Commit Graph

3178 Commits

Author SHA1 Message Date
Scott Linder 16c7bdaf32 [DebugInfo] Support DWARF v5 source code embedding extension
In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. In this extension a content type is added,
DW_LNCT_LLVM_source, which contains the embedded source code of the file.

Add new optional attribute for !DIFile IR metadata called source which contains
source text. Use this to output the source to the DWARF line table of code
objects. Analogously extend METADATA_FILE in Bitcode and .file directive in ASM
to support optional source.

Teach llvm-dwarfdump and llvm-objdump about the new values. Update the output
format of llvm-dwarfdump to make room for the new attribute on file_names
entries, and support embedded sources for the -source option in llvm-objdump.

Differential Revision: https://reviews.llvm.org/D42765

llvm-svn: 325970
2018-02-23 23:01:06 +00:00
Sriraman Tallam 609f8c013c Intrinsics calls should avoid the PLT when "RtLibUseGOT" metadata is present.
Differential Revision: https://reviews.llvm.org/D42216

llvm-svn: 325962
2018-02-23 21:32:06 +00:00
Sanjay Patel d32104e1b2 [InstCombine] allow fmul-sqrt folds with less than full -ffast-math
Also, add a Builder method for intrinsics to reduce code duplication for clients.

llvm-svn: 325960
2018-02-23 21:16:12 +00:00
Serge Guelton 1fb81bcb9b Syndicate duplicate code between CallInst and InvokeInst
NFC intended, syndicate common code to a parametric base class. Part of the original problem is that InvokeInst is a TerminatorInst, unlike CallInst. the problem is solved by introducing a parametrized class paramtertized by its base.

Differential Revision: https://reviews.llvm.org/D40727

llvm-svn: 325778
2018-02-22 13:30:32 +00:00
Sanjay Patel 90f4c8ec29 [InstCombine] fold fdiv with non-splat divisor to fmul: X/C --> X * (1/C)
llvm-svn: 325590
2018-02-20 16:08:15 +00:00
Craig Topper 9256ac1a58 [X86] Add 512-bit unmasked pmulhrsw/pmulhw/pmulhuw intrinsics. Remove and auto upgrade 128/256/512 bit masked pmulhrsw/pmulhw/pmulhuw intrinsics.
The 128 and 256 bit versions were already not used by clang. This adds an equivalent unmasked 512 bit version. Then autoupgrades all sizes to use unmasked intrinsics plus select.

llvm-svn: 325559
2018-02-20 07:28:14 +00:00
Charles Saternos b040fcc693 [ThinLTO] Add GraphTraits for FunctionSummaries
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.

Third attempt - moved function from lambda to static function due to build failures.

llvm-svn: 325506
2018-02-19 15:14:50 +00:00
Dylan McKay ced2fe68f3 Add default address space for functions to the data layout (1/3)
Summary:
This adds initial support for letting targets specify which address
spaces their functions should reside in by default.

If a function is created by a frontend, it will get the default address space specified in the DataLayout, unless the frontend explicitly uses a more general `llvm::Function` constructor. Function address spaces will become a part of the bitcode and textual IR forms, as we do not have access to a data layout whilst parsing LL.

It will be possible to write IR that explicitly has `addrspace(n)` on a function. In this case, the function will reside in the specified space, ignoring the default in the DL.

This is the first step towards placing functions into the correct
address space for Harvard architectures.

Full patchset
* Add program address space to data layout D37052
* Require address space to be specified when creating functions D37054
* [clang] Require address space to be specified when creating functions D37057

Reviewers: pcc, arsenm, kparzysz, hfinkel, theraven

Reviewed By: theraven

Subscribers: arichardson, simoncook, rengolin, wdng, uabelho, bjope, asb, llvm-commits

Differential Revision: https://reviews.llvm.org/D37052

llvm-svn: 325479
2018-02-19 09:56:22 +00:00
Simon Pilgrim 0efed32577 Revert: [llvm] r325448 - [ThinLTO] Add GraphTraits for FunctionSummaries
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.

Second attempt, since last patch caused stage2 build to fail (now using function_ref rather than std::function).

Reverted due to buildbot failures

llvm-svn: 325454
2018-02-18 00:01:36 +00:00
Charles Saternos 35878ee7a4 [ThinLTO] Add GraphTraits for FunctionSummaries
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.

Second attempt, since last patch caused stage2 build to fail (now using function_ref rather than std::function).

llvm-svn: 325448
2018-02-17 21:39:24 +00:00
Sanjay Patel 08868e494e [Constant] add floating-point helpers for normal/finite-nz; NFC
...and delete the equivalent local functiona from InstCombine.

These might be useful to other InstCombine files or other passes
and makes FP queries more similar to integer constant queries.

llvm-svn: 325398
2018-02-16 22:32:54 +00:00
Brian M. Rzycki f1a7df5ef2 [JumpThreading] PR36133 enable/disable DominatorTree for LVI analysis
Summary:
The LazyValueInfo pass caches a copy of the DominatorTree when available.
Whenever there are pending DominatorTree updates within JumpThreading's
DeferredDominance object we cannot use the cached DT for LVI analysis.
This commit adds the new methods enableDT() and disableDT() to LVI.
JumpThreading also sets the appropriate usage model before calling LVI
analysis methods.

Fixes https://bugs.llvm.org/show_bug.cgi?id=36133

Reviewers: sebpop, dberlin, kuhar

Reviewed by: sebpop, kuhar

Subscribers: uabelho, llvm-commits, aprantl, hiraditya, a.elovikov

Differential Revision: https://reviews.llvm.org/D42717

llvm-svn: 325356
2018-02-16 16:35:17 +00:00
Sanjay Patel 6a0f667077 [InstCombine] allow X / C -> X * (1.0/C) for vector splat FP constants
llvm-svn: 325237
2018-02-15 13:55:52 +00:00
Petar Jovanovic 1768957c82 [Utils] Salvage the debug info of DCE'ed 'and' instructions
Preserve debug info from a dead 'and' instruction with a constant.

Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D43163

llvm-svn: 325119
2018-02-14 13:10:35 +00:00
Elena Demikhovsky 945b7e5aa6 Adding a width of the GEP index to the Data Layout.
Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.

Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html

I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.

Differential Revision: https://reviews.llvm.org/D42123

llvm-svn: 325102
2018-02-14 06:58:08 +00:00
Ivan A. Kosarev 4a381b444e [IR] Fix creating mutable versions of TBAA access tags
Due to a typo in D41565, mutable TBAA tags created with
createMutableTBAAAccessTag() lose their base types. This patch
fixes that typo and updates tests respectively.

Differential Revision: https://reviews.llvm.org/D42364

llvm-svn: 325008
2018-02-13 14:44:25 +00:00
Vedant Kumar 4011c26cc7 [Utils] Salvage debug info of DCE'ed mul/sdiv/srem instructions
Here are the number of additional debug values salvaged in a stage2
build of clang:

  63 SALVAGE: MUL
  1250 SALVAGE: SDIV

(No values were salvaged from `srem` instructions in this experiment,
but it's a simple case to handle so we might as well.)

llvm-svn: 324976
2018-02-13 01:09:52 +00:00
Vedant Kumar 31ec356a48 [Utils] Salvage debug info of DCE'ed shl/lhsr/ashr instructions
Here are the number of additional debug values salvaged in a stage2
build of clang:

  1912 SALVAGE: ASHR
   405 SALVAGE: LSHR
   249 SALVAGE: SHL

llvm-svn: 324975
2018-02-13 01:09:49 +00:00
Vedant Kumar 96b7dc041b [Utils] Salvage the debug info of DCE'ed 'xor' instructions
This salvages 259 debug values in a stage2 build of clang.

Differential Revision: https://reviews.llvm.org/D43207

llvm-svn: 324973
2018-02-13 01:09:46 +00:00
Craig Topper 8d19c6fba2 [X86] Reverse the operand order of the autoupgrade of the kunpack builtins.
The second operand needs to be in the lower bits of the concatenation. This matches llvm 5.0, gcc, and icc behavior.

Fixes PR36360.

llvm-svn: 324953
2018-02-12 22:38:34 +00:00
Volodymyr Sapsai 2ad768bb13 Revert "[ThinLTO] Add GraphTraits for FunctionSummaries"
It caused assertion failure
Assertion failed: (!DD.IsLambda && !MergeDD.IsLambda && "faked up lambda definition?"), function MergeDefinitionData, file /Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/lib/Serialization/ASTReaderDecl.cpp, line 1675.

on the second stage build bots.

llvm-svn: 324932
2018-02-12 20:43:31 +00:00
Scott Linder 7160384d40 [DebugInfo] Unify ChecksumKind and Checksum value in DIFile
Rather than encode the absence of a checksum with a Kind variant, instead put
both the kind and value in a struct and wrap it in an Optional.

Differential Revision: http://reviews.llvm.org/D43043

llvm-svn: 324928
2018-02-12 19:45:54 +00:00
Momchil Velikov 08dc66eff0 Re-commit r324489: [DebugInfo] Improvements to representation of enumeration types (PR36168)
Differential Revision: https://reviews.llvm.org/D42734

llvm-svn: 324899
2018-02-12 16:10:09 +00:00
Charles Saternos d3e7d19f59 [ThinLTO] Add GraphTraits for FunctionSummaries
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.

llvm-svn: 324854
2018-02-11 22:06:20 +00:00
Craig Topper 4dccffc84a [X86] Change signatures of avx512 packed fp compare intrinsics to return a vXi1 mask type to be closer to an fcmp.
Summary:
This patch changes the signature of the avx512 packed fp compare intrinsics to return a vXi1 vector and no longer take a mask as input. The casts to scalar type will now need to be explicit in the IR. The masking node will now be an explicit and in the IR.

This makes the intrinsic look much more similar to an fcmp instruction that we wish we could use for these but can't. We already use icmp instructions for integer compares.

Previously the lowering step of isel would turn the intrinsic into an X86 specific ISD node and a emit the masking nodes as well as some bitcasts. This means DAG combines can't see the vXi1 type until somewhat late, making it more difficult to combine out gpr<->mask transition sequences. By exposing the vXi1 type explicitly in the IR and initial SelectionDAG we give earlier DAG combines and even InstCombine the chance to see it and optimize it.

This should make any issues with gpr<->mask sequences the same between integer and fp. Meaning we only have to fix them once.

Reviewers: spatel, delena, RKSimon, zvi

Reviewed By: RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D43137

llvm-svn: 324827
2018-02-10 23:33:55 +00:00
Vedant Kumar 04386d8e3d [Utils] Salvage debug info from dead 'or' instructions
Extend salvageDebugInfo to preserve the debug info from a dead 'or'
with a constant.

Patch by Ismail Badawi!

Differential Revision: https://reviews.llvm.org/D43129

llvm-svn: 324764
2018-02-09 19:19:55 +00:00
Serguei Katkov 3cb4c34a4e Rename and move utility function getLatchPredicateForGuard. NFC.
Rename getLatchPredicateForGuard to more common name
getFlippedStrictnessPredicate and move it to ICmpInst class.

llvm-svn: 324717
2018-02-09 07:59:07 +00:00
Craig Topper dccf72b583 [X86] Remove kortest intrinsics and replace with native IR.
llvm-svn: 324646
2018-02-08 20:16:06 +00:00
Vedant Kumar 4347227437 Use ranged for loops in TypeFinder.cpp, NFC
llvm-svn: 324628
2018-02-08 18:02:27 +00:00
Momchil Velikov 74906a467c Revert "[DebugInfo] Improvements to representation of enumeration types (PR36168)"
Revert commit r324489, it broke LLDB tests.

llvm-svn: 324511
2018-02-07 20:28:47 +00:00
Momchil Velikov c502027efd [DebugInfo] Improvements to representation of enumeration types (PR36168)
This patch is the LLVM part of fixing the issues, described in
https://bugs.llvm.org/show_bug.cgi?id=36168

* The representation of enumerator values in the debug info metadata now
  contains a boolean flag isUnsigned, which determines how the bits of
  the value are interpreted.
* The DW_TAG_enumeration type DIE now always (for DWARF version >= 3)
  includes a DW_AT_type attribute, which refers to the underlying
  integer type, as suggested in DWARFv4 (5.7 Enumeration Type Entries).
* The debug info metadata for enumeration type contains (in flags)
  indication whether this is a C++11 "fixed enum".
* For C++11 enumeration with a fixed underlying type, the DIE also
  includes the DW_AT_enum_class attribute (for DWARF version >= 4).
* Encoding of enumerator constants uses DW_FORM_sdata for signed values
  and DW_FORM_udata for unsigned values, as suggested by DWARFv4 (7.5.4
  Attribute Encodings).

The changes should be backwards compatible:

* the isUnsigned attribute is optional and defaults to false.
* if the underlying type for the enumeration is not available, the
  enumerator values are considered signed.
* the FixedEnum flag defaults to clear.
* the bitcode format for DIEnumerator stores the unsigned flag bit #1 of
  the first record element, so the format does not change and the zero
  previously stored there is consistent with the false default for
  IsUnsigned.

Differential Revision: https://reviews.llvm.org/D42734

llvm-svn: 324489
2018-02-07 16:46:33 +00:00
Max Kazantsev b299ade2c5 Re-enable "[SCEV] Make isLoopEntryGuardedByCond a bit smarter"
The failures happened because of assert which was overconfident about
SCEV's proving capabilities and is generally not valid.

Differential Revision: https://reviews.llvm.org/D42835

llvm-svn: 324473
2018-02-07 11:16:29 +00:00
Serguei Katkov 69246ca787 Revert [SCEV] Make isLoopEntryGuardedByCond a bit smarter
Revert rL324453 commit which causes buildbot failures.

Differential Revision: https://reviews.llvm.org/D42835

llvm-svn: 324462
2018-02-07 09:10:08 +00:00
Max Kazantsev dd5ee6f5d9 [SCEV] Make isLoopEntryGuardedByCond a bit smarter
Sometimes `isLoopEntryGuardedByCond` cannot prove predicate `a > b` directly.
But it is a common situation when `a >= b` is known from ranges and `a != b` is
known from a dominating condition. Thia patch teaches SCEV to sum these facts
together and prove strict comparison via non-strict one.

Differential Revision: https://reviews.llvm.org/D42835

llvm-svn: 324453
2018-02-07 07:56:26 +00:00
Adrian Prantl 8c59921ca3 Add DWARF for discriminated unions
n Rust, an enum that carries data in the variants is, essentially, a
discriminated union. Furthermore, the Rust compiler will perform
space optimizations on such enums in some situations. Previously,
DWARF for these constructs was emitted using a hack (a magic field
name); but this approach stopped working when more space optimizations
were added in https://github.com/rust-lang/rust/pull/45225.

This patch changes LLVM to allow discriminated unions to be
represented in DWARF. It adds createDiscriminatedUnionType and
createDiscriminatedMemberType to DIBuilder and then arranges for this
to be emitted using DWARF's DW_TAG_variant_part and DW_TAG_variant.

Note that DWARF requires that a discriminated union be represented as
a structure with a variant part. However, as Rust only needs to emit
pure discriminated unions, this is what I chose to expose on
DIBuilder.

Patch by Tom Tromey!

Differential Revision: https://reviews.llvm.org/D42082

llvm-svn: 324426
2018-02-06 23:45:59 +00:00
Peter Collingbourne b4edfb9af9 LTO: Include dso-local bit in ThinLTO cache key.
Differential Revision: https://reviews.llvm.org/D42713

llvm-svn: 324253
2018-02-05 17:17:51 +00:00
Craig Topper 071ad9c6e0 [X86] Remove and autoupgrade kand/kandn/kor/kxor/kxnor/knot intrinsics.
Clang already stopped using these a couple months ago.

The test cases aren't great as there is nothing forcing the operations to stay in k-registers so some of them moved back to scalar ops due to the bitcasts being moved around.

llvm-svn: 324177
2018-02-03 20:18:25 +00:00
Robert Widmann 490a5808cd [LLVM-C] Add Accessors For A Module's Source File Name
Summary: Also unblocks some cleanup in the echo-test.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: harlanhaskins, llvm-commits

Differential Revision: https://reviews.llvm.org/D42618

llvm-svn: 323819
2018-01-30 21:34:29 +00:00
Petar Jovanovic 9208e8fbf6 [DeadArgumentElimination] Preserve llvm.dbg.values's first argument
When removing return value Dead Argument Elimination pass clobbers first
llvm.dbg.value’s argument for live arguments of that function by replacing
it with nullptr. In the next pass it will be deleted, so debug location
about those arguments are lost. This change fixes it.

Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D42541

llvm-svn: 323784
2018-01-30 16:42:04 +00:00
Daniel Neilson 551a4d6557 Add IRBuilder API to create memcpy/memmove calls with differing source and dest alignments
Summary:
  This change is step two in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. Steps:

Step 1) Remove alignment parameter and create alignment parameter attributes for
   memcpy/memmove/memset. ( rL322965 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
   source and dest alignments.
Step 3) Update Clang to use the new IRBuilder API.
Step 4) Update Polly to use the new IRBuilder API.
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
        and those that use use MemIntrinsicInst::[get|set]Alignment() to use
        getDestAlignment() and getSourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
        MemIntrinsicInst::[get|set]Alignment() methods.

Reference
   http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.html
   http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

llvm-svn: 323597
2018-01-27 17:59:10 +00:00
Benjamin Kramer d15b2898d3 [Support] Move PrintEscapedString into the library its declaration is in
llvm-svn: 323558
2018-01-26 20:21:02 +00:00
Sander de Smalen fdf40917d9 [Metadata] Extend 'count' field of DISubrange to take a metadata node
Summary:
This patch extends the DISubrange 'count' field to take either a
(signed) constant integer value or a reference to a DILocalVariable
or DIGlobalVariable.

This is patch [1/3] in a series to extend LLVM's DISubrange Metadata
node to support debugging of C99 variable length arrays and vectors with
runtime length like the Scalable Vector Extension for AArch64. It is
also a first step towards representing more complex cases like arrays
in Fortran.

Reviewers: echristo, pcc, aprantl, dexonsmith, clayborg, kristof.beyls, dblaikie

Reviewed By: aprantl

Subscribers: rnk, probinson, fhahn, aemerson, rengolin, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D41695

llvm-svn: 323313
2018-01-24 09:56:07 +00:00
Jakub Kuderski ffb4fb7f6f [Dominators] Introduce DomTree verification levels
Summary:
Currently, there are 2 ways to verify a DomTree:
* `DT.verify()` -- runs full tree verification and checks all the properties and gives a reason why the tree is incorrect. This is run by when EXPENSIVE_CHECKS are enabled or when `-verify-dom-info` flag is set.
* `DT.verifyDominatorTree()` -- constructs a fresh tree and compares it against the old one. This does not check any other tree properties (DFS number, levels), nor ensures that the construction algorithm is correct. Used by some passes inside assertions.

This patch introduces DomTree verification levels, that try to close the gape between the two ways of checking trees by introducing 3 verification levels:
- Full -- checks all properties, but can be slow (O(N^3)). Used when manually requested (e.g. `assert(DT.verify())`) or when  `-verify-dom-info` is set.
- Basic -- checks all properties except the sibling property, and compares the current tree with a freshly constructed one instead. This should catch almost all errors, but does not guarantee that the construction algorithm is correct. Used when EXPENSIVE checks are enabled.
- Fast -- checks only basic properties (reachablility, dfs numbers, levels, roots), and compares with a fresh tree. This is meant to replace the legacy `DT.verifyDominatorTree()` and in my tests doesn't cause any noticeable performance impact even in the most pessimistic examples.

When used to verify dom tree wrapper pass analysis on sqlite3, the 3 new levels make `opt -O3` take the following amount of time on my machine:
- no verification: 8.3s
- `DT.verify(VerificationLevel::Fast)`: 10.1s
- `DT.verify(VerificationLevel::Basic)`: 44.8s
- `DT.verify(VerificationLevel::Full)`: 1m 46.2s
(and the previous `DT.verifyDominatorTree()` is within the noise of the Fast level)

This patch makes `DT.verifyDominatorTree()` pick between the 3 verification levels depending on EXPENSIVE_CHECKS and `-verify-dom-info`.

Reviewers: dberlin, brzycki, davide, grosser, dmgreen

Reviewed By: dberlin, brzycki

Subscribers: MatzeB, llvm-commits

Differential Revision: https://reviews.llvm.org/D42337

llvm-svn: 323298
2018-01-24 02:40:35 +00:00
Yaxun Liu d0820433b1 Verifier: fix bug treating debug info issue as non-debug info issue
Normally when llvm-as sees only debug info errors in LLVM assembly, it simply
drops the debug info and outputs a valid LLVM bitcode and returns 0.

There is a bug in LLVM verifier which incorrectly treats a debug info error
as non-debug info error, which causes llvm-as returns 1 even though llvm-as
can drop the invalid debug info and outputs a valid LLVM bitcode.

This patch fixes that.

Differential Revision: https://reviews.llvm.org/D42391

llvm-svn: 323216
2018-01-23 16:11:15 +00:00
Ashutosh Nema 007b425b77 This change add's optimization remark in LoopVersioning LICM pass.
Summary:
This patch is adding remark messages to the LoopVersioning LICM pass, 
which will be useful for optimization remark emitter (ORE) infrastructure.

Patch by: Deepak Porwal

Reviewers: anemet, ashutosh.nema, eastig

Subscribers: eastig, vivekvpandya, fhahn, llvm-commits
llvm-svn: 323183
2018-01-23 09:47:28 +00:00
Eugene Leviant 28d8a49f42 [ThinLTO] Re-commit of dot dumper after test fix
llvm-svn: 323116
2018-01-22 13:35:40 +00:00
Eugene Leviant 72b9bdb71a Temporarily revert r323062 to investigate buildbot failures
llvm-svn: 323065
2018-01-21 10:22:19 +00:00
Eugene Leviant 453c976a63 [ThinLTO] Implement summary visualizer
Differential revision: https://reviews.llvm.org/D41297

llvm-svn: 323062
2018-01-21 07:27:32 +00:00
Saleem Abdulrasool 99f479abcf CodeGen: handle llvm.used properly for COFF
`llvm.used` contains a list of pointers to named values which the
compiler, assembler, and linker are required to treat as if there is a
reference that they cannot see.  Ensure that the symbols are preserved
by adding an explicit `-include` reference to the linker command.

llvm-svn: 323017
2018-01-20 00:28:02 +00:00
Jessica Paquette a499c3c29d Add optional DICompileUnit to DIBuilder + make outliner debug info use it
Previously, the DIBuilder didn't expose functionality to set its compile unit
in any other way than calling createCompileUnit. This meant that the outliner,
which creates new functions, had to create a new compile unit for its debug
info.

This commit adds an optional parameter in the DIBuilder's constructor which
lets you set its CU at construction.

It also changes the MachineOutliner so that it keeps track of the DISubprograms
for each outlined sequence. If debugging information is requested, then it
uses one of the outlined sequence's DISubprograms to grab a CU. It then uses
that CU to construct the DISubprogram for the new outlined function.

The test has also been updated to reflect this change.

See https://reviews.llvm.org/D42254 for more information. Also see the e-mail
discussion on D42254 in llvm-commits for more context.

llvm-svn: 322992
2018-01-19 21:21:49 +00:00