[cfe-dev] Matching function argument that may not be valid

[Manuel Klimek]

On Thu, Apr 23, 2015 at 9:41 PM Daniel Dilts <diltsman at gmail.com> wrote:

> I want to insert the enum constants from the values that are in the code.
> One driving reason behind this is that there isn't really any single group
> that owns the enum.  One group could write it, but then nobody else would
> be permitted to modify it.  A different group could write it, but then they
> would have to generate some matching tables by hand.  Neither option is
> really acceptable.
>
> The ideal is to write the enum value and pull it out of the code and
> generate the enum and associated tables.
>

The way one usually does that is by not using an enum, but by using an
integer type and "value ranges".
I don't think trying to parse incorrect code is the right approach. If you
really want a code-gen approach, you'd need a list of enum values per user
that you then just hand to the codgen.
If you want to dynamically generate values, I'd use a dynamic language :)


>
> On Thu, Apr 23, 2015 at 11:13 AM, Manuel Klimek <klimek at google.com> wrote:
>
>>
>>
>> On Thu, Apr 23, 2015 at 7:43 PM Daniel Dilts <diltsman at gmail.com> wrote:
>>
>>> Yeah, I suspected as much.  Is there any real option for finding this
>>> location?  Would I have to do it where it is building the AST?
>>>
>>
>> Nope. For parsing incorrect code you need to write your own "parser". Why
>> do you want to parse incorrect code though?
>>
>>
>>>
>>> On Thu, Apr 23, 2015 at 10:25 AM, Manuel Klimek <klimek at google.com>
>>> wrote:
>>>
>>>> Ok, this only works on valid code. If you have errors, all bets are off.
>>>>
>>>> On Thu, Apr 23, 2015 at 7:23 PM Daniel Dilts <diltsman at gmail.com>
>>>> wrote:
>>>>
>>>>>
>>>>>
>>>>> On Fri, Apr 17, 2015 at 5:19 PM, Manuel Klimek <klimek at google.com>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Apr 16, 2015 at 5:45 PM Daniel Dilts <diltsman at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> I am attempting to write a tool that will generate a table from
>>>>>>> tokens pulled from source code.
>>>>>>>
>>>>>>> I have a static template function in a template class.  I want to
>>>>>>> find the first argument for all calls to the template function.
>>>>>>>
>>>>>>> The problem is that the token may or may not be defined, since they
>>>>>>> will be defined in a generated table.
>>>>>>>
>>>>>>> If I use dump-ast it appears that the function call is omitted from
>>>>>>> the AST, so I don't think that I can use AST matchers to find it.
>>>>>>>
>>>>>>
>>>>>> I somehow can't believe that - all calls are in the AST.
>>>>>>
>>>>>
>>>>>
>>>>> Here is my example, using "clang version 3.7.0 (trunk 235602)".  Note
>>>>> that the call to Func is not present in the AST.
>>>>>
>>>>> enum MyEnum
>>>>> {
>>>>> };
>>>>> void Func(MyEnum v);
>>>>> int main()
>>>>> {
>>>>>  Func(SomeEnumValue);
>>>>>  return 0;
>>>>> }
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> clang.exe -Xclang -ast-dump test.cpp
>>>>> test.cpp:7:7: error: use of undeclared identifier 'SomeEnumValue'
>>>>>         Func(SomeEnumValue);
>>>>>              ^
>>>>> TranslationUnitDecl 0x836140 <<invalid sloc>> <invalid sloc>
>>>>> |-CXXRecordDecl 0x836400 <<invalid sloc>> <invalid sloc> implicit
>>>>> class type_inf
>>>>> o
>>>>> | `-TypeVisibilityAttr 0x836470 <<invalid sloc>> Implicit Default
>>>>> |-TypedefDecl 0x8364b0 <<invalid sloc>> <invalid sloc> implicit size_t
>>>>> 'unsigned
>>>>>  int'
>>>>> |-TypedefDecl 0x836508 <<invalid sloc>> <invalid sloc> implicit
>>>>> __builtin_va_lis
>>>>> t 'char *'
>>>>> |-EnumDecl 0x836538 <test.cpp:1:1, line:3:1> line:1:6 referenced
>>>>> MyEnum 'int'
>>>>> |-FunctionDecl 0x836630 <line:4:1, col:19> col:6 Func 'void (enum
>>>>> MyEnum)'
>>>>> | `-ParmVarDecl 0x8365b8 <col:11, col:18> col:18 v 'enum MyEnum'
>>>>> `-FunctionDecl 0x836718 <line:5:1, line:9:1> line:5:5 main 'int (void)'
>>>>>   `-CompoundStmt 0x836880 <line:6:1, line:9:1>
>>>>>     `-ReturnStmt 0x836870 <line:8:2, col:9>
>>>>>       `-IntegerLiteral 0x836850 <col:9> 'int' 01 error generated.
>>>>>
>>>>>
>>>
>
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