205 Commits

Author SHA1 Message Date
Duncan P. N. Exon Smith
bc60a32a93 BitcodeWriter: Further unify function metadata, NFC
Further unify the handling of function-local metadata with global
metadata, by exposing the same interface in ValueEnumerator.  Both
contexts use the same accessors:

  - getMDStrings(): get the strings for this block.
  - getNonMDStrings(): get the non-strings for this block.

A future commit will start adding strings to the function-block.

llvm-svn: 265224
2016-04-02 15:09:42 +00:00
Duncan P. N. Exon Smith
1350530482 BitcodeWriter: Replace dead code with an assertion, NFC
The caller of ValueEnumerator::EnumerateOperandType never sends in
metadata.  Assert that, and remove the unnecessary logic.

llvm-svn: 264558
2016-03-28 00:03:12 +00:00
Duncan P. N. Exon Smith
66701f0f24 BitcodeWriter: Simplify tracking of function-local metadata, NFC
We don't really need a separate vector here; instead, point at a range
inside the main MDs array.  This matches how r264551 references the
ranges of strings and non-strings.

llvm-svn: 264552
2016-03-27 23:22:31 +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
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
Duncan P. N. Exon Smith
696d47896a Bitcode: Use std::stable_partition for reproducible builds
Caught by inspection while working on partitioning metadata.  It's nice
to produce the same bitcode if you run the compiler twice.

llvm-svn: 264381
2016-03-25 02:20:28 +00:00
Duncan P. N. Exon Smith
27bcd4da30 BitcodeWriter: Move abbreviation for GenericDINode; almost NFC
Simplify ValueEnumerator and WriteModuleMetadata by shifting the logic
for the METADATA_GENERIC_DEBUG abbreviation into WriteGenericDINode.
(This is just like r264302, but for GenericDINode.)

The only change is that the abbreviation is emitted later in the
bitcode, just before the first `GenericDINode` record.  This shouldn't
be observable though.

llvm-svn: 264303
2016-03-24 16:30:18 +00:00
Duncan P. N. Exon Smith
cc1d84c50c BitcodeWriter: Move abbreviation for DILocation; almost NFC
Simplify ValueEnumerator and WriteModuleMetadata by shifting the logic
for the METADATA_LOCATION abbreviation into WriteDILocation.

The only change is that the abbreviation is emitted later in the
bitcode, just before the first `DILocation` record.  This shouldn't be
observable though.

llvm-svn: 264302
2016-03-24 16:25:51 +00:00
Yaron Keren
d008c8f557 Annotate dump() methods with LLVM_DUMP_METHOD, addressing Richard Smith r259192 post commit comment.
clang part in r259232, this is the LLVM part of the patch.

llvm-svn: 259240
2016-01-29 20:50:44 +00:00
Teresa Johnson
b23b3067db Rename MDValue* to Metadata* (NFC)
Renamed MDValue* to Metadata*, and MDValueToValIDMap to MetadataToIDs,
as per review for r255909.

llvm-svn: 256593
2015-12-29 23:00:22 +00:00
Vedant Kumar
358f3ea995 Re-reapply "[IR] Move optional data in llvm::Function into a hungoff uselist"
Make personality functions, prefix data, and prologue data hungoff
operands of Function.

This is based on the email thread "[RFC] Clean up the way we store
optional Function data" on llvm-dev.

Thanks to sanjoyd, majnemer, rnk, loladiro, and dexonsmith for feedback!

Includes a fix to scrub value subclass data in dropAllReferences. Does not
use binary literals.

Differential Revision: http://reviews.llvm.org/D13829

llvm-svn: 256095
2015-12-19 08:52:49 +00:00
Vedant Kumar
2e1a683bae Revert "Reapply "[IR] Move optional data in llvm::Function into a hungoff uselist""
This reverts commit r256093.

This broke lld-x86_64-win7 because of -Werror,-Wc++1y-extensions.

llvm-svn: 256094
2015-12-19 08:48:43 +00:00
Vedant Kumar
c33a34516e Reapply "[IR] Move optional data in llvm::Function into a hungoff uselist"
Make personality functions, prefix data, and prologue data hungoff
operands of Function.

This is based on the email thread "[RFC] Clean up the way we store
optional Function data" on llvm-dev.

Thanks to sanjoyd, majnemer, rnk, loladiro, and dexonsmith for feedback!

Includes a fix to scrub value subclass data in dropAllReferences.

Differential Revision: http://reviews.llvm.org/D13829

llvm-svn: 256093
2015-12-19 08:29:51 +00:00
Vedant Kumar
6843b30188 Revert "[IR] Move optional data in llvm::Function into a hungoff uselist"
This reverts commit r256090.

This broke llvm-clang-lld-x86_64-debian-fast.

llvm-svn: 256091
2015-12-19 07:30:44 +00:00
Vedant Kumar
46b3967fa2 [IR] Move optional data in llvm::Function into a hungoff uselist
Make personality functions, prefix data, and prologue data hungoff
operands of Function.

This is based on the email thread "[RFC] Clean up the way we store
optional Function data" on llvm-dev.

Thanks to sanjoyd, majnemer, rnk, loladiro, and dexonsmith for feedback!

Differential Revision: http://reviews.llvm.org/D13829

llvm-svn: 256090
2015-12-19 07:08:56 +00:00
Duncan P. N. Exon Smith
49222f78ba BitcodeWriter: Stop using implicit ilist iterator conversion, NFC
Now LLVMBitWriter compiles without implicit ilist iterator conversions.

In these cases, the cleanest thing was to switch to range-based for
loops.  Since there wasn't much noise I converted sub-loops and parent
loops as a drive-by.

llvm-svn: 250144
2015-10-13 03:26:19 +00:00
Pete Cooper
c2ffa0891f Use foreach loop over constant operands. NFC.
A number of places had explicit loops over Constant::operands().
Just use foreach loops where possible.

llvm-svn: 240694
2015-06-25 20:51:38 +00:00
Alexander Kornienko
f993659b8f Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko
40cb19d802 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
David Majnemer
c8b1f095a3 Move the personality function from LandingPadInst to Function
The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

llvm-svn: 239940
2015-06-17 20:52:32 +00:00
Yaron Keren
5e21e81e4e Rangify several for loops in ValueEnumerator constructor.
llvm-svn: 239636
2015-06-12 20:18:20 +00:00
Duncan P. N. Exon Smith
09b5c9c24d IR: Give 'DI' prefix to debug info metadata
Finish off PR23080 by renaming the debug info IR constructs from `MD*`
to `DI*`.  The last of the `DIDescriptor` classes were deleted in
r235356, and the last of the related typedefs removed in r235413, so
this has all baked for about a week.

Note: If you have out-of-tree code (like a frontend), I recommend that
you get everything compiling and tests passing with the *previous*
commit before updating to this one.  It'll be easier to keep track of
what code is using the `DIDescriptor` hierarchy and what you've already
updated, and I think you're extremely unlikely to insert bugs.  YMMV of
course.

Back to *this* commit: I did this using the rename-md-di-nodes.sh
upgrade script I've attached to PR23080 (both code and testcases) and
filtered through clang-format-diff.py.  I edited the tests for
test/Assembler/invalid-generic-debug-node-*.ll by hand since the columns
were off-by-three.  It should work on your out-of-tree testcases (and
code, if you've followed the advice in the previous paragraph).

Some of the tests are in badly named files now (e.g.,
test/Assembler/invalid-mdcompositetype-missing-tag.ll should be
'dicompositetype'); I'll come back and move the files in a follow-up
commit.

llvm-svn: 236120
2015-04-29 16:38:44 +00:00
Duncan P. N. Exon Smith
c4adf5ea45 IR: Add assembly/bitcode support for function metadata attachments
Add serialization support for function metadata attachments (added in
r235783).  The syntax is:

    define @foo() !attach !0 {

Metadata attachments are only allowed on functions with bodies.  Since
they come before the `{`, they're not really part of the body; since
they require a body, they're not really part of the header.  In
`LLParser` I gave them a separate function called from `ParseDefine()`,
`ParseOptionalFunctionMetadata()`.

In bitcode, I'm using the same `METADATA_ATTACHMENT` record used by
instructions.  Instruction metadata attachments are included in a
special "attachment" block at the end of a `Function`.  The attachment
records are laid out like this:

    InstID (KindID MetadataID)+

Note that these records always have an odd number of fields.  The new
code takes advantage of this to recognize function attachments (which
don't need an instruction ID):

    (KindID MetadataID)+

This means we can use the same attachment block already used for
instructions.

This is part of PR23340.

llvm-svn: 235785
2015-04-24 22:04:41 +00:00
Duncan P. N. Exon Smith
94762eaaad uselistorder: Thread bit through ValueEnumerator
Canonicalize access to whether to preserve use-list order in bitcode on
a `bool` stored in `ValueEnumerator`.  Next step, expose this as a
`bool` through `WriteBitcodeToFile()`.

llvm-svn: 234956
2015-04-14 23:45:11 +00:00
Duncan P. N. Exon Smith
b8db6871b0 IR: Use the new DebugLoc API, NFC
Update lib/IR and lib/Bitcode to use the new `DebugLoc` API.  Added an
explicit conversion to `bool` (avoiding a conversion to `MDLocation`),
since a couple of these use cases need to handle broken code.

llvm-svn: 233585
2015-03-30 19:40:05 +00:00
David Blaikie
84396f6ee6 BitcodeWriter: Refactor common computation of bits required for a type index.
Suggested by Duncan. Happy to bikeshed the name, cache the result, etc.

llvm-svn: 230410
2015-02-25 00:51:52 +00:00
Duncan P. N. Exon Smith
55694c075d IR: Assembly and bitcode for GenericDebugNode
llvm-svn: 228041
2015-02-03 21:54:14 +00:00
Duncan P. N. Exon Smith
439bf9404e IR: Split out DebugInfoMetadata.h, NFC
Move debug-info-centred `Metadata` subclasses into their own
header/source file.  A couple of private template functions are needed
from both `Metadata.cpp` and `DebugInfoMetadata.cpp`, so I've moved them
to `lib/IR/MetadataImpl.h`.

llvm-svn: 227835
2015-02-02 18:53:21 +00:00
Duncan P. N. Exon Smith
fc8503a473 Bitcode: Add ValueEnumerator::getMetadataOrNullID(), NFC
llvm-svn: 226533
2015-01-20 01:00:23 +00:00
Duncan P. N. Exon Smith
85eaac222d AsmParser/Bitcode: Add support for MDLocation
This adds assembly and bitcode support for `MDLocation`.  The assembly
side is rather big, since this is the first `MDNode` subclass (that
isn't `MDTuple`).  Part of PR21433.

(If you're wondering where the mountains of testcase updates are, we
don't need them until I update `DILocation` and `DebugLoc` to actually
use this class.)

llvm-svn: 225830
2015-01-13 21:10:44 +00:00
Duncan P. N. Exon Smith
f9e3ad202e Bitcode: Simplify emission of METADATA_BLOCK
Refactor logic so that we know up-front whether to open a block and
whether we need an MDString abbreviation.

This is almost NFC, but will start emitting `MDString` abbreviations
when the first record is not an `MDString`.

llvm-svn: 225712
2015-01-12 22:30:34 +00:00
Nick Lewycky
224bcdd295 Make ValueEnumerator::print use OS for metadata too. Noticed by inspection.
llvm-svn: 224404
2014-12-17 01:52:08 +00:00
Duncan P. N. Exon Smith
972205b3d9 Bitcode: Add METADATA_NODE and METADATA_VALUE
This reflects the typelessness of `Metadata` in the bitcode format,
removing types from all metadata operands.

`METADATA_VALUE` represents a `ValueAsMetadata`, and always has two
fields: the type and the value.

`METADATA_NODE` represents an `MDNode`, and unlike `METADATA_OLD_NODE`,
doesn't store types.  It stores operands at their ID+1 so that `0` can
reference `nullptr` operands.

Part of PR21532.

llvm-svn: 224073
2014-12-11 23:02:24 +00:00
Duncan P. N. Exon Smith
3d57886267 IR: Split Metadata from Value
Split `Metadata` away from the `Value` class hierarchy, as part of
PR21532.  Assembly and bitcode changes are in the wings, but this is the
bulk of the change for the IR C++ API.

I have a follow-up patch prepared for `clang`.  If this breaks other
sub-projects, I apologize in advance :(.  Help me compile it on Darwin
I'll try to fix it.  FWIW, the errors should be easy to fix, so it may
be simpler to just fix it yourself.

This breaks the build for all metadata-related code that's out-of-tree.
Rest assured the transition is mechanical and the compiler should catch
almost all of the problems.

Here's a quick guide for updating your code:

  - `Metadata` is the root of a class hierarchy with three main classes:
    `MDNode`, `MDString`, and `ValueAsMetadata`.  It is distinct from
    the `Value` class hierarchy.  It is typeless -- i.e., instances do
    *not* have a `Type`.

  - `MDNode`'s operands are all `Metadata *` (instead of `Value *`).

  - `TrackingVH<MDNode>` and `WeakVH` referring to metadata can be
    replaced with `TrackingMDNodeRef` and `TrackingMDRef`, respectively.

    If you're referring solely to resolved `MDNode`s -- post graph
    construction -- just use `MDNode*`.

  - `MDNode` (and the rest of `Metadata`) have only limited support for
    `replaceAllUsesWith()`.

    As long as an `MDNode` is pointing at a forward declaration -- the
    result of `MDNode::getTemporary()` -- it maintains a side map of its
    uses and can RAUW itself.  Once the forward declarations are fully
    resolved RAUW support is dropped on the ground.  This means that
    uniquing collisions on changing operands cause nodes to become
    "distinct".  (This already happened fairly commonly, whenever an
    operand went to null.)

    If you're constructing complex (non self-reference) `MDNode` cycles,
    you need to call `MDNode::resolveCycles()` on each node (or on a
    top-level node that somehow references all of the nodes).  Also,
    don't do that.  Metadata cycles (and the RAUW machinery needed to
    construct them) are expensive.

  - An `MDNode` can only refer to a `Constant` through a bridge called
    `ConstantAsMetadata` (one of the subclasses of `ValueAsMetadata`).

    As a side effect, accessing an operand of an `MDNode` that is known
    to be, e.g., `ConstantInt`, takes three steps: first, cast from
    `Metadata` to `ConstantAsMetadata`; second, extract the `Constant`;
    third, cast down to `ConstantInt`.

    The eventual goal is to introduce `MDInt`/`MDFloat`/etc. and have
    metadata schema owners transition away from using `Constant`s when
    the type isn't important (and they don't care about referring to
    `GlobalValue`s).

    In the meantime, I've added transitional API to the `mdconst`
    namespace that matches semantics with the old code, in order to
    avoid adding the error-prone three-step equivalent to every call
    site.  If your old code was:

        MDNode *N = foo();
        bar(isa             <ConstantInt>(N->getOperand(0)));
        baz(cast            <ConstantInt>(N->getOperand(1)));
        bak(cast_or_null    <ConstantInt>(N->getOperand(2)));
        bat(dyn_cast        <ConstantInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<ConstantInt>(N->getOperand(4)));

    you can trivially match its semantics with:

        MDNode *N = foo();
        bar(mdconst::hasa               <ConstantInt>(N->getOperand(0)));
        baz(mdconst::extract            <ConstantInt>(N->getOperand(1)));
        bak(mdconst::extract_or_null    <ConstantInt>(N->getOperand(2)));
        bat(mdconst::dyn_extract        <ConstantInt>(N->getOperand(3)));
        bay(mdconst::dyn_extract_or_null<ConstantInt>(N->getOperand(4)));

    and when you transition your metadata schema to `MDInt`:

        MDNode *N = foo();
        bar(isa             <MDInt>(N->getOperand(0)));
        baz(cast            <MDInt>(N->getOperand(1)));
        bak(cast_or_null    <MDInt>(N->getOperand(2)));
        bat(dyn_cast        <MDInt>(N->getOperand(3)));
        bay(dyn_cast_or_null<MDInt>(N->getOperand(4)));

  - A `CallInst` -- specifically, intrinsic instructions -- can refer to
    metadata through a bridge called `MetadataAsValue`.  This is a
    subclass of `Value` where `getType()->isMetadataTy()`.

    `MetadataAsValue` is the *only* class that can legally refer to a
    `LocalAsMetadata`, which is a bridged form of non-`Constant` values
    like `Argument` and `Instruction`.  It can also refer to any other
    `Metadata` subclass.

(I'll break all your testcases in a follow-up commit, when I propagate
this change to assembly.)

llvm-svn: 223802
2014-12-09 18:38:53 +00:00
Peter Collingbourne
837799f13b Prologue support
Patch by Ben Gamari!

This redefines the `prefix` attribute introduced previously and
introduces a `prologue` attribute.  There are a two primary usecases
that these attributes aim to serve,

  1. Function prologue sigils

  2. Function hot-patching: Enable the user to insert `nop` operations
     at the beginning of the function which can later be safely replaced
     with a call to some instrumentation facility

  3. Runtime metadata: Allow a compiler to insert data for use by the
     runtime during execution. GHC is one example of a compiler that
     needs this functionality for its tables-next-to-code functionality.

Previously `prefix` served cases (1) and (2) quite well by allowing the user
to introduce arbitrary data at the entrypoint but before the function
body. Case (3), however, was poorly handled by this approach as it
required that prefix data was valid executable code.

Here we redefine the notion of prefix data to instead be data which
occurs immediately before the function entrypoint (i.e. the symbol
address). Since prefix data now occurs before the function entrypoint,
there is no need for the data to be valid code.

The previous notion of prefix data now goes under the name "prologue
data" to emphasize its duality with the function epilogue.

The intention here is to handle cases (1) and (2) with prologue data and
case (3) with prefix data.

References
----------

This idea arose out of discussions[1] with Reid Kleckner in response to a
proposal to introduce the notion of symbol offsets to enable handling of
case (3).

[1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073235.html

Test Plan: testsuite

Differential Revision: http://reviews.llvm.org/D6454

llvm-svn: 223189
2014-12-03 02:08:38 +00:00
Rafael Espindola
5cee6ee598 Add and use Type::subtypes. NFC.
llvm-svn: 222682
2014-11-24 20:44:36 +00:00
Rafael Espindola
78bd4d36bf Pass a reference to ValueEnumerator.
NFC. This will just make it easier to use std::unique_ptr in a caller.

llvm-svn: 222170
2014-11-17 20:06:27 +00:00
Duncan P. N. Exon Smith
8770505e4e Revert "IR: MDNode => Value"
Instead, we're going to separate metadata from the Value hierarchy.  See
PR21532.

This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.

llvm-svn: 221711
2014-11-11 21:30:22 +00:00
Duncan P. N. Exon Smith
8f49c8202f IR: MDNode => Value: Instruction::getAllMetadataOtherThanDebugLoc()
Change `Instruction::getAllMetadataOtherThanDebugLoc()` from a vector of
`MDNode` to one of `Value`.  Part of PR21433.

llvm-svn: 221167
2014-11-03 18:13:57 +00:00
Duncan P. N. Exon Smith
38802ea9da IR: Reorder metadata bitcode serialization, NFC
Enumerate `MDNode`'s operands *before* the node itself, so that the
reader requires less RAUW.  Although this will cause different code
paths to be hit in the reader, this should effectively be no
functionality change.

llvm-svn: 220340
2014-10-21 22:27:47 +00:00
Duncan P. N. Exon Smith
ac50c13623 IR: Remove dead code in metadata bitcode writing, NFC
No one cares how many uses each metadata value has, so don't bother
counting.

llvm-svn: 220337
2014-10-21 22:13:34 +00:00
Duncan P. N. Exon Smith
ad02adcc91 UseListOrder: Handle self-users
Correctly sort self-users (such as PHI nodes).  I added a targeted test
in `test/Bitcode/use-list-order.ll` and the final missing RUN line to
tests in `test/Assembly`.

This is part of PR5680.

llvm-svn: 214417
2014-07-31 18:33:12 +00:00
Duncan P. N. Exon Smith
fba0626873 UseListOrder: Don't give constant IDs to GlobalValues
Since initializers of GlobalValues are being assigned IDs before
GlobalValues themselves, explicitly exclude GlobalValues from the
constant pool.  Added targeted test in `test/Bitcode/use-list-order.ll`
and added two more RUN lines in `test/Assembly`.

This is part of PR5680.

llvm-svn: 214368
2014-07-31 00:13:28 +00:00
Duncan P. N. Exon Smith
789d5bf211 UseListOrder: Visit global values
When predicting use-list order, we visit functions in reverse order
followed by `GlobalValue`s and write out use-lists at the first
opportunity.  In the reader, this will translate to *after* the last use
has been added.

For this to work, we actually need to descend into `GlobalValue`s.
Added a targeted test in `use-list-order.ll` and `RUN` lines to the
newly passing tests in `test/Bitcode`.

There are two remaining failures in `test/Bitcode`:

  - blockaddress.ll: I haven't thought through how to model the way
    block addresses change the order of use-lists (or how to work around
    it).

  - metadata-2.ll: There's an old-style `@llvm.used` global array here
    that I suspect the .ll parser isn't upgrading properly.  When it
    round-trips through bitcode, the .bc reader *does* upgrade it, so
    the extra variable (`i8* null`) has an extra use, and the shuffle
    vector doesn't match.

    I think the fix is to upgrade old-style global arrays (or reject
    them?) in the .ll parser.

This is part of PR5680.

llvm-svn: 214321
2014-07-30 17:51:09 +00:00
Duncan P. N. Exon Smith
1d7b0f97dd Reapply "UseListOrder: Order GlobalValue uses after initializers"
This reverts commit r214249, reapplying r214242 and r214243, now that
r214270 has fixed the UB.

llvm-svn: 214271
2014-07-30 01:22:16 +00:00
Duncan P. N. Exon Smith
5d1b1e64b5 UseListOrder: Fix undefined behaviour
This commit fixes undefined behaviour that caused the revert in r214249.

The problem was two unsequenced operations on a `DenseMap<>`, giving
different behaviour in GCC and Clang.  This:

    DenseMap<T*, unsigned> DM;
    for (auto &X : ...)
      DM[&X] = DM.size() + 1;

should have been:

    DenseMap<T*, unsigned> DM;
    for (auto &X : ...) {
      unsigned Size = DM.size();
      DM[&X] = Size + 1;
    }

Until r214242, this difference between compilers didn't matter.  In
r214242, `OrderMap::LastGlobalValueID` was introduced and compared
against IDs, which in GCC were off-by-one my expectations.

llvm-svn: 214270
2014-07-30 01:20:26 +00:00
Duncan P. N. Exon Smith
cc8a88fa18 Revert "UseListOrder: Order GlobalValue uses after initializers"
This reverts commits r214242 and r214243 while I investigate buildbot
failures [1][2][3].  I can't reproduce these failures locally, so if
anyone can see what I've done wrong, I'd appreciate a note.

[1]: http://lab.llvm.org:8011/builders/llvm-hexagon-elf/builds/9840
[2]: http://lab.llvm.org:8011/builders/clang-hexagon-elf/builds/14981
[3]: http://bb.pgr.jp/builders/cmake-llvm-x86_64-linux/builds/15191

llvm-svn: 214249
2014-07-29 23:31:11 +00:00
Duncan P. N. Exon Smith
cdab8367f8 UseListOrder: Order GlobalValue uses after initializers
To avoid unnecessary forward references, the reader doesn't process
initializers of `GlobalValue`s until after the constant pool has been
processed, and then in reverse order.  Model this when predicting
use-list order.  This gets two more Bitcode tests passing with
`llvm-uselistorder`.

Part of PR5680.

llvm-svn: 214242
2014-07-29 23:06:14 +00:00
Duncan P. N. Exon Smith
589a519a8a UseListOrder: Create a struct around OrderMap, NFC
llvm-svn: 214241
2014-07-29 23:03:40 +00:00