Good catch, the fix is reasonable to me. However, I'm no longer wok on the analyzer now, maybe you can add @NoQ Or some other active reviewers to review the code.

In D55388#1322601, @xazax.hun wrote:

Hm. I wonder if it would also make sense to model e.g. the get method to return nullptr for moved from smart ptrs. This could help null dereference checker and also aid false path prunning.

Please add more context using the -U option, like git diff -U99999 ....

In D54878#1307726, @ilya-biryukov wrote:

But given that isa<> are still better than dyn_cast<>, this change might still be worth landing.

We can land this change this time or do the cleaning job in other patches in the future, it's all up to you guys, the active clangd contributors.

Use more concise form.

Thank you for doing the cleaning that no one else is interested in! Comments is inline below.

The "moved-from" terminology we adopt here still feels a bit weird to me, but i don't have a better suggestion, so i just removed the single-quotes so that to at least feel proud about what we have.

I am personally fine with this terminology, this checker corresponds to the cert rule EXP63-CPP. Do not rely on the value of a moved-from object, and moved from is also used in many places in CppCoreGuidelines.

I'm totally fine with this patch personally. However I am not familiar with this part, so can't give substantial help :).

Sorry for the long delay for this patch! The implementation is fine for me. However, I'm the newbie on clang diagnostics and have no further insight into this checker. @aaron.ballman may have more valuable insights into this checker.

In addition, clang/lib/StaticAnalyzer/README.txt and other related docs in clang/lib/docs/analyzer are also out of date.

In D52949#1268640, @xbolva00 wrote:

Second thought, I don't think we should recommend std::size here (maybe it should be okay for clang static analyzers)

uint32_t data[] = {10, 20, 30, 40};
len = sizeof(data)/sizeof(*data); // "warn" on valid code to recommend std::size? I dont agree with such behaviour.

In D53024#1258976, @Szelethus wrote:

Also, a lot of items on this list is outdated, but I joined the project relatively recently, so I'm not sure what's the state on all of them.

Greate idea! If we can enrich this list, it will not only help the reviewer, but also help beginners, like me, avoid some pitfalls when developing a new checker.

Thank you for digging in to delete that meaningless constructor, NoQ! And sorry for my technology debt : ).

In D48027#1209844, @NoQ wrote:

So i believe that one of the important remaining problems with CallDescription is to teach it to discriminate between global functions and methods. We can do it in a number of ways:

1. Make a special sub-class for CallDescription depending on the sort of the function (too verbose),
2. Tag all items in the list as "record" vs. "namespace" (too many tags),
3. Dunno, tons of other boring and verbose approaches,
4. Change our PreCall/PostCall callbacks to callback templates that let allow the user subscribe to specific sub-classes of CallEvent similarly to how he can subscribe to different kinds of statements in PreStmt<Class>/PostStmt<Class>, and then the user doesn't need to write any code to check it dynamically.

In D48027#1207645, @xazax.hun wrote:

Sorry for the delay, I think this is OK to commit.
As a possible improvement, I can imagine making it slightly stricter, e.g. you could only skip QualifiedNames for inline namespaces and the beginning. Maybe add support for staring with "" or :: to even disable skipping namespaces at the beginning?
But these are just nice to have features, I am perfectly ok with not having them or doing it in a followup patch.

@xazax.hun What do you think?

In D48027#1201248, @xazax.hun wrote:

Generally looks good, I only wonder if this works well with inline namespaces. Could you test? Probably it will.

• rebase
• Since we have enhanced the ability of CallDescription, remove the helper method isCalledOnStringObject().

kindly ping!

@xazax.hun Thanks for your tips! After some investigation, MatchFinder::match just traverse one ASTNode, that means match(namedDecl(HasNameMatcher())) and match(namedDecl(matchesName())) both not traverse children. So there are three ways to match the specified AST node.

Thanks for your review, NoQ!

kindly ping!

Sorry for the long long delay, I was on the Dragon Boat Festival a few days ago.

• Use hasName matcher to match the qualified name.

In D48027#1128301, @xazax.hun wrote:

Having C++ support would be awesome!
Thanks for working on this!

While I do agree matching is not trivial with qualified names, this problem is already solved with AST matchers.

I wonder if using matchers or reusing the HasNameMatcher class would make this easier. That code path is already well tested and optimized.

Remove useless header files for testing.

The implementation is not complicated, the difficulty is that there is no good way to get the qualified name without template arguments. For std::basic_string::c_str(), its qualified name may be std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::c_str, it is almost impossible for users to provide such a name. So one possible implementation is to use std, basic_string and c_str to match in the std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::c_str sequentially.

In D47973#1127309, @vsk wrote:

Thanks for the patch. The StringRef change itself looks fine, but please make sure to update the callsites in-tree (e.g in llvm, clang, lldb etc).

LGTM, @NoQ May have further feedback. Thanks!

I didn't test the code, but the code seems correct. Thanks!

In D47406#1120360, @zturner wrote:

rsplit(char) already exists. That said, another way to reuse code would be
to have rsplit(char) call the StringRef version

In D47406#1120355, @vsk wrote:

Hi @MTC, thanks for the patch.

With this patch, the logic for split would be duplicated 3 times now in StringRef.h. I think it'd be nice to reuse some code by moving the core logic into a private method of StringRef, say, splitAtIndex(size_t). Then, each (r)split(char | StringRef) can use the common helper.

Relatedly, an rsplit(char) overload seems to be missing here.

This update consists of two parts

• Make rsplit(char) reuse rsplit(StringRef).
• Make split(char) reuse split(StringRef).

ping.

• According to NoQ's suggestion, use assumeZero() instead of isZeroConstant() to determine whether the value is 0.
• Add test memset26_upper_UCHAR_MAX() and memset27_symbol()
• Since memset( void *dest, int ch, size_t count) will converts the value ch to unsigned char, we call evalCast() accordingly.

ping.

• Since there is no perfect way to handle the default binding of non-zero character, remove the default binding of non-zero character. Use bindDefaulrZero() instead of overwriteRegion() to bind the zero character.
• Reuse assume() instead of isZeroConstant() to determine whether it is zero character. The purpose of this is to be able to set the string length when dealing with non-zero symbol character.

In D44934#1088771, @NoQ wrote:

Hmm, ok, it seems that i've just changed the API in D46368, and i should have thought about this use case. Well, at least i have some background understanding of these problems now. Sorry for not keeping eye on this problem.

In D44934#1051002, @NoQ wrote:

Why do you need separate code for null and non-null character? The function's semantics doesn't seem to care.

I guess i can answer myself here:

int32_t x;
memset(&x, 1, sizeof(int32_t));
clang_analyzer_eval(x == 0x1010101); // should be TRUE

I really doubt that we support this case.

So, yeah, zero character is indeed special.

Thank you, Artem! I did not consider this common situation. This patch does not really support this situation, in this patch the value of x will be 1, it's not correct!

• fix typos
• code refactoring, add auxiliary method memsetAux()
• according to a.sidorin's suggestions, remove the useless state splitting.
• make StoreManager::overwriteRegion() pure virtual

Sorry for the long delay, I have just finished my holiday.

ping^2

Since BugReport::addVisitor() has checks for the null Visitor, remove the checks before BugReport->addVisitor().

In D45682#1074407, @george.karpenkov wrote:

I'm new to the taint visitor, but I am quite confused by your change description.

and many checkers rely on it

How can other checkers rely on it if it's private to the taint checker?

Thanks for your review, george! TaintBugVisitor is an utility to add extra information to illustrate where the taint information originated from. There are several checkers use taint information, e.g. ArrayBoundCheckerV2.cpp, in some cases it will report a warning, like warning: Out of bound memory access (index is tainted). If TaintBugVisitor moves to BugReporterVisitors.h, ArrayBoundCheckerV2 can add extra notes like Taint originated here to the report by adding TaintBugVisitor.

Test files for initialization missing? : )

In D45532#1069683, @whisperity wrote:

There is something that came up in my mind:

Consider a construct like this:

class A
{
  A()
  {
    memset(X, 0, 10 * sizeof(int));
  }

  int X[10];
};

I think it's worthy for a test case if this X is considered unitialised at the end of the constructor or not. (And if not, a ticket, or a fix for SA in a subpatch.)

In D45491#1067852, @NoQ wrote:

Yeah, i think this makes sense, thanks! It feels a bit weird that we have to add it as an exception - i wonder if there are other exceptions that we need to make. Widening over the stack memory space should be a whitelist, not a blacklist, because we can easily enumerate all stack variables and see which of them can be modified at all from the loop. But until we have that, this looks like a reasonable workaround.

• Move the CXXThisRegion's check to LoopWidening.cpp
• Use isa<CXXThisRegion>(R) instead of CXXThisRegion::classof(R).

In D45491#1063364, @george.karpenkov wrote:

@MTC what happens for

this.j = 0;
for (int i=0; i<100; i++)
   this.j++;

?

Kindly ping!

Thank you for your reminding, I overlooked this point. However for non-concrete character, the symbol value, if we just invalidate the region, the constraint information of the non-concrete character will be lost. Do we need to consider this?

Fix typo, unsinged -> unsigned

According to @NoQ's suggestion, remove the duplicated code.

Thanks for your review, NoQ!