Variables with linkonce_odr and weak_odr linkage shouldn't be internalized
if they're not readonly. Otherwise we may end up with multiple copies of
such variable, so reads and writes will become inconsistent
Differential revision: https://reviews.llvm.org/D61255
llvm-svn: 360577
Summary:
We hit undefined references building with ThinLTO when one source file
contained explicit instantiations of a template method (weak_odr) but
there were also implicit instantiations in another file (linkonce_odr),
and the latter was the prevailing copy. In this case the symbol was
marked hidden when the prevailing linkonce_odr copy was promoted to
weak_odr. It led to unsats when the resulting shared library was linked
with other code that contained a reference (expecting to be resolved due
to the explicit instantiation).
Add a CanAutoHide flag to the GV summary to allow the thin link to
identify when all copies are eligible for auto-hiding (because they were
all originally linkonce_odr global unnamed addr), and only do the
auto-hide in that case.
Most of the changes here are due to plumbing the new flag through the
bitcode and llvm assembly, and resulting test changes. I augmented the
existing auto-hide test to check for this situation.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, dexonsmith, arphaman, dang, llvm-commits, steven_wu, wmi
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59709
llvm-svn: 360466
This restores part of r359311 that was reverted by r359830.
Rewrite the symbol types to fix several issues.
Notable difference is that the type of __init_array_start changes from
't' to 'd'.
GNU nm used to mark ELF symbols relative to .init_array as 't'
https://sourceware.org/bugzilla/show_bug.cgi?id=24505 (before 2.33)
because ".init" is the prefix. The bug was copied by r287803.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D61551
llvm-svn: 360339
-t is --symbols in llvm-readobj but --section-details (unimplemented) in readelf.
The confusing option should not be used since we aim for improving
compatibility.
Keep just one llvm-readobj -t use case in test/tools/llvm-readobj/symbols.test
llvm-svn: 359661
Summary:
For ThinLTOCodegenerator, it has an option to save the object file
outputs into a directory which is essential for debug info. Tools like lldb
and dsymutil will look for these object files for debug info.
On Darwin platform, you can link fat binaries with one single clang
driver invocation like:
$ clang -arch x86_64 -arch i386 -Wl,-object_path_lto,$TMPDIR ...
Unfornately, the output object files for one architecture is going to
overwrite the previous ones and one architecture slice will end up with
no debug info. One example for this is to turn on ThinLTO for sanitizer
dylibs in compiler-rt project.
To fix the issue, add the name for the architecture into the name of the
output object file.
rdar://problem/35482935
Reviewers: tejohnson, bd1976llvm, dexonsmith, JDevlieghere
Reviewed By: dexonsmith
Subscribers: mehdi_amini, aprantl, inglorion, eraman, hiraditya, jkorous, dang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60924
llvm-svn: 359508
Summary:
Reapply r357931 with fixes to ThinLTO testcases and llvm-lto tool.
ThinLTOCodeGenerator currently does not preserve llvm.used symbols and
it can internalize them. In order to pass the necessary information to the
legacy ThinLTOCodeGenerator, the input to the code generator is
rewritten to be based on lto::InputFile.
Now ThinLTO using the legacy LTO API will requires data layout in
Module.
"internalize" thinlto action in llvm-lto is updated to run both
"promote" and "internalize" with the same configuration as
ThinLTOCodeGenerator. The old "promote" + "internalize" option does not
produce the same output as ThinLTOCodeGenerator.
This fixes: PR41236
rdar://problem/49293439
Reviewers: tejohnson, pcc, kromanova, dexonsmith
Reviewed By: tejohnson
Subscribers: ormris, bd1976llvm, mehdi_amini, inglorion, eraman, hiraditya, jkorous, dexonsmith, arphaman, dang, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60421
llvm-svn: 358601
Summary:
The AliasSummary previously contained the AliaseeGUID, which was only
populated when reading the summary from bitcode. This patch changes it
to instead hold the ValueInfo of the aliasee, and always populates it.
This enables more efficient access to the ValueInfo (specifically in the
recent patch r352438 which needed to perform an index hash table lookup
using the aliasee GUID).
As noted in the comments in AliasSummary, we no longer technically need
to keep a pointer to the corresponding aliasee summary, since it could
be obtained by walking the list of summaries on the ValueInfo looking
for the summary in the same module. However, I am concerned that this
would be inefficient when walking through the index during the thin
link for various analyses. That can be reevaluated in the future.
By always populating this new field, we can remove the guard and special
handling for a 0 aliasee GUID when dumping the dot graph of the summary.
An additional improvement in this patch is when reading the summaries
from LLVM assembly we now set the AliaseeSummary field to the aliasee
summary in that same module, which makes it consistent with the behavior
when reading the summary from bitcode.
Reviewers: pcc, mehdi_amini
Subscribers: inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D57470
llvm-svn: 356268
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
Original llvm-svn: 355964
llvm-svn: 355984
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
llvm-svn: 355964
Summary:
The changes to disable LTO unit splitting by default (r350949) and
detect inconsistently split LTO units (r350948) are causing some crashes
when the inconsistency is detected in multiple threads simultaneously.
Fix that by having the code always look for the inconsistently split
LTO units during the thin link, by checking for the presence of type
tests recorded in the summaries.
Modify test added in r350948 to remove single threading required to fix
a bot failure due to this issue (and some debugging options added in the
process of diagnosing it).
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57561
llvm-svn: 354062
New test added in r352441 getting a bot failure which I believe is
due to different ordering in the dumping which isn't being handled
well. Try to make test more resilient to ordering differences.
llvm-svn: 352446
Summary:
I found that there currently isn't a way to invoke exportToDot from
the command line for a per-module summary index, and therefore no
testing of that case. Add an internal option and use it to test dumping
of per module summary indexes.
In particular, I am looking at fixing the limitation that causes the
aliasee GUID in the per-module summary to be 0, and want to be able to
test that change.
Reviewers: evgeny777
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D57206
llvm-svn: 352441
An abstract call site is a wrapper that allows to treat direct,
indirect, and callback calls the same. If an abstract call site
represents a direct or indirect call site it behaves like a stripped
down version of a normal call site object. The abstract call site can
also represent a callback call, thus the fact that the initially
called function (=broker) may invoke a third one (=callback callee).
In this case, the abstract call side hides the middle man, hence the
broker function. The result is a representation of the callback call,
inside the broker, but in the context of the original instruction that
invoked the broker.
Again, there are up to three functions involved when we talk about
callback call sites. The caller (1), which invokes the broker
function. The broker function (2), that may or may not invoke the
callback callee. And finally the callback callee (3), which is the
target of the callback call.
The abstract call site will handle the mapping from parameters to
arguments depending on the semantic of the broker function. However,
it is important to note that the mapping is often partial. Thus, some
arguments of the call/invoke instruction are mapped to parameters of
the callee while others are not. At the same time, arguments of the
callback callee might be unknown, thus "null" if queried.
This patch introduces also !callback metadata which describe how a
callback broker maps from parameters to arguments. This metadata is
directly created by clang for known broker functions, provided through
source code attributes by the user, or later deduced by analyses.
For motivation and additional information please see the corresponding
talk (slides/video)
https://llvm.org/devmtg/2018-10/talk-abstracts.html#talk20
as well as the LCPC paper
http://compilers.cs.uni-saarland.de/people/doerfert/par_opt_lcpc18.pdf
Differential Revision: https://reviews.llvm.org/D54498
llvm-svn: 351627
Summary:
If LTOUnit splitting is disabled, the module summary analysis computes
the summary information necessary to perform single implementation
devirtualization during the thin link with the index and no IR. The
information collected from the regular LTO IR in the current hybrid WPD
algorithm is summarized, including:
1) For vtable definitions, record the function pointers and their offset
within the vtable initializer (subsumes the information collected from
IR by tryFindVirtualCallTargets).
2) A record for each type metadata summarizing the vtable definitions
decorated with that metadata (subsumes the TypeIdentiferMap collected
from IR).
Also added are the necessary bitcode records, and the corresponding
assembly support.
The index-based WPD will be sent as a follow-on.
Depends on D53890.
Reviewers: pcc
Subscribers: mehdi_amini, Prazek, inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54815
llvm-svn: 351453
Summary:
Records in the module summary index whether the bitcode was compiled
with the option necessary to enable splitting the LTO unit
(e.g. -fsanitize=cfi, -fwhole-program-vtables, or -fsplit-lto-unit).
The information is passed down to the ModuleSummaryIndex builder via a
new module flag "EnableSplitLTOUnit", which is propagated onto a flag
on the summary index.
This is then used during the LTO link to check whether all linked
summaries were built with the same value of this flag. If not, an error
is issued when we detect a situation requiring whole program visibility
of the class hierarchy. This is the case when both of the following
conditions are met:
1) We are performing LowerTypeTests or Whole Program Devirtualization.
2) There are type tests or type checked loads in the code.
Note I have also changed the ThinLTOBitcodeWriter to also gate the
module splitting on the value of this flag.
Reviewers: pcc
Subscribers: ormris, mehdi_amini, Prazek, inglorion, eraman, steven_wu, dexonsmith, arphaman, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D53890
llvm-svn: 350948
Summary:
Alias can make one (but not all) live, we still need to scan all others if this symbol is reachable
from somewhere else.
Reviewers: tejohnson, grimar
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D56117
llvm-svn: 350269
The current llvm.mem.parallel_loop_access metadata has a problem in that
it uses LoopIDs. LoopID unfortunately is not loop identifier. It is
neither unique (there's even a regression test assigning the some LoopID
to multiple loops; can otherwise happen if passes such as LoopVersioning
make copies of entire loops) nor persistent (every time a property is
removed/added from a LoopID's MDNode, it will also receive a new LoopID;
this happens e.g. when calling Loop::setLoopAlreadyUnrolled()).
Since most loop transformation passes change the loop attributes (even
if it just to mark that a loop should not be processed again as
llvm.loop.isvectorized does, for the versioned and unversioned loop),
the parallel access information is lost for any subsequent pass.
This patch unlinks LoopIDs and parallel accesses.
llvm.mem.parallel_loop_access metadata on instruction is replaced by
llvm.access.group metadata. llvm.access.group points to a distinct
MDNode with no operands (avoiding the problem to ever need to add/remove
operands), called "access group". Alternatively, it can point to a list
of access groups. The LoopID then has an attribute
llvm.loop.parallel_accesses with all the access groups that are parallel
(no dependencies carries by this loop).
This intentionally avoid any kind of "ID". Loops that are clones/have
their attributes modifies retain the llvm.loop.parallel_accesses
attribute. Access instructions that a cloned point to the same access
group. It is not necessary for each access to have it's own "ID" MDNode,
but those memory access instructions with the same behavior can be
grouped together.
The behavior of llvm.mem.parallel_loop_access is not changed by this
patch, but should be considered deprecated.
Differential Revision: https://reviews.llvm.org/D52116
llvm-svn: 349725
Summary:
This patch computes the synthetic function entry count on the whole
program callgraph (based on module summary) and writes the entry counts
to the summary. After function importing, this count gets attached to
the IR as metadata. Since it adds a new field to the summary, this bumps
up the version.
Reviewers: tejohnson
Subscribers: mehdi_amini, inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D43521
llvm-svn: 349076
It looks like this isn't necessary (in any tests I've done, it results
in the global being described with no location or value in the imported
side - while it's still fully described in the place it's imported from)
& results in significant/pathological debug info growth to home these
location-less global variable descriptions on the import side.
This is a rather pressing/important issue to address - this regressed
executable size for one example I'm looking at by 15%, object size is probably
similar though I haven't measured it, and a 22x increase in the number of CUs
in the cu_index in split DWARF DWP files, creating a similarly large regression
in the time it takes llvm-symbolizer to run on such binaries.
Reviewers: tejohnson, evgeny777
Differential Revision: https://reviews.llvm.org/D55309
llvm-svn: 348416
Skip the ThinLTO cache tests on NetBSD. They require 'touch' being
able to alter atime of files, while NetBSD inhibits atime updates
when filesystem is mounted noatime.
Differential Revision: https://reviews.llvm.org/D55273
llvm-svn: 348355
Without this, we don't consider types used by aliasees in our cache key.
This caused issues when using the same cache for thin-linking the same
TU with different sets of virtual call candidates for a virtual call
inside of a constructor. That's sort of a mouthful. :)
Differential Revision: https://reviews.llvm.org/D55060
llvm-svn: 348216
Summary:
We can sometimes end up with multiple copies of a local variable that
have the same GUID in the index. This happens when there are local
variables with the same name that are in different source files having the
same name/path at compile time (but compiled into different bitcode objects).
In this case make sure we import the copy in the caller's module.
This enables importing both of the variables having the same GUID
(but which will have different promoted names since the module paths,
and therefore the module hashes, will be distinct).
Importing the wrong copy is particularly problematic for read only
variables, since we must import them as a local copy whenever
referenced. Otherwise we get undefs at link time.
Note that the llvm-lto.cpp and ThinLTOCodeGenerator changes are needed
for testing the distributed index case via clang, which will be sent as
a separate clang-side patch shortly. We were previously not doing the
dead code/read only computation before computing imports when testing
distributed index generation (like it was for testing importing and
other ThinLTO mechanisms alone).
Reviewers: evgeny777
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D55047
llvm-svn: 347886
Summary:
Follow up to D49362 ([ThinLTO] Internalize read only globals). Add a
statistic on the number of read only variables (only counting live
variables since dead variables will be dropped anyway).
Reviewers: evgeny777
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54642
llvm-svn: 347145
An attempt to recommit r346584 after failure on OSX build bot.
Fixed cache key computation in ThinLTOCodeGenerator and added
test case
llvm-svn: 347033
This is a revised version of D41474.
When the debug location is parsed in BitcodeReader::parseFunction, the
scope and inlinedAt MDNodes are obtained via MDLoader->getMDNodeFwdRefOrNull(),
which will create a forward ref if they were not yet loaded.
Specifically, if one of these MDNodes is in the module level metadata
block, and this is during ThinLTO importing, that metadata block is
lazily loaded.
Most places in that invoke getMDNodeFwdRefOrNull have a corresponding call
to resolveForwardRefsAndPlaceholders which will take care of resolving them.
E.g. places that call getMetadataFwdRefOrLoad, or at the end of parsing a
function-level metadata block, or at the end of the initial lazy load of
module level metadata in order to handle invocations of getMDNodeFwdRefOrNull
for named metadata and global object attachments. However, the calls for
the scope/inlinedAt of debug locations are not backed by any such call to
resolveForwardRefsAndPlaceholders.
To fix this, change the scope and inlinedAt parsing to instead use
getMetadataFwdRefOrLoad, which will ensure the forward refs to lazily
loaded metadata are resolved.
Fixes PR35472.
llvm-svn: 346891
This patch allows internalising globals if all accesses to them
(from live functions) are from non-volatile load instructions
Differential revision: https://reviews.llvm.org/D49362
llvm-svn: 346584
Summary:
This fixes PR 37422
In ELF, non-weak symbols can also be non-prevailing. In this particular
PR, the __llvm_profile_* symbols are non-prevailing but weren't getting
dropped - causing multiply-defined errors with lld.
Also add a test, strong_non_prevailing.ll, to ensure that multiple
copies of a strong symbol are dropped.
To fix the test regressions exposed by this fix,
- do not mark prevailing copies for symbols with 'appending' linkage.
There's no one prevailing copy for such symbols.
- fix the prevailing version in dead-strip-fulllto.ll
- explicitly pass exported symbols to llvm-lto in fumcimport.ll and
funcimport_var.ll
Reviewers: tejohnson, pcc
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith,
dang, srhines, llvm-commits
Differential Revision: https://reviews.llvm.org/D54125
llvm-svn: 346436
Summary:
The NotEligibleToImport flag on the GlobalValueSummary was set if it
isn't legal to import (e.g. because it references unpromotable locals)
and when it can't be inlined (in which case importing is pointless).
I split out the inlinable piece into a separate flag on the
FunctionSummary (doesn't make sense for aliases or global variables),
because in the future we may want to import for reasons other than
inlining.
Reviewers: davidxl
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D53345
llvm-svn: 346261
Summary:
LTO and ThinLTO optimizes the IR differently.
One source of differences is the amount of internalizations that
can happen.
Add an option to enable/disable internalization so that other
differences can be studied in isolation. e.g. inlining.
There are other things lto and thinlto do differently, I will add
flags to enable/disable them as needed.
Reviewers: tejohnson, pcc, steven_wu
Subscribers: mehdi_amini, inglorion, steven_wu, dexonsmith, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D53294
llvm-svn: 346140
ModuleSummaryIndex::exportToDot crashes when linking the Linux kernel
under ThinLTO using LLVMgold.so. This is due to the exportToDot
function trying to get the GUID of an empty ValueInfo. The root cause
related to the fact that we attempt to get the GUID of an aliasee
via its OriginalGUID recorded in the aliasee summary, and that is not
always possible. Specifically, we cannot do this mapping when the value
is internal linkage and there were other internal linkage symbols with
the same name.
There are 2 fixes for the problem included here.
1) In all cases where we can currently print the dot file from the
command line (which is only via save-temps), we have a valid AliaseeGUID
in the AliasSummary. Use that when it is available, so that we can get
the correct aliasee GUID whenever possible.
2) However, if we were to invoke exportToDot from the debugger right
after it is built during the initial analysis step (i.e. the per-module
summary), we won't have the AliaseeGUID field populated. In that case,
we have a fallback fix that will simply print "@"+GUID when we aren't
able to get the GUID from the OriginalGUID. It simply checks if the VI
is valid or not before attempting to get the name. Additionally, since
getAliaseeGUID will assert that the AliaseeGUID is non-zero, guard the
earlier fix#1 by a new function hasAliaseeGUID().
Reviewers: pcc, tmroeder
Subscribers: evgeny777, mehdi_amini, inglorion, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D53986
llvm-svn: 346055
Summary:
This is a revised version of D41474.
When the debug location is parsed in BitcodeReader::parseFunction, the
scope and inlinedAt MDNodes are obtained via MDLoader->getMDNodeFwdRefOrNull(),
which will create a forward ref if they were not yet loaded.
Specifically, if one of these MDNodes is in the module level metadata
block, and this is during ThinLTO importing, that metadata block is
lazily loaded.
Most places in that invoke getMDNodeFwdRefOrNull have a corresponding call
to resolveForwardRefsAndPlaceholders which will take care of resolving them.
E.g. places that call getMetadataFwdRefOrLoad, or at the end of parsing a
function-level metadata block, or at the end of the initial lazy load of
module level metadata in order to handle invocations of getMDNodeFwdRefOrNull
for named metadata and global object attachments. However, the calls for
the scope/inlinedAt of debug locations are not backed by any such call to
resolveForwardRefsAndPlaceholders.
To fix this, change the scope and inlinedAt parsing to instead use
getMetadataFwdRefOrLoad, which will ensure the forward refs to lazily
loaded metadata are resolved.
Fixes PR35472.
Reviewers: dexonsmith, Sunil_Srivastava, vsk
Subscribers: inglorion, eraman, steven_wu, sebpop, mehdi_amini, dmikulin, vsk, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D53596
llvm-svn: 345095
Summary:
D45602 added this to most tools, including llvm-lto, but not to
llvm-lto2. Add it there and test that it works in both lto tools.
Reviewers: ruiu
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D53330
llvm-svn: 344631
Summary:
If we have a symbol with (linkonce|weak)_odr linkage, we do not want
to dead strip it even it is not prevailing.
IR level (linkonce|weak)_odr symbol can become non-prevailing when we mix
ELF objects and IR objects where the (linkonce|weak)_odr symbol in the ELF
object is prevailing and the ones in the IR objects are not. Stripping
them will prevent us from doing optimizations with them.
By not dead stripping them, We will convert these symbols to
available_externally linkage as a result of non-prevailing and eventually
dropping them after inlining.
I modified cache-prevailing.ll to use linkonce linkage as it is
testing whether cache prevailing bit is effective or not, not
we should treat linkonce_odr alive or not
Reviewers: tejohnson, pcc
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D52893
llvm-svn: 343970
