While testing a follow-on change to enable index-based symbol resolution
and internalization in the distributed backends, I realized that a test
case change I made in r275247 was only required because we were not
analyzing symbols in the claimed files in thinlto-index-only mode.
In the fixed test case there should be no internalization because we are
linking in -shared mode, so f() is in fact exported, which is detected
properly when we analyze symbols in thinlto-index-only mode. Note that
this is not (yet) a correctness issue (because we are not yet performing
the index-based linkage optimizations in the distributed backends -
that's coming in a follow-on patch).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275277 91177308-0d34-0410-b5e6-96231b3b80d8
Internalization was missing cases where we originally had a local symbol
that was promoted eagerly but not actually exported. This is because we
were only internalizing the set of global (non-local) symbols that were
PREVAILAING_DEF_IRONLY. Instead, collect the set of global symbols that
are referenced outside of a single IR file, and skip internalization for
those.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275247 91177308-0d34-0410-b5e6-96231b3b80d8
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272709 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Several changes were required for ThinLTO links involving bitcode
archive static libraries. With this patch clang/llvm bootstraps with
ThinLTO and gold.
The first is that the gold callbacks get_input_file and
release_input_file can normally be used to get file information for
each constituent bitcode file within an archive. However, these
interfaces lock the underlying file and can't be for each archive
constituent for ThinLTO backends where we get all the input files up
front and don't release any until after the backend threads complete.
However, it is sufficient to only get and release once per file, and
then each consituent bitcode file can be accessed via get_view. This
required saving some information to identify which file handle is the
"leader" for each claimed file sharing the same file descriptor, and
other information so that get_input_file isn't necessary later when
processing the backends.
Second, the module paths in the index need to distinguish between
different constituent bitcode files within the same archive file,
otherwise they will all end up with the same archive file path.
Do this by appending the offset within the archive for the start of the
bitcode file, returned by get_input_file when we claim each bitcode file,
and saving that along with the file handle.
Third, rather than have the function importer try to load a file based
on the module path identifier (which now contains a suffix to
distinguish different bitcode files within an archive), use a custom
module loader. This is the same approach taken in libLTO, and I am using
the support refactored into the new LTO.h header in r270509. The module
loader parses the bitcode files out of the memory buffers returned from
gold via the get_view callback and saved in a map. This also means that
we call the function importer directly, rather than add it to the pass
pipeline (which was in the plan to do already for other reasons).
Reviewers: pcc, joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D20559
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270814 91177308-0d34-0410-b5e6-96231b3b80d8
Having an enum member named Default is quite confusing: Is it distinct
from the others?
This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269988 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Colons can appear in Windows paths after drive letters. Both colon and
semicolon are valid characters in filenames, but neither are very
common. Semicolon seems just as good, and makes the test pass on
Windows.
Reviewers: tejohnson
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D20332
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269798 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add support to control where files for a distributed backend (the
individual index files and optional imports files) are created.
This is invoked with a new thinlto-prefix-replace option in the gold
plugin and llvm-lto. If specified, expects a string of the form
"oldprefix:newprefix", and instead of generating these files in the
same directory path as the corresponding bitcode file, will use a path
formed by replacing the bitcode file's path prefix matching oldprefix
with newprefix.
Also add a new replace_path_prefix helper to Path.h in libSupport.
Depends on D19636.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D19644
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269771 91177308-0d34-0410-b5e6-96231b3b80d8
This change is the gold side of the change made in D17115 and clang
patch r261045 to add a ThinLTO specific pipeline that moves more of
the optimization to the backends.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269386 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add support for emission of plaintext lists of the imported files for
each distributed backend compilation. Used for distributed build file
staging.
Invoked with new gold-plugin thinlto-emit-imports-files option, which is
only valid with thinlto-index-only (i.e. for distributed builds), or
from llvm-lto with new -thinlto-action=emitimports value.
Depends on D19556.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D19636
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This restores commit r268627:
Summary:
When launching ThinLTO backends in a distributed build (currently
supported in gold via the thinlto-index-only plugin option), emit
an individual index file for each backend process as described here:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098272.html
...
Differential Revision: http://reviews.llvm.org/D19556
Address msan failures by avoiding std::prev on map.end(), the
theory is that this is causing issues due to some known UB problems
in __tree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269059 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When launching ThinLTO backends in a distributed build (currently
supported in gold via the thinlto-index-only plugin option), emit
an individual index file for each backend process as described here:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098272.html
The individual index file encodes the summary and module information
required for implementing the importing/exporting decisions made
for a given module in the thin link step.
This is in place of the current mechanism that uses the combined index
to make importing decisions in each back end independently. It is an
enabler for doing global summary based optimizations in the thin link
step (which will be recorded in the individual index files), and reduces
the size of the index that must be sent to each backend process, and
the amount of work to scan it in the backends.
Rather than create entirely new ModuleSummaryIndex structures (and all
the included unique_ptrs) for each backend index file, a map is created
to record all of the GUID and summary pointers needed for a particular
index file. The IndexBitcodeWriter walks this map instead of the full
index (hiding the details of managing the appropriate summary iteration
in a new iterator subclass). This is more efficient than walking the
entire combined index and filtering out just the needed summaries during
each backend bitcode index write.
Depends on D19481.
Reviewers: joker.eph
Subscribers: llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D19556
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268627 91177308-0d34-0410-b5e6-96231b3b80d8
Fix early exit from linkInModule. IRMover::move returns false on
success and true on error.
Add a few more cases of merged common linkage variables with
different sizes and alignments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267437 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This removes a couple of flags added to control this behavior, and
simply keeps all value names when save-temps is specified.
Reviewers: rafael
Subscribers: llvm-commits, pcc, davide
Differential Revision: http://reviews.llvm.org/D19384
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267279 91177308-0d34-0410-b5e6-96231b3b80d8
This restores r266871 with a fix for gold tests relying on the value
names, when using a release compiler, by adding a way to disable the
default discarding. Update affected tests to use the new mechanism so
that value names are preserved as expected, regardless of how the
compiler was built.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266881 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch prevents importing from (and therefore exporting from) any
module with a "llvm.used" local value. Local values need to be promoted
and renamed when importing, and their presense on the llvm.used variable
indicates that there are opaque uses that won't see the rename. One such
example is a use in inline assembly.
See also the discussion at:
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098047.html
As part of this, move collectUsedGlobalVariables out of Transforms/Utils
and into IR/Module so that it can be used more widely. There are several
other places in LLVM that used copies of this code that can be cleaned
up as a follow on NFC patch.
Reviewers: joker.eph
Subscribers: pcc, llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D18986
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266877 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r266871. Setting the default based on the NDEBUG
flag is causing test failures. Need to figure out whether to change this
approach or update tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266872 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Applies Mehdi's optimization (r263086) to disable value names other than
for GlobalValues to LTO/ThinLTO performed via the gold-plugin, in the
same manner as it is applied in libLTO.
Reviewers: rafael, joker-eph
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19269
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266871 91177308-0d34-0410-b5e6-96231b3b80d8
As per David's review, rename everything in the new API for ODR type
uniquing of debug info.
ensureDITypeMap => enableDebugTypeODRUniquing
destroyDITypeMap => disableDebugTypeODRUniquing
hasDITypeMap => isODRUniquingDebugTypes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266713 91177308-0d34-0410-b5e6-96231b3b80d8
Rather than relying on the structural equivalence of DICompositeType to
merge type definitions, use an explicit map on the LLVMContext that
LLParser and BitcodeReader consult when constructing new nodes.
Each non-forward-declaration DICompositeType with a non-empty
'identifier:' field is stored/loaded from the type map, and the first
definiton will "win".
This map is opt-in: clients that expect ODR types from different modules
to be merged must call LLVMContext::ensureDITypeMap.
- Clients that just happen to load more than one Module in the same
LLVMContext won't magically merge types.
- Clients (like LTO) that want to continue to merge types based on ODR
identifiers should opt-in immediately.
I have updated LTOCodeGenerator.cpp, the two "linking" spots in
gold-plugin.cpp, and llvm-link (unless -disable-debug-info-type-map) to
set this.
With this in place, it will be straightforward to remove the DITypeRef
concept (i.e., referencing types by their 'identifier:' string rather
than pointing at them directly).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266549 91177308-0d34-0410-b5e6-96231b3b80d8
(Resubmitting after fixing missing file issue)
With the changes in r263275, there are now more than just functions in
the summary. Completed the renaming of data structures (started in
r263275) to reflect the wider scope. In particular, changed the
FunctionIndex* data structures to ModuleIndex*, and renamed related
variables and comments. Also renamed the files to reflect the changes.
A companion clang patch will immediately succeed this patch to reflect
this renaming.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263513 91177308-0d34-0410-b5e6-96231b3b80d8
With the changes in r263275, there are now more than just functions in
the summary. Completed the renaming of data structures (started in
r263275) to reflect the wider scope. In particular, changed the
FunctionIndex* data structures to ModuleIndex*, and renamed related
variables and comments. Also renamed the files to reflect the changes.
A companion clang patch will immediately succeed this patch to reflect
this renaming.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263490 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch adds support for including a full reference graph including
call graph edges and other GV references in the summary.
The reference graph edges can be used to make importing decisions
without materializing any source modules, can be used in the plugin
to make file staging decisions for distributed build systems, and is
expected to have other uses.
The call graph edges are recorded in each function summary in the
bitcode via a list of <CalleeValueIds, StaticCount> tuples when no PGO
data exists, or <CalleeValueId, StaticCount, ProfileCount> pairs when
there is PGO, where the ValueId can be mapped to the function GUID via
the ValueSymbolTable. In the function index in memory, the call graph
edges reference the target via the CalleeGUID instead of the
CalleeValueId.
The reference graph edges are recorded in each summary record with a
list of referenced value IDs, which can be mapped to value GUID via the
ValueSymbolTable.
Addtionally, a new summary record type is added to record references
from global variable initializers. A number of bitcode records and data
structures have been renamed to reflect the newly expanded scope of the
summary beyond functions. More cleanup will follow.
Reviewers: joker.eph, davidxl
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D17212
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263275 91177308-0d34-0410-b5e6-96231b3b80d8
LLVM Gold plugin decides which instance of a common symbol it wants
based on the symbol size in claim_file_hook. If the file that
contains the chosen instance is later dropped from the link, we end
up with an undefined reference.
This change delays this decision until the set of the included files
is known.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263180 91177308-0d34-0410-b5e6-96231b3b80d8
The split code gen task ID should not be appended to save-temps output
file when the parallelism factor is 1 (not actually splitting).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262731 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Since IR files are all compiled into separate independent object files
in ThinLTO mode, the prevailing linkonce symbols must be emitted in its
object file even if it is no longer referenced there, e.g. if no
references remain in the module after inlining, since it may be
referenced by another ThinLTO compiled object file. This is done by
changing LDPR_PREVAILING_DEF_IRONLY* symbols to LDPR_PREVAILING_DEF,
which converts the prevailing linkonce to weak. We also don't need the
other prevailing IRONLY handling for internalization, which is not
currently performed for ThinLTO.
Test case included.
Reviewers: davidxl, rafael
Subscribers: rafael, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D16173
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262727 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Launch ThinLTO backends (LTO and codegen pipelines with importing) in
parallel using a ThreadPool, after creating the combined index.
The number of threads is controlled by the existing -jobs gold plugin
option, or the hardware concurrency if not specified.
The old behavior of exiting after creating the combined index can be
invoked via a new thinlto-index-only plugin option.
This commit involves just the ThinLTO-specific pieces of D15390, the NFC
and other restructuring pieces were committed independently:
r262677: Add hardware_concurrency interface to llvm::thread (NFC)
r262719: Change split code gen to use ThreadPool
r262721: Refactor gold-plugin codegen to prepare for ThinLTO threads (NFC)
Reviewers: pcc, joker.eph, rafael
Subscribers: rafael, davidxl, llvm-commits, joker.eph
Differential Revision: http://reviews.llvm.org/D15390
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262724 91177308-0d34-0410-b5e6-96231b3b80d8
This is the NFC part remaining from D15390, which refactors the
current codegen() into a CodeGen class with various modular methods and
other helper functions that will be used by the follow-on ThinLTO piece.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262721 91177308-0d34-0410-b5e6-96231b3b80d8
Gold has a newly added LDPT_GET_SYMBOLS_V3 callback that can
distinguish between a module that is not included in the link, and
one that is included but has its entire interface preempted by others.
Fixes PR26674.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262676 91177308-0d34-0410-b5e6-96231b3b80d8
It turns out that his is *really* slow. With this change the link of
clang with plugin-opt=emit-llvm goes from 41 to 26 seconds.
We can add an option to enable it again if needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256302 91177308-0d34-0410-b5e6-96231b3b80d8
