The string representation of the data layout is retrieved from the TargetData class (in main) and passed via global.params.dataLayout to the module. Since the gTargetData is also a global variable it makes no sense to pass this information using another global variable.
The D Programming Language
Compiler Front End Source
Copyright (c) 1999-2009, by Digital Mars
http://www.digitalmars.com
All Rights Reserved
This is the source code to the front end Digital Mars D compiler.
It covers the lexical analysis, parsing, and semantic analysis
of the D Programming Language defined in the documents at
http://www.digitalmars.com/d/
These sources are free, they are redistributable and modifiable
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version (attached as gpl.txt),
or the Artistic License (attached as artistic.txt).
The optimizer and code generator sources are
covered under a separate license, backendlicense.txt.
It does not apply to anything else distributed by Digital Mars,
including D compiler executables.
-Walter Bright
4b0c4bf4ae