i960 Processor Compiler User's Guide
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For ELF/DWARF, a debug level setting of g3 specifies all DWARF debug
information, including preprocessor macros in the debug information. If
your debugger (like gdb960) does not make use of preprocessor macro
information, you can save space in your object files by dropping to
ELF/DWARF debug level 2.
The
g (Debug) option does not inhibit optimization. When you specify the
g option but do not specify the O (Optimize) option, the optimization level
defaults to
O0.
Specifying an optimization level higher than
O0 can inhibit the
effectiveness of the symbolic debug information. For example, if you set
a breakpoint on a source line that has been removed during optimization,
the breakpoint is never hit. Or if you try to print the value of a variable
that has been optimized away, an erroneous value is displayed. In general,
as the optimization level increases, the reliability of the symbolic debug
information decreases.
When you are using the ELF object module format (
Felf), g causes the
compiler to produce DWARF debug information. This debug information
format is richer than that of other supported OMFs, and allows more
reliable debugging under optimization. However, even with DWARF,
there are situations where debugging behavior does not agree with the
debugging behavior of unoptimized code.
gcdm,
arg
[,
arg
]... (Decision Maker)
Invoke gcdm960
optimization decision
maker.
gcdm,
arg
[,
arg
]...
The gcdm option provides a high level of automation for whole-program
or profile-driven optimization processes. The compiler driver and the
linker both use the gcdm option and its arguments.
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