to the form they really have. */
4388 /* Make a note of the offset within the stubs for this entry. */
4395 {
4397 /* Branches are relative. This is where we are going to. */
4402 /* And this is where we are coming from. */
4418 {
4423 }
4433 {
4434 /* Create a reloc for the branch lookup table entry. */
4435 Elf_Internal_Rela rela;
4447 }
4456 {
4463 }
4474 /* Do the best we can for shared libraries built without
4475 exporting ".foo" for each "foo". This can happen when symbol
4476 versioning scripts strip all bar a subset of symbols. */
4479 {
4480 /* Point the symbol at the stub. There may be multiple stubs,
4481 we don't really care; The main thing is to make this sym
4482 defined somewhere. */
4486 }
4488 /* Now build the stub. */
4500 {
4507 }
4516 }
4520 }
4522 /* As above, but don't actually build the stub. Just bump offset so
4523 we know stub section sizes, and select plt_branch stubs where
4524 long_branch stubs won't do. */
4526 static boolean
4529 PTR in_arg;
4530 {
4533 bfd_vma off;
4536 /* Massage our args to the form they really have. */
4541 {
4551 }
4552 else
4553 {
4554 /* ppc_stub_long_branch or ppc_stub_plt_branch. */
4566 {
4573 {
4578 }
4581 {
4585 }
4588 }
4589 }
4593 }
4595 /* Set up various things so that we can make a list of input sections
4596 for each output section included in the link. Returns -1 on error,
4597 0 when no stubs will be needed, and 1 on success. */
4599 int
4603 {
4608 bfd_size_type amt;
4615 /* Find the top input section id. */
4619 {
4623 {
4626 }
4627 }
4634 /* We can't use output_bfd->section_count here to find the top output
4635 section index as some sections may have been removed, and
4636 _bfd_strip_section_from_output doesn't renumber the indices. */
4640 {
4643 }
4652 /* For sections we aren't interested in, mark their entries with a
4653 value we can check later. */
4655 do
4662 {
4665 }
4668 }
4670 /* The linker repeatedly calls this function for each input section,
4671 in the order that input sections are linked into output sections.
4672 Build lists of input sections to determine groupings between which
4673 we may insert linker stubs. */
4675 void
4679 {
4683 {
4686 {
4687 /* Steal the link_sec pointer for our list. */
4688 #define PREV_SEC(sec) (htab->stub_group[(sec)->id].link_sec)
4689 /* This happens to make the list in reverse order,
4690 which is what we want. */
4693 }
4694 }
4695 }
4697 /* See whether we can group stub sections together. Grouping stub
4698 sections may result in fewer stubs. More importantly, we need to
4699 put all .init* and .fini* stubs at the beginning of the .init or
4700 .fini output sections respectively, because glibc splits the
4701 _init and _fini functions into multiple parts. Putting a stub in
4702 the middle of a function is not a good idea. */
4704 static void
4707 bfd_size_type stub_group_size;
4708 boolean stubs_always_before_branch;
4709 {
4711 do
4712 {
4717 {
4720 bfd_size_type total;
4725 else
4732 /* OK, the size from the start of CURR to the end is less
4733 than stub_group_size and thus can be handled by one stub
4734 section. (or the tail section is itself larger than
4735 stub_group_size, in which case we may be toast.) We
4736 should really be keeping track of the total size of stubs
4737 added here, as stubs contribute to the final output
4738 section size. That's a little tricky, and this way will
4739 only break if stubs added make the total size more than
4740 2^25, ie. for the default stub_group_size, if stubs total
4741 more than 2834432 bytes, or over 100000 plt call stubs. */
4742 do
4743 {
4745 /* Set up this stub group. */
4747 }
4750 /* But wait, there's more! Input sections up to stub_group_size
4751 bytes before the stub section can be handled by it too. */
4753 {
4758 {
4762 }
4763 }
4765 }
4766 }
4769 #undef PREV_SEC
4770 }
4772 /* Determine and set the size of the stub section for a final link.
4774 The basic idea here is to examine all the relocations looking for
4775 PC-relative calls to a target that is unreachable with a "bl"
4776 instruction. */
4778 boolean
4784 bfd_signed_vma group_size;
4787 {
4788 bfd_size_type stub_group_size;
4789 boolean stubs_always_before_branch;
4792 /* Stash our params away. */
4799 else
4802 {
4803 /* Default values. */
4807 }
4812 {
4816 boolean stub_changed;
4824 {
4829 /* We'll need the symbol table in a second. */
4834 /* Walk over each section attached to the input bfd. */
4838 {
4841 /* If there aren't any relocs, then there's nothing more
4842 to do. */
4847 /* If this section is a link-once section that will be
4848 discarded, then don't create any stubs. */
4853 /* Get the relocs. */
4854 internal_relocs
4861 /* Now examine each relocation. */
4865 {
4870 bfd_vma sym_value;
4871 bfd_vma destination;
4880 {
4883 }
4885 /* Only look for stubs on branch instructions. */
4892 /* Now determine the call target, its name, value,
4893 section. */
4899 {
4900 /* It's a local symbol. */
4905 {
4906 local_syms
4909 local_syms
4915 }
4924 }
4925 else
4926 {
4927 /* It's an external symbol. */
4941 {
4948 }
4950 ;
4952 ;
4953 else
4954 {
4957 }
4958 }
4960 /* Determine what (if any) linker stub is needed. */
4962 destination);
4966 /* Support for grouping stub sections. */
4969 /* Get the name of this stub. */
4977 {
4978 /* The proper stub has already been created. */
4981 }
4985 {
4987 error_ret_free_internal:
4990 error_ret_free_local:
4996 }
5003 }
5005 /* We're done with the internal relocs, free them. */
5008 }
5012 {
5015 else
5017 }
5018 }
5023 /* OK, we've added some stubs. Find out the new size of the
5024 stub sections. */
5028 {
5031 }
5037 /* Ask the linker to do its stuff. */
5039 }
5041 /* It would be nice to strip .branch_lt from the output if the
5042 section is empty, but it's too late. If we strip sections here,
5043 the dynamic symbol table is corrupted since the section symbol
5044 for the stripped section isn't written. */
5047 }
5049 /* Called after we have determined section placement. If sections
5050 move, we'll be called again. Provide a value for TOCstart. */
5052 bfd_vma
5055 {
5057 bfd_vma TOCstart;
5059 /* The TOC consists of sections .got, .toc, .tocbss, .plt in that
5060 order. The TOC starts where the first of these sections starts. */
5069 {
5070 /* This may happen for
5071 o references to TOC base (SYM@toc / TOC[tc0]) without a
5072 .toc directive
5073 o bad linker script
5074 o --gc-sections and empty TOC sections
5076 FIXME: Warn user? */
5078 /* Look for a likely section. We probably won't even be
5079 using TOCstart. */
5097 }
5104 }
5106 /* Build all the stubs associated with the current output file.
5107 The stubs are kept in a hash table attached to the main linker
5108 hash table. This function is called via gldelf64ppc_finish. */
5110 boolean
5113 {
5116 bfd_vma plt_r2;
5122 {
5123 bfd_size_type size;
5125 /* Allocate memory to hold the linker stubs. */
5128 {
5132 }
5134 }
5137 {
5140 /* Build the .glink plt call stub. */
5148 {
5151 }
5153 /* Build the .glink lazy link call stubs. */
5156 {
5158 {
5161 }
5162 else
5163 {
5168 }
5171 indx++;
5173 }
5175 }
5178 {
5183 }
5185 /* Build the stubs as directed by the stub hash table. */
5191 {
5194 }
5198 {
5201 }
5204 }
5206 /* The RELOCATE_SECTION function is called by the ELF backend linker
5207 to handle the relocations for a section.
5209 The relocs are always passed as Rela structures; if the section
5210 actually uses Rel structures, the r_addend field will always be
5211 zero.
5213 This function is responsible for adjust the section contents as
5214 necessary, and (if using Rela relocs and generating a
5215 relocateable output file) adjusting the reloc addend as
5216 necessary.
5218 This function does not have to worry about setting the reloc
5219 address or the reloc symbol index.
5221 LOCAL_SYMS is a pointer to the swapped in local symbols.
5223 LOCAL_SECTIONS is an array giving the section in the input file
5224 corresponding to the st_shndx field of each local symbol.
5226 The global hash table entry for the global symbols can be found
5227 via elf_sym_hashes (input_bfd).
5229 When generating relocateable output, this function must handle
5230 STB_LOCAL/STT_SECTION symbols specially. The output symbol is
5231 going to be the section symbol corresponding to the output
5232 section, which means that the addend must be adjusted
5233 accordingly. */
5235 static boolean
5246 {
5253 bfd_vma TOCstart;
5255 boolean is_opd;
5256 /* Disabled until we sort out how ld should choose 'y' vs 'at'. */
5262 /* Initialize howto table if needed. */
5276 {
5278 bfd_vma offset;
5279 bfd_vma addend;
5280 bfd_reloc_status_type r;
5287 bfd_vma relocation;
5288 boolean unresolved_reloc;
5289 boolean warned;
5292 bfd_vma max_br_offset;
5293 bfd_vma from;
5308 {
5309 /* Relocation value is TOC base. Symbol is ignored. */
5311 }
5313 {
5314 /* It's a local symbol. */
5320 /* rel may have changed, update our copy of addend. */
5324 {
5330 }
5331 }
5332 else
5333 {
5334 /* It's a global symbol. */
5343 {
5346 /* Set a flag that will be cleared later if we find a
5347 relocation value for this symbol. output_section
5348 is typically NULL for symbols satisfied by a shared
5349 library. */
5351 else
5355 }
5357 ;
5362 ;
5363 else
5364 {
5372 }
5373 }
5375 /* First handle relocations that tweak non-addend part of insn. */
5378 {
5382 /* Branch taken prediction relocations. */
5386 /* Fall thru. */
5388 /* Branch not taken prediction relocations. */
5393 {
5394 /* Set 'a' bit. This is 0b00010 in BO field for branch
5395 on CR(BI) insns (BO == 001at or 011at), and 0b01000
5396 for branch on CTR insns (BO == 1a00t or 1a01t). */
5401 else
5403 }
5404 else
5405 {
5406 from = (offset
5410 /* Invert 'y' bit if not the default. */
5413 }
5419 /* A REL24 branching to a linkage function is followed by a
5420 nop. We replace the nop with a ld in order to restore
5421 the TOC base pointer. Only calls to shared objects need
5422 to alter the TOC base. These are recognized by their
5423 need for a PLT entry. */
5429 {
5433 {
5437 {
5441 }
5442 }
5445 {
5446 /* If this is a plain branch rather than a branch
5447 and link, don't require a nop. */
5451 }
5454 {
5460 }
5461 }
5467 {
5468 /* Tweak calls to undefined weak functions to point at a
5469 blr. We can thus call a weak function without first
5470 checking whether the function is defined. We have a
5471 blr at the end of .sfpr. */
5476 from = (offset
5480 /* But let's not be silly about it. If the blr isn't in
5481 reach, just go to the next instruction. */
5485 }
5487 }
5489 /* Set `addend'. */
5491 {
5506 /* GOT16 relocations. Like an ADDR16 using the symbol's
5507 address in the GOT as relocation value instead of the
5508 symbols value itself. Also, create a GOT entry for the
5509 symbol and put the symbol value there. */
5516 {
5517 /* Relocation is to the entry for this symbol in the global
5518 offset table. */
5519 bfd_vma off;
5525 {
5526 boolean dyn;
5538 {
5539 /* This is actually a static link, or it is a
5540 -Bsymbolic link and the symbol is defined
5541 locally, or the symbol was forced to be local
5542 because of a version file. We must initialize
5543 this entry in the global offset table. Since the
5544 offset must always be a multiple of 8, we use the
5545 least significant bit to record whether we have
5546 initialized it already.
5548 When doing a dynamic link, we create a .rel.got
5549 relocation entry to initialize the value. This
5550 is done in the finish_dynamic_symbol routine. */
5553 else
5554 {
5558 }
5559 }
5560 else
5562 }
5563 else
5564 {
5570 /* The offset must always be a multiple of 8. We use
5571 the least significant bit to record whether we have
5572 already processed this entry. */
5575 else
5576 {
5581 {
5582 Elf_Internal_Rela outrel;
5585 /* We need to generate a R_PPC64_RELATIVE reloc
5586 for the dynamic linker. */
5595 }
5598 }
5599 }
5606 /* TOC base (r2) is TOC start plus 0x8000. */
5608 }
5616 /* Relocation is to the entry for this symbol in the
5617 procedure linkage table. */
5619 /* Resolve a PLT reloc against a local symbol directly,
5620 without using the procedure linkage table. */
5626 {
5627 /* We didn't make a PLT entry for this symbol. This
5628 happens when statically linking PIC code, or when
5629 using -Bsymbolic. */
5631 }
5639 /* TOC16 relocs. We want the offset relative to the TOC base,
5640 which is the address of the start of the TOC plus 0x8000.
5641 The TOC consists of sections .got, .toc, .tocbss, and .plt,
5642 in this order. */
5652 /* Relocate against the beginning of the section. */
5669 /* Relocations that may need to be propagated if this is a
5670 dynamic object. */
5693 /* r_symndx will be zero only for relocs against symbols
5694 from removed linkonce sections, or sections discarded by
5695 a linker script. */
5698 /* Fall thru. */
5724 {
5725 Elf_Internal_Rela outrel;
5730 /* When generating a dynamic object, these relocations
5731 are copied into the output file to be resolved at run
5732 time. */
5752 && !is_opd
5759 else
5760 {
5761 /* This symbol is local, or marked to become local,
5762 or this is an opd section reloc which must point
5763 at a local function. */
5767 {
5769 {
5770 /* Lie about opd entries. This case occurs
5771 when building shared libraries and we
5772 reference a function in another shared
5773 lib. The same thing happens for a weak
5774 definition in an application that's
5775 overridden by a strong definition in a
5776 shared lib. (I believe this is a generic
5777 bug in binutils handling of weak syms.)
5778 In these cases we won't use the opd
5779 entry in this lib. */
5781 }
5783 }
5784 else
5785 {
5789 ;
5791 {
5794 }
5795 else
5796 {
5802 /* We are turning this relocation into one
5803 against a section symbol, so subtract out
5804 the output section's address but not the
5805 offset of the input section in the output
5806 section. */
5808 }
5811 }
5812 }
5822 /* If this reloc is against an external symbol, it will
5823 be computed at runtime, so there's no need to do
5824 anything now. */
5827 }
5834 /* We shouldn't ever see these dynamic relocs in relocatable
5835 files. */
5836 /* Fall thru */
5846 /* These ones haven't been implemented yet. */
5856 }
5858 /* Do any further special processing. */
5860 {
5870 /* It's just possible that this symbol is a weak symbol
5871 that's not actually defined anywhere. In that case,
5872 'sec' would be NULL, and we should leave the symbol
5873 alone (it will be set to zero elsewhere in the link). */
5875 /* Add 0x10000 if sign bit in 0:15 is set. */
5891 {
5899 }
5911 branch_check:
5912 /* If the branch is out of reach, then redirect the
5913 call to the local stub for this function. */
5914 from = (offset
5920 {
5921 /* Munge up the value and addend so that we call the stub
5922 rather than the procedure directly. */
5927 }
5929 }
5931 /* Dynamic relocs are not propagated for SEC_DEBUGGING sections
5932 because such sections are not SEC_ALLOC and thus ld.so will
5933 not process them. */
5937 {
5945 }
5948 input_bfd,
5949 input_section,
5950 contents,
5951 offset,
5952 relocation,
5953 addend);
5956 {
5960 {
5963 {
5964 /* Assume this is a call protected by other code that
5965 detects the symbol is undefined. If this is the case,
5966 we can safely ignore the overflow. If not, the
5967 program is hosed anyway, and a little warning isn't
5968 going to help. */
5971 }
5974 }
5975 else
5976 {
5984 }
5987 {
5994 }
5995 else
5996 {
6003 }
6004 }
6005 }
6008 }
6010 /* Finish up dynamic symbol handling. We set the contents of various
6011 dynamic sections here. */
6013 static boolean
6019 {
6028 {
6029 Elf_Internal_Rela rela;
6032 /* This symbol has an entry in the procedure linkage table. Set
6033 it up. */
6040 /* Create a JMP_SLOT reloc to inform the dynamic linker to
6041 fill in the PLT entry. */
6052 }
6055 {
6056 Elf_Internal_Rela rela;
6059 /* This symbol has an entry in the global offset table. Set it
6060 up. */
6069 /* If this is a static link, or it is a -Bsymbolic link and the
6070 symbol is defined locally or was forced to be local because
6071 of a version file, we just want to emit a RELATIVE reloc.
6072 The entry in the global offset table will already have been
6073 initialized in the relocate_section function. */
6079 {
6085 }
6086 else
6087 {
6093 }
6098 }
6101 {
6102 Elf_Internal_Rela rela;
6105 /* This symbol needs a copy reloc. Set it up. */
6121 }
6123 /* Mark some specially defined symbols as absolute. */
6128 }
6130 /* Used to decide how to sort relocs in an optimal manner for the
6131 dynamic linker, before writing them out. */
6133 static enum elf_reloc_type_class
6136 {
6141 {
6150 }
6151 }
6153 /* Finish up the dynamic sections. */
6155 static boolean
6159 {
6169 {
6178 {
6179 Elf_Internal_Dyn dyn;
6185 {
6221 /* Don't count procedure linkage table relocs in the
6222 overall reloc count. */
6226 }
6229 }
6230 }
6233 {
6234 /* Fill in the first entry in the global offset table.
6235 We use it to hold the link-time TOCbase. */
6240 /* Set .got entry size. */
6242 }
6245 {
6246 /* Set .plt entry size. */
6249 }
6252 }
6254 #define TARGET_LITTLE_SYM bfd_elf64_powerpcle_vec
6256 #define TARGET_BIG_SYM bfd_elf64_powerpc_vec
6258 #define ELF_ARCH bfd_arch_powerpc
6259 #define ELF_MACHINE_CODE EM_PPC64
6260 #define ELF_MAXPAGESIZE 0x10000
6261 #define elf_info_to_howto ppc64_elf_info_to_howto
6263 #ifdef EM_CYGNUS_POWERPC
6264 #define ELF_MACHINE_ALT1 EM_CYGNUS_POWERPC
6265 #endif
6267 #ifdef EM_PPC_OLD
6268 #define ELF_MACHINE_ALT2 EM_PPC_OLD
6269 #endif
6271 #define elf_backend_want_got_sym 0
6272 #define elf_backend_want_plt_sym 0
6273 #define elf_backend_plt_alignment 3
6274 #define elf_backend_plt_not_loaded 1
6275 #define elf_backend_got_symbol_offset 0
6276 #define elf_backend_got_header_size 8
6277 #define elf_backend_plt_header_size PLT_INITIAL_ENTRY_SIZE
6278 #define elf_backend_can_gc_sections 1
6279 #define elf_backend_can_refcount 1
6280 #define elf_backend_rela_normal 1
6282 #define bfd_elf64_bfd_reloc_type_lookup ppc64_elf_reloc_type_lookup
6283 #define bfd_elf64_bfd_merge_private_bfd_data ppc64_elf_merge_private_bfd_data
6284 #define bfd_elf64_bfd_link_hash_table_create ppc64_elf_link_hash_table_create
6285 #define bfd_elf64_bfd_link_hash_table_free ppc64_elf_link_hash_table_free
6287 #define elf_backend_object_p ppc64_elf_object_p
6288 #define elf_backend_create_dynamic_sections ppc64_elf_create_dynamic_sections
6289 #define elf_backend_copy_indirect_symbol ppc64_elf_copy_indirect_symbol
6290 #define elf_backend_check_relocs ppc64_elf_check_relocs
6291 #define elf_backend_gc_mark_hook ppc64_elf_gc_mark_hook
6292 #define elf_backend_gc_sweep_hook ppc64_elf_gc_sweep_hook
6293 #define elf_backend_adjust_dynamic_symbol ppc64_elf_adjust_dynamic_symbol
6294 #define elf_backend_hide_symbol ppc64_elf_hide_symbol
6295 #define elf_backend_always_size_sections ppc64_elf_func_desc_adjust
6296 #define elf_backend_size_dynamic_sections ppc64_elf_size_dynamic_sections
6297 #define elf_backend_relocate_section ppc64_elf_relocate_section
6298 #define elf_backend_finish_dynamic_symbol ppc64_elf_finish_dynamic_symbol
6299 #define elf_backend_reloc_type_class ppc64_elf_reloc_type_class
6300 #define elf_backend_finish_dynamic_sections ppc64_elf_finish_dynamic_sections