19 Commits

Author SHA1 Message Date
martinboehme
834cb919b3
[clang][dataflow] Remove declarations from DeclToLoc when their lifetime ends. (#67300)
After https://reviews.llvm.org/D153273, we're now able to use
`CFGLifetimeEnds`
together with the other CFG options we use.
2023-09-26 08:41:09 +02:00
martinboehme
c0703eaec1
[clang][dataflow] Emit an error if source code is not compiled as C++. (#65301)
The shape of certain elements of the AST can vary depending on the
langugage.
We currently only support C++.
2023-09-06 10:02:21 +02:00
Martin Braenne
bf46b0b551 [clang][dataflow] Eliminate deprecated ControlFlowContext::build() overload.
Reviewed By: ymandel, xazax.hun

Differential Revision: https://reviews.llvm.org/D159262
2023-09-04 08:30:54 +00:00
Martin Braenne
e6cd409fc6 [clang][dataflow] In ControlFlowContext, handle Decl by reference instead of pointer.
`build()` guarantees that we'll always have a `Decl`, so we can simplify the code.

Reviewed By: ymandel, xazax.hun

Differential Revision: https://reviews.llvm.org/D156859
2023-08-03 06:59:29 +00:00
Martin Braenne
5ddb623952 [clang][dataflow] Remove unnecessary ASTContext parameter from ControlFlowContext::build overload.
When introducing this new overload in https://reviews.llvm.org/D151183, I didn't consider that the `ASTContext` parameter was unnecessary because it could also be obtained from the `FunctionDecl`.

Reviewed By: gribozavr2, xazax.hun

Differential Revision: https://reviews.llvm.org/D151549
2023-05-30 07:05:35 +00:00
Martin Braenne
246626a8cf [clang][dataflow] Add a ControlFlowContext::build() overload taking a FunctionDecl.
This is the most common use case, so it makes sense to have a specific overload for it.

Reviewed By: xazax.hun

Differential Revision: https://reviews.llvm.org/D151183
2023-05-25 07:19:12 +00:00
Martin Braenne
1a42f79558 [clang][dataflow] Don't analyze templated declarations.
Attempting to analyze templated code doesn't have a good cost-benefit ratio. We
have so far done a best-effort attempt at this, but maintaining this support has
an ongoing high maintenance cost because the AST for templates can violate a lot
of the invariants that otherwise hold for the AST of concrete code. As just one
example, in concrete code the operand of a UnaryOperator '*' is always a prvalue
(https://godbolt.org/z/s3e5xxMd1), but in templates this isn't true
(https://godbolt.org/z/6W9xxGvoM).

Further rationale for not analyzing templates:

* The semantics of a template itself are weakly defined; semantics can depend
  strongly on the concrete template arguments. Analyzing the template itself (as
  opposed to an instantiation) therefore has limited value.

* Analyzing templates requires a lot of special-case code that isn't necessary
  for concrete code because dependent types are hard to deal with and the AST
  violates invariants that otherwise hold for concrete code (see above).

* There's precedent in that neither Clang Static Analyzer nor the flow-sensitive
  warnings in Clang (such as uninitialized variables) support analyzing
  templates.

Reviewed By: gribozavr2, xazax.hun

Differential Revision: https://reviews.llvm.org/D150352
2023-05-15 11:04:51 +00:00
Kinuko Yasuda
791b0fd026 [clang][dataflow] Change PruneTriviallyFalseEdges for building CFG
Keeping this false could end up with extra iterations on a lot of loops
that aren't real ones (e.g. they could be a do-while-false for macros),
and makes the analyses very slow.

This patch changes the default for
CFG::BuildOptions.PruneTriviallyFalseEdges to true to avoid it.

Reviewed By: ymandel, xazax.hun, gribozavr2

Differential Revision: https://reviews.llvm.org/D149640
2023-05-03 18:42:15 +00:00
Martin Braenne
5acd29eb4d [clang][dataflow] Fix crash when RHS of && or || calls noreturn func.
The crash happened because the transfer fucntion for `&&` and `||`
unconditionally tried to retrieve the value of the RHS. However, if the RHS
is unreachable, there is no environment for it, and trying to retrieve the
operand's value causes an assertion failure.

See also the comments in the code for further details.

Reviewed By: xazax.hun, ymandel, sgatev, gribozavr2

Differential Revision: https://reviews.llvm.org/D146514
2023-03-23 08:02:43 +00:00
Dmitri Gribenko
d27386384a [clang] Remove deprecated ControlFlowContext::build()
Reviewed By: merrymeerkat

Differential Revision: https://reviews.llvm.org/D140625
2022-12-23 15:06:59 +01:00
Fangrui Song
1e6adbadc7 [clang] llvm::Optional::value => operator*/operator->
std::optional::value() has undesired exception checking semantics and is
unavailable in older Xcode (see _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS). The
call sites block std::optional migration.

This makes `ninja check-clang` work in the absence of llvm::Optional::value.
2022-12-17 08:10:45 +00:00
Yitzhak Mandelbaum
692e03039d [clang][dataflow] Add cache of ControlFlowContexts for function decls.
This patch modifies context-sensitive analysis of functions to use a cache,
rather than recreate the `ControlFlowContext` from a function decl on each
encounter. However, this is just step 1 (of N) in adding support for a
configurable map of "modeled" function decls (see issue #56879). The map will go
from the actual function decl to the `ControlFlowContext` used to model it. Only
functions pre-configured in the map will be modeled in a context-sensitive way.

We start with a cache because it introduces the desired map, while retaining the
current behavior. Here, functions are mapped to their actual implementations
(when available).

Differential Revision: https://reviews.llvm.org/D131039
2022-08-03 15:17:49 +00:00
Kazu Hirata
cb2c8f694d [clang] Use value instead of getValue (NFC) 2022-07-13 23:39:33 -07:00
Kazu Hirata
97afce08cb [clang] Don't use Optional::hasValue (NFC)
This patch replaces Optional::hasValue with the implicit cast to bool
in conditionals only.
2022-06-25 22:26:24 -07:00
Kazu Hirata
3b7c3a654c Revert "Don't use Optional::hasValue (NFC)"
This reverts commit aa8feeefd3ac6c78ee8f67bf033976fc7d68bc6d.
2022-06-25 11:56:50 -07:00
Kazu Hirata
aa8feeefd3 Don't use Optional::hasValue (NFC) 2022-06-25 11:55:57 -07:00
Stanislav Gatev
87c32be023 [clang][dataflow] Include terminator statements in buildStmtToBasicBlockMap
This will be necessary later when we add support for evaluating logic
expressions such as && and ||.

This is part of the implementation of the dataflow analysis framework.
See "[RFC] A dataflow analysis framework for Clang AST" on cfe-dev.

Reviewed-by: xazax.hun

Differential Revision: https://reviews.llvm.org/D119447
2022-02-11 11:15:29 +00:00
Stanislav Gatev
963f40051a [clang][dataflow] Add transfer functions for initializers
This is part of the implementation of the dataflow analysis framework.
See "[RFC] A dataflow analysis framework for Clang AST" on cfe-dev.

Reviewed-by: ymandel, xazax.hun

Differential Revision: https://reviews.llvm.org/D117123
2022-01-12 21:51:39 +00:00
Stanislav Gatev
b5c5d8912e [clang][dataflow] Add support for noreturn destructor calls
This is part of the implementation of the dataflow analysis framework.
See "[RFC] A dataflow analysis framework for Clang AST" on cfe-dev.

Reviewed By: xazax.hun, gribozavr2

Differential Revision: https://reviews.llvm.org/D116022
2021-12-28 07:04:39 +00:00