Restore the `-gz` option to the driver with some minor tweaks to handle
the additional case for `-Wa,--compress-debug-sections`.
This intends to make the compression of the debug information
controllable from the driver. The following is the behaviour:
-gz enable compression (ambiguous for format, will default to zlib-gnu)
-gz=none disable compression
-gz=zlib-gnu enable compression (deprecated GNU style zlib compression)
-gz=zlib enable compression (zlib based compression)
Although -Wa,-compress-debug-sections works, it should be discouraged
when using the driver to invoke the assembler. However, we permit the
assembler to accept the GNU as style argument --compress-debug-sections
to maintain compatibility.
Note, -gz/-gz= does *NOT* imply -g. That is, you need to additionally
specific -g for debug information to be generated.
llvm-svn: 306115
Saleem Abdulrasool