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Commit Graph

326 Commits

Author SHA1 Message Date
Teresa Johnson
69629c2314 [PM] Port NameAnonFunction pass to new pass manager
Summary:
Port the NameAnonFunction pass and add a test.

Depends on D23439.

Reviewers: mehdi_amini

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23440

llvm-svn: 278509
2016-08-12 14:03:36 +00:00
Teresa Johnson
3e48c70c20 [PM] Port ModuleSummaryIndex analysis to new pass manager
Summary:
Port the ModuleSummaryAnalysisWrapperPass to the new pass manager.
Use it in the ported BitcodeWriterPass (similar to how we use the
legacy ModuleSummaryAnalysisWrapperPass in the legacy WriteBitcodePass).

Also, pass the -module-summary opt flag through to the new pass
manager pipeline and through to the bitcode writer pass, and add
a test that uses it.

Reviewers: mehdi_amini

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23439

llvm-svn: 278508
2016-08-12 13:53:02 +00:00
Piotr Padlewski
2ede910872 Don't import variadic functions
Summary:
This patch adds IsVariadicFunction bit to summary in order
to not import variadic functions. Inliner doesn't inline
variadic functions because it is hard to reason about it.

This one small fix improves Importer by about 16%
(going from 86% to 100% of imported functions that are
inlined anywhere)
on some spec benchmarks like 'int' and others.

Reviewers: eraman, mehdi_amini, tejohnson

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D23339

llvm-svn: 278432
2016-08-11 22:13:57 +00:00
Nicolai Haehnle
fe1657d8ae Add writeonly IR attribute
Summary:
This complements the earlier addition of IntrWriteMem and IntrWriteArgMem
LLVM intrinsic properties, see D18291.

Also start using the attribute for memset, memcpy, and memmove intrinsics,
and remove their special-casing in BasicAliasAnalysis.

Reviewers: reames, joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D18714

llvm-svn: 274485
2016-07-04 08:01:29 +00:00
Reid Kleckner
f448343ea4 [codeview] Add DISubprogram::ThisAdjustment
Summary:
This represents the adjustment applied to the implicit 'this' parameter
in the prologue of a virtual method in the MS C++ ABI. The adjustment is
always zero unless multiple inheritance is involved.

This increases the size of DISubprogram by 8 bytes, unfortunately. The
adjustment really is a signed 32-bit integer. If this size increase is
too much, we could probably win it back by splitting out a subclass with
info specific to virtual methods (virtuality, vindex, thisadjustment,
containingType).

Reviewers: aprantl, dexonsmith

Subscribers: aaboud, amccarth, llvm-commits

Differential Revision: http://reviews.llvm.org/D21614

llvm-svn: 274325
2016-07-01 02:41:21 +00:00
Peter Collingbourne
f6bbbabcc3 BitcodeWriter: Remove redundant (and incorrect) check for whether to emit module summary.
The function name Module::empty() is slightly misleading in that it
only tests for the presence of functions in the module. However we
still want to emit the module summary if the module contains only
global variables or aliases. The presence of such entities can be
determined simply by checking the summary directly, as we are doing
below.

Differential Revision: http://reviews.llvm.org/D21669

llvm-svn: 273638
2016-06-24 01:58:02 +00:00
Peter Collingbourne
5dcb77e9fb IR: Introduce local_unnamed_addr attribute.
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.html
http://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

llvm-svn: 272709
2016-06-14 21:01:22 +00:00
Filipe Cabecinhas
929b72c699 [BitCode] Make sure atomicrmw's argument is an actual PointerType
llvm-svn: 271851
2016-06-05 18:43:40 +00:00
Filipe Cabecinhas
020e10c851 [BitCode] Make sure storeatomic's argument is an actual PointerType
llvm-svn: 271850
2016-06-05 18:43:33 +00:00
Filipe Cabecinhas
06c97ab46d [BitCode] Diagnose GEPs with no indices
llvm-svn: 271849
2016-06-05 18:43:26 +00:00
Filipe Cabecinhas
cb52965257 [BitCode] Don't allow constants of void type.
llvm-svn: 271848
2016-06-05 18:43:17 +00:00
Manman Ren
0877622c14 Objective-C Class Properties: Autoupgrade "Class Properties" module flag.
When we have "Image Info Version" module flag but don't have "Class Properties"
module flag, set "Class Properties" module flag to 0, so we can correctly emit
errors when one module has the flag set and another module does not.

rdar://26469641

llvm-svn: 270791
2016-05-25 23:14:48 +00:00
Nikolay Haustov
cc09085f4b AMDGPU/SI: Add amdgpu_kernel calling convention. Part 1.
Summary:
This will be used for AMDGPU_HSA_KERNEL symbol type in output ELF.

Also, in the future unused non-kernels may be optimized.

For now, also accept SPIR_KERNEL for HCC frontend.

Also, add bitcode compatibility tests for missing calling conventions
except AVR_BUILTIN which doesn't have parse code.

Reviewers: tstellarAMD, arsenm

Subscribers: arsenm, joker.eph, llvm-commits
llvm-svn: 268717
2016-05-06 09:07:29 +00:00
Teresa Johnson
1ec75cc513 [ThinLTO] Use valueid instead of bitcode offsets in combined index file
Summary:
With the removal of support for lazy parsing of combined index summary
records (e.g. r267344), we no longer need to include the summary record
bitcode offset in the VST entries for definitions. Change the combined
index format to be similar to the per-module index format in using value
ids to cross-reference from the summary record to the VST entry (rather
than the summary record bitcode offset to cross-reference in the other
direction).

The visible changes are:
1) Add the value id to the combined summary records
2) Remove the summary offset from the combined VST records, which has
the following effects:
- No longer need the VST_CODE_COMBINED_GVDEFENTRY record, as all
  combined index VST entries now only contain the value id and
  corresponding GUID.
- No longer have duplicate VST entries in the case where there are
  multiple definitions of a symbol (e.g. weak/linkonce), as they all
  have the same value id and GUID.

An implication of #2 above is that in order to hook up an alias to the
correct aliasee based on the value id of the aliasee recorded in the
combined index alias record, we need to scan the entries in the index
for that GUID to find the one from the same module (i.e. the case where
there are multiple entries for the aliasee). But the reader no longer
has to maintain a special map to hook up the alias/aliasee.

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D19481

llvm-svn: 267712
2016-04-27 13:28:35 +00:00
Sanjoy Das
938a0f7381 Symbolize operand bundle blocks for bcanalyzer
Reviewers: joker.eph

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19523

llvm-svn: 267524
2016-04-26 05:59:08 +00:00
Duncan P. N. Exon Smith
edafeb956c BitcodeReader: Fix some holes in upgrade from r267296
Add tests for some missing cases to bitcode upgrade in r267296.

  - DICompositeType with an 'elements:' field, which will cause it to be
    involved in a cycle after the upgrade.

  - A DIDerivedType that references a class in 'extraData:'.

I updated test/Bitcode/dityperefs-3.8.ll with the missing cases and
regenerated test/Bitcode/dityperefs-3.8.ll.bc.

llvm-svn: 267332
2016-04-24 06:52:01 +00:00
Mehdi Amini
ae8cf7ca98 Add "hasSection" flag in the Summary
Reviewers: tejohnson

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D19405

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267329
2016-04-24 05:31:43 +00:00
Mehdi Amini
9e35f9ec46 Reorganize GlobalValueSummary with a "Flags" bitfield.
Right now it only contains the LinkageType, but will be extended
with "hasSection", "isOptSize", "hasInlineAssembly", etc.

Differential Revision: http://reviews.llvm.org/D19404

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267319
2016-04-24 03:18:18 +00:00
Mehdi Amini
e000bb6ae8 Add a version field in the bitcode for the summary
Differential Revision: http://reviews.llvm.org/D19456

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267318
2016-04-24 03:18:11 +00:00
Mehdi Amini
deab28a4fa Relax test using CHECK-DAG instead of CHECK-NEXT
It seems we still have some ordering issue in the combined index
emission, but I can't figure out why right now.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267306
2016-04-24 00:25:15 +00:00
Mehdi Amini
9b7843d732 Fix test stability (was sensitive to the path)
This is a fixup for r267304.
The test was sensitive to the path in a subtle way:
the index in memory is sorted by GUID, which are hashes
that include the source filename for local globals.
Teresa recently added a directive at the IR level, so
we can specify it here to make the test independent of
the path.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267305
2016-04-24 00:03:57 +00:00
Mehdi Amini
87de206ac4 Store and emit original name in combined index
Summary:
As discussed in D18298, some local globals can't
be renamed/promoted (because they have a section, or because
they are referenced from inline assembly).
To be able to detect naming collision, we need to keep around
the "GUID" using their original name without taking the linkage
into account.

Reviewers: tejohnson

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D19454

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267304
2016-04-23 23:38:17 +00:00
Duncan P. N. Exon Smith
94512f24de DebugInfo: Remove MDString-based type references
Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*.  It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.

Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType.  The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.

This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata.  Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.

The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":

  http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html

llvm-svn: 267296
2016-04-23 21:08:00 +00:00
Duncan P. N. Exon Smith
5b72a15d9d BitcodeWriter: Emit uniqued subgraphs after all distinct nodes
Since forward references for uniqued node operands are expensive (and
those for distinct node operands are cheap due to
DistinctMDOperandPlaceholder), minimize forward references in uniqued
node operands.

Moreover, guarantee that when a cycle is broken by a distinct node, none
of the uniqued nodes have any forward references.  In
ValueEnumerator::EnumerateMetadata, enumerate uniqued node subgraphs
first, delaying distinct nodes until all uniqued nodes have been
handled.  This guarantees that uniqued nodes only have forward
references when there is a uniquing cycle (since r267276 changed
ValueEnumerator::organizeMetadata to partition distinct nodes in front
of uniqued nodes as a post-pass).

Note that a single uniqued subgraph can hit multiple distinct nodes at
its leaves.  Ideally these would themselves be emitted in post-order,
but this commit doesn't attempt that; I think it requires an extra pass
through the edges, which I'm not convinced is worth it (since
DistinctMDOperandPlaceholder makes forward references quite cheap
between distinct nodes).

I've added two testcases:

  - test/Bitcode/mdnodes-distinct-in-post-order.ll is just like
    test/Bitcode/mdnodes-in-post-order.ll, except with distinct nodes
    instead of uniqued ones.  This confirms that, in the absence of
    uniqued nodes, distinct nodes are still emitted in post-order.

  - test/Bitcode/mdnodes-distinct-nodes-break-cycles.ll is the minimal
    example where a naive post-order traversal would cause one uniqued
    node to forward-reference another.  IOW, it's the motivating test.

llvm-svn: 267278
2016-04-23 04:59:22 +00:00
Duncan P. N. Exon Smith
f5921278f9 BitcodeWriter: Emit distinct nodes before uniqued nodes
When an operand of a distinct node hasn't been read yet, the reader can
use a DistinctMDOperandPlaceholder.  This is much cheaper than forward
referencing from a uniqued node.  Change
ValueEnumerator::organizeMetadata to partition distinct nodes and
uniqued nodes to reduce the overhead of cycles broken by distinct nodes.

Mehdi measured this for me; this removes most of the RAUW from the
importing step of -flto=thin, even after a WIP patch that removes
string-based DITypeRefs (introducing many more cycles to the metadata
graph).

llvm-svn: 267276
2016-04-23 04:42:39 +00:00
Duncan P. N. Exon Smith
556324f139 BitcodeWriter: Emit metadata in post-order (again)
Emit metadata nodes in post-order.  The iterative algorithm from r266709
failed to maintain this property.  After understanding my mistake, it
wasn't too hard to write a test with llvm-bcanalyzer (and I've actually
made this change once before: see r220340).

This also reverts the "noisy" testcase change from r266709.  That should
have been more of a red flag :/.

Note: The same bug crept into the ValueMapper in r265456.  I'm still
working on the fix.

llvm-svn: 266947
2016-04-21 01:55:12 +00:00
Duncan P. N. Exon Smith
32da2f75ed BitcodeWriter: Break recursion when enumerating Metadata, almost NFC
Use a worklist instead of recursing through MDNode operands in
ValueEnumerator.  The actual record output order has changed slightly,
but otherwise there's no functionality change.

I had to update test/Bitcode/metadata-function-blocks.ll.  I renumbered
nodes so they continue to match the implicit record ids.

llvm-svn: 266709
2016-04-19 03:46:51 +00:00
Mehdi Amini
d3e6360b27 ThinLTO: Make aliases explicit in the summary
To be able to work accurately on the reference graph when taking
decision about internalizing, promoting, renaming, etc. We need
to have the alias information explicit.

Differential Revision: http://reviews.llvm.org/D18836

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266517
2016-04-16 06:56:44 +00:00
Adrian Prantl
fb3abba237 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

llvm-svn: 266446
2016-04-15 15:57:41 +00:00
Mehdi Amini
6968b7bc43 Revert "Make aliases explicit in the summary"
Inadvertently commited...

This reverts commit e618ec93786d99df2ddf280ad2d5e02f5516cecf.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266215
2016-04-13 17:20:07 +00:00
Mehdi Amini
d96d756a2f Make aliases explicit in the summary
Summary:
To be able to work accurately on the reference graph when taking decision
about internalizing, promoting, renaming, etc. We need to have the alias
information explicit.

Reviewers: tejohnson

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D18836

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266214
2016-04-13 17:18:42 +00:00
Mehdi Amini
03a2cdacee Move summary creation out of llvm-as into opt
Summary:
Let keep llvm-as "dumb": it converts textual IR to bitcode. This
commit removes the dependency from llvm-as to libLLVMAnalysis.
We'll add back summary in llvm-as if we get to a textual
representation for it at some point. In the meantime, opt seems
like a better place for that.

Reviewers: tejohnson

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D19032

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266131
2016-04-12 21:35:18 +00:00
Davide Italiano
e11049fef8 [Bitcode] Fix + regenerate old test so that it includes a DICompileUnit.
llvm-svn: 266085
2016-04-12 15:51:23 +00:00
George Burgess IV
4e2d8dca99 Add the allocsize attribute to LLVM.
`allocsize` is a function attribute that allows users to request that
LLVM treat arbitrary functions as allocation functions.

This patch makes LLVM accept the `allocsize` attribute, and makes
`@llvm.objectsize` recognize said attribute.

The review for this was split into two patches for ease of reviewing:
D18974 and D14933. As promised on the revisions, I'm landing both
patches as a single commit.

Differential Revision: http://reviews.llvm.org/D14933

llvm-svn: 266032
2016-04-12 01:05:35 +00:00
Teresa Johnson
d7c9485243 [ThinLTO] Move summary computation from BitcodeWriter to new pass
Summary:
This is the first step in also serializing the index out to LLVM
assembly.

The per-module summary written to bitcode is moved out of the bitcode
writer and to a new analysis pass (ModuleSummaryIndexWrapperPass).
The pass itself uses a new builder class to compute index, and the
builder class is used directly in places where we don't have a pass
manager (e.g. llvm-as).

Because we are computing summaries outside of the bitcode writer, we no
longer can use value ids created by the bitcode writer's
ValueEnumerator. This required changing the reference graph edge type
to use a new ValueInfo class holding a union between a GUID (combined
index) and Value* (permodule index). The Value* are converted to the
appropriate value ID during bitcode writing.

Also, this enables removal of the BitWriter library's dependence on the
Analysis library that was previously required for the summary computation.

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D18763

llvm-svn: 265941
2016-04-11 13:58:45 +00:00
Dmitry Polukhin
9d54726038 [GCC] Attribute ifunc support in llvm
This patch add support for GCC attribute((ifunc("resolver"))) for
targets that use ELF as object file format. In general ifunc is a
special kind of function alias with type @gnu_indirect_function. Patch
for Clang http://reviews.llvm.org/D15524

Differential Revision: http://reviews.llvm.org/D15525

llvm-svn: 265667
2016-04-07 12:32:19 +00:00
Duncan P. N. Exon Smith
56e0bfec77 Bitcode: Try to emit metadata in function blocks
Whenever metadata is only referenced by a single function, emit the
metadata just in that function block.  This should improve lazy-loading
by reducing the amount of metadata in the global block.

For now, this should catch all DILocations, and anything else that
happens to be referenced only by a single function.

It's also a first step toward a couple of possible future directions
(which this commit does *not* implement):

 1. Some debug info metadata is only referenced from compile units and
    individual functions.  If we can drop the link from the compile
    unit, this optimization will get more powerful.

 2. Any uniqued metadata that isn't referenced globally can in theory be
    emitted in every function block that references it (trading off
    bitcode size and full-parse time vs. lazy-load time).

Note: this assumes the new BitcodeReader error checking from r265223.
The metadata stored in function blocks gets purged after parsing each
function, which means unresolved forward references will get lost.
Since all the global metadata should have already been resolved by the
time we get to the function metadata blocks we just need to check for
that case.  (If for some reason we need to handle bitcode that fails the
checks in r265223, the fix is to store about-to-be-dropped unresolved
nodes in MetadataList::shrinkTo until they can be handled succesfully by
a future call to MetadataList::tryToResolveCycles.)

llvm-svn: 265226
2016-04-02 15:22:57 +00:00
Manman Ren
ad40523f14 Swift Calling Convention: add swifterror attribute.
A ``swifterror`` attribute can be applied to a function parameter or an
AllocaInst.

This commit does not include any target-specific change. The target-specific
optimization will come as a follow-up patch.

Differential Revision: http://reviews.llvm.org/D18092

llvm-svn: 265189
2016-04-01 21:41:15 +00:00
Mehdi Amini
fcc69cbc7e Add a module Hash in the bitcode and the combined index, implementing a kind of "build-id"
This is intended to be used for ThinLTO incremental build.

Differential Revision: http://reviews.llvm.org/D18213

This is a recommit of r265095 after fixing the Windows issues.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265111
2016-04-01 05:33:11 +00:00
Mehdi Amini
b50dad82a8 Revert "Add support for computing SHA1 in LLVM"
This reverts commit r265096, r265095, and r265094.
Windows build is broken, and the validation does not pass.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265102
2016-04-01 03:03:21 +00:00
Mehdi Amini
e1ba9e8e87 Add missing test for the "Module hash in bitcode" added in r265095
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265096
2016-04-01 01:37:52 +00:00
Mehdi Amini
d897a705f9 Add a module Hash in the bitcode and the combined index, implementing a kind of "build-id"
This is intended to be used for ThinLTO incremental build.

Differential Revision: http://reviews.llvm.org/D18213

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265095
2016-04-01 01:30:06 +00:00
Adrian Prantl
1653aa9f14 testcase gardening: update the emissionKind enum to the new syntax. (NFC)
llvm-svn: 265081
2016-04-01 00:16:49 +00:00
Davide Italiano
d2518a5d0c [DebugInfo] Subprograms should belong to a CU.
Start fixing tests accordingly. There are still
about 35 failures before we can enable this check
in the IR verifier.

llvm-svn: 264990
2016-03-31 03:40:07 +00:00
Manman Ren
620c905661 Swift Calling Convention: add swiftself attribute.
Differential Revision: http://reviews.llvm.org/D17866

llvm-svn: 264754
2016-03-29 17:37:21 +00:00
Duncan P. N. Exon Smith
4c3b875a0b BitcodeReader: Allow METADATA_STRINGS to only have !""
Support parsing a METADATA_STRINGS record that only has a single piece
of metadata, !"".  Fixes a corner case in r264551.

llvm-svn: 264699
2016-03-29 05:25:17 +00:00
Duncan P. N. Exon Smith
1fbdccf334 Reapply ~"Bitcode: Collect all MDString records into a single blob"
Spiritually reapply commit r264409 (reverted in r264410), albeit with a
bit of a redesign.

Firstly, avoid splitting the big blob into multiple chunks of strings.

r264409 imposed an arbitrary limit to avoid a massive allocation on the
shared 'Record' SmallVector.  The bug with that commit only reproduced
when there were more than "chunk-size" strings.  A test for this would
have been useless long-term, since we're liable to adjust the chunk-size
in the future.

Thus, eliminate the motivation for chunk-ing by storing the string sizes
in the blob.  Here's the layout:

    vbr6: # of strings
    vbr6: offset-to-blob
    blob:
       [vbr6]: string lengths
       [char]: concatenated strings

Secondly, make the output of llvm-bcanalyzer readable.

I noticed when debugging r264409 that llvm-bcanalyzer was outputting a
massive blob all in one line.  Past a small number, the strings were
impossible to split in my head, and the lines were way too long.  This
version adds support in llvm-bcanalyzer for pretty-printing.

    <STRINGS abbrevid=4 op0=3 op1=9/> num-strings = 3 {
      'abc'
      'def'
      'ghi'
    }

From the original commit:

Inspired by Mehdi's similar patch, http://reviews.llvm.org/D18342, this
should (a) slightly reduce bitcode size, since there is less record
overhead, and (b) greatly improve reading speed, since blobs are super
cheap to deserialize.

llvm-svn: 264551
2016-03-27 23:17:54 +00:00
Duncan P. N. Exon Smith
a6ffc80357 Support: Implement StreamingMemoryObject::getPointer
The implementation is fairly obvious.  This is preparation for using
some blobs in bitcode.

For clarity (and perhaps future-proofing?), I moved the call to
JumpToBit in BitstreamCursor::readRecord ahead of calling
MemoryObject::getPointer, since JumpToBit can theoretically (a) read
bytes, which (b) invalidates the blob pointer.

This isn't strictly necessary the two memory objects we have:

  - The return of RawMemoryObject::getPointer is valid until the memory
    object is destroyed.

  - StreamingMemoryObject::getPointer is valid until the next chunk is
    read from the stream.  Since the JumpToBit call is only going ahead
    to a word boundary, we'll never load another chunk.

However, reordering makes it clear by inspection that the blob returned
by BitstreamCursor::readRecord will be valid.

I added some tests for StreamingMemoryObject::getPointer and
BitstreamCursor::readRecord.

llvm-svn: 264549
2016-03-27 23:00:59 +00:00
Duncan P. N. Exon Smith
5f89dfaeae Revert "Bitcode: Collect all MDString records into a single blob"
This reverts commit r264409 since it failed to bootstrap:
http://lab.llvm.org:8080/green/job/clang-stage2-configure-Rlto_build/8302/

llvm-svn: 264410
2016-03-25 15:22:27 +00:00
Duncan P. N. Exon Smith
7b1e6b8367 Bitcode: Collect all MDString records into a single blob
Optimize output of MDStrings in bitcode.  This emits them in big blocks
(currently 1024) in a pair of records:
  - BULK_STRING_SIZES: the sizes of the strings in the block, and
  - BULK_STRING_DATA: a single blob, which is the concatenation of all
    the strings.

Inspired by Mehdi's similar patch, http://reviews.llvm.org/D18342, this
should (a) slightly reduce bitcode size, since there is less record
overhead, and (b) greatly improve reading speed, since blobs are super
cheap to deserialize.

I needed to add support for blobs to streaming input to get the test
suite passing.
  - StreamingMemoryObject::getPointer reads ahead and returns the
    address of the blob.
  - To avoid a possible reallocation of StreamingMemoryObject::Bytes,
    BitstreamCursor::readRecord needs to move the call to JumpToEnd
    forward so that getPointer is the last bitstream operation.

llvm-svn: 264409
2016-03-25 14:40:18 +00:00