Commit Graph

1430 Commits

Author SHA1 Message Date
Mehdi Amini 21c89dc920 Revert "[ThinLTO] Add an auto-hide feature"
This reverts commit r293918, one lld test does not pass.

llvm-svn: 293961
2017-02-02 23:20:36 +00:00
Mehdi Amini 97624fb1ec [ThinLTO] Add an auto-hide feature
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

llvm-svn: 293918
2017-02-02 18:31:35 +00:00
Mehdi Amini 827600deaf Revert "[ThinLTO] Add an auto-hide feature"
This reverts r293912, bots are broken.

llvm-svn: 293914
2017-02-02 18:24:37 +00:00
Mehdi Amini dc5a7444f0 [ThinLTO] Add an auto-hide feature
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

llvm-svn: 293912
2017-02-02 18:13:46 +00:00
Dehao Chen 0944a8c2ec Change debug-info-for-profiling from a TargetOption to a function attribute.
Summary: LTO requires the debug-info-for-profiling to be a function attribute.

Reviewers: echristo, mehdi_amini, dblaikie, probinson, aprantl

Reviewed By: mehdi_amini, dblaikie, aprantl

Subscribers: aprantl, probinson, ahatanak, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D29203

llvm-svn: 293833
2017-02-01 22:45:09 +00:00
Matthias Braun 8c209aa877 Cleanup dump() functions.
We had various variants of defining dump() functions in LLVM. Normalize
them (this should just consistently implement the things discussed in
http://lists.llvm.org/pipermail/cfe-dev/2014-January/034323.html

For reference:
- Public headers should just declare the dump() method but not use
  LLVM_DUMP_METHOD or #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- The definition of a dump method should look like this:
  #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  LLVM_DUMP_METHOD void MyClass::dump() {
    // print stuff to dbgs()...
  }
  #endif

llvm-svn: 293359
2017-01-28 02:02:38 +00:00
Ivan Krasin c05c9db364 Avoid using unspecified ordering in MetadataLoader::MetadataLoaderImpl::parseOneMetadata.
Summary:
MetadataLoader::MetadataLoaderImpl::parseOneMetadata uses
the following construct in a number of places:

```
MetadataList.assignValue(<...>, NextMetadataNo++);
```

There, NextMetadataNo gets incremented, and since the order
of arguments evaluation is not specified, that can happen
before or after other arguments are evaluated.

In a few cases the other arguments indirectly use NextMetadataNo.
For instance, it's

```
MetadataList.assignValue(
    GET_OR_DISTINCT(DIModule,
                    (Context, getMDOrNull(Record[1]),
                     getMDString(Record[2]), getMDString(Record[3]),
                     getMDString(Record[4]), getMDString(Record[5]))),
    NextMetadataNo++);
```

getMDOrNull calls getMD that uses NextMetadataNo:

```
MetadataList.getMetadataFwdRef(NextMetadataNo);
```

Therefore, the order of evaluation becomes important. That caused
a very subtle LLD crash that only happens if compiled with GCC or
if LLD is built with LTO. In the case if LLD is compiled with Clang
and regular linking mode, everything worked as intended.

This change extracts incrementing of NextMetadataNo outside of
the arguments list to guarantee the correct order of evaluation.

For the record, this has taken 3 days to track to the origin. It all
started with a ThinLTO bot in Chrome not being able to link a target
if debug info is enabled.

Reviewers: pcc, mehdi_amini

Reviewed By: mehdi_amini

Subscribers: aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D29204

llvm-svn: 293291
2017-01-27 15:54:49 +00:00
Mehdi Amini 3bb4d01db9 [ThinLTO] Fix lazy-loading of MDString instruction attachments
CFI is using intrinsics that takes MDString as arguments, and this
was broken during lazy-loading of metadata.

Differential Revision: https://reviews.llvm.org/D28916

llvm-svn: 292641
2017-01-20 20:29:16 +00:00
Mehdi Amini 2737989245 Add an assertion to PlaceholderQueue destructor, ensuring it has been flushed
llvm-svn: 292597
2017-01-20 10:18:32 +00:00
Mehdi Amini 67d2cc1fad [ThinLTO] Add a recursive step in Metadata lazy-loading
Summary:
Without this, we're stressing the RAUW of unique nodes,
which is a costly operation. This is intended to limit
the number of RAUW, and is very effective on the total
link-time of opt with ThinLTO, before:

  real 4m4.587s  user 15m3.401s  sys 0m23.616s

after:

  real 3m25.261s user 12m22.132s sys 0m24.152s

Reviewers: tejohnson, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28751

llvm-svn: 292420
2017-01-18 18:36:21 +00:00
Malcolm Parsons 17d266bc96 Remove unused lambda captures. NFC
llvm-svn: 291916
2017-01-13 17:12:16 +00:00
Benjamin Kramer 061f4a5fe6 Apply clang-tidy's performance-unnecessary-value-param to LLVM.
With some minor manual fixes for using function_ref instead of
std::function. No functional change intended.

llvm-svn: 291904
2017-01-13 14:39:03 +00:00
Mehdi Amini 7b0d145768 [ThinLTO] Fix lazy-loading of Metadata attachment, which left some Fwd ref behind
The change in r291362 was too agressive. We still need to flush at the
end of the block because function local metadata can introduce fwd
ref as well.
(Bootstrap with ThinLTO was broken)

llvm-svn: 291379
2017-01-08 00:44:45 +00:00
Mehdi Amini d5549f3dac [ThinLTO] Fix assertions on lazy-loading of Metadata TBAA attachments
Summary:
The issue happens with:

 %0 = ....., !tbaa !0
 %1 = ....., !tbaa !1

With !0 that references !1.

In this case when loading !0 we generates a temporary for the
operand !1. We now flush it immediately and trigger the load of
!1 before moving on. If we don't we get the temporary when
attaching to %1. This is usually not an issue except that we
eagerly try to update TBAA MDNodes, which is obviously not possible
if we only have a temporary.

Differential Revision: https://reviews.llvm.org/D28423

llvm-svn: 291362
2017-01-07 20:24:23 +00:00
Mehdi Amini 42ef199058 [Bitcode] Remove unused PlaceHolder parameter to lazyLoadModuleMetadataBlock()
llvm-svn: 291356
2017-01-07 18:31:38 +00:00
Teresa Johnson 6c475a7595 ThinLTO: add early "dead-stripping" on the Index
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
2017-01-05 21:34:18 +00:00
Teresa Johnson 519465b993 [ThinLTO] Subsume all importing checks into a single flag
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

llvm-svn: 291108
2017-01-05 14:32:16 +00:00
Mehdi Amini 19ef4fad91 Use lazy-loading of Metadata in MetadataLoader when importing is enabled (NFC)
Summary:
This is a relatively simple scheme: we use the index emitted in the
bitcode to avoid loading all the global metadata. Instead we load
the index with their position in the bitcode so that we can load each
of them individually. Materializing the global metadata block in this
condition only triggers loading the named metadata, and the ones
referenced from there (transitively). When materializing a function,
metadata from the global block are loaded lazily as they are
referenced.

Two main current limitations are:

1) Global values other than functions are not materialized on demand,
so we need to eagerly load METADATA_GLOBAL_DECL_ATTACHMENT records
(and their transitive dependencies).
2) When we load a single metadata, we don't recurse on the operands,
instead we use a placeholder or a temporary metadata. Unfortunately
tepmorary nodes are very expensive. This is why we don't have it
always enabled and only for importing.

These two limitations can be lifted in a subsequent improvement if
needed.

With this change, the total link time of opt with ThinLTO and Debug
Info enabled is going down from 282s to 224s (~20%).

Reviewers: pcc, tejohnson, dexonsmith

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28113

llvm-svn: 291027
2017-01-04 22:54:33 +00:00
Mehdi Amini 867aad1359 Change BitstreamCursor::skipRecord to return the record code (NFC)
llvm-svn: 291026
2017-01-04 22:54:14 +00:00
David Blaikie 7ad9dc11db Reapply "Make BitCodeAbbrev ownership explicit using shared_ptr rather than IntrusiveRefCntPtr""
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.

llvm-svn: 291016
2017-01-04 22:36:33 +00:00
David Blaikie 6e2207a134 Revert "Make BitCodeAbbrev ownership explicit using shared_ptr rather than IntrusiveRefCntPtr"
Breaks Clang's use of bitcode. Reverting until I have a fix to go with
it there.

This reverts commit r291006.

llvm-svn: 291007
2017-01-04 21:19:28 +00:00
David Blaikie daff78cd87 Make BitCodeAbbrev ownership explicit using shared_ptr rather than IntrusiveRefCntPtr
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).

llvm-svn: 291006
2017-01-04 21:13:35 +00:00
Teresa Johnson 5a8dba5bda [ThinLTO] Import type as decl only when non-null Identifier
As per post-commit review for r289993 (D27775), we can only safely
import a type as a decl if it has an Identifier, as the Name alone
is not enough to be unique across modules.

llvm-svn: 290915
2017-01-03 23:19:29 +00:00
Mehdi Amini 5022bb7238 Change Metadata Index emission in the bitcode to use 2x32 bits for the placeholder
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.

llvm-svn: 290693
2016-12-28 23:45:54 +00:00
Mehdi Amini e98f925834 Add an index for Module Metadata record in the bitcode
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

llvm-svn: 290690
2016-12-28 22:30:28 +00:00
Saleem Abdulrasool 2b59eca1f7 Revert "Add an index for Module Metadata record in the bitcode"
This reverts commit a0ca6ae2d38339e4ede0dfa588086fc23d87e836.  Revert at
Mehdi's request as it is breaking bots.

llvm-svn: 290686
2016-12-28 20:37:22 +00:00
Mehdi Amini 32ca148198 Add an index for Module Metadata record in the bitcode
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

llvm-svn: 290684
2016-12-28 19:44:19 +00:00
Amjad Aboud 7faeecc8f7 [DebugInfo] Added support for Checksum debug info feature.
Differential Revision: https://reviews.llvm.org/D27642

llvm-svn: 290514
2016-12-25 10:12:09 +00:00
Mehdi Amini 690952d15e MetadataLoader: replace the tracking of ForwardReferences and UnresolvedNodes with a set-based solution (NFC)
This makes it explicit what is the exact list to handle, and it
looks much more easy to manipulate and understand that the
previous custom tracking of min/max to express the range where
to look for.

Differential Revision: https://reviews.llvm.org/D28089

llvm-svn: 290507
2016-12-25 04:22:54 +00:00
Mehdi Amini 4f90ee0010 MetadataLoader: add an extra assertion in Placeholders flush (NFC)
We don't expect any forward reference at this point.

llvm-svn: 290506
2016-12-25 03:55:53 +00:00
Mehdi Amini 9f926f70c1 MetadataLoader: split the creation of a single metadata out of a Record into its own function (NFC)
This is pure code motion, will just make it more reusable when I'll
attempt to lazy-load Metadats on-demand.

llvm-svn: 290414
2016-12-23 03:59:18 +00:00
Mehdi Amini 37c178b6f5 MetadataLoader: Reinitialize MinFwdRef/MaxFwdRef after resolving cycles (NFC)
This put the Loader back in a consistent state.

llvm-svn: 290409
2016-12-23 02:20:12 +00:00
Mehdi Amini 5ae6170fc2 MetadataLoader: Add an assertion for the implicit invariant of PlaceHolder while loading Metadata (NFC)
llvm-svn: 290408
2016-12-23 02:20:09 +00:00
Mehdi Amini 70a9cd4cbe MetadataLoader: Make sure every member of MetadataLoader are initialized (NFC)
llvm-svn: 290407
2016-12-23 02:20:07 +00:00
Mehdi Amini ec68dd49bf MetadataLoader: Refactor "IsImporting" into the Pimpl for the MetadataLoader (NFC)
Keeping all the state together will make it easier to handle.

llvm-svn: 290406
2016-12-23 02:20:02 +00:00
Peter Collingbourne 704f814a5e Clear the PendingTypeTests vector after moving from it.
This is to put the vector into a well defined state. Apparently the state of a
vector after being moved from is valid but unspecified. Found with clang-tidy.

llvm-svn: 290298
2016-12-22 02:52:23 +00:00
Peter Collingbourne 1b4137a7f9 IR: Function summary representation for type tests.
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

llvm-svn: 290280
2016-12-21 23:03:45 +00:00
Peter Collingbourne 0c30f089d5 IR: Eliminate non-determinism in the module summary analysis.
Also make the summary ref and call graph vectors immutable. This means
a smaller API surface and fewer places to audit for non-determinism.

Differential Revision: https://reviews.llvm.org/D27875

llvm-svn: 290200
2016-12-20 21:12:28 +00:00
Adrian Prantl bceaaa9643 [IR] Remove the DIExpression field from DIGlobalVariable.
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

llvm-svn: 290153
2016-12-20 02:09:43 +00:00
Teresa Johnson a61f5e3796 [ThinLTO] Import composite types as declarations
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
2016-12-16 21:25:01 +00:00
Adrian Prantl 73ec065604 Revert "[IR] Remove the DIExpression field from DIGlobalVariable."
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!

llvm-svn: 289982
2016-12-16 19:39:01 +00:00
Mehdi Amini 8662305bae Strip invalid TBAA when reading bitcode
This ensures backward compatibility on bitcode loading.

Differential Revision: https://reviews.llvm.org/D27839

llvm-svn: 289977
2016-12-16 19:16:29 +00:00
Adrian Prantl 74a835cda0 [IR] Remove the DIExpression field from DIGlobalVariable.
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

llvm-svn: 289920
2016-12-16 04:25:54 +00:00
Adrian Prantl 03c6d31a3b Revert "[IR] Remove the DIExpression field from DIGlobalVariable."
This reverts commit 289902 while investigating bot berakage.

llvm-svn: 289906
2016-12-16 01:00:30 +00:00
Adrian Prantl ce13935776 [IR] Remove the DIExpression field from DIGlobalVariable.
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

llvm-svn: 289902
2016-12-16 00:36:43 +00:00
Stephan Bergmann 17c7f70362 Replace APFloatBase static fltSemantics data members with getter functions
At least the plugin used by the LibreOffice build
(<https://wiki.documentfoundation.org/Development/Clang_plugins>) indirectly
uses those members (through inline functions in LLVM/Clang include files in turn
using them), but they are not exported by utils/extract_symbols.py on Windows,
and accessing data across DLL/EXE boundaries on Windows is generally
problematic.

Differential Revision: https://reviews.llvm.org/D26671

llvm-svn: 289647
2016-12-14 11:57:17 +00:00
Nico Weber b3901bdde8 Fix MSVC build after 289461; MSVC isn't sure if this is std:: or llvm::
llvm-svn: 289480
2016-12-12 22:46:40 +00:00
Mehdi Amini ef27db879c Refactor BitcodeReader: move Metadata and ValueId handling in their own class/file
Summary:
I'm planning on changing the way we load metadata to enable laziness.
I'm getting lost in this gigantic files, and gigantic class that is the bitcode
reader. This is a first toward splitting it in a few coarse components that
are more easily understandable.

Reviewers: pcc, tejohnson

Subscribers: mgorny, llvm-commits, dexonsmith

Differential Revision: https://reviews.llvm.org/D27646

llvm-svn: 289461
2016-12-12 19:34:26 +00:00
Mehdi Amini bf2090e31a Remove IsMetadataMaterialized from BitcodeReader (NFC)
Summary: It does not seem useful.

Reviewers: pcc, dexonsmith

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D27668

llvm-svn: 289457
2016-12-12 19:23:39 +00:00
Dimitry Andric 59e5cb4342 Fix compile with GCC 5 or later
Summary:

Compiling with GCC 5 or later can fail with a bogus error "constructor
required before non-static data member for
llvm::ValueEnumerator::MDRange::First has been parsed".

This was originally fixed upstream in GCC PR 70528, but later this fix
was reverted, and released versions of GCC still show the bogus error.

To work around this, replace MDRange's declaration of a default
constructor with a definition.

Reviewers: dexonsmith, rsmith, rivanvx

Subscribers: llvm-commits, dim, dexonsmith

Differential Revision: https://reviews.llvm.org/D18730

llvm-svn: 289454
2016-12-12 19:05:52 +00:00
Simon Pilgrim 9335c020c6 Fix MSVC bool to uint64_t promotion warning
llvm-svn: 288796
2016-12-06 11:12:53 +00:00
Adrian Prantl 941fa7588b [DIExpression] Introduce a dedicated DW_OP_LLVM_fragment operation
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

llvm-svn: 288683
2016-12-05 18:04:47 +00:00
Peter Collingbourne 57f9b8c5b5 Bitcode: The index used by ModuleSummaryIndexBitcodeReader is now required, so make it a reference. NFCI.
llvm-svn: 288318
2016-12-01 06:21:08 +00:00
Peter Collingbourne a46ec9f0a8 Bitcode: Introduce BitcodeModule::{has,get}Summary().
These are equivalent to hasGlobalValueSummary() and getModuleSummaryIndex().

Differential Revision: https://reviews.llvm.org/D27242

llvm-svn: 288317
2016-12-01 06:00:53 +00:00
Peter Collingbourne cf2750a501 Bitcode: Correctly handle Fixed and VBR arrays in BitstreamCursor::skipRecord().
The assertions were wrong; we need to call getEncodingData() on the element,
not the array. While here, simplify the skipRecord() implementation for Fixed
and Char6 arrays. This is tested by the code I added to llvm-bcanalyzer
which makes sure that we can skip any record.

Differential Revision: https://reviews.llvm.org/D27241

llvm-svn: 288315
2016-12-01 05:47:58 +00:00
Peter Collingbourne 5a0a2e648c Bitcode: Introduce BitcodeWriter interface.
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

llvm-svn: 288195
2016-11-29 20:43:47 +00:00
Peter Collingbourne bfcf9800b8 Bitcode: Change expected layout of module blocks.
We now expect each module's identification block to appear immediately before
the module block. Any module block that appears without an identification block
immediately before it is interpreted as if it does not have a module block.

Also change the interpretation of VST and function offsets in bitcode.
The offset is always taken as relative to the start of the identification
(or module if not present) block, minus one word. This corresponds to the
historical interpretation of offsets, i.e. relative to the start of the file.

These changes allow for bitcode modules to be concatenated by copying bytes.

Differential Revision: https://reviews.llvm.org/D27184

llvm-svn: 288098
2016-11-29 02:27:04 +00:00
Chris Bieneman 05c279fc4b [CMake] NFC. Updating CMake dependency specifications
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
2016-11-17 04:36:50 +00:00
Peter Collingbourne 7a74803abf Bitcode: Introduce initial multi-module reader API.
Implement getLazyBitcodeModule() and parseBitcodeFile() in terms of it.

Differential Revision: https://reviews.llvm.org/D26719

llvm-svn: 287156
2016-11-16 21:44:45 +00:00
Teresa Johnson 3624bdf60a Restore "[ThinLTO] Prevent exporting of locals used/defined in module level asm"
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.

llvm-svn: 286844
2016-11-14 17:12:32 +00:00
Teresa Johnson d5033a4576 [ThinLTO] Make inline assembly handling more efficient in summary
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

llvm-svn: 286840
2016-11-14 16:40:19 +00:00
Eric Fiselier c79c9d8536 Add explicit (void) cast to unused unique_ptr::release() results
Summary:
This patch adds explicit `(void)` casts to discarded `release()` calls to suppress -Wunused-result.

This patch fixes *all* warnings are generated as a result of [applying `[[nodiscard]]`  within libc++](https://reviews.llvm.org/D26596).
Similar fixes were applied to Clang in r286796.

Reviewers: chandlerc, dberris

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D26598

llvm-svn: 286797
2016-11-14 07:26:17 +00:00
Peter Collingbourne d9445c49ad Bitcode: Change module reader functions to return an llvm::Expected.
Differential Revision: https://reviews.llvm.org/D26562

llvm-svn: 286752
2016-11-13 07:00:17 +00:00
Peter Collingbourne 9ef5a8c501 Bitcode: More precise casting. NFCI.
llvm-svn: 286750
2016-11-13 06:59:28 +00:00
Peter Collingbourne 6de481a378 Bitcode: Change getModuleSummaryIndex() to return an llvm::Expected.
Differential Revision: https://reviews.llvm.org/D26539

llvm-svn: 286624
2016-11-11 19:50:39 +00:00
Peter Collingbourne cd513a41c1 Bitcode: Clean up error handling for certain bitcode query functions.
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
2016-11-11 19:50:24 +00:00
Peter Collingbourne c0032b7178 Bitcode: Prepare to move bitcode readers to free functions.
Make initStream() a free function, and change BitcodeReaderBase ctor to take
a BitstreamCursor.

llvm-svn: 286622
2016-11-11 19:50:10 +00:00
Teresa Johnson ad17679abd Split Bitcode/ReaderWriter.h into separate reader and writer headers
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
2016-11-11 05:34:58 +00:00
Mehdi Amini c1edf566b9 Prevent at compile time converting from Error::success() to Expected<T>
This would trigger an assertion at runtime otherwise.

Differential Revision: https://reviews.llvm.org/D26482

llvm-svn: 286562
2016-11-11 04:29:25 +00:00
Peter Collingbourne d93620bf4d IR: Introduce inrange attribute on getelementptr indices.
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

llvm-svn: 286514
2016-11-10 22:34:55 +00:00
Mehdi Amini 67d1a41226 Make BitcodeReader::parseIdentificationBlock() robust to EOF
This method is particular: it iterates at the top-level and does
not have an enclosing block.

llvm-svn: 286394
2016-11-09 21:26:49 +00:00
Peter Collingbourne 7f00d0a125 Bitcode: Change the materializer interface to return llvm::Error.
Differential Revision: https://reviews.llvm.org/D26439

llvm-svn: 286382
2016-11-09 17:49:19 +00:00
Mehdi Amini b6a11a7879 Revert "[ThinLTO] Prevent exporting of locals used/defined in module level asm"
This reverts commit r286297.
Introduces a dependency from libAnalysis to libObject, which I missed
during the review.

llvm-svn: 286329
2016-11-09 01:45:13 +00:00
Peter Collingbourne 7576cb0fa7 Bitcode: Remove the remnants of the BitcodeDiagnosticInfo class.
The BitcodeReader no longer produces BitcodeDiagnosticInfo diagnostics.
The only remaining reference was in the gold plugin; the code there has been
dead since we stopped producing InvalidBitcodeSignature error codes in r225562.
While at it remove the InvalidBitcodeSignature error code.

llvm-svn: 286326
2016-11-09 01:09:11 +00:00
Peter Collingbourne 58f7f0759f Bitcode: Change the BitcodeReader to use llvm::Error internally.
Differential Revision: https://reviews.llvm.org/D26430

llvm-svn: 286323
2016-11-09 00:51:04 +00:00
Teresa Johnson 6955feebf3 [ThinLTO] Prevent exporting of locals used/defined in module level asm
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

llvm-svn: 286297
2016-11-08 21:53:35 +00:00
Peter Collingbourne e2dcf7c3a1 IR, Bitcode: Change bitcode reader to no longer own its memory buffer.
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
2016-11-08 06:03:43 +00:00
Peter Collingbourne 77c89b6958 Bitcode: Decouple block info block state from reader.
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106630.html

Move block info block state to a new class, BitstreamBlockInfo.
Clients may set the block info for a particular cursor with the
BitstreamCursor::setBlockInfo() method.

At this point BitstreamReader is not much more than a container for an
ArrayRef<uint8_t>, so remove it and replace all uses with direct uses
of memory buffers.

Differential Revision: https://reviews.llvm.org/D26259

llvm-svn: 286207
2016-11-08 04:17:11 +00:00
Peter Collingbourne 939c7d916e Bitcode: Split out block info reading into a separate function.
We're about to make this more complicated.

llvm-svn: 286206
2016-11-08 04:16:57 +00:00
Benjamin Kramer f15a8e6a50 [BitcodeWriter] Replace a manual byteswap with read32be.
No functional change intended.

llvm-svn: 286066
2016-11-06 13:26:39 +00:00
Amaury Sechet 74084c44ca Kill deprecated attribute API
Summary:
This kill various depreacated API related to attribute :
 - The deprecated C API attribute based on LLVMAttribute enum.
 - The Raw attribute set format (planned to be removed in 4.0).

Reviewers: bkramer, echristo, mehdi_amini, void

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D23039

llvm-svn: 286062
2016-11-06 07:48:46 +00:00
Adrian Prantl dbfda63695 Add DWARF debug info support for C++11 inline namespaces.
This implements the DWARF 5 DW_AT_export_symbols feature:
http://dwarfstd.org/ShowIssue.php?issue=141212.1

<rdar://problem/18616046>

llvm-svn: 285959
2016-11-03 19:42:02 +00:00
Peter Collingbourne ff2c2ec6b2 Bitcode: Check file size before reading bitcode header.
Should unbreak ocaml binding tests.

Also added an llvm-dis test that checks for the same thing.

llvm-svn: 285777
2016-11-02 00:39:11 +00:00
Peter Collingbourne 028eb5a3f8 Bitcode: Change reader interface to take memory buffers.
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106595.html

This change also fixes an API oddity where BitstreamCursor::Read() would
return zero for the first read past the end of the bitstream, but would
report_fatal_error for subsequent reads. Now we always report_fatal_error
for all reads past the end. Updated clients to check for the end of the
bitstream before reading from it.

I also needed to add padding to the invalid bitcode tests in
test/Bitcode/. This is because the streaming interface was not checking that
the file size is a multiple of 4.

Differential Revision: https://reviews.llvm.org/D26219

llvm-svn: 285773
2016-11-02 00:08:19 +00:00
Peter Collingbourne d3a6c70b2d Bitcode: Simplify BitstreamWriter::EnterBlockInfoBlock() interface.
No block info block should need to define local abbreviations, so we can
always use a code width of 2.

Also change all block info block writers to use EnterBlockInfoBlock.

Differential Revision: https://reviews.llvm.org/D26168

llvm-svn: 285660
2016-11-01 01:18:57 +00:00
Teresa Johnson 7c31cb1665 [ThinLTO] Use flags from summary when writing variable summary (NFC)
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.

llvm-svn: 285433
2016-10-28 19:36:00 +00:00
Teresa Johnson 02563cd3a6 [ThinLTO] Create AliasSummary when building index
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

llvm-svn: 285379
2016-10-28 02:39:38 +00:00
Teresa Johnson 58fbc916a0 [ThinLTO] Rename HasSection to NoRename (NFC)
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

llvm-svn: 285376
2016-10-28 02:24:59 +00:00
Peter Collingbourne fc0a99bfda BitcodeReader: Require clients to read the block info block at most once.
This change makes it the client's responsibility to call ReadBlockInfoBlock()
at most once. This is in preparation for a future change that will allow
there to be multiple block info blocks.

See also: http://lists.llvm.org/pipermail/llvm-dev/2016-October/106512.html

Differential Revision: https://reviews.llvm.org/D26016

llvm-svn: 285350
2016-10-27 21:39:28 +00:00
Victor Leschuk a37660c669 DebugInfo: fix incorrect alignment type (NFC)
Change type of some missed DebugInfo-related alignment variables,
that are still uint64_t, to uint32_t.

Original change introduced in r284482.

llvm-svn: 285242
2016-10-26 21:32:29 +00:00
Simon Pilgrim 25059360d5 Fix spelling mistake in comment.
llvm-svn: 284714
2016-10-20 10:42:14 +00:00
Simon Pilgrim 071da46a35 Fix MSVC bool -> uint64_t promotion warning
llvm-svn: 284713
2016-10-20 10:37:58 +00:00
Victor Leschuk 2ede126b1b DebugInfo: preparation to implement DW_AT_alignment
- 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

llvm-svn: 284678
2016-10-20 00:13:12 +00:00
Reid Kleckner 990504e625 Remove LLVM_NOEXCEPT and replace it with noexcept
Now that we have dropped MSVC 2013, all supported compilers support
noexcept and we can drop this portability macro.

llvm-svn: 284672
2016-10-19 23:52:38 +00:00
Victor Leschuk 197aa3192d DebugInfo: change alignment type from uint64_t to uint32_t to save space.
In futher patches we shall have alignment field added to DIVariable family
and switching from uint64_t to uint32_t will save 4 bytes per variable.

Differential Revision: https://reviews.llvm.org/D25620

llvm-svn: 284482
2016-10-18 14:31:22 +00:00
Mehdi Amini 00fa1409ec ThinLTO: handles modules with empty summaries
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
2016-10-08 04:44:18 +00:00
Mehdi Amini 117296c0a0 Use StringRef in Pass/PassManager APIs (NFC)
llvm-svn: 283004
2016-10-01 02:56:57 +00:00
Piotr Padlewski d9830eb79f [thinlto] Basic thinlto fdo heuristic
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
2016-09-26 20:37:32 +00:00
Peter Collingbourne 6e8607527c BitcodeReader: Deduplicate code. NFC.
Differential Revision: https://reviews.llvm.org/D24852

llvm-svn: 282272
2016-09-23 18:27:42 +00:00
Teresa Johnson 620c140a9b [ThinLTO] Always emit a summary when compiling in ThinLTO mode
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
2016-09-20 23:07:17 +00:00