Commit Graph

501 Commits

Author SHA1 Message Date
Johannes Doerfert 3dca83961c Reapply "[Attributor] Disable simplification AAs if a callback is present""
This reapplies commit cbb709e251 and
includes the use of the lookup method instead of operator[] to avoid
accidentally setting (empty) simplification callbacks.

This reverts commit aa27430a62.
2021-07-27 19:14:50 -05:00
Johannes Doerfert c55e18824d [Attributor][FIX] Copy all members in the assignment operator
Also improve debug output slightly.
2021-07-27 01:44:13 -05:00
Johannes Doerfert 25a3130d89 [Local] Do not introduce a new `llvm.trap` before `unreachable`
This is the second attempt to remove the `llvm.trap` insertion after
https://reviews.llvm.org/rGe14e7bc4b889dfaffb7180d176a03311df2d4ae6
reverted the first one. It is not clear what the exact issue was back
then and it might already be gone by now, it has been >5 years after
all.

Replaces D106299.

Differential Revision: https://reviews.llvm.org/D106308
2021-07-26 23:33:36 -05:00
Johannes Doerfert adddd3dbda [Attributor] Introduce getPotentialCopiesOfStoredValue and use it
This patch introduces `getPotentialCopiesOfStoredValue` which uses
AAPointerInfo to determine all "aliases" or "potential copies" of a
value that is stored into memory. This operation can fail but if it
succeeds it means we can visit all "uses" of a value even if it is
temporarily stored in memory.

There are two users for the function:
  1) `Attributor::checkForAllUses` which will now ignore the value use
     in a store if all "potential copies" can be identified and instead
     be visited. This allows various AAs, including AAPointerInfo
     itself, to look through memory.
  2) `AANoCapture` which uses a custom use tracking through the
     CaptureTracker interface and therefore needs to be thought
     explicitly.

Differential Revision: https://reviews.llvm.org/D106185
2021-07-26 23:33:36 -05:00
Kuter Dinel 96709823ec [AMDGPU] Deduce attributes with the Attributor
This patch introduces a pass that uses the Attributor to deduce AMDGPU specific attributes.

Reviewed By: jdoerfert, arsenm

Differential Revision: https://reviews.llvm.org/D104997
2021-07-24 06:07:15 +03:00
Kuter Dinel 0cd964ff25 [Attributor][FIX] checkForAllInstructions, correctly handle declarations
checkForAllInstructions was not handling declarations correctly.
It should have been returning false when it gets called on a declaration

The patch also fixes a test case for AAFunctionReachability for it to be able
to pass after the changes to the checkForAllinstructions.

Differential Revision: https://reviews.llvm.org/D106625
2021-07-24 02:21:29 +03:00
Johannes Doerfert 6ca969353c [Attributor] If provided, only look at simplification callbacks not IR
A simplification callback can mean that the IR value is modified beyond
the apparent IR semantics. That is, a `i1 true` could be replaced by an
`i1 false` based on high-level domain-specific information. If a user
provides a simplification callback we will not look at the IR but
instead give up if the callback returns a nullptr.
2021-07-22 23:57:37 -05:00
Johannes Doerfert 0c0eb76782 [Attributor][FIX] Improve call graph updating
If we remove a non-intrinsic instruction we need to tell the (old) call
graph about it. This caused problems with some features down the line as
they allowed to removed calls more aggressively.
2021-07-22 00:07:56 -05:00
Johannes Doerfert 94d3b59c56 [Attributor][FIX] Do not introduce multiple instances of SSA values
If we have a recursive function we could create multiple instantiations
of an SSA value, one per recursive invocation of the function. This is a
problem as we use SSA value equality in various places. The basic idea
follows from this test:

```
static int r(int c, int *a) {
  int X;
  return c ? r(false, &X) : a == &X;
}

int test(int c) {
  return r(c, undef);
}
```

If we look through the argument `a` we will end up with `X`. Using SSA
value equality we will fold `a == &X` to true and return true even
though it should have been false because `a` and `&X` are from different
instantiations of the function.

Various tests for this  have been placed in value-simplify-instances.ll
and this commit fixes them all by avoiding to produce simplified values
that could be non-unique at runtime. Thus, the result of a simplify
value call will always be unique at runtime or the original value, both
do not allow to accidentally compare two instances of a value with each
other and conclude they are equal statically (pointer equivalence) while
they are unequal at runtime.
2021-07-22 00:07:55 -05:00
Johannes Doerfert c819266ecc [Attributor] Improve the Attributor::getAssumedConstant interface
Similar to Attributor::getAssumedSimplified we need to allow IRPs
directly to get the right simplification callback (and context).
2021-07-22 00:07:55 -05:00
Johannes Doerfert c7781a0978 [Attributor][NFC] Clang format 2021-07-21 22:51:05 -05:00
Giorgis Georgakoudis 3f71b425b2 [Attributor] Preserve BBs and instructions added in AA manifests
Manifesting AbstractAttributes may add new BBs in the IR. This patch provides an interface to register those BBs in the Attributor so that those BBs and containing instructions are not deleted as dead.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106383
2021-07-21 11:27:00 -07:00
Johannes Doerfert c2281f1565 [Attributor] Introduce AAPointerInfo
This patch introduces AAPointerInfo which tracks the uses of a pointer
and places them in "bins" based on their offset from the base and access
size.

As with other AAs, any pointer can be tracked but it is up to the user
to make sense of the results. The user in this patch is AAValueSimplify
and AAPotentialValues which both utilize AAPointerInfo to determine the
value of a load. For now, this is restricted to loads of allocas and
internal globals. Through the use of AAPointerInfo and the "bins" we can
track struct members separately. The users also know that storing only
zeros (at unknown indices) will result in loading only 0 (from unknown
indices). Other than that, the users are flow and context insensitive
(for now).

To deal with the "bins" more easily, AAPointerInfo provides a
forallInterfearingAccesses that applies a callback on all accesses
that might interfere with a given load or store.

Differential Revision: https://reviews.llvm.org/D104432
2021-07-19 22:48:35 -05:00
Johannes Doerfert 28c78a9e12 [Attributor] Simplify loads
As a first step to simplify loads we only handle `null` and `undef`
underlying objects, as well as objects that have the load as a single user.
Loads of those values can be replaced by the initializer, if any.
Proper reasoning is introduced in a follow up patch

Differential Revision: https://reviews.llvm.org/D103862
2021-07-19 22:47:29 -05:00
Shilei Tian c23da666b5 [Attributor] Add support for compound assignment for ChangeStatus
A common use of `ChangeStatus` is as follows:
```
ChangeStatus Changed = ChangeStatus::UNCHANGED;
Changed |= foo();
```
where `foo` returns `ChangeStatus` as well. Currently `ChangeStatus` doesn't
support compound assignment, we have to write as
```
Changed = Changed | foo();
```
which is not that convenient.

This patch add the support for compound assignment for `ChangeStatus`. Compound
assignment is usually implemented as a member function, and binary arithmetic
operator is therefore implemented using compound assignment. However, unlike
regular C++ class, enum class doesn't support member functions. As a result, they
can only be implemented in the way shown in the patch.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106109
2021-07-15 23:51:46 -04:00
Johannes Doerfert 792aac9897 [Attributor][NFCI] Add UsedAssumedInformation to more interfaces
As with other Attributor interfaces we often want to know if assumed
information was used to answer a query. This is important if only
known information is allowed or if known information can lead to an
early fixpoint. The users have been adjusted but none of them utilizes
the new information yet.
2021-07-11 19:18:03 -05:00
Johannes Doerfert d9659bf6a0 [OpenMP] Create custom state machines for generic target regions
In the spirit of TRegions [0], this patch creates a custom state
machine for a generic target region based on the potentially called
parallel regions.

The code analysis is done interprocedurally via an abstract attribute
(AAKernelInfo). All outermost parallel regions are collected and we
check if there might be unknown outermost parallel regions for which
we need an indirect call. Other AAKernelInfo extensions are expected.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

Differential Revision: https://reviews.llvm.org/D101977
2021-07-10 17:57:08 -05:00
Johannes Doerfert c1c1fe9385 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 16:32:24 -05:00
Johannes Doerfert dbb3a65f5b [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 16:09:30 -05:00
Johannes Doerfert 5ef18e2421 [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 15:52:36 -05:00
Johannes Doerfert 5b12cf3e65 [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 15:47:20 -05:00
Nico Weber d3e7491333 Revert Attributor patch series
Broke check-clang, see https://reviews.llvm.org/D102307#2869065
Ran `git revert -n ebbe149a6f08535ede848a531a601ae6591cfbc5..269416d41908bb670f67af689155d5ab8eea689a`
2021-07-10 16:15:55 -04:00
Johannes Doerfert 269416d419 [Attributor][NFCI] Add UsedAssumedInformation to more interfaces
As with other Attributor interfaces we often want to know if assumed
information was used to answer a query. This is important if only
known information is allowed or if known information can lead to an
early fixpoint. The users have been adjusted but none of them utilizes
the new information yet.
2021-07-10 12:32:51 -05:00
Johannes Doerfert ae08df87df [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 12:32:50 -05:00
Johannes Doerfert f0628c6ff7 [OpenMP] Create custom state machines for generic target regions
In the spirit of TRegions [0], this patch creates a custom state
machine for a generic target region based on the potentially called
parallel regions.

The code analysis is done interprocedurally via an abstract attribute
(AAKernelInfo). All outermost parallel regions are collected and we
check if there might be unknown outermost parallel regions for which
we need an indirect call. Other AAKernelInfo extensions are expected.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

Differential Revision: https://reviews.llvm.org/D101977
2021-07-10 12:32:50 -05:00
Johannes Doerfert 1eb31d6de3 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 12:32:50 -05:00
Johannes Doerfert 374e573cfc [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 12:32:50 -05:00
Johannes Doerfert be5d46e9bb [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 12:32:49 -05:00
Johannes Doerfert 168a9234d7 [Attributor][FIX] Replace uses first, then values
Before we replaced value by registering all their uses. However, as we
replace a value old uses become stale. We now replace values explicitly
and keep track of "new values" when doing so to avoid replacing only
uses in stale/old values but not their replacements.
2021-07-06 22:43:51 -05:00
Johannes Doerfert aa3768278d [Attributor] Introduce a helper function to deal with undef + none
We often need to deal with the value lattice that contains none and
undef as special values. A simple helper makes this much nicer.

Differential Revision: https://reviews.llvm.org/D103857
2021-07-06 22:41:21 -05:00
Johannes Doerfert fc82409b5c [Attributor] Simplify operands inside of simplification AAs first
When we do simplification via AAPotentialValues or AAValueConstantRange
we need to simplify the operands of an instruction we deconstruct first.
This does not only improve the result, see for example range.ll, but is
required as we allow outside AAs to provide simplification rules via
callbacks. If we do ignore the simplification rules and base other
simplifications on the IR instead we can create an inconsistent state.
2021-07-06 22:41:18 -05:00
Johannes Doerfert 7af91a2b8f [Attributor][NFCI] Make the state of AAValueSimplify explicit
As we have done with other states we want the AAValueSimplify state to
be explicit to use it more easily in our helpers.
2021-06-29 09:38:22 -05:00
Joseph Huber b54ccab509 [Attributor] Add an option to increase the max number of iterations
Right now the Attributor defaults to 32 fixed point iterations unless it is set
explicitly by a command line flag. This patch allows this to be configured when
the attributor instance is created. The maximum is then increased in OpenMPOpt
if the target is a kernel. This is because the globalization analysis can result
in larger iteration counts due to many dependent instances running at once.

Depends on D102444

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D104416
2021-06-22 14:38:25 -04:00
Joseph Huber 03d7e61c87 [OpenMP] Internalize functions in OpenMPOpt to improve IPO passes
Summary:
Currently the attributor needs to give up if a function has external linkage.
This means that the optimization introduced in D97818 will only apply to static
functions. This change uses the Attributor to internalize OpenMP device
routines by making a copy of each function with private linkage and replacing
the uses in the module with it. This allows for the optimization to be applied
to any regular function.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D102824
2021-06-22 12:38:10 -04:00
Haojian Wu 3f5d53a525 [Attributor] Fix UB behavior on uninitalized bool variables.
Found by ASAN.
2021-06-18 11:49:42 +02:00
Johannes Doerfert 30c9d68ad9 [Attributor][FIX] Arguments of unknown functions can be undef
This should fix PR50683. The wrong assumption was that we
could always know what the callee is when we replace a call site
argument with undef. We wanted to know that to remove the `noundef`
that might be attached to the argument. Since no callee means we
did the propagation on the caller site, there is no need to remove
an attribute. It is only needed if we replace all uses and therefore
pass `undef` instead of the value that was passed in otherwise.
2021-06-18 01:07:53 -05:00
Johannes Doerfert 666dc6f126 [Attributor] Use a centralized value simplification interface
To allow outside AAs that simplify values we need to ensure all value
simplification goes through the Attributor, not AAValueSimplify (or any
of the other AAs we have already like AAPotentialValues). This patch
also introduces an interface for the outside AAs to register
simplification callbacks for an IRPosition. To make this work as
expected we have to pass IRPositions instead of Values in
AAValueSimplify, which makes sense by itself.
2021-06-18 01:07:53 -05:00
Johannes Doerfert d9194b6efb [Attributor] Introduce a helper do deal with constant type mismatches
If we simplify values we sometimes end up with type mismatches. If the
value is a constant we can often cast it though to still allow
propagation. The logic is now put into a helper and it replaces some
ad hoc things we did before.

This also introduces the AA namespace for abstract attribute related
functions and types.

Differential Revision: https://reviews.llvm.org/D103856
2021-06-18 01:07:52 -05:00
Kuter Dinel eaf1b6810c [Attributor] Derive AACallEdges attribute
This attribute computes the optimistic live call edges using the attributor
liveness information. This attribute will be used for deriving a
inter-procedural function reachability attribute.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D104059
2021-06-18 03:29:22 +03:00
Johannes Doerfert 6caea8a7fa [Attributor] Introduce a helper do deal with constant type mismatches
If we simplify values we sometimes end up with type mismatches. If the
value is a constant we can often cast it though to still allow
propagation. The logic is now put into a helper and it replaces some
ad hoc things we did before.

This also introduces the AA namespace for abstract attribute related
functions and types.
2021-05-23 23:00:40 -05:00
Johannes Doerfert 1ba2929bb8 [Attributor] Be more careful to not disturb the CG outside the SCC
We have seen various problems when the call graph was not updated or
the updated did not succeed because it involved functions outside the
SCC. This patch adds assertions and checks to avoid accidentally
changing something outside the SCC that would impact the call graph.
It also prevents us from reanalyzing functions outside the current
SCC which could cause problems on its own. Note that the transformations
we do might cause the CG to be "more precise" but the original one would
always be a super set of the most precise one. Since the call graph is
by nature an approximation, it is good enough to have a super set of all
call edges.
2021-05-23 23:00:39 -05:00
Johannes Doerfert e93ac1e2de [Attributor][FIX] Account for undef in the constant value lattice
The constant value lattice looks like this

```
  <None>
     |
  <undef>
  /  |   \
... <0>  ...
 \   |   /
 <unknown>
```
We did not account for the undef and assumed a value meant we could not
change anymore. Now we actually check if we have the same value as
before, which will signal CHANGED to the users when we go from undef to
a specific constant.

This fixes, among other things, the bug exposed by @ipccp4 in
`value-simplify.ll`.
2021-05-23 20:47:06 -05:00
Johannes Doerfert 2bc51d39db [Attributor][NFC] Add helpful debug outputs 2021-05-23 20:47:05 -05:00
Kuter Dinel 64ef29bc66 [Attributor] Call site specific AAValueSimplification and AAIsDead.
This patch makes it possible to do call site specific deductions
for AAValueSimplification and AAIsDead.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84722
2021-05-15 21:39:07 +00:00
Benjamin Kramer 7e5682ee62 [ADT] Make TrackingStatistic's ctor constexpr
This lets clang diagnose unused statistics, so remove them.
2021-04-28 12:00:17 +02:00
Philip Reames 9ef6aa020b Plumb AssumeInst through operand bundle apis [nfc]
Follow up to a6d2a8d6f5.  This covers all the public interfaces of the bundle related code.  I tried to cleanup the internals where the changes were obvious, but there's definitely more room for improvement.
2021-04-06 12:53:53 -07:00
Abhina Sreeskantharajan 82b3e28e83 [SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text
Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.

Solution:
This patch adds two new flags

  - OF_CRLF which indicates that CRLF translation is used.
  - OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.

Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.

So this is the behaviour per platform with my patch:

z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode

Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return

The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
  if (Flags & OF_CRLF)
    CrtOpenFlags |= _O_TEXT;
```

These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99426
2021-04-06 07:23:31 -04:00
kuterd d75c9e61a5 [Attributor] Attributor call site specific AAValueConstantRange
This patch makes uses of the context bridges introduced in D83299 to make
AAValueConstantRange call site specific.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D83744
2021-03-11 01:19:44 +03:00
Johannes Doerfert 5b70c12f3e [Attributor] Make DepClass a required argument
We often used a sub-optimal dependence class in the past because we
didn't see the argument. Let's make it explicit so we remember to think
about it.
2021-03-04 00:35:52 -06:00
Johannes Doerfert e592dad82e [Attributor] Fold "TrackDependence" into the DepClassTy enum
We don't need a bool and an enum to express the three options we
currently have. This makes the interface nicer and much easier to
use optional dependencies. Also avoids mistakes where the bool is
false and enum ignored.
2021-03-04 00:35:52 -06:00
William S. Moses b077d82b00 [Attributor] Conditinoally delete fns
Allow the attributor to delete functions only if requested

Differential Revision: https://reviews.llvm.org/D97238
2021-02-27 20:37:42 -05:00
Duncan P. N. Exon Smith 22a52dfddc TransformUtils: Fix metadata handling in CloneModule (and improve CloneFunctionInto)
This commit fixes how metadata is handled in CloneModule to be sound,
and improves how it's handled in CloneFunctionInto (although the latter
is still awkward when called within a module).

Ruiling Song pointed out in PR48841 that CloneModule was changed to
unsoundly use the RF_ReuseAndMutateDistinctMDs flag (renamed in
fa35c1f80f for clarity). This flag papered
over a crash caused by other various changes made to CloneFunctionInto
over the past few years that made it unsound to use cloning between
different modules.

(This commit partially addresses PR48841, fixing the repro from
preprocessed source but not textual IR. MDNodeMapper::mapDistinctNode
became unsound in df763188c9 and this
commit does not address that regression.)

RF_ReuseAndMutateDistinctMDs is designed for the IRMover to use,
avoiding unnecessary clones of all referenced metadata when linking
between modules (with IRMover, the source module is discarded after
linking). It never makes sense to use when you're not discarding the
source. This commit drops its incorrect use in CloneModule.

Sadly, the right thing to do with metadata when cloning a function is
complicated, and this patch doesn't totally fix it.

The first problem is that there are two different types of referenceable
metadata and it's not obvious what to with one of them when remapping.

- `!0 = !{!1}` is metadata's version of a constant. Programatically it's
  called "uniqued" (probably a better term would be "constant") because,
  like `ConstantArray`, it's stored in uniquing tables. Once it's
  constructed, it's illegal to change its arguments.
- `!0 = distinct !{!1}` is a bit closer to a global variable. It's legal
  to change the operands after construction.

What should be done with distinct metadata when cloning functions within
the same module?

- Should new, cloned nodes be created?
- Should all references point to the same, old nodes?

The answer depends on whether that metadata is effectively owned by a
function.

And that's the second problem. Referenceable metadata's ownership model
is not clear or explicit. Technically, it's all stored on an
LLVMContext. However, any metadata that is `distinct`, that transitively
references a `distinct` node, or that transitively references a
GlobalValue is specific to a Module and is effectively owned by it. More
specifically, some metadata is effectively owned by a specific Function
within a module.

Effectively function-local metadata was introduced somewhere around
c10d0e5ccd, which made it illegal for two
functions to share a DISubprogram attachment.

When cloning a function within a module, you need to clone the
function-local debug info and suppress cloning of global debug info (the
status quo suppresses cloning some global debug info but not all). When
cloning a function to a new/different module, you need to clone all of
the debug info.

Here's what I think we should do (eventually? soon? not this patch
though):
- Distinguish explicitly (somehow) between pure constant metadata owned
  by the LLVMContext, global metadata owned by the Module, and local
  metadata owned by a GlobalValue (such as a function).
- Update CloneFunctionInto to trigger cloning of all "local" metadata
  (only), perhaps by adding a bit to RemapFlag. Alternatively, split
  out a separate function CloneFunctionMetadataInto to prime the
  metadata map that callers are updated to call ahead of time as
  appropriate.

Here's the somewhat more isolated fix in this patch:
- Converted the `ModuleLevelChanges` parameter to `CloneFunctionInto` to
  an enum called `CloneFunctionChangeType` that is one of
  LocalChangesOnly, GlobalChanges, DifferentModule, and ClonedModule.
- The code maintaining the "functions uniquely own subprograms"
  invariant is now only active in the first two cases, where a function
  is being cloned within a single module. That's necessary because this
  code inhibits cloning of (some) "global" metadata that's effectively
  owned by the module.
- The code maintaining the "all compile units must be explicitly
  referenced by !llvm.dbg.cu" invariant is now only active in the
  DifferentModule case, where a function is being cloned into a new
  module in isolation.
- CoroSplit.cpp's call to CloneFunctionInto in CoroCloner::create
  uses LocalChangeOnly, since fa635d730f
  only set `ModuleLevelChanges` to trigger cloning of local metadata.
- CloneModule drops its unsound use of RF_ReuseAndMutateDistinctMDs
  and special handling of !llvm.dbg.cu.
- Fixed some outdated header docs and left a couple of FIXMEs.

Differential Revision: https://reviews.llvm.org/D96531
2021-02-15 11:56:00 -08:00
Johannes Doerfert 81429abd83 [Attributor][FIX] Do not create UB by introducing a `noundef undef`
This was reported as PR49104. The reproducer uses varargs but the issue
is the same, we know an argument is dead but can't change the signature
for some reason. The PR49104 situation was: We are in an CG-SCC
traversal and we remove all the uses of an argument and proof it thereby
dead. However, if we do not remove the argument, via signature rewrite,
we need to ensure that the `undef` we introduce at the call site doesn't
clash with a `noundef` attribute.
2021-02-09 13:02:38 -06:00
Kazu Hirata 12fc9ca3a4 [llvm] Remove redundant string initialization (NFC)
Identified with readability-redundant-string-init.
2021-01-12 21:43:46 -08:00
dfukalov 2ce38b3f03 [NFC] Reduce include files dependency.
1. Removed #include "...AliasAnalysis.h" in other headers and modules.
2. Cleaned up includes in AliasAnalysis.h.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D92489
2020-12-03 18:25:05 +03:00
Johannes Doerfert d13daa4018 [Attributor] Finalize the CGUpdater after each SCC
This matches the new PM model.
2020-10-27 22:07:56 -05:00
Johannes Doerfert 50d34958df [Attributor][NFC] Introduce a debug counter for `AA::manifest`
This will simplify debugging and tracking down problems.
2020-10-27 22:07:56 -05:00
Johannes Doerfert 1d57b7f503 [Attributor][NFC] Print the right value in debug output 2020-10-27 22:07:55 -05:00
Johannes Doerfert 1c2531c9e1 [Attributor][FIX] Delete all unreachable static functions
Before we used to only mark unreachable static functions as dead if all
uses were known dead. Now we optimistically assume uses to be dead until
proven otherwise.
2020-10-27 22:07:55 -05:00
Johannes Doerfert 724fcce109 [Attributor][NFC] Clang-format 2020-10-27 22:07:55 -05:00
Johannes Doerfert cb813ab66a [Attributor][NFC] Improve time trace output 2020-10-27 22:07:54 -05:00
sstefan1 ce16be253c [Attributor][NFC] Make `createShallowWrapper()` available outside of Attributor
D85703 will need to create shallow wrappers in order to track the spmd icv. We need to make it available.

Differential Revision: https://reviews.llvm.org/D89342
2020-10-14 10:08:59 +02:00
Johannes Doerfert cefd2a2c70 [Attributor] Cleanup `IRPosition::getArgNo` usages
As we handle callback calls we need to disambiguate the call site
argument number from the callee argument number. While always equal in
non-callback calls, a callback comes with a partial parameter-argument
mapping so there is no implicit correspondence. Here we split
`IRPosition::getArgNo()` into two public functions, `getCallSiteArgNo()`
and `getCalleeArgNo()`. Usages are adjusted to pick the right one for
their purpose. This fixed some problems that would have been exposed as
we more aggressively optimize callbacks.
2020-09-09 00:52:17 -05:00
Johannes Doerfert c0ab901bdd [Attributor] Selectively look at the callee even when there are operand bundles
While operand bundles carry unpredictable semantics, we know some of
them and can therefore "ignore" them. In this case we allow to look at
the declaration of `llvm.assume` when asked for the attributes at a call
site. The assume operand bundles we have do not invalidate the
declaration attributes.

We cannot test this in isolation because the llvm.assume attributes are
determined by the parser. However, a follow up patch will provide test
coverage.
2020-09-09 00:52:17 -05:00
Johannes Doerfert d5d75f61e5 [Attributor] Provide a command line option that limits recursion depth
In `MultiSource/Benchmarks/tramp3d-v4/tramp3d-v4.cpp` we initialized
attributes until stack frame ~35k caused space to run out. The initial
size 1024 is pretty much random.
2020-09-09 00:47:02 -05:00
Johannes Doerfert 711bf7dcf9 [Attributor][FIX] Don't crash on internalizing linkonce_odr hidden functions
The CloneFunctionInto has implicit requirements with regards to the
linkage and visibility of the function. We now update these after we did
the CloneFunctionInto on the copy with the same linkage and visibility
as the original.
2020-09-07 23:38:09 -05:00
Johannes Doerfert e6208849c8 [Attributor][NFC] Change variable spelling 2020-09-07 23:38:09 -05:00
Johannes Doerfert ff70c25d76 [Attributor][NFC] Expand `auto` types (clang-fix-it) 2020-09-07 23:38:08 -05:00
Johannes Doerfert 79651265b2 [Attributor][FIX] Properly return changed if the IR was modified
Deleting or replacing anything is certainly a modification. This caused
a later assertion in IPSCCP when compiling 400.perlbench with the new PM.
I'm not sure how to test this.
2020-09-07 23:38:08 -05:00
sstefan1 5dfd7cc46c Reland [OpenMPOpt] ICV tracking for calls
The problem with module slice has been addressed in D86319

Introduce two new AAs. AAICVTrackerFunctionReturned which checks if a
function can have a unique ICV value after it is finished, and
AAICVCallSiteReturned which checks AAICVTrackerFunctionReturned for a
call site. This enables us to check the value of a call and if it
changes the ICV. This also changes the approach in
`getReplacementValues()` to a worklist-based approach so we can explore
all relevant BBs.

Differential Revision: https://reviews.llvm.org/D85544
2020-08-30 11:27:48 +02:00
sstefan1 8d8ce85b23 [Attributor] Introduce module slice.
Summary:
The module slice describes which functions we can analyze and transform
while working on an SCC as part of the Attributor-CGSCC pass. So far we
simply restricted it to the SCC.

Reviewers: jdoerfert

Differential Revision: https://reviews.llvm.org/D86319
2020-08-30 10:30:44 +02:00
Shinji Okumura 7a15dfd056 [Attributor] Fix AANoUndef identification
Even though `noundef` IR attribute might be attached to non-void type values, AANoUndef is mistakenly identified for pointer type values only.
This patch fixes that.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86737
2020-08-30 05:39:25 +09:00
Shinji Okumura c5e6872ec6 [Attributor] Guarantee getAAFor not to update AA in the manifestation stage
If we query an AA with `Attributor::getAAFor` in `AbstractAttribute::manifest`, the AA may be updated.
This patch makes use of the phase flag in Attributor, and handle `getAAFor` behavior according to the flag.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86635
2020-08-28 04:07:42 +09:00
Shinji Okumura 7a68f0f1e0 [Attributor] Add a phase flag to Attributor
Add a new flag that indicates which stage in the process we are in.
This flag is introduced for handling behavior of `getAAFor` according to the stage. (discussed in D86635)

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86678
2020-08-28 01:16:38 +09:00
serge-sans-paille 5621571fc7 Fix Attributor return status
Differential Revision: https://reviews.llvm.org/D86703
2020-08-27 15:01:04 +02:00
Shinji Okumura 6c25eca614 [Attributor] Add flag for undef value to the state of AAPotentialValues
Currently, an undef value is reduced to 0 when it is added to a set of potential values.
This patch introduces a flag for under values. By this, for example, we can merge two states `{undef}`, `{1}` to `{1}` (because we can reduce the undef to 1).

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D85592
2020-08-27 16:30:29 +09:00
kuterd 65fcc0ee31 [Attributor] Function seed allow list
-  Adds a command line option to seed only selected functions.
  - Makes seed allow listing exclusive to assertions enabled builds.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D86129
2020-08-21 23:55:26 +03:00
Johannes Doerfert 012819f301 [Attributor][FIX] Update the call graph properly when internalizing functions
The internal version is now part of the SCC, make sure to perform this
update.
2020-08-20 01:44:58 -05:00
Johannes Doerfert 1de70a724e Revert "[OpenMPOpt] ICV tracking for calls"
This commits breaks certain OpenMP codes (on power) because it expanded
the Attributor scope without telling the Attributor about the SCC
extend. See: https://reviews.llvm.org/D85544#2227611

This reverts commit b0b32e6490.
2020-08-20 00:00:35 -05:00
sstefan1 b0b32e6490 [OpenMPOpt] ICV tracking for calls
Introduce two new AAs. AAICVTrackerFunctionReturned which checks if a
function can have a unique ICV value after it is finished, and
AAICVCallSiteReturned which checks AAICVTrackerFunctionReturned for a
call site. This enables us to check the value of a call and if it
changes the ICV. This also changes the approach in
`getReplacementValues()` to a worklist-based approach so we can explore
all relevant BBs.

Differential Revision: https://reviews.llvm.org/D85544
2020-08-19 11:43:12 +02:00
Shinji Okumura 5e361e2aa4 [Attributor] Deduce noundef attribute
This patch introduces a new abstract attribute `AANoUndef` which corresponds to `noundef` IR attribute and deduce them.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D85184
2020-08-18 18:05:54 +09:00
Johannes Doerfert 1d99c3d707 [Attributor] We (should) keep the CG updated so we can mark it as preserved 2020-08-17 23:36:36 -05:00
Luofan Chen 266949b2bc [Attributor][NFC] Format code 2020-08-16 00:00:45 +08:00
Luofan Chen b7448a348b [Attributor][NFC] Use indexes instead of iterator
When adding elements when iterating, the iterator will become
valid, which could cause errors. This fixes the issue by using
indexes instead of iterator.
2020-08-15 23:09:46 +08:00
Luofan Chen 87a85f3d57 [Attributor] Use internalized version of non-exact functions
This patch internalize non-exact functions and replaces of their uses
with the internalized version. Doing this enables the analysis of
non-exact functions.

We can do this because some non-exact functions with the same name
whose linkage is `linkonce_odr` or `weak_odr` should have the same
semantics, so we can safely internalize and replace use of them (the
result of the other version of this function should be the same.).
Note that not all functions can be internalized, e.g., function with
`linkonce` or `weak` linkage.

For now when specified in commandline, we internalize all functions
that meet the requirements without calculating the cost of such
internalzation.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84167
2020-08-15 20:23:38 +08:00
Shinji Okumura c575ba28de [Attributor] AAPotentialValues Interface
This is a split patch of D80991.
This patch introduces AAPotentialValues and its interface only.
For more detail of AAPotentialValues abstract attribute, see the original patch.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D83283
2020-08-07 17:35:12 +09:00
Shinji Okumura 376b64926b Revert "[Attributor] AAPotentialValues Interface"
The commit cause build failure.
2020-08-02 22:49:52 +09:00
Shinji Okumura d3f01b6681 [Attributor] AAPotentialValues Interface
This is a split patch of D80991.
This patch introduces AAPotentialValues and its interface only.
For more detail of AAPotentialValues abstract attribute, see the original patch.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D83283
2020-08-02 19:12:17 +09:00
kuterd 49def10e02 [Attributor] Add time trace support.
This patch addes time trace functionality to have a better understanding
of the analysis times.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84980
2020-07-31 03:08:50 +03:00
Simon Pilgrim 6316b0023e Attributor.h - remove unnecessary includes. NFCI.
Fix implicit cpp include dependencies.
2020-07-30 15:26:41 +01:00
Luofan Chen 5ee07dc53f [Attributor] Track AA dependency using dependency graph
This patch added dependency graph to the attributor so that we can dump the dependencies between AAs more easily. We can also apply general graph algorithms to the graph, making it easier for us to create deep wrappers.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D78861
2020-07-28 18:02:49 +08:00
Luofan Chen 6db99d18b6 Revert "[Attributor] Track AA dependency using dependency graph"
This reverts commit 8df7af560a.
2020-07-15 11:48:08 +08:00
Luofan Chen 8df7af560a [Attributor] Track AA dependency using dependency graph
Summary: This patch added dependency graph to the attributor so that we can dump the dependencies between AAs more easily. We can also apply general graph algorithms to the graph, making it easier for us to create deep wrappers.

Reviewers: jdoerfert, sstefan1, uenoku, homerdin, baziotis

Reviewed By: jdoerfert

Subscribers: jfb, okura, mgrang, kuter, lebedev.ri, hiraditya, uenoku, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78861
2020-07-15 10:40:21 +08:00
Luofan Chen e21323a1e9 Revert "[Attributor] [WIP] Track AA dependency using dependency graph"
This reverts commit 6b78ed6070.
2020-07-15 10:33:55 +08:00
Luofan Chen 6b78ed6070 [Attributor] [WIP] Track AA dependency using dependency graph
Summary: This patch added dependency graph to the attributor so that we can dump the dependencies between AAs more easily. We can also apply general graph algorithms to the graph, making it easier for us to create deep wrappers.

Reviewers: jdoerfert, sstefan1, uenoku, homerdin, baziotis

Reviewed By: jdoerfert

Subscribers: jfb, okura, mgrang, kuter, lebedev.ri, hiraditya, uenoku, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78861
2020-07-15 10:21:49 +08:00
Luofan Chen 233af8958e [Attributor] Create getter function for the ID of the abstract attribute
Summary: The `getIdAddr()` function returns the address of the ID of the abstract attribute

Reviewers: jdoerfert, sstefan1, uenoku, homerdin, baziotis

Reviewed By: jdoerfert

Subscribers: okura, hiraditya, uenoku, kuter, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83172
2020-07-15 09:55:18 +08:00
kuter 4dbe82eef3 [Attributor] Introudce attribute seed allow list. 2020-07-12 02:25:33 +03:00
sstefan1 850b150cff [Attributor][NFC] Add more debug output for deleted functions 2020-07-11 14:26:08 +02:00
Simon Pilgrim 36bc10e74a [Transforms] Ensure we include CommandLine.h if we declare any cl::opt flags 2020-06-23 12:11:51 +01:00
clfbbn 10b0539772 [Attributor][NFC] Fix indentation
Summary: The patch D81022 seems to break the indentation of the `cleanupIR()` function. This patch fixes this problem

Reviewers: jdoerfert, sstefan1, uenoku

Reviewed By: jdoerfert

Subscribers: hiraditya, uenoku, kuter, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D82260
2020-06-21 15:43:32 +08:00