This PR adds the support for determining the origin of a pointer in a
conditional operator.
Because such an expression can have two distinct origins each of which
needs to be visited, this PR refactors tryToFindPtrOrigin to take a
callback instead of returning a pair.
The callback is called for the second operand and the third operand of
the conditioanl operator (i.e. E2 and E3 in E1 ? E2 : E3).
Also treat nullptr and integer literal as safe pointer origins in the
local variable checker.
Skip the analysis of Ref, RefPtr, and their variant classes in
UncountedCallArgsChecker since these classes are "trusted" to not do
anything dangerous.
This PR introduces the concept of a "trivial function" which applies to
a function that only calls other trivial functions and contain literals
and expressions that don't result in heap mutations (specifically it
does not call deref). This is implemented using ConstStmtVisitor and
checking each statement and expression's trivialness.
This PR also introduces the concept of a "ingleton function", which is a
static member function or a free standing function which ends with the
suffix "singleton". Such a function's return value is understood to be
safe to call any function with.
There are currently a few checkers that don't fill in the bug report's
"decl-with-issue" field (typically a function in which the bug is
found).
The new attribute `[[clang::suppress]]` uses decl-with-issue to reduce
the size of the suppression source range map so that it didn't need to
do that for the entire translation unit.
I'm already seeing a few problems with this approach so I'll probably
redesign it in some point as it looks like a premature optimization. Not
only checkers shouldn't be required to pass decl-with-issue (consider
clang-tidy checkers that never had such notion), but also it's not
necessarily uniquely determined (consider leak suppressions at
allocation site).
For now I'm adding a simple stop-gap solution that falls back to
building the suppression map for the entire TU whenever decl-with-issue
isn't specified. Which won't happen in the default setup because luckily
all default checkers do provide decl-with-issue.
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Co-authored-by: Balazs Benics <benicsbalazs@gmail.com>
