Implement ``-mforce-l32`` Target-Specific Option
The Xtensa backend gained a ``-mforce-l32`` option to allow sub-word reads from instruction memory even in generic address spaces or without the ``force_l32``…
The Xtensa backend gained a -mforce-l32 command line option. This option enables sub-word reads from instruction memory regions, even in generic address spaces or when the force_l32 attribute is not present. This can be useful when reading data such as constant tables or string literals from instruction memory.
In Details
This adds the Xtensa-specific -mforce-l32 command-line option, which interacts with the __force_l32 named address space and the force_l32 attribute. These features are used when the memory regions for placing machine instructions are not configured as "unified". The option allows sub-word reading from the instruction memory area even in the generic address spaces.
For Context
Some architectures, like Xtensa, have separate address spaces for instructions and data. Normally, code loads data (e.g. from a string literal) using data-access instructions. However, if the memory regions are not configured as "unified", special instructions are needed to load data from instruction memory. The -mforce-l32 option enables this behavior.