Commit Graph

11 Commits

Author SHA1 Message Date
Artem Dergachev 6603052235 [CFG] [analyzer] Recall that we only skip NoOp casts in construction contexts.
For now. We should also add support for ConstructorConversion casts as presented
in the attached test case, but this requires more changes because AST around
them seems different.

The check was originally present but was accidentally lost during r326021.

Differential Revision: https://reviews.llvm.org/D43840

llvm-svn: 326402
2018-03-01 01:09:24 +00:00
Artem Dergachev a6d91d5b30 [CFG] Provide construction contexts for temporaries in conditional operators.
When a lifetime-extended temporary is on a branch of a conditional operator,
materialization of such temporary occurs after the condition is resolved.

This change allows us to understand, by including the MaterializeTemporaryExpr
in the construction context, the target for temporary materialization in such
cases.

Differential Revision: https://reviews.llvm.org/D43483

llvm-svn: 326019
2018-02-24 03:10:15 +00:00
Artem Dergachev 8cc55e9f16 [CFG] Provide construction contexts for temporaries bound to const references.
In order to bind a temporary to a const lvalue reference, a no-op cast is added
to make the temporary itself const, and only then the reference is taken
(materialized). Skip the no-op cast when looking for the construction context.

Differential Revision: https://reviews.llvm.org/D43481

llvm-svn: 326016
2018-02-24 02:07:50 +00:00
Artem Dergachev ceb7d91a48 [CFG] Provide construction contexts for functional cast-like constructors.
When a constructor of a temporary with a single argument is treated
as a functional cast expression, skip the functional cast expression
and provide the correct construction context for the temporary.

Differential Revision: https://reviews.llvm.org/D43480

llvm-svn: 326015
2018-02-24 02:05:11 +00:00
Artem Dergachev f43ac4c9ac [CFG] Provide construction contexts for lifetime-extended temporaries.
When constructing a temporary that is going to be lifetime-extended through a
MaterializeTemporaryExpr later, CFG elements for the respective constructor
can now be queried to obtain the reference to that MaterializeTemporaryExpr
and therefore gain information about lifetime extension.

This may produce multi-layered construction contexts when information about
both temporary destruction and lifetime extension is available.

Differential Revision: https://reviews.llvm.org/D43477

llvm-svn: 326014
2018-02-24 02:00:30 +00:00
Artem Dergachev 1f68d9d39e [CFG] Provide construction contexts for temproary objects.
Constructors of C++ temporary objects that have destructors now can be queried
to discover that they're indeed constructing temporary objects.

The respective CXXBindTemporaryExpr, which is also repsonsible for destroying
the temporary at the end of full-expression, is now available at the
construction site in the CFG. This is all the context we need to provide for
temporary objects that are not lifetime extended. For lifetime-extended
temporaries, more context is necessary.

Differential Revision: https://reviews.llvm.org/D43056

llvm-svn: 325210
2018-02-15 03:13:36 +00:00
Artem Dergachev 9ac2e11385 [CFG] Provide construction contexts for return value constructors.
When the current function returns a C++ object by value, CFG elements for
constructors that construct the return values can now be queried to discover
that they're indeed participating in construction of the respective return value
at the respective return statement.

Differential Revision: https://reviews.llvm.org/D42875

llvm-svn: 324952
2018-02-12 22:36:36 +00:00
Artem Dergachev 08225bbed4 [CFG] Provide construction contexts when constructors have cleanups.
Now that we make it possible to query the CFG constructor element to find
information about the construction site, possible cleanup work represented by
ExprWithCleanups should not prevent us from providing this information.

This allows us to have a correct construction context for variables initialized
"by value" via elidable copy-constructors, such as 'i' in

  iterator i = vector.begin();

Differential Revision: https://reviews.llvm.org/D42719

llvm-svn: 324798
2018-02-10 02:46:14 +00:00
Artem Dergachev 5a281bba40 [CFG] Add construction context for constructor initializers.
CFG elements for constructors of fields and base classes that are being
initialized before the body of the whole-class constructor starts can now be
queried to discover that they're indeed participating in initialization of their
respective fields or bases before the whole-class constructor kicks in.

CFG construction contexts are now capable of representing CXXCtorInitializer
triggers, which aren't considered to be statements in the Clang AST.

Differential Revision: https://reviews.llvm.org/D42700

llvm-svn: 324796
2018-02-10 02:18:04 +00:00
Artem Dergachev 5fc10337a2 [CFG] Add construction context for simple variable declarations.
Constructors of simple variables now can be queried to discover that they're
constructing into simple variables.

Differential Revision: https://reviews.llvm.org/D42699

llvm-svn: 324794
2018-02-10 01:55:23 +00:00
Artem Dergachev 41ffb30716 [CFG] Add extra context to C++ constructor statement elements.
This patch adds a new CFGStmt sub-class, CFGConstructor, which replaces
the regular CFGStmt with CXXConstructExpr in it whenever the CFG has additional
information to provide regarding what sort of object is being constructed.

It is useful for figuring out what memory is initialized in client of the
CFG such as the Static Analyzer, which do not operate by recursive AST
traversal, but instead rely on the CFG to provide all the information when they
need it. Otherwise, the statement that triggers the construction and defines
what memory is being initialized would normally occur after the
construct-expression, and the client would need to peek to the next CFG element
or use statement parent map to understand the necessary facts about
the construct-expression.

As a proof of concept, CFGConstructors are added for new-expressions
and the respective test cases are provided to demonstrate how it works.

For now, the only additional data contained in the CFGConstructor element is
the "trigger statement", such as new-expression, which is the parent of the
constructor. It will be significantly expanded in later commits. The additional
data is organized as an auxiliary structure - the "construction context",
which is allocated separately from the CFGElement.

Differential Revision: https://reviews.llvm.org/D42672

llvm-svn: 324668
2018-02-08 22:58:15 +00:00