Summary:
MSVC and LLD sort sections ASCII-betically, so we need to use section
names that sort between .CRT$XCA (the start) and .CRT$XCU (the default
priority).
In the general case, use .CRT$XCT12345 as the section name, and let the
linker sort the zero-padded digits.
Users with low priorities typically want to initialize as early as
possible, so use .CRT$XCA00199 for prioties less than 200. This number
is arbitrary.
Implements PR38552.
Reviewers: majnemer, mstorsjo
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D51820
llvm-svn: 341727
I am experimenting with a single split dwarf (.dwo sections in .o files).
I want to make linker to ignore .dwo sections in .o, for that I am trying to add
SHF_EXCLUDE flag ("E") for them in my asm sample.
I found that currently, it is impossible to add any flag for debug sections using llvm-mc.
That happens because we have a set of predefined unique sections created early with default flags:
https://github.com/llvm-mirror/llvm/blob/master/lib/MC/MCObjectFileInfo.cpp#L391
This patch allows a user to add any flags he wants.
I had to edit TargetLoweringObjectFileImpl.cpp to set MetaData type for debug sections.
Their kind was Data by default (so they were allocatable) and so after changes introduced by
this patch the SHF_ALLOC flag was applied for them, what does not make sense for debug sections.
One of OrcJITTests tests failed because of that.
Differential revision: https://reviews.llvm.org/D51361
llvm-svn: 340904
Fixes PR37524.
The exception handling encodings for x86_64 in kernel code model
has been changed with r309884. Restore it to correct ones. These
encodings include PersonalityEncoding, LSDAEncoding and
TTypeEncoding.
Differential Revision: https://reviews.llvm.org/D50490
llvm-svn: 339534
Summary:
The TType encoding, LSDA encoding, and personality encoding are all
passed explicitly by CodeGen to the assembler through .cfi_* directives,
so only the AsmPrinter needs to know about them.
The FDE CFI encoding however, controls the encoding of the label
implicitly created by the .cfi_startproc directive. That directive seems
to be special in that it doesn't take an encoding, so the assembler just
has to know how to encode one DSO-local label reference from .eh_frame
to .text.
As a result, it looks like MC will continue to have to know when the
large code model is in use. Perhaps we could invent a '.cfi_startproc
[large]' flag so that this knowledge doesn't need to pollute the
assembler.
Reviewers: davide, lliu0, JDevlieghere
Subscribers: hiraditya, fedor.sergeev, llvm-commits
Differential Revision: https://reviews.llvm.org/D50533
llvm-svn: 339397
This reverts commit r337951.
While that kind of shared constant generally works fine in a MinGW
setting, it broke some cases of inline assembly that worked before:
$ cat const-asm.c
int MULH(int a, int b) {
int rt, dummy;
__asm__ (
"imull %3"
:"=d"(rt), "=a"(dummy)
:"a"(a), "rm"(b)
);
return rt;
}
int func(int a) {
return MULH(a, 1);
}
$ clang -target x86_64-win32-gnu -c const-asm.c -O2
const-asm.c:4:9: error: invalid variant '00000001'
"imull %3"
^
<inline asm>:1:15: note: instantiated into assembly here
imull __real@00000001(%rip)
^
A similar error is produced for i686 as well. The same test with a
target of x86_64-win32-msvc or i686-win32-msvc works fine.
llvm-svn: 338018
GNU binutils tools have no problems with this kind of shared constants,
provided that we actually hook it up completely in AsmPrinter and
produce a global symbol.
This effectively reverts SVN r335918 by hooking the rest of it up
properly.
This feature was implemented originally in SVN r213006, with no reason
for why it can't be used for MinGW other than the fact that GCC doesn't
do it while MSVC does.
Differential Revision: https://reviews.llvm.org/D49646
llvm-svn: 337951
This actually has nothing to do with the associative comdat sections
that aren't supported by GNU binutils ld.
Clarify the comments from SVN r335918 and use a separate flag for it.
Differential Revision: https://reviews.llvm.org/D49645
llvm-svn: 337757
This fixes a regression since SVN r334523, where the object files
built targeting MinGW were rejected by GNU binutils tools. Prior to
that commit, we only put constants in comdat for MSVC configurations.
Differential Revision: https://reviews.llvm.org/D48567
llvm-svn: 335918
=== Generating the CG Profile ===
The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.
After scanning all the functions, it generates an appending module flag containing the data. The format looks like:
```
!llvm.module.flags = !{!0}
!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}
```
Differential Revision: https://reviews.llvm.org/D48105
llvm-svn: 335794
This is the first pass in the main pipeline to use the legacy PM's
ability to run function analyses "on demand". Unfortunately, it turns
out there are bugs in that somewhat-hacky approach. At the very least,
it leaks memory and doesn't support -debug-pass=Structure. Unclear if
there are larger issues or not, but this should get the sanitizer bots
back to green by fixing the memory leaks.
llvm-svn: 335320
This patch adds support for generating a call graph profile from Branch Frequency Info.
The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.
After scanning all the functions, it generates an appending module flag containing the data. The format looks like:
!llvm.module.flags = !{!0}
!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}
Differential Revision: https://reviews.llvm.org/D48105
llvm-svn: 335306
Summary:
GCC and the binutils COFF linker do comdats differently from MSVC.
If we want to be ABI compatible, we have to do what they do, which is to
emit unique section names like ".text$_Z3foov" instead of short section
names like ".text". Otherwise, the binutils linker gets confused and
reports multiple definition errors when two object files from GCC and
Clang containing the same inline function are linked together.
The best description of the issue is probably at
https://github.com/Alexpux/MINGW-packages/issues/1677, we don't seem to
have a good one in our tracker.
I fixed up the .pdata and .xdata sections needed everywhere other than
32-bit x86. GCC doesn't use associative comdats for those, it appears to
rely on the section name.
Reviewers: smeenai, compnerd, mstorsjo, martell, mati865
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D48402
llvm-svn: 335286
WebAssembly doesn't support more than one function per section
and we rely on function sections being unique. This change ignores
the section provided by the function to avoid two functions being
in the same section.
Without this change the object writer produces the following
error for this test:
LLVM ERROR: section already has a defining function: baz
Differential Revision: https://reviews.llvm.org/D48178
llvm-svn: 334752
All COFF targets should use @IMGREL32 relocations for symbol differences
against __ImageBase. Do the same for getSectionForConstant, so that
immediates lowered to globals get merged across TUs.
Patch by Chris January
Differential Revision: https://reviews.llvm.org/D47783
llvm-svn: 334523
Summary:
Darwin dynamic linker can handle weak symbols in ConstDataSection.
ReadonReadOnlyWithRel symbols should be emitted in ConstDataSection
instead of normal DataSection.
rdar://problem/39298457
Reviewers: dexonsmith, kledzik
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45472
llvm-svn: 329752
Introduce an extension to support passing linker options to the linker.
These would be ignored by older linkers, but newer linkers which support
this feature would be able to process the linker.
Emit a special discarded section `.linker-option`. The content of this
section is a pair of strings (key, value). The key is a type identifier for
the parameter. This allows for an argument free parameter that will be
processed by the linker with the value being the parameter. As an example,
`lib` identifies a library to be linked against, traditionally the `-l`
argument for Unix-based linkers with the parameter being the library name.
Thanks to James Henderson, Cary Coutant, Rafael Espinolda, Sean Silva
for the valuable discussion on the design of this feature.
llvm-svn: 323783
`llvm.used` contains a list of pointers to named values which the
compiler, assembler, and linker are required to treat as if there is a
reference that they cannot see. Ensure that the symbols are preserved
by adding an explicit `-include` reference to the linker command.
llvm-svn: 323017
Summary:
- lowers @llvm.global_dtors by adding @llvm.global_ctors
functions which register the destructors with `__cxa_atexit`.
- impements @llvm.global_ctors with wasm start functions and linker metadata
See [here](https://github.com/WebAssembly/tool-conventions/issues/25) for more background.
Subscribers: jfb, dschuff, mgorny, jgravelle-google, aheejin, sunfish
Differential Revision: https://reviews.llvm.org/D41211
llvm-svn: 320774
Currently, when creating a named section, the Wasm
frontend forces it to use `SectionKind::Data`, whereas
in fact C++ does generate code sections with custom
names.
Patch by Nicholas Wilson
Differential Revision: https://reviews.llvm.org/D40906
llvm-svn: 320002
The priorities in the section name suffixes are zero padded,
allowing the linker to just do a lexical sort.
Add zero padding for .ctors sections in ELF as well.
Differential Revision: https://reviews.llvm.org/D40407
llvm-svn: 319150
For now at least. We clearly need some kind of comdat or
linkonce_odr support for wasm but currently COMDAT is not
supported.
Disable COMDAT support in the same way we do the Mach-O. This
also causes clang not to generated COMDATs.
Differential Revision: https://reviews.llvm.org/D39873
llvm-svn: 318123
This means that we can honor -fdata-sections rather than
always creating a segment for each symbol.
It also allows for a followup change to add .init_array and friends.
Differential Revision: https://reviews.llvm.org/D37876
llvm-svn: 313395
Looks like these were copied from the ELF sections but
don't apply to Wasm and were not used anywhere.
Also remove unused Wasm methods in MCContext.
Differential Revision: https://reviews.llvm.org/D37633
llvm-svn: 313058
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
This ensures that we can emit the ObjC Image Info structure on COFF and
ELF as well. The frontend already would attempt to emit this
information but would get dropped when generating assembly or an object
file.
llvm-svn: 304736
This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""
Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33413
llvm-svn: 304704
This is a version of D32090 that unifies all of the
`getInstrProf*SectionName` helper functions. (Note: the build failures
which D32090 would have addressed were fixed with r300352.)
We should unify these helper functions because they are hard to use in
their current form. E.g we recently introduced more helpers to fix
section naming for COFF files. This scheme doesn't totally succeed at
hiding low-level details about section naming, so we should switch to an
API that is easier to maintain.
This is not an NFC commit because it fixes llvm-cov's testing support
for COFF files (this falls out of the API change naturally). This is an
area where we lack tests -- I will see about adding one as a follow up.
Testing: check-clang, check-profile, check-llvm.
Differential Revision: https://reviews.llvm.org/D32097
llvm-svn: 300381
This is an ELF-specific thing that adds SHF_LINK_ORDER to the global's section
pointing to the metadata argument's section. The effect of that is a reverse dependency
between sections for the linker GC.
!associated does not change the behavior of global-dce. The global
may also need to be added to llvm.compiler.used.
Since SHF_LINK_ORDER is per-section, !associated effectively enables
fdata-sections for the affected globals, the same as comdats do.
Differential Revision: https://reviews.llvm.org/D29104
llvm-svn: 298157
With the "wasm32-unknown-unknown-wasm" triple, this allows writing out
simple wasm object files, and is another step in a larger series toward
migrating from ELF to general wasm object support. Note that this code
and the binary format itself is still experimental.
llvm-svn: 296190
