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
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.
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
Much of NOLOAD's intended use is to explicitly change the type of an
output section, so we shouldn't flag these as warnings.
Differential Revision: https://reviews.llvm.org/D151144
A code-review comment to change a couple of CHECK to CHECK-NEXT that I
forgot to apply prior to committing.
Differential Revision: https://reviews.llvm.org/D150445
In D72756 the change to add INPUT_SECTION_FLAGS inadvertantly
removed the line to parse the program header assignment information for
OutputSections within an OVERLAY.
This change adds back the missing line and adds a test for it.
Differential Revision: https://reviews.llvm.org/D150445
D73518 mentioned non-STT_SECTION symbol names. This patch extends the code to
handle STT_SECTION symbols, where we report the section name.
This change helps at least the following cases with very little code.
* Whether a out-of-range relocation is due to code or data.
* For a relocation in .debug_info, which referenced `.debug_*` section (due to DWARF32 limitation) causes the problem.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D145199
This is in accordance with avr-gcc, even '-mno-relax' is specified
to avr-gcc, this flag will also be added to the output relocatables.
With this flag set, the GNU ld will perform long call -> short call
optimization for AVR, otherwise not.
Fixes https://github.com/llvm/llvm-project/issues/54508
Reviewed By: MaskRay, jacquesguan, aykevl
Differential Revision: https://reviews.llvm.org/D144617
This prepares for an upcoming change to make --print-imm-hex the default
behavior of llvm-objdump. These tests were updated in a semi-automatic
fashion.
See D136972 for details.
We currently process one OutputSection at a time and for each OutputSection
write contained input sections in parallel. This strategy does not leverage
multi-threading well. Instead, parallelize writes of different OutputSections.
The default TaskSize for parallelFor often leads to inferior sharding. We
prepare the task in the caller instead.
* Move llvm::parallel::detail::TaskGroup to llvm::parallel::TaskGroup
* Add llvm::parallel::TaskGroup::execute.
* Change writeSections to declare TaskGroup and pass it to writeTo.
Speed-up with --threads=8:
* clang -DCMAKE_BUILD_TYPE=Release: 1.11x as fast
* clang -DCMAKE_BUILD_TYPE=Debug: 1.10x as fast
* chrome -DCMAKE_BUILD_TYPE=Release: 1.04x as fast
* scylladb build/release: 1.09x as fast
On M1, many benchmarks are a small fraction of a percentage faster. Mozilla showed the largest difference with the patch being about 1.03x as fast.
Differential Revision: https://reviews.llvm.org/D131247
For 1 != 1 <= 1 ? 1 : 2, the current code incorrectly considers that ?
has a higher precedence than != (minPrec).
Also, add a test for right associativity.
GNU ld does not allow `.foo : { (*foo) }`, but we may recognize it as three
input section descriptions: file "(" with any section name, file "*foo" with
any section name, file ")" with any section name. Disallow the error-prone usage.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D125523
Placing a non-SHT_NOBITS input section in an output section specified with
(NOLOAD) is fishy but used by some projects. D118840 changed the output type to
SHT_PROGBITS, but using the specified type seems to make more sense and improve
GNU ld compatibility: `(NOLOAD)` seems to change the output section type
regardless of input.
I think we should keep the current type mismatch warning as it does indicate an
error-prone usage.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D125074
We currently hard code RELRO sections. When a custom section is between
DATA_SEGMENT_ALIGN and DATA_SEGMENT_RELRO_END, we may report a spurious
`error: section: ... is not contiguous with other relro sections`. GNU ld
makes such sections RELRO.
glibc recently switched to default --with-default-link=no. This configuration
places `__libc_atexit` and others between DATA_SEGMENT_ALIGN and
DATA_SEGMENT_RELRO_END. This patch allows such a ld.bfd --verbose
linker script to be fed into lld.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D124656
Linux kernel arch/arm64/kernel/vmlinux.lds.S discards .dynsym . D123985 triggers
a spurious assertion failure. Detect the case with
`!mainPart->dynSymTab->getParent()`.
Making a (NOLOAD) section SHT_PROGBITS is fishy (the user may expect all-zero
content, but the linker does not check that), but some projects (e.g. Linux
kernel https://github.com/ClangBuiltLinux/linux/issues/1597) traditionally rely
on the behavior. Issue a warning to not break them.
The current output section type allows to set the ELF section type to
SHT_PROGBITS or SHT_NOLOAD. This patch allows an arbitrary section value
to be specified. Some common SHT_* literal names are supported as well.
```
SECTIONS {
note (TYPE=SHT_NOTE) : { BYTE(8) *(note) }
init_array ( TYPE=14 ) : { QUAD(14) }
fini_array (TYPE = SHT_FINI_ARRAY) : { QUAD(15) }
}
```
When `sh_type` is specified, it is an error if an input section has a different type.
Our syntax is compatible with GNU ld 2.39 (https://sourceware.org/bugzilla/show_bug.cgi?id=28841).
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D118840
See the updated insert-before.test for the effects: many synthetic
sections are SHF_ALLOC|SHF_WRITE. If they are discarded, we don't want
to propagate their flags to subsequent output section descriptions.
`getFirstInputSection(sec) == nullptr` can technically be merged into
`isDiscardable` but I'd like to postpone that as not sharing code may give more
refactoring opportunity.
Depends on D118529.
Reviewed By: peter.smith, bluca
Differential Revision: https://reviews.llvm.org/D118530
adjustSectionsBeforeSorting updates some output section attributes
(alignment/flags) and removes discardable empty sections. When it is called,
INSERT commands have not been processed. Therefore the flags propagation rule
may not affect output sections defined in an INSERT command properly.
Fix this by moving processInsertCommands before adjustSectionsBeforeSorting.
adjustSectionsBeforeSorting is somewhat misnamed. The order between it and
sortInputSections does not matter. With the pass shuffle, the name of
adjustSectionsBeforeSorting becomes wrong. Therefore rename it. The new
name is not set into stone. The function mixes several tasks and the
code may be refactored in a way that we may give them more meaningful
names.
With this patch, I think the behavior of attribute propagation becomes more
reasonable. In particular, in the absence of non-INSERT SECTIONS,
inserting a section after a SHF_ALLOC one will give us a SHF_ALLOC section,
not a non-SHF_ALLOC one (see linkerscript/insert-after.test).
Reviewed By: peter.smith, bluca
Differential Revision: https://reviews.llvm.org/D118529
db08df0570 does not work because part.relrDyn is
a unique_ptr and `reset` destroys the object which may still be referenced.
This commit uses the D114180 approach. Also improve the test to check that there
is no R_X86_64_RELATIVE.
