Patch by Matthew Koontz!
Before, direct calls to __wrap_sym would not map to valid PLT entries,
so they would crash at runtime. This change maps such calls to the same
PLT entry as calls to sym that are then wrapped.
Differential Revision: https://reviews.llvm.org/D48502
llvm-svn: 336609
Patch by Rahul Chaudhry!
This change adds experimental support for SHT_RELR sections, proposed
here: https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
Pass '--pack-dyn-relocs=relr' to enable generation of SHT_RELR section
and DT_RELR, DT_RELRSZ, and DT_RELRENT dynamic tags.
Definitions for the new ELF section type and dynamic array tags, as well
as the encoding used in the new section are all under discussion and are
subject to change. Use with caution!
Pass '--use-android-relr-tags' with '--pack-dyn-relocs=relr' to use
SHT_ANDROID_RELR section type instead of SHT_RELR, as well as
DT_ANDROID_RELR* dynamic tags instead of DT_RELR*. The generated
section contents are identical.
'--pack-dyn-relocs=android+relr --use-android-relr-tags' enables both
'--pack-dyn-relocs=android' and '--pack-dyn-relocs=relr': lld will
encode the relative relocations in a SHT_ANDROID_RELR section, and pack
the rest of the dynamic relocations in a SHT_ANDROID_REL(A) section.
Differential Revision: https://reviews.llvm.org/D48247
llvm-svn: 336594
This patch adds the target call back relaxTlsLdToLe to support TLS relaxation
from local dynamic to local exec model.
Differential Revision: https://reviews.llvm.org/D48293
llvm-svn: 336559
The reference implementation uses a case-insensitive string
comparison for strings of equal length. This will cause the
string "tEo" to compare less than "VUo". However we were using
a case sensitive comparison, which would generate the opposite
outcome. Switch to a case insensitive comparison. Also, when
one of the strings contains non-ascii characters, fallback to
a straight memcmp.
The only way to really test this is with a DIA test. Before this
patch, the test will fail (but succeed if link.exe is used instead
of lld-link). After the patch, it succeeds even with lld-link.
llvm-svn: 336464
They were failing in Chromium's packaging builds with:
C:\b\rr\tmphqfaff\w\src\third_party\llvm\tools\lld\test\COFF\pdb-globals-dia-vfunc-collision2.test:24:8:
error: expected string not found in input
CHECK: func [0x00001060+ 0 - 0x0000106c-12 | sizeof= 12] (FPO) virtual int __cdecl A132()
^
<stdin>:8:11: note: scanning from here
struct S [sizeof = 8] {
^
<stdin>:9:2: note: possible intended match here
func [0x00001060+ 0 - 0x0000106c-12 | sizeof= 12] (FPO) virtual int __cdecl S::A132()
^
Maybe due to different DIA versions.
llvm-svn: 336424
Remove support for linking microMIPS 64-bit code because this kind of
ISA is rarely used and unsupported by LLVM.
Differential revision: https://reviews.llvm.org/D48949
llvm-svn: 336413
We add an option to dump the entire global / public symbol record
stream. Previously we would dump globals or publics, but not both.
And when we did dump them, we would always dump them in the order
they were referenced by the corresponding hash streams, not in
the order they were serialized in. This patch adds a lower level
mode that just dumps the whole stream in serialization order.
Additionally, when dumping global-extras, we now dump the hash
bitmap as well as the record offset instead of dumping all zeros
for the offsets.
llvm-svn: 336407
It seems like the debugger first computes a symbol's bucket,
and then does a binary search of entries in the bucket using the
symbol's name in order to find it. If the bucket entries are not
in sorted order, this obviously won't work. After this patch a
couple of simple test cases show that we generate an exactly
identical GSI hash stream, which is very nice.
llvm-svn: 336405
In this file we only have to handle the v2 ABI, so what we need to do
is to just make sure that all object files have v2 or unspecified version
number.
Differential Revision: https://reviews.llvm.org/D48112
llvm-svn: 336372
We call switchTo() from assignAddresses() for switching to Aether,
and from assignOffsets().
First calls assignOffsets() one by one for each output section.
(https://github.com/llvm-mirror/lld/blob/master/ELF/LinkerScript.cpp#L1045)
That I believe means the condition removed in this patch is dead.
llvm-svn: 336356
Currently, there are only OutputSection and SymbolAssignment
commands possible at the first level under SECTIONS tag.
Hence, dyn_cast was excessive.
llvm-svn: 336354
Test case ensures lld generates an error if unable to
write an empty index file for lazy object file that is not added to link.
This covers the following line with a test:
https://github.com/llvm-mirror/lld/blob/master/ELF/LTO.cpp#L206
llvm-svn: 336340
I think code is dead, because the only way to see
Path as empty seems would be if replaceThinLTOSuffix()
replaced some prefix with empty prefix (making the result
Path empty).
But it is impossible to pass the empty prefix,
we would file in driver:
https://github.com/llvm-mirror/lld/blob/master/ELF/Driver.cpp#L669
llvm-svn: 336338
This is https://bugs.llvm.org//show_bug.cgi?id=37836
Previously LLD could assign to Dot or set the address
for the section with address expression but did not advance
the position in a memory region.
Patch fixes the issue.
llvm-svn: 336335
Currently, there are only OutputSection and SymbolAssignment
commands possible at the first level under SECTIONS tag.
So, shouldSkip() contained dead "return true".
Patch simplifies the code.
llvm-svn: 336282
We did not have a test that would test that
_etext address is equal to etext, _end == end and _edata == edata.
Because of that, the following line was never
executed when running our tests:
https://github.com/llvm-mirror/lld/blob/master/ELF/Writer.cpp#L928
Patch fixes that.
llvm-svn: 336280
We have a following comment for createEmptyIndex caller code:
// If LazyObjFile has not been added to link, emit empty index files.
// This is needed because this is what GNU gold plugin does and we have a
// distributed build system that depends on that behavior.
Though createEmptyIndex() itself
(https://github.com/llvm-mirror/lld/blob/master/ELF/LTO.cpp#L202)
is never called in our test cases.
Patch adds a test.
llvm-svn: 336270
ELF spec doesn't allow a relocation to point to a deduplicated
COMDAT section. Unfortunately this happens in practice (e.g. .eh_frame)
We have a code in MarkLive.cpp for that and it was uncovered by any test case:
https://github.com/llvm-mirror/lld/blob/master/ELF/MarkLive.cpp#L199
Patch adds a test.
llvm-svn: 336259
LLD removes empty output sections otherwise specified in the linker
script. Prior to this change however, if section descriptions included
ANY kind of symbol assignment, then the consequent output section would
not be removed, even if the assignment was marked with PROVIDE and not
actually triggered (i.e. the symbol was never referenced). This change
modifies the isDiscarable function to ignore such directives when
determining whether a section should be discarded, in keeping with
bfd's behaviour. Symbol assignments that do result in a symbol
definition will continue to result in a kept section (this is not
actually the same as bfd's behaviour, but it is simpler, and probably
makes more sense).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D48771
llvm-svn: 336184
The AArch64 -fix-cortex-a53-843419 is missing a test case for the load and
store exclusive instructions. This was leading to a function not being
covered in the codebase. This change adds two new instruction sequences to
be recognised as an instance of the erratum, one with a load exclusive the
other with a store exclusive.
Differential Revision: https://reviews.llvm.org/D48840
llvm-svn: 336181
Comment in the test case says that:
## This inputs previously created a 4gb temporarily file under 32 bit
## configuration. Issue was fixed. There is no clean way to check that from here.
## This testcase added for documentation purposes.
The intention of the test was to create such huge file
in case if our code will be broken again.
And currently it documents we do not create huge outputs.
r336129 changed -o to /dev/null and broke the intentions of the test case.
llvm-svn: 336179
We have the following code that is uncovered with the test:
https://github.com/llvm-mirror/lld/blob/master/ELF/Target.cpp#L95
This patch:
1) Removes "!IS" check. Because at that point of execution
(we are reolving the relocations during writing output)
we should only have InputSection type of the sections in the vector.
(because we already converted MergeInputSection in mergeSections()
and combined EhInputSections in combineEhFrameSections()).
2) Covers the "!IS->getParent()" with the test.
llvm-svn: 336106
CIEs augmentation string can have 'P' character,
what means the next byte is the personality encoding, a DW_EH_PE_xxx value.
This is followed by a pointer to the personality function.
We had the support of the different encodings earlier, but had no test cases.
This change adds coverage of DW_EH_PE_absptr/DW_EH_PE_signed/DW_EH_PE_udata2/DW_EH_PE_sdata2 and
DW_EH_PE_udata8/DW_EH_PE_sdata8 cases for place below:
https://github.com/llvm-mirror/lld/blob/master/ELF/EhFrame.cpp#L123
llvm-svn: 335969
I do not think this code was ever alive,
because the following code says we can have OutputSection and
SymbolAssignment cases only. We already handle both of them.
https://github.com/llvm-mirror/lld/blob/master/ELF/ScriptParser.cpp#L502
FWIW, it is dead in the LLD code coverage reports I am running either.
llvm-svn: 335958
In this mode, we retain the symbol table, but skip the actual debug
information.
Differential Revision: https://reviews.llvm.org/D48745
llvm-svn: 335947
With this set, we retain the symbol table, but skip the actual debug
information.
This is meant to be used by the MinGW frontend.
Differential Revision: https://reviews.llvm.org/D48745
llvm-svn: 335946
This change effects the behavior of --export-all. Previously
--export-all would only effect symbols that survived GC. Now
--export-all will prevent any non-local symbols from being GCed.
Differential Revision: https://reviews.llvm.org/D48673
llvm-svn: 335878
Function symbols that come from bitcode have not signatures.
After LTO when the real symbols are read in we need to make
sure that we set the signature on the existing symbol.
the signature-less undefined functions.
Differential Revision: https://reviews.llvm.org/D48693
llvm-svn: 335875
Summary:
Control flow guard works best when targets it checks are 16-byte aligned.
Microsoft's link.exe helps ensure this by aligning code from sections
that are referenced from the gfids table to 16 bytes when linking with
-guard:cf, even if the original section specifies a smaller alignment.
This change implements that behavior in lld-link.
See https://crbug.com/857012 for more details.
Reviewers: ruiu, hans, thakis, zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48690
llvm-svn: 335864
This test case adds test for the line that was uncovered previously:
https://github.com/llvm-mirror/lld/blob/master/ELF/EhFrame.cpp#L175
it errors out, but we now can test that we have expected flow,
which is different for CIE of version 1 and CIE of version 3.
llvm-svn: 335840
We has precompiled object with unsupported FDE version (=2).
It is possible to use llvm-mc instead for this test.
Patch do this change.
llvm-svn: 335818
Currently, ICF does not enable threading if we have less than 1024
sections in each equivalence class.
And the following code is uncovered by our test cases:
https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp#L404
This patch adds a test case that triggers the mentioned code to execute.
llvm-svn: 335738
The local dynamic TLS access on PPC64 ELF v2 ABI uses R_PPC64_GOT_DTPREL16*
relocations when a TLS variables falls outside 2 GB of the thread storage
block. This patch adds support for these relocations by adding a new RelExpr
called R_TLSLD_GOT_OFF which emits a got entry for the TLS variable relative
to the dynamic thread pointer using the relocation R_PPC64_DTPREL64. It then
evaluates the R_PPC64_GOT_DTPREL16* relocations as the got offset for the
R_PPC64_DTPREL64 got entries.
Differential Revision: https://reviews.llvm.org/D48484
llvm-svn: 335732
This patch adds the target call back relaxTlsGdToLe to support TLS relaxation
from global dynamic to local exec model.
The relaxation performs the following transformation:
addis r3, r2, x@got@tlsgd@ha --> nop
addi r3, r3, x@got@tlsgd@l --> addis r3, r13, x@tprel@ha
bl __tls_get_addr(x@tlsgd) --> nop
nop --> addi r3, r3, x@tprel@l
Differential Revision: https://reviews.llvm.org/D48082
llvm-svn: 335730
This is PR36768.
Linker script OVERLAYs are described in 4.6.9. Overlay Description of the spec:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/sections.html
They are used to allow output sections which have different LMAs but the same VAs
and used for embedded programming.
Currently, LLD restricts overlapping of sections and that seems to be the most desired
behaviour for defaults. My thoughts about possible approaches for PR36768 are on the bug page,
this patch implements OVERLAY keyword and allows VAs overlapping for sections that within the overlay.
Differential revision: https://reviews.llvm.org/D44780
llvm-svn: 335714
This generalizes the old heuristic placing SHT_DYNSYM SHT_DYNSTR first in the readonly SHF_ALLOC segment.
Reviewers: espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D48406
llvm-svn: 335674
Patch adds support for relaxing the general-dynamic tls sequence to
initial-exec.
the relaxation performs the following transformation:
addis r3, r2, x@got@tlsgd@ha --> addis r3, r2, x@got@tprel@ha
addi r3, r3, x@got@tlsgd@l --> ld r3, x@got@tprel@l(r3)
bl __tls_get_addr(x@tlsgd) --> nop
nop --> add r3, r3, r13
and instead of emitting a DTPMOD64/DTPREL64 pair for x, we emit a single
R_PPC64_TPREL64.
Differential Revision: https://reviews.llvm.org/D48090
llvm-svn: 335651
Summary:
Currently when --no-rosegment is specified or a linker script with SECTIONS command is used,
.rodata (A) .text (AX) are assigned the same rank and .rodata may be placed after .text .
This increases the gap between .text and .bss and can cause pc-relative relocation overflow (e.g. gcc crtbegin.o crtbegin.S have R_X86_64_PC32 relocation from .text to .bss).
This patch makes SingleRoRx affect only segment layout, not section layout. As a consequence, .rodata will be placed before .text regardless of SingleRoRx.
Reviewers: espindola, ruiu, grimar, echristo, javed.absar
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D48405
llvm-svn: 335627
rLLD329787 added the stable sorting to SymbolTableBaseSection::postThunkContents.
I profiled the Mozilla (response-O0.txt) from lld-speed-test package and found
std::stable_sort is showing up in profile results and consuming the 3.1% of the total
CPU time in the RelWithDebug build. Total time of postThunkContents is 3.54%, 238ms.
This change reduces postTimeContents time to 50ms, making it to take 0.73% of Total CPU time.
So, instead of sorting the local part I suggest to just rebuild it.
That is what this patch does.
Differential revision: https://reviews.llvm.org/D45519
llvm-svn: 335583
* Move `REQUIRES:` line to the top
* llvm-mc ... -o %t -> llvm-mc ... -o %t.o
* Don't check "TEXT" "DATA" columns (they are bfd-style names that do
not fit into llvm well) in llvm-objdump output
llvm-svn: 335498
ICF is able to merge sections which relocations referring regular input sections
or mergeable sections, so it handles InputSection and MergeInputSection cases.
The following "return false" line which is executed in case of another type
of the sections is uncovered by our test cases:
https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp#L285
Patch fixes code coverage for this place.
llvm-svn: 335482
This test case check that ICF does not merge 2 sections which relocations
efer to symbols that live in sections of the different types
(regular input section and mergeable input sections in this case).
It covers the following line of code, which was uncovered previously:
https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp#L271
llvm-svn: 335475
Code is dead. We use only InputSections when building the list of
sections elegible for the ICF:
https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp#L439
And 'isEligible' filters out SyntheticSections as well for us.
That way the only Kind we have in the Sections vector is SectionBase::Regular,
so we do not need to check sections kind at all, it is always the same.
llvm-svn: 335460
This caused a lot of issues on the WebAssembly waterfall.
In particular, until with the signature of `main`. We
probably want a better solution for main before we re-land.
Reverts rL335192
llvm-svn: 335355
--verbose is not used to report ICF sections since r324755,
--print-icf-sections is used instead.
These tests were at fact disabled since that time.
llvm-svn: 335354
Change removes the excessive comparsion of
the relocation arrays sizes.
This code was dead, because at the higer level,
equalsConstant function contains the following check:
`A->NumRelocations != B->NumRelocations`
where NumRelocations contains the size of the relocations array.
So removed check did the same job twice.
This was found with use of code coverage analysis.
llvm-svn: 335346
During symbol resolution, emit warnings for function signature
mismatches. During GC, if any mismatched symbol is marked as live
then generate an error.
This means that we only error out if the mismatch is written to the
final output. i.e. if we would generate an invalid wasm file.
Differential Revision: https://reviews.llvm.org/D48394
llvm-svn: 335192
While building a Global Offset Table try to fill the primary GOT as much
as possible because the primary GOT can be accessed in the most
effective way. If it is not possible, try to fill the last GOT in the
multi-GOT list, and finally create a new GOT if both attempts failed.
llvm-svn: 335140
microMIPS 64-bit is unsupported by LLVM starting from r335057. But such
code can be generated by GCC. Mark failed test cases as XFAIL while
decide to drop microMIPS 64-bit support from LLD too or use binary
inputs for the test.
llvm-svn: 335059
Summary: For --wrap foo --wrap foo, bfd/gold wrap the symbol only once but LLD would rotate it twice.
Reviewers: ruiu, espindola
Subscribers: emaste, arichardson, mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D48298
llvm-svn: 334991
This is a follow up requested during post commit review for
"[lld] r333880 - [ELF] - Also use DW_AT_linkage_name when gathering information about variables for error messages."
It removes checking of the input objects since it is really excessive.
llvm-svn: 334946
Summary:
R_X86_64_GOTOFF64: S + A - GOT
R_X86_64_GOTPC{32,64}: GOT + A - P (R_GOTONLY_PC_FROM_END)
R_X86_64_GOTOFF64 should use R_GOTREL_FROM_END so that in conjunction with
R_X86_64_GOTPC{32,64}, the `GOT` term is neutralized. This also matches
the handling of R_386_GOTOFF (S + A - GOT).
Reviewers: ruiu, espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D48095
llvm-svn: 334672
Summary:
Any invocation of `clang -fuse-ld=lld` that results in a link command
on a macOS host currently fails, because the Darwin lld driver does not
recognize the `-lto_library` option that Clang passes it. Fix the error
by having the Darwin driver ignore the option.
The Clang driver's macOS toolchain is written such that it will always
pass the `-lto_library` option to the linker invocation on a macOS host.
And although the DarwinLdDriver is written to ignore any unknown arguments,
because `-lto_library` begins with `-l`, the DarwinLdDriver interprets it
as a library search command, for a library named "to_library". When the
DarwinLdDriver is unable to find a library specified via `-l`, it exits
with a hard error. This causes any invocation of `clang -fuse-ld=lld`
that results in a link command on a macOS host to fail with an error.
To fix the issue, I considered two alternatives:
1. Modify the Clang Darwin toolchain to only pass `-lto_library` if lld
is *not* being used. lld doesn't support LTO on Darwin anyway, so it
can't use the option. However, I opted against this because, if and
when lld *does* support LTO on Darwin, I'll have to make another
commit to Clang in order to get it to pass the option to lld again.
2. Modify the Darwin lld driver to ignore the `-lto_library` option.
Just in case users may take this to mean LTO is supported, I also
added a warning. If and when lld supports LTO on Darwin, the same
commit that adds support for this option can remove the warning.
Option (2) seemed better to me, and is the rationale behind this commit.
Test Plan: check-lld
Reviewers: ruiu, smeenai, pcc
Reviewed By: smeenai
Subscribers: JDevlieghere, pcc, mehdi_amini, inglorion, steven_wu, llvm-commits
Differential Revision: https://reviews.llvm.org/D47994
llvm-svn: 334641
WebAssembly depends on attributes.h which includes attributes.inc.
Unless cmake explicitly specifies this dependency, the .inc file
is sometimes generated after the build tries to use it.
Patch by Stella Stamenova
llvm-svn: 334581
`lld-link foo.lib /wholearchive:foo.lib` should work the same way as
`lld-link /wholearchive:foo.lib foo.lib`. Previously, /wholearchive in
the former case was ignored.
Differential Revision: https://reviews.llvm.org/D47565
llvm-svn: 334552
When running with linker GC (`-opt:ref`), defined imported symbols that
are referenced but then dropped by GC end up with their `Location`
member being nullptr, which means `getChunk()` returns nullptr for them
and attempting to call `getChunk()->getOutputSection()` causes a crash
from the nullptr dereference. Check for `getChunk()` being nullptr and
bail out early to avoid the crash.
Differential Revision: https://reviews.llvm.org/D48092
llvm-svn: 334548
R_X86_64_GOTOFF64 is a relocation type to set to a distance betwween
a symbol and the beginning of the .got section. Previously, we always
created a dynamic relocation for the relocation type even though it
can be resolved at link-time.
Creating a dynamic relocation for R_X86_64_GOTOFF64 caused link failure
for some programs that do have a relocation of the type in a .text
section, as text relocations are prohibited in most configurations.
Differential Revision: https://reviews.llvm.org/D48058
llvm-svn: 334534
This simplifies some code which had StringRefs to begin with, and
makes other code more complicated which had const char* to begin
with.
In the end, I think this makes for a more idiomatic and platform
agnostic API. Not all platforms launch process with null terminated
c-string arrays for the environment pointer and argv, but the api
was designed that way because it allowed easy pass-through for
posix-based platforms. There's a little additional overhead now
since on posix based platforms we'll be takign StringRefs which
were constructed from null terminated strings and then copying
them to null terminate them again, but from a readability and
usability standpoint of the API user, I think this API signature
is strictly better.
llvm-svn: 334518
Summary:
Previously LLD would not add any dynamic relocations and write a module
index of 1 which is not correct for the shared library case.
This can happen when a thread-local global variable is marked as local with
a version script. With this change I am now able to link all of the FreeBSD
base system for MIPS64 with LLD.
Differential Revision: https://reviews.llvm.org/D48002
llvm-svn: 334483
Summary:
Error handling in liblldCore and the Darwin toolchain prints to an
output stream. A TODO in the project explained that a diagnostics
interface resembling Clang's should be added.
For now, the simple diagnostics interface defined in liblldCommon seems
like an improvement. It prints colors when they're available, uses locks
for thread-safety, and abstracts away the `"error: "` and newline
literal strings that litter the Darwin toolchain code.
To use the liblldCommon error handler, a link dependency is added to
the liblldDriver library.
Test Plan:
1. check-lld
2. Invoke `ld64.lld -r` in a terminal that supports color output.
Confirm that "ld64.lld: error: -arch not specified and could not be inferred"
is output, and that the "error:" is colored red!
Reviewers: ruiu, smeenai
Reviewed By: ruiu
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D47998
llvm-svn: 334466
Patch adds support for most of the dynamic thread pointer based relocations
for local-dynamic tls. The HIGH and HIGHA versions are missing becuase they
are not supported by the llvm integrated assembler yet.
llvm-svn: 334465
In glibc libc.so.6, the multiple versions of sys_errlist share the same Symbol instance. When sys_errlist is copy relocated, we would replace SharedSymbol with Defined in the first iteration of the following loop:
for (SharedSymbol *Sym : getSymbolsAt<ELFT>(SS))
Then in the second iteration, we think the symbol (which has been changed to Defined) is still SharedSymbol and screw up (the address ends up in the `Size` field).
llvm-svn: 334432
Almost all entries inside MIPS GOT are referenced by signed 16-bit
index. Zero entry lies approximately in the middle of the GOT. So the
total number of GOT entries cannot exceed ~16384 for 32-bit architecture
and ~8192 for 64-bit architecture. This limitation makes impossible to
link rather large application like for example LLVM+Clang. There are two
workaround for this problem. The first one is using the -mxgot
compiler's flag. It enables using a 32-bit index to access GOT entries.
But each access requires two assembly instructions two load GOT entry
index to a register. Another workaround is multi-GOT. This patch
implements it.
Here is a brief description of multi-GOT for detailed one see the
following link https://dmz-portal.mips.com/wiki/MIPS_Multi_GOT.
If the sum of local, global and tls entries is less than 64K only single
got is enough. Otherwise, multi-got is created. Series of primary and
multiple secondary GOTs have the following layout:
```
- Primary GOT
Header
Local entries
Global entries
Relocation only entries
TLS entries
- Secondary GOT
Local entries
Global entries
TLS entries
...
```
All GOT entries required by relocations from a single input file
entirely belong to either primary or one of secondary GOTs. To reference
GOT entries each GOT has its own _gp value points to the "middle" of the
GOT. In the code this value loaded to the register which is used for GOT
access.
MIPS 32 function's prologue:
```
lui v0,0x0
0: R_MIPS_HI16 _gp_disp
addiu v0,v0,0
4: R_MIPS_LO16 _gp_disp
```
MIPS 64 function's prologue:
```
lui at,0x0
14: R_MIPS_GPREL16 main
```
Dynamic linker does not know anything about secondary GOTs and cannot
use a regular MIPS mechanism for GOT entries initialization. So we have
to use an approach accepted by other architectures and create dynamic
relocations R_MIPS_REL32 to initialize global entries (and local in case
of PIC code) in secondary GOTs. But ironically MIPS dynamic linker
requires GOT entries and correspondingly ordered dynamic symbol table
entries to deal with dynamic relocations. To handle this problem
relocation-only section in the primary GOT contains entries for all
symbols referenced in global parts of secondary GOTs. Although the sum
of local and normal global entries of the primary got should be less
than 64K, the size of the primary got (including relocation-only entries
can be greater than 64K, because parts of the primary got that overflow
the 64K limit are used only by the dynamic linker at dynamic link-time
and not by 16-bit gp-relative addressing at run-time.
The patch affects common LLD code in the following places:
- Added new hidden -mips-got-size flag. This flag required to set low
maximum size of a single GOT to be able to test the implementation using
small test cases.
- Added InputFile argument to the getRelocTargetVA function. The same
symbol referenced by GOT relocation from different input file might be
allocated in different GOT. So result of relocation depends on the file.
- Added new ctor to the DynamicReloc class. This constructor records
settings of dynamic relocation which used to adjust address of 64kb page
lies inside a specific output section.
With the patch LLD is able to link all LLVM+Clang+LLD applications and
libraries for MIPS 32/64 targets.
Differential revision: https://reviews.llvm.org/D31528
llvm-svn: 334390
This causes all symbols to be exported in the final wasm binary
even if they were not compiled with default visibility.
This feature is useful for the emscripten toolchain that has a
corresponding EXPORT_ALL feature which allows the JS code to
interact with all C function.
Differential Revision: https://reviews.llvm.org/D47806
llvm-svn: 334157
Summary:
When reporting an unsupported relocation type, let's also report the
file we encountered it in to aid diagnosis.
Reviewers: ruiu, rnk
Reviewed By: rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45911
llvm-svn: 334154
The original computation for shared object symbol alignment is wrong when
st_value equals 0. It is very unusual for dso symbols to have st_value equal 0.
But when it happens, it causes obscure run time bugs.
Differential Revision: https://reviews.llvm.org/D47602
llvm-svn: 334135
If building lld without x86 support, tests that require that support should
be treated as unsupported, not errors.
Tested using:
1. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64;X86'
make check-lld
=>
Expected Passes : 1406
Unsupported Tests : 287
2. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64'
make check-lld
=>
Expected Passes : 410
Unsupported Tests : 1283
Patch by Joel Jones
Differential Revision: https://reviews.llvm.org/D47748
llvm-svn: 334095
Previously, "-m is missing" error message is shown if you pass a
nonexistent file or don't pass any file at all to lld, as shown below:
$ ld.lld nonexistent.o
ld.lld: error: cannot open nonexistent.o: No such file or directory
ld.lld: error: target emulation unknown: -m or at least one .o file required
This patch eliminates the second error message because it's not related
and even inaccurate (you passed a .o file though it didn't exist).
llvm-svn: 334024
Currently, when LLD do a lookup for variables location, it uses DW_AT_name attribute.
That is not always enough.
Imagine code:
namespace A {
int bar = 0;
}
namespace Z {
int bar = 1;
}
int hoho;
In this case there are 3 variables and their debug attributes are following:
A::bar has: DW_AT_name [DW_FORM_string] ("bar") DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x00000006] = "_ZN1A3barE")
Z::bar has: DW_AT_name [DW_FORM_string] ("bar") DW_AT_linkage_name [DW_FORM_strp] ( .debug_str[0x0000003f] = "_ZN1Z3barE")
hoho has: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000004a] = "hoho") and has NO DW_AT_linkage_name attribute. Because it would be
the same as DW_AT_name and DWARF producers avoids emiting excessive data.
Hence LLD should also use DW_AT_linkage_name when it is available.
(currently, LLD fails to report location correctly because thinks that A::bar and Z::bar are the same things)
Differential revision: https://reviews.llvm.org/D47373
llvm-svn: 333880
Clang passes --plugin /path/to/LLVMgold.so to the linker when -flto is
passed. After r333607 we only ignore --plugin as a joined argument,
which means that the following argument (/path/to/LLVMgold.so) is
interpreted as an input file. This means that either every LTO'd
program ends up being linked with the gold plugin or we error out
if the plugin does not exist. The fix is to use Eq to ignore both
--plugin=foo and --plugin foo as before.
Differential Revision: https://reviews.llvm.org/D47657
llvm-svn: 333793
Since aliases don't actually need name, I removed it from Options.td
to keep the definitions concise.
Before:
-( Ignored for compatibility with GNU unless you pass --warn-backrefs
-) Ignored for compatibility with GNU unless you pass --warn-backrefs
--allow-multiple-definition Allow multiple definitions
--apply-dynamic-relocs Apply dynamic relocations to place
--as-needed Only set DT_NEEDED for shared libraries if used
--auxiliary=<value> Set DT_AUXILIARY field to the specified name
--Bdynamic Link against shared libraries
--Bshareable Build a shared object
...
After:
-( Alias for --start-group
-) Alias for --end-group
--allow-multiple-definition Allow multiple definitions
--apply-dynamic-relocs Apply dynamic relocations to place
--as-needed Only set DT_NEEDED for shared libraries if used
--auxiliary=<value> Set DT_AUXILIARY field to the specified name
--Bdynamic Link against shared libraries (default)
--Bshareable Alias for --shared
...
Differential Revision: https://reviews.llvm.org/D47588
llvm-svn: 333694
Summary:
After r333596, rpath-link no longer consumes the following argument, and
the path argument left by it confuses LLD.
Reviewers: espindola, ruiu
Reviewed By: ruiu
Subscribers: ruiu, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D47591
llvm-svn: 333686
Add support for the R_PPC64_GOT_TLSLD16 relocations used to build the address of
the tls_index struct used in local-dynamic tls.
Differential Revision: https://reviews.llvm.org/D47538
llvm-svn: 333681
getRelocTargetVA for R_TLSGD and R_TLSLD RelExprs calculate an offset from the
end of the got, so adjust the names to reflect this.
Differential Revision: https://reviews.llvm.org/D47379
llvm-svn: 333674
--push-state implemented in this patch saves the states of --as-needed,
--whole-archive and --static. It saves less number of flags than GNU linkers.
Since even GNU linkers save different flags, no one seems to care about the
details. In this patch, I tried to save the minimal number of flags to not
complicate the implementation and the siutation.
I'm not personally happy about adding the --{push,pop}-state flags though.
That options seem too hacky to me. However, gcc started using the options
since GCC 8 when GNU ld is available at the build time. Therefore, lld
is no longer a drop-in replacmenet for GNU linker for that machine
without supporting the flags.
Fixes https://bugs.llvm.org/show_bug.cgi?id=34567
Differential Revision: https://reviews.llvm.org/D47542
llvm-svn: 333646
Previously, we printed out two lines of help messages for `--foo bar`
and `--foo=bar` like this:
--soname=<value> Set DT_SONAME
--soname <value> Set DT_SONAME
--sort-section=<value> Specifies sections sorting rule when linkerscript is used
--sort-section <value> Specifies sections sorting rule when linkerscript is used
This change eliminates duplicate lines that doesn't contain `=` for such
options like this.
--soname=<value> Set DT_SONAME
--sort-section=<value> Specifies sections sorting rule when linkerscript is used
Differential Revision: https://reviews.llvm.org/D47558
llvm-svn: 333596
This should be correctly implied by the linker.
This also makes the tests slightly easier to maintain and compare
with the equivalent tests under for other platforms.
Differential Revision: https://reviews.llvm.org/D47513
llvm-svn: 333567
The comment only made sense a long time ago, when --thinlto-jobs was
tied with --lto-partitions. That was changed in r283817, but the test
wasn't updated at the same time. This patch does so.
llvm-svn: 333480
Peter Collingbourne suggested moving the switch to the top of the
function, so that all the code that cares about the output section for a
symbol is in the same place.
Differential Revision: https://reviews.llvm.org/D47497
llvm-svn: 333472
Rather than using a loop to compare symbol RVAs to the starting RVAs of
sections to determine which section a symbol belongs to, just get the
output section of a symbol directly via its chunk, and bail if the
symbol doesn't have an output section, which avoids having to hardcode
logic for handling dead symbols, CodeView symbols, etc. This was
suggested by Reid Kleckner; thank you.
This also fixes writing out symbol tables in the presence of RVA table
input sections (e.g. .sxdata and .gfids). Such sections aren't written
to the output file directly, so their RVA is 0, and the loop would thus
fail to find an output section for them, resulting in a segfault. Extend
some existing tests to cover this case.
Fixes PR37584.
Differential Revision: https://reviews.llvm.org/D47391
llvm-svn: 333450
Adds handling of all the relocation types for general-dynamic thread local
storage.
Differential Revision: https://reviews.llvm.org/D47325
llvm-svn: 333420
Recently an LLD test change was made that introduced the use of
llvm-bcanalyzer. This change adds the tool to the list of LLD test
dependencies.
Reviewed by: rdhindsa, ruiu
Patch by Owen Reynolds.
llvm-svn: 333277
PPC64 maintains a compiler managed got in the .toc section. When accessing a
global variable through got-indirect access, a .toc entry is created for the
variable. The relocation for the got-indirect access will refer to the .toc
section rather than the symbol that is actually accessed. The .toc entry
contains the address of the global variable. We evaluate the offset from
r2 (which is the TOC base) to the address of the toc entry for the global
variable. Currently, the .toc is not near the .got. This causes errors because
the offset from r2 to the toc section is too large. The linker needs to add
all the .toc input sections to the .got output section, merging the compiler
managed got with the linker got. This ensures that the offsets from the TOC
base to the toc entries are not too large.
This patch puts the .toc section right after the .got section.
Differential Revision: https://reviews.llvm.org/D45833
llvm-svn: 333199
A user program may enumerate sections named with a C identifier using
__start_* and __stop_* symbols. We cannot ICF any such sections because
that could change program semantics.
Differential Revision: https://reviews.llvm.org/D47242
llvm-svn: 333054
Note that this doesn't do the right thing in the case where there is
a linker script. We probably need to move output section assignment
before ICF to get the correct behaviour here.
Differential Revision: https://reviews.llvm.org/D47241
llvm-svn: 333052
When a symbol is GC'd it can still be references by relocations
in the debug sections, but such symbols are not assigned virtual
addresses.
This change adds a new global data symbol which gets GC'd but
should still appears in the output debug info, albeit with a 0
address.
Fixes 37555
Differential Revision: https://reviews.llvm.org/D47238
llvm-svn: 333047
There are only certain relocation types that can exist in the
wasm code section and they are all LEB types. Remove the dead
code for handling the other (I32) reloc types.
Differential Revision: https://reviews.llvm.org/D47226
llvm-svn: 333030
- Move some common code into Common/rrorHandler.cpp and
Common/Strings.h.
- Don't use `fatal` when incompatible bitcode files are
encountered.
- Rename NameRef variable to just Name
See D47162
Differential Revision: https://reviews.llvm.org/D47206
llvm-svn: 333021
* Gets function size field from right location
* Writes I32 values during compression
Patch by Yury Delendik
Differential Revision: https://reviews.llvm.org/D47204
llvm-svn: 333002
Previously, we had a loop to iterate over options starting with
`--plugin-opt=` and parse them by hand. But we can make OptTable
do that job for us.
Differential Revision: https://reviews.llvm.org/D47167
llvm-svn: 332935
This change adds the ability for lld to remove LEB padding from
code section. This effectively shrinks the size of the resulting
binary in proportion to the number of code relocations.
Since there will be a performance cost this is currently only active for
-O1 and above. Some toolchains may instead want to perform this
compression as a post linker step (for example running a binary through
binaryen will automatically compress these values).
I imagine we might want to make this the default in the future.
Differential Revision: https://reviews.llvm.org/D46416
llvm-svn: 332783
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47032
llvm-svn: 332757
_init_array_start/end are placed at 0 if no ".init_array" presents,
this causes .text relocation against them become more prone to overflow.
This CL sets ".init_array" address to that of ".text" to mitigate the situation.
Review: https://reviews.llvm.org/D46200
llvm-svn: 332688
Previously we emitted 20-byte SHA1 hashes. This is overkill
for identifying debug info records, and has the negative side
effect of making object files bigger and links slower. By
using only the last 8 bytes of a SHA1, we get smaller object
files and ~10% faster links.
This modifies the format of the .debug$H section by adding a new
value for the hash algorithm field, so that the linker will still
work when its object files have an old format.
Differential Revision: https://reviews.llvm.org/D46855
llvm-svn: 332669
The prefix includes type kind, which is important to preserve. Two
different type leafs can easily have the same interior record contents
as another type.
We ran into this issue in PR37492 where a bitfield type record collided
with a const modifier record. Their contents were bitwise identical, but
their kinds were different.
llvm-svn: 332664
Patch by Mark Kettenis.
Make ALIGN work in linker scripts used with the -r option. This works in
GNU ld (ld.bfd) and is used to generate the "random gap" object for
linking the OpenBSD kernel.
Differential Revision: https://reviews.llvm.org/D46839
llvm-svn: 332656
Previously we would always write a hash of the binary into the
PE file, for reproducible builds. This breaks AppCompat, which
is a feature of Windows that relies on the timestamp in the PE
header being set to a real value (or at the very least, a value
that satisfies certain properties).
To address this, we put the old behavior of writing the hash
behind the /Brepro flag, which mimics MSVC linker behavior. We
also match MSVC default behavior, which is to write an actual
timestamp to the PE header. Finally, we add the /TIMESTAMP
option (an lld extension) so that the user can specify the exact
value to be used in case he/she manually constructs a value which
is both reproducible and satisfies AppCompat.
Differential Revision: https://reviews.llvm.org/D46966
llvm-svn: 332613
Currently, LLD marks all non-allocatable sections except SHF_REL[A] as Live
when doing GC.
This can be a reason of the crash when SHF_LINK_ORDER sections
are involved, because their parents can be dead.
We should do GC for them correctly. The patch implements it.
Differential revision: https://reviews.llvm.org/D46880
llvm-svn: 332589
Fixes: lld: warning: unexpected existing value for R_WEBASSEMBLY_FUNCTION_OFFSET_I32: existing=839 expected=838
The existing solution is trying to erroneously recover correct offset of
the function code from the body (which is not a function segment that
includes its size, locals, and code).
The D46763 is trying to maintain the offset of the function code
allowing properly calculate the new relocation entry.
Patch by Yury Delendik
Differential Revision: https://reviews.llvm.org/D46765
llvm-svn: 332412
This CL places .dynsym and .dynstr at the beginning of SHF_ALLOC
sections. We do this to mitigate the possibility that huge .dynsym and
.dynstr sections placed between ro-data and text sections cause
relocation overflow.
Differential Revision: https://reviews.llvm.org/D45788
llvm-svn: 332374
Summary: This is similar to D46290 D46320.
Reviewers: ruiu, grimar
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D46861
llvm-svn: 332372
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
Differential Revision: https://reviews.llvm.org/D44977
llvm-svn: 332351
The --keep-unique <symbol> option is taken from gold. The intention is that
<symbol> will be prevented from being folded by ICF. Although not
specifically mentioned in the documentation <symbol> only matches
global symbols, with a warning if the symbol is not found.
The implementation finds the Section defining <symbol> and removes it from
the set of sections considered for ICF.
Differential Revision: https://reviews.llvm.org/D46755
llvm-svn: 332332
This allows producing pdb debug info. This is an LLD specific option
since GCC and GNU binutils doesn't support the PDB file format.
Differential Revision: https://reviews.llvm.org/D46796
llvm-svn: 332327
Since we a no longer using this function for the wasm start
section we don't actually care what its signature is.
Differential Revision: https://reviews.llvm.org/D46594
llvm-svn: 332308
The relocation R_PPC64_REL64 should return R_PC for getRelExpr since it
computes S + A - P.
Differential Revision: https://reviews.llvm.org/D46766
llvm-svn: 332259
The relocation R_PPC64_REL32 should return R_PC for getRelExpr since it
computes S + A - P.
Differential Revision: https://reviews.llvm.org/D46586
llvm-svn: 332252
If a symbol with an undefined version in a DSO is not going to be
exported into the dynamic symbol table then do not give an error message
for the missing version. This can happen with the --exclude-libs option
which implicitly gives all symbols in a static library the local version.
This matches the behavior of ld.gold and is exploited by the Bionic
dynamic linker on Arm.
Differential Revision: https://reviews.llvm.org/D43126
llvm-svn: 332224
This is needed to avoid merging two functions with identical
instructions but different xdata. It also reduces binary size by
deduplicating identical pdata sections.
Fixes PR35337.
Differential Revision: https://reviews.llvm.org/D46672
llvm-svn: 332169
We discovered (crbug.com/838449#c24) that string tail merging can
negatively affect compressed binary size, so provide a flag to turn
it off for users who care more about compressed size than uncompressed
size.
Differential Revision: https://reviews.llvm.org/D46780
llvm-svn: 332149
Both R_PPC_CALL and R_PPC_CALL_PLT Exprs map to the R_PPC64_REL24 relocation
which has the form Sym + addend - P.
Differential Revision: https://reviews.llvm.org/D46654
llvm-svn: 332127
Summary:
Suppose we visit symbols in this order:
1. weak definition of foo in a lazy object
2. reference of foo
3 (optional). definition of foo
bfd/gold allows 123 but not 12.
Current --warn-backrefs implementation will report both cases as a backward reference. With this change, both 123 (intended) and 12 (unintended) are allowed. The usage of weak definitions usually imply there are also global definitions, so the trade-off is justified.
Reviewers: ruiu, espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D46624
llvm-svn: 332061
Rui Ueyama