Looks good, except the comment in ObjectFileELF::SetLoadAddress(...) is out of 
date:

+                // Iterate through the object file sections to find the
+                // first section that starts of file offset zero and that
+                // has bytes in the file...

This should probably be changed to reflect the check for SHF_ALLOC...


On Feb 5, 2014, at 11:22 AM, Steve Pucci <[email protected]> wrote:

> Oops, sorry.  Here it is...
> 
> 
> On Wed, Feb 5, 2014 at 11:15 AM, Greg Clayton <[email protected]> wrote:
> Can you attach the update patch file?
> 
> On Feb 5, 2014, at 10:23 AM, Steve Pucci <[email protected]> wrote:
> 
> > OK, updated patch attached.  Responses to the questions inline below.
> >
> > Thanks,
> >    Steve
> >
> >
> > On Wed, Jan 29, 2014 at 4:16 PM, Greg Clayton <[email protected]> wrote:
> > So a few questions:
> >
> > 1 - Does anyone use the "link_map_addr" parameter that is being sent to 
> > many of the functions that were moved into DynamicLoader? I didn't see any. 
> > Please remove this argument if possible.
> >
> > It turns out this *is* used in 
> > DynamicLoaderPOSIXDYLD::UpdateLoadedSections(), so I left it in there and 
> > in the routine that calls it (LoadModuleAtAddress), but it was possible to 
> > remove it from UpdateLoadedSectionsCommon so I did that.
> >
> > 2 - ReadInt() isn't correct for all systems:
> >
> > static int ReadInt(Process *process, addr_t addr)
> > {
> >     Error error;
> >     int value = (int)process->ReadUnsignedIntegerFromMemory(addr, 
> > sizeof(uint32_t), 0, error);
> >
> > See the "sizeof(uint32_t)"? We will want to get the size of an "int" for 
> > the process that is being run if this function really does need to get a 
> > "int" from the debugger. So this sizeof() needs to be changed to get the 
> > actual size of a type "int" via:
> >
> > ClangASTContext *ast = m_process->GetTarget().GetScratchClangASTContext();
> > ClangASTType int_type = ast->GetBasicType (eBasicTypeInt);
> > uint64_t int_size = int_type.GetByteSize();
> >
> > Or this function might be more useful if we pass in the size of the integer 
> > we need?
> >
> > Investigating this revealed what appears to be a bug on big-endian 64-bit 
> > Linux platforms, but I'm decoupling that bug fix from this patch, as this 
> > patch is supposed to be functionally a no-op.  I've taken your suggestion 
> > that the size of the int should be passed in, but for now the caller passes 
> > in "4" as that's equivalent to the code that was there before.
> >
> > 3 - The DynamicLoader class has a m_process member variable so the "Process 
> > *process" argument doesn't need to be passed into the following functions:
> >         int DynamicLoader::ReadInt(Process *process, addr_t addr);
> >         addr_t DynamicLoader::ReadPointer(Process *process, addr_t addr);
> >
> > I made these methods non-static and removed the process parameter as you 
> > suggested.
> >
> > On Jan 29, 2014, at 1:45 PM, Steve Pucci <[email protected]> wrote:
> >
> > > OK, that seemed to work, at least on my simple shared-library testcase on 
> > > Ubuntu, which invokes the new code in ObjectFileELF::SetLoadAddress().
> > >
> > > Updated full patch attached.
> > >
> > >
> > >
> > >
> > > On Tue, Jan 28, 2014 at 7:19 AM, Steve Pucci <[email protected]> wrote:
> > > OK, great, thanks Greg, I'll give it a go.
> > >
> > >  - Steve
> > >
> > >
> > > On Mon, Jan 27, 2014 at 4:31 PM, Greg Clayton <[email protected]> wrote:
> > > The first thing to do is just look at the section that has address of 
> > > zero and see if it has any bits that the other don't or vice versa.
> > >
> > > I think the bit you are looking for is SHF_ALLOC.
> > >
> > > The "sh_flags" from the ELF section are indeed placed in the 
> > > lldb_private::Section flags, so you should be able to do:
> > >
> > > for (section : sections)
> > > {
> > >     if (section->Test(SHF_ALLOC))
> > >     {
> > >         // Load this section
> > >     }
> > > }
> > >
> > >
> > >
> > >
> > >
> > > On Jan 27, 2014, at 4:23 PM, Steve Pucci <[email protected]> wrote:
> > >
> > > > OK, I understand, though I may need some help from someone with 
> > > > interpreting Section headers for Elf.  I'll let this group know if I 
> > > > have questions.
> > > >
> > > > Thanks again,
> > > >    Steve
> > > >
> > > >
> > > > On Mon, Jan 27, 2014 at 4:17 PM, Greg Clayton <[email protected]> 
> > > > wrote:
> > > >
> > > > On Jan 27, 2014, at 4:02 PM, Steve Pucci <[email protected]> wrote:
> > > >
> > > > > Thanks, Greg.
> > > > >
> > > > > I think it all makes sense, except for one bit:
> > > > >
> > > > > In ObjectFileELF::SetLoadAddress(), are you proposing I simply call 
> > > > > Module::SetLoadAddress as it exists today?  That method walks through 
> > > > > all sections and checks only section_sp->IsThreadSpecific() to decide 
> > > > > whether to load the section, and there's no place to insert an 
> > > > > ELF-specific check of the section to see if it's loadable.  Is that 
> > > > > what you meant, or are you suggesting something else?
> > > >
> > > > Something else. When the ObjectFileELF parser parses the section 
> > > > headers, it places the flags (or it should if it isn't) into the flags 
> > > > field of the lldb_private::Section. So it should be able to use the 
> > > > flags from its sections to correctly in each lldb_private::Section, and 
> > > > correctly interpret them to know which sections need to be loaded and 
> > > > which don't. So let the ELF plugin that created the sections correctly 
> > > > interpret the flags it put into the sections.
> > > >
> > > > We then will need to change the Module::SetLoadAddress() to call this 
> > > > new ObjectFile function.
> > > >
> > > > >
> > > > > Instead of that I could have ObjectFileELF::SetLoadAddress iterate 
> > > > > through the sections as UpdateLoadedSectionsCommon does below, OR I 
> > > > > could somehow provide a callback to be called from 
> > > > > Module::SetLoadAddress (perhaps by passing in the ObjectFile*).
> > > >
> > > > It should all be done in the ObjectFileELF::SetLoadAddress function.
> > > >
> > > > >
> > > > > Thanks,
> > > > >   Steve
> > > > >
> > > > >
> > > > >
> > > > > On Mon, Jan 27, 2014 at 3:14 PM, Greg Clayton <[email protected]> 
> > > > > wrote:
> > > > >
> > > > > On Jan 27, 2014, at 3:05 PM, Greg Clayton <[email protected]> wrote:
> > > > >
> > > > > > Looks ok except for:
> > > > > >
> > > > > > This is ELF specific with the file address of zero, and it probably 
> > > > > > should more be done via flags and asking the section if it is 
> > > > > > loadable:
> > > > > >
> > > > > > +void
> > > > > > +DynamicLoader::UpdateLoadedSectionsCommon(ModuleSP module, addr_t 
> > > > > > link_map_addr, addr_t base_addr)
> > > > > > +{
> > > > > > +    Target &target = m_process->GetTarget();
> > > > > > +    const SectionList *sections = GetSectionListFromModule(module);
> > > > > > +
> > > > > > +    assert(sections && "SectionList missing from loaded module.");
> > > > > > +
> > > > > > +    const size_t num_sections = sections->GetSize();
> > > > > > +
> > > > > > +    for (unsigned i = 0; i < num_sections; ++i)
> > > > > > +    {
> > > > > > +        SectionSP section_sp (sections->GetSectionAtIndex(i));
> > > > > > +        lldb::addr_t new_load_addr = section_sp->GetFileAddress() 
> > > > > > + base_addr;
> > > > > > +
> > > > > > +        // If the file address of the section is zero then this is 
> > > > > > not an
> > > > > > +        // allocatable/loadable section (property of ELF sh_addr). 
> > > > > >  Skip it.
> > > > > > +        if (new_load_addr == base_addr)
> > > > > > +            continue;
> > > > > > +
> > > > > > +        target.SetSectionLoadAddress(section_sp, new_load_addr);
> > > > > > +    }
> > > > > > +}
> > > > > >
> > > > > >
> > > > > > There is also a module function that does something similar to 
> > > > > > this, without the looking for the zero address:
> > > > > >
> > > > > > bool
> > > > > > Module::SetLoadAddress (Target &target, lldb::addr_t offset, bool 
> > > > > > &changed);
> > > > > >
> > > > > > So I would propose the following:
> > > > > >
> > > > > > Update DynamicLoader::UpdateLoadedSectionsCommon() to call into a 
> > > > > > new function that is a virtual function in ObjectFile:
> > > > > >
> > > > > > virtual bool SetLoadAddress (addr_t base_addr)
> > > > > > {
> > > > > >    return false;
> > > > > > }
> > > > > >
> > > > > > Then each object file (ObjectFileELF in your case) can choose to do 
> > > > > > the loading correctly given a single "base_addr":
> > > > > >
> > > > > > bool
> > > > > > ObjectFileELF::SetLoadAddress (addr_t base_addr)
> > > > > > {
> > > > > > }
> > > > > >
> > > > > > Then in ObjectFileELF::SetLoadAddress() you can use the section 
> > > > > > flags that were saved in the lldb_private::Section to properly 
> > > > > > determine which sections are loadable and which aren't. This 
> > > > > > function is for a rigid slide of all loadable sections.
> > > > > >
> > > > > > Does that make sense?
> > > > >
> > > > > I forgot the SetLoadAddress needs a target, and each object file 
> > > > > already knows its module, so that doesn't need to be passed, it can 
> > > > > be retrieved via the getter function:
> > > > >
> > > > > virtual bool SetLoadAddress (Target &target, addr_t base_addr)
> > > > > {
> > > > >    return false;
> > > > > }
> > > > >
> > > > > Then each object file (ObjectFileELF in your case) can choose to do 
> > > > > the loading correctly given a single "base_addr":
> > > > >
> > > > > bool
> > > > > ObjectFileELF::SetLoadAddress (Target &target, addr_t base_addr)
> > > > > {
> > > > >      ModuleSP module_sp = GetModule();
> > > > >      if (module_sp)
> > > > >      {
> > > > >          ....
> > > > >      }
> > > > > }
> > > > >
> > > > >
> > > > >
> > > > > > Greg
> > > > > >
> > > > > >
> > > > > >
> > > > > > On Jan 27, 2014, at 2:32 PM, Steve Pucci <[email protected]> wrote:
> > > > > >
> > > > > >> Hi,
> > > > > >>
> > > > > >> I'd like to have access to a number of methods in 
> > > > > >> DynamicLoaderPOSIXDYLD from the new class I'm working on, 
> > > > > >> DynamicLoaderGDBServer.  These methods have no dependency on 
> > > > > >> DynamicLoaderPOSIXDYLD, with two exceptions noted below, so I'm 
> > > > > >> proposing to move them into the base class DynamicLoader.
> > > > > >>
> > > > > >> The two exceptions are the methods UpdateLoadedSections and 
> > > > > >> UnloadSections; in each case there is one line of code that is 
> > > > > >> special to the derived class, and the rest of the code in the 
> > > > > >> method is generic to the base class.  In each case I created a 
> > > > > >> XXXCommon() method on the base class with the common code, and 
> > > > > >> created a virtual method XXX() on the base class, which in 
> > > > > >> DynamicLoaderPOSIXDYLD will call the common code and then execute 
> > > > > >> its one line of specialized code.
> > > > > >>
> > > > > >> This patch is intended to have no functional difference 
> > > > > >> whatsoever.  All 276 tests that are enabled for Ubuntu pass 
> > > > > >> successfully.
> > > > > >>
> > > > > >> Thanks,
> > > > > >>   Steve
> > > > > >>
> > > > > >>
> > > > > >> <patch-FactorDynamicLibrary.txt>_______________________________________________
> > > > > >> lldb-dev mailing list
> > > > > >> [email protected]
> > > > > >> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> > > > > >
> > > > > > _______________________________________________
> > > > > > lldb-dev mailing list
> > > > > > [email protected]
> > > > > > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> > >
> > > <patch-FactorDynamicLibrary-2.txt>
> 
> 
> <patch-FactorDynamicLibrary-3.txt>

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