Commit Graph

774 Commits

Author SHA1 Message Date
Rafael Espindola
0d4b6d5c98 Avoid duplicated code.
This also fixes the linker script accounting for the ELF header in
some places but not in others.

llvm-svn: 282173
2016-09-22 16:47:21 +00:00
Rafael Espindola
9546fffbfe Handle empty sections with symbol assignments.
Before the symbols were becoming undefined.

llvm-svn: 282159
2016-09-22 14:40:50 +00:00
Rafael Espindola
24c073d1bb Once more unto the strict weak ordering, once more.
This should finally give a stable sorting over all implementations.

llvm-svn: 282118
2016-09-21 22:36:19 +00:00
Rafael Espindola
b6b8f6c308 Revert "Revert "Only restrict order if both sections are in the script.""
This reverts commit r282021, bringing back r282015.

The problem was that the comparison function was not a strict weak
ordering anymore, which this patch fixes.

Original message:

Only restrict order if both sections are in the script.

This matches gold and bfd behavior and is required to handle some scripts.

The script has to assume where PT_LOADs start in order to align that
spot. If we don't allow section it doesn't know about to move to the
middle, we can need more PT_LOADs and those will not be aligned.

llvm-svn: 282035
2016-09-20 22:43:15 +00:00
Davide Italiano
8f41f33f45 [Writer] Fix a typo. NFC.
llvm-svn: 281984
2016-09-20 16:57:02 +00:00
Rafael Espindola
b45fd70ef1 Disable --rosegment when we have linker scripts.
Linker scripts are responsible for aliging '.'. Since they are
designed for bfd which has no --rosegment, they don't align the RO to
RX transition.

llvm-svn: 281978
2016-09-20 15:22:27 +00:00
Davide Italiano
1c3c3953c6 [GC] Don't crash when printing the special Discarded GC section.
InputSection<ELFT>::Discarded has no name and it's not backed by
a file. Trying to report it as discared will cause a nullptr
dereference, therefore a crash. Skip it.

Differential Revision:   https://reviews.llvm.org/D24731

llvm-svn: 281946
2016-09-19 23:15:51 +00:00
Rafael Espindola
7d38273636 Map .data.rel.ro correctly.
An input section named .data.rel.ro now maps to an output section
named .data.rel.ro. Before we were mapping it to .data.

llvm-svn: 281931
2016-09-19 19:59:21 +00:00
Davide Italiano
6f862b1f07 [Writer] Rename variables to reflect reality. NFCI.
The InputSection variables in the Writer were named `C`. This
was because when the ELF linker was ported (from COFF)
the name `Chunks` for input sections was retained.
Luckily we switched to a more ELF-compliant jargon, but these
variables weren't reanamed accordingly during the transition.

llvm-svn: 281917
2016-09-19 17:38:39 +00:00
Rafael Espindola
aab6d5c52a Put SHF_ALLOC sections first, even with linker scripts.
This matches gold and bfd, and is pretty much required by some linker
scripts. They end with commands like

foo   0 : { *(bar) }

if we put any SHF_ALLOC sections after they can have an address that
is too low.

llvm-svn: 281778
2016-09-16 21:29:07 +00:00
Eugene Leviant
20d031948e Improve handling ASSERT outside SECTIONS block
Differential revision: https://reviews.llvm.org/D24450

llvm-svn: 281740
2016-09-16 15:30:47 +00:00
Rui Ueyama
2644cd1d88 Demangle symbols in "undefined symbol" error message.
llvm-svn: 281698
2016-09-16 03:52:45 +00:00
Rafael Espindola
1d98d6292f Make sure we create all necessary PT_LOADs.
We were some times stopping early when using linker scripts.

llvm-svn: 281647
2016-09-15 19:36:01 +00:00
George Rimar
d73ef1738b [ELF] - Implemented --section-start, -Ttext, -Tdata, -Tbss options.
--section-start=sectionname=org
Locate a section in the output file at the absolute address given by org. 
You may use this option as many times as necessary to locate multiple sections in the command line.
 org must be a single hexadecimal integer; for compatibility with other linkers, 
you may omit the leading `0x' usually associated with hexadecimal values. 
Note: there should be no white space between sectionname, the equals sign (“<=>”), and org.

-Tbss=org
-Tdata=org
-Ttext=org
Same as --section-start, with .bss, .data or .text as the sectionname.

Differential revision: https://reviews.llvm.org/D24294

llvm-svn: 281458
2016-09-14 13:07:13 +00:00
Rafael Espindola
d88d7166a8 Use murmurhash2 instead of fnv.
It is substantially faster by processing 8 bytes at a time.

llvm-svn: 281454
2016-09-14 11:32:57 +00:00
Eugene Leviant
e05336ffa1 [ELF] Replace HasContents with HasSections. NFC
llvm-svn: 281449
2016-09-14 08:32:36 +00:00
Rui Ueyama
38dbd3eea9 Simplify InputFile ownership management.
Previously, all input files were owned by the symbol table.
Files were created at various places, such as the Driver, the lazy
symbols, or the bitcode compiler, and the ownership of new files
was transferred to the symbol table using std::unique_ptr.
All input files were then free'd when the symbol table is freed
which is on program exit.

I think we don't have to transfer ownership just to free all
instance at once on exit.

In this patch, all instances are automatically collected to a
vector and freed on exit. In this way, we no longer have to
use std::unique_ptr.

Differential Revision: https://reviews.llvm.org/D24493

llvm-svn: 281425
2016-09-14 00:05:51 +00:00
Rui Ueyama
1e2e8eae5d [ELF] Set EF_ARM_EABI_VER5 for ARM
Without this flag set, an AArch64 Linux kernel won't try to load the executable
(even if a 32 bit arm kernel will run the binary just fine).

Patch by Martin Storsjö!

Differential revision: https://reviews.llvm.org/D24471

llvm-svn: 281394
2016-09-13 20:51:32 +00:00
Eugene Leviant
56b21c869e Linker script: implement AT [ (address) ] for PHDR
Differential revision: https://reviews.llvm.org/D24340

llvm-svn: 281024
2016-09-09 09:46:16 +00:00
Rafael Espindola
042a3f209b Compute section names only once.
This simplifies error handling as there is now only one place in the
code that needs to consider the possibility that the name is
corrupted. Before we would do it in every access.

llvm-svn: 280937
2016-09-08 14:06:08 +00:00
Eugene Leviant
3967ea05a9 Set entry address to 0x0 if no _start symbol
Differential revision: https://reviews.llvm.org/D23925

llvm-svn: 280912
2016-09-08 08:57:51 +00:00
Simon Atanasyan
d9ea656021 [ELF][MIPS] Do not create a hidden definition for __tls_get_addr on MIPS
On most architectures the linker is required to optimize away any
references to __tls_get_addr in case of static linking. As usual
a special case is MIPS - libc defines __tls_get_addr itself because
there are no TLS optimizations for this architecture.

llvm-svn: 280664
2016-09-05 15:42:29 +00:00
Petr Hosek
fdfcb796e1 [ELF] Do not omit debug sections when computing build-id
The primary use of build-id is in debugging, hence omitting debug
sections when computing it significantly reduces its usability as
changes in debug section content wouldn't alter the build-id.

Differential Revision: https://reviews.llvm.org/D24120

llvm-svn: 280421
2016-09-01 22:43:03 +00:00
Petr Hosek
e5d3ca5031 [ELF] Linkerscript: define symbols outside SECTIONS
Symbol assignments outside of SECTIONS command need to be created
even when SECTIONS command is not used.

Differential Revision: https://reviews.llvm.org/D23751

llvm-svn: 280252
2016-08-31 15:31:17 +00:00
Rafael Espindola
e7553e4eac Delete unnecessary template.
llvm-svn: 280237
2016-08-31 13:28:33 +00:00
George Rimar
9503f6d211 [ELF] - Introduce DiscardPolicy instead of 3 relative bool fields.
DiscardPolicy is enum replacing several boolean options. 
This approach is not only consistent with what we use for 
unresolveds (UnresolvedPolicy), but also should help to solve a problem 
of options with opposing meanings, mentioned in PR28843

Differential revision: https://reviews.llvm.org/D23868

llvm-svn: 280209
2016-08-31 08:46:30 +00:00
George Rimar
f21aade0d8 [ELF] - Introduce StripPolicy instead of Config->StripAll/StripDebug flags.
This approach is not only consistent with UnresolvedPolicy, 
but also should help to solve a problem 
of options with opposing meanings, mentioned in PR28843

Differential revision: https://reviews.llvm.org/D23869

llvm-svn: 280206
2016-08-31 08:38:11 +00:00
Eugene Leviant
e4f590faeb Allow .eh_frame_hdr to be placed before .eh_frame
Differential revision: https://reviews.llvm.org/D24041

llvm-svn: 280203
2016-08-31 07:43:50 +00:00
Eugene Leviant
933dae7435 Implement support for --build-id=uuid switch
Differential revision: https://reviews.llvm.org/D23349

llvm-svn: 279810
2016-08-26 09:55:37 +00:00
George Rimar
86ce267a4a [ELF] - Implemented --oformat binary option.
-oformat output-format
`-oformat' option can be used to specify the binary format for the output object file.

Patch implements binary format output type.

Differential revision: https://reviews.llvm.org/D23769

llvm-svn: 279726
2016-08-25 09:05:47 +00:00
Peter Smith
a52864a78c Canonicalize output section name for .ARM.exidx sections
The ARM Exception handling ABI requires that all ARM exception index
table sections have a prefix of .ARM.exidx and are combined into a
single contiguous block either in their own output section or as part
of another output section.
    
In general clang will output a single .ARM.exidx section per object,
but will use .ARM.exidx.<section name> when -ffunction-sections is used.
    
This change canonicalizes the names of sections with the .ARM.exidx
prefix to just .ARM.exidx, which ensures that there is only a single
output section.

Differential Revision: https://reviews.llvm.org/D23775

llvm-svn: 279617
2016-08-24 09:08:54 +00:00
Petr Hosek
4f7a5c3bb4 [ELF] Define __ehdr_start symbol
This symbol can be used by the program to examine its own headers.

Differential Revision: https://reviews.llvm.org/D23750

llvm-svn: 279452
2016-08-22 18:44:04 +00:00
Rui Ueyama
189b871a62 Format.
llvm-svn: 279415
2016-08-22 04:55:41 +00:00
George Rimar
e1937bb524 [ELF] - Give automatically generated __start_* and __stop_* symbols default visibility.
This patch is opposite to D19024, which made this symbols to be hidden by default.

Unfortunately FreeBSD loader wants to see
start_set_modmetadata_set/stop_set_modmetadata_set in the dynamic symbol table. 
They were not placed there because had hidden visibility.

Patch makes them to have default visibility again.

Differential revision: https://reviews.llvm.org/D23552

llvm-svn: 279262
2016-08-19 15:36:32 +00:00
Petr Hosek
1fb2ecc903 [ELF] Allow specifying the stack size
This option can be used to specify the stack size of the
PT_GNU_STACK segment.

Differential Revision: https://reviews.llvm.org/D23538

llvm-svn: 279013
2016-08-17 23:59:58 +00:00
George Rimar
8ceadb38a8 [ELF] - linkerscript AT keyword (in output section description) implemented.
The linker will normally set the LMA equal to the VMA. 
You can change that by using the AT keyword.
The expression lma that follows the AT keyword specifies 
the load address of the section.

Patch implements this keyword.

Differential revision: https://reviews.llvm.org/D19272

llvm-svn: 278911
2016-08-17 07:44:19 +00:00
Eugene Leviant
f9bc3bd2cf [ELF] Ignore .interp section in case linker script specifies PHDRS without PT_INTERP
llvm-svn: 278781
2016-08-16 06:40:58 +00:00
Eugene Leviant
a5c8a68535 [ELF] Do not add start and end symbols in case they are already defined
llvm-svn: 278657
2016-08-15 07:24:20 +00:00
Rui Ueyama
bdf836db1b Simplify output section ownership management.
One reason why we are (ab)using OutputSectionFactory class is
because it owns output sections. Technically there's no need
to have it own sections. So, this patch transfers the ownership
to Out<ELFT>.

llvm-svn: 278452
2016-08-12 01:10:17 +00:00
Eugene Leviant
ceabe80e97 [ELF] Symbol assignment within output section description
llvm-svn: 278322
2016-08-11 07:56:43 +00:00
Rui Ueyama
1034c9e342 Remove isOutputDynamic and use Out<ELFT>::DynSymTab instead.
This patch is to not instantiate DynSymTab and DynStrTab if the
output is not a dynamic output.

llvm-svn: 278095
2016-08-09 04:42:01 +00:00
Rui Ueyama
cbd434a6c4 Remove redundant variable.
llvm-svn: 278094
2016-08-09 04:31:21 +00:00
Rui Ueyama
a8f6feaa1a Separate {Preinit,Init,Fini}Arrays from Out<ELFT>::Dynamic.
Even if an output is not a dynamic object, the output may have
.{preinit,init,fini} sections. Therefore, managing these sections
as Out<ELFT>::Dynamic's members is not correct.

llvm-svn: 278093
2016-08-09 04:25:20 +00:00
Rui Ueyama
84907c5143 Do not pass the SymbolTable to writeResult.
The SymbolTable is always accessible as Symtab<ELFT>::X,
so no need to pass it as an argument.

llvm-svn: 278091
2016-08-09 03:38:23 +00:00
Rui Ueyama
210ef7fbd4 Remove redundant local variable.
llvm-svn: 278085
2016-08-09 01:35:39 +00:00
Rui Ueyama
30634d9b4f Reduce dependency to OutputSectionFactory.
The Factory class is too object-oriented-ish and easy to be abused.
This patch reduces dependency to that class. Eventually we want to
remove the dependency to that class from LinkerScript.

llvm-svn: 278084
2016-08-09 01:35:38 +00:00
Rui Ueyama
75118259ba Do not initialize Out<ELFT>::Opd until needed.
This change makes it clear that we need the variable only within
writeSections.

llvm-svn: 278083
2016-08-09 01:35:37 +00:00
Rui Ueyama
31f32fa62a Refactor getMipsEFlags.
Previously, we incrementally updated the reuslting flag as we check
file flags, so it was not very clear who is updating what flags.
This patch makes them pure functions -- that has no side effect and
don't update arguments to improve readability.

Now each function construct a patial result, and all resutls are then
bitwise-OR'ed to construct the final result.

This patch also creates a new file, Mips.cpp, to move all these
MIPS functions to a separate file.

Differential Revision: https://reviews.llvm.org/D23249

llvm-svn: 278042
2016-08-08 19:39:45 +00:00
George Rimar
28ac19c9ee [ELF] - Linkerscript: do not define _edata,_end,_etext if SECTIONS is used.
I faced that when tried to link FreeBSD kernel. 
It was "duplicate symbol: _edata in (internal) and (internal)" error.
_data was a shared symbol that came from hack.so. At first it was replaced with DefinedRegular by the code
disabled in this patch and later when script tried to define the same symbol - the error was shown.

In the same situation (as given in testcase) ld defines them as UND. gold defines as ABS with zero value. 
Patch just disables any operations of creating these symbols if script do layout.

Differential revision: https://reviews.llvm.org/D23206

llvm-svn: 277986
2016-08-08 08:42:48 +00:00
Simon Atanasyan
24c24fedba [ELF][MIPS] Produce a correct and complete set of MIPS ELF header flags
The patch extends the `getMipsEFlags` function. Now in that function
we iterate over all object files, parse ELF header flags and merge them.
If a file is incompatible with previously analyzed ones we show an error
or warning. That can happen if, for example, we try to link files with
incompatible ABI, ISA, NAN encoding etc.

There is an alternative solution. We can check and merge flags and
reject incompatible input modules in the `isCompatible` function which
is called from the `SymbolTable::addFile` method. But in that case we
have to save and keep somewhere a merged ELF flags combination to use it
later in the writer.

Differential Revision: http://reviews.llvm.org/D23161

llvm-svn: 277911
2016-08-06 05:11:41 +00:00