RealView Compilation Tools - ARM Information Center

Compiler Command-line Options
Usage
You can perform multiple compilations using the same feedback file. The compiler
places each unused function identified in the feedback file into its own ELF section in
the corresponding object file.
The feedback file contains information about a previous build. Because of this:
• The feedback file might be out of date. That is, a function previously identified as
being unused might be used in the current source code. The linker removes the
code for an unused function only if it is not used in the current source code.
Note
— For this reason, eliminating unused functions using linker feedback is a safe
optimization, but there might be a small impact on code size.
— The usage requirements for reducing compilation required for interworking
are more strict than for eliminating unused functions. If you are reducing
interworking compilation, it is critical that you keep your feedback file up
to date with the source code that it was generated from.
• You have to do a full compile and link at least twice to get the maximum benefit
from linker feedback. However, a single compile and link using feedback from a
previous build is usually sufficient.
See also
• --split_sections on page 2-118
• --feedback_type=type on page 2-39 in the Linker Reference Guide
• Using linker feedback on page 2-26 in the Compiler User Guide.
2.1.70 --force_new_nothrow, --no_force_new_nothrow
This option controls the behavior of new expressions in C++.
The C++ standard states that only a no throw operator new declared with throw() is
permitted to return NULL on failure. Any other operator new is never permitted to return
NULL and the default operator new throws an exception on failure.
If you use --force_new_nothrow, the compiler treats expressions such as new
T(...args...), that use the global ::operator new or ::operator new[], as if they are new
(std::nothrow) T(...args...).
--force_new_nothrow also causes any class-specific operator new or any overloaded
global operator new to be treated as no throw.
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