[lldb-dev] Symtab for PECOFF

[Aleksandr Urakov via lldb-dev]

Thanks!

I've almost done this, I'll test it more carefully on the next week and
will create a review.

On Fri, Aug 31, 2018 at 4:54 PM Zachary Turner <zturner at google.com> wrote:

> That would be my thought, yea
> On Fri, Aug 31, 2018 at 1:21 AM Aleksandr Urakov <
> aleksandr.urakov at jetbrains.com> wrote:
>
>> Thanks for the reply!
>>
>> Yes, the function search is implemented in the way similar to what you
>> have described (and even the search in a symbol file is done before the
>> search in a symtab). But for Module::FindSymbolsWithNameAndType function I
>> can't find any relevant function in the SymbolFile. Do you mean that we
>> need to extend the SymbolFile interface with such a function (which will
>> search all public symbols by the name and the type), and then implement it
>> in derived classes?
>>
>> On Thu, Aug 30, 2018 at 6:03 PM Zachary Turner <zturner at google.com>
>> wrote:
>>
>>> It seems reasonable to me to say that if the symbol is not found in the
>>> executables symtab, it will fall back to searching in the symbol file..
>>> this logic doesn’t even need to be specific to PDB
>>> On Thu, Aug 30, 2018 at 7:00 AM Aleksandr Urakov via lldb-dev <
>>> lldb-dev at lists.llvm.org> wrote:
>>>
>>>> Hello!
>>>>
>>>> I'm working on an expressions evaluation on Windows, and currently I'm
>>>> trying to make a JIT evaluation working.
>>>>
>>>> When I'm trying to evaluate the next expression:
>>>>
>>>> print S::x
>>>>
>>>>
>>>> on the next code:
>>>>
>>>> struct S {
>>>>   static int x;
>>>>   void foo() { }
>>>> };
>>>> int S::x = 5;
>>>>
>>>> int main() {
>>>>   S().foo(); // here
>>>>   return 0;
>>>> }
>>>>
>>>>
>>>> the evaluation requires JIT (but printing of global variables requires
>>>> not, and I can't figure out what is the key difference between a class
>>>> static variable and a global variable in the case?).
>>>>
>>>> During symbols resolving IRExecutionUnit::FindInSymbols is used, and
>>>> it searches a symbol among functions (which is not our case), and then
>>>> calls Module::FindSymbolsWithNameAndType for each module in the list.
>>>> This function looks symbols up in a Symtab, which is retrieved through
>>>> a SymbolVendor, and it retrieves one from an ObjectFile. ELF files
>>>> contain symbols for such a variables in their symbol tables, but the
>>>> problem is that PE files usually contain info about exported (and imported)
>>>> symbols only, so the lookup in Symtab fails.
>>>>
>>>> I think that we need somehow to retrieve a symbols info from a symbol
>>>> file. I thought that we can emit a Symtab from a SymbolFile just like
>>>> from an ObjectFile (and for now implement it for SymbolFilePDB only),
>>>> but I'm not sure if this solution is good. How can we solve the problem
>>>> else?
>>>>
>>>> --
>>>> Aleksandr Urakov
>>>> Software Developer
>>>> JetBrains
>>>> http://www.jetbrains.com
>>>> The Drive to Develop
>>>> _______________________________________________
>>>> lldb-dev mailing list
>>>> lldb-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
>>>>
>>>
>>
>> --
>> Aleksandr Urakov
>> Software Developer
>> JetBrains
>> http://www.jetbrains.com
>> The Drive to Develop
>>
>

-- 
Aleksandr Urakov
Software Developer
JetBrains
http://www.jetbrains.com
The Drive to Develop
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