This has been fixed in the "new" LTO API used by Gold/LLD, this is
fixing the same issue in the libLTO API used by ld64 (amongst other)
llvm-svn: 291518
Summary:
Using the linker-supplied list of "preserved" symbols, we can compute
the list of "dead" symbols, i.e. the one that are not reachable from
a "preserved" symbol transitively on the reference graph.
Right now we are using this information to mark these functions as
non-eligible for import.
The impact is two folds:
- Reduction of compile time: we don't import these functions anywhere
or import the function these symbols are calling.
- The limited number of import/export leads to better internalization.
Patch originally by Mehdi Amini.
Reviewers: mehdi_amini, pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23488
llvm-svn: 291177
Summary:
When reading the metadata bitcode, create a type declaration when
possible for composite types when we are importing. Doing this in
the bitcode reader saves memory. Also it works naturally in the case
when the type ODR map contains a definition for the same composite type
because it was used in the importing module (buildODRType will
automatically use the existing definition and not create a type
declaration).
For Chromium built with -g2, this reduces the aggregate size of the
generated native object files by 66% (from 31G to 10G). It reduced
the time through the ThinLTO link and backend phases by about 20% on
my machine.
Reviewers: mehdi_amini, dblaikie, aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27775
llvm-svn: 289993
Summary: ThinLTO needs to invoke SampleProfileLoader pass during link time in order to annotate profile correctly after module importing.
Reviewers: davidxl, mehdi_amini, tejohnson
Subscribers: pcc, davide, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D27790
llvm-svn: 289957
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
Summary:
The motivation is to support better the -object_path_lto option on
Darwin. The linker needs to write down the generate object files on
disk for later use by lldb or dsymutil (debug info are not present
in the final binary). We're moving this into libLTO so that we can
be smarter when a cache is enabled and hard-link when possible
instead of duplicating the files.
Reviewers: tejohnson, deadalnix, pcc
Subscribers: dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D27507
llvm-svn: 289631
Summary:
As discussed on mailing list, for ThinLTO importing we don't need
to import all the fields of the DICompileUnit. Don't import enums,
macros, retained types lists. Also only import local scoped imported
entities. Since we don't currently import any global variables,
we also don't need to import the list of global variables (added an
assert to verify none are being imported).
This is being done by pre-populating the value map entries to map
the unneeded metadata to nullptr. For the imported entities, we can
simply replace the source module's list with a new list containing
only those needed imported entities. This is done in the IRLinker
constructor so that value mapping automatically does the desired
mapping.
Reviewers: mehdi_amini, dexonsmith, dblaikie, aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27635
llvm-svn: 289441
Most importantly, we need to hash the relocation model, otherwise we can
end up trying to link non-PIC object files into PIEs or DSOs.
Differential Revision: https://reviews.llvm.org/D27556
llvm-svn: 289024
This class represents a symbol table built from in-memory IR. It provides
access to GlobalValues and should only be used if such access is required
(e.g. in the LTO implementation). We will eventually change IRObjectFile
to read from a bitcode symbol table rather than using ModuleSymbolTable,
so it would not be able to expose the module.
Differential Revision: https://reviews.llvm.org/D27073
llvm-svn: 288319
This is no longer the recommended way to load modules for importing, so it should not be public API.
Differential Revision: https://reviews.llvm.org/D27292
llvm-svn: 288316
Summary:
This will also be added to the LTO API, right now this will
bring ThinLTO on par with Monolithic LTO on Darwin.
Reviewers: anemet
Subscribers: tejohnson, llvm-commits
Differential Revision: https://reviews.llvm.org/D26886
llvm-svn: 287450
Summary:
This makes it explicit that ownership is taken. Also replace all `new`
with make_unique<> at call sites.
Reviewers: anemet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26884
llvm-svn: 287449
It is used to drive this from the clang driver via -mllvm.
Same option name is used as in opt.
Differential Revision: https://reviews.llvm.org/D26832
llvm-svn: 287356
This patch updates a bunch of places where add_dependencies was being explicitly called to add dependencies on intrinsics_gen to instead use the DEPENDS named parameter. This cleanup is needed for a patch I'm working on to add a dependency debugging mode to the build system.
llvm-svn: 287206
Summary:
We have always speculatively promoted all renamable local values
(except const non-address taken variables) for both the exporting
and importing module. We would then internalize them back based on
the ThinLink results if they weren't actually exported. This is
inefficient, and results in unnecessary renames. It also meant we
had to check the non-renamability of a value in the summary, which
was already checked during function importing analysis in the ThinLink.
Made renameModuleForThinLTO (which does the promotion/renaming) instead
use the index when exporting, to avoid unnecessary renames/promotions.
For importing modules, we can simply promoted all values as any local
we import by definition is exported and needs promotion.
This required changes to the method used by the FunctionImport pass
(only invoked from 'opt' for testing) and when invoked from llvm-link,
since neither does a ThinLink. We simply conservatively mark all locals
in the index as promoted, which preserves the current aggressive
promotion behavior.
I also needed to change an llvm-lto based test where we had previously
been aggressively promoting values that weren't importable (aliasees),
but now will not promote.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26467
llvm-svn: 286871
The functions getBitcodeTargetTriple(), isBitcodeContainingObjCCategory(),
getBitcodeProducerString() and hasGlobalValueSummary() now return errors
via their return value rather than via the diagnostic handler.
To make this work, re-implement these functions using non-member functions
so that they can be used without the LLVMContext required by BitcodeReader.
Differential Revision: https://reviews.llvm.org/D26532
llvm-svn: 286623
Summary:
Split ReaderWriter.h which contains the APIs into both the BitReader and
BitWriter libraries into BitcodeReader.h and BitcodeWriter.h.
This is to address Chandler's concern about sharing the same API header
between multiple libraries (BitReader and BitWriter). That concern is
why we create a single bitcode library in our downstream build of clang,
which led to r286297 being reverted as it added a dependency that
created a cycle only when there is a single bitcode library (not two as
in upstream).
Reviewers: mehdi_amini
Subscribers: dlj, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D26502
llvm-svn: 286566
This is forcing to use Error::success(), which is in a wide majority
of cases a lot more readable.
Differential Revision: https://reviews.llvm.org/D26481
llvm-svn: 286561
Unique ownership is just one possible ownership pattern for the memory buffer
underlying the bitcode reader. In practice, as this patch shows, ownership can
often reside at a higher level. With the upcoming change to allow multiple
modules in a single bitcode file, it will no longer be appropriate for
modules to generally have unique ownership of their memory buffer.
The C API exposes the ownership relation via the LLVMGetBitcodeModuleInContext
and LLVMGetBitcodeModuleInContext2 functions, so we still need some way for
the module to own the memory buffer. This patch does so by adding an owned
memory buffer field to Module, and using it in a few other places where it
is convenient.
Differential Revision: https://reviews.llvm.org/D26384
llvm-svn: 286214
Summary:
There is no point to importing at -O0, since we won't inline. We should
also disable other cross-module optimizations.
(Plan to backport this fix to the 3.9 branch to fix PR30774)
Reviewers: pcc
Subscribers: johanengelen, mehdi_amini
Differential Revision: https://reviews.llvm.org/D25918
llvm-svn: 285648
Summary:
When we have an aliasee that is linkonce, while we can't convert
the non-prevailing copies to available_externally, we still need to
convert the prevailing copy to weak. If a reference to the aliasee
is exported, not converting a copy to weak will result in undefined
references when the linkonce is removed in its original module.
Add a new test and update existing tests.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26076
llvm-svn: 285512
In an IR symbol table I would expect the comdats to be represented as:
- A table of strings, one for each comdat name.
- Each symbol has an optional index into that table.
The natural api for accessing that would be
InputFile:
ArrayRef<StringRef> getComdatTable() const;
Symbol:
int getComdatIndex() const;
This patch implements an API as close to that as possible. The
implementation on top of the current IRObjectFile is a bit hackish,
but should map just fine over a symbol table and is very convenient to
use.
llvm-svn: 285061
Summary:
This is a follow-up to D25416. It removes all usages of TimeValue from
llvm/Support library (except for the actual TimeValue declaration), and replaces
them with appropriate usages of std::chrono. To facilitate this, I have added
small utility functions for converting time points and durations into appropriate
OS-specific types (FILETIME, struct timespec, ...).
Reviewers: zturner, mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25730
llvm-svn: 284966
Summary:
Changes default backend parallelism from thread::hardware_concurrency to
the new llvm::heavyweight_hardware_concurrency, which for X86 Linux
defaults to the number of physical cores (and will fall back to
thread::hardware_concurrency otherwise). This avoid oversubscribing
the physical cores using hyperthreading.
Reviewers: mehdi_amini, pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25775
llvm-svn: 284618
Declare the LLVM_CMAKE_PATH to the source directory location of CMake
files, in order to make it possible to easily use them in subprojects.
Such a variable is already declared in most of LLVM projects
(and inconsistently mixed with direct source tree references), including
Clang, LLDB, compiler-rt, libcxx... Declaring it inside main LLVM tree
makes it possible to avoid having to declare fallback values or use
conditionals in those projects.
It should be noted that in some of the subprojects LLVM_CMAKE_PATH is
used to reference generated LLVMConfig.cmake file. However, these
references are conditional to stand-alone builds and explicitly
including this file is unnecessary in combined builds.
Differential Revision: https://reviews.llvm.org/D25724
llvm-svn: 284581
We need to use the overload of Mangler::getNameWithPrefix that takes a
GlobalValue in order to mangle in the stdcall stack byte count for Windows
targets.
Differential Revision: https://reviews.llvm.org/D25529
llvm-svn: 284040
Module inline asm was always being linked/concatenated
when running the IRLinker. This is correct for full LTO but not when
we are importing for ThinLTO, as it can result in multiply defined
symbols when the module asm defines a global symbol.
In order to test with llvm-lto2, I had to work around PR30396,
where a symbol that is defined in module assembly but defined in the
LLVM IR appears twice. Added workaround to llvm-lto2 with a FIXME.
Fixes PR30610.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25359
llvm-svn: 284030
Clang always emit a hash for ThinLTO, but as other frontend are
starting to use ThinLTO, this could be a serious bug.
Differential Revision: https://reviews.llvm.org/D25379
llvm-svn: 283655
We need to add an entry in the combined-index for modules that have
a hash but otherwise empty summary, this is needed so that we can
get the hash for the module.
Also, if no entry is present in the combined index for a module, we
need to skip it when trying to compute a cache entry.
Differential Revision: https://reviews.llvm.org/D25300
llvm-svn: 283654
Summary:
This patch improves thinlto importer
by importing 3x larger functions that are called from hot block.
I compared performance with the trunk on spec, and there
were about 2% on povray and 3.33% on milc. These results seems
to be consistant and match the results Teresa got with her simple
heuristic. Some benchmarks got slower but I think they are just
noisy (mcf, xalancbmki, omnetpp)- running the benchmarks again with
more iterations to confirm. Geomean of all benchmarks including the noisy ones
were about +0.02%.
I see much better improvement on google branch with Easwaran patch
for pgo callsite inlining (the inliner actually inline those big functions)
Over all I see +0.5% improvement, and I get +8.65% on povray.
So I guess we will see much bigger change when Easwaran patch will land
(it depends on new pass manager), but it is still worth putting this to trunk
before it.
Implementation details changes:
- Removed CallsiteCount.
- ProfileCount got replaced by Hotness
- hot-import-multiplier is set to 3.0 for now,
didn't have time to tune it up, but I see that we get most of the interesting
functions with 3, so there is no much performance difference with higher, and
binary size doesn't grow as much as with 10.0.
Reviewers: eraman, mehdi_amini, tejohnson
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24638
llvm-svn: 282437
The NativeObjectOutput class has a design problem: it mixes up the caching
policy with the interface for output streams, which makes the client-side
code hard to follow and would for example make it harder to replace the
cache implementation in an arbitrary client.
This change separates the two aspects by moving the caching policy
to a separate field in Config, replacing NativeObjectOutput with a
NativeObjectStream class which only deals with streams and does not need to
be overridden by most clients and introducing an AddFile callback for adding
files (e.g. from the cache) to the link.
Differential Revision: https://reviews.llvm.org/D24622
llvm-svn: 282299
With the new LTO API in r278338, we stopped emitting the individual
index files and imports files for some modules in the distributed backend
case (thinlto-index-only plugin option).
Specifically, this is when the linker decides not to include a module in the
link, because it was in an archive library and did not have a strong
reference to it. Not creating the expected output files makes the
distributed build system implementation more difficult, in terms of
checking for the expected outputs of the thin link, and scheduling the
backend jobs. To address this, the gold-plugin will write dummy empty
.thinlto.bc and .imports files for modules not included in the link
(which LTO never sees).
Augmented a gold v1.12+ test, since that version of gold has the handling
for notifying on modules not being included in the link.
llvm-svn: 282100
Summary:
Emit an empty summary section, instead of no summary section, when
there are no global variables in the index. This ensures that LTO
will treat these files as ThinLTO inputs, instead of as regular
LTO inputs.
In addition to not being what the user likely intended when
compiling with -flto=thin, the current behavior is problematic for
distributed build systems that expect to get ThinLTO index and imports
files back for each input compiled with -flto=thin. Combining into
a single regular LTO module also reduces the backend parallelism.
And in the case where the index was suppressed due to uses in
inline assembly, combining into a single LTO module could provoke
renaming of duplicates that we were trying to prevent by suppressing
the index.
This change required a couple of fixes to handle the empty summary
section.
Reviewers: mehdi_amini
Subscribers: mehdi_amini, llvm-commits, pcc
Differential Revision: https://reviews.llvm.org/D24779
llvm-svn: 282037
Summary:
In runThinLTO we start the task numbering for ThinLTO backend
tasks depending on whether there was also a regular LTO object
(CombinedModule). However, the CombinedModule is moved at
the end of runRegularLTO, so we need to save this information and
pass it into runThinLTO. Otherwise the AddOutput callback to the client
will use the same task number for both the regular LTO object
and the first ThinLTO object, which in gold-plugin caused only
one to be end up in the output filename array and therefore passed
back to gold for the final native link.
Reviewers: pcc, mehdi_amini
Subscribers: mehdi_amini, kromanova
Differential Revision: https://reviews.llvm.org/D24643
llvm-svn: 281725
Previously the prevailing information was not honored, and commons
symbols could override a strong definition. This patch fixes it and
propose the following semantic for commons: the client should mark
as prevailing the commons that it expects the LTO implementation to
merge (i.e. take the maximum size and alignment).
It implies that commons are allowed to have multiple prevailing
definitions.
Differential Revision: https://reviews.llvm.org/D24545
llvm-svn: 281538
Summary:
This addresses a regression in common handling from the new LTO
API in r278338. Only create a new common if the size is different.
The type comparison against an array type fails when the size is
different but not an array. GlobalMerge does not handle the
array types as well and we lose some global merging opportunities.
Reviewers: mehdi_amini
Subscribers: junbuml, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23955
llvm-svn: 279911
Summary:
Have the cache pass back the path to the cache entry when it
is ready to be loaded, instead of a buffer.
For gold-plugin we can simply pass this file back to gold directly,
which avoids expensive writing of a separate tmp file. Ensure
the cache entry is not deleted on cleanup by adjusting the setting
of the IsTemporary flags.
Moved the loading of the buffer into llvm-lto2 to maintain current
behavior.
Reviewers: mehdi_amini
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23946
llvm-svn: 279883
Add the ability to plug a cache on the LTO API.
I tried to write such that a linker implementation can
control the cache backend. This is intrusive and I'm
not totally happy with it, but I can't figure out a
better design right now.
Differential Revision: https://reviews.llvm.org/D23599
llvm-svn: 279576
Summary:
I assume there was a use case, so maybe this strawman patch will help
clarifying if it is legit.
In any case the current situation is not legit: a ThinLTO compilation
should not trigger an unexpected full LTO compilation.
Right now, adding a --save-temps option triggers this and makes the
number of output differs.
Reviewers: tejohnson
Subscribers: pcc, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23600
llvm-svn: 279550
An important performance setting on the LLVMContext for LTO is
enableDebugTypeODRUniquing(), this adds an automatic merging of
debug information in the context based on type ids.
Also, the lto::Config includes a diagnostic handler that needs to
be set on the Context, as well as the setDiscardValueNames() setting.
llvm-svn: 279532
It use to be non-const for the sole purpose of custom handling of
commons symbol. This is moved now in the regular LTO handling now
and such we can constify the callback.
llvm-svn: 279438
The gold-plugin was doing this internally, now the API is handling
commons correctly based on the given resolution.
Differential Revision: https://reviews.llvm.org/D23739
llvm-svn: 279417
directly produce the index as the value type result.
This requires making the index movable which is straightforward. It
greatly simplifies things by allowing us to completely avoid the builder
API and the layers of abstraction inherent there. Instead both pass
managers can directly construct these when run by value. They still
won't be constructed truly eagerly thanks to the optional in the legacy
PM. The code that directly builds the index can also just share a direct
function.
A notable change here is that the result type of the analysis for the
new PM is no longer a reference type. This was really problematic when
making changes to how we handle result types to make our interface
requirements *much* more strict and precise. But I think this is an
overall improvement.
Differential Revision: https://reviews.llvm.org/D23701
llvm-svn: 279216
Summary:
This was reversed compared to ThinLTOCodeGenerator for some reason,
and lead to an increased code-size on my tests. I figured that the
weak resolution may internalize a linkonce function, which will be
promoted immediately (and renamed), before being internalized again.
Reviewers: tejohnson
Subscribers: pcc, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23632
llvm-svn: 279021
Summary:
It does not play well with directories (end up with a bunch of hidden
files).
Also, do not strip the 0 suffix for the first task, especially since
0 can be used by ThinLTO as well now.
Reviewers: tejohnson
Subscribers: mehdi_amini, pcc, llvm-commits
Differential Revision: https://reviews.llvm.org/D23612
llvm-svn: 279014
Summary:
While NFC for now, this will allow more flexibility on the client side
to hold state necessary to back up the stream.
Also when adding caching, this class will grow in complexity.
Note I blindly modified the gold-plugin as I can't compile it.
Reviewers: tejohnson
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D23542
llvm-svn: 278907
Summary:
Multiple APIs were taking a StringMap for the ImportLists containing
the entries for for all the modules while operating on a single entry
for the current module. Instead we can pass the desired ModuleImport
directly. Also some of the APIs were not const, I believe just to be
able to use operator[] on the StringMap.
Reviewers: tejohnson
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23537
llvm-svn: 278776
Summary:
Fixed a bug in ThinLTOCodeGenerator's temp file dumping. The Twine
needs to be passed directly as an argument, or a copy saved into a
std::string.
It doesn't seem there are any consumers of this, so I added a new option
to llvm-lto to enable saving of temp files during ThinLTO, and augmented
a test to use it to check post-import but pre-opt bitcode.
Reviewers: mehdi_amini
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23525
llvm-svn: 278761
This restores commit r278330, with fixes for a few bot failures:
- Fix a late change I had made to the save temps output file that I
missed due to existing files sitting on my disk
- Fix a bunch of Windows bot failures with "ambiguous call to overloaded
function" due to confusion between llvm::make_unique vs
std::make_unique (preface the new make_unique calls with "llvm::")
- Attempt to fix a modules bot failure by adding a missing include
to LTO/Config.h.
Original change:
Resolution-based LTO API.
Summary:
This introduces a resolution-based LTO API. The main advantage of this API over
existing APIs is that it allows the linker to supply a resolution for each
symbol in each object, rather than the combined object as a whole. This will
become increasingly important for use cases such as ThinLTO which require us
to process symbol resolutions in a more complicated way than just adjusting
linkage.
Patch by Peter Collingbourne.
Reviewers: rafael, tejohnson, mehdi_amini
Subscribers: lhames, tejohnson, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D20268
llvm-svn: 278338
Mehdi Amini