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21.4.1 AArch64

When GDB is debugging the AArch64 architecture, it provides the following special commands:

set debug aarch64

This command determines whether AArch64 architecture-specific debugging messages are to be displayed.

show debug aarch64

Show whether AArch64 debugging messages are displayed.

21.4.1.1 AArch64 SVE.

When GDB is debugging the AArch64 architecture, if the Scalable Vector Extension (SVE) is present, then GDB will provide the vector registers $z0 through $z31, vector predicate registers $p0 through $p15, and the $ffr register. In addition, the pseudo register $vg will be provided. This is the vector granule for the current thread and represents the number of 64-bit chunks in an SVE z register.

If the vector length changes, then the $vg register will be updated, but the lengths of the z and p registers will not change. This is a known limitation of GDB and does not affect the execution of the target process.

21.4.1.2 AArch64 Pointer Authentication.

When GDB is debugging the AArch64 architecture, and the program is using the v8.3-A feature Pointer Authentication (PAC), then whenever the link register $lr is pointing to an PAC function its value will be masked. When GDB prints a backtrace, any addresses that required unmasking will be postfixed with the marker [PAC]. When using the MI, this is printed as part of the addr_flags field.