| blob | b3d8308fb072527ca0b029fe60b069b569d609ad |
1 /* PowerPC-specific support for 32-bit ELF
2 Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
3 2004, 2005 Free Software Foundation, Inc.
4 Written by Ian Lance Taylor, Cygnus Support.
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
20 Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
21 Boston, MA 02110-1301, USA. */
23 /* This file is based on a preliminary PowerPC ELF ABI. The
24 information may not match the final PowerPC ELF ABI. It includes
25 suggestions from the in-progress Embedded PowerPC ABI, and that
26 information may also not match. */
37 /* RELA relocations are used here. */
39 static bfd_reloc_status_type ppc_elf_addr16_ha_reloc
41 static bfd_reloc_status_type ppc_elf_unhandled_reloc
44 /* Branch prediction bit for branch taken relocs. */
45 #define BRANCH_PREDICT_BIT 0x200000
46 /* Mask to set RA in memory instructions. */
47 #define RA_REGISTER_MASK 0x001f0000
48 /* Value to shift register by to insert RA. */
49 #define RA_REGISTER_SHIFT 16
51 /* The name of the dynamic interpreter. This is put in the .interp
52 section. */
55 /* For old-style PLT. */
56 /* The number of single-slot PLT entries (the rest use two slots). */
57 #define PLT_NUM_SINGLE_ENTRIES 8192
59 /* For new-style .glink and .plt. */
60 #define GLINK_PLTRESOLVE 16*4
61 #define GLINK_ENTRY_SIZE 4*4
63 /* VxWorks uses its own plt layout, filled in by the static linker. */
65 /* The standard VxWorks PLT entry. */
66 #define VXWORKS_PLT_ENTRY_SIZE 32
67 static const bfd_vma ppc_elf_vxworks_plt_entry
69 {
78 };
79 static const bfd_vma ppc_elf_vxworks_pic_plt_entry
81 {
90 };
92 /* The initial VxWorks PLT entry. */
93 #define VXWORKS_PLT_INITIAL_ENTRY_SIZE 32
94 static const bfd_vma ppc_elf_vxworks_plt0_entry
96 {
105 };
106 static const bfd_vma ppc_elf_vxworks_pic_plt0_entry
108 {
117 };
119 /* For executables, we have some additional relocations in
120 .rela.plt.unloaded, for the kernel loader. */
122 /* The number of non-JMP_SLOT relocations per PLT0 slot. */
123 #define VXWORKS_PLT_NON_JMP_SLOT_RELOCS 3
124 /* The number of relocations in the PLTResolve slot. */
125 #define VXWORKS_PLTRESOLVE_RELOCS 2
126 /* The number of relocations in the PLTResolve slot when when creating
127 a shared library. */
128 #define VXWORKS_PLTRESOLVE_RELOCS_SHLIB 0
130 /* Some instructions. */
131 #define ADDIS_11_11 0x3d6b0000
132 #define ADDIS_11_30 0x3d7e0000
133 #define ADDIS_12_12 0x3d8c0000
134 #define ADDI_11_11 0x396b0000
135 #define ADD_0_11_11 0x7c0b5a14
136 #define ADD_11_0_11 0x7d605a14
137 #define B 0x48000000
138 #define BCL_20_31 0x429f0005
139 #define BCTR 0x4e800420
140 #define LIS_11 0x3d600000
141 #define LIS_12 0x3d800000
142 #define LWZU_0_12 0x840c0000
143 #define LWZ_0_12 0x800c0000
144 #define LWZ_11_11 0x816b0000
145 #define LWZ_11_30 0x817e0000
146 #define LWZ_12_12 0x818c0000
147 #define MFLR_0 0x7c0802a6
148 #define MFLR_12 0x7d8802a6
149 #define MTCTR_0 0x7c0903a6
150 #define MTCTR_11 0x7d6903a6
151 #define MTLR_0 0x7c0803a6
152 #define NOP 0x60000000
153 #define SUB_11_11_12 0x7d6c5850
155 /* Offset of tp and dtp pointers from start of TLS block. */
156 #define TP_OFFSET 0x7000
157 #define DTP_OFFSET 0x8000
158 \f
162 /* This reloc does nothing. */
177 /* A standard 32 bit relocation. */
192 /* An absolute 26 bit branch; the lower two bits must be zero.
193 FIXME: we don't check that, we just clear them. */
208 /* A standard 16 bit relocation. */
223 /* A 16 bit relocation without overflow. */
238 /* The high order 16 bits of an address. */
253 /* The high order 16 bits of an address, plus 1 if the contents of
254 the low 16 bits, treated as a signed number, is negative. */
269 /* An absolute 16 bit branch; the lower two bits must be zero.
270 FIXME: we don't check that, we just clear them. */
285 /* An absolute 16 bit branch, for which bit 10 should be set to
286 indicate that the branch is expected to be taken. The lower two
287 bits must be zero. */
302 /* An absolute 16 bit branch, for which bit 10 should be set to
303 indicate that the branch is not expected to be taken. The lower
304 two bits must be zero. */
319 /* A relative 26 bit branch; the lower two bits must be zero. */
334 /* A relative 16 bit branch; the lower two bits must be zero. */
349 /* A relative 16 bit branch. Bit 10 should be set to indicate that
350 the branch is expected to be taken. The lower two bits must be
351 zero. */
366 /* A relative 16 bit branch. Bit 10 should be set to indicate that
367 the branch is not expected to be taken. The lower two bits must
368 be zero. */
383 /* Like R_PPC_ADDR16, but referring to the GOT table entry for the
384 symbol. */
399 /* Like R_PPC_ADDR16_LO, but referring to the GOT table entry for
400 the symbol. */
415 /* Like R_PPC_ADDR16_HI, but referring to the GOT table entry for
416 the symbol. */
431 /* Like R_PPC_ADDR16_HA, but referring to the GOT table entry for
432 the symbol. */
447 /* Like R_PPC_REL24, but referring to the procedure linkage table
448 entry for the symbol. */
463 /* This is used only by the dynamic linker. The symbol should exist
464 both in the object being run and in some shared library. The
465 dynamic linker copies the data addressed by the symbol from the
466 shared library into the object, because the object being
467 run has to have the data at some particular address. */
482 /* Like R_PPC_ADDR32, but used when setting global offset table
483 entries. */
498 /* Marks a procedure linkage table entry for a symbol. */
513 /* Used only by the dynamic linker. When the object is run, this
514 longword is set to the load address of the object, plus the
515 addend. */
530 /* Like R_PPC_REL24, but uses the value of the symbol within the
531 object rather than the final value. Normally used for
532 _GLOBAL_OFFSET_TABLE_. */
547 /* Like R_PPC_ADDR32, but may be unaligned. */
562 /* Like R_PPC_ADDR16, but may be unaligned. */
577 /* 32-bit PC relative */
592 /* 32-bit relocation to the symbol's procedure linkage table.
593 FIXME: not supported. */
608 /* 32-bit PC relative relocation to the symbol's procedure linkage table.
609 FIXME: not supported. */
624 /* Like R_PPC_ADDR16_LO, but referring to the PLT table entry for
625 the symbol. */
640 /* Like R_PPC_ADDR16_HI, but referring to the PLT table entry for
641 the symbol. */
656 /* Like R_PPC_ADDR16_HA, but referring to the PLT table entry for
657 the symbol. */
672 /* A sign-extended 16 bit value relative to _SDA_BASE_, for use with
673 small data items. */
688 /* 16-bit section relative relocation. */
703 /* 16-bit lower half section relative relocation. */
718 /* 16-bit upper half section relative relocation. */
733 /* 16-bit upper half adjusted section relative relocation. */
748 /* Marker reloc for TLS. */
763 /* Computes the load module index of the load module that contains the
764 definition of its TLS sym. */
779 /* Computes a dtv-relative displacement, the difference between the value
780 of sym+add and the base address of the thread-local storage block that
781 contains the definition of sym, minus 0x8000. */
796 /* A 16 bit dtprel reloc. */
811 /* Like DTPREL16, but no overflow. */
826 /* Like DTPREL16_LO, but next higher group of 16 bits. */
841 /* Like DTPREL16_HI, but adjust for low 16 bits. */
856 /* Computes a tp-relative displacement, the difference between the value of
857 sym+add and the value of the thread pointer (r13). */
872 /* A 16 bit tprel reloc. */
887 /* Like TPREL16, but no overflow. */
902 /* Like TPREL16_LO, but next higher group of 16 bits. */
917 /* Like TPREL16_HI, but adjust for low 16 bits. */
932 /* Allocates two contiguous entries in the GOT to hold a tls_index structure,
933 with values (sym+add)@dtpmod and (sym+add)@dtprel, and computes the offset
934 to the first entry. */
949 /* Like GOT_TLSGD16, but no overflow. */
964 /* Like GOT_TLSGD16_LO, but next higher group of 16 bits. */
979 /* Like GOT_TLSGD16_HI, but adjust for low 16 bits. */
994 /* Allocates two contiguous entries in the GOT to hold a tls_index structure,
995 with values (sym+add)@dtpmod and zero, and computes the offset to the
996 first entry. */
1011 /* Like GOT_TLSLD16, but no overflow. */
1026 /* Like GOT_TLSLD16_LO, but next higher group of 16 bits. */
1041 /* Like GOT_TLSLD16_HI, but adjust for low 16 bits. */
1056 /* Allocates an entry in the GOT with value (sym+add)@dtprel, and computes
1057 the offset to the entry. */
1072 /* Like GOT_DTPREL16, but no overflow. */
1087 /* Like GOT_DTPREL16_LO, but next higher group of 16 bits. */
1102 /* Like GOT_DTPREL16_HI, but adjust for low 16 bits. */
1117 /* Allocates an entry in the GOT with value (sym+add)@tprel, and computes the
1118 offset to the entry. */
1133 /* Like GOT_TPREL16, but no overflow. */
1148 /* Like GOT_TPREL16_LO, but next higher group of 16 bits. */
1163 /* Like GOT_TPREL16_HI, but adjust for low 16 bits. */
1178 /* The remaining relocs are from the Embedded ELF ABI, and are not
1179 in the SVR4 ELF ABI. */
1181 /* 32 bit value resulting from the addend minus the symbol. */
1196 /* 16 bit value resulting from the addend minus the symbol. */
1211 /* 16 bit value resulting from the addend minus the symbol. */
1226 /* The high order 16 bits of the addend minus the symbol. */
1241 /* The high order 16 bits of the result of the addend minus the address,
1242 plus 1 if the contents of the low 16 bits, treated as a signed number,
1243 is negative. */
1258 /* 16 bit value resulting from allocating a 4 byte word to hold an
1259 address in the .sdata section, and returning the offset from
1260 _SDA_BASE_ for that relocation. */
1275 /* 16 bit value resulting from allocating a 4 byte word to hold an
1276 address in the .sdata2 section, and returning the offset from
1277 _SDA2_BASE_ for that relocation. */
1292 /* A sign-extended 16 bit value relative to _SDA2_BASE_, for use with
1293 small data items. */
1308 /* Relocate against either _SDA_BASE_ or _SDA2_BASE_, filling in the 16 bit
1309 signed offset from the appropriate base, and filling in the register
1310 field with the appropriate register (0, 2, or 13). */
1325 /* Relocation not handled: R_PPC_EMB_MRKREF */
1326 /* Relocation not handled: R_PPC_EMB_RELSEC16 */
1327 /* Relocation not handled: R_PPC_EMB_RELST_LO */
1328 /* Relocation not handled: R_PPC_EMB_RELST_HI */
1329 /* Relocation not handled: R_PPC_EMB_RELST_HA */
1330 /* Relocation not handled: R_PPC_EMB_BIT_FLD */
1332 /* PC relative relocation against either _SDA_BASE_ or _SDA2_BASE_, filling
1333 in the 16 bit signed offset from the appropriate base, and filling in the
1334 register field with the appropriate register (0, 2, or 13). */
1349 /* A 16 bit relative relocation. */
1364 /* A 16 bit relative relocation without overflow. */
1379 /* The high order 16 bits of a relative address. */
1394 /* The high order 16 bits of a relative address, plus 1 if the contents of
1395 the low 16 bits, treated as a signed number, is negative. */
1410 /* GNU extension to record C++ vtable hierarchy. */
1425 /* GNU extension to record C++ vtable member usage. */
1440 /* Phony reloc to handle AIX style TOC entries. */
1454 };
1455 \f
1456 /* Initialize the ppc_elf_howto_table, so that linear accesses can be done. */
1458 static void
1460 {
1465 i++)
1466 {
1472 }
1473 }
1477 bfd_reloc_code_real_type code)
1478 {
1481 /* Initialize howto table if not already done. */
1486 {
1575 }
1578 };
1580 /* Set the howto pointer for a PowerPC ELF reloc. */
1582 static void
1586 {
1587 /* Initialize howto table if not already done. */
1593 }
1595 /* Handle the R_PPC_ADDR16_HA and R_PPC_REL16_HA relocs. */
1597 static bfd_reloc_status_type
1605 {
1606 bfd_vma relocation;
1609 {
1612 }
1619 else
1631 }
1633 static bfd_reloc_status_type
1641 {
1642 /* If this is a relocatable link (output_bfd test tells us), just
1643 call the generic function. Any adjustment will be done at final
1644 link time. */
1650 {
1655 }
1657 }
1658 \f
1659 /* Sections created by the linker. */
1662 {
1663 /* Pointer to the bfd section. */
1665 /* Section name. */
1667 /* Associated bss section name. */
1669 /* Associated symbol name. */
1671 /* Associated symbol. */
1675 /* Linked list of allocated pointer entries. This hangs off of the
1676 symbol lists, and provides allows us to return different pointers,
1677 based on different addend's. */
1680 {
1681 /* next allocated pointer for this symbol */
1683 /* offset of pointer from beginning of section */
1684 bfd_vma offset;
1685 /* addend used */
1686 bfd_vma addend;
1687 /* which linker section this is */
1691 struct ppc_elf_obj_tdata
1692 {
1695 /* A mapping from local symbols to offsets into the various linker
1696 sections added. This is index by the symbol index. */
1698 };
1700 #define ppc_elf_tdata(bfd) \
1701 ((struct ppc_elf_obj_tdata *) (bfd)->tdata.any)
1703 #define elf_local_ptr_offsets(bfd) \
1704 (ppc_elf_tdata (bfd)->linker_section_pointers)
1706 /* Override the generic function because we store some extras. */
1708 static bfd_boolean
1710 {
1716 }
1718 /* Fix bad default arch selected for a 32 bit input bfd when the
1719 default is 64 bit. */
1721 static bfd_boolean
1723 {
1725 {
1729 {
1730 /* Relies on arch after 64 bit default being 32 bit default. */
1733 }
1734 }
1736 }
1738 /* Function to set whether a module needs the -mrelocatable bit set. */
1740 static bfd_boolean
1742 {
1749 }
1751 /* Support for core dump NOTE sections. */
1753 static bfd_boolean
1755 {
1760 {
1765 /* pr_cursig */
1768 /* pr_pid */
1771 /* pr_reg */
1776 }
1778 /* Make a ".reg/999" section. */
1781 }
1783 static bfd_boolean
1785 {
1787 {
1796 }
1798 /* Note that for some reason, a spurious space is tacked
1799 onto the end of the args in some (at least one anyway)
1800 implementations, so strip it off if it exists. */
1802 {
1808 }
1811 }
1813 /* Return address for Ith PLT stub in section PLT, for relocation REL
1814 or (bfd_vma) -1 if it should not be included. */
1816 static bfd_vma
1820 {
1822 }
1824 /* Handle a PowerPC specific section when reading an object file. This
1825 is called when bfd_section_from_shdr finds a section with an unknown
1826 type. */
1828 static bfd_boolean
1833 {
1835 flagword flags;
1850 }
1852 /* Set up any other section flags and such that may be necessary. */
1854 static bfd_boolean
1858 {
1866 }
1868 /* If we have .sbss2 or .PPC.EMB.sbss0 output sections, we
1869 need to bump up the number of section headers. */
1871 static int
1873 {
1886 }
1888 /* Add extra PPC sections -- Note, for now, make .sbss2 and
1889 .PPC.EMB.sbss0 a normal section, and not a bss section so
1890 that the linker doesn't crater when trying to make more than
1891 2 sections. */
1894 {
1905 };
1907 /* This is what we want for new plt/got. */
1913 {
1916 /* See if this is one of the special sections. */
1923 {
1927 }
1930 }
1931 \f
1932 /* Very simple linked list structure for recording apuinfo values. */
1934 {
1937 }
1938 apuinfo_list;
1943 static void
1945 {
1947 }
1949 static void
1951 {
1955 {
1959 }
1968 }
1970 static unsigned
1972 {
1977 entry;
1982 }
1986 {
1992 ;
1995 }
1997 static void
1999 {
2003 {
2007 }
2010 }
2015 /* Scan the input BFDs and create a linked list of
2016 the APUinfo values that will need to be emitted. */
2018 static void
2020 {
2025 bfd_size_type output_section_size;
2035 /* Scan the input bfds, looking for apuinfo sections. */
2040 {
2043 {
2046 }
2047 }
2049 /* We need at least one input sections
2050 in order to make merging worthwhile. */
2054 /* Just make sure that the output section exists as well. */
2059 /* Allocate a buffer for the contents of the input sections. */
2067 /* Read in the input sections contents. */
2069 {
2079 {
2082 }
2086 {
2089 }
2091 /* Process the contents of the section. */
2095 /* Verify the contents of the header. Note - we have to
2096 extract the values this way in order to allow for a
2097 host whose endian-ness is different from the target. */
2109 /* Get the number of bytes used for apuinfo entries. */
2114 /* Make sure that we do not run off the end of the section. */
2118 /* Scan the apuinfo section, building a list of apuinfo numbers. */
2122 /* Update the offset. */
2124 }
2128 /* Compute the size of the output section. */
2138 fail:
2143 }
2145 /* Prevent the output section from accumulating the input sections'
2146 contents. We have already stored this in our linked list structure. */
2148 static bfd_boolean
2152 {
2155 }
2157 /* Finally we can generate the output section. */
2159 static void
2161 {
2166 bfd_size_type length;
2181 {
2185 }
2187 /* Create the apuinfo header. */
2196 {
2199 }
2210 }
2211 \f
2212 /* The following functions are specific to the ELF linker, while
2213 functions above are used generally. They appear in this file more
2214 or less in the order in which they are called. eg.
2215 ppc_elf_check_relocs is called early in the link process,
2216 ppc_elf_finish_dynamic_sections is one of the last functions
2217 called. */
2219 /* The PPC linker needs to keep track of the number of relocs that it
2220 decides to copy as dynamic relocs in check_relocs for each symbol.
2221 This is so that it can later discard them if they are found to be
2222 unnecessary. We store the information in a field extending the
2223 regular ELF linker hash table. */
2225 struct ppc_elf_dyn_relocs
2226 {
2229 /* The input section of the reloc. */
2232 /* Total number of relocs copied for the input section. */
2233 bfd_size_type count;
2235 /* Number of pc-relative relocs copied for the input section. */
2236 bfd_size_type pc_count;
2237 };
2239 /* Track PLT entries needed for a given symbol. We might need more
2240 than one glink entry per symbol. */
2241 struct plt_entry
2242 {
2245 /* -fPIC uses multiple GOT sections, one per file, called ".got2".
2246 This field stores the offset into .got2 used to initialise the
2247 GOT pointer reg. It will always be at least 32768 (and for
2248 current gcc this is the only offset used). */
2249 bfd_vma addend;
2251 /* The .got2 section. */
2254 /* PLT refcount or offset. */
2255 union
2256 {
2257 bfd_signed_vma refcount;
2258 bfd_vma offset;
2261 /* .glink stub offset. */
2262 bfd_vma glink_offset;
2263 };
2265 /* Of those relocs that might be copied as dynamic relocs, this macro
2266 selects those that must be copied when linking a shared library,
2267 even when the symbol is local. */
2269 #define MUST_BE_DYN_RELOC(RTYPE) \
2270 ((RTYPE) != R_PPC_REL24 \
2271 && (RTYPE) != R_PPC_REL14 \
2272 && (RTYPE) != R_PPC_REL14_BRTAKEN \
2273 && (RTYPE) != R_PPC_REL14_BRNTAKEN \
2274 && (RTYPE) != R_PPC_REL32)
2276 /* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid
2277 copying dynamic variables from a shared lib into an app's dynbss
2278 section, and instead use a dynamic relocation to point into the
2279 shared lib. */
2280 #define ELIMINATE_COPY_RELOCS 1
2282 /* PPC ELF linker hash entry. */
2284 struct ppc_elf_link_hash_entry
2285 {
2288 /* If this symbol is used in the linker created sections, the processor
2289 specific backend uses this field to map the field into the offset
2290 from the beginning of the section. */
2293 /* Track dynamic relocs copied for this symbol. */
2296 /* Contexts in which symbol is used in the GOT (or TOC).
2297 TLS_GD .. TLS_TLS bits are or'd into the mask as the
2298 corresponding relocs are encountered during check_relocs.
2299 tls_optimize clears TLS_GD .. TLS_TPREL when optimizing to
2300 indicate the corresponding GOT entry type is not needed. */
2309 /* Nonzero if we have seen a small data relocation referring to this
2310 symbol. */
2312 };
2314 #define ppc_elf_hash_entry(ent) ((struct ppc_elf_link_hash_entry *) (ent))
2317 PLT_UNSET,
2318 PLT_OLD,
2319 PLT_NEW,
2320 PLT_VXWORKS
2321 };
2323 /* PPC ELF linker hash table. */
2325 struct ppc_elf_link_hash_table
2326 {
2329 /* Short-cuts to get to dynamic linker sections. */
2342 /* Shortcut to .__tls_get_addr. */
2345 /* TLS local dynamic got entry handling. */
2347 bfd_signed_vma refcount;
2348 bfd_vma offset;
2351 /* Offset of PltResolve function in glink. */
2352 bfd_vma glink_pltresolve;
2354 /* Size of reserved GOT entries. */
2356 /* Non-zero if allocating the header left a gap. */
2359 /* The type of PLT we have chosen to use. */
2362 /* Whether we can use the new PLT layout. */
2365 /* Set if we should emit symbols for stubs. */
2368 /* Small local sym to section mapping cache. */
2371 /* The (unloaded but important) .rela.plt.unloaded on VxWorks. */
2374 /* The .got.plt section (VxWorks only)*/
2377 /* True if the target system is VxWorks. */
2380 /* The size of PLT entries. */
2382 /* The distance between adjacent PLT slots. */
2384 /* The size of the first PLT entry. */
2386 };
2388 /* Get the PPC ELF linker hash table from a link_info structure. */
2390 #define ppc_elf_hash_table(p) \
2391 ((struct ppc_elf_link_hash_table *) (p)->hash)
2393 /* Create an entry in a PPC ELF linker hash table. */
2399 {
2400 /* Allocate the structure if it has not already been allocated by a
2401 subclass. */
2403 {
2408 }
2410 /* Call the allocation method of the superclass. */
2413 {
2417 }
2420 }
2422 /* Create a PPC ELF linker hash table. */
2426 {
2434 ppc_elf_link_hash_newfunc))
2435 {
2438 }
2460 }
2462 /* Create .got and the related sections. */
2464 static bfd_boolean
2466 {
2469 flagword flags;
2480 {
2484 }
2485 else
2486 {
2487 /* The powerpc .got has a blrl instruction in it. Mark it
2488 executable. */
2493 }
2503 }
2505 /* We have to create .dynsbss and .rela.sbss here so that they get mapped
2506 to output sections (just like _bfd_elf_create_dynamic_sections has
2507 to create .dynbss and .rela.bss). */
2509 static bfd_boolean
2511 {
2514 flagword flags;
2542 {
2549 }
2562 /* The VxWorks PLT is a loaded section with contents. */
2565 }
2567 /* Copy the extra info we tack onto an elf_link_hash_entry. */
2569 static void
2573 {
2580 {
2582 {
2586 /* Add reloc counts against the indirect sym to the direct sym
2587 list. Merge any entries against the same section. */
2589 {
2594 {
2599 }
2602 }
2604 }
2608 }
2613 /* If called to transfer flags for a weakdef during processing
2614 of elf_adjust_dynamic_symbol, don't copy non_got_ref.
2615 We clear it ourselves for ELIMINATE_COPY_RELOCS. */
2626 /* If we were called to copy over info for a weak sym, that's all. */
2630 /* Copy over the GOT refcount entries that we may have already seen to
2631 the symbol which just became indirect. */
2635 /* And plt entries. */
2637 {
2639 {
2644 {
2649 {
2653 }
2656 }
2658 }
2662 }
2665 {
2673 }
2674 }
2676 /* Return 1 if target is one of ours. */
2678 static bfd_boolean
2680 {
2688 }
2690 /* Hook called by the linker routine which adds symbols from an object
2691 file. We use it to put .comm items in .sbss, and not .bss. */
2693 static bfd_boolean
2701 {
2706 {
2707 /* Common symbols less than or equal to -G nn bytes are automatically
2708 put into .sbss. */
2713 {
2721 flags);
2724 }
2728 }
2731 }
2732 \f
2733 static bfd_boolean
2736 {
2745 }
2747 /* Create a special linker section. */
2749 static bfd_boolean
2752 flagword flags,
2754 {
2761 /* Record the first bfd that needs the special sections. */
2767 flags);
2774 }
2776 /* Find a linker generated pointer with a given addend and type. */
2779 elf_find_pointer_linker_section
2781 bfd_vma addend,
2783 {
2789 }
2791 /* Allocate a pointer to live in a linker created section. */
2793 static bfd_boolean
2798 {
2802 bfd_size_type amt;
2806 /* Is this a global symbol? */
2808 {
2811 /* Has this symbol already been allocated? If so, our work is done. */
2815 lsect))
2819 }
2820 else
2821 {
2822 /* Allocation of a pointer to a local symbol. */
2825 /* Allocate a table to hold the local symbols if first time. */
2827 {
2838 }
2840 /* Has this symbol already been allocated? If so, our work is done. */
2843 lsect))
2847 }
2849 /* Allocate space for a pointer in the linker section, and allocate
2850 a new pointer record from internal memory. */
2866 #ifdef DEBUG
2871 #endif
2874 }
2876 static bfd_boolean
2881 {
2886 {
2894 }
2900 }
2902 static bfd_boolean
2905 {
2914 {
2924 }
2927 }
2931 {
2940 }
2942 static void
2944 {
2947 abfd,
2950 }
2952 /* Look through the relocs for a section during the first phase, and
2953 allocate space in the global offset table or procedure linkage
2954 table. */
2956 static bfd_boolean
2961 {
2972 /* Don't do anything special with non-loaded, non-alloced sections.
2973 In particular, any relocs in such sections should not affect GOT
2974 and PLT reference counting (ie. we don't allow them to create GOT
2975 or PLT entries), there's no possibility or desire to optimize TLS
2976 relocs, and there's not much point in propagating relocs to shared
2977 libs that the dynamic linker won't relocate. */
2981 #ifdef DEBUG
2984 #endif
2986 /* Initialize howto table if not already done. */
2998 {
3007 else
3008 {
3013 }
3015 /* If a relocation refers to _GLOBAL_OFFSET_TABLE_, create the .got.
3016 This shows up in particular in an R_PPC_ADDR32 in the eabi
3017 startup code. */
3021 {
3027 }
3031 {
3061 dogottls:
3063 /* Fall thru */
3065 /* GOT16 relocations */
3070 /* This symbol requires a global offset table entry. */
3072 {
3077 }
3079 {
3082 }
3083 else
3084 /* This is a global offset table entry for a local symbol. */
3089 /* Indirect .sdata relocation. */
3092 {
3095 }
3104 {
3107 }
3110 /* Indirect .sdata2 relocation. */
3113 {
3116 }
3125 {
3128 }
3133 {
3136 }
3141 {
3144 }
3149 {
3152 }
3157 {
3160 }
3166 {
3169 }
3177 {
3180 }
3189 {
3192 }
3203 #ifdef DEBUG
3205 #endif
3206 /* This symbol requires a procedure linkage table entry. We
3207 actually build the entry in finish_dynamic_symbol,
3208 because this might be a case of linking PIC code without
3209 linking in any dynamic objects, in which case we don't
3210 need to generate a procedure linkage table after all. */
3213 {
3214 /* It does not make sense to have a procedure linkage
3215 table entry for a local symbol. */
3218 abfd,
3219 sec,
3224 }
3225 else
3226 {
3232 }
3235 /* The following relocations don't need to propagate the
3236 relocation if linking a shared object since they are
3237 section relative. */
3256 /* These are just markers. */
3263 /* These should only appear in dynamic objects. */
3270 /* These aren't handled yet. We'll report an error later. */
3279 /* This refers only to functions defined in the shared library. */
3285 /* This relocation describes the C++ object vtable hierarchy.
3286 Reconstruct it for later use during GC. */
3292 /* This relocation describes which C++ vtable entries are actually
3293 used. Record for later use during GC. */
3299 /* We shouldn't really be seeing these. */
3305 /* Nor these. */
3324 {
3325 /* Old -fPIC gcc code has .long LCTOC1-LCFx just before
3326 the start of a function, which assembles to a REL32
3327 reference to .got2. If we detect one of these, then
3328 force the old PLT layout because the linker cannot
3329 reliably deduce the GOT pointer value needed for
3330 PLT call stubs. */
3334 r_symndx);
3337 }
3338 /* fall through */
3347 {
3350 }
3351 /* fall through */
3365 {
3366 /* We may need a plt entry if the symbol turns out to be
3367 a function defined in a dynamic object. */
3371 /* We may need a copy reloc too. */
3373 }
3375 dodyn:
3376 /* If we are creating a shared library, and this is a reloc
3377 against a global symbol, or a non PC relative reloc
3378 against a local symbol, then we need to copy the reloc
3379 into the shared library. However, if we are linking with
3380 -Bsymbolic, we do not need to copy a reloc against a
3381 global symbol which is defined in an object we are
3382 including in the link (i.e., DEF_REGULAR is set). At
3383 this point we have not seen all the input files, so it is
3384 possible that DEF_REGULAR is not set now but will be set
3385 later (it is never cleared). In case of a weak definition,
3386 DEF_REGULAR may be cleared later by a strong definition in
3387 a shared library. We account for that possibility below by
3388 storing information in the dyn_relocs field of the hash
3389 table entry. A similar situation occurs when creating
3390 shared libraries and symbol visibility changes render the
3391 symbol local.
3393 If on the other hand, we are creating an executable, we
3394 may need to keep relocations for symbols satisfied by a
3395 dynamic library if we manage to avoid copy relocs for the
3396 symbol. */
3403 || (ELIMINATE_COPY_RELOCS
3408 {
3412 #ifdef DEBUG
3414 "ppc_elf_check_relocs needs to "
3418 #endif
3420 {
3423 name = (bfd_elf_string_from_elf_section
3438 {
3439 flagword flags;
3445 name,
3446 flags);
3451 }
3453 }
3455 /* If this is a global symbol, we count the number of
3456 relocations we need for this symbol. */
3458 {
3460 }
3461 else
3462 {
3463 /* Track dynamic relocs needed for local syms too.
3464 We really need local syms available to do this
3465 easily. Oh well. */
3477 }
3481 {
3490 }
3495 }
3498 }
3499 }
3502 }
3503 \f
3504 /* Merge backend specific data from an object file to the output
3505 object file when linking. */
3507 static bfd_boolean
3509 {
3510 flagword old_flags;
3511 flagword new_flags;
3512 bfd_boolean error;
3518 /* Check if we have the same endianess. */
3525 {
3526 /* First call, no flags set. */
3529 }
3531 /* Compatible flags are ok. */
3533 ;
3535 /* Incompatible flags. */
3536 else
3537 {
3538 /* Warn about -mrelocatable mismatch. Allow -mrelocatable-lib
3539 to be linked with either. */
3543 {
3548 }
3551 {
3556 }
3558 /* The output is -mrelocatable-lib iff both the input files are. */
3562 /* The output is -mrelocatable iff it can't be -mrelocatable-lib,
3563 but each input file is either -mrelocatable or -mrelocatable-lib. */
3569 /* Do not warn about eabi vs. V.4 mismatch, just or in the bit if
3570 any module uses it. */
3576 /* Warn about any other mismatches. */
3578 {
3584 }
3587 {
3590 }
3591 }
3594 }
3595 \f
3596 /* Choose which PLT scheme to use, and set .plt flags appropriately.
3597 Returns -1 on error, 0 for old PLT, 1 for new PLT. */
3598 int
3603 {
3605 flagword flags;
3618 {
3622 /* The new PLT is a loaded section. */
3627 /* The new GOT is not executable. */
3631 }
3632 else
3633 {
3634 /* Stop an unused .glink section from affecting .text alignment. */
3638 }
3640 }
3641 \f
3642 /* Return the section that should be marked against GC for a given
3643 relocation. */
3651 {
3653 {
3655 {
3662 {
3672 }
3673 }
3674 }
3675 else
3679 }
3681 /* Update the got, plt and dynamic reloc reference counts for the
3682 section being removed. */
3684 static bfd_boolean
3689 {
3710 {
3717 {
3729 {
3730 /* Everything must go for SEC. */
3733 }
3734 }
3738 {
3744 /* Fall thru */
3763 {
3766 }
3768 {
3771 }
3781 /* Fall thru */
3804 {
3809 }
3814 }
3815 }
3817 }
3818 \f
3819 /* Set htab->tls_get_addr and call the generic ELF tls_setup function. */
3821 asection *
3823 {
3830 {
3833 }
3838 }
3840 /* Run through all the TLS relocs looking for optimization
3841 opportunities. */
3843 bfd_boolean
3846 {
3856 {
3862 {
3866 /* Read the relocations. */
3875 {
3881 bfd_boolean is_local;
3885 {
3893 }
3902 {
3907 /* These relocs should never be against a symbol
3908 defined in a shared lib. Leave them alone if
3909 that turns out to be the case. */
3915 /* LD -> LE */
3926 /* GD -> LE */
3928 else
3929 /* GD -> IE */
3941 {
3942 /* IE -> LE */
3946 }
3947 else
3957 {
3961 }
3968 }
3971 {
3973 {
3974 /* We managed to get rid of a got entry. */
3977 }
3979 }
3980 else
3981 {
3987 {
3994 {
3998 }
3999 }
4005 {
4006 /* We managed to get rid of a got entry. */
4009 }
4012 }
4016 }
4020 }
4024 {
4027 else
4029 }
4030 }
4032 }
4033 \f
4034 /* Adjust a symbol defined by a dynamic object and referenced by a
4035 regular object. The current definition is in some section of the
4036 dynamic object, but we're not including those sections. We have to
4037 change the definition to something the rest of the link can
4038 understand. */
4040 static bfd_boolean
4043 {
4048 #ifdef DEBUG
4051 #endif
4053 /* Make sure we know what is going on here. */
4062 /* Deal with function syms. */
4065 {
4066 /* Clear procedure linkage table information for any symbol that
4067 won't need a .plt entry. */
4076 {
4077 /* A PLT entry is not required/allowed when:
4079 1. We are not using ld.so; because then the PLT entry
4080 can't be set up, so we can't use one. In this case,
4081 ppc_elf_adjust_dynamic_symbol won't even be called.
4083 2. GC has rendered the entry unused.
4085 3. We know for certain that a call to this symbol
4086 will go to this object, or will remain undefined. */
4089 }
4091 }
4092 else
4095 /* If this is a weak symbol, and there is a real definition, the
4096 processor independent code will have arranged for us to see the
4097 real definition first, and we can just use the same value. */
4099 {
4107 }
4109 /* This is a reference to a symbol defined by a dynamic object which
4110 is not a function. */
4112 /* If we are creating a shared library, we must presume that the
4113 only references to the symbol are via the global offset table.
4114 For such cases we need not do anything here; the relocations will
4115 be handled correctly by relocate_section. */
4119 /* If there are no references to this symbol that do not use the
4120 GOT, we don't need to generate a copy reloc. */
4124 /* If we didn't find any dynamic relocs in read-only sections, then we'll
4125 be keeping the dynamic relocs and avoiding the copy reloc. We can't
4126 do this if there are any small data relocations. */
4129 {
4132 {
4136 }
4139 {
4142 }
4143 }
4146 {
4150 }
4152 /* We must allocate the symbol in our .dynbss section, which will
4153 become part of the .bss section of the executable. There will be
4154 an entry for this symbol in the .dynsym section. The dynamic
4155 object will contain position independent code, so all references
4156 from the dynamic object to this symbol will go through the global
4157 offset table. The dynamic linker will use the .dynsym entry to
4158 determine the address it must put in the global offset table, so
4159 both the dynamic object and the regular object will refer to the
4160 same memory location for the variable.
4162 Of course, if the symbol is referenced using SDAREL relocs, we
4163 must instead allocate it in .sbss. */
4167 else
4171 /* We must generate a R_PPC_COPY reloc to tell the dynamic linker to
4172 copy the initial value out of the dynamic object and into the
4173 runtime process image. We need to remember the offset into the
4174 .rela.bss section we are going to use. */
4176 {
4181 else
4186 }
4188 /* We need to figure out the alignment required for this symbol. I
4189 have no idea how ELF linkers handle this. */
4194 /* Apply the required alignment. */
4197 {
4200 }
4202 /* Define the symbol as being at this point in the section. */
4206 /* Increment the section size to make room for the symbol. */
4210 }
4211 \f
4212 /* Generate a symbol to mark plt call stubs. For non-PIC code the sym is
4213 xxxxxxxx.plt_call32.<callee> where xxxxxxxx is a hex number, usually 0,
4214 specifying the addend on the plt relocation. For -fpic code, the sym
4215 is xxxxxxxx.plt_pic32.<callee>, and for -fPIC
4216 xxxxxxxx.got2.plt_pic32.<callee>. */
4218 static bfd_boolean
4222 {
4231 else
4251 {
4260 }
4262 }
4264 /* Allocate NEED contiguous space in .got, and return the offset.
4265 Handles allocation of the got header when crossing 32k. */
4267 static bfd_vma
4269 {
4270 bfd_vma where;
4274 {
4277 }
4278 else
4279 {
4282 {
4285 }
4286 else
4287 {
4290 {
4293 }
4296 }
4297 }
4299 }
4301 /* Allocate space in associated reloc sections for dynamic relocs. */
4303 static bfd_boolean
4305 {
4315 /* When warning symbols are created, they **replace** the "real"
4316 entry in the hash table, thus we never get to see the real
4317 symbol in a hash traversal. So look at it now. */
4322 {
4329 {
4330 /* Make sure this symbol is output as a dynamic symbol. */
4333 {
4336 }
4340 {
4344 {
4346 {
4349 }
4354 {
4357 }
4361 {
4364 }
4370 }
4371 else
4372 {
4374 {
4375 /* If this is the first .plt entry, make room
4376 for the special first entry. */
4380 /* The PowerPC PLT is actually composed of two
4381 parts, the first part is 2 words (for a load
4382 and a jump), and then there is a remaining
4383 word available at the end. */
4390 /* If this symbol is not defined in a regular
4391 file, and we are not generating a shared
4392 library, then set the symbol to this location
4393 in the .plt. This is required to make
4394 function pointers compare as equal between
4395 the normal executable and the shared library. */
4398 {
4401 }
4403 /* Make room for this entry. */
4405 /* After the 8192nd entry, room for two entries
4406 is allocated. */
4412 }
4414 }
4416 /* We also need to make an entry in the .rela.plt section. */
4418 {
4422 {
4423 /* Allocate space for the unloaded relocations. */
4425 {
4428 {
4432 }
4437 }
4439 /* Every PLT entry has an associated GOT entry in
4440 .got.plt. */
4442 }
4444 }
4445 }
4446 else
4450 {
4453 }
4454 }
4455 }
4456 else
4457 {
4460 }
4464 {
4465 /* Make sure this symbol is output as a dynamic symbol. */
4468 {
4471 }
4475 /* If just an LD reloc, we'll just use htab->tlsld_got.offset. */
4477 else
4478 {
4479 bfd_boolean dyn;
4482 {
4491 }
4492 else
4500 {
4501 /* All the entries we allocated need relocs.
4502 Except LD only needs one. */
4506 }
4507 }
4508 }
4509 else
4515 /* In the shared -Bsymbolic case, discard space allocated for
4516 dynamic pc-relative relocs against symbols which turn out to be
4517 defined in regular objects. For the normal shared case, discard
4518 space for relocs that have become local due to symbol visibility
4519 changes. */
4522 {
4523 /* Relocs that use pc_count are those that appear on a call insn,
4524 or certain REL relocs (see MUST_BE_DYN_RELOC) that can be
4525 generated via assembly. We want calls to protected symbols to
4526 resolve directly to the function rather than going via the plt.
4527 If people want function pointer comparisons to work as expected
4528 then they should avoid writing weird assembly. */
4530 {
4534 {
4539 else
4541 }
4542 }
4544 /* Also discard relocs on undefined weak syms with non-default
4545 visibility. */
4548 {
4552 /* Make sure undefined weak symbols are output as a dynamic
4553 symbol in PIEs. */
4556 {
4559 }
4560 }
4561 }
4563 {
4564 /* For the non-shared case, discard space for relocs against
4565 symbols which turn out to need copy relocs or are not
4566 dynamic. */
4571 {
4572 /* Make sure this symbol is output as a dynamic symbol.
4573 Undefined weak syms won't yet be marked as dynamic. */
4576 {
4579 }
4581 /* If that succeeded, we know we'll be keeping all the
4582 relocs. */
4585 }
4589 keep: ;
4590 }
4592 /* Finally, allocate space. */
4594 {
4597 }
4600 }
4602 /* Find any dynamic relocs that apply to read-only sections. */
4604 static bfd_boolean
4606 {
4616 {
4622 {
4625 /* Not an error, just cut short the traversal. */
4627 }
4628 }
4630 }
4632 /* Set the sizes of the dynamic sections. */
4634 static bfd_boolean
4637 {
4640 bfd_boolean relocs;
4643 #ifdef DEBUG
4645 #endif
4651 {
4652 /* Set the contents of the .interp section to the interpreter. */
4654 {
4659 }
4660 }
4667 /* Set up .got offsets for local syms, and space for local dynamic
4668 relocs. */
4670 {
4674 bfd_size_type locsymcount;
4681 {
4688 {
4691 {
4692 /* Input section has been discarded, either because
4693 it is a copy of a linkonce section or due to
4694 linker script /DISCARD/, so we'll be discarding
4695 the relocs too. */
4696 }
4698 {
4705 }
4706 }
4707 }
4719 {
4721 {
4722 /* If just an LD reloc, we'll just use
4723 htab->tlsld_got.offset. */
4726 }
4727 else
4728 {
4731 {
4738 }
4739 else
4745 }
4746 }
4747 else
4749 }
4752 {
4756 }
4757 else
4760 /* Allocate space for global sym dynamic relocs. */
4764 {
4767 /* If we haven't allocated the header, do so now. When we get here,
4768 for old plt/got the got size will be 0 to 32764 (not allocated),
4769 or 32780 to 65536 (header allocated). For new plt/got, the
4770 corresponding ranges are 0 to 32768 and 32780 to 65536. */
4772 {
4777 }
4780 }
4783 {
4785 /* Space for the branch table. */
4787 /* Pad out to align the start of PLTresolve. */
4792 {
4799 {
4808 }
4814 {
4823 }
4824 }
4825 }
4827 /* We've now determined the sizes of the various dynamic sections.
4828 Allocate memory for them. */
4831 {
4844 {
4845 /* We'd like to strip these sections if they aren't needed, but if
4846 we've exported dynamic symbols from them we must leave them.
4847 It's too late to tell BFD to get rid of the symbols. */
4850 /* Strip this section if we don't need it; see the
4851 comment below. */
4852 }
4855 {
4856 /* Strip these too. */
4857 }
4859 {
4861 {
4862 /* Remember whether there are any relocation sections. */
4865 /* We use the reloc_count field as a counter if we need
4866 to copy relocs into the output file. */
4868 }
4869 }
4870 else
4871 {
4872 /* It's not one of our sections, so don't allocate space. */
4874 }
4877 {
4878 /* If we don't need this section, strip it from the
4879 output file. This is mostly to handle .rela.bss and
4880 .rela.plt. We must create both sections in
4881 create_dynamic_sections, because they must be created
4882 before the linker maps input sections to output
4883 sections. The linker does that before
4884 adjust_dynamic_symbol is called, and it is that
4885 function which decides whether anything needs to go
4886 into these sections. */
4889 }
4894 /* Allocate memory for the section contents. */
4898 }
4901 {
4902 /* Add some entries to the .dynamic section. We fill in the
4903 values later, in ppc_elf_finish_dynamic_sections, but we
4904 must add the entries now so that we get the correct size for
4905 the .dynamic section. The DT_DEBUG entry is filled in by the
4906 dynamic linker and used by the debugger. */
4907 #define add_dynamic_entry(TAG, VAL) \
4908 _bfd_elf_add_dynamic_entry (info, TAG, VAL)
4911 {
4914 }
4917 {
4923 }
4926 {
4929 }
4932 {
4937 }
4939 /* If any dynamic relocs apply to a read-only section, then we
4940 need a DT_TEXTREL entry. */
4943 info);
4946 {
4949 }
4950 }
4951 #undef add_dynamic_entry
4954 }
4955 \f
4956 #define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
4959 {
4968 };
4971 {
4976 };
4978 static bfd_boolean
4983 {
4984 struct one_fixup
4985 {
4988 bfd_vma toff;
4989 bfd_vma trampoff;
4990 };
4998 bfd_boolean changed;
5000 bfd_size_type trampoff;
5005 /* Nothing to do if there are no relocations, and no need to do
5006 anything with non-alloc sections. */
5013 /* Space for a branch around any trampolines. */
5018 /* Get a copy of the native relocations. */
5029 {
5041 {
5056 }
5058 /* Get the value of the symbol referred to by the reloc. */
5060 {
5061 /* A local symbol. */
5064 /* Read this BFD's local symbols. */
5066 {
5074 }
5082 else
5087 }
5088 else
5089 {
5090 /* Global symbol handling. */
5105 {
5109 {
5111 {
5114 }
5115 else
5116 {
5119 }
5120 }
5121 }
5123 ;
5126 {
5129 }
5130 else
5134 }
5136 /* If the branch and target are in the same section, you have
5137 no hope of adding stubs. We'll error out later should the
5138 branch overflow. */
5142 /* There probably isn't any reason to handle symbols in
5143 SEC_MERGE sections; SEC_MERGE doesn't seem a likely
5144 attribute for a code section, and we are only looking at
5145 branches. However, implement it correctly here as a
5146 reference for other target relax_section functions. */
5148 {
5149 /* At this stage in linking, no SEC_MERGE symbol has been
5150 adjusted, so all references to such symbols need to be
5151 passed through _bfd_merged_section_offset. (Later, in
5152 relocate_section, all SEC_MERGE symbols *except* for
5153 section symbols have been adjusted.)
5155 gas may reduce relocations against symbols in SEC_MERGE
5156 sections to a relocation against the section symbol when
5157 the original addend was zero. When the reloc is against
5158 a section symbol we should include the addend in the
5159 offset passed to _bfd_merged_section_offset, since the
5160 location of interest is the original symbol. On the
5161 other hand, an access to "sym+addend" where "sym" is not
5162 a section symbol should not include the addend; Such an
5163 access is presumed to be an offset from "sym"; The
5164 location of interest is just "sym". */
5170 toff);
5174 }
5175 /* PLTREL24 addends are special. */
5184 /* If the branch is in range, no need to do anything. */
5188 /* Look for an existing fixup to this address. */
5194 {
5200 /* Oh dear, we can't reach a trampoline. Don't try to add
5201 one. We'll report an error later. */
5205 {
5209 }
5210 else
5211 {
5215 }
5224 /* Hijack the old relocation. Since we need two
5225 relocations for this use a "composite" reloc. */
5227 stub_rtype);
5230 /* Record the fixup so we don't do it again this section. */
5239 }
5240 else
5241 {
5246 /* Nop out the reloc, since we're finalizing things here. */
5248 }
5250 /* Get the section contents. */
5252 {
5253 /* Get cached copy if it exists. */
5256 else
5257 {
5258 /* Go get them off disk. */
5261 }
5262 }
5264 /* Fix up the existing branch to hit the trampoline. */
5267 {
5285 }
5286 }
5288 /* Write out the trampolines. */
5291 {
5294 bfd_vma val;
5297 do
5298 {
5302 }
5310 /* Branch around the trampolines. */
5318 {
5321 }
5322 else
5323 {
5326 }
5330 {
5332 i++;
5336 }
5338 }
5342 {
5345 else
5346 {
5347 /* Cache the symbols for elf_link_input_bfd. */
5349 }
5350 }
5354 {
5357 else
5358 {
5359 /* Cache the section contents for elf_link_input_bfd. */
5361 }
5362 }
5365 {
5368 else
5370 }
5375 error_return:
5385 }
5386 \f
5387 /* What to do when ld finds relocations against symbols defined in
5388 discarded sections. */
5390 static unsigned int
5392 {
5400 }
5401 \f
5402 /* Fill in the address for a pointer generated in a linker section. */
5404 static bfd_vma
5408 bfd_vma relocation,
5410 {
5416 {
5417 /* Handle global symbol. */
5423 }
5424 else
5425 {
5426 /* Handle local symbol. */
5431 }
5435 lsect);
5438 /* Offset will always be a multiple of four, so use the bottom bit
5439 as a "written" flag. */
5441 {
5446 }
5452 #ifdef DEBUG
5456 #endif
5458 /* Subtract out the addend, because it will get added back in by the normal
5459 processing. */
5461 }
5463 /* The RELOCATE_SECTION function is called by the ELF backend linker
5464 to handle the relocations for a section.
5466 The relocs are always passed as Rela structures; if the section
5467 actually uses Rel structures, the r_addend field will always be
5468 zero.
5470 This function is responsible for adjust the section contents as
5471 necessary, and (if using Rela relocs and generating a
5472 relocatable output file) adjusting the reloc addend as
5473 necessary.
5475 This function does not have to worry about setting the reloc
5476 address or the reloc symbol index.
5478 LOCAL_SYMS is a pointer to the swapped in local symbols.
5480 LOCAL_SECTIONS is an array giving the section in the input file
5481 corresponding to the st_shndx field of each local symbol.
5483 The global hash table entry for the global symbols can be found
5484 via elf_sym_hashes (input_bfd).
5486 When generating relocatable output, this function must handle
5487 STB_LOCAL/STT_SECTION symbols specially. The output symbol is
5488 going to be the section symbol corresponding to the output
5489 section, which means that the addend must be adjusted
5490 accordingly. */
5492 static bfd_boolean
5501 {
5507 Elf_Internal_Rela outrel;
5513 #ifdef DEBUG
5519 #endif
5524 {
5531 {
5537 {
5538 /* R_PPC_PLTREL24 is rather special. If non-zero, the
5539 addend specifies the GOT pointer offset within .got2. */
5541 }
5542 }
5544 }
5546 /* Initialize howto table if not already done. */
5557 {
5559 bfd_vma addend;
5560 bfd_reloc_status_type r;
5567 bfd_vma relocation;
5569 bfd_boolean unresolved_reloc;
5570 bfd_boolean warned;
5582 {
5588 }
5589 else
5590 {
5597 }
5599 /* TLS optimizations. Replace instruction sequences and relocs
5600 based on information we collected in tls_optimize. We edit
5601 RELOCS so that --emit-relocs will output something sensible
5602 for the final instruction stream. */
5606 {
5610 {
5614 }
5615 }
5617 /* Ensure reloc mapping code below stays sane. */
5628 {
5636 {
5637 bfd_vma insn;
5644 }
5650 {
5659 else
5662 /* add -> addi. */
5668 /* load and store indexed -> dform. */
5672 /* ldx, ldux, stdx, stdux -> ld, ldu, std, stdu. */
5677 /* lwax -> lwa. */
5679 else
5685 /* Was PPC_TLS which sits on insn boundary, now
5686 PPC_TPREL16_LO which is at insn+2. */
5688 }
5701 {
5702 tls_gdld_hi:
5706 else
5707 {
5711 }
5713 }
5726 {
5727 tls_get_addr_check:
5729 {
5734 bfd_vma offset;
5736 /* The next instruction should be a call to
5737 __tls_get_addr. Peek at the reloc to be sure. */
5755 /* OK, it checks out. Replace the call. */
5760 {
5761 /* IE */
5769 }
5770 else
5771 {
5772 /* LE */
5776 {
5777 /* Was an LD reloc. */
5781 }
5785 R_PPC_TPREL16_LO);
5787 }
5791 {
5792 /* We changed the symbol on an LD reloc. Start over
5793 in order to get h, sym, sec etc. right. */
5794 rel--;
5796 }
5797 }
5798 }
5800 }
5802 /* Handle other relocations that tweak non-addend part of insn. */
5805 {
5809 /* Branch taken prediction relocations. */
5813 /* Fall thru */
5815 /* Branch not taken prediction relocations. */
5826 /* Invert 'y' bit if not the default. */
5832 }
5840 {
5857 /* GOT16 relocations. Like an ADDR16 using the symbol's
5858 address in the GOT as relocation value instead of the
5859 symbol's value itself. Also, create a GOT entry for the
5860 symbol and put the symbol value there. */
5893 dogot:
5894 {
5895 /* Relocation is to the entry for this symbol in the global
5896 offset table. */
5897 bfd_vma off;
5910 {
5911 bfd_boolean dyn;
5916 /* This is actually a static link, or it is a
5917 -Bsymbolic link and the symbol is defined
5918 locally, or the symbol was forced to be local
5919 because of a version file. */
5920 ;
5921 else
5922 {
5925 }
5927 }
5928 else
5929 {
5933 }
5935 /* The offset must always be a multiple of 4. We use the
5936 least significant bit to record whether we have already
5937 processed this entry. */
5941 else
5942 {
5953 /* We might have multiple got entries for this sym.
5954 Initialize them all. */
5955 do
5956 {
5960 {
5963 }
5965 {
5968 }
5970 {
5973 }
5975 {
5978 }
5980 /* Generate relocs for the dynamic linker. */
5985 {
5991 {
5994 {
6001 outrel.r_info
6003 }
6004 }
6011 else
6014 {
6018 }
6023 }
6025 /* Init the .got section contents if we're not
6026 emitting a reloc. */
6027 else
6028 {
6034 {
6040 {
6044 }
6045 }
6048 }
6053 }
6058 }
6064 {
6066 {
6072 {
6076 {
6079 }
6080 }
6081 }
6082 }
6087 /* Addends on got relocations don't make much sense.
6088 x+off@got is actually x@got+off, and since the got is
6089 generated by a hash table traversal, the value in the
6090 got at entry m+n bears little relation to the entry m. */
6094 input_bfd,
6095 input_section,
6098 sym_name);
6099 }
6102 /* Relocations that need no special processing. */
6104 /* It makes no sense to point a local relocation
6105 at a symbol not in this object. */
6107 {
6110 input_bfd,
6111 input_section,
6113 TRUE))
6116 }
6126 /* Relocations that may need to be propagated if this is a shared
6127 object. */
6133 /* The TPREL16 relocs shouldn't really be used in shared
6134 libs as they will result in DT_TEXTREL being set, but
6135 support them anyway. */
6162 /* If these relocations are not to a named symbol, they can be
6163 handled right here, no need to bother the dynamic linker. */
6167 /* fall through */
6169 /* Relocations that always need to be propagated if this is a shared
6170 object. */
6182 /* r_symndx will be zero only for relocs against symbols
6183 from removed linkonce sections, or sections discarded by
6184 a linker script. */
6185 dodyn:
6188 /* Fall thru. */
6192 /* Fall thru. */
6200 || (ELIMINATE_COPY_RELOCS
6207 {
6210 #ifdef DEBUG
6215 #endif
6217 /* When generating a shared object, these relocations
6218 are copied into the output file to be resolved at run
6219 time. */
6221 {
6224 name = (bfd_elf_string_from_elf_section
6233 input_section),
6238 }
6254 {
6258 }
6259 else
6260 {
6265 else
6266 {
6272 {
6275 }
6276 else
6277 {
6280 /* We are turning this relocation into one
6281 against a section symbol. It would be
6282 proper to subtract the symbol's value,
6283 osec->vma, from the emitted reloc addend,
6284 but ld.so expects buggy relocs. */
6288 #ifdef DEBUG
6293 #endif
6294 }
6297 }
6298 }
6307 /* This reloc will be computed at runtime. We clear the memory
6308 so that it contains predictable value. */
6312 {
6316 }
6317 }
6322 {
6329 else
6334 }
6337 /* Fall thru */
6343 /* Fall thru */
6346 relax32:
6347 {
6354 /* We're clearing the bits for R_PPC_ADDR16_HA
6355 and R_PPC_ADDR16_LO here. */
6359 /* t0 is HA, t1 is LO */
6366 }
6369 /* Indirect .sdata relocation. */
6372 relocation
6377 /* Indirect .sdata2 relocation. */
6380 relocation
6385 /* Handle the TOC16 reloc. We want to use the offset within the .got
6386 section, not the actual VMA. This is appropriate when generating
6387 an embedded ELF object, for which the .got section acts like the
6388 AIX .toc section. */
6399 /* Relocation is to the entry for this symbol in the
6400 procedure linkage table. */
6401 {
6407 {
6408 /* We didn't make a PLT entry for this symbol. This
6409 happens when statically linking PIC code, or when
6410 using -Bsymbolic. */
6412 }
6419 else
6423 }
6426 /* Relocate against _SDA_BASE_. */
6428 {
6438 {
6442 input_bfd,
6443 sym_name,
6445 name);
6446 }
6451 }
6454 /* Relocate against _SDA2_BASE_. */
6456 {
6464 {
6468 input_bfd,
6469 sym_name,
6471 name);
6476 }
6481 }
6484 /* Relocate against either _SDA_BASE_, _SDA2_BASE_, or 0. */
6487 {
6498 {
6504 }
6508 {
6514 }
6518 {
6520 }
6522 else
6523 {
6527 input_bfd,
6528 sym_name,
6530 name);
6535 }
6542 }
6543 }
6546 /* Relocate against the beginning of the section. */
6555 /* Negative relocations. */
6581 input_bfd,
6583 sym_name);
6588 }
6590 /* Do any further special processing. */
6592 {
6609 /* It's just possible that this symbol is a weak symbol
6610 that's not actually defined anywhere. In that case,
6611 'sec' would be NULL, and we should leave the symbol
6612 alone (it will be set to zero elsewhere in the link). */
6614 /* Add 0x10000 if sign bit in 0:15 is set.
6615 Bits 0:15 are not used. */
6618 }
6620 #ifdef DEBUG
6625 sym_name,
6626 r_symndx,
6629 #endif
6634 {
6637 input_bfd,
6638 input_section,
6641 sym_name);
6643 }
6646 input_bfd,
6647 input_section,
6648 contents,
6650 relocation,
6651 addend);
6654 {
6656 {
6662 {
6663 /* Assume this is a call protected by other code that
6664 detect the symbol is undefined. If this is the case,
6665 we can safely ignore the overflow. If not, the
6666 program is hosed anyway, and a little warning isn't
6667 going to help. */
6670 }
6674 sym_name,
6677 input_bfd,
6678 input_section,
6681 }
6682 else
6683 {
6689 }
6690 }
6691 }
6693 #ifdef DEBUG
6695 #endif
6698 }
6699 \f
6700 #define PPC_LO(v) ((v) & 0xffff)
6701 #define PPC_HI(v) (((v) >> 16) & 0xffff)
6702 #define PPC_HA(v) PPC_HI ((v) + 0x8000)
6704 /* Finish up dynamic symbol handling. We set the contents of various
6705 dynamic sections here. */
6707 static bfd_boolean
6712 {
6715 bfd_boolean doneone;
6717 #ifdef DEBUG
6720 #endif
6728 {
6730 {
6731 Elf_Internal_Rela rela;
6733 bfd_vma reloc_index;
6737 else
6738 {
6744 }
6746 /* This symbol has an entry in the procedure linkage table.
6747 Set it up. */
6749 {
6750 bfd_vma got_offset;
6753 /* The first three entries in .got.plt are reserved. */
6756 /* Use the right PLT. */
6760 /* Fill in the .plt on VxWorks. */
6762 {
6772 }
6773 else
6774 {
6775 bfd_vma got_loc
6776 = (got_offset
6789 }
6796 /* This instruction is an immediate load. The value loaded is
6797 the byte offset of the R_PPC_JMP_SLOT relocation from the
6798 start of the .rela.plt section. The value is stored in the
6799 low-order 16 bits of the load instruction. */
6800 /* NOTE: It appears that this is now an index rather than a
6801 prescaled offset. */
6805 /* This instruction is a PC-relative branch whose target is
6806 the start of the PLT section. The address of this branch
6807 instruction is 20 bytes beyond the start of this PLT entry.
6808 The address is encoded in bits 6-29, inclusive. The value
6809 stored is right-shifted by two bits, permitting a 26-bit
6810 offset. */
6820 /* Fill in the GOT entry corresponding to this PLT slot with
6821 the address immediately after the the "bctr" instruction
6822 in this PLT entry. */
6829 {
6830 /* Fill in a couple of entries in .rela.plt.unloaded. */
6836 /* Provide the @ha relocation for the first instruction. */
6841 R_PPC_ADDR16_HA);
6846 /* Provide the @l relocation for the second instruction. */
6851 R_PPC_ADDR16_LO);
6856 /* Provide a relocation for the GOT entry corresponding to this
6857 PLT slot. Point it at the middle of the .plt entry. */
6862 R_PPC_ADDR32);
6865 }
6867 /* VxWorks uses non-standard semantics for R_PPC_JMP_SLOT.
6868 In particular, the offset for the relocation is not the
6869 address of the PLT entry for this function, as specified
6870 by the ABI. Instead, the offset is set to the address of
6871 the GOT slot for this function. See EABI 4.4.4.1. */
6876 }
6877 else
6878 {
6883 {
6884 /* We don't need to fill in the .plt. The ppc dynamic
6885 linker will fill it in. */
6886 }
6887 else
6888 {
6894 }
6895 }
6897 /* Fill in the entry in the .rela.plt section. */
6906 {
6907 /* Mark the symbol as undefined, rather than as defined in
6908 the .plt section. Leave the value alone. */
6910 /* If the symbol is weak, we do need to clear the value.
6911 Otherwise, the PLT entry would provide a definition for
6912 the symbol even if the symbol wasn't defined anywhere,
6913 and so the symbol would never be NULL. */
6916 }
6918 }
6921 {
6922 bfd_vma plt;
6931 {
6946 {
6955 }
6956 else
6957 {
6966 }
6967 }
6968 else
6969 {
6979 /* We only need one non-PIC glink stub. */
6981 }
6982 }
6983 else
6985 }
6988 {
6990 Elf_Internal_Rela rela;
6993 /* This symbols needs a copy reloc. Set it up. */
6995 #ifdef DEBUG
6997 #endif
7003 else
7014 }
7016 #ifdef DEBUG
7018 #endif
7020 /* Mark some specially defined symbols as absolute. */
7029 }
7030 \f
7031 static enum elf_reloc_type_class
7033 {
7035 {
7046 }
7047 }
7048 \f
7049 /* Finish up the dynamic sections. */
7051 static bfd_boolean
7054 {
7058 bfd_vma got;
7061 #ifdef DEBUG
7063 #endif
7070 else
7080 {
7088 {
7089 Elf_Internal_Dyn dyn;
7095 {
7099 else
7119 {
7123 }
7128 }
7131 }
7132 }
7134 /* Add a blrl instruction at _GLOBAL_OFFSET_TABLE_-4 so that a function can
7135 easily find the address of the _GLOBAL_OFFSET_TABLE_. */
7137 {
7139 bfd_vma val;
7151 }
7153 /* Fill in the first entry in the VxWorks procedure linkage table. */
7155 {
7156 /* Use the right PLT. */
7162 {
7163 bfd_vma got_value =
7173 }
7174 else
7175 {
7178 }
7187 {
7188 Elf_Internal_Rela rela;
7193 /* Output the @ha relocation for the first instruction. */
7202 /* Output the @l relocation for the second instruction. */
7211 /* Fix up the remaining relocations. They may have the wrong
7212 symbol index for _G_O_T_ or _P_L_T_ depending on the order
7213 in which symbols were output. */
7215 {
7216 Elf_Internal_Rela rel;
7232 }
7233 }
7234 }
7237 {
7240 bfd_vma res0;
7243 /*
7244 * PIC glink code is the following:
7245 *
7246 * # ith PLT code stub.
7247 * addis 11,30,(plt+(i-1)*4-got)@ha
7248 * lwz 11,(plt+(i-1)*4-got)@l(11)
7249 * mtctr 11
7250 * bctr
7251 *
7252 * # A table of branches, one for each plt entry.
7253 * # The idea is that the plt call stub loads ctr (and r11) with these
7254 * # addresses, so (r11 - res_0) gives the plt index * 4.
7255 * res_0: b PLTresolve
7256 * res_1: b PLTresolve
7257 * .
7258 * # Some number of entries towards the end can be nops
7259 * res_n_m3: nop
7260 * res_n_m2: nop
7261 * res_n_m1:
7262 *
7263 * PLTresolve:
7264 * addis 11,11,(1f-res_0)@ha
7265 * mflr 0
7266 * bcl 20,31,1f
7267 * 1: addi 11,11,(1b-res_0)@l
7268 * mflr 12
7269 * mtlr 0
7270 * sub 11,11,12 # r11 = index * 4
7271 * addis 12,12,(got+4-1b)@ha
7272 * lwz 0,(got+4-1b)@l(12) # got[1] address of dl_runtime_resolve
7273 * lwz 12,(got+8-1b)@l(12) # got[2] contains the map address
7274 * mtctr 0
7275 * add 0,11,11
7276 * add 11,0,11 # r11 = index * 12 = reloc offset.
7277 * bctr
7278 */
7280 {
7281 ADDIS_11_11,
7282 MFLR_0,
7283 BCL_20_31,
7284 ADDI_11_11,
7285 MFLR_12,
7286 MTLR_0,
7287 SUB_11_11_12,
7288 ADDIS_12_12,
7289 LWZ_0_12,
7290 LWZ_12_12,
7291 MTCTR_0,
7292 ADD_0_11_11,
7293 ADD_11_0_11,
7294 BCTR,
7295 NOP,
7296 NOP
7297 };
7300 {
7301 LIS_12,
7302 ADDIS_11_11,
7303 LWZ_0_12,
7304 ADDI_11_11,
7305 MTCTR_0,
7306 ADD_0_11_11,
7307 LWZ_12_12,
7308 ADD_11_0_11,
7309 BCTR,
7310 NOP,
7311 NOP,
7312 NOP,
7313 NOP,
7314 NOP,
7315 NOP,
7316 NOP
7317 };
7324 /* Build the branch table, one for each plt entry (less one),
7325 and perhaps some padding. */
7331 {
7334 }
7336 {
7339 }
7345 /* Last comes the PLTresolve stub. */
7347 {
7348 bfd_vma bcl;
7351 {
7354 }
7368 {
7373 }
7374 else
7375 {
7380 }
7381 }
7382 else
7383 {
7385 {
7388 }
7398 {
7403 }
7404 else
7405 {
7410 }
7411 }
7412 }
7415 }
7416 \f
7417 #define TARGET_LITTLE_SYM bfd_elf32_powerpcle_vec
7419 #define TARGET_BIG_SYM bfd_elf32_powerpc_vec
7421 #define ELF_ARCH bfd_arch_powerpc
7422 #define ELF_MACHINE_CODE EM_PPC
7423 #ifdef __QNXTARGET__
7424 #define ELF_MAXPAGESIZE 0x1000
7425 #else
7426 #define ELF_MAXPAGESIZE 0x10000
7427 #endif
7428 #define ELF_MINPAGESIZE 0x1000
7429 #define elf_info_to_howto ppc_elf_info_to_howto
7431 #ifdef EM_CYGNUS_POWERPC
7432 #define ELF_MACHINE_ALT1 EM_CYGNUS_POWERPC
7433 #endif
7435 #ifdef EM_PPC_OLD
7436 #define ELF_MACHINE_ALT2 EM_PPC_OLD
7437 #endif
7439 #define elf_backend_plt_not_loaded 1
7440 #define elf_backend_can_gc_sections 1
7441 #define elf_backend_can_refcount 1
7442 #define elf_backend_rela_normal 1
7444 #define bfd_elf32_mkobject ppc_elf_mkobject
7445 #define bfd_elf32_bfd_merge_private_bfd_data ppc_elf_merge_private_bfd_data
7446 #define bfd_elf32_bfd_relax_section ppc_elf_relax_section
7447 #define bfd_elf32_bfd_reloc_type_lookup ppc_elf_reloc_type_lookup
7448 #define bfd_elf32_bfd_set_private_flags ppc_elf_set_private_flags
7449 #define bfd_elf32_bfd_link_hash_table_create ppc_elf_link_hash_table_create
7451 #define elf_backend_object_p ppc_elf_object_p
7452 #define elf_backend_gc_mark_hook ppc_elf_gc_mark_hook
7453 #define elf_backend_gc_sweep_hook ppc_elf_gc_sweep_hook
7454 #define elf_backend_section_from_shdr ppc_elf_section_from_shdr
7455 #define elf_backend_relocate_section ppc_elf_relocate_section
7456 #define elf_backend_create_dynamic_sections ppc_elf_create_dynamic_sections
7457 #define elf_backend_check_relocs ppc_elf_check_relocs
7458 #define elf_backend_copy_indirect_symbol ppc_elf_copy_indirect_symbol
7459 #define elf_backend_adjust_dynamic_symbol ppc_elf_adjust_dynamic_symbol
7460 #define elf_backend_add_symbol_hook ppc_elf_add_symbol_hook
7461 #define elf_backend_size_dynamic_sections ppc_elf_size_dynamic_sections
7462 #define elf_backend_finish_dynamic_symbol ppc_elf_finish_dynamic_symbol
7463 #define elf_backend_finish_dynamic_sections ppc_elf_finish_dynamic_sections
7464 #define elf_backend_fake_sections ppc_elf_fake_sections
7465 #define elf_backend_additional_program_headers ppc_elf_additional_program_headers
7466 #define elf_backend_grok_prstatus ppc_elf_grok_prstatus
7467 #define elf_backend_grok_psinfo ppc_elf_grok_psinfo
7468 #define elf_backend_reloc_type_class ppc_elf_reloc_type_class
7469 #define elf_backend_begin_write_processing ppc_elf_begin_write_processing
7470 #define elf_backend_final_write_processing ppc_elf_final_write_processing
7471 #define elf_backend_write_section ppc_elf_write_section
7472 #define elf_backend_get_sec_type_attr ppc_elf_get_sec_type_attr
7473 #define elf_backend_plt_sym_val ppc_elf_plt_sym_val
7474 #define elf_backend_action_discarded ppc_elf_action_discarded
7478 /* VxWorks Target */
7480 #undef TARGET_LITTLE_SYM
7481 #undef TARGET_LITTLE_NAME
7483 #undef TARGET_BIG_SYM
7484 #define TARGET_BIG_SYM bfd_elf32_powerpc_vxworks_vec
7485 #undef TARGET_BIG_NAME
7488 /* VxWorks uses the elf default section flags for .plt. */
7491 {
7499 }
7501 /* Like ppc_elf_link_hash_table_create, but overrides
7502 appropriately for VxWorks. */
7505 {
7510 {
7518 }
7520 }
7522 /* Tweak magic VxWorks symbols as they are loaded. */
7523 static bfd_boolean
7531 {
7533 valp))
7537 }
7539 static void
7541 {
7544 }
7546 /* On VxWorks, we emit relocations against _PROCEDURE_LINKAGE_TABLE_, so
7547 define it. */
7548 #undef elf_backend_want_plt_sym
7549 #define elf_backend_want_plt_sym 1
7550 #undef elf_backend_want_got_plt
7551 #define elf_backend_want_got_plt 1
7552 #undef elf_backend_got_symbol_offset
7553 #define elf_backend_got_symbol_offset 0
7554 #undef elf_backend_plt_not_loaded
7555 #define elf_backend_plt_not_loaded 0
7556 #undef elf_backend_plt_readonly
7557 #define elf_backend_plt_readonly 1
7558 #undef elf_backend_got_header_size
7559 #define elf_backend_got_header_size 12
7561 #undef bfd_elf32_bfd_link_hash_table_create
7562 #define bfd_elf32_bfd_link_hash_table_create \
7563 ppc_elf_vxworks_link_hash_table_create
7564 #undef elf_backend_add_symbol_hook
7565 #define elf_backend_add_symbol_hook \
7566 ppc_elf_vxworks_add_symbol_hook
7567 #undef elf_backend_link_output_symbol_hook
7568 #define elf_backend_link_output_symbol_hook \
7569 elf_vxworks_link_output_symbol_hook
7570 #undef elf_backend_final_write_processing
7571 #define elf_backend_final_write_processing \
7572 ppc_elf_vxworks_final_write_processing
7573 #undef elf_backend_get_sec_type_attr
7574 #define elf_backend_get_sec_type_attr \
7575 ppc_elf_vxworks_get_sec_type_attr
7576 #undef elf_backend_emit_relocs
7577 #define elf_backend_emit_relocs \
7578 elf_vxworks_emit_relocs
7580 #undef elf32_bed
7581 #define elf32_bed ppc_elf_vxworks_bed