Inspect Manual

Using Inspect With TNS/R Native Programs

Inspect Manual—429164-006

17-3

Optimization Levels

To debug a TNS/R program that contains position-independent code (PIC), you must

use Visual Inspect.

Optimization Levels

Debugging TNS/R native processes differs from debugging TNS or accelerated

processes. Unlike TNS and accelerated processes, TNS/R native processes do not

maintain the TNS process environment, such as the TNS environment registers.

The C, C++, and pTAL compilers support three optimization levels: 0, 1, and 2.

Source-level debugging capabilities are directly related to the optimization level of the

compiler.

Optimize 0

At this level of optimization, no optimizations occur. There is no scheduling, all delay

slots are filled with a NOP, and memory is immediately updated after calculations.

That is, variables are placed in registers, necessary calculations are performed, and

the variables are immediately updated.

Optimize 1

At this level of optimization, as many delay slots as possible are filled and updating of

memory is sometimes deferred because of forward motion of store instructions by the

scheduler.

Optimize 1 offers full debugging support. However, statement boundaries can be

blurred. Inspect will choose a sensible location when you request a breakpoint on a

source statement. Inspects statement boundaries do not necessarily coincide directly

with source statements and will emit a warning when a process is held (e.g., hits a

breakpoint) at a statement for which some code associated with a previous source

statement, e.g. a store instruction, has yet to execute.

Optimize 2

At this level of optimization, the compiler performs all of its possible optimizations–

algorithm cannot be tracked with the current debugger symbol table information.

Practically, there is no symbolic debugging support for Optimize 2.