This is a major change on how we represent nested name qualifications in
the AST.
* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.
This patch offers a great performance benefit.
It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.
This has great results on compile-time-tracker as well:
This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.
It has some other miscelaneous drive-by fixes.
About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.
There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.
How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.
The rest and bulk of the changes are mostly consequences of the changes
in API.
PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.
Fixes#136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
Closes#57270.
This PR changes the `Stmt *` field in `SymbolConjured` with
`CFGBlock::ConstCFGElementRef`. The motivation is that, when conjuring a
symbol, there might not always be a statement available, causing
information to be lost for conjured symbols, whereas the CFGElementRef
can always be provided at the callsite.
Following the idea, this PR changes callsites of functions to create
conjured symbols, and replaces them with appropriate `CFGElementRef`s.
There is a caveat at loop widening, where the correct location is the
CFG terminator (which is not an element and does not have a ref). In
this case, the first element in the block is passed as a location.
Previous PR #128251, Reverted at #137304.
Per suggestion in
https://github.com/llvm/llvm-project/pull/128251#discussion_r2055916229,
adding a new helper function in `SValBuilder` to conjure a symbol when
given a `CallEvent`.
Tested manually (with assertions) that the `LocationContext *` obtained
from the `CallEvent` are identical to those passed in the original
argument.
This PR changes the `Stmt *` field in `SymbolConjured` with
`CFGBlock::ConstCFGElementRef`. The motivation is that, when conjuring a
symbol, there might not always be a statement available, causing
information to be lost for conjured symbols, whereas the CFGElementRef
can always be provided at the callsite.
Following the idea, this PR changes callsites of functions to create
conjured symbols, and replaces them with appropriate `CFGElementRef`s.
Closes#57270
Introduce a trait to determine the number of bindings that would be
produced by
```cpp
auto [...p] = expr;
```
This is necessary to implement P2300
(https://eel.is/c++draft/exec#snd.concepts-5), but can also be used to
implement a general get<N> function that supports aggregates
`__builtin_structured_binding_size` is a unary type trait that evaluates
to the number of bindings in a decomposition
If the argument cannot be decomposed, a sfinae-friendly error is
produced.
A type is considered a valid tuple if `std::tuple_size_v<T>` is a valid
expression, even if there is no valid `std::tuple_element`
specialization or suitable `get` function for that type.
Fixes#46049
Ideally, we wouldn't workaround our current cast-modeling, but the
experimental "support-symbolic-integer-casts" is not finished so we need
to live with our current modeling.
Ideally, we could probably bind `UndefinedVal` as the result of the call
even without evaluating the call, as the result types mismatch between
the static type of the `CallExpr` and the actually function that happens
to be called.
Nevertheless, let's not crash.
https://compiler-explorer.com/z/WvcqK6MbY
CPP-5768
As was reported
[here](https://github.com/llvm/llvm-project/pull/103714#pullrequestreview-2238037812),
`invalidateRegions` should accept `Stmt` instead of `Expr`. This
conversion is possible, since `Expr` was anyway converted back to `Stmt`
later.
This refactoring is needed to fix another FP related to use of inline
assembly. The fix would be to change `State->bindLoc` to
`state->invalidateRegions` inside inline assembly visitor, since
`bindLoc` only binds to offset 0, which is not really correct semantics
in case of inline assembly.
PR refactors `MallocChecker` to not violate invariant of `BindExpr`,
which should be called only during `evalCall` to avoid conflicts.
To achieve this, most of `postCall` logic was moved to `evalCall` with
addition return value binding in case of processing of allocation
functions. Check functions prototypes was changed to use `State` with
bound return value.
`checkDelim` logic was left in `postCall` to avoid conflicts with
`StreamChecker` which also evaluates `getline` and friends.
PR also introduces breaking change in the unlikely case when the
definition of an allocation function (e.g. `malloc()`) is visible: now
checker does not try to inline allocation functions and assumes their
initial semantics.
Closes#73830
...to model the results of alloca() and _alloca() calls. Previously it
acted as if these functions were returning memory from the heap, which
led to alpha.security.ArrayBoundV2 producing incorrect messages.
The goal of this patch is to refine how the `SVal` base and sub-kinds
are represented by forming one unified enum describing the possible
SVals. This means that the `unsigned SVal::Kind` and the attached
bit-packing semantics would be replaced by a single unified enum. This
is more conventional and leads to a better debugging experience by
default. This eases the need of using debug pretty-printers, or the use
of runtime functions doing the printing for us like we do today by
calling `Val.dump()` whenever we inspect the values.
Previously, the first 2 bits of the `unsigned SVal::Kind` discriminated
the following quartet: `UndefinedVal`, `UnknownVal`, `Loc`, or `NonLoc`.
The rest of the upper bits represented the sub-kind, where the value
represented the index among only the `Loc`s or `NonLoc`s, effectively
attaching 2 meanings of the upper bits depending on the base-kind. We
don't need to pack these bits, as we have plenty even if we would use
just a plan-old `unsigned char`.
Consequently, in this patch, I propose to lay out all the (non-abstract)
`SVal` kinds into a single enum, along with some metadata (`BEGIN_Loc`,
`END_Loc`, `BEGIN_NonLoc`, `END_NonLoc`) artificial enum values, similar
how we do with the `MemRegions`.
Note that in the unified `SVal::Kind` enum, to differentiate
`nonloc::ConcreteInt` from `loc::ConcreteInt`, I had to prefix them with
`Loc` and `NonLoc` to resolve this ambiguity.
This should not surface in general, because I'm replacing the
`nonloc::Kind` enum items with `inline constexpr` global constants to
mimic the original behavior - and offer nicer spelling to these enum
values.
Some `SVal` constructors were not marked explicit, which I now mark as
such to follow best practices, and marked others as `/*implicit*/` to
clarify the intent.
During refactoring, I also found at least one function not marked
`LLVM_ATTRIBUTE_RETURNS_NONNULL`, so I did that.
The `TypeRetrievingVisitor` visitor had some accidental dead code,
namely: `VisitNonLocConcreteInt` and `VisitLocConcreteInt`.
Previously, the `SValVisitor` expected visit handlers of
`VisitNonLocXXXXX(nonloc::XXXXX)` and `VisitLocXXXXX(loc::XXXXX)`, where
I felt that envoding `NonLoc` and `Loc` in the name is not necessary as
the type of the parameter would select the right overload anyways, so I
simplified the naming of those visit functions.
The rest of the diff is a lot of times just formatting, because
`getKind()` by nature, frequently appears in switches, which means that
the whole switch gets automatically reformatted. I could probably undo
the formatting, but I didn't want to deviate from the rule unless
explicitly requested.
Workaround the case when the `this` pointer is actually a `NonLoc`, by
returning `Unknown` instead.
The solution isn't ideal, as `this` should be really a `Loc`, but due to
how casts work, I feel this is our easiest and best option.
As this patch presents, I'm evaluating a cast to transform the `NonLoc`.
However, given that `evalCast()` can't be cast from `NonLoc` to a
pointer type thingy (`Loc`), we end up with `Unknown`.
It is because `EvalCastVisitor::VisitNonLocSymbolVal()` only evaluates
casts that happen from NonLoc to NonLocs.
When I tried to actually implement that case, I figured:
1) Create a `SymbolicRegion` from that `nonloc::SymbolVal`; but
`SymbolRegion` ctor expects a pointer type for the symbol.
2) Okay, just have a `SymbolCast`, getting us the pointer type; but
`SymbolRegion` expects `SymbolData` symbols, not generic `SymExpr`s, as
stated:
> // Because pointer arithmetic is represented by ElementRegion layers,
> // the base symbol here should not contain any arithmetic.
3) We can't use `ElementRegion`s to perform this cast because to have an
`ElementRegion`, you already have to have a `SubRegion` that you want to
cast, but the point is that we don't have that.
At this point, I gave up, and just left a FIXME instead, while still
returning `Unknown` on that path.
IMO this is still better than having a crash.
Fixes#69922
evalIntegralCast was using makeIntVal, and when _BitInt() types were
introduced this exposed a crash in evalIntegralCast as a result.
This is a reapply of a previous patch that failed post merge on the arm
buildbots, because arm cannot handle large
BitInts. Pinning the triple for the testcase solves that problem.
Improve evalIntegralCast to use makeIntVal more efficiently to avoid the
crash exposed by use of _BitInt.
This was caught with our internal randomized testing.
<src-root>/llvm/include/llvm/ADT/APInt.h:1510:
int64_t llvm::APInt::getSExtValue() const: Assertion
`getSignificantBits() <= 64 && "Too many bits for int64_t"' failed.a
...
#9 <address> llvm::APInt::getSExtValue() const
<src-root>/llvm/include/llvm/ADT/APInt.h:1510:5
llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>,
clang::ento::SVal, clang::QualType, clang::QualType)
<src-root>/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp:607:24
clang::Expr const*, clang::ento::ExplodedNode*,
clang::ento::ExplodedNodeSet&)
<src-root>/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp:413:61
...
Fixes: https://github.com/llvm/llvm-project/issues/61960
Reviewed By: donat.nagy
This reverts commit 4898c33527f90b067f353a115442a9a702319fce.
Lots of buildbots are failing, probably because lots of targets not supporting
large _BitInt types.
evalIntegralCast was using makeIntVal, and when _BitInt() types were
introduced this exposed a crash in evalIntegralCast as a result.
Improve evalIntegralCast to use makeIntVal more efficiently to avoid the
crash exposed by use of _BitInt.
This was caught with our internal randomized testing.
<src-root>/llvm/include/llvm/ADT/APInt.h:1510:
int64_t llvm::APInt::getSExtValue() const: Assertion
`getSignificantBits() <= 64 && "Too many bits for int64_t"' failed.a
...
#9 <address> llvm::APInt::getSExtValue() const
<src-root>/llvm/include/llvm/ADT/APInt.h:1510:5
llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>,
clang::ento::SVal, clang::QualType, clang::QualType)
<src-root>/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp:607:24
clang::Expr const*, clang::ento::ExplodedNode*,
clang::ento::ExplodedNodeSet&)
<src-root>/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp:413:61
...
Fixes: https://github.com/llvm/llvm-project/issues/61960
Reviewed By: donat.nagy
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Summary: Get rid of explicit function splitting in favor of specifically designed Visitor. Move logic from a family of `evalCastKind` and `evalCastSubKind` helper functions to `SValVisitor`.
Differential Revision: https://reviews.llvm.org/D130029
Depends on D128068.
Added a new test code that fails an assertion in the baseline.
That is because `getAPSIntType` works only with integral types.
Differential Revision: https://reviews.llvm.org/D126779
In `RegionStore::getBinding` we call `evalCast` unconditionally to align
the stored value's type to the one that is being queried. However, the
stored type might be the same, so we may end up having redundant
`SymbolCasts` emitted.
The solution is to check whether the `to` and `from` type are the same
in `makeNonLoc`.
Note, we can't just do type equivalence check at the beginning of `evalCast`
because when `evalCast` is called from `getBinding` then the original type
(`OriginalTy`) is not set, so one operand is missing for the comparison. In
`evalCastSubKind(nonloc::SymbolVal)` when the original type is not set,
we get the `from` type via `SymbolVal::getType()`.
Differential Revision: https://reviews.llvm.org/D128068
This is an initial step of removing the SimpleSValBuilder abstraction. The SValBuilder alone should be enough.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D126127
This patch adds a new descendant to the SymExpr hierarchy. This way, now
we can assign constraints to symbolic unary expressions. Only the unary
minus and bitwise negation are handled.
Differential Revision: https://reviews.llvm.org/D125318
We ignored the cast if the enum was scoped.
This is bad since there is no implicit conversion from the scoped enum to the corresponding underlying type.
The fix is basically: isIntegralOrEnumerationType() -> isIntegralOr**Unscoped**EnumerationType()
This materialized in crashes on analyzing the LLVM itself using the Z3 refutation.
Refutation synthesized the given Z3 Binary expression (`BO_And` of `unsigned char` aka. 8 bits
and an `int` 32 bits) with the wrong bitwidth in the end, which triggered an assert.
Now, we evaluate the cast according to the standard.
This bug could have been triggered using the Z3 CM according to
https://bugs.llvm.org/show_bug.cgi?id=44030Fixes#47570#43375
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D85528
clang: <root>/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp:727:
void assertEqualBitWidths(clang::ento::ProgramStateRef,
clang::ento::Loc, clang::ento::Loc): Assertion `RhsBitwidth ==
LhsBitwidth && "RhsLoc and LhsLoc bitwidth must be same!"'
This change adjusts the bitwidth of the smaller operand for an evalBinOp
as a result of a comparison operation. This can occur in the specific
case represented by the test cases for a target with different pointer
sizes.
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D122513
This is a NFC refactoring to change makeIntValWithPtrWidth
and remove getZeroWithPtrWidth to use types when forming values to match
pointer widths. Some targets may have different pointer widths depending
upon address space, so this needs to be comprehended.
Reviewed By: steakhal
Differential Revision: https://reviews.llvm.org/D120134
Usages of makeNull need to be deprecated in favor of makeNullWithWidth
for architectures where the pointer size should not be assumed. This can
occur when pointer sizes can be of different sizes, depending on address
space for example. See https://reviews.llvm.org/D118050 as an example.
This was uncovered initially in a downstream compiler project, and
tested through those systems tests.
steakhal performed systems testing across a large set of open source
projects.
Co-authored-by: steakhal
Resolves: https://github.com/llvm/llvm-project/issues/53664
Reviewed By: NoQ, steakhal
Differential Revision: https://reviews.llvm.org/D119601
Summary: Produce SymbolCast for integral types in `evalCast` function. Apply several simplification techniques while producing the symbols. Added a boolean option `handle-integral-cast-for-ranges` under `-analyzer-config` flag. Disabled the feature by default.
Differential Revision: https://reviews.llvm.org/D105340
Previously, the `SValBuilder` could not encounter expressions of the
following kind:
NonLoc OP Loc
Loc OP NonLoc
Where the `Op` is other than `BO_Add`.
As of now, due to the smarter simplification and the fixedpoint
iteration, it turns out we can.
It can happen if the `Loc` was perfectly constrained to a concrete
value (`nonloc::ConcreteInt`), thus the simplifier can do
constant-folding in these cases as well.
Unfortunately, this could cause assertion failures, since we assumed
that the operator must be `BO_Add`, causing a crash.
---
In the patch, I decided to preserve the original behavior (aka. swap the
operands (if the operator is commutative), but if the `RHS` was a
`loc::ConcreteInt` call `evalBinOpNN()`.
I think this interpretation of the arithmetic expression is closer to
reality.
I also tried naively introducing a separate handler for
`loc::ConcreteInt` RHS, before doing handling the more generic `Loc` RHS
case. However, it broke the `zoo1backwards()` test in the `nullptr.cpp`
file. This highlighted for me the importance to preserve the original
behavior for the `BO_Add` at least.
PS: Sorry for introducing yet another branch into this `evalBinOpXX`
madness. I've got a couple of ideas about refactoring these.
We'll see if I can get to it.
The test file demonstrates the issue and makes sure nothing similar
happens. The `no-crash` annotated lines show, where we crashed before
applying this patch.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D115149
It turns out llvm::isa<> is variadic, and we could have used this at a
lot of places.
The following patterns:
x && isa<T1>(x) || isa<T2>(x) ...
Will be replaced by:
isa_and_non_null<T1, T2, ...>(x)
Sometimes it caused further simplifications, when it would cause even
more code smell.
Aside from this, keep in mind that within `assert()` or any macro
functions, we need to wrap the isa<> expression within a parenthesis,
due to the parsing of the comma.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D111982
`SVB.getStateManager().getOwningEngine().getAnalysisManager().getAnalyzerOptions()`
is quite a mouthful and might involve a few pointer indirections to get
such a simple thing like an analyzer option.
This patch introduces an `AnalyzerOptions` reference to the `SValBuilder`
abstract class, while refactors a few cases to use this /simpler/ accessor.
Reviewed By: martong, Szelethus
Differential Revision: https://reviews.llvm.org/D108824
This change follows up on a FIXME submitted with D105974. This change simply let's the reference case fall through to return a concrete 'true'
instead of a nonloc pointer of appropriate length set to NULL.
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D107720
This change addresses this assertion that occurs in a downstream
compiler with a custom target.
```APInt.h:1151: bool llvm::APInt::operator==(const llvm::APInt &) const: Assertion `BitWidth == RHS.BitWidth && "Comparison requires equal bit widths"'```
No covering test case is susbmitted with this change since this crash
cannot be reproduced using any upstream supported target. The test case
that exposes this issue is as simple as:
```lang=c++
void test(int * p) {
int * q = p-1;
if (q) {}
if (q) {} // crash
(void)q;
}
```
The custom target that exposes this problem supports two address spaces,
16-bit `char`s, and a `_Bool` type that maps to 16-bits. There are no upstream
supported targets with similar attributes.
The assertion appears to be happening as a result of evaluating the
`SymIntExpr` `(reg_$0<int * p>) != 0U` in `VisitSymIntExpr` located in
`SimpleSValBuilder.cpp`. The `LHS` is evaluated to `32b` and the `RHS` is
evaluated to `16b`. This eventually leads to the assertion in `APInt.h`.
While this change addresses the crash and passes LITs, two follow-ups
are required:
1) The remainder of `getZeroWithPtrWidth()` and `getIntWithPtrWidth()`
should be cleaned up following this model to prevent future
confusion.
2) We're not sure why references are found along with the modified
code path, that should not be the case. A more principled
fix may be found after some further comprehension of why this
is the case.
Acks: Thanks to @steakhal and @martong for the discussions leading to this
fix.
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D105974
Summary: Replaced code on region cast with a function-wrapper SValBuilder::getCastedMemRegionVal. This is a next step of code refining due to suggestions in D103319.
Differential Revision: https://reviews.llvm.org/D103803
Summary: Make StoreManager::castRegion function usage safier. Replace `const MemRegion *` with `Optional<const MemRegion *>`. Simplified one of related test cases due to suggestions in D101635.
Differential Revision: https://reviews.llvm.org/D103319
