Debugging with GDB Manual The GNU Source-Level Debugger (769148-001, March 2014)

When GDB has no debug information; it does not know where the arguments are located or even
the type of the arguments. GDB cannot infer this in an optimized, non-debug executable.
However, for integer arguments you can and the first few parameters for the top-of- stack frame
by looking at the registers. On PA-RISC systems, the first parameter will be in $r26, the second
in $r25, and so on. On IPF systems, the first few parameters will be in $gr32 and $gr33.
Debugging optimized code
HP WDB supports debugging of optimized code (compiled with both -g and -O) for HP aC++, HP
ANSI C and HP WDB for HP Itanium.
The following commands evaluate the name of a function and hence are affected by the optimization
level of the program being debugged (in particular, due to inlining):
• break
• call
• clear
• disassem
• list
The following commands evaluate an expression referring to variables in the user pro- gram and
hence, are affected by the optimization level of the program being debugged:
• break
• call
• cond
• jump
• return
• print
• set <var>
• watch
• whatis x
NOTE: The break and call commands involve evaluation of both the name of a function and
an expression.
The following commands are also affected by the optimization level of the program being debugged:
• backtrace
• display
• down
• finish
• frame
• info *
• next
• step
• tbreak
• rbreak
• up
172 HP-UX Configuration-Specific Information