We want lld-link to automatically find compiler-rt's and
libc++ when it's in the same directory as the rest of the
toolchain. This is because on Windows linking isn't done
via the clang driver - but instead invoked directly.
This prepends: <llvm>/lib <llvm>/lib/clang/XX/lib and
<llvm>/lib/clang/XX/lib/windows automatically to the library
search paths.
Related to #63827
Differential Revision: https://reviews.llvm.org/D151188
This patch is spun out of https://reviews.llvm.org/D151188
and makes it possible for lld-link to find libraries with
relative paths. This will be used later to implement the
changes to autolinking runtimes explained in #63827
Differential Revision: https://reviews.llvm.org/D155268
While working on adding more implicit search paths to the
lld COFF driver, it was helpful to have a way to print all
the search paths, both for debugging and for testing without
having to create very complicated test cases.
This is a simple arg that just prints the search paths and exits.
Related to the efforts in #63827
Differential Revision: https://reviews.llvm.org/D155047
Annotation attributes may be attached to a function to mark it with
custom data that will be contained in the final Wasm file. The
annotation causes a custom section named
"func_attr.annotate.<name>.<arg0>.<arg1>..." to be created that will
contain each function's index value that was marked with the annotation.
A new patchable relocation type for function indexes had to be created so
the custom section could be updated during linking.
Reviewed By: sbc100
Differential Revision: https://reviews.llvm.org/D150803
In 64 bit mode, any references to symbols that might end up autoimported
must be made via full 64 bit pointers (usually in .refptr stubs
generated by the compiler).
If referenced via e.g. a 32 bit rip relative offset, it might work
as long as DLLs are loaded close together in the 64 bit address
space, but will fail surprisingly later if they happen to be loaded
further apart. Any cases of that happening is usually a toolchain
error, and the sooner we can warn about it, the easier it is to diagnose.
Differential Revision: https://reviews.llvm.org/D154777
Previously, the same file could be used across diagnostic options but
the file would be silently overwritten by the whichever option gets
handled last.
Differential Revision: https://reviews.llvm.org/D153873
Consider a setup without a system-wide installation of lit.
Instead you pass the path to lit like this:
```
cmake ...
-DLLVM_EXTERNAL_LIT=<PATH_TO_LIT_BINARY> ...
```
Then you will run into this error:
```
ninja: error: unknown target 'check-lld'
```
I have a buildbot builder that fails with this message. Here's the
passage that triggers this error:
d3bfd5ccbc/zorg/buildbot/builders/annotated/standalone-build.sh (L194-L239)
By using `LLVM_EXTERNAL_LIT` instead of `LLVM_LIT` we fix this problem.
See
[here](https://llvm.org/docs/GettingStarted.html#stand-alone-builds) for
a description:
> Both the LLVM_ROOT and LLVM_EXTERNAL_LIT options are required to do stand-alone builds for all sub-projects. Additional required options for each sub-project can be found in the table below.
Differential Revision: https://reviews.llvm.org/D154599
This commit provides linker support for Cortex-M Security Extensions (CMSE).
The specification for this feature can be found in ARM v8-M Security Extensions:
Requirements on Development Tools.
The linker synthesizes a security gateway veneer in a special section;
`.gnu.sgstubs`, when it finds non-local symbols `__acle_se_<entry>` and `<entry>`,
defined relative to the same text section and having the same address. The
address of `<entry>` is retargeted to the starting address of the
linker-synthesized security gateway veneer in section `.gnu.sgstubs`.
In summary, the linker translates input:
```
.text
entry:
__acle_se_entry:
[entry_code]
```
into:
```
.section .gnu.sgstubs
entry:
SG
B.W __acle_se_entry
.text
__acle_se_entry:
[entry_code]
```
If addresses of `__acle_se_<entry>` and `<entry>` are not equal, the linker
considers that `<entry>` already defines a secure gateway veneer so does not
synthesize one.
If `--out-implib=<out.lib>` is specified, the linker writes the list of secure
gateway veneers into a CMSE import library `<out.lib>`. The CMSE import library
will have 3 sections: `.symtab`, `.strtab`, `.shstrtab`. For every secure gateway
veneer <entry> at address `<addr>`, `.symtab` contains a `SHN_ABS` symbol `<entry>` with
value `<addr>`.
If `--in-implib=<in.lib>` is specified, the linker reads the existing CMSE import
library `<in.lib>` and preserves the entry function addresses in the resulting
executable and new import library.
Reviewed By: MaskRay, peter.smith
Differential Revision: https://reviews.llvm.org/D139092
Section names used in ELF linker scripts can be quoted, but such
quotes must not be propagated to the binary ELF section names. As
such strip the quotes from the section names when processing them, and
also strip them from linker script functions that take section names
as parameters.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D124266
This patch added /dwodir to lld/COFF which is equivalent to lld/ELF
option -plugin-opt=dwo_dir=. This option tells LTO backend to create
dwo directory and files and all dwo files will be in it. Otherwise all
dwarf sections will be embeded into image even if -gsplit-dwarf is
specified when using LTO.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D154070
This patch adds a thunk for Thumb long branch on V6-M for eXecute Only.
Note that there is currently no support for a position independant and
eXecute Only V6-M long branch thunk
Differential Revision: https://reviews.llvm.org/D153772
With relative vtables the caller jumps directly to the plt entries in the shared object,
therefore landing pad is need for these entries.
Reproducer:
main.cpp
```
#include "v.hpp"
int main() {
A* a = new B();
a->do_something2();
return 0;
}
```
v.hpp
```
struct A {
virtual void do_something() = 0;
virtual void do_something2();
};
struct B : public A {
void do_something() override;
void do_something2() override;
};
```
v.cpp
```
#include "v.hpp"
void A::do_something2() { }
void B::do_something() { }
void B::do_something2() { }
```
```
CC="clang++ --target=aarch64-unknown-linux-gnu -fuse-ld=lld -mbranch-protection=bti"
F=-fexperimental-relative-c++-abi-vtables
${=CC} $F -shared v.cpp -o v.so -z force-bti
${=CC} $F main.cpp -L./ v.so -Wl,-rpath=. -z force-bti
qemu-aarch64-static -L /usr/aarch64-linux-gnu -cpu max ./a.out
```
For v.so, the regular vtable entry is relocated by an R_AARCH64_ABS64 relocation referencing _ZN1B13do_something2Ev.
```
_ZTV1B:
.xword _ZN1B13do_something2Ev
```
Using relative vtable entry for a DSO has a downside of creating many PLT entries and making their addresses escape.
The relative vtable entry references a PLT entry _ZN1B13do_something2Ev@plt.
```
.L_ZTV1A.local:
.word (_ZN1A13do_something2Ev@PLT-.L_ZTV1A.local)-8
```
fixes: #63580
Reviewed By: peter.smith, MaskRay
Differential Revision: https://reviews.llvm.org/D153264
An .ARM.attributes section is divided into subsections, each labelled
with a vendor name. There is one standardised vendor name, which must
be used for all attributes that affect compatibility. Subsections
labelled with other vendor names can be used for optimisation
purposes, but it has to be safe for an object file consumer to ignore
them if it doesn't recognise the vendor name.
LLD currently terminates parsing of the whole attributes section as
soon as it encounters a subsection with a vendor name it doesn't
recognise (which is anything other than the standard one). This can
prevent it from detecting compatibility issues, if a standard
subsection followed the vendor-specific one.
This patch modifies the attribute parser so that unrecognised vendor
subsections are silently skipped, and the subsections beyond them are
still processed.
(Relanded with no change from the original commit 8f208edd44. I
reverted it in 949bb7e4de due to widespread buildbot breakage,
failing to notice that 975f71faa7 had already fixed the failing
unit test. Also, the *revert* caused at least one buildbot to fail,
because I switched the affected lld test to making %t a directory, and
then the reverted version tried to treat it as a file without cleaning
the output directory first.)
Differential Revision: https://reviews.llvm.org/D153335
This reverts commit 8f208edd44.
I completely missed the compiled unit test for ELFAttributeParser,
which also needs updating. I'll reland this change once I make further
fixes.
An .ARM.attributes section is divided into subsections, each labelled
with a vendor name. There is one standardised vendor name, which must
be used for all attributes that affect compatibility. Subsections
labelled with other vendor names can be used for optimisation
purposes, but it has to be safe for an object file consumer to ignore
them if it doesn't recognise the vendor name.
LLD currently terminates parsing of the whole attributes section as
soon as it encounters a subsection with a vendor name it doesn't
recognise (which is anything other than the standard one). This can
prevent it from detecting compatibility issues, if a standard
subsection followed the vendor-specific one.
This patch modifies the attribute parser so that unrecognised vendor
subsections are silently skipped, and the subsections beyond them are
still processed.
Differential Revision: https://reviews.llvm.org/D153335
In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.
This reverts commit c4fea39056.
I am reverting this for now until I figure out how to fix
the build bot errors and warnings.
Errors:
llvm-project/lld/ELF/Arch/ARM.cpp:1300:29: error: expected primary-expression before ‘>’ token
osec->writeHeaderTo<ELFT>(++sHdrs);
Warnings:
llvm-project/lld/ELF/Arch/ARM.cpp:1306:31: warning: left operand of comma operator has no effect [-Wunused-value]
This commit provides linker support for Cortex-M Security Extensions (CMSE).
The specification for this feature can be found in ARM v8-M Security Extensions:
Requirements on Development Tools.
The linker synthesizes a security gateway veneer in a special section;
`.gnu.sgstubs`, when it finds non-local symbols `__acle_se_<entry>` and `<entry>`,
defined relative to the same text section and having the same address. The
address of `<entry>` is retargeted to the starting address of the
linker-synthesized security gateway veneer in section `.gnu.sgstubs`.
In summary, the linker translates input:
```
.text
entry:
__acle_se_entry:
[entry_code]
```
into:
```
.section .gnu.sgstubs
entry:
SG
B.W __acle_se_entry
.text
__acle_se_entry:
[entry_code]
```
If addresses of `__acle_se_<entry>` and `<entry>` are not equal, the linker
considers that `<entry>` already defines a secure gateway veneer so does not
synthesize one.
If `--out-implib=<out.lib>` is specified, the linker writes the list of secure
gateway veneers into a CMSE import library `<out.lib>`. The CMSE import library
will have 3 sections: `.symtab`, `.strtab`, `.shstrtab`. For every secure gateway
veneer <entry> at address `<addr>`, `.symtab` contains a `SHN_ABS` symbol `<entry>` with
value `<addr>`.
If `--in-implib=<in.lib>` is specified, the linker reads the existing CMSE import
library `<in.lib>` and preserves the entry function addresses in the resulting
executable and new import library.
Reviewed By: MaskRay, peter.smith
Differential Revision: https://reviews.llvm.org/D139092
The test requires that LLVM integreated assembler generates
SUBTRACTOR/UNSIGNED relocations for `.long _minuend_1 - _subtrahend_1`.
This currently works by luck because:
* `_minuend_1` and `_subtrahend_1` are in different fragments (separated by a MCFillFragment)
* and the result is known to be negative at parsing time.
D153096 will change the assembler to fold `.long _minuend_1 - _subtrahend_1` to
a constant, giving ld -order_file no chance to change the result.
To fix the test, move the referenced labels after the label differences to block
constant folding.
Note: you may think the model is somewhat broken and it is. The
.subsections_via_symbols mechanism does not block such constant folding. In
reality SUBTRACTOR/UNSIGNED is for references to another section, which does not
have the problem.
Reviewed By: #lld-macho, smeenai
Differential Revision: https://reviews.llvm.org/D153382
2700da5fe2 added lld/test/Unit/lit.site.cfg.py.in in a state
that half-supports relocatable lld lit tests.
Make them fully relocatable.
See description of fb80b6b2d5 for background.
Differential Revision: https://reviews.llvm.org/D152885
Arm has BE8 big endian configuration called a byte-invariant(every byte has the same address on little and big-endian systems).
When in BE8 mode:
1. Instructions are big-endian in relocatable objects but
little-endian in executables and shared objects.
2. Data is big-endian.
3. The data encoding of the ELF file is ELFDATA2MSB.
To support BE8 without an ABI break for relocatable objects,the linker takes on the responsibility of changing the endianness of instructions. At a high level the only difference between BE32 and BE8 in the linker is that for BE8:
1. The linker sets the flag EF_ARM_BE8 in the ELF header.
2. The linker endian reverses the instructions, but not data.
This patch adds BE8 big endian support for Arm. To endian reverse the instructions we'll need access to the mapping symbols. Code sections can contain a mix of Arm, Thumb and literal data. We need to endian reverse Arm instructions as words, Thumb instructions
as half-words and ignore literal data.The only way to find these transitions precisely is by using mapping symbols. The instruction reversal will need to take place after relocation. For Arm BE8 code sections (Section has SHF_EXECINSTR flag ) we inserted a step after relocation to endian reverse the instructions. The implementation strategy i have used here is to write all sections BE32 including SyntheticSections then endian reverse all code in InputSections via mapping symbols.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D150870
The left/right shift linker script operators may trigger UB.
E.g. in linkerscript/end-overflow-check.test, the initial REGION1__PADDED_SR_SHIFT is
uint64_t(-3), cause the following expression to trigger an out-of-range shift in
a ubsan build of lld.
REGION1__PADDED_SR_SIZE = MAX(1 << REGION1__PADDED_SR_SHIFT, 32);
Protect such UBs by making RHS less than 64.
As of Xcode 15 there is now a tool ID for LLD, likely driven by Apple's
tests with using LLD for their CAS work in clang. This updates LLD to
use the correct ID, and updates the object library so that llvm-objdump
prints it correctly.
Differential Revision: https://reviews.llvm.org/D152929
LLD terminates with errors when it detects overflows in the
finalizeAddressDependentContent calculation. Although, sometimes, those errors
are not really errors, but an intermediate result of an ongoing address
calculation. If we continue the fixed-point algorithm we can converge to the
correct result.
This patch
* Removes the verification inside the fixed point algorithm.
* Calls checkMemoryRegions at the end.
Reviewed By: peter.smith, MaskRay
Differential Revision: https://reviews.llvm.org/D152170
The warning "ignoring memory region assignment for non-allocatable section" should be generated under the following conditions:
* sections without SHF_ALLOC attribute and,
* presence of input sections or data commands (ByteCommand)
The goal of the change is to reduce spurious warnings that are generated for some output sections that have no input section.
Reviewed By: MaskRay, peter.smith
Differential Revision: https://reviews.llvm.org/D151802
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
Reasons for rolling forward:
- the crash reported from Chromium was fixed in D151824 (not related to this patch at all)
- since D152824 was committed, it should now be safe to roll this forward.
New change:
- add an additional _ in name check
This reverts commit 4980eead4d.
This reverts commit 11d61c079d to re-apply
6836a47b7e with modifications.
Specifically, the errors in DWARFAbbreviationDeclaration::extract needed
to be moved as they are returned to ensure the right Error constructor
is selected.
Follow up to D151815.
Or else we properly handle the first instance of a file, then error out on the second instance of the same file.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D152198
In trying to hoist errors further up this callstack, I discovered that
if the data in the debug_abbrev section is invalid entirely, the code
that parses the debug_abbrev section may do strange or unpredictable
things. The underlying issue is that DataExtractor will return a value
of 0 when it encounters an error in extracting a LEB128 value. It's thus
difficult to determine if there was an error just by looking at the
return value. This patch aims to bail at the first sight of an error in
the debug_abbrev parsing code.
Differential Revision: https://reviews.llvm.org/D151755
As suggested by @erichkeane in
https://reviews.llvm.org/D141451#inline-1429549
There's potential for a lot more cleanups around these APIs. This is
just a start.
Callers need to be more careful about sub-expressions producing strings
that don't outlast the expression using `llvm::demangle`. Add a
release note.
Differential Revision: https://reviews.llvm.org/D149104
