Function scanCieFdeInfo [src]

Scan .eh_frame and .debug_frame and build a sorted list of FDEs for binary searching during unwinding.

Prototype

pub fn scanCieFdeInfo(di: *Dwarf, allocator: Allocator, base_address: usize) !void

Parameters

di: *Dwarfallocator: Allocatorbase_address: usize

Source

  pub fn scanCieFdeInfo(di: *Dwarf, allocator: Allocator, base_address: usize) !void {
    const frame_sections = [2]Section.Id{ .eh_frame, .debug_frame };
    for (frame_sections) |frame_section| {
        if (di.section(frame_section)) |section_data| {
            var fbr: FixedBufferReader = .{ .buf = section_data, .endian = di.endian };
            while (fbr.pos < fbr.buf.len) {
                const entry_header = try EntryHeader.read(&fbr, null, frame_section);
                switch (entry_header.type) {
                    .cie => {
                        const cie = try CommonInformationEntry.parse(
                            entry_header.entry_bytes,
                            di.sectionVirtualOffset(frame_section, base_address).?,
                            true,
                            entry_header.format,
                            frame_section,
                            entry_header.length_offset,
                            @sizeOf(usize),
                            di.endian,
                        );
                        try di.cie_map.put(allocator, entry_header.length_offset, cie);
                    },
                    .fde => |cie_offset| {
                        const cie = di.cie_map.get(cie_offset) orelse return bad();
                        const fde = try FrameDescriptionEntry.parse(
                            entry_header.entry_bytes,
                            di.sectionVirtualOffset(frame_section, base_address).?,
                            true,
                            cie,
                            @sizeOf(usize),
                            di.endian,
                        );
                        try di.fde_list.append(allocator, fde);
                    },
                    .terminator => break,
                }
            }

            std.mem.sortUnstable(FrameDescriptionEntry, di.fde_list.items, {}, struct {
                fn lessThan(ctx: void, a: FrameDescriptionEntry, b: FrameDescriptionEntry) bool {
                    _ = ctx;
                    return a.pc_begin < b.pc_begin;
                }
            }.lessThan);
        }
    }
}  