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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
- 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
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
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
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
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
If TBAA is on an intrinsic and it gets upgraded, it'll delete the call
instruction that we collected in a vector. Even if we were to use
WeakVH, it'll drop the TBAA and we'll hit the assert on the upgrade
path.
r263673 gave a shot to make sure the TBAA upgrade happens before
intrinsics upgrade, but failed to account for all cases.
Instead of collecting instructions in a vector, this patch makes it
just upgrade the TBAA on the fly, because metadata are always
already loaded at this point.
Differential Revision: https://reviews.llvm.org/D24533
llvm-svn: 281549
This patch reverses the edge from DIGlobalVariable to GlobalVariable.
This will allow us to more easily preserve debug info metadata when
manipulating global variables.
Fixes PR30362. A program for upgrading test cases is attached to that
bug.
Differential Revision: http://reviews.llvm.org/D20147
llvm-svn: 281284
Use ADT/BitmaskEnum for DINode::DIFlags for the following purposes:
Get rid of unsigned int for flags to avoid problems on platforms with sizeof(int) < 4
Flags are now strongly typed
Patch by: Victor Leschuk <vleschuk@gmail.com>
Differential Revision: https://reviews.llvm.org/D23766
llvm-svn: 280700
Use ADT/BitmaskEnum for DINode::DIFlags for the following purposes:
* Get rid of unsigned int for flags to avoid problems on platforms with sizeof(int) < 4
* Flags are now strongly typed
Patch by: Victor Leschuk <vleschuk@gmail.com>
Differential Revision: https://reviews.llvm.org/D23766
llvm-svn: 280686
In cases where .dwo/.dwp files are guaranteed to be available, skipping
the extra online (in the .o file) inline info can save a substantial
amount of space - see the original r221306 for more details there.
llvm-svn: 279650
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.
llvm-svn: 278902
The auto-upgrade path could be called before the VST (global
names) was fully parsed, and thus intrinsic names were not
available and the autoupgrade logic could not operate.
Fix link failures with ThinLTO.
This is a recommit of r278610 with a different fix.
llvm-svn: 278615
The auto-upgrade path could be called before the VST (global
names) was fully parsed, and thus intrinsic names were not
available and the autoupgrade logic could not operate.
Fix link failures with ThinLTO.
llvm-svn: 278610
Summary:
This patch adds IsVariadicFunction bit to summary in order
to not import variadic functions. Inliner doesn't inline
variadic functions because it is hard to reason about it.
This one small fix improves Importer by about 16%
(going from 86% to 100% of imported functions that are
inlined anywhere)
on some spec benchmarks like 'int' and others.
Reviewers: eraman, mehdi_amini, tejohnson
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D23339
llvm-svn: 278432
The linker supports a feature to force load an object from a static
archive if it defines an Objective-C category.
This API supports this feature by looking at every section in the
module to find if a category is defined in the module.
llvm-svn: 275125
Summary:
This complements the earlier addition of IntrWriteMem and IntrWriteArgMem
LLVM intrinsic properties, see D18291.
Also start using the attribute for memset, memcpy, and memmove intrinsics,
and remove their special-casing in BasicAliasAnalysis.
Reviewers: reames, joker.eph
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D18714
llvm-svn: 274485
Summary:
This represents the adjustment applied to the implicit 'this' parameter
in the prologue of a virtual method in the MS C++ ABI. The adjustment is
always zero unless multiple inheritance is involved.
This increases the size of DISubprogram by 8 bytes, unfortunately. The
adjustment really is a signed 32-bit integer. If this size increase is
too much, we could probably win it back by splitting out a subclass with
info specific to virtual methods (virtuality, vindex, thisadjustment,
containingType).
Reviewers: aprantl, dexonsmith
Subscribers: aaboud, amccarth, llvm-commits
Differential Revision: http://reviews.llvm.org/D21614
llvm-svn: 274325
This change is motivated by an upcoming change to the metadata representation
used for CFI. The indirect function call checker needs type information for
external function declarations in order to correctly generate jump table
entries for such declarations. We currently associate such type information
with declarations using a global metadata node, but I plan [1] to move all
such metadata to global object attachments.
In bitcode, metadata attachments for function declarations appear in the
global metadata block. This seems reasonable to me because I expect metadata
attachments on declarations to be uncommon. In the long term I'd also expect
this to be the case for CFI, because we'd want to use some specialized bitcode
format for this metadata that could be read as part of the ThinLTO thin-link
phase, which would mean that it would not appear in the global metadata block.
To solve the lazy loaded metadata issue I was seeing with D20147, I use the
same bitcode representation for metadata attachments for global variables as I
do for function declarations. Since there's a use case for metadata attachments
in the global metadata block, we might as well use that representation for
global variables as well, at least until we have a mechanism for lazy loading
global variables.
In the assembly format, the metadata attachments appear after the "declare"
keyword in order to avoid a parsing ambiguity.
[1] http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html
Differential Revision: http://reviews.llvm.org/D21052
llvm-svn: 273336
If a local_unnamed_addr attribute is attached to a global, the address
is known to be insignificant within the module. It is distinct from the
existing unnamed_addr attribute in that it only describes a local property
of the module rather than a global property of the symbol.
This attribute is intended to be used by the code generator and LTO to allow
the linker to decide whether the global needs to be in the symbol table. It is
possible to exclude a global from the symbol table if three things are true:
- This attribute is present on every instance of the global (which means that
the normal rule that the global must have a unique address can be broken without
being observable by the program by performing comparisons against the global's
address)
- The global has linkonce_odr linkage (which means that each linkage unit must have
its own copy of the global if it requires one, and the copy in each linkage unit
must be the same)
- It is a constant or a function (which means that the program cannot observe that
the unique-address rule has been broken by writing to the global)
Although this attribute could in principle be computed from the module
contents, LTO clients (i.e. linkers) will normally need to be able to compute
this property as part of symbol resolution, and it would be inefficient to
materialize every module just to compute it.
See:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html
for earlier discussion.
Part of the fix for PR27553.
Differential Revision: http://reviews.llvm.org/D20348
llvm-svn: 272709
r267296 used std::piecewise_construct without using
std::forward_as_tuple, and r267298 hacked it out (using an emplace_back
followed by a couple of reset() calls) because of a problem on a bot.
I'm finally circling back to call forward_as_tuple as I should have to
begin with (thanks to David Blaikie for pointing out the missing piece).
Note that this code uses emplace_back() instead of
push_back(make_pair()) because the move constructor for TrackingMDRef is
expensive (cheaper than a copy, but still expensive).
llvm-svn: 272306
Summary:
Now DISubroutineType has a 'cc' field which should be a DW_CC_ enum. If
it is present and non-zero, the backend will emit it as a
DW_AT_calling_convention attribute. On the CodeView side, we translate
it to the appropriate enum for the LF_PROCEDURE record.
I added a new LLVM vendor specific enum to the list of DWARF calling
conventions. DWARF does not appear to attempt to standardize these, so I
assume it's OK to do this until we coordinate with GCC on how to emit
vectorcall convention functions.
Reviewers: dexonsmith, majnemer, aaboud, amccarth
Subscribers: mehdi_amini, llvm-commits
Differential Revision: http://reviews.llvm.org/D21114
llvm-svn: 272197
This will be necessary to allow the global merge pass to attach
multiple debug info metadata nodes to global variables once we reverse
the edge from DIGlobalVariable to GlobalVariable.
Differential Revision: http://reviews.llvm.org/D20414
llvm-svn: 271358
This patch adds an IR, assembly and bitcode representation for metadata
attachments for globals. Future patches will port existing features to use
these new attachments.
Differential Revision: http://reviews.llvm.org/D20074
llvm-svn: 271348
When we have "Image Info Version" module flag but don't have "Class Properties"
module flag, set "Class Properties" module flag to 0, so we can correctly emit
errors when one module has the flag set and another module does not.
rdar://26469641
llvm-svn: 270791
The bitcode upgrade I added for DISubprogram in r266446 was based on the
assumption that the CU node for the subprogram was already materialized by the
time the DISubprogram is visited. This assumption may not hold true as future
versions of LLVM may decide to write out bitcode in a different order. This
patch corrects this by introducing a versioning bit next to the distinct flag to
unambiguously differentiate the new from the old record layouts.
Note for people stabilizing LLVM out-of-tree: This patch introduces a bitcode
incompatibility with llvm trunk revisions from r266446 — this commit. (But
D19987 will ensure that it degrades gracefully).
http://reviews.llvm.org/D20004
rdar://problem/26074194
llvm-svn: 268816
Summary:
With the removal of support for lazy parsing of combined index summary
records (e.g. r267344), we no longer need to include the summary record
bitcode offset in the VST entries for definitions. Change the combined
index format to be similar to the per-module index format in using value
ids to cross-reference from the summary record to the VST entry (rather
than the summary record bitcode offset to cross-reference in the other
direction).
The visible changes are:
1) Add the value id to the combined summary records
2) Remove the summary offset from the combined VST records, which has
the following effects:
- No longer need the VST_CODE_COMBINED_GVDEFENTRY record, as all
combined index VST entries now only contain the value id and
corresponding GUID.
- No longer have duplicate VST entries in the case where there are
multiple definitions of a symbol (e.g. weak/linkonce), as they all
have the same value id and GUID.
An implication of #2 above is that in order to hook up an alias to the
correct aliasee based on the value id of the aliasee recorded in the
combined index alias record, we need to scan the entries in the index
for that GUID to find the one from the same module (i.e. the case where
there are multiple entries for the aliasee). But the reader no longer
has to maintain a special map to hook up the alias/aliasee.
Reviewers: joker.eph
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19481
llvm-svn: 267712
There's hardly any functionality change here. Instead of calling
materializeMetadata on the first call to materialize(GlobalValue*), wait
until the first one that's actually going to do something. Noticed by
inspection; I don't have a concrete case where this makes a difference.
Added an assertion in materializeMetadata to be sure this (or a future
change) doesn't delay materializeMetadata after function-level metadata.
llvm-svn: 267345
Summary:
Remove the GlobalValueInfo and change the ModuleSummaryIndex to directly
reference summary objects. The info structure was there to support lazy
parsing of the combined index summary objects, which is no longer
needed and not supported.
Reviewers: joker.eph
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19462
llvm-svn: 267344
Add tests for some missing cases to bitcode upgrade in r267296.
- DICompositeType with an 'elements:' field, which will cause it to be
involved in a cycle after the upgrade.
- A DIDerivedType that references a class in 'extraData:'.
I updated test/Bitcode/dityperefs-3.8.ll with the missing cases and
regenerated test/Bitcode/dityperefs-3.8.ll.bc.
llvm-svn: 267332
Right now it only contains the LinkageType, but will be extended
with "hasSection", "isOptSize", "hasInlineAssembly", etc.
Differential Revision: http://reviews.llvm.org/D19404
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267319
Summary:
As discussed in D18298, some local globals can't
be renamed/promoted (because they have a section, or because
they are referenced from inline assembly).
To be able to detect naming collision, we need to keep around
the "GUID" using their original name without taking the linkage
into account.
Reviewers: tejohnson
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19454
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 267304
Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*. It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.
Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType. The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.
This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata. Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.
The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":
http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html
llvm-svn: 267296
Each reference to an unresolved MDNode is expensive, since the RAUW
support in MDNode uses a separate allocation and side map. Since
a distinct MDNode doesn't require its operands on creation (unlike
uniuqed nodes, there's no need to check for structural equivalence),
use nullptr for any of its unresolved operands. Besides reducing the
burden on MDNode maps, this can avoid allocating temporary MDNodes in
the first place.
We need some way to track operands. Invent DistinctMDOperandPlaceholder
for this purpose, which is a Metadata subclass that holds an ID and
points at its single user. DistinctMDOperandPlaceholder::replaceUseWith
is just like RAUW, but its name highlights that there is only ever
exactly one use.
There is no support for moving (or, obviously, copying) these. Move
support would be possible but expensive; leaving it unimplemented
prevents user error. In the BitcodeReader I originally considered
allocating on a BumpPtrAllocator and keeping a vector of pointers to
them, and then I realized that std::deque implements exactly this.
A couple of obvious follow-ups:
- Change ValueEnumerator to emit distinct nodes first to take more
advantage of this optimization. (How convenient... I think I might
have a couple of patches for this.)
- Change DIBuilder and its consumers (like CGDebugInfo in clang) to
use something like this when constructing debug info in the first
place.
llvm-svn: 267270
Consistently use the IsDistinct variable and start relying on it in
GET_OR_DISTINCT. This change has NFC, but prepares for using IsDistinct
to optimize the behaviour of the getMD() and getMDOrNull() helpers.
llvm-svn: 267268
