[cfe-commits] r147306 - /cfe/trunk/lib/Analysis/CFG.cpp

[Ted Kremenek]

Interesting.  If the AST doesn't have enough information for the analyzer (and other clients) to do a good job here, then I think it would be reasonable to investigate pushing an AST-level change to fix the issue.

On Dec 29, 2011, at 4:03 AM, Xu Zhongxing wrote:

> I admit this is not a correct solution. If I set add CXXConstructExpr bit in the CFG::BuildOptions to false, there exist some cases CXXConstructExpr is not added as block-level expr, where it should.
> 
> Linearizing the CFG is great idea. I already enjoy it very much.
> 
> We need to provide more information to CXXConstructExpr: its destination object (a variable or a temporary object that should be conjured) and its kind (base,complete).
> 
> For the destination object, we could always conjure a temporary object and use LazyCompoundVal to bind the real object being constructed when we later see it.
> 
> 于 2011/12/29 13:59, Ted Kremenek 写道:
>> Hi Zhongxing,
>> 
>> I don't understand how this is actually fixing (1) or (2).  Can you explain?  We're moving to a place where we will likely linearize the entire CFG (this is already the case for the static analyzer), so it would be great to find a solution to (1) or (2) that doesn't depend on whether or not CXXConstructExpr is a block-level expression.
>> 
>> Thanks,
>> Ted
>> 
>> On Dec 27, 2011, at 8:38 PM, Zhongxing Xu wrote:
>> 
>>> Author: zhongxingxu
>>> Date: Tue Dec 27 22:38:46 2011
>>> New Revision: 147306
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=147306&view=rev
>>> Log:
>>> Enable the user to control whether CXXConstructExpr will be added as a
>>> block-level expr. Currently CXXConstructExpr is always added as a block-level
>>> expr. This caused two problems for the analyzer (and potentially for the
>>> CFG-based codegen).
>>> 1. We have no way to know whether a ctor call is base or complete.
>>> 2. We have no way to know the destination object being contructed.
>>> 
>>> Modified:
>>>   cfe/trunk/lib/Analysis/CFG.cpp
>>> 
>>> Modified: cfe/trunk/lib/Analysis/CFG.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CFG.cpp?rev=147306&r1=147305&r2=147306&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Analysis/CFG.cpp (original)
>>> +++ cfe/trunk/lib/Analysis/CFG.cpp Tue Dec 27 22:38:46 2011
>>> @@ -2768,7 +2768,7 @@
>>> CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
>>>                                            AddStmtChoice asc) {
>>>  autoCreateBlock();
>>> -  if (!C->isElidable())
>>> +  if (!C->isElidable()&&  asc.alwaysAdd(*this, C))
>>>    appendStmt(Block, C);
>>> 
>>>  return VisitChildren(C);
>>> 
>>> 
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