14 Commits

Author SHA1 Message Date
Yitzhak Mandelbaum
73c98831f6 [clang][dataflow] Fix missed fields in field set construction.
When building the set of referenced fields for the `DataflowAnalysisContext`,
include fields referenced only in default member initializers. These
initializers are visited in the CFGs of constructors and so the fields must be
included when analysing constructor bodies.

Differential Revision: https://reviews.llvm.org/D144987
2023-02-28 18:56:54 +00:00
Yitzhak Mandelbaum
3ce03c42db [clang][dataflow] Fix 2 bugs in MemberExpr interpretation.
There were two (small) bugs causing crashes in the analysis.  This patch fixes both of them.

1. An enum value was accessed as a class member. Now, the engine gracefully
ignores such member expressions.

2. Field access in `MemberExpr` of struct/class-typed global variables. Analysis
didn't interpret fields of global vars, because the vars were initialized before
the fields were added to the "allowlist". Now, the allowlist is set _before_
init of globals.

Differential Revision: https://reviews.llvm.org/D141384
2023-01-10 15:48:00 +00:00
Yitzhak Mandelbaum
01ccf7b3ce Revert "Revert "[clang][dataflow] Only model struct fields that are used in the function being analyzed.""
This reverts commit 2b1a517a92bfdfa3b692a660e19a2bb22513a567. It's a fix forward
with two memory errors fixed, one of which was the cause of the build breakage
in the buildbots.

Original message:

Previously, the model for structs modeled all fields in a struct when
`createValue` was called for that type. This patch adds a prepass on the
function under analysis to discover the fields referenced in the scope and then
limits modeling to only those fields. This reduces wasted memory usage
(modeling unused fields) which can be important for programs that use large
structs.

Note: This patch obviates the need for https://reviews.llvm.org/D123032.
2023-01-09 19:32:10 +00:00
Yitzhak Mandelbaum
2b1a517a92 Revert "[clang][dataflow] Only model struct fields that are used in the function being analyzed."
This reverts commit 5e8f597c2fedc740b71f07dfdb1ef3c2d348b193. It caused msan and ubsan breakages.
2023-01-06 01:07:28 +00:00
Yitzhak Mandelbaum
5e8f597c2f [clang][dataflow] Only model struct fields that are used in the function being analyzed.
Previously, the model for structs modeled all fields in a struct when
`createValue` was called for that type. This patch adds a prepass on the
function under analysis to discover the fields referenced in the scope and then
limits modeling to only those fields.  This reduces wasted memory usage
(modeling unused fields) which can be important for programss that use large
structs.

Note: This patch obviates the need for https://reviews.llvm.org/D123032.

Differential Revision: https://reviews.llvm.org/D140694
2023-01-05 21:46:39 +00:00
Yitzhak Mandelbaum
f3700bdb7f [clang][dataflow] Account for global variables in constructor initializers.
Previously, the analysis modeled global variables appearing in the _body_ of
any function (including constructors). But, that misses those appearing in
constructor _initializers_. This patch adds the initializers to the set of
expressions used to determine which globals to model.

Differential Revision: https://reviews.llvm.org/D140501
2022-12-22 14:20:50 +00:00
Sam Estep
32dcb759c3 [clang][dataflow] Move NoopAnalysis from unittests to include
This patch moves `Analysis/FlowSensitive/NoopAnalysis.h` from `clang/unittests/` to `clang/include/clang/`, so that we can use it for doing context-sensitive analysis.

Reviewed By: ymandel, gribozavr2, sgatev

Differential Revision: https://reviews.llvm.org/D130304
2022-07-22 14:11:32 +00:00
Wei Yi Tee
00e9d53453 [clang][dataflow] Move logic for creating implication and iff expressions into DataflowAnalysisContext from DataflowEnvironment.
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
2022-06-24 23:16:44 +02:00
Stanislav Gatev
3dd7877b27 Revert "[clang][dataflow] Move dataflow testing support out of unittests"
This reverts commit 26bbde2612b2042c3a8a31aed7f45e065c3dd413.
2022-03-09 15:38:51 +00:00
Stanislav Gatev
26bbde2612 [clang][dataflow] Move dataflow testing support out of unittests
This enables tests out of clang/unittests/Analysis/FlowSensitive to
use the testing support utilities.

Reviewed-by: ymandel, gribozavr2

Differential Revision: https://reviews.llvm.org/D121285
2022-03-09 15:31:02 +00:00
Stanislav Gatev
e0cc28dfdc Revert "[clang][dataflow] Add analysis that detects unsafe accesses to optionals"
This reverts commit ce205cffdfa0f16ce9441ba46fa43e23cecf8be7.
2022-03-09 09:51:03 +00:00
Stanislav Gatev
ce205cffdf [clang][dataflow] Add analysis that detects unsafe accesses to optionals
Adds a dataflow analysis that detects unsafe accesses to values of type
`std::optional`, `absl::optional`, or `base::Optional`.

Reviewed-by: ymandel, xazax.hun

Differential Revision: https://reviews.llvm.org/D121197
2022-03-09 09:42:51 +00:00
Yitzhak Mandelbaum
18c84e2d32 [clang][dataflow] Fix nullptr dereferencing error.
When pre-initializing fields in the environment, the code assumed that all
fields of a struct would be initialized. However, given limits on value
construction, that assumption is incorrect. This patch changes the code to drop
that assumption and thereby avoid dereferencing a nullptr.

Differential Revision: https://reviews.llvm.org/D121158
2022-03-08 03:01:31 +00:00
Stanislav Gatev
ae60884dfe [clang][dataflow] Add flow condition constraints to Environment
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/D120711
2022-03-02 08:57:27 +00:00