For -fno-pic, without DW_EH_PE_indirect, the personality routine pointer in a
CIE needs an R_AARCH64_ABS64 relocation. In common configurations that
`__gcc_personality_v0` is defined in a shared object, this will lead to a
discouraged canonical PLT entry, or, if `ld.lld -z notext` (betwen D122459 and
D143136), a dynamic R_AARCH64_ABS64 relocation with an incorrect offset:
https://github.com/llvm/llvm-project/issues/60392
Since GCC uses DW_EH_PE_indirect for -fno-pic code (the behavior hasn't changed
since the initial port in 2012), let's follow suit by simplifying the code.
(
For tiny and small code models, we use DW_EH_PE_sdata8 instead of GCC's
DW_EH_PE_sdata4. This is a deliberate choice to support personality-.eh_frame
offset > 2GiB. This is necessary for small code model since "Max text segment
size < 2GiB" but it is unnecessary to make `-fno-pic -mcmodel={tiny,small}`
different: The scenarios that uses both -fno-pic and C++ exceptions have been
increasingly rare now, so there is little advantage optimizing for the little
size saving with code complexity.
)
Reviewed By: MatzeB
Differential Revision: https://reviews.llvm.org/D143039
Summary: The toc-data feature has been supported for assembly file generation.
This patch handles the toc-data for object file generation.
Reviewed By: shchenz
Differential Revision: https://reviews.llvm.org/D139516
With https://reviews.llvm.org/D136627, now we have the metrics for profile staleness based on profile statistics, monitoring the profile staleness in real-time can help user quickly identify performance issues. For a production scenario, the build is usually incremental and if we want the real-time metrics, we should store/cache all the old object's metrics somewhere and pull them in a post-build time. To make it more convenient, this patch add an option to persist them into the object binary, the metrics can be reported right away by decoding the binary rather than polling the previous stdout/stderrs from a cache system.
For implementation, it writes the statistics first into a new metadata section(llvm.stats) then encode into a special ELF `.llvm_stats` section. The section data is formatted as a list of key/value pair so that future statistics can be easily extended. This is also under a new switch(`-persist-profile-staleness`)
In terms of size overhead, the metrics are computed at module level, so the size overhead should be small, measured on one of our internal service, it costs less than < 1MB for a 10GB+ binary.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D136698
Currently we treat initializers with init_seg(compiler/lib) as similar
to any other init_seg, they simply have a global variable in the proper
section (".CRT$XCC" for compiler/".CRT$XCL" for lib) and are added to
llvm.used. However, this doesn't match with how LLVM sees normal (or
init_seg(user)) initializers via llvm.global_ctors. This
causes issues like incorrect init_seg(compiler) vs init_seg(user)
ordering due to GlobalOpt evaluating constructors, and the
ability to remove init_seg(compiler/lib) initializers at all.
Currently we use 'A' for priorities less than 200. Use 200 for
init_seg(compiler) (".CRT$XCC") and 400 for init_seg(lib) (".CRT$XCL"),
which do not append the priority to the section name. Priorities
between 200 and 400 use ".CRT$XCC${Priority}". This allows for
some wiggle room for people/future extensions that want to add
initializers between compiler and lib.
Fixes#56922
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D131910
TLS debug on AIX is not ready for now.
The location generated in no-integrated-as mode is wrong and
in integrated-as mode causes AIX linker error.
Reviewed By: Esme
Differential Revision: https://reviews.llvm.org/D130245
This patchs adds a new metadata kind `exclude` which implies that the
global variable should be given the necessary flags during code
generation to not be included in the final executable. This is done
using the ``SHF_EXCLUDE`` flag on ELF for example. This should make it
easier to specify this flag on a variable without needing to explicitly
check the section name in the target backend.
Depends on D129053 D129052
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D129151
Currently we use the `.llvm.offloading` section to store device-side
objects inside the host, creating a fat binary. The contents of these
sections is currently determined by the name of the section while it
should ideally be determined by its type. This patch adds the new
`SHT_LLVM_OFFLOADING` section type to the ELF section types. Which
should make it easier to identify this specific data format.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D129052
Summary:
We use the special section name `.llvm.offloading` to store device
imagees in the host object file. We want these to be stripped by the
linker as they are not used after linking so we use the `SHF_EXCLUDE`
flag to instruct the linker to drop them. We used to do this for all
sections that started with `.llvm.offloading` when we encoded metadata
in the section name itself. Now we embed a special binary containing the
metadata, we should only add the flag on this name specifically.
Summary:
When -ffunction-sections is on, this patch makes the compiler to generate unique LSDA and EH info sections for functions on AIX by appending the function name to the section name as a suffix. This will allow the AIX linker to garbage-collect unused function.
Reviewed by: MaskRay, hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D124855
Offloading sections can be embedded in the host during codegen via a
section. This section was originally marked as metadata to prevent it
from being loaded, but these sections are completely unused at runtime
so the linker should automatically drop them from the final executable
or shard library. This flag adds support for the SHF_EXCLUDE flag in
target lowering and uses it.
Reviewed By: JonChesterfield, MaskRay
Differential Revision: https://reviews.llvm.org/D122987
For MachO, lower `@llvm.global_dtors` into `@llvm_global_ctors` with
`__cxa_atexit` calls to avoid emitting the deprecated `__mod_term_func`.
Reuse the existing `WebAssemblyLowerGlobalDtors.cpp` to accomplish this.
Enable fallback to the old behavior via Clang driver flag
(`-fregister-global-dtors-with-atexit`) or llc / code generation flag
(`-lower-global-dtors-via-cxa-atexit`). This escape hatch will be
removed in the future.
Differential Revision: https://reviews.llvm.org/D121736
For MachO, lower `@llvm.global_dtors` into `@llvm_global_ctors` with
`__cxa_atexit` calls to avoid emitting the deprecated `__mod_term_func`.
Reuse the existing `WebAssemblyLowerGlobalDtors.cpp` to accomplish this.
Enable fallback to the old behavior via Clang driver flag
(`-fregister-global-dtors-with-atexit`) or llc / code generation flag
(`-lower-global-dtors-via-cxa-atexit`). This escape hatch will be
removed in the future.
Differential Revision: https://reviews.llvm.org/D121736
For MachO, lower `@llvm.global_dtors` into `@llvm_global_ctors` with
`__cxa_atexit` calls to avoid emitting the deprecated `__mod_term_func`.
Reuse the existing `WebAssemblyLowerGlobalDtors.cpp` to accomplish this.
Enable fallback to the old behavior via Clang driver flag
(`-fregister-global-dtors-with-atexit`) or llc / code generation flag
(`-lower-global-dtors-via-cxa-atexit`). This escape hatch will be
removed in the future.
Differential Revision: https://reviews.llvm.org/D121327
As requested in D107955 <https://reviews.llvm.org/D107955>, this patch
splits off the `MC` and `CodeGen` parts and adds a testcase.
Tested on `sparcv9-sun-solaris2.11`, `amd64-pc-solaris2.11`, and
`x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D120318
We use offloading sections in the new Clang driver scheme to embed
device code into the host. We later use these sections to link the
device image, after which point they are completely unused and should
not be loaded into memory if they are still in the executable.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D120275
This ports the `.cg_profile` assembly directive and call graph profile section
generation to MachO from COFF/ELF. Due to MachO section naming rules, the
section is called `__LLVM,__cg_profile` rather than `.llvm.call-graph-profile`
as in COFF/ELF. Support for llvm-readobj is included to facilitate testing.
Corresponding LLD change is D112164
Differential Revision: https://reviews.llvm.org/D112160
Currently, the code in TargetLoweringObjectFile only assigns
@init_array section type to plain .init_array sections, but not
prioritized sections like .init_array.00001.
This is inconsistent with the interpretation in the AsmParser
(see 791523bae6/llvm/lib/MC/MCParser/ELFAsmParser.cpp (L621-L632))
and upcoming expectations in LLD
(see https://github.com/rust-lang/rust/issues/92181 for context).
This patch assigns @init_array section type to all sections with an
.init_array prefix. The same is done for .fini_array and
.preinit_array as well. With that, the logic matches the AsmParser.
Differential Revision: https://reviews.llvm.org/D116528
This reverts commit fd4808887ee47f3ec8a030e9211169ef4fb094c3.
This patch causes gcc to issue a lot of warnings like:
warning: base class ‘class llvm::MCParsedAsmOperand’ should be
explicitly initialized in the copy constructor [-Wextra]
To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunction
(D109792), the function is renamed to getAliaseeObject.
This renames the primary methods for creating a zero value to `getZero`
instead of `getNullValue` and renames predicates like `isAllOnesValue`
to simply `isAllOnes`. This achieves two things:
1) This starts standardizing predicates across the LLVM codebase,
following (in this case) ConstantInt. The word "Value" doesn't
convey anything of merit, and is missing in some of the other things.
2) Calling an integer "null" doesn't make any sense. The original sin
here is mine and I've regretted it for years. This moves us to calling
it "zero" instead, which is correct!
APInt is widely used and I don't think anyone is keen to take massive source
breakage on anything so core, at least not all in one go. As such, this
doesn't actually delete any entrypoints, it "soft deprecates" them with a
comment.
Included in this patch are changes to a bunch of the codebase, but there are
more. We should normalize SelectionDAG and other APIs as well, which would
make the API change more mechanical.
Differential Revision: https://reviews.llvm.org/D109483
The introduction of `SHF_GNU_RETAIN` has caused massive problems on Solaris.
Initially, as reported in Bug 49437, it caused dozens of testsuite failures
on both sparc and x86. The objects were marked as `ELFOSABI_NONE`, but
`SHF_GNU_RETAIN` is a GNU extension. In the native Solaris ABI, that flag
(in the range for OS-specific values) is `SHF_SUNW_ABSENT` with a
completely different semantics, which confuses Solaris `ld` very much.
Later, the objects became (correctly) marked `ELFOSABI_GNU`, which Solaris
`ld` doesn't support, causing it to SEGV and break the build. The linker
is currently being hardened to not accept non-native OS ABIs to avoid this.
The need for linker support is already documented in
`clang/include/clang/Basic/AttrDocs.td`, but not currently checked.
This patch avoids all this by not emitting `SHF_GNU_RETAIN` on Solaris at all.
Tested on `amd64-pc-solaris2.11`, `sparcv9-sun-solaris2.11`, and
`x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D107747
We may call lowerRelativeReference in MC to determine whether target
supports this lowering. We should return nullptr instead of crashing
when we haven't implemented the real lowering.
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D107830
Fixes issue where late materialized constants can be more strictly
aligned then their containing csect.
Differential Revision: https://reviews.llvm.org/D103103
- This patch consists of the bare basic code needed in order to generate some assembly for the z/OS target.
- Only the .text and the .bss sections are added for now.
- The relevant MCSectionGOFF/Symbol interfaces have been added. This enables us to print out the GOFF machine code sections.
- This patch enables us to add simple lit tests wherever possible, and contribute to the testing coverage for the z/OS target
- Further improvements and additions will be made in future patches.
Reviewed By: tmatheson
Differential Revision: https://reviews.llvm.org/D106380
In the textual format, `noduplicates` means no COMDAT/section group
deduplication is performed. Therefore, if both sets of sections are retained, and
they happen to define strong external symbols with the same names,
there will be a duplicate definition linker error.
In PE/COFF, the selection kind lowers to `IMAGE_COMDAT_SELECT_NODUPLICATES`.
The name describes the corollary instead of the immediate semantics. The name
can cause confusion to other binary formats (ELF, wasm) which have implemented/
want to implement the "no deduplication" selection kind. Rename it to be clearer.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D106319
The linker can sometimes drop the do_not_dead_strip if it can't associate the
atom with a symbol (the other place to specify no dead-stripping in MachO
files).
<string> is currently the highest impact header in a clang+llvm build:
https://commondatastorage.googleapis.com/chromium-browser-clang/llvm-include-analysis.html
One of the most common places this is being included is the APInt.h header, which needs it for an old toString() implementation that returns std::string - an inefficient method compared to the SmallString versions that it actually wraps.
This patch replaces these APInt/APSInt methods with a pair of llvm::toString() helpers inside StringExtras.h, adjusts users accordingly and removes the <string> from APInt.h - I was hoping that more of these users could be converted to use the SmallString methods, but it appears that most end up creating a std::string anyhow. I avoided trying to use the raw_ostream << operators as well as I didn't want to lose having the integer radix explicit in the code.
Differential Revision: https://reviews.llvm.org/D103888
We will need to set the ssp canary bit in traceback table to communicate
with unwinder about the canary.
Reviewed By: #powerpc, shchenz
Differential Revision: https://reviews.llvm.org/D103202
Precursor to D100944. The logic for determining the unique ID had become
quite difficult to reason about, so I have factored this out into a
separate function.
Differential Revision: https://reviews.llvm.org/D102336
This change was originally landed in: 5000a1b4b9edeb9e994f2a5b36da8d48599bea49
It was reverted in: 061e071d8c9b98526f35cad55a918a4f1615afd4
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
This reverts commit 5000a1b4b9edeb9e994f2a5b36da8d48599bea49.
Breaks tests, see https://reviews.llvm.org/D97657#2749151
Easily repros locally with `ninja check-llvm-mc-webassembly`.
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
The logic for x86_64 position-independent TType encodings was backwards,
using 8 bytes where 4 were wanted and 4 where 8 were wanted. For regular
x86_64, this was mostly harmless, exception tables are allowed to use
8-byte encodings even when it is not needed. For the large code model,
and for X32, however, the generated exception tables were wrong. For the
large code model, we cannot assume that the address will fit in 4 bytes.
For X32, we cannot use 64-bit relocations.
Fixes PR50148.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D102132
This untangles the MCContext and the MCObjectFileInfo. There is a circular
dependency between MCContext and MCObjectFileInfo. Currently this dependency
also exists during construction: You can't contruct a MOFI without a MCContext
without constructing the MCContext with a dummy version of that MOFI first.
This removes this dependency during construction. In a perfect world,
MCObjectFileInfo wouldn't depend on MCContext at all, but only be stored in the
MCContext, like other MC information. This is future work.
This also shifts/adds more information to the MCContext making it more
available to the different targets. Namely:
- TargetTriple
- ObjectFileType
- SubtargetInfo
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D101462
Summary:
This patch implements the backend implementation of adding global variables
directly to the table of contents (TOC), rather than adding the address of the
variable to the TOC.
Currently, this patch will look for the "toc-data" attribute on symbols in the
IR, and then add those symbols to the TOC.
ATM, this is implemented for 32 bit AIX.
Reviewers: sfertile
Differential Revision: https://reviews.llvm.org/D101178
