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

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

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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/

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

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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 siz

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

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Bitcode: Stop using MODULE_CODE_METADATA_VALUES

The motivation for MODULE_CODE_METADATA_VALUES was to enable an
-flto=thin scheme where:

1. First, one function is cherry-picked from a bitcode file

Bitcode: Stop using MODULE_CODE_METADATA_VALUES

The motivation for MODULE_CODE_METADATA_VALUES was to enable an
-flto=thin scheme where:

1. First, one function is cherry-picked from a bitcode file.
2. Later, another function is cherry-picked.
3. Later, ...
4. Finally, the metadata needed by all the previous functions is
loaded.

This was abandoned in favour of:

1. Calculate the superset of functions needed from a Module.
2. Link all functions at once.

Delayed metadata reading no longer serves a purpose. It also adds
a few complication, since we can't count on metadata being properly
parsed when exiting the BitcodeReader. After discussing with Teresa, we
agreed to remove it.

The code that depended on this was removed/updated in r264326.

llvm-svn: 264378

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IR: Stop upgrading !llvm.loop attachments via MDString

Remove logic to upgrade !llvm.loop by changing the MDString tag
directly. This old logic would check (and change) arbitrary strings
that had n

IR: Stop upgrading !llvm.loop attachments via MDString

Remove logic to upgrade !llvm.loop by changing the MDString tag
directly. This old logic would check (and change) arbitrary strings
that had nothing to do with loop metadata. Instead, check !llvm.loop
attachments directly, and change which strings get attached.

Rather than updating the assembly-based upgrade, drop it entirely. It
has been quite a while since we supported upgrading textual IR.

llvm-svn: 264373

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Bitcode: Error out instead of crashing on corrupt metadata

I hit a crash in the bitcode reader on some corrupt input where an
MDString had somehow been attached to an instruction instead of an
MDNod

Bitcode: Error out instead of crashing on corrupt metadata

I hit a crash in the bitcode reader on some corrupt input where an
MDString had somehow been attached to an instruction instead of an
MDNode. This input is pretty bogus, but we shouldn't be crashing on bad
input here.

This change adds error handling in all of the places where we
currently have unchecked casts from Metadata to MDNode, which means
we'll error out instead of crashing for that sort of input.

Unfortunately, I don't have tests. Hitting this requires flipping bits
in the input bitcode, and committing corrupt binary files to catch
these cases is a bit too opaque and unmaintainable.

llvm-svn: 263742

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Upgrade TBAA *before* upgrading intrinsics

Summary: If TBAA is on an intrinsic and it gets upgraded and drops the TBAA we hit an odd assert. We should just upgrade the TBAA first because it doesn't

Upgrade TBAA *before* upgrading intrinsics

Summary: If TBAA is on an intrinsic and it gets upgraded and drops the TBAA we hit an odd assert. We should just upgrade the TBAA first because it doesn't have side-effects.

Reviewers: reames, apilipenko, manmanren

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D18229

llvm-svn: 263673

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Move global ID computation from Function to GlobalValue (NFC)

Since the static getGlobalIdentifier and getGUID methods are now called
for global values other than functions, reflect that by moving t

Move global ID computation from Function to GlobalValue (NFC)

Since the static getGlobalIdentifier and getGUID methods are now called
for global values other than functions, reflect that by moving these
methods to the GlobalValue class.

llvm-svn: 263524

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[ThinLTO] Renaming of function index to module summary index (NFC)

(Resubmitting after fixing missing file issue)

With the changes in r263275, there are now more than just functions in
the summary.

[ThinLTO] Renaming of function index to module summary index (NFC)

(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.

llvm-svn: 263513

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Revert "[ThinLTO] Renaming of function index to module summary index (NFC)"

This reverts commit r263490. Missed a file.

llvm-svn: 263493

[ThinLTO] Renaming of function index to module summary index (NFC)

With the changes in r263275, there are now more than just functions in
the summary. Completed the renaming of data structures (star

[ThinLTO] Renaming of function index to module summary index (NFC)

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.

llvm-svn: 263490

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[ThinLTO] Support for reference graph in per-module and combined summary.

Summary:
This patch adds support for including a full reference graph including
call graph edges and other GV references in

[ThinLTO] Support for reference graph in per-module and combined summary.

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

llvm-svn: 263275

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[ThinLTO] Add missing breaks when parsing summaries (NFC)

This wasn't causing a correctness issue, but was causing extra duplicate
entries to be added to the SummaryMap.

llvm-svn: 261757

Restore "[ThinLTO] Use MD5 hash in function index." with fix

This restores commit r260408, along with a fix for a bot failure.

The bot failure was caused by dereferencing a unique_ptr in the same
c

Restore "[ThinLTO] Use MD5 hash in function index." with fix

This restores commit r260408, along with a fix for a bot failure.

The bot failure was caused by dereferencing a unique_ptr in the same
call instruction parameter list where it was passed via std::move.
Apparently due to luck this was not exposed when I built the compiler
with clang, only with gcc.

llvm-svn: 260442

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Revert "[ThinLTO] Use MD5 hash in function index." due to bot failure

This reverts commit r260408. Bot failure that I need to investigate.

llvm-svn: 260412

[ThinLTO] Use MD5 hash in function index.

Summary:
This patch uses the lower 64-bits of the MD5 hash of a function name as
a GUID in the function index, instead of storing function names. Any
local

[ThinLTO] Use MD5 hash in function index.

Summary:
This patch uses the lower 64-bits of the MD5 hash of a function name as
a GUID in the function index, instead of storing function names. Any
local functions are first given a global name by prepending the original
source file name. This is the same naming scheme and GUID used by PGO in
the indexed profile format.

This change has a couple of benefits. The primary benefit is size
reduction in the combined index file, for example 483.xalancbmk's
combined index file was reduced by around 70%. It should also result in
memory savings for the index file in memory, as the in-memory map is
also indexed by the hash instead of the string.

Second, this enables integration with indirect call promotion, since the
indirect call profile targets are recorded using the same global naming
convention and hash. This will enable the function importer to easily
locate function summaries for indirect call profile targets to enable
their import and subsequent promotion.

The original source file name is recorded in the bitcode in a new
module-level record for use in the ThinLTO backend pipeline.

Reviewers: davidxl, joker.eph

Subscribers: llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D17028

llvm-svn: 260408

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Fix VST_CODE_* bitcode id comments (NFC)

llvm-svn: 260382

[ThinLTO] Include linkage type in function summary

Summary:
Adds the linkage type to both the per-module and combined function
summaries, which subsumes the current islocal bit. This will eventually

[ThinLTO] Include linkage type in function summary

Summary:
Adds the linkage type to both the per-module and combined function
summaries, which subsumes the current islocal bit. This will eventually
be used to optimized linkage types based on global summary-based
analysis.

Reviewers: joker.eph

Subscribers: joker.eph, davidxl, llvm-commits

Differential Revision: http://reviews.llvm.org/D16943

llvm-svn: 259993

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Fix Clang-tidy modernize-use-nullptr and modernize-use-override warnings; other minor fixes.

Differential revision: reviews.llvm.org/D16568

llvm-svn: 258831

[ThinLTO] Avoid unnecesary hash lookups during metadata linking (NFC)

Replace sequences of count() followed by operator[] with either
find() or insert(), depending on the context.

llvm-svn: 258405

Fix typo in an error string. NFC.

llvm-svn: 258357

Bring back "Assert that we have all use/users in the getters."

This reverts commit r257751, bringing back r256105.

The problem the assert found was fixed in r257915.

Original commit message:

Asse

Bring back "Assert that we have all use/users in the getters."

This reverts commit r257751, bringing back r256105.

The problem the assert found was fixed in r257915.

Original commit message:

Assert that we have all use/users in the getters.

An error that is pretty easy to make is to use the lazy bitcode reader
and then do something like

if (V.use_empty())

The problem is that uses in unmaterialized functions are not accounted
for.

This patch adds asserts that all uses are known.

llvm-svn: 257920

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Revert "Assert that we have all use/users in the getters."

This reverts commit fdb838f3f8a8b6896bbbd5285555874eb3b748eb.

llvm-svn: 257751

Bitcode: Fix reading and writing of ConstantDataVectors of halfs

In r254991 I allowed ConstantDataVectors to contain elements of
HalfTy, but I missed updating the bitcode reader and writer to handle

Bitcode: Fix reading and writing of ConstantDataVectors of halfs

In r254991 I allowed ConstantDataVectors to contain elements of
HalfTy, but I missed updating the bitcode reader and writer to handle
this, so now we crash if we try to emit bitcode on programs that have
constant vectors of half.

This fixes the issue and adds test coverage for reading and writing
constant sequences in bitcode.

llvm-svn: 256982

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Ensure MDNode used as key in metadata linking map cannot be RAUWed

As suggested in review for r255909, add a way to ensure that temporary
MD used as keys in the MetadataToID map during ThinLTO impor

Ensure MDNode used as key in metadata linking map cannot be RAUWed

As suggested in review for r255909, add a way to ensure that temporary
MD used as keys in the MetadataToID map during ThinLTO importing are not
RAUWed.

Add support for marking an MDNode as not replaceable. Clear the new
CanReplace flag when adding a temporary MD node to the MetadataToID map
and clear it when destroying the map.

llvm-svn: 256648

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