do not set values if there is no expression

[firewave]

No description provided.

[firewave]

All tests still pass with the early returns added.

Example output:

TestLeakAutoVar::doublefree9
ExprIdToken - no tok
setValue - no expr - 0@1
setValue - no expr - 0@1
ExprIdToken - no tok
setValue - no expr - 1@2
setValue - no expr - 1@2
setValue - no expr - 1
setValue - no expr - 0

Looks like this is related to unnamed parameters.

@pfultz2 please have a look.

[firewave]

Happens with unnamed parameters when a function body exists:

void cb(int) {}

void func()
{
    cb(0);
}

ExprIdToken - no tok
setValue - no expr - 0@1
ExprIdToken - no tok
solveExprValue - no expr
setValue - no expr - 0@1
ExprIdToken - no tok
solveExprValue - no expr


##file scratch_3.cpp
1: void cb ( int ) { }
2:
3: void func ( )
4: {
5: cb (@exprUNIQUE 0 ) ;
6: }



##Value flow
File scratch_3.cpp
Line 5
  0 always 0

Naming the parameter fixes it:

##file scratch_3.cpp
1: void cb ( int i@var1 ) { }
2:
3: void func ( )
4: {
5: cb (@exprUNIQUE 0 ) ;
6: }



##Value flow
File scratch_3.cpp
Line 5
  0 always 0

[firewave]

The MultiValueFlowAnalyzer happens in TestAutoVariables::testinvaliddealloc (among others). I assume that should not get such data so it possibly needs to be addressed earlier in the code.

[firewave]

This occurs in e.g. TestAutoVariables::testinvaliddealloc.

The Variable has no mNameToken and points to void* which appears to be the injected parameter for free(). The errorPath in the values seems to support this:

Address of variable taken here.

Calling function 'free', 1st argument '&c2' value is lifetime=c2

Not sure if something with the injecting is lacking data. But I do not think this needs to be solved in the scope of this PR.

@pfultz2 Any thoughts?

[danmar]

spontanously this sounds good to me.
what is the motivation?
is there speedup or change of results or simpler code?

[firewave]

spontanously this sounds good to me. what is the motivation? is there speedup or change of results or simpler code?

I cannot remember how I came across this but I assume it was in the context of some of the other drafts PRs where I try to get rid of unnecessary calls.

Depending on the code this might have performance implications as less values are being generated.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[firewave]

I tested it with #7800 and there were no differences in the output.