As was mentioned in comments for D45158,
isPicRel's name does not make much sense,
because what this method does is checks if
we need to create the dynamic relocation or not.
Instead of renaming it to something different,
we can 'isPicRel' completely.
We can reuse the getDynRel method.
They are logically very close, getDynRel can just return
R_*_NONE in case no dynamic relocation should be produced
and that would simplify things and avoid functionality
correlation/duplication with 'isPicRel'.
The patch does this change.
Differential revision: https://reviews.llvm.org/D45248
llvm-svn: 329275
Currently, LLD print symbol assignment commands to the map file,
but it does not do that for assignments that are outside of the section
descriptions. Such assignments can affect the layout though.
The patch implements the following:
* Teaches LLD to print symbol assignments outside of section declaration.
* Teaches LLD to print PROVIDE/HIDDEN/PROVIDE hidden commands.
In case when symbol is not provided, nothing will be printed.
Differential revision: https://reviews.llvm.org/D44894
llvm-svn: 329272
Currently, LLD prints VA, but not LMA in a map file.
It seems can be useful to print both to reveal layout
details and patch implements it.
Differential revision: https://reviews.llvm.org/D44899
llvm-svn: 329271
One place where this seems to matter is to make sure the .rsrc section comes
after .text. The Win32 UpdateResource() function can change the contents of
.rsrc. It will move the sections that come after, but if .text gets moved, the
entry point header will not get updated and the executable breaks. This was
found by a test in Chromium.
Differential Revision: https://reviews.llvm.org/D45260
llvm-svn: 329221
We were ignoring the addend if the piece was dead. I don't expect this
to make a difference in any real world situations, but it is simpler
anyway.
llvm-svn: 329219
isPicRel is used to check if we want to create the dynamic relocations.
Not all of the dynamic relocations we create are passing through this
check, but those that are, probably better be whitelisted.
Differential revision: https://reviews.llvm.org/D45252
llvm-svn: 329203
In the lld perf builder r328686 had a negative impact in
stalled-cycles-frontend. Somehow that stat is not showing on my
machine, but the attached patch shows an improvement on cache-misses,
which is probably a reasonable proxy.
My working theory is that given a large input the pieces vector is out
of cache by the time initOffsetMap runs.
Both finalizeContents implementation have a convenient location for
initializing the OffsetMap, so this seems the best solution.
llvm-svn: 329117
Summary:
r328610 fixed a data race in the COFF linker. This change makes a
similar fix to the ELF linker.
Reviewers: ruiu, pcc, rnk
Reviewed By: ruiu
Subscribers: emaste, llvm-commits, arichardson
Differential Revision: https://reviews.llvm.org/D45192
llvm-svn: 329088
Added checks to test that we do not produce
output where VA of sections overruns the address
space available.
Differential revision: https://reviews.llvm.org/D43820
llvm-svn: 329063
This fixes PR36927.
The issue is next. Imagine we have -Ttext 0x7c and code below.
.code16
.global _start
_start:
movb $_start+0x83,%ah
So we have R_386_8 relocation and _start at 0x7C.
Addend is 0x83 == 131. We will sign extend it to 0xffffffffffffff83.
Now, 0xffffffffffffff83 + 0x7c gives us 0xFFFFFFFFFFFFFFFF.
Techically 0x83 + 0x7c == 0xFF, we do not exceed 1 byte value, but
currently LLD errors out, because we use checkUInt<8>.
Let's try to use checkInt<8> now and the following code to see if it can help (no):
main.s:
.byte foo
input.s:
.globl foo
.hidden foo
foo = 0xff
Here, foo is 0xFF. And addend is 0x0. Final value is 0x00000000000000FF.
Again, it fits one byte well, but with checkInt<8>,
we would error out it, so we can't use it.
What we want to do is to check that the result fits 1 byte well.
Patch changes the check to checkIntUInt to fix the issue.
Differential revision: https://reviews.llvm.org/D45051
llvm-svn: 329061
Having 8/16 bits dynamic relocations is incorrect.
Both gold and bfd (built from latest sources) disallow
that too.
Differential revision: https://reviews.llvm.org/D45158
llvm-svn: 329059
OffsetMap maps to a SectionPiece index, but we were not taking
advantage of that in getSectionPiece.
With this patch both getOffset and getSectionPiece use OffsetMap and
the binary search is moved to findSectionPiece.
llvm-svn: 329044
They are to pull out an object file for a symbol, but for a historical
reason the code is written in two separate functions. This patch
merges them.
llvm-svn: 329039
The Plt relative relocations are R_PPC64_JMP_SLOT in the V2 abi, and we only
reserve 2 double words instead of 3 at the start of the array of PLT entries for
lazy linking.
Differential Revision: https://reviews.llvm.org/D44951
llvm-svn: 329006
Adds a simple test for accessing a local global variable in the ElfV2 abi.
Checks that the toc base used is the expected offset from the .TOC. symbol,
and that the offsets for the global are calculated relative to the toc base.
llvm-svn: 328982
It generally does not matter much where we place sections ordered
by --symbol-ordering-file relative to other sections. But if the
ordered sections are hot (which is the case already for some users
of --symbol-ordering-file, and is increasingly more likely to be
the case once profile-guided section layout lands) and the target
has limited-range branches, it is beneficial to place the ordered
sections in the middle of the output section in order to decrease
the likelihood that a range extension thunk will be required to call
a hot function from a cold function or vice versa.
That is what this patch does. After D44966 it reduces the size of
Chromium for Android's .text section by 60KB.
Differential Revision: https://reviews.llvm.org/D44969
llvm-svn: 328905
Now that we have the ability to create short thunks, it is beneficial
for thunk sections to be surrounded by ThunkSectionSpacing bytes
of code on both sides in order to increase the likelihood that the
distance from the thunk to the target will be sufficiently small to
allow for the creation of a short thunk. This is currently the case
for most thunks that we create, except for the last one, which could,
depending on the size of the output section, potentially appear near
the end and therefore have a relatively small amount of code after it.
This patch moves the last thunk section to ThunkSectionSpacing bytes
before the end of the output section, as long as the section is larger
than 2*ThunkSectionSpacing bytes. It reduces the size of Chromium
for Android's .text section by 32KB.
Differential Revision: https://reviews.llvm.org/D44966
llvm-svn: 328889
/FIXED:NO is always the default, so that part needs no work.
Also test the interaction of /ORDER: with /INCREMENTAL.
https://reviews.llvm.org/D45091
llvm-svn: 328877
As of rL215127, FileCheck has an -allow-empty flag,
so this could be used instead of writing a dummy line.
But it looks like the log is never empty now, so not
even that is needed.
llvm-svn: 328862
I tried a few different designs to find a way to implement it without
too much hassle and settled down with this. Unlike before, object files
given as arguments for --just-symbols are handled as object files, with
an exception that their section tables are handled as if they were all
null.
Differential Revision: https://reviews.llvm.org/D42025
llvm-svn: 328852
A short thunk uses a direct branch (b or b.w) instruction, and is used
when the target has the same thumbness as the thunk and is within
direct branch range (32MB for ARM, 16MB for Thumb-2). Reduces the
size of Chromium for Android's .text section by around 160KB.
Differential Revision: https://reviews.llvm.org/D44963
llvm-svn: 328846
There are two FPMs in an MSF file, the idea being that for
incremental updates you can write to the alternate one and then
atomically swap them on commit. LLVM defaulted to using FPM1
on the first commit, but this differs from Microsoft's behavior
which is to default to using FPM2 on the first commit. To
eliminate some byte-level file differences, this patch changes
LLVM's default to also be FPM2.
Additionally, LLVM was trying to be "smart" about marking FPM
pages allocated. In addition to marking every page belonging
to the alternate FPM as unallocated, LLVM also marked pages at
the end of the main FPM which were not needed as unallocated.
In order to match the behavior of Microsoft-generated PDBs, we
now always mark every FPM block as allocated, regardless of
whether it is in the main FPM or the alt FPM, and regardless of
whether or not it describes blocks which are actually in the file.
This has the side benefit of simplifying our code.
llvm-svn: 328812
This patch fixes an issue introduced in r328810 which made the algorithm
to always run the loop O(n^2) times, though we can break early. The
output remains the same.
llvm-svn: 328811
The PLT retpoline support for X86 and X86_64 did not include the padding
when writing the header and entries. This issue was revealed when linker
scripts were used, as this disables the built-in behaviour of filling
the last page of executable segments with trap instructions. This
particular behaviour was hiding the missing padding.
Added retpoline tests with linker scripts.
Differential Revision: https://reviews.llvm.org/D44682
llvm-svn: 328777
NonLocal is technically more accurate, but we already use the term
"Global" to specify the non-local part of the symbol table, and
Local <-> Global is easier to digest.
llvm-svn: 328740
This fixes pr36623.
The problem is that we have to parse versions out of names before LTO
so that LTO can use that information.
When we get the LTO produced .o files, we replace the previous symbols
with the LTO produced ones, but they still have @ in their names.
We could just trim the name directly, but calling parseSymbolVersion
to do it is simpler.
llvm-svn: 328738
Also make certain Thunk methods non-const as this will be required for
an upcoming change.
Differential Revision: https://reviews.llvm.org/D44961
llvm-svn: 328732
This enables callback-style programming where the JavaScript environment
can call back into the Wasm environment using a function pointer
received from the module.
Differential Revision: https://reviews.llvm.org/D44427
llvm-svn: 328643
Some tools (dwarfdump for example) get confused by the current -O0 -r
output since it has multiple copies of .debug_str.
We cannot just merge sections with the same name as they can have
different sh_entsize.
We could have duplicated logic for merging sections based on name and
sh_entsize, but it seems better to just use the existing logic by
enabling optimizations.
llvm-svn: 328640
The Data member of synthetic section's is not valid and empty. The Data
member is required to be valid by ICF as it is used by ICF to determine
the equality of section contents. Therefore, exclude synthetic sections
from ICF.
Fixes bug PR36910.
Differential Revision: https://reviews.llvm.org/D44923
llvm-svn: 328624
SharedFile::parseRest function grew organically and got a bit hard to
understand. This patch refactor it. This patch also adds comments.
Differential Revision: https://reviews.llvm.org/D44860
llvm-svn: 328579
When the target saves ElfSym::GlobalOffsetTable in the .got rather than
.got.plt, Target->GotHeaderEntriesNum states the number of extra entries
required in the .got. Rather than having to add Target->GotHeaderEntriesNum to
NumEntries in every function which refers to NumEntries, this patch changes the
initial value of NumEntries in the constructor.
Differential Revision: https://reviews.llvm.org/D44744
llvm-svn: 328559
Currently, we might have a bug with scripts like below:
.foo : ALIGN(8)
{
*(.foo)
} > ram
because do not expand the memory region when doing ALIGN.
This might result in file range overlaps. The patch fixes the issue.
Differential revision: https://reviews.llvm.org/D44730
llvm-svn: 328479
Currently when we build input sections list in linker script
we ignore all rel[a] sections. That was done to support
scripts like .rela.dyn : { *(.rela.data) } for emit relocs.
Though as a result following scripts were also silently ignored:
/DISCARD/ : { *(.rela.plt)
/DISCARD/ : { *(.rela.dyn)
and we produced output with this sections. That is not ideal.
The solution this patch suggests is simple: do not ignore synthetic
rel[a] sections. That way we can enable common discarding logic
for them and report a proper error.
Differential revision: https://reviews.llvm.org/D41640
llvm-svn: 328419
Previously, we used 0 as an alias for VER_NDX_GLOBAL and had a dummy
entry in SharedFile::Verdefs so that the access to the array is within
its boundary. But that's not straightforwad. We can just stop doing both.
llvm-svn: 328401
Since SectionBase::getOutputSection handles ICF replaces and
SectionBase::getOffset was handling it in some cases, it is more
consistent to have getOffset always handle it.
llvm-svn: 328391
This was reverted several times due to what ultimately turned out
to be incompatibilities in our serialized hash table format.
Several changes went in prior to this to fix those issues since
they were more fundamental and independent of supporting injected
sources, so now that those are fixed this change should hopefully
pass.
llvm-svn: 328363
When investigating bugs in PDB generation, the first step is
often to do the same link with link.exe and then compare PDBs.
But comparing PDBs is hard because two completely different byte
sequences can both be correct, so it hampers the investigation when
you also have to spend time figuring out not just which bytes are
different, but also if the difference is meaningful.
This patch fixes a couple of cases related to string table emission,
hash table emission, and the order in which we emit strings that
makes more of our bytes the same as the bytes generated by MS PDBs.
Differential Revision: https://reviews.llvm.org/D44810
llvm-svn: 328348
When looking for the output section and the output offset the
expectation was that the caller had looked at Repl. That works fine
for InputSections, but in the case of MergeInputSections the caller
doesn't have the section that is actually replaced.
The original testcase was failing because getOutputSection was
returning null. The slightly extended testcase also checks that
getOffset also checks Repl.
I will send a refactoring separetelly.
llvm-svn: 328332
This fixes PR36367 which is about segfault when --emit-relocs is
used together with .eh_frame sections which happens because
of reordering of regular and .rel[a] sections.
Path changes loop that iterates over input sections to create
relocation target sections first.
Differential revision: https://reviews.llvm.org/D44679
llvm-svn: 328299
Eugene Leviant