This reverts commit 4bf8a688956a759b7b6b8d94f42d25c13c7af130.
This commit seems to be breaking the semantics of the
ObjectFile::isSectionText method, which breaks numba/llvmlite bindings.
So that when mixing small and large text, large text stays out of the
way of the rest of the binary.
This is useful for mixing precompiled small code model object files and
built-from-source large code model binaries so that the the text
sections don't get merged.
The reland fixes an issue where a function in the large code model would reference small data without GOTOFF.
So that when mixing small and large text, large text stays out of the
way of the rest of the binary.
This is useful for mixing precompiled small code model object files and
built-from-source large code model binaries so that the the text
sections don't get merged.
This PR makes `-basic-block-sections` handle functions with custom
non-dot-text sections correctly. Cold parts of such functions must be
placed in the same section (not in `.text.split`) but with a unique id.
Currently clang's medium code model treats all data as large, putting them in a large data section and using more expensive instruction sequences to access them.
Following gcc's -mlarge-data-threshold, which allows putting data under a certain size in a normal data section as opposed to a large data section. This allows using cheaper code sequences to access some portion of data in the binary (which will be implemented in LLVM in a future patch).
And under the medium codel mode, only put data above the large data threshold into large data sections, not all data.
Reviewed By: MaskRay, rnk
Differential Revision: https://reviews.llvm.org/D149288
The current implementation generates a csect with a
".rodata.str.x.y" prefix for a MergeableCString variable definition.
However, a reference to such variable does not get the prefix in its
name because there's not enough information in the containing IR.
In particular, without seeing the initializer and absent of some other
indicators, we cannot tell that the referenced variable is a null-
terminated string.
When the AIX codegen in llvm was being developed, the prefixing was copied
from ELF without having the linker take advantage of the info.
Currently, the AIX linker does not have the capability to merge
MergeableCString variables. If such feature would ever get implemented,
the contract between the linker and compiler would have to be reconsidered.
Here's the before and after of this change:
```
@a = global i64 320255973571806, align 8
@strA = unnamed_addr constant [7 x i8] c"hello\0A\00", align 1 ;; Mergeable1ByteCString
@strB = unnamed_addr constant [8 x i8] c"Blahah\0A\00", align 1 ;; Mergeable1ByteCString
@strC = unnamed_addr constant [2 x i16] [i16 1, i16 0], align 2 ;; Mergeable2ByteCString
@strD = unnamed_addr constant [2 x i16] [i16 1, i16 1], align 2 ;; !isMergeableCString
@strE = external unnamed_addr constant [2 x i16], align 2
-fdata-sections:
.text extern .rodata.str1.1strA .text extern strA
0 SD RO 0 SD RO
.text extern .rodata.str1.1strB .text extern strB
0 SD RO 0 SD RO
.text extern .rodata.str2.2strC ===> .text extern strC
0 SD RO 0 SD RO
.text extern strD .text extern strD
0 SD RO 0 SD RO
.data extern a .data extern a
0 SD RW 0 SD RW
undef extern strE undef extern strE
0 ER UA 0 ER UA
-fno-data-sections:
.text unamex .rodata.str1.1 .text unamex .rodata
0 SD RO 0 SD RO
.text extern strA .text extern strA
0 LD RO 0 LD RO
.text extern strB .text extern strB
0 LD RO 0 LD RO
.text unamex .rodata.str2.2 ===> .text extern strC
0 SD RO 0 LD RO
.text extern strC .text extern strD
0 LD RO 0 LD RO
.text unamex .rodata .data unamex .data
0 SD RO 0 SD RW
.text extern strD .data extern a
0 LD RO 0 LD RW
.data unamex .data undef extern strE
0 SD RW 0 ER UA
.data extern a
0 LD RW
undef extern strE
0 ER UA
```
Reviewed by: David Tenty, Fangrui Song
Differential Revision: https://reviews.llvm.org/D156202
Summary: D80642 added support for emitting AvailableExternally Linkage on AIX. However, an assertion of "Trying to get csect representation of this symbol but none was set." occurred when a function is declared as available_externally. This is due to we missing to generate a csect for the function. This patch fixes it.
Reviewed By: hubert.reinterpretcast, shchenz
Differential Revision: https://reviews.llvm.org/D156213
Signed-off-by: Esme Yi <esme.yi@ibm.com>
And also set the SHF_X86_64_LARGE section flag.
gcc only uses the "l" prefix and SHF_X86_64_LARGE in the medium code model for data larger than -mlarge-data-threshold. But it seems more consistent to use it in the large code model as well in case separate parts of the binary aren't compiled with the large code model and also have a .data/.bss/.rodata section.
Reviewed By: MaskRay, tkoeppe
Differential Revision: https://reviews.llvm.org/D148836
The kernel and kext environments do not provide the `__cxa_atexit()`
function, so we can't use it for lowering global module destructors.
Unfortunately, just querying for "compiling for kernel/kext?" in the LTO
pipeline isn't possible (kernel/kext identifier isn't part of the triple
yet) so we need to pass down a CodeGen flag.
rdar://93536111
Differential Revision: https://reviews.llvm.org/D148967
This patch adds an `llc` option `-mroptr` to specify storage locations for constant pointers on AIX.
When the `-mroptr` option is specified, constant pointers, virtual function tables, and virtual type tables are placed in read-only storage. Otherwise, by default, pointers, virtual function tables, and virtual type tables are placed are placed in read/write storage.
https://reviews.llvm.org/D144190 enables the `-mroptr` option for `clang`.
Reviewed By: hubert.reinterpretcast, stephenpeckham, myhsu, MaskRay, serge-sans-paille
Differential Revision: https://reviews.llvm.org/D144189
Remove the `-lower-global-dtors-via-cxa-atexit` escape hatch introduced
in D121736 [1], which switched the default lowering of global
destructors on MachO to use `__cxa_atexit()` to avoid emitting
deprecated `__mod_term_func` sections.
I added this flag as an escape hatch in case the switch causes any
problems. We didn't discover any problems so now we can remove it.
[1] https://reviews.llvm.org/D121736
rdar://90277838
Differential Revision: https://reviews.llvm.org/D145715
These attributes have been accepted in ELF for a while, and are generated by
Clang in some places, so it makes sense to support them on MachO too.
https://reviews.llvm.org/D143173
Put jump table in .rdata for Windows to align with that for Linux.
It can avoid loading the same code page into I$ and D$ simultaneously
and thus favor performance.
Differential Revision: https://reviews.llvm.org/D144701
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 unneeded for small code model since "Max text segment
size < 2GiB" but making `-fno-pic -mcmodel={tiny,small}` different seems
unnecessary: 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.
)
---
Two clang/test/Interpreter tests would fail without 6747fc07d1aa94e22622e278e5a02ba70675ac9b
([ORC] Use JITLink as the default linker for LLJIT on Linux/arm64.)
Reviewed By: MatzeB
Differential Revision: https://reviews.llvm.org/D143039
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
