llvm dev - Jul 2015 - [LLVMdev] SymbolRef and getSize

Hi everyone,

I’m currently playing with the clang driver and I encounter a strange bug.

It occurs when I used the getSize function from the SymbolRef class.

On iOS, the number returned is not always correct (some function have the right
size).

Sadly,

This is my code (at the end of the main function into driver.cpp) :

####

ErrorOr<OwningBinary<Binary>> BinaryOrErr = createBinary(file);
if (std::error_code ec = BinaryOrErr.getError()) {
  return ec.value();
}

Binary &Binary = *BinaryOrErr.get().getBinary();
object::ObjectFile *objfile;

objfile = dyn_cast<ObjectFile>(&Binary);

for (const SymbolRef &Symbol : objfile->symbols()) {
uint64_t size;
  Symbol.getAddress(size);

}

####

During my previous search, I check machODump.cpp in order to see of the list all
the function.

They never use the getSize() but they use the address (getAddress()) of the next
function.

Does anyone have ever heard of a bug with this function or did I do something
wrong?

Greeting,

Johan Wehrli

> On 15.07.2015, at 17:52, Wehrli Johan <johan.wehrli at heig-vd.ch>
wrote:
> 
> 
> Hi everyone,
> 
> I’m currently playing with the clang driver and I encounter a strange bug.
> 
> It occurs when I used the getSize function from the SymbolRef class.
> 
> On iOS, the number returned is not always correct (some function have the
right size).
Only ELF has usable size information, MachO and COFF do not. That's also the
reason why SymbolRef::getSize doesn't exist anymore in LLVM trunk. To get
the real sizes you can either use the address trick used by MachODump.cpp or use
computeSymbolSizes which wraps this in a convenient API.

- Ben
> 
> Sadly,
> 
> This is my code (at the end of the main function into driver.cpp) :
> 
> ####
> 
> ErrorOr<OwningBinary<Binary>> BinaryOrErr = createBinary(file);
> if (std::error_code ec = BinaryOrErr.getError()) {
>  return ec.value();
> }
> 
> Binary &Binary = *BinaryOrErr.get().getBinary();
> object::ObjectFile *objfile;
> 
> objfile = dyn_cast<ObjectFile>(&Binary);
> 
> for (const SymbolRef &Symbol : objfile->symbols()) {
> uint64_t size;
>  Symbol.getAddress(size);
> 
> }
> 
> ####
> 
> During my previous search, I check machODump.cpp in order to see of the
list all the function.
> 
> They never use the getSize() but they use the address (getAddress()) of the
next function.
> 
> Does anyone have ever heard of a bug with this function or did I do
something wrong?
> 
> Greeting,
> 
> Johan Wehrli
> 
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Ok thanks for the answer. I will try the computeSymbolSizes.

Johan

> On 15 Jul 2015, at 18:07, Benjamin Kramer <benny.kra at gmail.com>
wrote:
> 
> 
>> On 15.07.2015, at 17:52, Wehrli Johan <johan.wehrli at
heig-vd.ch> wrote:
>> 
>> 
>> Hi everyone,
>> 
>> I’m currently playing with the clang driver and I encounter a strange
bug.
>> 
>> It occurs when I used the getSize function from the SymbolRef class.
>> 
>> On iOS, the number returned is not always correct (some function have
the right size).
> 
> Only ELF has usable size information, MachO and COFF do not. That's
also the reason why SymbolRef::getSize doesn't exist anymore in LLVM trunk.
To get the real sizes you can either use the address trick used by MachODump.cpp
or use computeSymbolSizes which wraps this in a convenient API.
> 
> - Ben
> 
>> 
>> Sadly,
>> 
>> This is my code (at the end of the main function into driver.cpp) :
>> 
>> ####
>> 
>> ErrorOr<OwningBinary<Binary>> BinaryOrErr =
createBinary(file);
>> if (std::error_code ec = BinaryOrErr.getError()) {
>> return ec.value();
>> }
>> 
>> Binary &Binary = *BinaryOrErr.get().getBinary();
>> object::ObjectFile *objfile;
>> 
>> objfile = dyn_cast<ObjectFile>(&Binary);
>> 
>> for (const SymbolRef &Symbol : objfile->symbols()) {
>> uint64_t size;
>> Symbol.getAddress(size);
>> 
>> }
>> 
>> ####
>> 
>> During my previous search, I check machODump.cpp in order to see of the
list all the function.
>> 
>> They never use the getSize() but they use the address (getAddress()) of
the next function.
>> 
>> Does anyone have ever heard of a bug with this function or did I do
something wrong?
>> 
>> Greeting,
>> 
>> Johan Wehrli
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>