Sections that will be mapped at runtime will only have the short
section name available, since the string table it points into isn't
mapped. Therefore prefer truncating those names over writing a
long name that is unavailable at runtime.
This allows libunwind to find the .eh_frame section at runtime even
if the module was built with debug info enabled.
Differential Revision: https://reviews.llvm.org/D40025
llvm-svn: 318391
Summary:
We previously assumed that all SafeSEH handlers are
DefinedRegular symbols. This is not the case for handlers defined in
DLLs. As a result, we were failing to emit entries in the SafeSEH
table for those handlers. This change fixes that.
Fixes PR35324.
Reviewers: rnk, ruiu
Reviewed By: rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40102
llvm-svn: 318364
Even if we don't actually write any string table contents, the
4 byte size for the string table will always be written. Make
sure we accommodate for this in the file size. Since this size
is aligned up, this would seldom be an issue in practice.
Differential Revision: https://reviews.llvm.org/D39891
llvm-svn: 318284
Summary:
__safe_se_handler_base should be either absolute 0 (when no SafeSEH
table is present), or relative to the image base (when the table is
present). An earlier change inadvertedly made the symbol absolute in
both cases, leading to the SafeSEH table not being locatble at run
time. This change fixes that and updates the safeseh test to check for
the presence of the relocation.
Reviewers: rnk, ruiu
Reviewed By: ruiu
Subscribers: ruiu, llvm-commits
Differential Revision: https://reviews.llvm.org/D39765
llvm-svn: 317635
Now that we have only SymbolBody as the symbol class. So, "SymbolBody"
is a bit strange name now. This is a mechanical change generated by
perl -i -pe s/SymbolBody/Symbol/g $(git grep -l SymbolBody lld/ELF lld/COFF)
nd clang-format-diff.
Differential Revision: https://reviews.llvm.org/D39459
llvm-svn: 317370
IIUC, SizeOfImage is the distance from the end of the last section to
the image base, rounded up to the page size. So the previous code is
wrong.
Should fix https://bugs.llvm.org/show_bug.cgi?id=34949
(It is nice to know that lld is already being used to create Putty
distribution binaries.)
llvm-svn: 316626
Summary:
The COFF linker and the ELF linker have long had similar but separate
Error.h and Error.cpp files to implement error handling. This change
introduces new error handling code in Common/ErrorHandler.h, changes the
COFF and ELF linkers to use it, and removes the old, separate
implementations.
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: smeenai, jyknight, emaste, sdardis, nemanjai, nhaehnle, mgorny, javed.absar, kbarton, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D39259
llvm-svn: 316624
Sections are limited to 4 GiB. Error out early if a section exceeds this
size, rather than overflowing the section size and getting confusing
assertion failures/segfaults later.
Differential Revision: https://reviews.llvm.org/D38005
llvm-svn: 313699
r303378 was submitted because r303374 (Merge IAT and ILT) made lld's
output incompatible with the Binding feature. Now that r303374 was
reverted, we do not need to keep this change.
Pointed out by pcc.
llvm-svn: 313414
Various classes have `Symtab` member variables even though we have
lld::coff::Symtab variable because previous attempts to make COFF lld's
internal structure resemble to ELF's was incomplete. This patch finishes
that job by removing member variables.
llvm-svn: 311938
I'm explicitly ignoring the warning by casting to void instead of
deleting the local assignment, because it's confusing to see a
function that fails when its return value evaluates to true.
But when you see that it's a std::error_code, it makes more sense.
llvm-svn: 310965
Previously, our algorithm to compute a build id involved hashing the
executable and storing that as the GUID in the CV Debug Record chunk,
and setting the age to 1.
This breaks down in one very obvious case: a user adds some newlines to
a file, rebuilds, but changes nothing else. This causes new line
information and new file checksums to get written to the PDB, meaning
that the debug info is different, but the generated code would be the
same, so we would write the same build over again with an age of 1.
Anyone using a symbol cache would have a problem now, because the
debugger would open the executable, look at the age and guid, find a
matching PDB in the symbol cache and then load it. It would never copy
the new PDB to the symbol cache.
This patch implements the canonical Windows algorithm for updating
a build id, which is to check the existing executable first, and
re-use an existing GUID while bumping the age if it already
exists.
Differential Revision: https://reviews.llvm.org/D36758
llvm-svn: 310961
Summary:
PDB section contributions are supposed to use output section indices and
offsets, not input section indices and offsets.
This allows the debugger to look up the index of the module that it
should look up in the modules stream for symbol information. With this
change, windbg can now find line tables, but it still cannot print local
variables.
Fixes PR34048
Reviewers: zturner
Subscribers: hiraditya, ruiu, llvm-commits
Differential Revision: https://reviews.llvm.org/D36285
llvm-svn: 309987
In order to get dbghelp to load our pdb, we have to fill in the
PointerToRawData field as well as the AddressOfRawData field. One is the
file offset and the other is the RVA.
llvm-svn: 309900
Summary:
MSVC link.exe records all external symbol names in the publics stream.
It provides similar functionality to an ELF .symtab.
Reviewers: zturner, ruiu
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D35871
llvm-svn: 309303
Summary:
In order to do this without switching on the symbol kind multiple times,
I created Defined::getChunkAndOffset and use that instead of
SymbolBody::getRVA in the inner relocation loop.
Now we get the symbol's chunk before switching over relocation types, so
we can test if it has been discarded outside the inner relocation type
switch. This also simplifies application of section relative
relocations. Previously we would switch on symbol kind to compute the
RVA, then the relocation type, and then the symbol kind again to get the
output section so we could subtract that from the symbol RVA. Now we
*always* have an OutputSection, so applying SECREL and SECTION
relocations isn't as much of a special case.
I'm still not quite happy with the cleanliness of this code. I'm not
sure what offsets and bases we should be using during the relocation
processing loop: VA, RVA, or OutputSectionOffset.
Reviewers: ruiu, pcc
Reviewed By: ruiu
Subscribers: majnemer, inglorion, llvm-commits, aprantl
Differential Revision: https://reviews.llvm.org/D34650
llvm-svn: 306566
Summary:
They do the obvious thing: provide the section index of .bss and the
offset of the symbol in .bss.
Reviewers: ruiu
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34628
llvm-svn: 306304
Summary:
The main change is that we can have SECREL and SECTION relocations
against ___safe_se_handler_table, which is important for handling the
debug info in the MSVCRT.
Previously we were using DefinedRelative for __safe_se_handler_table and
__ImageBase, and after we implement CFGuard, we plan to extend it to
handle __guard_fids_table, __guard_longjmp_table, and more. However,
DefinedRelative is really only suitable for implementing __ImageBase,
because it lacks a Chunk, which you need in order to figure out the
output section index and output section offset when resolving SECREl and
SECTION relocations.
This change renames DefinedRelative to DefinedSynthetic and gives it a
Chunk. One wart is that __ImageBase doesn't have a chunk. It points to
the PE header, effectively. We could split DefinedRelative and
DefinedSynthetic if we think that's cleaner and creates fewer special
cases.
I also added safeseh.s, which checks that we don't emit a safe seh table
entries pointing to garbage collected handlers and that we don't emit a
table at all when there are no handlers.
Reviewers: ruiu
Reviewed By: ruiu
Subscribers: inglorion, pcc, llvm-commits, aprantl
Differential Revision: https://reviews.llvm.org/D34577
llvm-svn: 306293
Summary:
For SECTION relocations against absolute symbols, MSVC emits the largest
output section index plus one. I've implemented that by threading a
global variable through DefinedAbsolute that is filled in by the Writer.
A more library-oriented approach would be to thread the Writer through
Chunk::writeTo and SectionChunk::applyRel*, but Rui seems to prefer
doing it this way.
MSVC rejects SECREL relocations against absolute symbols, but only when
the relocation is in a real output section. When the relocation is in a
CodeView debug info section destined for the PDB, it seems that this
relocation error is suppressed, and absolute symbols become zeros in the
object file. This is easily implemented by checking the input section
from which we're applying relocations.
This should fix errors about __safe_se_handler_table and
__guard_fids_table when linking the CRT and generating a PDB.
Reviewers: ruiu
Subscribers: aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D34541
llvm-svn: 306071
This works around a strange interaction with Authenticode signatures,
in which a signed PE executable with {Major,Minor}LinkerVersion = 0.0
fails to validate on Windows 7 (but is OK on Windows 10). Setting the
linker version to 14.0 (which is what VS2015 outputs) makes it work
again.
Patch by Simon Tatham <simon.tatham@arm.com>.
llvm-svn: 305929
Summary:
Previously we didn't add debug info chunks to the SparseChunks array, so
they didn't participate in section GC. Now we do.
Reviewers: ruiu
Subscribers: aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D34356
llvm-svn: 305811
Summary:
This is a first step towards getting line info to show up in VS and
windbg. So far, only llvm-pdbutil can parse the PDBs that we produce.
cvdump doesn't like something about our file checksum tables. I'll have
to dig into that next.
This patch adds a new DebugSubsectionRecordBuilder which takes bytes
directly from some other producer, such as a linker, and sticks it into
the PDB. Line tables only need to be relocated. No data needs to be
rewritten.
File checksums and string tables, on the other hand, need to be re-done.
Reviewers: zturner, ruiu
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D34257
llvm-svn: 305713
If you pass /delayload:<dllname> to the COFF linker, it creates thunks
so that DLLs are loaded when they are used for the first time instead of
load-time.
This mechanism do not work for data symbols as there's no way to trap
acccesses to data imported from DLLs. (Technically, I think if we do not
initially map dllimport tables in memory, we could actually trap accesses
and delay-load data symbols, but that's not what Windows do.)
This patch is to report an error when you try to delay-load data symbols.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33106
Differential Revision: https://reviews.llvm.org/D33557
llvm-svn: 303890
This is a different implementation than r303225 (which was reverted
in r303270, re-submitted in r303304 and then re-reverted in r303527).
In the previous patch, I tried to add Live bit to each dllimported
symbol. It turned out that it didn't work with "oldnames.lib" which
contains a lot of weak aliases to dllimported symbols.
The way we handle weak aliases is to check if undefined symbols
can be resolved using weak aliases, and if so, memcpy the Defined
symbols to weak Undefined symbols, so that any references to weak
aliases automatically see defined symbols instead of undefined ones.
This memcpy happens before MarkLive kicks in.
That means we may have multiple copies of dllimported symbols. So
turning on one instance's Live bit is not enough.
This patch moves the Live bit to dllimport file. Since multiple
copies of dllsymbols still point to the same file, we can use it as the
central repository to keep track of liveness.
Differential Revision: https://reviews.llvm.org/D33520
llvm-svn: 303814
This reverts commit r303304 because it looks like the change
introduced a crash bug. At least after that change, LLD with thinlto
crashes when linking Chromium.
llvm-svn: 303527
Our output is not compatible with the Binding feature, so make it
explicit that.
Differential Revision: https://reviews.llvm.org/D33336
llvm-svn: 303378
We've been using make<> to allocate new objects in ELF. We have
the same function in COFF, but we didn't use it widely due to
negligence. This patch uses the function in COFF to close the gap
between ELF and COFF.
llvm-svn: 303357
When /DEBUG is not specified, /PDB should be ignored. When
/DEBUG is specified, a PDB should be output regardless of
whether or not /PDB is specified. /PDB just overrides the
default name.
This patch implements this behavior, and adds some tests, while
also removing a dead option /DEBUGPDB which was unused in any
code.
Differential Revision: https://reviews.llvm.org/D33302
llvm-svn: 303352
This reverts re-submits r303225 which was reverted in r303270 because it
broke the sanitizer-windows bot.
The reason of the failure is that we were writing dead symbols to the
symbol table. I fixed the issue.
llvm-svn: 303304
and follow-up r303226 "Fix Windows buildbots."
This broke the sanitizer-windows buildbot.
> Previously, the garbage collector (enabled by default or by explicitly
> passing /opt:ref) did not kill dllimported symbols. As a result,
> dllimported symbols could be added to resulting executables' dllimport
> list even if no one was actually using them.
>
> This patch implements dllexported symbol garbage collection. Just like
> COMDAT sections, dllimported symbols now have Live bits to manage their
> liveness, and MarkLive marks reachable dllimported symbols.
>
> Fixes https://bugs.llvm.org/show_bug.cgi?id=32950
>
> Reviewers: pcc
>
> Subscribers: llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D33264
llvm-svn: 303270
Summary:
Previously, the garbage collector (enabled by default or by explicitly
passing /opt:ref) did not kill dllimported symbols. As a result,
dllimported symbols could be added to resulting executables' dllimport
list even if no one was actually using them.
This patch implements dllexported symbol garbage collection. Just like
COMDAT sections, dllimported symbols now have Live bits to manage their
liveness, and MarkLive marks reachable dllimported symbols.
Fixes https://bugs.llvm.org/show_bug.cgi?id=32950
Reviewers: pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33264
llvm-svn: 303225
The /appcontainer flag indicates that the module may only be used inside
an application container (for isolation). This has been supported by
link.exe since Windows 8.0. It sets an additional bit in the PE DLL
Characteristics flag to indicate the behavioural change.
llvm-svn: 299728
Martin Storsjo