The summary information includes all uses of llvm.type.test and
llvm.type.checked.load intrinsics that can be used to devirtualize calls,
including any constant arguments for virtual constant propagation.
Differential Revision: https://reviews.llvm.org/D29734
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294795 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r293970.
After more discussion, this belongs to the linker side and
there is no added value to do it at this level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293993 91177308-0d34-0410-b5e6-96231b3b80d8
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.
This is a recommit of r293912 after fixing build failures,
and a recommit of r293918 after fixing LLD tests.
Differential Revision: https://reviews.llvm.org/D28978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293970 91177308-0d34-0410-b5e6-96231b3b80d8
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.
This is a recommit of r293912 after fixing build failures.
Differential Revision: https://reviews.llvm.org/D28978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293918 91177308-0d34-0410-b5e6-96231b3b80d8
When a symbol is not exported outside of the
DSO, it is can be hidden. Usually we try to internalize
as much as possible, but it is not always possible, for
instance a symbol can be referenced outside of the LTO
unit, or there can be cross-module reference in ThinLTO.
Differential Revision: https://reviews.llvm.org/D28978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293912 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291177 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This adds a new summary flag NotEligibleToImport that subsumes
several existing flags (NoRename, HasInlineAsmMaybeReferencingInternal
and IsNotViableToInline). It also subsumes the checking of references
on the summary that was being done during the thin link by
eligibleForImport() for each candidate. It is much more efficient to
do that checking once during the per-module summary build and record
it in the summary.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28169
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291108 91177308-0d34-0410-b5e6-96231b3b80d8
If this is a problem for anyone (shared_ptr is two pointers in size,
whereas IntrusiveRefCntPtr is 1 - and the ref count control block that
make_shared adds is probably larger than the one int in RefCountedBase)
I'd prefer to address this by adding a lower-overhead version of
shared_ptr (possibly refactoring IntrusiveRefCntPtr into such a thing)
to avoid the intrusiveness - this allows memory ownership to remain
orthogonal to types and at least to me, seems to make code easier to
understand (since no implicit ownership acquisition can happen).
This recommits 291006, reverted in r291007.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291016 91177308-0d34-0410-b5e6-96231b3b80d8
Breaks Clang's use of bitcode. Reverting until I have a fix to go with
it there.
This reverts commit r291006.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291007 91177308-0d34-0410-b5e6-96231b3b80d8
If this is a problem for anyone (shared_ptr is two pointers in size,
whereas IntrusiveRefCntPtr is 1 - and the ref count control block that
make_shared adds is probably larger than the one int in RefCountedBase)
I'd prefer to address this by adding a lower-overhead version of
shared_ptr (possibly refactoring IntrusiveRefCntPtr into such a thing)
to avoid the intrusiveness - this allows memory ownership to remain
orthogonal to types and at least to me, seems to make code easier to
understand (since no implicit ownership acquisition can happen).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291006 91177308-0d34-0410-b5e6-96231b3b80d8
The Bitstream reader and writer are limited to handle a "size_t" at
most, which means that we can't backpatch and read back a 64bits
value on 32 bits platform.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290693 91177308-0d34-0410-b5e6-96231b3b80d8
This index record the position for each metadata record in
the bitcode, so that the reader will be able to lazy-load
on demand each individual record.
We also make sure that every abbrev is emitted upfront so
that the block can be skipped while reading.
I don't plan to commit this before having the reader
counterpart, but I figured this can be reviewed mostly
independently.
Recommit r290684 (was reverted in r290686 because a test
was broken) after adding a threshold to avoid emitting
the index when unnecessary (little amount of metadata).
This optimization "hides" a limitation of the ability
to backpatch in the bitstream: we can only backpatch
safely when the position has been flushed. So if we emit
an index for one metadata, it is possible that (part of)
the offset placeholder hasn't been flushed and the backpatch
will fail.
Differential Revision: https://reviews.llvm.org/D28083
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290690 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit a0ca6ae2d38339e4ede0dfa588086fc23d87e836. Revert at
Mehdi's request as it is breaking bots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290686 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This index record the position for each metadata record in
the bitcode, so that the reader will be able to lazy-load
on demand each individual record.
We also make sure that every abbrev is emitted upfront so
that the block can be skipped while reading.
I don't plan to commit this before having the reader
counterpart, but I figured this can be reviewed mostly
independently.
Reviewers: pcc, tejohnson
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28083
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290684 91177308-0d34-0410-b5e6-96231b3b80d8
Each function summary has an attached list of type identifier GUIDs. The
idea is that during the regular LTO phase we would match these GUIDs to type
identifiers defined by the regular LTO module and store the resolutions in
a top-level "type identifier summary" (which will be implemented separately).
Differential Revision: https://reviews.llvm.org/D27967
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290280 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades and a change
to the Bitcode record for DIGlobalVariable, that makes upgrading the
old format unambiguous also for variables without DIExpressions.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290153 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).
Sorry for the churn!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289982 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289920 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289902 91177308-0d34-0410-b5e6-96231b3b80d8
so we can stop using DW_OP_bit_piece with the wrong semantics.
The entire back story can be found here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161114/405934.html
The gist is that in LLVM we've been misinterpreting DW_OP_bit_piece's
offset field to mean the offset into the source variable rather than
the offset into the location at the top the DWARF expression stack. In
order to be able to fix this in a subsequent patch, this patch
introduces a dedicated DW_OP_LLVM_fragment operation with the
semantics that we used to apply to DW_OP_bit_piece, which is what we
actually need while inside of LLVM. This patch is complete with a
bitcode upgrade for expressions using the old format. It does not yet
fix the DWARF backend to use DW_OP_bit_piece correctly.
Implementation note: We discussed several options for implementing
this, including reserving a dedicated field in DIExpression for the
fragment size and offset, but using an custom operator at the end of
the expression works just fine and is more efficient because we then
only pay for it when we need it.
Differential Revision: https://reviews.llvm.org/D27361
rdar://problem/29335809
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288683 91177308-0d34-0410-b5e6-96231b3b80d8
This interface allows clients to write multiple modules to a single
bitcode file. Also introduce the llvm-cat utility which can be used
to create a bitcode file containing multiple modules.
Differential Revision: https://reviews.llvm.org/D26179
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288195 91177308-0d34-0410-b5e6-96231b3b80d8
This restores the rest of r286297 (part was restored in r286475).
Specifically, it restores the part requiring adding a dependency from
the Analysis to Object library (downstream use changed to correctly
model split BitReader vs BitWriter libraries).
Original description of this part of patch follows:
Module level asm may also contain defs of values. We need to prevent
export of any refs to local values defined in module level asm (e.g. a
ref in normal IR), since that also requires renaming/promotion of the
local. To do that, the summary index builder looks at all values in the
module level asm string that are not marked Weak or Global, which is
exactly the set of locals that are defined. A summary is created for
each of these local defs and flagged as NoRename.
This required adding handling to the BitcodeWriter to look at GV
declarations to see if they have a summary (rather than skipping them
all).
Finally, added an assert to IRObjectFile::CollectAsmUndefinedRefs to
ensure that an MCAsmParser is available, otherwise the module asm parse
would silently fail. Initialized the asm parser in the opt tool for use
in testing this fix.
Fixes PR30610.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286844 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The change in r285513 to prevent exporting of locals used in
inline asm added all locals in the llvm.used set to the reference
set of functions containing inline asm. Since these locals were marked
NoRename, this automatically prevented importing of the function.
Unfortunately, this caused an explosion in the summary reference lists
in some cases. In my particular example, it happened for a large protocol
buffer generated C++ file, where many of the generated functions
contained an inline asm call. It was exacerbated when doing a ThinLTO
PGO instrumentation build, where the PGO instrumentation included
thousands of private __profd_* values that were added to llvm.used.
We really only need to include a single llvm.used local (NoRename) value
in the reference list of a function containing inline asm to block it
being imported. However, it seems cleaner to add a flag to the summary
that explicitly describes this situation, which is what this patch does.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26402
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286840 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286566 91177308-0d34-0410-b5e6-96231b3b80d8
If the inrange keyword is present before any index, loading from or
storing to any pointer derived from the getelementptr has undefined
behavior if the load or store would access memory outside of the bounds of
the element selected by the index marked as inrange.
This can be used, e.g. for alias analysis or to split globals at element
boundaries where beneficial.
As previously proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-July/102472.html
Differential Revision: https://reviews.llvm.org/D22793
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286514 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r286297.
Introduces a dependency from libAnalysis to libObject, which I missed
during the review.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286329 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch uses the same approach added for inline asm in r285513 to
similarly prevent promotion/renaming of locals used or defined in module
level asm.
All static global values defined in normal IR and used in module level asm
should be included on either the llvm.used or llvm.compiler.used global.
The former were already being flagged as NoRename in the summary, and
I've simply added llvm.compiler.used values to this handling.
Module level asm may also contain defs of values. We need to prevent
export of any refs to local values defined in module level asm (e.g. a
ref in normal IR), since that also requires renaming/promotion of the
local. To do that, the summary index builder looks at all values in the
module level asm string that are not marked Weak or Global, which is
exactly the set of locals that are defined. A summary is created for
each of these local defs and flagged as NoRename.
This required adding handling to the BitcodeWriter to look at GV
declarations to see if they have a summary (rather than skipping them
all).
Finally, added an assert to IRObjectFile::CollectAsmUndefinedRefs to
ensure that an MCAsmParser is available, otherwise the module asm parse
would silently fail. Initialized the asm parser in the opt tool for use
in testing this fix.
Fixes PR30610.
Reviewers: mehdi_amini
Subscribers: johanengelen, krasin, llvm-commits
Differential Revision: https://reviews.llvm.org/D26146
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286297 91177308-0d34-0410-b5e6-96231b3b80d8
We already read the flags out of the summary when writing the summary
records for functions and aliases, do the same for variables.
This is an NFC change for now since the flags computed on the fly from
the GlobalValue currently will always match those in the summary
already, but once I send a follow-on patch to set the NoRename flag for
locals in the llvm.used set this becomes a necessary change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285433 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Previously we were creating the alias summary on the fly while writing
the summary to bitcode. This moves the creation of these summaries to
the module summary index builder where we build the rest of the summary
index.
This is going to be necessary for setting the NoRename flag for values
possibly used in inline asm or module level asm.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26049
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285379 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is in preparation for a change to utilize this flag for symbols
referenced/defined in either inline or module level assembly.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26048
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285376 91177308-0d34-0410-b5e6-96231b3b80d8
- Add alignment attribute to DIVariable family
- Modify bitcode format to match new DIVariable representation
- Update tests to match these changes (also add bitcode upgrade test)
- Expect that frontend passes non-zero align value only when it is not default
(was forcibly aligned by alignas()/_Alignas()/__atribute__(aligned())
Differential Revision: https://reviews.llvm.org/D25073
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284678 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282437 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282037 91177308-0d34-0410-b5e6-96231b3b80d8
The ValueSymbolTable is used to detect name conflict and rename
instructions automatically. This is not needed when the value
names are automatically discarded by the LLVMContext.
No functional change intended, just saving a little bit of memory.
This is a recommit of r281806 after fixing the accessor to return
a pointer instead of a reference and updating all the call-sites.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281813 91177308-0d34-0410-b5e6-96231b3b80d8
This patch reverses the edge from DIGlobalVariable to GlobalVariable.
This will allow us to more easily preserve debug info metadata when
manipulating global variables.
Fixes PR30362. A program for upgrading test cases is attached to that
bug.
Differential Revision: http://reviews.llvm.org/D20147
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281284 91177308-0d34-0410-b5e6-96231b3b80d8
In cases where .dwo/.dwp files are guaranteed to be available, skipping
the extra online (in the .o file) inline info can save a substantial
amount of space - see the original r221306 for more details there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279650 91177308-0d34-0410-b5e6-96231b3b80d8
