The .dynamic section of an ELF almost doesn't need to be written to with
the exception of the DT_DEBUG entry. For several reasons having a read
only .dynamic section would be useful. This change adds the -z keyword
"rodynamic" which forces .dynamic to be read-only. In this case DT_DEBUG
will not be emited.
Patch by Jake Ehrlich
Differential Revision: https://reviews.llvm.org/D33251
llvm-svn: 304024
I found this when builded llc binary using gcc 5.4.1 + LLD.
gcc produces duplicate entries in .debug_gnu_pubtypes section, ex:
UnifyFunctionExitNodes.cpp.o has:
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"
0x0000ac07 EXTERNAL TYPE "std::success_type<void*>"
clang produces single entry here:
0x0000d291 EXTERNAL TYPE "std::__success_type<void *>"
If we link output from gcc with LLD, that would produce excessive duplicate
entries in .gdb_index constant pool area. That does not seem affect gdb work,
but makes .gdb_index larger than it can be.
I also checked that gold filters out such duplicates too. Patch fixes it.
Differential revision: https://reviews.llvm.org/D32647
llvm-svn: 303975
https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html says:
"A CU vector in the constant pool is a sequence of offset_type values.
The first value is the number of CU indices in the vector.
Each subsequent value is the index and symbol attributes of a CU in the CU list."
Previously we keeped 2 values until the end, what was useless.
Initially was a part of D32647, though it is possible to split out.
Patch do that.
Differential revision: https://reviews.llvm.org/D33551
llvm-svn: 303973
It is not clear why a synthetic section wants to use padding defined
in the linker script. The padding is for the space between sections.
It was also missing a test.
llvm-svn: 303812
This reduces how many times we have to map from OutputSection to
OutputSectionCommand. It is a required step to moving
clearOutputSections earlier.
In order to always use writeTo in OutputSectionCommand we have to call
fabricateDefaultCommands for -r links and move section compression
after it.
llvm-svn: 303784
GetSection is a template because write calls relocate.
relocate has two parts. The non alloc code really has to be a
template, as it is looking a raw input file data.
The alloc part is only a template because of getSize.
This patch folds the value of getSize early, detemplates
getRelocTargetVA and splits relocate into a templated non alloc case
and a regular function for the alloc case. This has the nice advantage
of making sure we collect all the information we need for relocations
before getting to InputSection::relocateNonAlloc.
Since we know got is alloc, it can just call the function directly and
avoid the template.
llvm-svn: 303355
SymbolTableBaseSection was introduced.
Detemplation of SymbolTableSection should allow to detemplate more things.
Differential revision: https://reviews.llvm.org/D33124
llvm-svn: 303150
We should only ever expect this function to return a regular
InputSection; I would not expect a function definition to be in a
MergeInputSection or EhInputSection. We were previously crashing
in writeTo if this function returned a section that was not an
InputSection because we do not set OutSec for such sections.
This can happen in practice if a function is defined in an empty
section which shares its offset-in-file with a MergeInputSection,
as in the provided test case.
A better fix for this bug would be to fix the
DWARFUnit::collectAddressRanges() interface to provide section
information (see D33183), but this at least fixes the crash.
Differential Revision: https://reviews.llvm.org/D33176
llvm-svn: 303089
This reverts changes introduced in r302414 "[ELF] - Set DF_STATIC_TLS flag for i386 target."
Because DF_STATIC_TLS does not look to be used by glibc or anything else.
llvm-svn: 302884
This is PR32437.
DF_STATIC_TLS
If set in a shared object or executable, this flag instructs the
dynamic linker to reject attempts to load this file dynamically.
It indicates that the shared object or executable contains code
using a static thread-local storage scheme. Implementations need
not support any form of thread-local storage.
Patch checks if IE/LE relocations were used to check if code uses
static model. If so it sets the DF_STATIC_TLS flag.
Differential revision: https://reviews.llvm.org/D32354
llvm-svn: 302414
Strip on OpenBSD does not correctly handle an empty .eh_frame section
and produces broken binaries in that case. Currently lld creates such
an empty .eh_frame section, despite the fact that the OpenBSD crtend.o
explicitly inserts a terminator. The Linux LSB "standard":
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME
explicitly says that
The .eh_frame section shall contain 1 or more Call Frame Information (CFI) records.
This diff includes a test that specifically tests the issue I'm seeing
on OpenBSD.
Patch by Mark Kettenis!
llvm-svn: 301931
For an option -foo-bar-baz, we have Config->FooBarBaz. Since -rpath is
-rpath and not -r-path, it should be Config->Rpath instead Config->RPath.
llvm-svn: 301759
We can just use the existing SoName member variable. It now initially
contains what was in DefaultSoName and is modified if the .so has an
actual soname.
llvm-svn: 301259
We generally want to use uint64_t instead of uintX_t if the 64-bit
type works for both 32-bit and 64-bit because it is simpler than
the variable-size type.
llvm-svn: 300293
Executable sections should not be padded with zero by default. On some
architectures, 0x00 is the start of a valid instruction sequence, so can confuse
disassembly between InputSections (and indeed the start of the next InputSection
in some situations). Further, in the case of misjumps into padding, padding may
start to be executed silently.
On x86, the "0xcc" byte represents the int3 trap instruction. It is a single
byte long so can serve well as padding. This change switches x86 (and x86_64) to
use this value for padding in executable sections, if no linker script directive
overrides it. It also puts the behaviour into place making it easy to change the
behaviour of other targets when desired. I do not know the relevant instruction
sequences for trap instructions on other targets however, so somebody should add
this separately.
Because the old behaviour simply wrote padding in the whole section before
overwriting most of it, this change also modifies the padding algorithm to write
padding only where needed. This in turn has caused a small behaviour change with
regards to what values are written via Fill commands in linker scripts, bringing
it into line with ld.bfd. The fill value is now written starting from the end of
the previous block, which means that it always starts from the first byte of the
fill, whereas the old behaviour meant that the padding sometimes started mid-way
through the fill value. See the test changes for more details.
Reviewed by: ruiu
Differential Revision: https://reviews.llvm.org/D30886
Bugzilla: http://bugs.llvm.org/show_bug.cgi?id=32227
llvm-svn: 299635
This patch changes GnuHashTableSection implementation
to avoid depend on uintX_t and other ELFT stuff, reducing amount of
changes for following patch(es).
Differential revision: https://reviews.llvm.org/D31184
llvm-svn: 298998
.gnu.hash happen to contain only 32-bit integers for 32-bit arch,
but the section contents are not uniform array members, so setting
entsize doesn't make much sense. This behavior seems to have been
blindly copied from GNU linkers.
llvm-svn: 298934
This is a shorthand for Config->Wordsize == 8. So this is not strictly
necessary but seems handy. "Is 64 bit?" is easier to read than "Is
wordsize 8 byte?"
llvm-svn: 298463
Patch moves Sections array to
InputFile (root class for input files).
That allows to detemplate GdbIndexSection.
Differential revision: https://reviews.llvm.org/D30976
llvm-svn: 298345
This continues detemplation process.
Detemplating MipsGotSection<ELFT> is helpfull because can
help to detemplate getRelocTargetVA. (one more change is required)
It opens road to detemplation of GotSection<ELFT> and probably
something else after that.
Differential revision: https://reviews.llvm.org/D31090
llvm-svn: 298272
Does not introduce anything new,
just performs detemplate, using methods we
already have.
Differential revision: https://reviews.llvm.org/D30935
llvm-svn: 298269
We had a few Config member functions that returns configuration values.
For example, we had is64() which returns true if the target is 64-bit.
The return values of these functions are constant and never change.
This patch is to compute them only once to make it clear that they'll
never change.
llvm-svn: 298168
Do not take in account the `Live` flag while collecting .reginfo, .MIPS.options,
and .MIPS.abiflags input sections to produce corresponding output sections.
These sections have information purpose and should be always produced per
ABI requirements.
llvm-svn: 298093
With fix of next warning:
Writer.cpp:361:3: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
Original commit message:
Patch reuses BssSection section to simplify creation of
COMMON section.
Differential revision: https://reviews.llvm.org/D30690
llvm-svn: 298086
Was fixed, details on review page.
Original commit message:
That removes CopyRelSection class completely, making
Bss/BssRelRo to be just regular synthetics.
This is splitted from D30541 and polished.
Difference from D30541 that all logic of SharedSymbol
converting to DefinedRegular was removed for now and
probably will be posted as separate patch.
Differential revision: https://reviews.llvm.org/D30892
llvm-svn: 298062
That allows to detemplate getGotPltOffset/getGotPltVA
methods of SymbolBody and also will help to detemplate
DynamicReloc itself later.
llvm-svn: 297946
Patch splits In<ELFT> into 2 classes: one for non-templated sections,
second contains ELFT templated ones.
That allows to code that was detemplated to access non-templated sections freely,
and should open road for futher detemplation proccess.
Differential revision: https://reviews.llvm.org/D30939
llvm-svn: 297844
After introducing Config->is64Bit() and
recent changes in LinkerScriptBase, some
sections can be detemplated trivially. This
is one of such cases.
llvm-svn: 297825
StringTableSection was <ELFT> templated previously,
It disallow to de-template code that uses it,
for example LinkerScript<ELFT>::discard uses it as:
if (S == In<ELFT>::ShStrTab)
error("discarding .shstrtab section is not allowed");
It seems we can try to detemplate some of synthetic sections
and somehow make them available for non-templated calls.
(move out of In<ELFT> struct probably).
Differential revision: https://reviews.llvm.org/D30933
llvm-svn: 297815
That removes CopyRelSection class completely, making
Bss/BssRelRo to be just regular synthetics.
This is splitted from D30541 and polished.
Difference from D30541 that all logic of SharedSymbol
converting to DefinedRegular was removed for now and
probably will be posted as separate patch.
Differential revision: https://reviews.llvm.org/D30892
llvm-svn: 297814
Patch introduces Config->is64Bit() and with help of that detemplates
GotPltSection and IgotPltSection sections
Differential revision: https://reviews.llvm.org/D30944
llvm-svn: 297813
Using .eh_frame input section pattern in linker script currently
causes a crash; this is because .eh_frame input sections require
special handling since they're all combined into a synthetic
section rather than regular output section.
Differential Revision: https://reviews.llvm.org/D30627
llvm-svn: 297501
gold linker manual describes them as:
-z text Do not permit relocations in read-only segments
-z notext Permit relocations in read-only segments (default)
In LLD default is to not permit them. Patch implements -z notext.
Differential revision: https://reviews.llvm.org/D30530
llvm-svn: 297366
With this we have a single section hierarchy. It is a bit less code,
but the main advantage will be in a future patch being able to handle
foo = symbol_in_obj;
in a linker script. Currently that fails since we try to find the
output section of symbol_in_obj. With this we should be able to just
return an InputSection from the expression.
llvm-svn: 297313
This change moves the calls to finalizeContent() for each synthetic section
before createThunks(). This will allow us to assign addresses prior to
calling createThunks(). As addition of thunks may add to the static
symbol table and may affect the size of the mips got section we introduce a
couple of additional member functions to update these values.
Differential revision: https://reviews.llvm.org/D29983
llvm-svn: 297277
In compare with D30458, this makes Bss/BssRelRo to be pure
synthetic sections.
That removes CopyRelSection class completely, making
Bss/BssRelRo to be just regular synthetics.
SharedSymbols involved in creating copy relocations are
converted to DefinedRegular, what also simplifies things.
Differential revision: https://reviews.llvm.org/D30541
llvm-svn: 297008
That class had three member functions, and all of them are just reader
methods that did not depend on class members, so they can be just non-
member functions.
Probably we should reorganize the functions themselves because their
return types doesn't make much sense to me, but for now I just moved
these functions out of the class.
llvm-svn: 296700
Looks like .gdb.index and its support classes do things that they don't
have to or shouldn't do do. This patch addresses one of these issues.
GdbHashTab class is a hash table class. Just like other in-memory hash
tables, that incrementally updates its internal data and resizes buckets
as new elements are added so that key lookup is always fast.
But that is completely not necessary.
Unlike debuggers, we only produce hash tables for .gdb.index and
never read them. So incrementally updating a hash table in memory is
just a waste of resource and complicates the code. What we should
do is to accumulate symbols and then create the final hash table
at once.
llvm-svn: 296678
This implementation is probably slightly inefficient than before,
but that should be negligible because this is not a performance-
critical pass.
llvm-svn: 296570
I do not fully understand why we had these values in the tests, but
the new value matches what ld.bfd and ld.gold set, so I guess that
was just a mistake.
Differential Revision: https://reviews.llvm.org/D30441
llvm-svn: 296505
This reverts commit r296378.
I am pretty sure this is incorrect. In particular, for just
.cfi_startproc
nop
.cfi_endproc
We now add an extra 4 zeros that neither bfd nor gold add.
llvm-svn: 296503
In other places in LLD, we use write32<E> instead of Elf_Word.
This patch uses the same technique in the hash table classes.
The hash table classes needs improving as they have almost no
comments. We at least need to describe the hash table structure
and why we have to support two different on-disk hash tables
for the same purpose. I'll do that later.
llvm-svn: 296439
Previously, these two functions put their symbols in different queues.
Now that the queues have been merged. So there's no point to keep two
separate functions.
llvm-svn: 296435
That function doesn't use any member of SymbolTableSection, so I
couldn't see a reason to make it a member of that class. The function
takes a SymbolBody, so it is more natural to make it a member of
SymbolBody.
llvm-svn: 296433
Previously, there were three conditions: .symtab, .dynsym or we are
producing a relocatable output. Turned out that the third condition is
the same as the first one. This patch removes that third condition and
simplify code.
llvm-svn: 296431
The previous code was a bit hard to understand because it unnecessarily
distinguished local and non-local symbols. It had NumLocals member
variable, but that variable didn't have a number of local symbols but
had some value that I cannot describe easily.
This patch rewrites SynbolTableSection::finalizeContents and
SymbolTableSection::writeTo to make it easy to understand. NumLocals
member variable has been removed, and writeGlobalSymbols and
writeLocalSymbols have been merged into one function.
There's still a piece of code that I think unnecessary. I'm not removing
that code in this patch, but will do in a follow-up patch.
llvm-svn: 296423
This part of code is hard to understand because NumLocals does not
actually mean the number of local symbols but something else (!).
We need to rewrite. But before that we need to clean it up.
llvm-svn: 296400
Patch by Mark Kettenis.
Currenlty ld.lld does not add a terminator (a CIE with its length field
set to zero) to the .eh_frame sections it generates. While the relevant
standards (the AMD64 SysV ABI and the Linux LSB) are not explicit about
this, such a terminator is expected by some unwinder implementations and
seems to be always emitted by ld.bfd. In addition to that, the Linux LSB
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME
explicitly says that
The .eh_frame section shall contain 1 or more Call Frame Information
(CFI) records.
Currently, if the .eh_frame sections of the input files only contain
terminators, ld.lld emits a zero=sized .eh_frame section
which clearly doesn't meet that requirement.
The diff makes sure a terminator gets added to each .eh_frame section
and adjusts all the relevant tests to account for that. An additional
test isn't needed as these adjustments mean that the existence of the
terminator is tested for by several tests already.
Differential Revision: https://reviews.llvm.org/D30335
llvm-svn: 296378
The list of all input sections was defined in SymbolTable class for a
historical reason. The list itself is not a template. However, because
SymbolTable class is a template, we needed to pass around ELFT to access
the list. This patch moves the list out of the class so that it doesn't
need ELFT.
llvm-svn: 296309
With this we complete the transition out of special output sections,
and with the previous patches it should be possible to merge
OutputSectionBase and OuputSection.
llvm-svn: 296023
With the current design an InputSection is basically anything that
goes directly in a OutputSection. That includes plain input section
but also synthetic sections, so this should probably not be a
template.
llvm-svn: 295993
This change moves the SymbolBodies with isLocal() == true before the global
symbols then calculating NumLocals rather than assuming all locals are
added before globals and the first NumLocals have isLocal() == true. This
permits Thunks to be moved after the pass that adds global symbols from
synthetics to the symbol table.
Differential revision: https://reviews.llvm.org/D30085
llvm-svn: 295650
This patch removes NeedsCopyOrPltAddr and instead add two variables,
NeedsCopy and NeedsPltAddr. This uses one more bit in Symbol class,
but the actual size doesn't increase because we had unused bits.
This should improve code readability.
llvm-svn: 295287
In the target dependent code we already always return a int64_t. In
the target independent code we carefully use uintX_t, which has the
same result given 2 complement rules.
This just simplifies the code to use int64_t everywhere.
llvm-svn: 295263
Unfortunately some consumers of our .o files produced with -r expect
only one section symbol per section. That is true of at least of go's
own linker.
Combining them is a somewhat convoluted process. We have to create a
symbol for every section since we don't know which ones will be
needed. The relocation sections also have to be written first to
handle the Elf_Rel addend.
I did consider a completely different approach:
We could remove the -r special case of relocation sections when
reading. We would instead have a copyRelocs function that is used
instead of scanRelocs. It would create a DynamicReloc for each
relocation and a RelocationSection for each input relocation section.
A complication of such change is that DynamicReloc would have to take
a section index and a input section instead of a symbol since with
-emit-relocs some DynamicReloc would hold relocations referring to the
dynamic symbol table and other to the static symbol table.
That would be a pretty big change, and if we do it it is probably
better to do it as a refactoring.
llvm-svn: 294816
Much of the code in PltSection and IPltSection is similar, we identify
the IPlt by a HeaderSize of 0 and alter our behaviour in the member
functions appropriately:
-Iplt does not have a header
-Iplt always follows after the Plt
Differential Revision: https://reviews.llvm.org/D29664
llvm-svn: 294579
When we need a copy relocation we create a synthetic SHT_NOBITS
section that contains the right amount of ZI and assign it to either
.bss or .rel.ro.bss as appropriate. This allows the dynamic relocation
to be placed on the InputSection, removing the last case where a
dynamic relocation is stored as an offset from the OutputSection. This
has the side effect that we can run assignOffsets() after scanRelocs()
without losing the additional ZI needed for the copy relocations.
Differential Revision: https://reviews.llvm.org/D29637
llvm-svn: 294577
With a synthetic merge section we can have, for example, a single
.rodata section with stings, fixed sized constants and non merge
constants.
I can be simplified further by not setting Entsize, but that is
probably better done is a followup patch.
This should allow some cleanup in the linker script code now that
every output section command maps to just one output section.
llvm-svn: 294005
Thunks are now implemented by redirecting the relocation to the
symbol S, to a symbol TS in a Thunk. The Thunk will transfer control
to S. This has the following implications:
- All the side-effects of Thunks happen within createThunks()
- Thunks are no longer stored in InputSections and Symbols no longer
need to hold a pointer to a Thunk
- The synthetic Thunk sections need to be merged into OutputSections
This implementation is almost a direct conversion of the existing
Thunks with the following exceptions:
- Mips LA25 Thunks are placed before the InputSection that defines
the symbol that needs a Thunk.
- All ARM Thunks are placed at the end of the OutputSection of the
first caller to the Thunk.
Range extension Thunks are not supported yet so it is optimistically
assumed that all Thunks can be reused.
This is a recommit of r293283 with a fixed comparison predicate as
std::merge requires a strict weak ordering.
Differential revision: https://reviews.llvm.org/D29327
llvm-svn: 293757
Thunks are now implemented by redirecting the relocation to the
symbol S, to a symbol TS in a Thunk. The Thunk will transfer control
to S. This has the following implications:
- All the side-effects of Thunks happen within createThunks()
- Thunks are no longer stored in InputSections and Symbols no longer
need to hold a pointer to a Thunk
- The synthetic Thunk sections need to be merged into OutputSections
This implementation is almost a direct conversion of the existing
Thunks with the following exceptions:
- Mips LA25 Thunks are placed before the InputSection that defines
the symbol that needs a Thunk.
- All ARM Thunks are placed at the end of the OutputSection of the
first caller to the Thunk.
Range extension Thunks are not supported yet so it is optimistically
assumed that all Thunks can be reused.
Differential Revision: https://reviews.llvm.org/D29129
llvm-svn: 293283
Mapping symbols allow a mapping symbol aware disassembler to
correctly disassemble the PLT when the code immediately prior to the
PLT is Thumb.
To implement this we add a function to add symbols with local
binding to be defined in SyntheticSymbols.
Differential Revision: https://reviews.llvm.org/D28956
llvm-svn: 293044
Next code crashed under MSVS2015 for me:
this->OutSec->Info = this->Info = 1 + It - Symbols.begin();
Because It was end() and addition of 1 is not allowed.
vector implementation catched and failed that inside:
_Myiter& operator+=(difference_type _Off)
{ // increment by integer
#if _ITERATOR_DEBUG_LEVEL == 2
if (this->_Getcont() == 0
|| this->_Ptr + _Off < ((_Myvec *)this->_Getcont())->_Myfirst
|| ((_Myvec *)this->_Getcont())->_Mylast < this->_Ptr + _Off)
{ // report error
_DEBUG_ERROR("vector iterator + offset out of range");
_SCL_SECURE_OUT_OF_RANGE;
llvm-svn: 292940
The sh_info field of the SHT_SYMTAB section holds the index for the
first non-local symbol. When there are global symbols that are output
with STB_LOCAL binding due to having hidden visibility or matching
the local version from a version script, the calculated value of
NumLocals + 1 does not account for them. This change accounts for
global symbols being output with local binding.
Differential Revision: https://reviews.llvm.org/D28950
llvm-svn: 292910
Currently ld.lld -r allocates space for common symbols, whereas ld.bfd
-r doesn't. As a result the OpenBSD makefile bits for creating libraries
fail as they use ld -X -r to strip local symbols, which results in
duplicate symbol errors because space for the common symbols has been
allocated.
The diff also implements the --define-commons option such that allocation
of commons can be forced even if -r is used.
Patch by Mark Kettenis.
llvm-svn: 292878
Previously we stored kept locals in a KeptLocalSyms arrays,
belonged to files.
Patch makes SymbolTableSection to store locals in Symbols member,
that already present and was used for globals.
SymbolTableSection already had NumLocals counter member, so change
itself is trivial.
That allows to simplify handling of -r,
Body::DynsymIndex is no more used as "symbol table index" for relocatable
output.
Change was suggested during review of D28773 and opens road for D28612.
Differential revision: https://reviews.llvm.org/D29021
llvm-svn: 292789
On MIPS .got section cannot be included into the PT_GNU_RELRO segment.
Sometimes it might work, but in general it is unsupported. One of the
problem is that all sections marked by SHF_MIPS_GPREL should be grouped
together because data in these sections is addressable with a gp
relative address, but such sections might be writable.
This patch exclude mips .got from PT_GNU_RELRO segment and group
SHF_MIPS_GPREL sections.
llvm-svn: 292161
The freebsd dynamic linker doesn't check if the value is null (and it
is reasonable for it to do that). That means that producing a .so with
a null DT_INIT/DT_FINI causes the base address to be called.
This should fix the libreoffice build.
llvm-svn: 291944
When reserving copy relocation space for a shared symbol, scan the DSO's
program headers to see if the symbol is in a read-only segment. If so,
reserve space for that symbol in a new synthetic section named .bss.rel.ro
which will be covered by the relro program header.
This fixes the security issue disclosed on the binutils mailing list at:
https://sourceware.org/ml/libc-alpha/2016-12/msg00914.html
Differential Revision: https://reviews.llvm.org/D28272
llvm-svn: 291524
DefinedSynthetic is not created for a real ELF object, so it doesn't
have to be a template function. It has a virtual st_value, which is
either 32 bit or 64 bit, but we can simply use 64 bit.
llvm-svn: 290241
Older versions of BFD generate libraries with .MIPS.abiflags that only
concatenate the individual .MIPS.abiflags sections instead of merging.
Patch by Alexander Richardson.
Differential revision: https://reviews.llvm.org/D27770
llvm-svn: 290237
I thought for a while about how to remove it, but it looks like we
can just copy the file for now. Of course I'm not happy about that,
but it's just less than 50 lines of code, and we already have
duplicate code in Error.h and some other places. I want to solve
them all at once later.
Differential Revision: https://reviews.llvm.org/D27819
llvm-svn: 290062
Patch continues work started in D24706 and D25821.
in this patch symbol table and constant pool areas were
added to .gdb_index section output.
This one finishes the implementation of --gdb-index functionality in LLD.
Differential revision: https://reviews.llvm.org/D26283
llvm-svn: 289810
Patch continues work started in D24706,
in this patch address area was added to .gdb_index section output.
Differential revision: https://reviews.llvm.org/D25821
llvm-svn: 289790
The VA of _gp was being truncated to 32 bits when calling getVa(), but
for 64bit MIPS we need to write a 64 bit value to .MIPS.options.
Patch by Alexander Richardson.
Differential revision: https://reviews.llvm.org/D27672
llvm-svn: 289432
The i386 glibc ld.so expects the .got.slot entry that is relocated by a
R_386_IRELATIVE relocation to point directly at the ifunc resolver and
not the address of the PLT entry + 6 (thus entering the lazy resolver).
This is also the case for ARM and I suspect it is because these use REL
relocations and can't use the addend field to store the address of the
ifunc resolver. If the lazy resolver is used we get an error message
stating that only R_386_JUMP_SLOT is supported.
As ARM and i386 share the same code, I've removed the ARM specific test
and added a writeIgotPlt() function that by default calls writeGotPlt().
ARM and i386 override this to write the address of the ifunc resolver.
Differential Revision: https://reviews.llvm.org/D27581
llvm-svn: 289198
This change introduces new synthetic sections IpltSection, IgotPltSection
that represent the ifunc entries that would previously have been put in
the PltSection and the GotPltSection. The separation makes sure that
the R_*_IRELATIVE relocations are placed after the non R_*_IRELATIVE
relocations, which permits ifunc resolvers to know that the .got.plt
slots will be initialized prior to the resolver being called.
A secondary benefit is that for ARM we can move the IgotPltSection and its
dynamic relocations to the .got and .rel.dyn as the ARM glibc expects all
the R_*_IRELATIVE relocations to be in the .rel.dyn
Differential revision: https://reviews.llvm.org/D27406
llvm-svn: 289045
This change continues what was started by D27040
Now all allocatable synthetics should be available from script side.
Differential revision: https://reviews.llvm.org/D27131
llvm-svn: 288150
The MipsGotSection::getPageEntryOffset calculates index of GOT entry
with a "page" address. Previously this method changes the state
of MipsGotSection because it modifies PageIndexMap field. That leads
to the unpredictable results if getPageEntryOffset called from multiple threads.
The patch makes getPageEntryOffset constant. To do so it calculates GOT
entry index but does not update PageIndexMap field. Later in the
MipsGotSection::writeTo method linker calculates "page" addresses and
writes them to the output.
llvm-svn: 288129
If output section which referenced by R_MIPS_GOT_PAGE or R_MIPS_GOT16
relocations is small (less that 0x10000 bytes) and occupies two adjacent
0xffff-bytes pages, current formula gives incorrect number of required "page"
GOT entries. The problem is that in time of calculation we do not know
the section address and so we cannot calculate number of 0xffff-bytes
pages exactly.
This patch fix the formula. Now it gives a correct number of pages in
the worst case when "small" section intersects 0xffff-bytes page
boundary. From the other side, sometimes it adds one more redundant GOT
entry for each output section. But usually number of output sections
referenced by GOT relocations is small.
llvm-svn: 288127
Right now we just remember a SymbolBody for each got entry and
duplicate a bit of logic to decide what value, if any, should be
written for that SymbolBody.
With ARM there will be more complicated values, and it seems better to
just use the relocation code to fill the got entries. This makes it
clear that each entry is filled by the dynamic linker or by the static
linker.
llvm-svn: 288107
This is important for cases like:
.sdata : {
*(.got.plt .got)
...
}
That was not supported before as there was no way to get access to
synthetic sections from script.
More details on review page.
Differential revision: https://reviews.llvm.org/D27040
llvm-svn: 287913
The .ARM.exidx table has an entry for each function with the first entry
giving the start address of the function, the table is sorted in ascending
order of function address. Given a PC value, the unwinder will search the
table for the entry that contains the PC value.
If the table entry happens to be the last, the range of the addresses that
the final unwinding table describes will extend to the end of the address
space. To prevent an incorrect address outside the address range of the
program matching the last entry we follow ld.bfd's example and add a
sentinel EXIDX_CANTUNWIND entry at the end of the table. This gives the
final real table entry an upper bound.
In addition the llvm libunwind unwinder currently depends on the presence
of a sentinel entry (PR31091).
Differential revision: https://reviews.llvm.org/D26977
llvm-svn: 287869
Offset between beginning of a .got section and _gp symbols used in MIPS
GOT relocations calculations. Usually the expression looks like
VA + Offset - GP, where VA is the .got section address, Offset - offset
of the GOT entry, GP - offset between .got and _gp. Also there two "magic"
symbols _gp_disp and __gnu_local_gp which hold the offset mentioned above.
These symbols might be referenced by MIPS relocations.
Now the linker always defines _gp symbol and uses hardcoded value for
its initialization. So offset between .got and _gp is 0x7ff0. The _gp_disp
and __gnu_local_gp defined if required and initialized by 0x7ff0.
In fact that is not correct because _gp symbol might be defined by a linker
script and holds arbitrary value. In that case we need to use this value
in relocation calculation and initialize _gp_disp and __gnu_local_gp
properly.
The patch fixes the problem and completes fixing the bug #30311.
https://llvm.org/bugs/show_bug.cgi?id=30311
Differential revision: https://reviews.llvm.org/D27036
llvm-svn: 287832
We have different functions to stringize objects to construct
error messages. For InputFile, we have getFilename, and for
InputSection, we have getName. You had to memorize them.
I think this is the case where the function overloading comes in handy.
This patch defines toString() functions that are overloaded for all these
types, so that you just call it in error().
Differential Revision: https://reviews.llvm.org/D27030
llvm-svn: 287787
Some synthetic sections are not derived calsses of SyntehticSection.
They are derived directly from InputSection. For consistencly, we should
use SyntheticSection.
llvm-svn: 287606
MIPS GOT handling is very different from other targets so it is better
to keep the code in the separatre section class MipsGotSection. This
patch introduces the new section and moves all MIPS specific code from
GotSection to the new class. I did not rename fields and methods in the
MipsGotSection class to reduce the diff and plan to do that by the
separate commit.
Differential revision: https://reviews.llvm.org/D26733
llvm-svn: 287150
This patch introduces the following changes:
- DynamicSection now inherits InputSection<ELFT> and was moved
to SyntheticSections.h/.cpp.
- Link and Entsize fields of DynamicSection are propagated to
its output section
- In<ELFT>::SyntheticSections was removed.
- Finalization of synthetic sections was removed from
OutputSection<ELFT>::finalize. Now finalizeSyntheticSections is
used instead.
Differential revision: https://reviews.llvm.org/D26603
llvm-svn: 286950
Summary:
This patch adds a ".comment" section to an output. The comment
section contains the linker's version string. You can now
find out whether a binary is created by LLD or not using objdump
command like this.
$ objdump -s -j .comment foo
foo: file format elf64-x86-64
Contents of section .comment:
0000 00474343 3a202855 62756e74 7520342e .GCC: (Ubuntu 4.
0010 382e342d 32756275 6e747531 7e31342e 8.4-2ubuntu1~14.
...
00c0 766d2f74 72756e6b 20323835 38343629 vm/trunk 285846)
00d0 004c696e 6b65723a 204c4c44 20342e30 .Linker: LLD 4.0
00e0 2e302028 7472756e 6b203238 36343036 .0 (trunk 286406
00f0 2900 ).
Compilers emits .comment section as well, so the output contains
both compiler and linker information.
Alternative considered:
I first tried to add a SHT_NOTE section because GNU gold does that.
A NOTE section starts with a header which contains content type.
It turned out that ld.gold sets type NT_GNU_GOLD_VERSION to their
NOTE section. So the NOTE type is only for GNU gold (surprise!)
Next, I tried to create ".linker-version" section. However, it seems
that reusing the existing ".comment" section is better because 1)
other tools already know about .comment section and is able to strip
it and 2) the result contans not only linker info but also compiler
info.
Differential Revision: https://reviews.llvm.org/D26487
llvm-svn: 286496
Previously, we have both input and output section for .MIPS.abiflags.
Now we have only one class for .MIPS.abiflags, which is MipsAbiFlagsSection.
This class is a synthetic input section.
.MIPS.abiflags sections are handled as regular sections until
the control reaches Writer. Writer then aggregates all sections
whose type is SHT_MIPS_ABIFLAGS to create a single synthesized
input section. The synthesized section is then processed normally
as if it came from an input file.
llvm-svn: 286398
Previously, we have both input and output sections for .reginfo and
.MIPS.options. Now for each such sections we have one synthetic input
sections: MipsReginfoSection and MipsOptionsSection respectively.
Both sections are handled as regular sections until the control reaches
Writer. Writer then aggregates all sections whose type is SHT_MIPS_REGINFO
or SHT_MIPS_OPTIONS to create a single synthesized input section. In that
moment Writer also save GP0 value to the MipsGp0 field of the corresponding
ObjectFile. This value required for R_MIPS_GPREL16 and R_MIPS_GPREL32
relocations calculation.
Differential revision: https://reviews.llvm.org/D26444
llvm-svn: 286397
This is similar to what was done for InputSection.
With this the various fields are stored in host order and only
converted to target order when writing.
llvm-svn: 286327
Patch switches computing of --build-id hash to tree.
This is the way when input data is splitted by chunks,
hash is computed for each one in threaded/non-threaded way.
At the end hash is conputed for result tree.
With or without -threads the result hash is the same.
Differential revision: https://reviews.llvm.org/D26199
llvm-svn: 286061
A CommonInputSection is a section containing all common symbols.
That was an input section but was abstracted in a different way
than the synthetic input sections because it was written before
the synthetic input section was invented.
This patch rewrites CommonInputSection as a synthetic input section
so that it behaves better with other sections.
llvm-svn: 286053
This change fixes a bug that was introduced by r285851.
r285851 converted .interp section as an output section to an input
section. But I forgot to make it a "Live" section, so if -gc-section
is given, it was garbage collected.
llvm-svn: 286025
We are going to have many more classes for linker-synthesized
input sections, so it's worth to be added to a separate file
than to the file for regular input sections.
llvm-svn: 285740
Petr Hosek