Commit Graph

193 Commits

Author SHA1 Message Date
Yaron Keren 55f5c3d43b Fix typo.
llvm-svn: 246538
2015-09-01 10:13:49 +00:00
Duncan P. N. Exon Smith f4967754a5 LTO: Cleanup parameter names and header docs, NFC
Follow LLVM style for the parameter names (`CamelCase` not `camelCase`),
and surface the header docs in doxygen.  No functionality change
intended.

llvm-svn: 246509
2015-08-31 23:44:06 +00:00
Peter Collingbourne c269ed5115 CodeGen: Introduce splitCodeGen and teach LTOCodeGenerator to use it.
llvm::splitCodeGen is a function that implements the core of parallel LTO
code generation. It uses llvm::SplitModule to split the module into linkable
partitions and spawning one code generation thread per partition. The function
produces multiple object files which can be linked in the usual way.

This has been threaded through to LTOCodeGenerator (and llvm-lto for testing
purposes). Separate patches will add parallel LTO support to the gold plugin
and lld.

Differential Revision: http://reviews.llvm.org/D12260

llvm-svn: 246236
2015-08-27 23:37:36 +00:00
Peter Collingbourne 9c8909dbd1 LTO: Simplify merged module ownership.
This change moves LTOCodeGenerator's ownership of the merged module to a
field of type std::unique_ptr<Module>. This helps simplify parts of the code
and clears the way for the module to be consumed by LLVM CodeGen (see D12132
review comments).

Differential Revision: http://reviews.llvm.org/D12205

llvm-svn: 245891
2015-08-24 22:22:53 +00:00
Peter Collingbourne e34034c8d0 LTO: Rename mergedModule variables to MergedModule to prepare for ownership change.
Also convert a few loops to range-for loops and correct a comment.

llvm-svn: 245874
2015-08-24 21:15:35 +00:00
Peter Collingbourne c7b675f48c LTO: Maintain target triple, FeatureStr and CGOptLevel in the module or LTOCodeGenerator.
This makes it easier to create new TargetMachines on demand.

llvm-svn: 245781
2015-08-22 02:25:53 +00:00
Peter Collingbourne 44ee84eec5 LTO: Change signature of LTOCodeGenerator::setCodePICModel() to take a Reloc::Model.
This allows us to remove a bunch of code in LTOCodeGenerator and llvm-lto
and has the side effect of improving error handling in the libLTO C API.

llvm-svn: 245756
2015-08-21 22:57:17 +00:00
Peter Collingbourne ec43d0f356 LTO: Simplify ownership of LTOCodeGenerator::TargetMach.
llvm-svn: 245671
2015-08-21 04:45:57 +00:00
Peter Collingbourne 2257512f87 LTO: Simplify ownership of LTOCodeGenerator::CodegenOptions.
llvm-svn: 245670
2015-08-21 04:45:55 +00:00
Chandler Carruth 7adc3a2b0e [PM/AA] Remove the last relics of the separate IPA library from LLVM,
folding the code into the main Analysis library.

There already wasn't much of a distinction between Analysis and IPA.
A number of the passes in Analysis are actually IPA passes, and there
doesn't seem to be any advantage to separating them.

Moreover, it makes it hard to have interactions between analyses that
are both local and interprocedural. In trying to make the Alias Analysis
infrastructure work with the new pass manager, it becomes particularly
awkward to navigate this split.

I've tried to find all the places where we referenced this, but I may
have missed some. I have also adjusted the C API to continue to be
equivalently functional after this change.

Differential Revision: http://reviews.llvm.org/D12075

llvm-svn: 245318
2015-08-18 17:51:53 +00:00
Mehdi Amini 26d481311a Remove access to the DataLayout in the TargetMachine
Summary:
Replace getDataLayout() with a createDataLayout() method to make
explicit that it is intended to create a DataLayout only and not
accessing it for other purpose.

This change is the last of a series of commits dedicated to have a
single DataLayout during compilation by using always the one owned
by the module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11103

(cherry picked from commit 5609fc56bca971e5a7efeaa6ca4676638eaec5ea)

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 243114
2015-07-24 16:04:22 +00:00
Mehdi Amini 5d8e569926 Revert "Remove access to the DataLayout in the TargetMachine"
This reverts commit 0f720d984f419c747709462f7476dff962c0bc41.

It breaks clang too badly, I need to prepare a proper patch for clang
first.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 243089
2015-07-24 03:36:55 +00:00
Mehdi Amini b4bc424c9a Remove access to the DataLayout in the TargetMachine
Summary:
Replace getDataLayout() with a createDataLayout() method to make
explicit that it is intended to create a DataLayout only and not
accessing it for other purpose.

This change is the last of a series of commits dedicated to have a
single DataLayout during compilation by using always the one owned
by the module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11103

(cherry picked from commit 5609fc56bca971e5a7efeaa6ca4676638eaec5ea)

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 243083
2015-07-24 01:44:39 +00:00
Peter Collingbourne 17eff10f68 LTO: expose LTO_SYMBOL_ALIAS, which indicates that the symbol is an alias.
This is needed for COFF linkers to distinguish between weak external aliases
and regular symbols with LLVM weak linkage, which are represented as strong
symbols in COFF.

llvm-svn: 241389
2015-07-04 03:42:35 +00:00
Peter Collingbourne aef3659e18 Teach LTOModule to emit linker flags for dllexported symbols, plus interface cleanup.
This change unifies how LTOModule and the backend obtain linker flags
for globals: via a new TargetLoweringObjectFile member function named
emitLinkerFlagsForGlobal. A new function LTOModule::getLinkerOpts() returns
the list of linker flags as a single concatenated string.

This change affects the C libLTO API: the function lto_module_get_*deplibs now
exposes an empty list, and lto_module_get_*linkeropts exposes a single element
which combines the contents of all observed flags. libLTO should never have
tried to parse the linker flags; it is the linker's job to do so. Because
linkers will need to be able to parse flags in regular object files, it
makes little sense for libLTO to have a redundant mechanism for doing so.

The new API is compatible with the old one. It is valid for a user to specify
multiple linker flags in a single pragma directive like this:

 #pragma comment(linker, "/defaultlib:foo /defaultlib:bar")

The previous implementation would not have exposed
either flag via lto_module_get_*deplibs (as the test in
TargetLoweringObjectFileCOFF::getDepLibFromLinkerOpt was case sensitive)
and would have exposed "/defaultlib:foo /defaultlib:bar" as a single flag via
lto_module_get_*linkeropts. This may have been a bug in the implementation,
but it does give us a chance to fix the interface.

Differential Revision: http://reviews.llvm.org/D10548

llvm-svn: 241010
2015-06-29 22:04:09 +00:00
Rafael Espindola c233f74e6e Simplify the Mangler interface now that DataLayout is mandatory.
We only need to pass in a DataLayout when mangling a raw string, not when
constructing the mangler.

llvm-svn: 240405
2015-06-23 13:59:29 +00:00
Rafael Espindola dcd1dca275 Return a unique_ptr from getLazyBitcodeModule and parseBitcodeFile. NFC.
llvm-svn: 239858
2015-06-16 22:27:55 +00:00
Douglas Katzman 8f01f1cfc3 Wrap some long lines in LLVMBuild files. NFC
As suggested by jroelofs in a prior review (D9752),
it makes sense to generally prefer multi-line format.

llvm-svn: 239632
2015-06-12 18:44:57 +00:00
Peter Collingbourne 485ad4860e LTO: expose LTO_SYMBOL_COMDAT flag, which indicates that the definition is part of a comdat group.
Reviewers: rafael

Subscribers: llvm-commits, ruiu

Differential Revision: http://reviews.llvm.org/D10330

llvm-svn: 239559
2015-06-11 21:41:27 +00:00
Peter Collingbourne 3cc69d90f0 Make the C++ LTO API easier to use from C++ clients.
Start using C++ types such as StringRef and MemoryBuffer in the C++ LTO
API. In doing so, clarify the ownership of the native object file: the caller
now owns it, not the LTOCodeGenerator. The C libLTO library has been modified
to use a derived class of LTOCodeGenerator that owns the object file.

Differential Revision: http://reviews.llvm.org/D10114

llvm-svn: 238776
2015-06-01 20:08:30 +00:00
Duncan P. N. Exon Smith 5a490d0026 LTO: Add API to choose whether to embed uselists
Reverse libLTO's default behaviour for preserving use-list order in
bitcode, and add API for controlling it.  The default setting is now
`false` (don't preserve them), which is consistent with `clang`'s
default behaviour.

Users of libLTO should call `lto_codegen_should_embed_uselists(CG,true)`
prior to calling `lto_codegen_write_merged_modules()` whenever the
output file isn't part of the production workflow in order to reproduce
results with subsequent calls to `llc`.

(I haven't added tests since `llvm-lto` (the test tool for LTO) doesn't
support bitcode output, and even if it did: there isn't actually a good
way to test whether a tool has passed the flag.  If the order is already
"natural" (if the order will already round-trip) then no use-list
directives are emitted at all.  At some point I'll circle back to add
tests to `llvm-as` (etc.) that they actually respect the flag, at which
point I can somehow add a test here as well.)

llvm-svn: 235943
2015-04-27 23:38:54 +00:00
Duncan P. N. Exon Smith 7832e0a2f0 LTO: Simplify code generator initialization
Simplify `LTOCodeGenerator` initialization by initializing simple fields
at their definition.

llvm-svn: 235939
2015-04-27 23:19:26 +00:00
Manman Ren ce0a066524 [LTO API] add lto_codegen_set_should_internalize.
When debugging LTO issues with ld64, we use -save-temps to save the merged
optimized bitcode file, then invoke ld64 again on the single bitcode file.
The saved bitcode file is already internalized, so we can call
lto_codegen_set_should_internalize and skip running internalization again.

rdar://20227235

llvm-svn: 235211
2015-04-17 17:10:09 +00:00
Duncan P. N. Exon Smith 8a7b84b4d0 uselistorder: Remove the global bits
Remove all the global bits to do with preserving use-list order by
moving the `cl::opt`s to the individual tools that want them.  There's a
minor functionality change to `libLTO`, in that you can't send in
`-preserve-bc-uselistorder=false`, but making that bit settable (if it's
worth doing) should be through explicit LTO API.

As a drive-by fix, I removed some includes of `UseListOrder.h` that were
made unnecessary by recent commits.

llvm-svn: 234973
2015-04-15 03:14:06 +00:00
Duncan P. N. Exon Smith a052ed6381 uselistorder: Pull the bit through WriteToBitcodFile()
Change the callers of `WriteToBitcodeFile()` to pass `true` or
`shouldPreserveBitcodeUseListOrder()` explicitly.  I left the callers
that want to send `false` alone.

I'll keep pushing the bit higher until hopefully I can delete the global
`cl::opt` entirely.

llvm-svn: 234957
2015-04-15 00:10:50 +00:00
Rafael Espindola 5560a4cfbd Use raw_pwrite_stream in the object writer/streamer.
The ELF object writer will take advantage of that in the next commit.

llvm-svn: 234950
2015-04-14 22:14:34 +00:00
Duncan P. N. Exon Smith c55dee1c2f IR: Set -preserve-bc-uselistorder=false by default
But keep it on by default in `llvm-as`, `opt`, `bugpoint`, `llvm-link`,
`llvm-extract`, and `LTOCodeGenerator`.  Part of PR5680.

llvm-svn: 234921
2015-04-14 18:33:00 +00:00
Rafael Espindola 5682ce2ceb Simplify use of formatted_raw_ostream.
formatted_raw_ostream is a wrapper over another stream to add column and line
number tracking.

It is used only for asm printing.

This patch moves the its creation down to where we know we are printing
assembly. This has the following advantages:

* Simpler lifetime management: std::unique_ptr
* We don't compute column and line number of object files :-)

llvm-svn: 234535
2015-04-09 21:06:08 +00:00
Rafael Espindola ee0dd4d289 This reverts commit r234460 and r234461.
Revert "Add classof implementations to the raw_ostream classes."
Revert "Use the cast machinery to remove dummy uses of formatted_raw_ostream."

The underlying issue can be fixed without classof.

llvm-svn: 234495
2015-04-09 15:54:59 +00:00
Rafael Espindola 132381f981 Use the cast machinery to remove dummy uses of formatted_raw_ostream.
If we know we are producing an object, we don't need to wrap the stream
in a formatted_raw_ostream anymore.

llvm-svn: 234461
2015-04-09 02:28:12 +00:00
Manman Ren ed6b5fc4b0 [LTO] do not run internalize pass from compileOptimized.
The input to compileOptimized is already optimized and internalized, so remove
internalize pass from compileOptimized.

rdar://20227235

llvm-svn: 234446
2015-04-08 22:02:11 +00:00
Yaron Keren 075759aadd Remove more superfluous .str() and replace std::string concatenation with Twine.
Following r233392, http://llvm.org/viewvc/llvm-project?rev=233392&view=rev.

llvm-svn: 233555
2015-03-30 15:42:36 +00:00
Duncan P. N. Exon Smith ab58a568ee Verifier: Remove the separate -verify-di pass
Remove `DebugInfoVerifierLegacyPass` and the `-verify-di` pass.
Instead, call into the `DebugInfoVerifier` from inside
`VerifierLegacyPass::finalizeModule()`.  This better matches the logic
in `verifyModule()` (used by the new PassManager), avoids requiring two
separate passes to verify the IR, and makes the API for "add a pass to
verify the IR" simple.

Note: the `-verify-debug-info` flag still works (for now, at least;
eventually it might make sense to just remove it).

llvm-svn: 232772
2015-03-19 22:24:17 +00:00
Peter Collingbourne 070843d60b libLTO, llvm-lto, gold: Introduce flag for controlling optimization level.
This change also introduces a link-time optimization level of 1. This
optimization level runs only the globaldce pass as well as cleanup passes for
passes that run at -O0, specifically simplifycfg which cleans up lowerbitsets.

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266951.html

llvm-svn: 232769
2015-03-19 22:01:00 +00:00
Manman Ren 4a9b0ebe83 Add a parameter for getLazyBitcodeModule to lazily load Metadata.
We only defer loading metadata inside ParseModule when ShouldLazyLoadMetadata
is true and we have not loaded any Metadata block yet.

This commit implements all-or-nothing loading of Metadata. If there is a
request to load any metadata block, we will load all deferred metadata blocks.

We make sure the deferred metadata blocks are loaded before we materialize any
function or a module.

The default value of the added parameter ShouldLazyLoadMetadata for
getLazyBitcodeModule is false, so the default behavior stays the same.

We only set the parameter to true when creating LTOModule in local contexts.
These can only really be used for parsing symbols, so it's unnecessary to ever
load the metadata blocks.

If we are going to enable lazy-loading of Metadata for other usages of
getLazyBitcodeModule, where deferred metadata blocks need to be loaded, we can
expose BitcodeReader::materializeMetadata to Module, similar to
Module::materialize.

rdar://19804575

llvm-svn: 232198
2015-03-13 19:24:30 +00:00
Mehdi Amini 46a43556db Make DataLayout Non-Optional in the Module
Summary:
DataLayout keeps the string used for its creation.

As a side effect it is no longer needed in the Module.
This is "almost" NFC, the string is no longer
canonicalized, you can't rely on two "equals" DataLayout
having the same string returned by getStringRepresentation().

Get rid of DataLayoutPass: the DataLayout is in the Module

The DataLayout is "per-module", let's enforce this by not
duplicating it more than necessary.
One more step toward non-optionality of the DataLayout in the
module.

Make DataLayout Non-Optional in the Module

Module->getDataLayout() will never returns nullptr anymore.

Reviewers: echristo

Subscribers: resistor, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D7992

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231270
2015-03-04 18:43:29 +00:00
Manman Ren 082a336a89 [LTO API] fix memory leakage introduced at r230290.
r230290 released the LLVM module but not the LTOModule.

rdar://19024554

llvm-svn: 230544
2015-02-25 21:20:53 +00:00
Manman Ren 6487ce955a [LTO API] add lto_codegen_set_module to set the destination module.
When debugging LTO issues with ld64, we use -save-temps to save the merged
optimized bitcode file, then invoke ld64 again on the single bitcode file to
speed up debugging code generation passes and ld64 stuff after code generation.

llvm linking a single bitcode file via lto_codegen_add_module will generate a
different bitcode file from the single input. With the newly-added
lto_codegen_set_module, we can make sure the destination module is the same as
the input.

lto_codegen_set_module will transfer the ownship of the module to code
generator.

rdar://19024554

llvm-svn: 230290
2015-02-24 00:45:56 +00:00
Chandler Carruth 30d69c2e36 [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00
Zachary Turner 3bd47cee78 Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects.
This allows IDEs to recognize the entire set of header files for
each of the core LLVM projects.

Differential Revision: http://reviews.llvm.org/D7526
Reviewed By: Chris Bieneman

llvm-svn: 228798
2015-02-11 03:28:02 +00:00
Manman Ren 8121e1db91 [LTO API] split lto_codegen_compile to lto_codegen_optimize and
lto_codegen_compile_optimized. Also add lto_api_version.

Before this commit, we can only dump the optimized bitcode after running
lto_codegen_compile, but it includes some impacts of running codegen passes,
one example is StackProtector pass. We will get assertion failure when running
llc on the optimized bitcode, because StackProtector is effectively run twice.

After splitting lto_codegen_compile, the linker can choose to dump the bitcode
before running lto_codegen_compile_optimized.

lto_api_version is added so ld64 can check for runtime-availability of the new
API.

rdar://19565500

llvm-svn: 228000
2015-02-03 18:39:15 +00:00
Eric Christopher 36fe028a2a Only access TLOF via the TargetMachine, not TargetLowering.
llvm-svn: 227949
2015-02-03 07:22:52 +00:00
Chandler Carruth 5ec2b1d11a [multiversion] Implement the old pass manager's TTI wrapper pass in
terms of the new pass manager's TargetIRAnalysis.

Yep, this is one of the nicer bits of the new pass manager's design.
Passes can in many cases operate in a vacuum and so we can just nest
things when convenient. This is particularly convenient here as I can
now consolidate all of the TargetMachine logic on this analysis.

The most important change here is that this pushes the function we need
TTI for all the way into the TargetMachine, and re-creates the TTI
object for each function rather than re-using it for each function.
We're now prepared to teach the targets to produce function-specific TTI
objects with specific subtargets cached, etc.

One piece of feedback I'd love here is whether its worth renaming any of
this stuff. None of the names really seem that awesome to me at this
point, but TargetTransformInfoWrapperPass is particularly ... odd.
TargetIRAnalysisWrapper might make more sense. I would want to do that
rename separately anyways, but let me know what you think.

llvm-svn: 227731
2015-02-01 12:26:09 +00:00
NAKAMURA Takumi 7ae226dfaf [CMake] LLVMLTO requires Intrinsics.gen since r227685 introduced llvm/Analysis/TargetTransformInfo.h.
llvm-svn: 227700
2015-02-01 00:55:43 +00:00
Chandler Carruth 93dcdc47db [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

llvm-svn: 227685
2015-01-31 11:17:59 +00:00
Chandler Carruth 1efa12d6d8 [PM] Sink the population of the pass manager with target-specific
analyses back into the LTO code generator.

The pass manager builder (and the transforms library in general)
shouldn't be referencing the target machine at all.

This makes the LTO population work like the others -- the data layout
and target transform info need to be pre-populated.

llvm-svn: 227576
2015-01-30 13:33:42 +00:00
Akira Hatanaka 8fba18e958 [LTO] Scan all per-function subtargets when collecting runtime library names.
accumulateAndSortLibcalls in LTOCodeGenerator.cpp collects names of runtime
library functions which are used to identify user-defined functions that should
be protected. Previously, this function would only scan the TargetLowering
object belonging to the "main" subtarget for the library function names. This
commit changes it to scan all per-function subtargets.

Differential Revision: http://reviews.llvm.org/D7275

llvm-svn: 227533
2015-01-30 01:16:24 +00:00
Eric Christopher 8b7706517c Move DataLayout back to the TargetMachine from TargetSubtargetInfo
derived classes.

Since global data alignment, layout, and mangling is often based on the
DataLayout, move it to the TargetMachine. This ensures that global
data is going to be layed out and mangled consistently if the subtarget
changes on a per function basis. Prior to this all targets(*) have
had subtarget dependent code moved out and onto the TargetMachine.

*One target hasn't been migrated as part of this change: R600. The
R600 port has, as a subtarget feature, the size of pointers and
this affects global data layout. I've currently hacked in a FIXME
to enable progress, but the port needs to be updated to either pass
the 64-bitness to the TargetMachine, or fix the DataLayout to
avoid subtarget dependent features.

llvm-svn: 227113
2015-01-26 19:03:15 +00:00
Chandler Carruth c0291865ed [PM] Rework how the TargetLibraryInfo pass integrates with the new pass
manager to support the actual uses of it. =]

When I ported instcombine to the new pass manager I discover that it
didn't work because TLI wasn't available in the right places. This is
a somewhat surprising and/or subtle aspect of the new pass manager
design that came up before but I think is useful to be reminded of:

While the new pass manager *allows* a function pass to query a module
analysis, it requires that the module analysis is already run and cached
prior to the function pass manager starting up, possibly with
a 'require<foo>' style utility in the pass pipeline. This is an
intentional hurdle because using a module analysis from a function pass
*requires* that the module analysis is run prior to entering the
function pass manager. Otherwise the other functions in the module could
be in who-knows-what state, etc.

A somewhat surprising consequence of this design decision (at least to
me) is that you have to design a function pass that leverages
a module analysis to do so as an optional feature. Even if that means
your function pass does no work in the absence of the module analysis,
you have to handle that possibility and remain conservatively correct.
This is a natural consequence of things being able to invalidate the
module analysis and us being unable to re-run it. And it's a generally
good thing because it lets us reorder passes arbitrarily without
breaking correctness, etc.

This ends up causing problems in one case. What if we have a module
analysis that is *definitionally* impossible to invalidate. In the
places this might come up, the analysis is usually also definitionally
trivial to run even while other transformation passes run on the module,
regardless of the state of anything. And so, it follows that it is
natural to have a hard requirement on such analyses from a function
pass.

It turns out, that TargetLibraryInfo is just such an analysis, and
InstCombine has a hard requirement on it.

The approach I've taken here is to produce an analysis that models this
flexibility by making it both a module and a function analysis. This
exposes the fact that it is in fact safe to compute at any point. We can
even make it a valid CGSCC analysis at some point if that is useful.
However, we don't want to have a copy of the actual target library info
state for each function! This state is specific to the triple. The
somewhat direct and blunt approach here is to turn TLI into a pimpl,
with the state and mutators in the implementation class and the query
routines primarily in the wrapper. Then the analysis can lazily
construct and cache the implementations, keyed on the triple, and
on-demand produce wrappers of them for each function.

One minor annoyance is that we will end up with a wrapper for each
function in the module. While this is a bit wasteful (one pointer per
function) it seems tolerable. And it has the advantage of ensuring that
we pay the absolute minimum synchronization cost to access this
information should we end up with a nice parallel function pass manager
in the future. We could look into trying to mark when analysis results
are especially cheap to recompute and more eagerly GC-ing the cached
results, or we could look at supporting a variant of analyses whose
results are specifically *not* cached and expected to just be used and
discarded by the consumer. Either way, these seem like incremental
enhancements that should happen when we start profiling the memory and
CPU usage of the new pass manager and not before.

The other minor annoyance is that if we end up using the TLI in both
a module pass and a function pass, those will be produced by two
separate analyses, and thus will point to separate copies of the
implementation state. While a minor issue, I dislike this and would like
to find a way to cleanly allow a single analysis instance to be used
across multiple IR unit managers. But I don't have a good solution to
this today, and I don't want to hold up all of the work waiting to come
up with one. This too seems like a reasonable thing to incrementally
improve later.

llvm-svn: 226981
2015-01-24 02:06:09 +00:00
Chandler Carruth 1edb9d63e9 [PM] Separate the InstCombiner from its pass.
This creates a small internal pass which runs the InstCombiner over
a function. This is the hard part of porting InstCombine to the new pass
manager, as at this point none of the code in InstCombine has access to
a Pass object any longer.

The resulting interface for the InstCombiner is pretty terrible. I'm not
planning on leaving it that way. The key thing missing is that we need
to separate the worklist from the combiner a touch more. Once that's
done, it should be possible for *any* part of LLVM to just create
a worklist with instructions, populate it, and then combine it until
empty. The pass will just be the (obvious and important) special case of
doing that for an entire function body.

For now, this is the first increment of factoring to make all of this
work.

llvm-svn: 226618
2015-01-20 22:44:35 +00:00