[cfe-dev] how does clang tackle DeclContext, like ForContext

[Nikola Smiljanic]

Adding back cfe-dev

If you're tying to introduce a new variable I suggest you look at what
happens with 'i' in 'for (int i;;)'. I don't think your code is adding the
VarDecl to the AST, you're building the node but how does it connect to
existing nodes? You probably don't want to do all this work manually
anyway, I'm not sure if ActOnVariableDeclarator is the right function but
it might do most of the work for you. I'm not sure how IdentifierResolver,
IdentifierTable and other machinery is supposed to be updated by one of
Sema functions likely does it.

On Tue, May 12, 2015 at 1:01 PM, Eric Lu <eirc.lew at gmail.com> wrote:

> Then, how to create the DeclContext chain.
> If I want to create a new variable declaration in for loop in the AST, how
> to add the variable into the ForContext?
>
> Now, I do like below, but it is said the variable not declared.
>
> StmtResult Sema::ActOnForInitDeclStmt(IdentifierInfo &II, SourceLocation
> StartLoc, SourceLocation EndLoc)
> const char *PrevSpec; // ? Do what?
>   unsigned DiagID;
>   AttributeFactory Attrs;
>   DeclSpec DS(Attrs );
>   DS.SetTypeSpecType(DeclSpec::TST_int, StartLoc, PrevSpec, DiagID,
>       getPrintingPolicy() );
>   Declarator D(DS, Declarator::ForContext);
>   D.SetIdentifier(&II, StartLoc );
>
>   DeclContext *DC = CurContext; // TBD.
>   Scope *Scp = getScopeForContext(DC);
>   TypeSourceInfo *TInfo = GetTypeForDeclarator(D, Scp);
>   QualType R = TInfo->getType();
>   DeclSpec::SCS SCSpec = D.getDeclSpec().getStorageClassSpec();
>
>   VarDecl::StorageClass SC = SC_None;
>   VarDecl *VDecl = VarDecl::Create(Context, DC, D.getLocStart(),
> D.getIdentifierLoc(),&II, R, TInfo, SC);
>   Decl *Var = VDecl;
>
>   SmallVector<Decl*, 8> Decls;
>   Decls.push_back(Var);
>   DeclGroupPtrTy DGP = BuildDeclaratorGroup( Decls );
>   DeclGroupRef DGR = DGP.get();
>   DeclStmt *VDS = new (Context) DeclStmt(DGR, StartLoc,
>      StartLoc);
>
>
>
>
>
>
>
> On Sat, May 9, 2015 at 10:23 AM, Nikola Smiljanic <popizdeh at gmail.com>
> wrote:
>
>> By performing a name lookup into appropriate Scope. Scopes are linked in
>> a chain and name lookup traverses them starting from the inner one.
>>
>> On Sat, May 9, 2015 at 3:09 AM, Eric Lu <eirc.lew at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> In a C for loop like:
>>> int a[10];
>>> for(int i = 0; i < 10; i++){
>>>    a[i] = i + 1;
>>> }
>>>
>>> The variable "i" is declared in the ForContext in ParseForStatement(),
>>> and then when parse body, I.E., the expression "a[i]" later, how does it
>>> know that "i" is declared?
>>>
>>> In other words, how does the ForContext affect the later parsing of
>>> variable "i" ?
>>>
>>> --
>>> Best Regards!
>>> Eric Lew
>>>
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>>
>>>
>>
>
>
> --
> Best Regards!
> Eric Lew
>
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