Using Makefiles With Program-Wide Optimizations For Common Development Tasks - Intel i960 User Manual

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4-10
i960 Processor Compiler User's Guide
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The global decision-making and optimization step manages the results
of previous work in the PDB so that all previously generated modules
are reused whenever possible. The system keeps multiple sets
(currently, two) of the most recently used substitution modules in the
PDB, indexed by the substitutions that generated them. The makefile
is not aware of this management task, and is simpler as a result.
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Even though program-wide optimizations can potentially trigger large
quantities of compilation and optimization work at link time, the
majority of this work usually occurs only the first time the program is
linked with a particular set of substitutions, or on the first link after
major changes are made to the program.
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The automatic management of substitution modules (defined in the
Selecting Modules for Optimization with Substitution Specifications
section) greatly simplifies some development tasks that are difficult
for users in an ordinary environment, such as maintaining both debug
and optimized versions of the object modules for a program. Given
modules already compiled with the
alternate program load module versions built efficiently by simply
invoking the linker with appropriate
See the next section for examples of using the sample makefile to
automate program-wide optimizations.
Using Makefiles with Program-wide Optimizations
for Common Development Tasks
Building an Optimized Program without Profiling
Using the example makefile, if you want to obtain a program built with
program-wide optimizations, pass the options you want through the
macro when invoking the make tool. For example, if you want level
optimization, use:
make SUBST=O5
option, users can have
fdb
options.
gcdm,subst
SUBST
O5