[clang][dataflow] Fix bug in `Value` comparison. (#76746)

Makes value equivalence require that the values have no properties,
except in
the case of equivalence by pointer equality (if the pointers a

[clang][dataflow] Fix bug in `Value` comparison. (#76746)

Makes value equivalence require that the values have no properties,
except in
the case of equivalence by pointer equality (if the pointers are equal,
nothing
else is checked).

Fixes issue #76459.

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[clang][dataflow] Eliminate `ReferenceValue`.

There are no remaining uses of this class in the framework.

This patch is part of the ongoing migration to strict handling of value categories (see htt

[clang][dataflow] Eliminate `ReferenceValue`.

There are no remaining uses of this class in the framework.

This patch is part of the ongoing migration to strict handling of value categories (see https://discourse.llvm.org/t/70086 for details).

Reviewed By: ymandel, xazax.hun, gribozavr2

Differential Revision: https://reviews.llvm.org/D155922

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[clang][dataflow] Use `IntegerValue` instead of `StructValue` in `ValueTest`.

Soon, it will no longer be possible to default-construct `StructValue`. For details, see https://discourse.llvm.org/t/70

[clang][dataflow] Use `IntegerValue` instead of `StructValue` in `ValueTest`.

Soon, it will no longer be possible to default-construct `StructValue`. For details, see https://discourse.llvm.org/t/70086.

For completeness, also add a test that `areEquivalentValues()` on different `IntegerValue`s returns false.

Reviewed By: xazax.hun, gribozavr2

Differential Revision: https://reviews.llvm.org/D154934

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Reland "[dataflow] Add dedicated representation of boolean formulas"

This reverts commit 7a72ce98224be76d9328e65eee472381f7c8e7fe.

Test problems were due to unspecified order of function arg evalua

Reland "[dataflow] Add dedicated representation of boolean formulas"

This reverts commit 7a72ce98224be76d9328e65eee472381f7c8e7fe.

Test problems were due to unspecified order of function arg evaluation.

Reland "[dataflow] Replace most BoolValue subclasses with references to Formula (and AtomicBoolValue => Atom and BoolValue => Formula where appropriate)"

This properly frees the Value hierarchy from managing boolean formulas.

We still distinguish AtomicBoolValue; this type is used in client code.
However we expect to convert such uses to BoolValue (where the
distinction is not needed) or Atom (where atomic identity is intended),
and then fold AtomicBoolValue into FormulaBoolValue.

We also distinguish TopBoolValue; this has distinct rules for
widen/join/equivalence, and top-ness is not represented in Formula.
It'd be nice to find a cleaner representation (e.g. the absence of a
formula), but no immediate plans.

For now, BoolValues with the same Formula are deduplicated. This doesn't
seem desirable, as Values are mutable by their creators (properties).
We can probably drop this for FormulaBoolValue immediately (not in this
patch, to isolate changes). For AtomicBoolValue we first need to update
clients to stop using value pointers for atom identity.

The data structures around flow conditions are updated:
- flow condition tokens are Atom, rather than AtomicBoolValue*
- conditions are Formula, rather than BoolValue
Most APIs were changed directly, some with many clients had a
new version added and the existing one deprecated.

The factories for BoolValues in Environment keep their existing
signatures for now (e.g. makeOr(BoolValue, BoolValue) => BoolValue)
and are not deprecated. These have very many clients and finding the
most ergonomic API & migration path still needs some thought.

Differential Revision: https://reviews.llvm.org/D153469

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Revert "Reland "[dataflow] Add dedicated representation of boolean formulas" and followups

These changes are OK, but they break downstream stuff that needs more time to adapt :-(

This reverts commi

Revert "Reland "[dataflow] Add dedicated representation of boolean formulas" and followups

These changes are OK, but they break downstream stuff that needs more time to adapt :-(

This reverts commit 71579569f4399d3cf6bc618dcd449b5388d749cc.
This reverts commit 5e4ad816bf100b0325ed45ab1cfea18deb3ab3d1.
This reverts commit 1c3ac8dfa16c42a631968aadd0396cfe7f7778e0.

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[dataflow] Replace most BoolValue subclasses with references to Formula (and AtomicBoolValue => Atom and BoolValue => Formula where appropriate)

This properly frees the Value hierarchy from managing

[dataflow] Replace most BoolValue subclasses with references to Formula (and AtomicBoolValue => Atom and BoolValue => Formula where appropriate)

This properly frees the Value hierarchy from managing boolean formulas.

We still distinguish AtomicBoolValue; this type is used in client code.
However we expect to convert such uses to BoolValue (where the
distinction is not needed) or Atom (where atomic identity is intended),
and then fold AtomicBoolValue into FormulaBoolValue.

We also distinguish TopBoolValue; this has distinct rules for
widen/join/equivalence, and top-ness is not represented in Formula.
It'd be nice to find a cleaner representation (e.g. the absence of a
formula), but no immediate plans.

For now, BoolValues with the same Formula are deduplicated. This doesn't
seem desirable, as Values are mutable by their creators (properties).
We can probably drop this for FormulaBoolValue immediately (not in this
patch, to isolate changes). For AtomicBoolValue we first need to update
clients to stop using value pointers for atom identity.

The data structures around flow conditions are updated:
- flow condition tokens are Atom, rather than AtomicBoolValue*
- conditions are Formula, rather than BoolValue
Most APIs were changed directly, some with many clients had a
new version added and the existing one deprecated.

The factories for BoolValues in Environment keep their existing
signatures for now (e.g. makeOr(BoolValue, BoolValue) => BoolValue)
and are not deprecated. These have very many clients and finding the
most ergonomic API & migration path still needs some thought.

Differential Revision: https://reviews.llvm.org/D153469

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[clang][dataflow] Add equivalence relation `Value` type.

Defines an equivalence relation on the `Value` type to standardize several
places in the code where we replicate the ~same equivalence compar

[clang][dataflow] Add equivalence relation `Value` type.

Defines an equivalence relation on the `Value` type to standardize several
places in the code where we replicate the ~same equivalence comparison.

Differential Revision: https://reviews.llvm.org/D135964

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