-fpatchable-function-entry
Purpose
Generates an 8-word block before function entry and N-8 NOPs after function entry.
Syntax
Default
None.
Parameters
- N
- N-8 is the number of NOPs to be generated.
Usage
In Clang, the -fpatchable-function-entry=<N,M> can be used to generate M NOPs before function entry and N-M NOPs after function entry. This option is available in IBM® Open XL C/C++ for AIX® 17.1.2. However, the IBM implementation of this option differs from the generic Clang functionality in the following ways:
- M is required to be 8.
- Instead of generating M NOPs before the function entry, an 8-word block is
generated. This block contains 3.5 repetition of the
hotpatch
string, followed by an unconditional trap instruction to detect accidental branching to this area. - This functionality is available with the -ffunction-sections option starting from IBM Open XL C/C++ for AIX 17.1.2.2.
Predefined macros
None.
Related information
The "Clang command line argument reference" section in the Clang documentation