[cfe-dev] operator* sema bug

[Steve Naroff]

Commit 45148 fixes the bug below.

Thanks for the report (Oliver),

snaroff

On Dec 15, 2007, at 11:30 AM, Steve Naroff wrote:

> I have a look later today...
>
> Glad to hear you are feeling better!
>
> snaroff
>
> On Dec 15, 2007, at 9:38 AM, Chris Lattner wrote:
>
>>
>> On Dec 14, 2007, at 11:57 PM, Oliver Hunt wrote:
>>
>>> So i'm looking at this failure:
>>> typedef struct { char name[100]; } entry;
>>> char f1(entry *e) { return *e->name; }
>>>
>>>
>>> The problem appears to be CodeGenFunction::EmitScalarExpr being  
>>> called on e->name as it believes
>>> e->name is an array type rather than a scalar, so we assert.
>>>
>>> I'm not sure what the appropriate correction should be -- should i  
>>> fix
>>> CodeGenFunction::EmitLoadOfLValue
>>> So that it can handle an array type -- emitting an array type as  
>>> an lvalue should just be to emit a getElementPtr(array, 0)
>>>
>>> Or alternatively have a step during merge to convert *array to  
>>> array[0]
>>
>> Hi Oliver,
>>
>> Sorry for the delay, I've been majorly sick since thursday night.   
>> I don't think this is a codegen bug, I think it's a sema bug:
>>
>> $ clang t3.c -ast-dump
>> typedef char *__builtin_va_list;
>> typedef struct <anonymous> entry;
>>
>> char f1(entry *e)
>> (CompoundStmt 0x8061e0 <t3.c:2:19, col:38>
>>   (ReturnStmt 0x8061d0 <col:21, col:32>
>>     (UnaryOperator 0x8061b0 <col:28, col:32> 'char' prefix '*'
>>       (MemberExpr 0x806180 <col:29, col:32> 'char [100]' ->name  
>> 0x805f00
>>         (DeclRefExpr 0x806160 <col:29> 'entry *' ParmVar='e'  
>> 0x806120)))))
>>
>> Sema is properly inferring that the * has type char, but it isn't  
>> inserting an implicit cast.  I'd expect to see something like this:
>>
>> clang t3.c -ast-dump
>> typedef char *__builtin_va_list;
>> typedef struct <anonymous> entry;
>>
>> char f1(entry *e)
>> (CompoundStmt 0x8061e0 <t3.c:2:19, col:38>
>>   (ReturnStmt 0x8061d0 <col:21, col:32>
>>     (UnaryOperator 0x8061b0 <col:28, col:32> 'char' prefix '*'
>>       (ImplicitCast char*
>>         (MemberExpr 0x806180 <col:29, col:32> 'char [100]' ->name  
>> 0x805f00
>>           (DeclRefExpr 0x806160 <col:29> 'entry *' ParmVar='e'  
>> 0x806120))))))
>>
>> Maybe Steve can take a look if he has a chance,
>>
>> -Chris
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>

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