tiny.tldr.formats.elf.relocation.target

1pub const target = @import("target.zig");

1const std = @import("std");2const root = @import("../../../root.zig");3const elf = @import("../root.zig");45const model = root.model;6const addressing = elf.addressing;7const ObjectFile = elf.parser.ObjectFile;8const ObjectLayout = elf.layout.ObjectLayout;9const OutputSection = elf.layout.OutputSection;10const GlobalSymbol = elf.layout.GlobalSymbol;11const Rela = elf.format.Rela;12const SymbolAddressCache = addressing.Cache;13const SymbolCacheAccess = addressing.Access;14const RelocationTarget = addressing.Target;15const relocationTargetAddress = addressing.relocationTarget;16const symbolTlsOffset = addressing.tlsOffset;1718pub fn cached(19    comptime cache_access: SymbolCacheAccess,20    objects: []const ObjectFile,21    layouts: []const ObjectLayout,22    output_sections: []const OutputSection,23    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),24    symbol_addresses: *SymbolAddressCache,25    object_index: usize,26    symbol_index: usize,27    relocation: Rela,28    needs_size: bool,29    tls_offset: bool,30    target_cache: *Cache,31) model.Error!RelocationTarget {32    const target = target_cache.get(object_index, symbol_index, relocation.addend, needs_size, tls_offset) orelse blk: {33        const resolved = if (tls_offset)34            RelocationTarget{35                .address = @intCast(try symbolTlsOffset(objects, layouts, output_sections, globals, symbol_addresses, object_index, symbol_index)),36                .addend = relocation.addend,37                .size = 0,38            }39        else40            try relocationTargetAddress(41                cache_access,42                objects,43                layouts,44                output_sections,45                globals,46                symbol_addresses,47                object_index,48                symbol_index,49                relocation,50                needs_size,51            );52        target_cache.put(object_index, symbol_index, relocation.addend, needs_size, tls_offset, resolved);53        break :blk resolved;54    };55    return target;56}5758pub fn cachedOrSkip(59    comptime cache_access: SymbolCacheAccess,60    objects: []const ObjectFile,61    layouts: []const ObjectLayout,62    output_sections: []const OutputSection,63    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),64    symbol_addresses: *SymbolAddressCache,65    object_index: usize,66    symbol_index: usize,67    relocation: Rela,68    needs_size: bool,69    tls_offset: bool,70    ignore_missing_target: bool,71    target_cache: *Cache,72) model.Error!?RelocationTarget {73    return cached(74        cache_access,75        objects,76        layouts,77        output_sections,78        globals,79        symbol_addresses,80        object_index,81        symbol_index,82        relocation,83        needs_size,84        tls_offset,85        target_cache,86    ) catch |err| switch (err) {87        error.MissingSection => if (ignore_missing_target) return null else return err,88        else => return err,89    };90}9192pub const Cache = struct {93    const entry_count = 64;94    const invalid_object_index = std.math.maxInt(usize);9596    entries: [entry_count]Entry = @splat(Entry{}),9798    const Entry = struct {99        object_index: usize = invalid_object_index,100        symbol_index: usize = 0,101        addend: i64 = 0,102        needs_size: bool = false,103        tls_offset: bool = false,104        target: RelocationTarget = .{ .address = 0, .addend = 0, .size = 0 },105    };106107    pub fn get(108        self: *const Cache,109        object_index: usize,110        symbol_index: usize,111        addend: i64,112        needs_size: bool,113        tls_offset: bool,114    ) ?RelocationTarget {115        const entry = self.entries[indexFor(object_index, symbol_index, addend, needs_size, tls_offset)];116        if (entry.object_index != object_index) return null;117        if (entry.symbol_index != symbol_index) return null;118        if (entry.addend != addend) return null;119        if (entry.needs_size != needs_size) return null;120        if (entry.tls_offset != tls_offset) return null;121        return entry.target;122    }123124    pub fn put(125        self: *Cache,126        object_index: usize,127        symbol_index: usize,128        addend: i64,129        needs_size: bool,130        tls_offset: bool,131        target: RelocationTarget,132    ) void {133        self.entries[indexFor(object_index, symbol_index, addend, needs_size, tls_offset)] = .{134            .object_index = object_index,135            .symbol_index = symbol_index,136            .addend = addend,137            .needs_size = needs_size,138            .tls_offset = tls_offset,139            .target = target,140        };141    }142143    fn indexFor(object_index: usize, symbol_index: usize, addend: i64, needs_size: bool, tls_offset: bool) usize {144        const addend_bits: u64 = @bitCast(addend);145        var hash = object_index *% 0x9e3779b1;146        hash ^= symbol_index *% 0x85ebca6b;147        hash ^= @as(usize, @truncate(addend_bits));148        if (needs_size) hash ^= 0xc2b2ae35;149        if (tls_offset) hash ^= 0x27d4eb2f;150        return hash & (entry_count - 1);151    }152};