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542 Commits

Author SHA1 Message Date
Keno Fischer
a14938b8f9 [opt] Fix run-twice option for non-idempotent passes
Cloning the module was supposed to guard against the possibility
that the passes may be non-idempotent. However, for some reason
I decided to put that AFTER the passes had already run on the
module, defeating the point entirely. Fix that by moving up the
CloneModule as is done in llc.

llvm-svn: 254819
2015-12-05 01:38:12 +00:00
Keno Fischer
a15fc0e9a6 [opt] Fix sanitizer complaints about r254774
`Out` can be null if no output is requested, so move any access
to it inside the conditional. Thanks to Justin Bogner for finding
this.

llvm-svn: 254804
2015-12-05 00:06:37 +00:00
Keno Fischer
5b8c01f61a [llc/opt] Add an option to run all passes twice
Summary: Lately, I have submitted a number of patches to fix bugs that
only occurred when using the same pass manager to compile multiple
modules (generally these bugs are failure to reset some persistent
state). Unfortunately I don't think there is currently a way to test
that from the command line. This adds a very simple flag to both llc
and opt, under which the tools will simply re-run their respective
pass pipelines using the same pass manager on (a clone of the same
module). Additionally, we verify that both outputs are bitwise the
same.

Reviewers: yaron.keren

Subscribers: loladiro, yaron.keren, kcc, llvm-commits

Differential Revision: http://reviews.llvm.org/D14965

llvm-svn: 254774
2015-12-04 21:56:46 +00:00
Chandler Carruth
bf271cc4e6 [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
Reid Kleckner
620d7274c1 Expose sjlj preparation through opt for my own debugging purposes
llvm-svn: 241864
2015-07-09 21:48:40 +00:00
Matthias Braun
1151017f2a Revert "(HEAD -> master, origin/master, origin/HEAD) opt: Add option to strip or add llvm value names"
Accidental commit

This reverts commit r240583.

llvm-svn: 240584
2015-06-24 20:04:26 +00:00
Matthias Braun
7c02bf5cdb opt: Add option to strip or add llvm value names
llvm-svn: 240583
2015-06-24 20:03:33 +00:00
Douglas Katzman
5eb858225c 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
Akira Hatanaka
6f08fc2ca6 Remove NoFramePointerElim and NoFramePointerElimOverride from TargetOptions and
remove ExecutionEngine's dependence on CodeGen. NFC.

This is a follow-up to r238080.

Differential Revision: http://reviews.llvm.org/D9830

llvm-svn: 238244
2015-05-26 20:17:20 +00:00
Akira Hatanaka
626316f0c3 Stop resetting NoFramePointerElim in TargetMachine::resetTargetOptions.
This is part of the work to remove TargetMachine::resetTargetOptions.

In this patch, instead of updating global variable NoFramePointerElim in
resetTargetOptions, its use in DisableFramePointerElim is replaced with a call
to TargetFrameLowering::noFramePointerElim. This function determines on a
per-function basis if frame pointer elimination should be disabled.

There is no change in functionality except that cl:opt option "disable-fp-elim"
can now override function attribute "no-frame-pointer-elim". 

llvm-svn: 238080
2015-05-23 01:14:08 +00:00
Akira Hatanaka
c7f329a550 Simplify and rename function overrideFunctionAttributes. NFC.
This is in preparation to making changes needed to stop resetting
NoFramePointerElim in resetTargetOptions.

llvm-svn: 238079
2015-05-23 01:12:26 +00:00
Akira Hatanaka
ae9350177e Let llc and opt override "-target-cpu" and "-target-features" via command line
options.

This commit fixes a bug in llc and opt where "-mcpu" and "-mattr" wouldn't
override function attributes "-target-cpu" and "-target-features" in the IR.

Differential Revision: http://reviews.llvm.org/D9537

llvm-svn: 236677
2015-05-06 23:54:14 +00:00
Akira Hatanaka
59565430e4 Factor out a function which determines the cpu and feature strings based on
command line options -mcpu and -mattr. NFC.

llvm-svn: 236671
2015-05-06 23:49:24 +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
de4cfb653d DebugInfo: Delete DIDescriptor (but not its subclasses)
Delete `DIDescriptor` and update the remaining users.  I'll follow-up by
deleting subclasses in manageable groups (top-down).

llvm-svn: 235248
2015-04-18 00:35:36 +00:00
Duncan P. N. Exon Smith
1ea25bcecc DebugInfo: Gut DIType and subclasses
Continuing PR23080, gut `DIType` and its various subclasses, leaving
behind thin wrappers around the pointer types in the new debug info
hierarchy.

llvm-svn: 235064
2015-04-16 01:01:28 +00:00
Duncan P. N. Exon Smith
8654474680 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
8141c202b6 uselistorder: Pull the bit through PrintModulePass
Now the callers of `PrintModulePass()` (etc.) that care about use-list
order in assembly pass in the flag.

llvm-svn: 234969
2015-04-15 02:38:06 +00:00
Duncan P. N. Exon Smith
393c4f570f uselistorder: Pull bit through BitcodeWriterPass
Now the callers of `BitcodeWriterPass` decide whether or not to preserve
bitcode use-list order.

llvm-svn: 234959
2015-04-15 00:34:24 +00:00
Duncan P. N. Exon Smith
a8fd793406 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
Duncan P. N. Exon Smith
3b5fae31ff DebugInfo: Gut DISubprogram and DILexicalBlock*
Gut the `DIDescriptor` wrappers around `MDLocalScope` subclasses.  Note
that `DILexicalBlock` wraps `MDLexicalBlockBase`, not `MDLexicalBlock`.

llvm-svn: 234850
2015-04-14 03:40:37 +00:00
Duncan P. N. Exon Smith
447735d82c DebugInfo: Gut DINamespace and DITemplate*Parameter
Continue gutting `DIDescriptor` subclasses, turning them into
as-bare-as-possible pointer wrappers.

llvm-svn: 234843
2015-04-14 03:01:27 +00:00
Duncan P. N. Exon Smith
ba32e6fa81 IR: Stop using DIDescriptor::is*() and auto-casting
`DIDescriptor`'s subclasses allow construction from incompatible
pointers, and `DIDescriptor` defines a series of `isa<>`-like functions
(e.g., `isCompileUnit()` instead of `isa<MDCompileUnit>()`) that clients
tend to use like this:

    if (DICompileUnit(N).isCompileUnit())
      foo(DICompileUnit(N));

These construction patterns work together to make `DIDescriptor` behave
differently from normal pointers.

Instead, use built-in `isa<>`, `dyn_cast<>`, etc., and only build
`DIDescriptor`s from pointers that are valid for their type.

I've split this into a few commits for different parts of LLVM and clang
(to decrease the patch size and increase the chance of review).
Generally the changes I made were NFC, but in a few places I made things
stricter if it made sense from the surrounded code.

Eventually a follow-up commit will remove the API for the "old" way.

llvm-svn: 234255
2015-04-06 23:18:49 +00:00
Craig Topper
ab9b206e4a Add -mcpu=native support to opt.
llvm-svn: 233789
2015-04-01 05:32:04 +00:00
Duncan P. N. Exon Smith
cd3df9500c tools: Unify how verifyModule() is called
Unify the error messages for the various tools when `verifyModule()`
fails on an input module.  The "brave new way" is:

    lltool: path/to/input.ll: error: input module is broken!

llvm-svn: 233667
2015-03-31 03:07:23 +00:00
Duncan P. N. Exon Smith
7af4fb7b9f Verifier: Call verifyModule() from llc and opt
Change `llc` and `opt` to run `verifyModule()`.  This ensures that we
check the full module before `FunctionPass::doInitialization()` ever
gets called (I was getting crashes in `DwarfDebug` instead of verifier
failures when testing a WIP patch that checks operands of compile
units).  In `opt`, also move up debug-info-stripping so that it still
runs before verification.

There was a fair bit of broken code that was sitting in tree.
Interestingly, some were cases of a `select` that referred to itself in
`-instcombine` tests (apparently an intermediate result).  I split them
off to `*-noverify.ll` tests with RUN lines like this:

    opt < %s -S -disable-verify -instcombine | opt -S | FileCheck %s

This avoids verifying the input file (so we can get the broken code into
`-instcombine), but still verifies the output with a second call to
`opt` (to verify that `-instcombine` will clean it up like it should).

llvm-svn: 233432
2015-03-27 22:04:28 +00:00
Duncan P. N. Exon Smith
57ccff4630 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
Duncan P. N. Exon Smith
e8a4b7fb5f PassManagerBuilder: Remove effectively dead 'StripDebug' option
`StripDebug` was only used by tools/opt/opt.cpp in
`AddStandardLinkPasses()`, but opt.cpp adds the same pass based on its
command-line flag before it calls `AddStandardLinkPasses()`.  Stripping
debug info twice isn't very useful.

llvm-svn: 232765
2015-03-19 21:37:17 +00:00
Reid Kleckner
8387c0d5ea CMake: Disable ENABLE_EXPORTS for executables with MSVC
The MSVC linker won't produce a .lib file for an executable that doesn't
export anything, and LLVM doesn't maintain dllexport annotations or .def
files listing all C++ symbols. It also doesn't support exporting all
symbols, like binutils ld.

CMake 3.2 changed the Ninja generator to list both the .exe and .lib
files as outputs of executable build targets. Ninja would always re-link
executables with ENABLE_EXPORTS because the .lib output file was not
present, and therefore the target was out of date.

llvm-svn: 232662
2015-03-18 20:09:13 +00:00
Benjamin Kramer
5ce1e9672a Make helper functions static.
Found by -Wmissing-prototypes. NFC.

llvm-svn: 231664
2015-03-09 16:23:46 +00:00
Chandler Carruth
ef5afb1b16 [PM] Create a separate library for high-level pass management code.
This will provide the analogous replacements for the PassManagerBuilder
and other code long term. This code is extracted from the opt tool
currently, and I plan to extend it as I build up support for using the
new pass manager in Clang and other places.

Mailing this out for review in part to let folks comment on the terrible names
here. A brief word about why I chose the names I did.

The library is called "Passes" to try and make it clear that it is a high-level
utility and where *all* of the passes come together and are registered in
a common library. I didn't want it to be *limited* to a registry though, the
registry is just one component.

The class is a "PassBuilder" but this name I'm less happy with. It doesn't
build passes in any traditional sense and isn't a Builder-style API at all. The
class is a PassRegisterer or PassAdder, but neither of those really make a lot
of sense. This class is responsible for constructing passes for registry in an
analysis manager or for population of a pass pipeline. If anyone has a better
name, I would love to hear it. The other candidate I looked at was
PassRegistrar, but that doesn't really fit either. There is no register of all
the passes in use, and so I think continuing the "registry" analog outside of
the registry of pass *names* and *types* is a mistake. The objects themselves
are just objects with the new pass manager.

Differential Revision: http://reviews.llvm.org/D8054

llvm-svn: 231556
2015-03-07 09:02:36 +00:00
Mehdi Amini
29ebc2d39f 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
Reid Kleckner
53bc7b1858 Add an IR-to-IR test for dwarf EH preparation using opt
This tests the simple resume instruction elimination logic that we have
before making some changes to it.

llvm-svn: 229768
2015-02-18 23:17:41 +00:00
Chandler Carruth
18e8c62883 [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
Chandler Carruth
46a63acccc [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
Chandler Carruth
e1550cbb3c [PM] Port SimplifyCFG to the new pass manager.
This should be sufficient to replace the initial (minor) function pass
pipeline in Clang with the new pass manager. I'll probably add an (off
by default) flag to do that just to ensure we can get extra testing.

llvm-svn: 227726
2015-02-01 11:34:21 +00:00
Chandler Carruth
b4f6fbea29 [PM] Port EarlyCSE to the new pass manager.
I've added RUN lines both to the basic test for EarlyCSE and the
target-specific test, as this serves as a nice test that the TTI layer
in the new pass manager is in fact working well.

llvm-svn: 227725
2015-02-01 10:51:23 +00:00
Chandler Carruth
4efb41707c [PM] Port TTI to the new pass manager, introducing a TargetIRAnalysis to
produce it.

This adds a function to the TargetMachine that produces this analysis
via a callback for each function. This in turn faves the way to produce
a *different* TTI per-function with the correct subtarget cached.

I've also done the necessary wiring in the opt tool to thread the target
machine down and make it available to the pass registry so that we can
construct this analysis from a target machine when available.

llvm-svn: 227721
2015-02-01 10:11:22 +00:00
Chandler Carruth
72e4fd68d8 [PM] Refactor the analysis registration and pass pipeline parsing to
live in a class.

While this isn't really significant right now, I need to expose some
state to the pass construction expressions, and making them get
evaluated within a class context is a nice way to collect members that
they may need to access.

llvm-svn: 227715
2015-02-01 07:40:05 +00:00
Chandler Carruth
ad2d6dd7d3 [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
b2d6052871 [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00
Reid Kleckner
a789af4162 Add a Windows EH preparation pass that zaps resumes
If the personality is not a recognized MSVC personality function, this
pass delegates to the dwarf EH preparation pass. This chaining supports
people on *-windows-itanium or *-windows-gnu targets.

Currently this recognizes some personalities used by MSVC and turns
resume instructions into traps to avoid link errors.  Even if cleanups
are not used in the source program, LLVM requires the frontend to emit a
code path that resumes unwinding after an exception.  Clang does this,
and we get unreachable resume instructions. PR20300 covers cleaning up
these unreachable calls to resume.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D7216

llvm-svn: 227405
2015-01-29 00:41:44 +00:00
Chandler Carruth
0c0e20141c [PM] Port LowerExpectIntrinsic to the new pass manager.
This just lifts the logic into a static helper function, sinks the
legacy pass to be a trivial wrapper of that helper fuction, and adds
a trivial wrapper for the new PM as well. Not much to see here.

I switched a test case to run in both modes, but we have to strip the
dead prototypes separately as that pass isn't in the new pass manager
(yet).

llvm-svn: 226999
2015-01-24 11:13:02 +00:00
Chandler Carruth
3f06e001ed [PM] Port instcombine to the new pass manager!
This is exciting as this is a much more involved port. This is
a complex, existing transformation pass. All of the core logic is shared
between both old and new pass managers. Only the access to the analyses
is separate because the actual techniques are separate. This also uses
a bunch of different and interesting analyses and is the first time
where we need to use an analysis across an IR layer.

This also paves the way to expose instcombine utility functions. I've
got a static function that implements the core pass logic over
a function which might be mildly interesting, but more interesting is
likely exposing a routine which just uses instructions *already in* the
worklist and combines until empty.

I've switched one of my favorite instcombine tests to run with both as
well to make sure this keeps working.

llvm-svn: 226987
2015-01-24 04:19:17 +00:00
Chandler Carruth
359eeef50a [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
0147c610be [PM] Actually add the new pass manager support for the assumption cache.
I had already factored this analysis specifically to enable doing this,
but hadn't actually committed the necessary wiring to get at this from
the new pass manager. This also nicely shows how the separate cache
object can be directly managed by the new pass manager.

This analysis didn't have any direct tests and so I've added a printer
pass and a boring test case. I chose to print the i1 value which is
being assumed rather than the call to llvm.assume as that seems much
more useful for testing... but suggestions on an even better printing
strategy welcome. My main goal was to make sure things actually work. =]

llvm-svn: 226868
2015-01-22 21:53:09 +00:00
Chandler Carruth
7cd55815b7 [PM] Port LoopInfo to the new pass manager, adding both a LoopAnalysis
pass and a LoopPrinterPass with the expected associated wiring.

I've added a RUN line to the only test case (!!!) we have that actually
prints loops. Everything seems to be working.

This is somewhat exciting as this is the first analysis using another
analysis to go in for the new pass manager. =D I also believe it is the
last analysis necessary for porting instcombine, but of course I may yet
discover more.

llvm-svn: 226560
2015-01-20 10:58:50 +00:00
Chandler Carruth
0a49f1bfc1 [PM] Port TargetLibraryInfo to the new pass manager, provided by the
TargetLibraryAnalysis pass.

There are actually no direct tests of this already in the tree. I've
added the most basic test that the pass manager bits themselves work,
and the TLI object produced will be tested by an upcoming patches as
they port passes which rely on TLI.

This is starting to point out the awkwardness of the invalidate API --
it seems poorly fitting on the *result* object. I suspect I will change
it to live on the analysis instead, but that's not for this change, and
I'd rather have a few more passes ported in order to have more
experience with how this plays out.

I believe there is only one more analysis required in order to start
porting instcombine. =]

llvm-svn: 226160
2015-01-15 11:39:46 +00:00
Chandler Carruth
88fd126216 [PM] Separate the TargetLibraryInfo object from the immutable pass.
The pass is really just a means of accessing a cached instance of the
TargetLibraryInfo object, and this way we can re-use that object for the
new pass manager as its result.

Lots of delta, but nothing interesting happening here. This is the
common pattern that is developing to allow analyses to live in both the
old and new pass manager -- a wrapper pass in the old pass manager
emulates the separation intrinsic to the new pass manager between the
result and pass for analyses.

llvm-svn: 226157
2015-01-15 10:41:28 +00:00
Chandler Carruth
49a7633378 [PM] Move TargetLibraryInfo into the Analysis library.
While the term "Target" is in the name, it doesn't really have to do
with the LLVM Target library -- this isn't an abstraction which LLVM
targets generally need to implement or extend. It has much more to do
with modeling the various runtime libraries on different OSes and with
different runtime environments. The "target" in this sense is the more
general sense of a target of cross compilation.

This is in preparation for porting this analysis to the new pass
manager.

No functionality changed, and updates inbound for Clang and Polly.

llvm-svn: 226078
2015-01-15 02:16:27 +00:00