As of r323633, this bit started controlling whether symbol definitions
appear in object files, and it also became sensitive to the prevailing
bit, so it needs to be included in the key.
Differential Revision: https://reviews.llvm.org/D43109
llvm-svn: 324711
Summary:
This complements the fixes in r323633 and r324075 which drop the
definitions of dead functions and variables, respectively.
Fixes PR36208.
Reviewers: grimar, rafael
Subscribers: mehdi_amini, llvm-commits, inglorion
Differential Revision: https://reviews.llvm.org/D42856
llvm-svn: 324242
This fixes PR36187.
Patch teaches ThinLTO to drop non-prevailing variables,
just like we recently did for functions (in r323633).
Differential revision: https://reviews.llvm.org/D42798
llvm-svn: 324075
LTO sets dso_local as an optimization, so don't clear it.
This avoid clearing it from undefined hidden symbols, which would then
fail the verifier.
llvm-svn: 322814
While updating clang tests for having clang set dso_local I noticed
that:
- There are *a lot* of tests to update.
- Many of the updates are redundant.
They are redundant because a GV is "obviously dso_local". This patch
starts formalizing that a bit by requiring that internal and private
GVs be dso_local too. Since they all are, we don't have to print
dso_local to the textual representation, making it a bit more compact
and easier to read.
llvm-svn: 322317
Summary:
1. Use stream 0 only for combined module. Previously if combined module was not
processes ThinLTO used the stream for own output. However small changes in input,
could trigger combined module and shuffle outputs making life of llvm::LTO harder.
2. Always process combined module and write output to stream 0. Processing empty
combined module is cheap and allows llvm::LTO users to avoid implementing processing
which is already done in llvm::LTO.
Subscribers: mehdi_amini, inglorion, eraman, hiraditya
Differential Revision: https://reviews.llvm.org/D41267
llvm-svn: 320905
Change the representation of COFF comdats so that a COFF linker
is able to accurately resolve comdats between IR and native object
files. Specifically, apply name mangling to comdat names consistently
with native object files, and do not export comdats with an internal
leader because they do not affect symbol resolution.
Differential Revision: https://reviews.llvm.org/D40278
llvm-svn: 318805
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.
Originally commited as r317374, but reverted in r317395 to update some missed
tests.
Differential Revision: https://reviews.llvm.org/D35702
llvm-svn: 317408
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.
Differential Revision: https://reviews.llvm.org/D35702
llvm-svn: 317374
This is necessary because DCE is applied to full LTO modules. Without
this change, a reference from a dead ThinLTO global to a dead full
LTO global will result in an undefined reference at link time.
This problem is only observable when --gc-sections is disabled, or
when targeting COFF, as the COFF port of lld requires all symbols to
have a definition even if all references are dead (this is consistent
with link.exe).
This change also adds an EliminateAvailableExternally pass at -O0. This
is necessary to handle the situation on Windows where a non-prevailing
copy of a linkonce_odr function has an SEH filter function; any
such filters must be DCE'd because they will contain a call to the
llvm.localrecover intrinsic, passing as an argument the address of the
function that the filter belongs to, and llvm.localrecover requires
this function to be defined locally.
Fixes PR35142.
Differential Revision: https://reviews.llvm.org/D39484
llvm-svn: 317108
This reland includes a fix for the LowerTypeTests pass so that it
looks past aliases when determining which type identifiers are live.
Differential Revision: https://reviews.llvm.org/D37842
llvm-svn: 313229
This broke Chromium's CFI build; see crbug.com/765004.
> We were previously handling aliases during dead stripping by adding
> the aliased global's "original name" GUID to the worklist. This will
> lead to incorrect behaviour if the global has local linkage because
> the original name GUID will not correspond to the global's GUID in
> the summary.
>
> Because an alias is just another name for the global that it
> references, there is no need to mark the referenced global as used,
> or to follow references from any other copies of the global. So all
> we need to do is to follow references from the aliasee's summary
> instead of the alias.
>
> Differential Revision: https://reviews.llvm.org/D37789
llvm-svn: 313222
We were previously handling aliases during dead stripping by adding
the aliased global's "original name" GUID to the worklist. This will
lead to incorrect behaviour if the global has local linkage because
the original name GUID will not correspond to the global's GUID in
the summary.
Because an alias is just another name for the global that it
references, there is no need to mark the referenced global as used,
or to follow references from any other copies of the global. So all
we need to do is to follow references from the aliasee's summary
instead of the alias.
Differential Revision: https://reviews.llvm.org/D37789
llvm-svn: 313157
Summary:
This updates the Inliner to only add a single Optimization
Remark when Inlining, rather than an Analysis Remark and an
Optimization Remark.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33786
Reviewers: anemet, davidxl, chandlerc
Reviewed By: anemet
Subscribers: haicheng, fhahn, mehdi_amini, dblaikie, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D36054
llvm-svn: 311349
Summary:
This updates the Inliner to only add a single Optimization
Remark when Inlining, rather than an Analysis Remark and an
Optimization Remark.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33786
Reviewers: anemet, davidxl, chandlerc
Reviewed By: anemet
Subscribers: haicheng, fhahn, mehdi_amini, dblaikie, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D36054
llvm-svn: 311273
We were previously creating a global variable of function type,
which is invalid IR. This issue was exposed by r304690, in which we
started asserting that global variables were of a valid type.
Fixes PR33462.
Differential Revision: https://reviews.llvm.org/D36438
llvm-svn: 310543
Summary: In ThinLTO backend compile, OPTOptions are not set so that the ICP in ThinLTO backend does not know if it is a SamplePGO build, in which profile count needs to be annotated directly on call instructions. This patch cleaned up the PGOOptions handling logic and passes down PGOOptions to ThinLTO backend.
Reviewers: chandlerc, tejohnson, davidxl
Reviewed By: chandlerc
Subscribers: sanjoy, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D36052
llvm-svn: 309780
Summary:
This exposes LTO's Conf.SampleProfile as a command line option
(-lto-sample-profile-file) for testing via the llvm-lto2 utility.
Reviewers: pcc, danielcdh
Subscribers: mehdi_amini, inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D36030
llvm-svn: 309456
If the LowerTypeTests pass decides to add a function to a jump
table for CFI, it will add its name to the set cfiFunctionDefs,
which among other things will cause the function to be renamed in
the ThinLTO backend.
One other thing that we must do with such functions is to not
internalize them, because the jump table in the full LTO object will
contain a reference to the actual function body in the ThinLTO object.
This patch handles that by ensuring that we export any functions
whose names appear in the cfiFunctionDefs set.
Fixes PR33831.
Differential Revision: https://reviews.llvm.org/D35605
llvm-svn: 308504
This is the same as r304719 but for ThinLTO.
The substantial difference is that in this case we don't have
whole visibility, just the summary.
In the LTO case, when we got the resolution for the input file we
could just see if the linker told us whether a symbol was linker
redefined (using --wrap or --defsym) and switch the linkage directly
for the GV.
Here, we have the summary. So, we record that the linkage changed
from <whatever it was> to $weakany to prevent IPOs across this symbol
boundaries and actually just switch the linkage at FunctionImport time.
This patch should also fixes the lld bits (as all the scaffolding for
communicating if a symbol is linker redefined should be there & should
be the same), but I'll make sure to add some tests there as well.
Fixes PR33192.
Differential Revision: https://reviews.llvm.org/D35064
llvm-svn: 307303
Summary:
When linking a regular LTO module, if it has any non-prevailing values
(dropped to available_externally) in comdats, we need to do more than
just remove those values from their comdat. We also remove all values
from that comdat, so as to avoid leaving an incomplete comdat.
This is necessary in case we are compiling in mixed regular and ThinLTO
mode, since the resulting regularLTO native object is always linked into
the final binary first. We need to prevent the linker from selecting an
incomplete comdat that was not the prevailing copy.
Fixes PR32980.
Reviewers: pcc, rafael
Subscribers: mehdi_amini, david2050, llvm-commits, inglorion
Differential Revision: https://reviews.llvm.org/D34803
llvm-svn: 306826
If a regular LTO module has a summary index, then instead of linking
it into the combined regular LTO module right away, add it to the
combined summary index and associate it with a special module that
represents the combined regular LTO module.
Any such modules are linked during LTO::run(), at which time we use
the results of summary-based dead stripping to control whether to
link prevailing symbols.
Differential Revision: https://reviews.llvm.org/D33922
llvm-svn: 305482
procedural optimizations to prevent dropping symbols and allow the linker
to process re-directs.
PR33145: --wrap doesn't work with lto.
Differential Revision: https://reviews.llvm.org/D33621
llvm-svn: 304719
The whole-program-devirt pass needs to run at -O0 because only it
knows about the llvm.type.checked.load intrinsic: it needs to both
lower the intrinsic itself and handle it in the summary.
Differential Revision: https://reviews.llvm.org/D33571
llvm-svn: 304019
Prevailing symbol resolution is necessary for correctness. Without
this we can end up dropping a referenced linkonce symbol from the link.
Differential Revision: https://reviews.llvm.org/D33570
llvm-svn: 303939
Summary:
All GlobalIndirectSymbol types (not just GlobalAlias) should return
their base object.
Without this patch LTO would warn "Unable to determine comdat of
alias!" for an ifunc.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D33202
llvm-svn: 303096
Marking them as used causes them to be considered visible outside of LTO. This
prevents the symbols from being internalized or discarded, either by GlobalDCE
or by summary-based dead stripping in ThinLTO.
This change makes it unnecessary to add these symbols to llvm.compiler.used
in the backend, as the symbols are kept alive by virtue of being external,
so remove the backend code that handles that.
Fixes PR32798.
Differential Revision: https://reviews.llvm.org/D32544
llvm-svn: 301438
Start using it in LLD to avoid needing to read bitcode again just to get the
target triple, and in llvm-lto2 to avoid printing symbol table information
that is inappropriate for the target.
Differential Revision: https://reviews.llvm.org/D32038
llvm-svn: 300300
Summary:
The linker needs to be able to determine whether a symbol is text or data to
handle the case of a common being overridden by a strong definition in an
archive. If the archive contains a text member of the same name as the common,
that function is discarded. However, if the archive contains a data member of
the same name, that strong definition overrides the common. This is a behavior
of ld.bfd, which the Qualcomm linker also supports in LTO.
Here's a test case to illustrate:
####
cat > 1.c << \!
int blah;
!
cat > 2.c << \!
int blah() {
return 0;
}
!
cat > 3.c << \!
int blah = 20;
!
clang -c 1.c
clang -c 2.c
clang -c 3.c
ar cr lib.a 2.o 3.o
ld 1.o lib.a -t
####
The correct output is:
1.o
(lib.a)3.o
Thanks to Shankar Easwaran and Hemant Kulkarni for the test case!
Reviewers: mehdi_amini, rafael, pcc, davide
Reviewed By: pcc
Subscribers: davide, llvm-commits, inglorion
Differential Revision: https://reviews.llvm.org/D31901
llvm-svn: 300205
Move LTO::run() to a "run" subcommand so that we can introduce new subcommands
for testing different parts of the LTO implementation.
This doesn't use llvm::cl subcommands because it doesn't appear to be currently
possible to pass an argument not associated with a subcommand to a subcommand
(e.g. -lto-use-new-pm, -mcpu=yonah).
Differential Revision: https://reviews.llvm.org/D31410
llvm-svn: 299967
Summary:
Add a field to LTO::Config, CGFileType, to select the file type to emit (object
or assembly). This is useful for testing and to implement -save-temps.
Reviewers: tejohnson, mehdi_amini, pcc
Reviewed By: mehdi_amini
Subscribers: davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D29475
llvm-svn: 295226
until we can get better TargetMachine::isCompatibleDataLayout to compare - otherwise
we can't code generate existing bitcode without a string equality data layout.
This reverts commit r294702.
llvm-svn: 294709
For other platforms we should find out what they need and likely
make the same change, however, a smaller additional change is easier
for platforms we know have it specified in the ABI. As part of this
rewrite some of the handling in the backends for data layout and update
a bunch of testcases.
Based on a patch by Simonas Kazlauskas!
llvm-svn: 294702
These linkages mean that the ultimately prevailing symbol will have the same
semantics as any non-prevailing copy of the symbol, so we are free to ignore
the linker's resolution.
Differential Revision: https://reviews.llvm.org/D29367
llvm-svn: 293865
Also, udpate the ~60 failing tests in the tree which did
not contain a valid datalayout.
This fixes PR31123. lld will be updated in a following patch,
immediately after this is committed.
Differential Revision: https://reviews.llvm.org/D27082
llvm-svn: 289719
Peter Collingbourne