This makes a difference when linking executables with delay loaded
libraries for arm32; the delay loader implementation can load data from
the registry with instructions that assume alignment.
This issue does not show up when linking in MinGW mode, because a
PseudoRelocTableChunk gets injected, which also sets alignment, even if
the chunk itself is empty.
The loader can usually handle an unaligned import dir chunk, but It's not
optimal and it's not what MSVC link.exe does.
Windows refuses to load ARM64X binaries with unaligned import directory.
aarch64 and arm64ec imports are shared in such binaries as much as
possible. As long as they use the same set of functions from given import
directory, both the directory and import addresses chunk are just shared.
When used set of functions differs, ARM64X dynamic relocations are used
to modify import dir to point to different names and import addresses for
its EC view. I suspect that the loader expects some alignment on ARM64X
dynamic relocation offset and may not be the case when relocated import
dir is not aligned.
MSVC link.exe allows overriding exports on the cmd-line with exports seen in OBJ directives. The typical case is what is described in #62329.
Before this patch, trying to override an export with `/export` or `/def` would generate a duplicate warning. This patches tries to replicate the MSVC behavior. A second override on the cmd-line would still generate the warning.
There's still a case which we don't cover: MSVC link.exe is able to demangle an exported OBJ directive function, and match it with a unmangled export function in a .def file. In the meanwhile, one can use the mangled export in the .def to cover that case.
This fixes#62329
Differential revision: https://reviews.llvm.org/D149611
For each symbol in a /delayloaded library, lld injects a small piece of
code to handle the symbol lazy loading. This code doesn't have unwind
information, which may be troublesome.
Provide these information for AMD64.
Thanks to Yannis Juglaret <yjuglaret@mozilla.com> for contributing the
unwinding info and for his support while crafting this patch.
Fix#59639
Differential Revision: https://reviews.llvm.org/D141691
This reverts commit 7370ff624d217b0f8f7512ca5b651a9b8095a411.
(and 47fb8ae2f9a4075de05433ef24f459b6befd1730).
This commit broke the symbol type in import libraries generated
for mingw autoexported symbols, when the source files were built
with LTO. I'll commit a testcase that showcases this issue after
the revert.
Delay-loaded imports creats a load thunk with a symbol name. Before this
change, the name uses a `__imp_load_` prefix. On the other hand, normal
import uses the `__imp_` prefix for the import address pointer. If an
import symbol named `load_func` is imported normally and another named
`func` is imported using delay-load, this can cause a symbol name
collision.
This patch changes delay-load imports to use `__imp___load_` prefix.
Because it is less likely for normal imports to have a name starting in
`__load_` this should reduce the chance of a name collision.
Reviewed By: mstorsjo
Differential Revision: https://reviews.llvm.org/D134464
Before this, LLD sets OrdinalBase to 0, which deviates from usual
practices. This technically would allow LLD to export a symbol using
ordinal 0, however LLD never use export ordinal 0, which results in
binaries with export tables always having an empty export at ordinal 0.
This change makes LLD set OrdinalBase to 1 and not create the empty
export with ordinal 0, which makes its behaviour more in line with both
the MSVC linker and the GNU linker.
Reviewed By: mstorsjo
Differential Revision: https://reviews.llvm.org/D134140
llvm::sort is beneficial even when we use the iterator-based overload,
since it can optionally shuffle the elements (to detect
non-determinism). However llvm::sort is not usable everywhere, for
example, in compiler-rt.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D130406
Move all variables at file-scope or function-static-scope into a hosting structure (lld::CommonLinkerContext) that lives at lldMain()-scope. Drivers will inherit from this structure and add their own global state, in the same way as for the existing COFFLinkerContext.
See discussion in https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html
Differential Revision: https://reviews.llvm.org/D108850
Original commit description:
[LLD] Remove global state in lld/COFF
This patch removes globals from the lldCOFF library, by moving globals
into a context class (COFFLinkingContext) and passing it around wherever
it's needed.
See https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html for
context about removing globals from LLD.
I also haven't moved the `driver` or `config` variables yet.
Differential Revision: https://reviews.llvm.org/D109634
This reverts commit a2fd05ada9030eab2258fff25e77a05adccae128.
Original commits were b4fa71eed34d967195514fe9b0a5211fca2bc5bc
and e03c7e367adb8f228332e3c2ef8f45484597b719.
check for timer output"
Seems to be causing a number of asan test failures.
This reverts commit b4fa71eed34d967195514fe9b0a5211fca2bc5bc
and e03c7e367adb8f228332e3c2ef8f45484597b719.
This patch removes globals from the lldCOFF library, by moving globals
into a context class (COFFLinkingContext) and passing it around wherever
it's needed.
See https://lists.llvm.org/pipermail/llvm-dev/2021-June/151184.html for
context about removing globals from LLD.
I also haven't moved the `driver` or `config` variables yet.
Differential Revision: https://reviews.llvm.org/D109634
The following class isn't part of the export table; there's a
second correctly placed comment about the things that actually
belong to the export table.
As this isn't handled as a regular relocation, the normal handling of
maybeReportRelocationToDiscarded in Chunks.cpp doesn't apply here.
This would have caught the issue fixed by
82de4e075339f5ad8d68cfe31eb45b771d4750ae.
Differential Revision: https://reviews.llvm.org/D102115
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D87544
This broke both Firefox and Chromium (PR47905) due to what seems like dllimport
function not being handled correctly.
> This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
> Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.
>
> Reviewed By: rnk
>
> Differential Revision: https://reviews.llvm.org/D87544
This reverts commit cfd8481da1adba1952e0f6ecd00440986e49a946.
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D87544
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D87544
The alignment of ARM64 range extension thunks was fixed in
7c816492197a, but ARM range extension thunks, and import
and delay import thunks also need aligning (like all code on ARM
platforms).
I'm adding a test for alignment of ARM64 import thunks - not
specifically adding tests for misalignment of all of them though.
Differential Revision: https://reviews.llvm.org/D77796
E.g. for x86_64, previously each symbol's thunk was 87 bytes. Now
there's a 12 byte thunk per symbol, plus a shared 83 byte tail
function.
This is similar to what both MS link.exe and GNU tools do for
delay imports.
Differential Revision: https://reviews.llvm.org/D64288
llvm-svn: 365823
This patch does the same thing as r365595 to other subdirectories,
which completes the naming style change for the entire lld directory.
With this, the naming style conversion is complete for lld.
Differential Revision: https://reviews.llvm.org/D64473
llvm-svn: 365730
Shaves another pointer off of SectionChunk, reducing the size from 96 to
88 bytes, down from 144 before I started working on this. Combined with
D62356, this reduced peak memory usage when linking chrome_child.dll
from 713MB to 675MB, or 5%.
Create NonSectionChunk to provide virtual dispatch to the rest of the
chunk types.
Reviewers: ruiu, aganea
Differential Revision: https://reviews.llvm.org/D62362
llvm-svn: 361667
The previous patch lost the call to PowerOf2Ceil, which causes LLD to
crash when handling common symbols with a non-power-of-2 size. I tweaked
the existing common.test to make the bsspad16 common symbol be 15 bytes
to add coverage for this case.
llvm-svn: 361426
Summary:
Valid section or chunk alignments are powers of 2 in the range [1,
8192]. These can be stored more canonically in log2 form to free up some
bits in Chunk. Combined with D61696, SectionChunk gets 8 bytes smaller.
Reviewers: ruiu, aganea
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61698
llvm-svn: 361206
Summary:
Prior to this change, every implementation of writeTo would add
OutputSectionOff to the output section buffer start before writing data.
Instead, do this math in the caller, so that it can be written once
instead of many times.
The output section offset is always equivalent to the difference between
the chunk RVA and the output section RVA, so we can replace the one
remaining usage of OutputSectionOff with that subtraction.
This doesn't change the size of SectionChunk because of alignment
requirements, but I will rearrange the fields in a follow-up change to
accomplish that.
Reviewers: ruiu, aganea
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61696
llvm-svn: 360376
Previously, we assumed that .rdata is zero-filled, so when writing
an COFF import table, we didn't write anything if the data is zero.
That assumption was wrong because .rdata can be merged with .text.
If .rdata is merged with .text, they are initialized with 0xcc which
is a trap instruction.
This patch removes that assumption from code.
Should be merged to 8.0 branch as this is a regression.
Fixes https://bugs.llvm.org/show_bug.cgi?id=39826
Differential Revision: https://reviews.llvm.org/D57168
llvm-svn: 352082
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
We initialize .text section with 0xcc (INT3 instruction), so we need to
explicitly write data even if it is zero if it can be in a .text section.
If you specify /merge:.rdata=.text, .rdata (which contains .idata) is put
to .text, so we need to do this.
Fixes https://bugs.llvm.org/show_bug.cgi?id=39826
Differential Revision: https://reviews.llvm.org/D55098
llvm-svn: 348000
GNU binutils import libraries aren't the same kind of short import
libraries as link.exe and LLD produce, but are a plain static library
containing .idata section chunks. MSVC link.exe can successfully link
to them.
In order for imports from GNU import libraries to mix properly with the
normal import chunks, the chunks from the existing mechanism needs to
be added into named sections like .idata$2.
These GNU import libraries consist of one header object, a number of
object files, one for each imported function/variable, and one trailer.
Within the import libraries, the object files are ordered alphabetically
in this order. The chunks stemming from these libraries have to be
grouped by what library they originate from and sorted, to make sure
the section chunks for headers and trailers for the lists are ordered
as intended. This is done on all sections named .idata$*, before adding
the synthesized chunks to them.
Differential Revision: https://reviews.llvm.org/D38513
llvm-svn: 342777
The profailing style in lld seem to be to not include such empty lines.
Clang-tidy/clang-format seem to handle this just fine.
Differential Revision: https://reviews.llvm.org/D43528
llvm-svn: 325629
The same adjustment is already done for the entry point in
Writer.cpp and for relocations that point to executable code
in Chunks.cpp.
Differential Revision: https://reviews.llvm.org/D35767
llvm-svn: 308953
This fixes cases on ARM64 when importing from more than one DLL,
in case the imports from the first DLL ended up unaligned.
When fixing up a IMAGE_REL_ARM64_PAGEOFFSET_12L, which shifts the
offset by the load/store size, check that the shift doesn't discard
any bits. (This would also detect if the import address chunks were
unaligned.)
Differential revision: https://reviews.llvm.org/D35640
llvm-svn: 308585
