 RealView Linker and Utilities Guide | |
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RealView Linker and Utilities Guide
Preface Introduction The Linker Command Syntax Using the Basic Linker Functionality Specifying the image structure
Building blocks for objects and images Load view and execution view of an image Specifying an image memory map Image entry points Section placement Ordering input sections by attribute Using FIRST and LAST to place sections Aligning sections Ordering execution regions containing Thumb code Optimizations and modifications Common debug section elimination Common group or section elimination Unused section elimination Unused function elimination Linker feedback RW data compression PI to absolute veneers Veneer generation Reuse of veneers with overlay execution regions Branch inlining Using command-line options to create simple images Type 1, one load region and contiguous execution r Type 2, one load region and non contiguous executi Type 3, two load regions and non contiguous execut Using command-line options to handle C++ exception Getting information about images Using image-related information Accessing Image Symbols Using Scatter-loading Description Files Using the ARM Librarian Using fromelfCommon group or section elimination
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| Home > Using the Basic Linker Functionality > Optimizations and modifications > Common group or section elimination | |||
If there are inline functions or templates used in the C++ source, the ARM compiler generates complete objects for linking such that each object contains the out‑of‑line copies of inline functions and template functions that the object requires. When these functions are declared in a common header file, the functions might be defined many times in separate objects that are subsequently linked together. In order to eliminate duplicates, the compiler compiles these functions into separate instances of common code sections or groups.
It is possible that the separate instances of common code sections, or groups, are not identical. Some of the copies, for example, might be found in a library that has been built with different (but compatible) build options, different optimization, or different debug options.
If the copies are not identical, armlink retains the best available variant of each common code section, or group, based on the attributes of the input objects. armlink discards the rest.
If the copies are identical, armlink retains the first section or group located.
This optimization is controlled by linker options:
Use the
‑‑bestdebugoption to use the largest Comdat group (likely to give the best debug view).Use the
‑‑no_bestdebugoption to use the smallest Comdat group (likely to give the smallest code size). This is the default. In most cases, use of‑‑bestdebugis unlikely.Because
‑‑no_bestdebugis the default, the final image is the same regardless of whether you generate debug tables during compilation with‑‑debug.For more information, see:
Inlining in the Compiler User Guide
‑‑[no_]debug in the Compiler Reference Guide.
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