getRegDefaultValue
Returns the ABI-defined default value this register has in the unwinding table before running any of the CIE instructions. The DWARF spec defines these as having the .undefined rule by default, but allows ABI authors to override that.
Function parameters
Parameters
- reg_number:u8
- context:*UnwindContext
- out:[]u8
How is this different than `Module` when the host is Windows?
Types
- WindowsModule
- How is this different than `Module` when the host is Windows?
- VirtualMachine
- This is a virtual machine that runs DWARF call frame instructions.
Functions in this namespace
Functions
- readElfDebugInfo
- Reads debug info from an ELF file, or the current binary if none in specified.
- unwindFrameMachO
- Unwind a frame using MachO compact unwind info (from __unwind_info).
- stripInstructionPtrAuthCode
- Some platforms use pointer authentication - the upper bits of instruction pointers contain a signature.
- unwindFrameDwarf
- Unwind a stack frame using DWARF unwinding info, updating the register context.
- supportsUnwinding
- Tells whether unwinding for this target is *implemented* here in the Zig
Error sets in this namespace
Error Sets
Tells whether unwinding for the host is implemented.
Values
- supports_unwinding
- Tells whether unwinding for the host is implemented.
Source
Implementation
fn getRegDefaultValue(reg_number: u8, context: *UnwindContext, out: []u8) !void {
switch (builtin.cpu.arch) {
.aarch64, .aarch64_be => {
// Callee-saved registers are initialized as if they had the .same_value rule
if (reg_number >= 19 and reg_number <= 28) {
const src = try regBytes(context.thread_context, reg_number, context.reg_context);
if (src.len != out.len) return error.RegisterSizeMismatch;
@memcpy(out, src);
return;
}
},
else => {},
}
@memset(out, undefined);
}