[Info-vax] GCC for VMS, was: Re: fortran compiler roadmap?

[Stephen Hoffman]

On 2013-04-18 03:03:09 +0000, Craig A. Berry said:

> I asked specifically whether the code generators in GCC were up to 
> snuff for Alpha and Itanium, and he said yes; their Ada compiler 
> depends on this. ...

There were some few updates to the standard ELF and DWARF structures 
specifically for OpenVMS; the whole stack (debugger, analysis tools, 
linker, compiler back-ends) is different between Alpha and Itanium.  
The porting work involved a detailed engineering spec for just the ELF 
and DWARF changes, and the Linker was a large project in its own right, 
not to mention the other changes to all the other tools that touched 
the object code and executable code.  Can a compiler get away without 
these updates?  Probably.  Depending on what other parts of VMS you're 
using, sure.

Start with the calling standard here 
<http://h71000.www7.hp.com/openvms/whitepapers/index.html>, and 
probably also read the floating point information.

> And then you have a compiler with no debugger, so you either spend lots
> of time in the entrails of the compiler making it produce what the
> OpenVMS debugger expects, or you port gdb, or write you're own
> debugger.

lldb is also doing pretty well, if you head down the llvm path and not 
the gcc path.  But with either compiler tool chain, you're not going to 
play well in the mixed-language environment unless the compiler 
generates the appropriate debugger symbol table records, etc.


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