This reverts commit 7c51f02eff because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.
Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.
The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.
An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.
---
Troubleshooting list to deal with any breakage seen with this patch:
1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.
2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.
3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.
4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.
5) It could be a bug in this patch perhaps.
Let me know if you need any help!
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D112374
We consider an access to x.*pm as access of the same kind into x, and
an access to px->*pm as access of the same kind into *px. Previously we
missed reads and writes in the .* case, and operations to the pointed-to
data for ->* (we didn't miss accesses to the pointer itself, because
that requires an LValueToRValue cast that we treat independently).
We added support for overloaded operator->* in D124966.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D129514
This reverts commit bdc6974f92 because it
breaks all the LLDB tests that import the std module.
import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py
https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/
Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.
The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.
An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D112374
This reverts commit 19e21887eb. I
accidentally landed the non-final version of the patch that used
decomposition declarations (not yet usable in LLVM/Clang source).
A truth assignment to atomic boolean values which satisfy `Constraints` will be returned if found by the solver.
This gives us more information which can be helpful for debugging or constructing warning messages.
Reviewed By: hlopko, gribozavr2, sgatev
Differential Revision: https://reviews.llvm.org/D129180
Treat `std::nullptr_t` as a regular scalar type to avoid tripping
assertions when analyzing code that uses `std::nullptr_t`.
Differential Revision: https://reviews.llvm.org/D129097
This is a recommit of b822efc740,
reverted in dc34d8df4c. The commit caused
fails because the test ast-print-fp-pragmas.c did not specify particular
target, and it failed on targets which do not support constrained
intrinsics. The original commit message is below.
AST does not have special nodes for pragmas. Instead a pragma modifies
some state variables of Sema, which in turn results in modified
attributes of AST nodes. This technique applies to floating point
operations as well. Every AST node that can depend on FP options keeps
current set of them.
This technique works well for options like exception behavior or fast
math options. They represent instructions to the compiler how to modify
code generation for the affected nodes. However treatment of FP control
modes has problems with this technique. Modifying FP control mode
(like rounding direction) usually requires operations on hardware, like
writing to control registers. It must be done prior to the first
operation that depends on the control mode. In particular, such
operations are required for implementation of `pragma STDC FENV_ROUND`,
compiler should set up necessary rounding direction at the beginning of
compound statement where the pragma occurs. As there is no representation
for pragmas in AST, the code generation becomes a complicated task in
this case.
To solve this issue FP options are kept inside CompoundStmt. Unlike to FP
options in expressions, these does not affect any operation on FP values,
but only inform the codegen about the FP options that act in the body of
the statement. As all pragmas that modify FP environment may occurs only
at the start of compound statement or at global level, such solution
works for all relevant pragmas. The options are kept as a difference
from the options in the enclosing compound statement or default options,
it helps codegen to set only changed control modes.
Differential Revision: https://reviews.llvm.org/D123952
AST does not have special nodes for pragmas. Instead a pragma modifies
some state variables of Sema, which in turn results in modified
attributes of AST nodes. This technique applies to floating point
operations as well. Every AST node that can depend on FP options keeps
current set of them.
This technique works well for options like exception behavior or fast
math options. They represent instructions to the compiler how to modify
code generation for the affected nodes. However treatment of FP control
modes has problems with this technique. Modifying FP control mode
(like rounding direction) usually requires operations on hardware, like
writing to control registers. It must be done prior to the first
operation that depends on the control mode. In particular, such
operations are required for implementation of `pragma STDC FENV_ROUND`,
compiler should set up necessary rounding direction at the beginning of
compound statement where the pragma occurs. As there is no representation
for pragmas in AST, the code generation becomes a complicated task in
this case.
To solve this issue FP options are kept inside CompoundStmt. Unlike to FP
options in expressions, these does not affect any operation on FP values,
but only inform the codegen about the FP options that act in the body of
the statement. As all pragmas that modify FP environment may occurs only
at the start of compound statement or at global level, such solution
works for all relevant pragmas. The options are kept as a difference
from the options in the enclosing compound statement or default options,
it helps codegen to set only changed control modes.
Differential Revision: https://reviews.llvm.org/D123952
Fixing issue "incorrect -Winfinite-recursion warning on potentially-
unevaluated operand".
We add a dedicated visit function (VisitCXXTypeidExpr) for typeid,
instead of using the default (VisitStmt). In this new function we skip
over building the CFG for unevaluated operands of typeid.
Fixes#21668
Differential Revision: https://reviews.llvm.org/D128747
This patch deletes the now-unused `SourceLocationsLattice` class, along with its containing files and surrounding helper functions and tests.
Reviewed By: xazax.hun, ymandel, sgatev, gribozavr2
Differential Revision: https://reviews.llvm.org/D128448
Followup to D128352. This patch pulls the `NoopLattice` class out from the `NoopAnalysis.h` test file into its own `NoopLattice.h` source file, and uses it to replace usage of `SourceLocationsLattice` in `UncheckedOptionalAccessModel`.
Reviewed By: ymandel, sgatev, gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D128356
Followup to D128352. This patch pulls the `NoopLattice` class out from the `NoopAnalysis.h` test file into its own `NoopLattice.h` source file, and uses it to replace usage of `SourceLocationsLattice` in `UncheckedOptionalAccessModel`.
Reviewed By: ymandel, sgatev, gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D128356
This patch adds an optional `PostVisitStmt` parameter to the `runTypeErasedDataflowAnalysis` function, which does one more pass over all statements in the CFG after a fixpoint is reached. It then defines a `diagnose` method for the optional model in a new `UncheckedOptionalAccessDiagnosis` class, but only integrates that into the tests and not the actual optional check for `clang-tidy`. That will be done in a followup patch.
The primary motivation is to separate the implementation of the unchecked optional access check into two parts, to allow for further refactoring of just the model part later, while leaving the checking part alone. Currently there is duplication between the `transferUnwrapCall` and `diagnoseUnwrapCall` functions, but that will be dealt with in the followup.
Because diagnostics are now all gathered into one collection rather than being populated at each program point like when computing a fixpoint, this patch removes the usage of `Pair` and `UnorderedElementsAre` from the optional model tests, and instead modifies all their expectations to simply check the stringified set of diagnostics against a single string, either `"safe"` or some concatenation of `"unsafe: input.cc:y:x"`. This is not ideal as it loses any connection to the `/*[[check]]*/` annotations in the source strings, but it does still retain the source locations from the diagnostic strings themselves.
Reviewed By: sgatev, gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D127898
When a `nullptr` is assigned to a pointer variable, it is wrapped in a `ImplicitCastExpr` with cast kind `CK_NullTo(Member)Pointer`. This patch assigns singleton pointer values representing null to these expressions.
For each pointee type, a singleton null `PointerValue` is created and stored in the `NullPointerVals` map of the `DataflowAnalysisContext` class. The pointee type is retrieved from the implicit cast expression, and used to initialise the `PointeeLoc` field of the `PointerValue`. The `PointeeLoc` created is not mapped to any `Value`, reflecting the absence of value indicated by null pointers.
Reviewed By: gribozavr2, sgatev, xazax.hun
Differential Revision: https://reviews.llvm.org/D128056
This patch introduces `buildAndSubstituteFlowCondition` - given a flow condition token, this function returns the expression of constraints defining the flow condition, with values substituted where specified.
As an example:
Say we have tokens `FC1`, `FC2`, `FC3`:
```
FlowConditionConstraints: {
FC1: C1,
FC2: C2,
FC3: (FC1 v FC2) ^ C3,
}
```
`buildAndSubstituteFlowCondition(FC3, /*Substitutions:*/{{C1 -> C1'}})`
returns a value corresponding to `(C1' v C2) ^ C3`.
Note:
This function returns the flow condition expressed directly as its constraints, which differs to how we currently represent the flow condition as a token bound to a set of constraints and dependencies. Making the representation consistent may be an option to consider in the future.
Depends On D128357
Reviewed By: gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D128363
`createStorageLocation` in `DataflowEnvironment` is now a trivial wrapper around the logic in `DataflowAnalysisContext`.
Additionally, `getObjectFields` and `getFieldsFromClassHierarchy` (required for the implementation of `createStorageLocation`) are also moved to `DataflowAnalysisContext`.
Reviewed By: gribozavr2, sgatev
Differential Revision: https://reviews.llvm.org/D128359
`equivalentBoolValues` compares equivalence between two booleans. The current implementation does not consider constraints imposed by flow conditions on the booleans and its subvalues.
Depends On D128520
Reviewed By: gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D128521
Given a set of `Constraints`, `querySolver` adds common background information across queries (`TrueVal` is always true and `FalseVal` is always false) and passes the query to the solver.
`checkUnsatisfiable` is a simple wrapper around `querySolver` for checking that the solver returns an unsatisfiable result.
Depends On D128519
Reviewed By: gribozavr2, xazax.hun
Differential Revision: https://reviews.llvm.org/D128520
To keep functionality of creating boolean expressions in a consistent location.
Depends On D128357
Reviewed By: gribozavr2, sgatev, xazax.hun
Differential Revision: https://reviews.llvm.org/D128519
A flow condition is represented with an atomic boolean token, and it is bound to a set of constraints: `(FC <=> C1 ^ C2 ^ ...)`. \
This was internally represented as `(FC v !C1 v !C2 v ...) ^ (C1 v !FC) ^ (C2 v !FC) ^ ...` and tracked by 2 maps:
- `FlowConditionFirstConjunct` stores the first conjunct `(FC v !C1 v !C2 v ...)`
- `FlowConditionRemainingConjuncts` stores the remaining conjuncts `(C1 v !FC) ^ (C2 v !FC) ^ ...`
This patch simplifies the tracking of the constraints by using a single `FlowConditionConstraints` map which stores `(C1 ^ C2 ^ ...)`, eliminating the use of two maps.
Reviewed By: gribozavr2, sgatev, xazax.hun
Differential Revision: https://reviews.llvm.org/D128357
For DecompositionDecl, the array, which is being decomposed was not present in the
CFG, which lead to the liveness analysis falsely detecting it as a dead symbol.
Differential Revision: https://reviews.llvm.org/D127993
Add support for correlated branches to the std::optional dataflow model.
Differential Revision: https://reviews.llvm.org/D125931
Reviewed-by: ymandel, xazax.hun
We distinguish between the referent location for `ReferenceValue` and pointee location for `PointerValue`. The former must be non-empty but the latter may be empty in the case of a `nullptr`
Reviewed By: gribozavr2, sgatev
Differential Revision: https://reviews.llvm.org/D127745
Currently the unchecked-optional-access model fails on this example:
#include <memory>
#include <optional>
void foo() {
std::unique_ptr<std::optional<float>> x;
*x = std::nullopt;
}
You can verify the failure by saving the file as `foo.cpp` and running this command:
clang-tidy -checks='-*,bugprone-unchecked-optional-access' foo.cpp -- -std=c++17
The failing `assert` is in the `transferAssignment` function of the `UncheckedOptionalAccessModel.cpp` file:
assert(OptionalLoc != nullptr);
The symptom can be treated by replacing that `assert` with an early `return`:
if (OptionalLoc == nullptr)
return;
That would be better anyway since we cannot expect to always cover all possible LHS expressions, but it is out of scope for this patch and left as a followup.
Note that the failure did not occur on this very similar example:
#include <optional>
template <typename T>
struct smart_ptr {
T& operator*() &;
T* operator->();
};
void foo() {
smart_ptr<std::optional<float>> x;
*x = std::nullopt;
}
The difference is caused by the `isCallReturningOptional` matcher, which was previously checking the `functionDecl` of the `callee`. This patch changes it to instead use `hasType` directly on the call expression, fixing the failure for the `std::unique_ptr` example above.
Reviewed By: sgatev
Differential Revision: https://reviews.llvm.org/D127434
This patch adds partial support for tracking (i.e. modeling) the contents of an
optional value. Specifically, it supports tracking the value after it is
accessed. We leave tracking constructed/assigned contents to a future patch.
Differential Revision: https://reviews.llvm.org/D124932
co_await and co_yield are represented by (classes derived from)
CoroutineSuspendExpr. That has a number of child nodes, not all of
which are used for code-generation. In particular the operand is
represented multiple times, and, like the problem with co_return
(55406) it must only be emitted in the CFG exactly once. The operand
also appears inside OpaqueValueExprs, but that's ok.
This adds a visitor for SuspendExprs to emit the required children in
the correct order. Note that this CFG is pre-coro xform. We don't
have initial or final suspend points.
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D127236
This patch precedes a future patch to make PointeeLoc for PointerValue possibly empty (for nullptr), by using a pointer instead of a reference type.
ReferenceValue should maintain a non-empty PointeeLoc reference.
Reviewed By: gribozavr2
Differential Revision: https://reviews.llvm.org/D127312
This patch moves the implementation of synthetic properties from the StructValue class into the Value base class so that it can be used across all Value instances.
Reviewed By: gribozavr2, ymandel, sgatev, xazax.hun
Differential Revision: https://reviews.llvm.org/D127196
Previously, type aliases were not handled (and resulted in an assertion
firing). This patch generalizes the model to consider aliases everywhere (a
previous patch already considered aliases for optional-returning functions).
Differential Revision: https://reviews.llvm.org/D126972
Jonas Devlieghere