DoxigAlpha
std › debug.Dwarf › scanCieFdeInfo

scanCieFdeInfo

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

Function parameters

Parameters

#
di:*Dwarf
base_address:usize

Type definitions in this namespace

Types

#
ExceptionFrameHeader
This represents the decoded .eh_frame_hdr header

Initialize DWARF info.

Functions

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open
Initialize DWARF info.
findCompileUnit
TODO: change this to binary searching the sorted compile unit list
scanAllUnwindInfo
If `.eh_frame_hdr` is present, then only the header needs to be parsed.
scanCieFdeInfo
Scan `.eh_frame` and `.debug_frame` and build a sorted list of FDEs for binary searching during
compactUnwindToDwarfRegNumber
Returns the DWARF register number for an x86_64 register number found in compact unwind info
bad
This function is to make it handy to comment out the return and make it

Error sets in this namespace

Error Sets

#

= [_]?Section{null} ** num_sections

Values

#
null_section_array
= [_]?Section{null} ** num_sections

Source

Implementation

#
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);
        }
    }
}