Commit Graph

56 Commits

Author SHA1 Message Date
Nick Kledzik f373c77f50 [mach-o] Fix lazy binding offsets
The way lazy binding works in mach-o is that the linker generates a helper
function and has the stub (PLT) initially jump to it.  The helper function
pushes an extra parameter then jumps into dyld.  The extra parameter is an
offset into the lazy binding info where dyld will find the information about
which symbol to bind and way lazy binding pointer to update.

llvm-svn: 221654
2014-11-11 01:31:18 +00:00
Nick Kledzik 37d1aa715a [mach-o] remove extra leading underscore on __bss and __got
llvm-svn: 221425
2014-11-06 01:14:12 +00:00
Nick Kledzik 5c4693d8d2 [mach-o] Add support for interposing tuples section
Darwin uses two-level-namespace lookup for symbols which means the static
linker records where each symbol must be found at runtime.  Thus defining a
symbol in a dylib loaded earlier will not effect where symbols needed by
later dylibs will be found.  Instead overriding is done through a section
of type S_INTERPOSING which contains tuples of <interposer, interposee>.

llvm-svn: 221421
2014-11-06 01:09:13 +00:00
Tim Northover f98b1c9960 [mach-o] remove __compact_unwind atoms once __unwind_info has been generated
The job of the CompactUnwind pass is to turn __compact_unwind data (and
__eh_frame) into the compressed final form in __unwind_info. After it's done,
the original atoms are no longer relevant and should be deleted (they cause
problems during actual execution, quite apart from the fact that they're not
needed).

llvm-svn: 221301
2014-11-04 21:57:32 +00:00
Nick Kledzik 761d6549bc [mach-o] Support data-only dylibs
In final linked shared images, the __TEXT segment contains both code and
the mach-o header/load-commands.  In the case of a data-only dylib, there is
no code, so we need to force the addition of the __TEXT segment.

llvm-svn: 220597
2014-10-24 22:19:22 +00:00
Shankar Easwaran 2b67fca033 Sort include files according to convention.
llvm-svn: 220131
2014-10-18 05:33:55 +00:00
Nick Kledzik 5172067391 [mach-o] Add support for upward linking
To deal with cycles in shared library dependencies, the darwin linker supports
marking specific link dependencies as "upward".  An upward link is when a
lower level library links against a higher level library.

llvm-svn: 219949
2014-10-16 19:31:28 +00:00
Tim Northover 1cc4fb76da [mach-o] make __unwind_info defer to __eh_frame when necessary.
Not all situations are representable in the compressed __unwind_info format,
and when this happens the entry needs to point to the more general __eh_frame
description.

Just x86_64 implementation for now.

rdar://problem/18208653

llvm-svn: 219836
2014-10-15 19:32:21 +00:00
Tim Northover cf78d37fd6 [mach-o] create __unwind_info section on x86_64
This is a minimally useful pass to construct the __unwind_info section in a
final object from the various __compact_unwind inputs. Currently it doesn't
produce any compressed pages, only works for x86_64 and will fail if any
function ends up without __compact_unwind.

rdar://problem/18208653

llvm-svn: 218703
2014-09-30 21:29:54 +00:00
Yaron Keren 9682c8553e Modified per David Blakie suggestion.
llvm-svn: 218198
2014-09-21 05:07:44 +00:00
Yaron Keren 84f3816f85 Silence these C4715 warnings from Visual C++ (NFC)
llvm\tools\lld\lib\readerwriter\macho\macholinkingcontext.cpp(647):
warning C4715: 'lld::MachOLinkingContext::exportSymbolNamed' :
not all control paths return a value

llvm\tools\lld\lib\readerwriter\macho\machonormalizedfilefromatoms.cpp(723):
warning C4715: '`anonymous namespace'::Util::getSymbolTableRegion' :
not all control paths return a value

While all enum values do appear in the switch, an uninitialized or corrupted
enum variable would not be caught without the default: case in the switch.

llvm-svn: 218197
2014-09-21 04:13:45 +00:00
Nick Kledzik 1050b57a0b [mach-o] Fix two-level namespace ordinals
On darwin, the linker tools records which dylib (DSO) each undefined was found
in, and then at runtime, the loader (dyld) only looks in that one specific
dylib for each undefined symbol.  Now that llvm-objdump can display that info
I can write test cases.

llvm-svn: 217898
2014-09-16 20:27:28 +00:00
Tim Northover af3075b93f [mach-o]: implement -image_base option on Darwin.
As suggested by Nick, this will make __unwind_info implementation more natural,
and it'd have to be done at some point anyway.

llvm-svn: 217486
2014-09-10 10:39:57 +00:00
Nick Kledzik 1bebb2832e [mach-o] Add support for arm64 (AAarch64)
Most of the changes are in the new file ArchHandler_arm64.cpp.  But a few
things had to be fixed to support 16KB pages (instead of 4KB) which iOS arm64
requires.  In addition the StubInfo struct had to be expanded because
arm64 uses two instruction (ADRP/LDR) to load a global which requires two
relocations.  The other mach-o arches just needed one relocation.

llvm-svn: 217469
2014-09-09 23:52:59 +00:00
Nick Kledzik b7035ae367 [mach-o] Add support for -pie and -no_pie
There is a bit (MH_PIE) in the flags field of the mach_header which tells
the kernel is a program was built position independent (for ASLR).  The linker
automatically attempts to build programs PIE if they are built for a recent
OS version.  But the -pie and -no_pie options override that default behavior.

llvm-svn: 217408
2014-09-09 00:17:52 +00:00
Nick Kledzik 141330aef6 [mach-o] Add support for using export tries
On Darwin at runtime, dyld will prefer to use the export trie of a dylib instead
of the traditional symbol table (which is large and requires a binary search).

This change enables the linker to generate an export trie and to prefer it if
found in a dylib being linked against.  This also simples the yaml for dylibs
because the yaml form of the trie can be reduced to just a sequence of names.

llvm-svn: 217066
2014-09-03 19:52:50 +00:00
Nick Kledzik 7820c80f7d [mach-o] support N_NO_DEAD_STRIP nlist.desc bit
Mach-O symbols can have an attribute on them means their content should never be
dead code stripped.  This translates to deadStrip() == deadStripNever.

llvm-svn: 216234
2014-08-21 22:18:30 +00:00
Nick Kledzik 8c0bf75ef5 [mach-o] Add support for -exported_symbols_list and -keep_private_externs
Both options control the final scope of atoms.

When -exported_symbols_list <file> is used, the file is parsed into one
symbol per line in the file.  Only those symbols will be exported (global)
in the final linked image.

The -keep_private_externs option is only used with -r mode. Normally, -r
mode reduces private extern (scopeLinkageUnit) symbols to non-external. But
add the -keep_private_externs option keeps them private external.

llvm-svn: 216146
2014-08-21 01:59:11 +00:00
Nick Kledzik b47683223f [mach-o] set ordinal in n_desc for undefined symbols
Mach-o uses "two-level namespace" where each undefined symbols is associated
with a specific dylib. This means at runtime the loader (dyld) does need to
search all loaded dylibs for that symbol but rather just the one specified.

Now that llvm-nm -m prints out that info, properly set that info, and test
it in the hello world test cases.

llvm-svn: 215598
2014-08-13 23:11:42 +00:00
Nick Kledzik 2fcbe822c0 [mach-o] Add support for -sectalign option
The -sectalign option is used to increase the alignment required for a section.
It required some reworking of how the __TEXT segment is laid out because that
segment also contains the mach_header and load commands. And the size of load
commands depend on the number of segments, sections, and dependent dylibs used.

Using this option will simplify some future test cases because the final
address of code can be pinned down, making tests of its content easier.

llvm-svn: 214268
2014-07-30 00:58:06 +00:00
Nick Kledzik 54fd4e5fcb [mach-o] Implement interworking between thumb and arm code
All iOS arm processor support switching between arm and thumb mode at call sites
by using the BLX instruction (instead of BL).  But the compiler does not know
the implementation mode for extern functions, so the linker must update BL/BLX
instructions to match what is linked is actually linked together.  In addition,
pointers to functions (such as vtables) must have the low bit set if the target
of the pointer is a thumb mode function.

llvm-svn: 214140
2014-07-28 23:06:09 +00:00
Nick Kledzik 21921375cc [mach-o] Add support for LC_DATA_IN_CODE
Sometimes compilers emit data into code sections (e.g. constant pools or
jump tables). These runs of data can throw off disassemblers.  The solution
in mach-o is that ranges of data-in-code are encoded into a table pointed to
by the LC_DATA_IN_CODE load command.

The way the data-in-code information is encoded into lld's Atom model is that
that start and end of each data run is marked with a Reference whose offset
is the start/end of the data run.  For arm, the switch back to code also marks
whether it is thumb or arm code.

llvm-svn: 213901
2014-07-24 23:06:56 +00:00
Nick Kledzik 7e9808f7de [mach-o] add initial support for modes in arm code.
This patch just supports marking ranges that are thumb code (vs arm code).
Future patches will mark data and jump table ranges. The ranges are encoded
as References with offsetInAtom being the start of the range and the target
being the same atom.

llvm-svn: 213712
2014-07-23 00:51:37 +00:00
Nick Kledzik e1aaced0cb [mach-o] Add test case for armv6 (arm not thumb) hello world
llvm-svn: 213592
2014-07-22 00:49:49 +00:00
Nick Kledzik 2d432353ba [mach-o] implement more x86 and x86_64 relocation support
Add support for adding section relocations in -r mode.  Enhance the test
cases which validate the parsing of .o files to also round trip.  They now
write out the .o file and then parse that, verifying all relocations survived
the round trip.

llvm-svn: 213333
2014-07-17 23:16:21 +00:00
Nick Kledzik 2458bec7e7 [mach-o] refactor KindHandler into ArchHandler and simplify passes.
All architecture specific handling is now done in the appropriate
ArchHandler subclass.

The StubsPass and GOTPass have been simplified.  All architecture specific
variations in stubs are now encoded in a table which is vended by the
current ArchHandler.

llvm-svn: 213187
2014-07-16 19:49:02 +00:00
Nick Kledzik b6e8ce8250 [mach-o] add x86 test case to build hello world. Fix bugs it uncovered.
llvm-svn: 212247
2014-07-03 02:01:21 +00:00
Tim Northover 301c4e690a [mach-o] add representation for LC_ID_DYLIB to MachONormalizedFile
It still needs to be tied into BinaryReader, but this allows reasonably
sensible creation of SharedLibrary atoms on MachO.

llvm-svn: 212093
2014-07-01 08:15:41 +00:00
Tim Northover b5bf686b58 MachO: stop iterating past the end of an array
When trying to map atom types to sections, we were iterating through an array
until we hit a sentinel value. There's no need for such dances when range-based
for loops are available.

llvm-svn: 212035
2014-06-30 10:30:00 +00:00
Tim Northover 9ee9935358 MachO: re-enable writing of compact-unwind sections.
This isn't really the right place to put them in final object files (that would
be __TEXT,__unwind_info), but the format is different between relocatable and
final objects, which means we really need a pass to handle the translation.

For now, re-emitting in __LD,__compact_unwind is harmless (dyld ignores it and
moves straight on to inspecting __TEXT,__eh_frame), and sidesteps an assertion
failure when processing files containing compact-unwind info.

llvm-svn: 212032
2014-06-30 09:49:37 +00:00
Tim Northover 7b0a1306b4 MachO: align segment virtual addresses to page size.
Segments must occupy a multiple of the page size in memory (4096 currently). We
check for this when emitting files, but the placement algorithm broke down for
the second non-__TEXT segment encountered: the offset wasn't aligned up to 4096
before starting its layout.

llvm-svn: 212031
2014-06-30 09:49:33 +00:00
Nick Kledzik 3f69076278 [mach-o] refactor x86_64 relocation handling.
This is first step in reworking how mach-o relocations are processed.
The existing KindHandler is going to become a delgate/helper object for
processing architecture specific references.  The KindHandler knows how
to convert mach-o relocations into References and back, as well, as fixing
up the content the relocation is on.

One of the messy things about mach-o relocations is that they sometime 
come in pairs, but the pairs still convert to one lld::Reference. So, the
conversion has to detect pairs (arch specific) and change the stride.

llvm-svn: 211921
2014-06-27 18:25:01 +00:00
Tim Northover d30a1f2cb2 MachO: rename _outputFileType to avoid shadowing parent field.
llvm-svn: 211367
2014-06-20 15:59:00 +00:00
Rafael Espindola 54427ccef3 include system_error directly.
llvm-svn: 210801
2014-06-12 17:15:58 +00:00
Rafael Espindola 1675d51eac Run llvm/utils/sort_includes.py in a few files.
This will reduce the noise in a followup patch.

llvm-svn: 210800
2014-06-12 17:12:28 +00:00
Nick Kledzik 936d5205bb [mach-o] fix use of resolver functions to not cause duplicate sections.
The previous commit uncovered a bug in the mach-o writer whereby two __text
sections were created.  But the test case did not catch that.  So I updated
the test case to run the linker a second time, reading the output of the
first pass.  

llvm-svn: 210624
2014-06-11 01:30:55 +00:00
Nick Kledzik 6085539bed [mach-o] add support for parsing resolver functions
llvm-svn: 210612
2014-06-11 00:24:16 +00:00
Nick Kledzik ec140834d4 [mach-o] refactor mach-o output section selection to be table driven.
In -r mode the sections use the table used to parse .o files.  Otherwise
use final exectuable table.  No functionality change.

llvm-svn: 210506
2014-06-10 01:50:00 +00:00
Nick Kledzik acfad80250 [mach-o] Add support for custom sections
llvm-svn: 209928
2014-05-30 22:51:04 +00:00
Nick Kledzik f317d66c31 [mach-0] Add support for parsing compact unwind info section
llvm-svn: 209865
2014-05-29 23:50:48 +00:00
Nick Kledzik b367c25f28 [mach-o] Add support for parsing __eh_frame section. Generalize support for whether symbols in a section are ignored or illegal
llvm-svn: 209858
2014-05-29 23:07:20 +00:00
Nick Kledzik 9ede702bc4 [mach-o] Add support for parsing CFString sections
llvm-svn: 209844
2014-05-29 20:44:21 +00:00
Nick Kledzik a4a08d31cf [mach-o] Add support for initializers and terminators in object files
llvm-svn: 209700
2014-05-27 23:20:52 +00:00
Nick Kledzik 3e90e5f187 [mach-o] Add support for reading utf16 string literal sections
llvm-svn: 209684
2014-05-27 20:25:06 +00:00
Nick Kledzik a0c13a2420 [mach-o] parse literal sections into atoms
llvm-svn: 209379
2014-05-22 01:42:06 +00:00
Nick Kledzik 61fdef6086 [mach-o] Add support and test cases for parsing tentative definitions
llvm-svn: 208919
2014-05-15 20:59:23 +00:00
Rui Ueyama b461b1c785 s/llvm::dyn_cast/dyn_cast/
llvm-svn: 205404
2014-04-02 06:54:46 +00:00
Shankar Easwaran 3d8de47f76 Fix trailing whitespace.
llvm-svn: 200182
2014-01-27 03:09:26 +00:00
Nick Kledzik 6edd722a2c [mach-o] enable mach-o and native yaml to be intermixed
The main goal of this patch is to allow "mach-o encoded as yaml" and "native
encoded as yaml" documents to be intermixed.  They are distinguished via 
yaml tags at the start of the document.  This will enable all mach-o test cases
to be written using yaml instead of checking in object files.

The Registry was extend to allow yaml tag handlers to be registered.  The
mach-o Reader adds a yaml tag handler for the tag "!mach-o". 

Additionally, this patch fixes some buffer ownership issues.  When parsing
mach-o binaries, the mach-o atoms can have pointers back into the memory 
mapped .o file.  But with yaml encoded mach-o, name and content are ephemeral, 
so a copyRefs parameter was added to cause the mach-o atoms to make their
own copy.  

llvm-svn: 198986
2014-01-11 01:07:43 +00:00
Joey Gouly ceb16dedef [MachO] Begin to add some MachO specific File/Atoms, and add the start of
normalizedToAtoms.

llvm-svn: 198459
2014-01-03 23:12:02 +00:00