| blob | 616fbd496afc41f0b9688dec116098fe46501469 |
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
1956 static boolean ppc64_elf_check_relocs
1962 static boolean ppc64_elf_gc_sweep_hook
1965 static boolean func_desc_adjust
1967 static boolean ppc64_elf_func_desc_adjust
1969 static boolean ppc64_elf_adjust_dynamic_symbol
1971 static void ppc64_elf_hide_symbol
1973 static boolean edit_opd
1975 static boolean allocate_dynrelocs
1977 static boolean readonly_dynrelocs
1979 static enum elf_reloc_type_class ppc64_elf_reloc_type_class
1981 static boolean ppc64_elf_size_dynamic_sections
1988 static boolean ppc_build_one_stub
1990 static boolean ppc_size_one_stub
1992 static void group_sections
1994 static boolean ppc64_elf_relocate_section
1997 asection **));
1998 static boolean ppc64_elf_finish_dynamic_symbol
2000 Elf_Internal_Sym *));
2001 static 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 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 boolean
2389 {
2409 }
2411 /* Create the dynamic sections, and set up shortcuts. */
2413 static boolean
2417 {
2438 }
2440 /* Copy the extra info we tack onto an elf_link_hash_entry. */
2442 static void
2445 {
2452 {
2454 {
2461 /* Add reloc counts against the weak sym to the strong sym
2462 list. Merge any entries against the same section. */
2464 {
2469 {
2474 }
2477 }
2479 }
2483 }
2490 }
2492 /* Set a flag, used by ppc64_elf_gc_mark_hook, on the entry symbol and
2493 symbols undefined on the command-line. */
2495 boolean
2498 {
2504 {
2510 }
2512 }
2514 /* Look through the relocs for a section during the first phase, and
2515 calculate needed space in the global offset table, procedure
2516 linkage table, and dynamic reloc sections. */
2518 static boolean
2524 {
2540 sym_hashes_end = (sym_hashes
2547 {
2548 /* Garbage collection needs some extra help with .opd sections.
2549 We don't want to necessarily keep everything referenced by
2550 relocs in .opd, as that would keep all functions. Instead,
2551 if we reference an .opd symbol (a function descriptor), we
2552 want to keep the function code symbol's section. This is
2553 easy for global symbols, but for local syms we need to keep
2554 information about the associated function section. Later, if
2555 edit_opd deletes entries, we'll use this array to adjust
2556 local syms in .opd. */
2560 };
2561 bfd_size_type amt;
2568 }
2578 {
2586 else
2591 {
2592 /* GOT16 relocations */
2600 /* This symbol requires a global offset table entry. */
2606 {
2608 }
2609 else
2610 {
2613 /* This is a global offset table entry for a local symbol. */
2616 {
2617 bfd_size_type size;
2626 }
2628 }
2636 /* This symbol requires a procedure linkage table entry. We
2637 actually build the entry in adjust_dynamic_symbol,
2638 because this might be a case of linking PIC code without
2639 linking in any dynamic objects, in which case we don't
2640 need to generate a procedure linkage table after all. */
2642 {
2643 /* It does not make sense to have a procedure linkage
2644 table entry for a local symbol. */
2647 }
2654 /* The following relocations don't need to propagate the
2655 relocation if linking a shared object since they are
2656 section relative. */
2671 /* This relocation describes the C++ object vtable hierarchy.
2672 Reconstruct it for later use during GC. */
2678 /* This relocation describes which C++ vtable entries are actually
2679 used. Record for later use during GC. */
2689 /* Fall through. */
2695 {
2696 /* We may need a .plt entry if the function this reloc
2697 refers to is in a shared lib. */
2701 }
2709 {
2715 {
2720 }
2721 }
2727 {
2731 r_symndx);
2736 }
2737 /* Fall through. */
2761 /* Don't propagate .opd relocs. */
2765 /* If we are creating a shared library, and this is a reloc
2766 against a global symbol, or a non PC relative reloc
2767 against a local symbol, then we need to copy the reloc
2768 into the shared library. However, if we are linking with
2769 -Bsymbolic, we do not need to copy a reloc against a
2770 global symbol which is defined in an object we are
2771 including in the link (i.e., DEF_REGULAR is set). At
2772 this point we have not seen all the input files, so it is
2773 possible that DEF_REGULAR is not set now but will be set
2774 later (it is never cleared). In case of a weak definition,
2775 DEF_REGULAR may be cleared later by a strong definition in
2776 a shared library. We account for that possibility below by
2777 storing information in the relocs_copied field of the hash
2778 table entry. A similar situation occurs when creating
2779 shared libraries and symbol visibility changes render the
2780 symbol local.
2782 If on the other hand, we are creating an executable, we
2783 may need to keep relocations for symbols satisfied by a
2784 dynamic library if we manage to avoid copy relocs for the
2785 symbol. */
2800 {
2804 /* We must copy these reloc types into the output file.
2805 Create a reloc section in dynobj and make room for
2806 this reloc. */
2808 {
2812 name = (bfd_elf_string_from_elf_section
2822 {
2827 }
2832 {
2833 flagword flags;
2844 }
2846 }
2848 /* If this is a global symbol, we count the number of
2849 relocations we need for this symbol. */
2851 {
2853 }
2854 else
2855 {
2856 /* Track dynamic relocs needed for local syms too.
2857 We really need local syms available to do this
2858 easily. Oh well. */
2868 }
2872 {
2883 }
2888 }
2893 }
2894 }
2897 }
2899 /* Return the section that should be marked against GC for a given
2900 relocation. */
2909 {
2913 {
2919 {
2926 {
2931 /* Function descriptor syms cause the associated
2932 function code sym section to be marked. */
2936 /* Function entry syms return NULL if they are in .opd
2937 and are not ._start (or others undefined on the ld
2938 command line). Thus we avoid marking all function
2939 sections, as all functions are referenced in .opd. */
2952 }
2953 }
2954 }
2955 else
2956 {
2965 }
2968 }
2970 /* Update the .got, .plt. and dynamic reloc reference counts for the
2971 section being removed. */
2973 static boolean
2979 {
2993 {
3001 {
3009 {
3013 }
3014 else
3015 {
3018 }
3027 {
3031 }
3039 {
3043 }
3049 {
3059 {
3065 }
3066 }
3091 {
3101 {
3106 }
3107 }
3112 }
3113 }
3115 }
3117 /* Called via elf_link_hash_traverse to transfer dynamic linking
3118 information on function code symbol entries to their corresponding
3119 function descriptor symbol entries. */
3120 static boolean
3123 PTR inf;
3124 {
3137 /* If this is a function code symbol, transfer dynamic linking
3138 information to the function descriptor symbol. */
3149 {
3151 boolean force_local;
3153 /* Find the corresponding function descriptor symbol. Create it
3154 as undefined if necessary. */
3164 {
3181 {
3183 }
3185 }
3192 {
3197 & (ELF_LINK_HASH_REF_REGULAR
3198 | ELF_LINK_HASH_REF_DYNAMIC
3199 | ELF_LINK_HASH_REF_REGULAR_NONWEAK
3202 {
3205 }
3209 }
3211 /* Now that the info is on the function descriptor, clear the
3212 function code sym info. Any function code syms for which we
3213 don't have a definition in a regular file, we force local.
3214 This prevents a shared library from exporting syms that have
3215 been imported from another library. Function code syms that
3216 are really in the library we must leave global to prevent the
3217 linker dragging in a definition from a static library. */
3227 }
3230 }
3232 #define MIN_SAVE_FPR 14
3233 #define MAX_SAVE_FPR 31
3235 /* Called near the start of bfd_elf_size_dynamic_sections. We use
3236 this hook to a) provide some gcc support functions, and b) transfer
3237 dynamic linking information gathered so far on function code symbol
3238 entries, to their corresponding function descriptor symbol entries. */
3239 static boolean
3243 {
3255 /* We don't have any relocs. */
3258 /* First provide any missing ._savef* and ._restf* functions. */
3261 {
3267 {
3276 }
3277 }
3281 {
3287 {
3297 }
3298 }
3306 {
3308 {
3311 }
3314 }
3322 {
3327 }
3329 {
3332 }
3335 {
3340 }
3343 {
3345 }
3348 }
3350 /* Adjust a symbol defined by a dynamic object and referenced by a
3351 regular object. The current definition is in some section of the
3352 dynamic object, but we're not including those sections. We have to
3353 change the definition to something the rest of the link can
3354 understand. */
3356 static boolean
3360 {
3369 /* Deal with function syms. */
3372 {
3373 /* Clear procedure linkage table information for any symbol that
3374 won't need a .plt entry. */
3381 {
3384 }
3386 }
3387 else
3390 /* If this is a weak symbol, and there is a real definition, the
3391 processor independent code will have arranged for us to see the
3392 real definition first, and we can just use the same value. */
3394 {
3400 }
3402 /* This is a reference to a symbol defined by a dynamic object which
3403 is not a function. */
3405 /* If we are creating a shared library, we must presume that the
3406 only references to the symbol are via the global offset table.
3407 For such cases we need not do anything here; the relocations will
3408 be handled correctly by relocate_section. */
3412 /* If there are no references to this symbol that do not use the
3413 GOT, we don't need to generate a copy reloc. */
3419 {
3423 }
3425 /* If we didn't find any dynamic relocs in read-only sections, then
3426 we'll be keeping the dynamic relocs and avoiding the copy reloc. */
3428 {
3431 }
3433 /* We must allocate the symbol in our .dynbss section, which will
3434 become part of the .bss section of the executable. There will be
3435 an entry for this symbol in the .dynsym section. The dynamic
3436 object will contain position independent code, so all references
3437 from the dynamic object to this symbol will go through the global
3438 offset table. The dynamic linker will use the .dynsym entry to
3439 determine the address it must put in the global offset table, so
3440 both the dynamic object and the regular object will refer to the
3441 same memory location for the variable. */
3443 /* We must generate a R_PPC_COPY reloc to tell the dynamic linker to
3444 copy the initial value out of the dynamic object and into the
3445 runtime process image. We need to remember the offset into the
3446 .rela.bss section we are going to use. */
3448 {
3451 }
3453 /* We need to figure out the alignment required for this symbol. I
3454 have no idea how ELF linkers handle this. */
3459 /* Apply the required alignment. */
3463 {
3466 }
3468 /* Define the symbol as being at this point in the section. */
3472 /* Increment the section size to make room for the symbol. */
3476 }
3478 /* If given a function descriptor symbol, hide both the function code
3479 sym and the descriptor. */
3480 static void
3484 boolean force_local;
3485 {
3489 {
3493 {
3498 /* We aren't supposed to use alloca in BFD because on
3499 systems which do not have alloca the version in libiberty
3500 calls xmalloc, which might cause the program to crash
3501 when it runs out of memory. This function doesn't have a
3502 return status, so there's no way to gracefully return an
3503 error. So cheat. We know that string[-1] can be safely
3504 dereferenced; It's either a string in an ELF string
3505 table, or allocated in an objalloc structure. */
3514 /* Unfortunately, if it so happens that the string we were
3515 looking for was allocated immediately before this string,
3516 then we overwrote the string terminator. That's the only
3517 reason the lookup should fail. */
3519 {
3525 }
3527 {
3530 }
3531 }
3534 }
3535 }
3537 static boolean
3541 {
3548 {
3554 bfd_vma offset;
3556 boolean need_edit;
3569 /* Look through the section relocs. */
3577 /* Read the relocations. */
3584 /* First run through the relocs to check they are sane, and to
3585 determine whether we need to edit this opd section. */
3590 {
3597 /* .opd contains a regular array of 24 byte entries. We're
3598 only interested in the reloc pointing to a function entry
3599 point. */
3605 {
3611 }
3620 {
3621 /* If someone messes with .opd alignment then after a
3622 "ld -r" we might have padding in the middle of .opd.
3623 Also, there's nothing to prevent someone putting
3624 something silly in .opd with the assembler. No .opd
3625 optimization for them! */
3631 }
3638 {
3646 }
3647 else
3648 {
3650 {
3658 }
3664 }
3667 {
3674 }
3677 {
3678 /* OK, we've found a function that's excluded from the
3679 link. */
3681 }
3684 }
3687 {
3690 boolean skip;
3692 /* This seems a waste of time as input .opd sections are all
3693 zeros as generated by gcc, but I suppose there's no reason
3694 this will always be so. We might start putting something in
3695 the third word of .opd entries. */
3697 {
3702 {
3706 error_free_rel:
3710 }
3713 }
3723 {
3725 {
3736 {
3744 }
3745 else
3746 {
3753 }
3757 {
3759 {
3760 /* Arrange for the function descriptor sym
3761 to be dropped. */
3770 }
3771 }
3772 else
3773 {
3774 /* We'll be keeping this opd entry. */
3777 {
3778 /* Redefine the function descriptor symbol
3779 to this location in the opd section.
3780 We've checked above that opd relocs are
3781 ordered. */
3789 }
3790 else
3791 {
3792 /* Local syms are a bit tricky. We could
3793 tweak them as they can be cached, but
3794 we'd need to look through the local syms
3795 for the function descriptor sym which we
3796 don't have at the moment. So keep an
3797 array of adjustments. */
3800 }
3805 }
3808 }
3810 /* We need to adjust any reloc offsets to point to the
3811 new opd entries. While we're at it, we may as well
3812 remove redundant relocs. */
3814 {
3819 }
3820 }
3824 }
3830 {
3833 else
3835 }
3836 }
3839 }
3841 /* This is the condition under which ppc64_elf_finish_dynamic_symbol
3842 will be called from elflink.h. If elflink.h doesn't call our
3843 finish_dynamic_symbol routine, we'll need to do something about
3844 initializing any .plt and .got entries in ppc64_elf_relocate_section. */
3845 #define WILL_CALL_FINISH_DYNAMIC_SYMBOL(DYN, INFO, H) \
3846 ((DYN) \
3847 && ((INFO)->shared \
3848 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0) \
3849 && ((H)->dynindx != -1 \
3850 || ((H)->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) != 0))
3852 /* Allocate space in .plt, .got and associated reloc sections for
3853 dynamic relocs. */
3855 static boolean
3858 PTR inf;
3859 {
3878 {
3882 {
3883 /* If this is the first .plt entry, make room for the special
3884 first entry. */
3891 /* Make room for this entry. */
3894 /* Make room for the .glink code. */
3898 /* We need bigger stubs past index 32767. */
3903 /* We also need to make an entry in the .rela.plt section. */
3906 }
3907 else
3908 {
3911 }
3912 }
3913 else
3914 {
3917 }
3920 {
3921 boolean dyn;
3923 /* Make sure this symbol is output as a dynamic symbol.
3924 Undefined weak syms won't yet be marked as dynamic. */
3927 {
3930 }
3938 }
3939 else
3946 /* In the shared -Bsymbolic case, discard space allocated for
3947 dynamic pc-relative relocs against symbols which turn out to be
3948 defined in regular objects. For the normal shared case, discard
3949 space for relocs that have become local due to symbol visibility
3950 changes. */
3953 {
3957 {
3961 {
3966 else
3968 }
3969 }
3970 }
3971 else
3972 {
3973 /* For the non-shared case, discard space for relocs against
3974 symbols which turn out to need copy relocs or are not
3975 dynamic. */
3983 {
3984 /* Make sure this symbol is output as a dynamic symbol.
3985 Undefined weak syms won't yet be marked as dynamic. */
3988 {
3991 }
3993 /* If that succeeded, we know we'll be keeping all the
3994 relocs. */
3997 }
4001 keep: ;
4002 }
4004 /* Finally, allocate space. */
4006 {
4009 }
4012 }
4014 /* Find any dynamic relocs that apply to read-only sections. */
4016 static boolean
4019 PTR inf;
4020 {
4029 {
4033 {
4038 /* Not an error, just cut short the traversal. */
4040 }
4041 }
4043 }
4045 /* Set the sizes of the dynamic sections. */
4047 static boolean
4051 {
4055 boolean relocs;
4064 {
4065 /* Set the contents of the .interp section to the interpreter. */
4067 {
4073 }
4074 }
4076 /* Set up .got offsets for local syms, and space for local dynamic
4077 relocs. */
4079 {
4082 bfd_size_type locsymcount;
4090 {
4097 {
4100 {
4101 /* Input section has been discarded, either because
4102 it is a copy of a linkonce section or due to
4103 linker script /DISCARD/, so we'll be discarding
4104 the relocs too. */
4105 }
4107 {
4112 }
4113 }
4114 }
4126 {
4128 {
4133 }
4134 else
4136 }
4137 }
4142 /* Allocate global sym .plt and .got entries, and space for global
4143 sym dynamic relocs. */
4146 /* We now have determined the sizes of the various dynamic sections.
4147 Allocate memory for them. */
4150 {
4155 /* These haven't been allocated yet; don't strip. */
4160 {
4161 /* Strip this section if we don't need it; see the
4162 comment below. */
4163 }
4165 {
4167 {
4168 /* If we don't need this section, strip it from the
4169 output file. This is mostly to handle .rela.bss and
4170 .rela.plt. We must create both sections in
4171 create_dynamic_sections, because they must be created
4172 before the linker maps input sections to output
4173 sections. The linker does that before
4174 adjust_dynamic_symbol is called, and it is that
4175 function which decides whether anything needs to go
4176 into these sections. */
4177 }
4178 else
4179 {
4183 /* We use the reloc_count field as a counter if we need
4184 to copy relocs into the output file. */
4186 }
4187 }
4188 else
4189 {
4190 /* It's not one of our sections, so don't allocate space. */
4192 }
4195 {
4198 }
4200 /* .plt is in the bss section. We don't initialise it. */
4204 /* Allocate memory for the section contents. We use bfd_zalloc
4205 here in case unused entries are not reclaimed before the
4206 section's contents are written out. This should not happen,
4207 but this way if it does, we get a R_PPC64_NONE reloc instead
4208 of garbage. */
4212 }
4215 {
4216 /* Add some entries to the .dynamic section. We fill in the
4217 values later, in ppc64_elf_finish_dynamic_sections, but we
4218 must add the entries now so that we get the correct size for
4219 the .dynamic section. The DT_DEBUG entry is filled in by the
4220 dynamic linker and used by the debugger. */
4221 #define add_dynamic_entry(TAG, VAL) \
4222 bfd_elf64_add_dynamic_entry (info, (bfd_vma) (TAG), (bfd_vma) (VAL))
4225 {
4228 }
4231 {
4238 }
4241 {
4245 }
4248 {
4254 /* If any dynamic relocs apply to a read-only section,
4255 then we need a DT_TEXTREL entry. */
4261 {
4264 }
4265 }
4266 }
4267 #undef add_dynamic_entry
4270 }
4272 /* Determine the type of stub needed, if any, for a call. */
4279 bfd_vma destination;
4280 {
4282 bfd_vma location;
4283 bfd_vma branch_offset;
4284 bfd_vma max_branch_offset;
4288 {
4292 {
4295 }
4300 }
4302 /* Determine where the call point is. */
4310 /* Determine if a long branch stub is needed. */
4316 /* We need a stub. Figure out whether a long_branch or plt_branch
4317 is needed later. */
4321 }
4323 /* Build a .plt call stub. */
4331 {
4332 #define PPC_LO(v) ((v) & 0xffff)
4333 #define PPC_HI(v) (((v) >> 16) & 0xffff)
4334 #define PPC_HA(v) PPC_HI ((v) + 0x8000)
4353 }
4355 static boolean
4358 PTR in_arg;
4359 {
4369 bfd_vma off;
4372 /* Massage our args to the form they really have. */
4379 /* Make a note of the offset within the stubs for this entry. */
4386 {
4388 /* Branches are relative. This is where we are going to. */
4393 /* And this is where we are coming from. */
4409 {
4414 }
4424 {
4425 /* Create a reloc for the branch lookup table entry. */
4426 Elf_Internal_Rela rela;
4438 }
4447 {
4454 }
4465 /* Build the .glink lazy link call stub. */
4469 {
4472 }
4473 else
4474 {
4479 }
4486 /* Do the best we can for shared libraries built without
4487 exporting ".foo" for each "foo". This can happen when symbol
4488 versioning scripts strip all bar a subset of symbols. */
4491 {
4492 /* Point the symbol at the stub. There may be multiple stubs,
4493 we don't really care; The main thing is to make this sym
4494 defined somewhere. */
4498 }
4500 /* Now build the stub. */
4512 {
4519 }
4528 }
4532 }
4534 /* As above, but don't actually build the stub. Just bump offset so
4535 we know stub section sizes, and select plt_branch stubs where
4536 long_branch stubs won't do. */
4538 static boolean
4541 PTR in_arg;
4542 {
4545 bfd_vma off;
4548 /* Massage our args to the form they really have. */
4553 {
4563 }
4564 else
4565 {
4566 /* ppc_stub_long_branch or ppc_stub_plt_branch. */
4578 {
4585 {
4590 }
4593 {
4597 }
4600 }
4601 }
4605 }
4607 /* Set up various things so that we can make a list of input sections
4608 for each output section included in the link. Returns -1 on error,
4609 0 when no stubs will be needed, and 1 on success. */
4611 int
4615 {
4620 bfd_size_type amt;
4627 /* Find the top input section id. */
4631 {
4635 {
4638 }
4639 }
4646 /* We can't use output_bfd->section_count here to find the top output
4647 section index as some sections may have been removed, and
4648 _bfd_strip_section_from_output doesn't renumber the indices. */
4652 {
4655 }
4664 /* For sections we aren't interested in, mark their entries with a
4665 value we can check later. */
4667 do
4674 {
4677 }
4680 }
4682 /* The linker repeatedly calls this function for each input section,
4683 in the order that input sections are linked into output sections.
4684 Build lists of input sections to determine groupings between which
4685 we may insert linker stubs. */
4687 void
4691 {
4695 {
4698 {
4699 /* Steal the link_sec pointer for our list. */
4700 #define PREV_SEC(sec) (htab->stub_group[(sec)->id].link_sec)
4701 /* This happens to make the list in reverse order,
4702 which is what we want. */
4705 }
4706 }
4707 }
4709 /* See whether we can group stub sections together. Grouping stub
4710 sections may result in fewer stubs. More importantly, we need to
4711 put all .init* and .fini* stubs at the beginning of the .init or
4712 .fini output sections respectively, because glibc splits the
4713 _init and _fini functions into multiple parts. Putting a stub in
4714 the middle of a function is not a good idea. */
4716 static void
4719 bfd_size_type stub_group_size;
4720 boolean stubs_always_before_branch;
4721 {
4723 do
4724 {
4729 {
4732 bfd_size_type total;
4737 else
4744 /* OK, the size from the start of CURR to the end is less
4745 than stub_group_size and thus can be handled by one stub
4746 section. (or the tail section is itself larger than
4747 stub_group_size, in which case we may be toast.) We
4748 should really be keeping track of the total size of stubs
4749 added here, as stubs contribute to the final output
4750 section size. That's a little tricky, and this way will
4751 only break if stubs added make the total size more than
4752 2^25, ie. for the default stub_group_size, if stubs total
4753 more than 2834432 bytes, or over 100000 plt call stubs. */
4754 do
4755 {
4757 /* Set up this stub group. */
4759 }
4762 /* But wait, there's more! Input sections up to stub_group_size
4763 bytes before the stub section can be handled by it too. */
4765 {
4770 {
4774 }
4775 }
4777 }
4778 }
4781 #undef PREV_SEC
4782 }
4784 /* Determine and set the size of the stub section for a final link.
4786 The basic idea here is to examine all the relocations looking for
4787 PC-relative calls to a target that is unreachable with a "bl"
4788 instruction. */
4790 boolean
4796 bfd_signed_vma group_size;
4799 {
4800 bfd_size_type stub_group_size;
4801 boolean stubs_always_before_branch;
4804 /* Stash our params away. */
4811 else
4814 {
4815 /* Default values. */
4819 }
4824 {
4828 boolean stub_changed;
4836 {
4841 /* We'll need the symbol table in a second. */
4846 /* Walk over each section attached to the input bfd. */
4850 {
4853 /* If there aren't any relocs, then there's nothing more
4854 to do. */
4859 /* If this section is a link-once section that will be
4860 discarded, then don't create any stubs. */
4865 /* Get the relocs. */
4866 internal_relocs
4873 /* Now examine each relocation. */
4877 {
4882 bfd_vma sym_value;
4883 bfd_vma destination;
4892 {
4895 }
4897 /* Only look for stubs on branch instructions. */
4904 /* Now determine the call target, its name, value,
4905 section. */
4911 {
4912 /* It's a local symbol. */
4917 {
4918 local_syms
4921 local_syms
4927 }
4936 }
4937 else
4938 {
4939 /* It's an external symbol. */
4953 {
4960 }
4962 ;
4964 ;
4965 else
4966 {
4969 }
4970 }
4972 /* Determine what (if any) linker stub is needed. */
4974 destination);
4978 /* Support for grouping stub sections. */
4981 /* Get the name of this stub. */
4989 {
4990 /* The proper stub has already been created. */
4993 }
4997 {
4999 error_ret_free_internal:
5002 error_ret_free_local:
5008 }
5015 }
5017 /* We're done with the internal relocs, free them. */
5020 }
5024 {
5027 else
5029 }
5030 }
5035 /* OK, we've added some stubs. Find out the new size of the
5036 stub sections. */
5040 {
5043 }
5049 /* Ask the linker to do its stuff. */
5051 }
5053 /* It would be nice to strip .branch_lt from the output if the
5054 section is empty, but it's too late. If we strip sections here,
5055 the dynamic symbol table is corrupted since the section symbol
5056 for the stripped section isn't written. */
5059 }
5061 /* Called after we have determined section placement. If sections
5062 move, we'll be called again. Provide a value for TOCstart. */
5064 bfd_vma
5067 {
5069 bfd_vma TOCstart;
5071 /* The TOC consists of sections .got, .toc, .tocbss, .plt in that
5072 order. The TOC starts where the first of these sections starts. */
5081 {
5082 /* This may happen for
5083 o references to TOC base (SYM@toc / TOC[tc0]) without a
5084 .toc directive
5085 o bad linker script
5086 o --gc-sections and empty TOC sections
5088 FIXME: Warn user? */
5090 /* Look for a likely section. We probably won't even be
5091 using TOCstart. */
5109 }
5116 }
5118 /* Build all the stubs associated with the current output file.
5119 The stubs are kept in a hash table attached to the main linker
5120 hash table. This function is called via gldelf64ppc_finish. */
5122 boolean
5125 {
5128 bfd_vma plt_r2;
5134 {
5135 bfd_size_type size;
5137 /* Allocate memory to hold the linker stubs. */
5140 {
5144 }
5146 }
5149 {
5150 /* Build the .glink plt call stub. */
5158 {
5161 }
5164 /* Use reloc_count to count entries. */
5166 }
5169 {
5174 }
5176 /* Build the stubs as directed by the stub hash table. */
5183 {
5186 }
5190 {
5193 }
5196 }
5198 /* The RELOCATE_SECTION function is called by the ELF backend linker
5199 to handle the relocations for a section.
5201 The relocs are always passed as Rela structures; if the section
5202 actually uses Rel structures, the r_addend field will always be
5203 zero.
5205 This function is responsible for adjust the section contents as
5206 necessary, and (if using Rela relocs and generating a
5207 relocateable output file) adjusting the reloc addend as
5208 necessary.
5210 This function does not have to worry about setting the reloc
5211 address or the reloc symbol index.
5213 LOCAL_SYMS is a pointer to the swapped in local symbols.
5215 LOCAL_SECTIONS is an array giving the section in the input file
5216 corresponding to the st_shndx field of each local symbol.
5218 The global hash table entry for the global symbols can be found
5219 via elf_sym_hashes (input_bfd).
5221 When generating relocateable output, this function must handle
5222 STB_LOCAL/STT_SECTION symbols specially. The output symbol is
5223 going to be the section symbol corresponding to the output
5224 section, which means that the addend must be adjusted
5225 accordingly. */
5227 static boolean
5238 {
5245 bfd_vma TOCstart;
5247 boolean is_opd;
5248 /* Disabled until we sort out how ld should choose 'y' vs 'at'. */
5254 /* Initialize howto table if needed. */
5268 {
5270 bfd_vma offset;
5271 bfd_vma addend;
5272 bfd_reloc_status_type r;
5279 bfd_vma relocation;
5280 boolean unresolved_reloc;
5281 boolean warned;
5284 bfd_vma max_br_offset;
5285 bfd_vma from;
5300 {
5301 /* Relocation value is TOC base. Symbol is ignored. */
5303 }
5305 {
5306 /* It's a local symbol. */
5312 /* rel may have changed, update our copy of addend. */
5316 {
5322 }
5323 }
5324 else
5325 {
5326 /* It's a global symbol. */
5335 {
5338 /* Set a flag that will be cleared later if we find a
5339 relocation value for this symbol. output_section
5340 is typically NULL for symbols satisfied by a shared
5341 library. */
5343 else
5347 }
5349 ;
5354 ;
5355 else
5356 {
5364 }
5365 }
5367 /* First handle relocations that tweak non-addend part of insn. */
5370 {
5374 /* Branch taken prediction relocations. */
5378 /* Fall thru. */
5380 /* Branch not taken prediction relocations. */
5385 {
5386 /* Set 'a' bit. This is 0b00010 in BO field for branch
5387 on CR(BI) insns (BO == 001at or 011at), and 0b01000
5388 for branch on CTR insns (BO == 1a00t or 1a01t). */
5393 else
5395 }
5396 else
5397 {
5398 from = (offset
5402 /* Invert 'y' bit if not the default. */
5405 }
5411 /* A REL24 branching to a linkage function is followed by a
5412 nop. We replace the nop with a ld in order to restore
5413 the TOC base pointer. Only calls to shared objects need
5414 to alter the TOC base. These are recognized by their
5415 need for a PLT entry. */
5421 {
5425 {
5429 {
5433 }
5434 }
5437 {
5438 /* If this is a plain branch rather than a branch
5439 and link, don't require a nop. */
5443 }
5446 {
5452 }
5453 }
5459 {
5460 /* Tweak calls to undefined weak functions to point at a
5461 blr. We can thus call a weak function without first
5462 checking whether the function is defined. We have a
5463 blr at the end of .sfpr. */
5468 from = (offset
5472 /* But let's not be silly about it. If the blr isn't in
5473 reach, just go to the next instruction. */
5477 }
5479 }
5481 /* Set `addend'. */
5483 {
5498 /* GOT16 relocations. Like an ADDR16 using the symbol's
5499 address in the GOT as relocation value instead of the
5500 symbols value itself. Also, create a GOT entry for the
5501 symbol and put the symbol value there. */
5508 {
5509 /* Relocation is to the entry for this symbol in the global
5510 offset table. */
5511 bfd_vma off;
5517 {
5518 boolean dyn;
5530 {
5531 /* This is actually a static link, or it is a
5532 -Bsymbolic link and the symbol is defined
5533 locally, or the symbol was forced to be local
5534 because of a version file. We must initialize
5535 this entry in the global offset table. Since the
5536 offset must always be a multiple of 8, we use the
5537 least significant bit to record whether we have
5538 initialized it already.
5540 When doing a dynamic link, we create a .rel.got
5541 relocation entry to initialize the value. This
5542 is done in the finish_dynamic_symbol routine. */
5545 else
5546 {
5550 }
5551 }
5552 else
5554 }
5555 else
5556 {
5562 /* The offset must always be a multiple of 8. We use
5563 the least significant bit to record whether we have
5564 already processed this entry. */
5567 else
5568 {
5573 {
5574 Elf_Internal_Rela outrel;
5577 /* We need to generate a R_PPC64_RELATIVE reloc
5578 for the dynamic linker. */
5587 }
5590 }
5591 }
5598 /* TOC base (r2) is TOC start plus 0x8000. */
5600 }
5608 /* Relocation is to the entry for this symbol in the
5609 procedure linkage table. */
5611 /* Resolve a PLT reloc against a local symbol directly,
5612 without using the procedure linkage table. */
5618 {
5619 /* We didn't make a PLT entry for this symbol. This
5620 happens when statically linking PIC code, or when
5621 using -Bsymbolic. */
5623 }
5631 /* TOC16 relocs. We want the offset relative to the TOC base,
5632 which is the address of the start of the TOC plus 0x8000.
5633 The TOC consists of sections .got, .toc, .tocbss, and .plt,
5634 in this order. */
5644 /* Relocate against the beginning of the section. */
5661 /* Relocations that may need to be propagated if this is a
5662 dynamic object. */
5685 /* r_symndx will be zero only for relocs against symbols
5686 from removed linkonce sections, or sections discarded by
5687 a linker script. */
5690 /* Fall thru. */
5716 {
5717 Elf_Internal_Rela outrel;
5722 /* When generating a dynamic object, these relocations
5723 are copied into the output file to be resolved at run
5724 time. */
5744 && !is_opd
5751 else
5752 {
5753 /* This symbol is local, or marked to become local,
5754 or this is an opd section reloc which must point
5755 at a local function. */
5759 {
5761 {
5762 /* Lie about opd entries. This case occurs
5763 when building shared libraries and we
5764 reference a function in another shared
5765 lib. The same thing happens for a weak
5766 definition in an application that's
5767 overridden by a strong definition in a
5768 shared lib. (I believe this is a generic
5769 bug in binutils handling of weak syms.)
5770 In these cases we won't use the opd
5771 entry in this lib. */
5773 }
5775 }
5776 else
5777 {
5781 ;
5783 {
5786 }
5787 else
5788 {
5794 /* We are turning this relocation into one
5795 against a section symbol, so subtract out
5796 the output section's address but not the
5797 offset of the input section in the output
5798 section. */
5800 }
5803 }
5804 }
5814 /* If this reloc is against an external symbol, it will
5815 be computed at runtime, so there's no need to do
5816 anything now. */
5819 }
5826 /* We shouldn't ever see these dynamic relocs in relocatable
5827 files. */
5828 /* Fall thru */
5838 /* These ones haven't been implemented yet. */
5848 }
5850 /* Do any further special processing. */
5852 {
5862 /* It's just possible that this symbol is a weak symbol
5863 that's not actually defined anywhere. In that case,
5864 'sec' would be NULL, and we should leave the symbol
5865 alone (it will be set to zero elsewhere in the link). */
5867 /* Add 0x10000 if sign bit in 0:15 is set. */
5883 {
5891 }
5903 branch_check:
5904 /* If the branch is out of reach, then redirect the
5905 call to the local stub for this function. */
5906 from = (offset
5912 {
5913 /* Munge up the value and addend so that we call the stub
5914 rather than the procedure directly. */
5919 }
5921 }
5923 /* Dynamic relocs are not propagated for SEC_DEBUGGING sections
5924 because such sections are not SEC_ALLOC and thus ld.so will
5925 not process them. */
5929 {
5937 }
5940 input_bfd,
5941 input_section,
5942 contents,
5943 offset,
5944 relocation,
5945 addend);
5948 {
5952 {
5955 {
5956 /* Assume this is a call protected by other code that
5957 detects the symbol is undefined. If this is the case,
5958 we can safely ignore the overflow. If not, the
5959 program is hosed anyway, and a little warning isn't
5960 going to help. */
5963 }
5966 }
5967 else
5968 {
5976 }
5979 {
5986 }
5987 else
5988 {
5995 }
5996 }
5997 }
6000 }
6002 /* Finish up dynamic symbol handling. We set the contents of various
6003 dynamic sections here. */
6005 static boolean
6011 {
6020 {
6021 Elf_Internal_Rela rela;
6024 /* This symbol has an entry in the procedure linkage table. Set
6025 it up. */
6032 /* Create a JMP_SLOT reloc to inform the dynamic linker to
6033 fill in the PLT entry. */
6044 }
6047 {
6048 Elf_Internal_Rela rela;
6051 /* This symbol has an entry in the global offset table. Set it
6052 up. */
6061 /* If this is a static link, or it is a -Bsymbolic link and the
6062 symbol is defined locally or was forced to be local because
6063 of a version file, we just want to emit a RELATIVE reloc.
6064 The entry in the global offset table will already have been
6065 initialized in the relocate_section function. */
6071 {
6077 }
6078 else
6079 {
6085 }
6090 }
6093 {
6094 Elf_Internal_Rela rela;
6097 /* This symbol needs a copy reloc. Set it up. */
6113 }
6115 /* Mark some specially defined symbols as absolute. */
6120 }
6122 /* Used to decide how to sort relocs in an optimal manner for the
6123 dynamic linker, before writing them out. */
6125 static enum elf_reloc_type_class
6128 {
6133 {
6142 }
6143 }
6145 /* Finish up the dynamic sections. */
6147 static boolean
6151 {
6161 {
6170 {
6171 Elf_Internal_Dyn dyn;
6177 {
6213 /* Don't count procedure linkage table relocs in the
6214 overall reloc count. */
6218 }
6221 }
6222 }
6225 {
6226 /* Fill in the first entry in the global offset table.
6227 We use it to hold the link-time TOCbase. */
6232 /* Set .got entry size. */
6234 }
6237 {
6238 /* Set .plt entry size. */
6241 }
6244 }
6246 #define TARGET_LITTLE_SYM bfd_elf64_powerpcle_vec
6248 #define TARGET_BIG_SYM bfd_elf64_powerpc_vec
6250 #define ELF_ARCH bfd_arch_powerpc
6251 #define ELF_MACHINE_CODE EM_PPC64
6252 #define ELF_MAXPAGESIZE 0x10000
6253 #define elf_info_to_howto ppc64_elf_info_to_howto
6255 #ifdef EM_CYGNUS_POWERPC
6256 #define ELF_MACHINE_ALT1 EM_CYGNUS_POWERPC
6257 #endif
6259 #ifdef EM_PPC_OLD
6260 #define ELF_MACHINE_ALT2 EM_PPC_OLD
6261 #endif
6263 #define elf_backend_want_got_sym 0
6264 #define elf_backend_want_plt_sym 0
6265 #define elf_backend_plt_alignment 3
6266 #define elf_backend_plt_not_loaded 1
6267 #define elf_backend_got_symbol_offset 0
6268 #define elf_backend_got_header_size 8
6269 #define elf_backend_plt_header_size PLT_INITIAL_ENTRY_SIZE
6270 #define elf_backend_can_gc_sections 1
6271 #define elf_backend_can_refcount 1
6272 #define elf_backend_rela_normal 1
6274 #define bfd_elf64_bfd_reloc_type_lookup ppc64_elf_reloc_type_lookup
6275 #define bfd_elf64_bfd_merge_private_bfd_data ppc64_elf_merge_private_bfd_data
6276 #define bfd_elf64_bfd_link_hash_table_create ppc64_elf_link_hash_table_create
6277 #define bfd_elf64_bfd_link_hash_table_free ppc64_elf_link_hash_table_free
6279 #define elf_backend_object_p ppc64_elf_object_p
6280 #define elf_backend_create_dynamic_sections ppc64_elf_create_dynamic_sections
6281 #define elf_backend_copy_indirect_symbol ppc64_elf_copy_indirect_symbol
6282 #define elf_backend_check_relocs ppc64_elf_check_relocs
6283 #define elf_backend_gc_mark_hook ppc64_elf_gc_mark_hook
6284 #define elf_backend_gc_sweep_hook ppc64_elf_gc_sweep_hook
6285 #define elf_backend_adjust_dynamic_symbol ppc64_elf_adjust_dynamic_symbol
6286 #define elf_backend_hide_symbol ppc64_elf_hide_symbol
6287 #define elf_backend_always_size_sections ppc64_elf_func_desc_adjust
6288 #define elf_backend_size_dynamic_sections ppc64_elf_size_dynamic_sections
6289 #define elf_backend_relocate_section ppc64_elf_relocate_section
6290 #define elf_backend_finish_dynamic_symbol ppc64_elf_finish_dynamic_symbol
6291 #define elf_backend_reloc_type_class ppc64_elf_reloc_type_class
6292 #define elf_backend_finish_dynamic_sections ppc64_elf_finish_dynamic_sections