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codegen: fix packed byte-aligned relocations

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Closes #23131
This commit is contained in:
Jacob Young
2025-03-22 21:56:32 -04:00
committed by Andrew Kelley
parent f45f9649e3
commit 6705cbd5eb
8 changed files with 40 additions and 32 deletions
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25
src/codegen.zig
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@@ -23,10 +23,7 @@ const Zir = std.zig.Zir;
const Alignment = InternPool.Alignment;
const dev = @import("dev.zig");
pub const CodeGenError = error{
OutOfMemory,
/// Compiler was asked to operate on a number larger than supported.
Overflow,
pub const CodeGenError = GenerateSymbolError || error{
/// Indicates the error is already stored in Zcu `failed_codegen`.
CodegenFail,
};
@@ -177,6 +174,8 @@ pub const GenerateSymbolError = error{
OutOfMemory,
/// Compiler was asked to operate on a number larger than supported.
Overflow,
/// Compiler was asked to produce a non-byte-aligned relocation.
RelocationNotByteAligned,
};
pub fn generateSymbol(
@@ -481,12 +480,18 @@ pub fn generateSymbol(
// pointer may point to a decl which must be marked used
// but can also result in a relocation. Therefore we handle those separately.
if (Type.fromInterned(field_ty).zigTypeTag(zcu) == .pointer) {
const field_size = math.cast(usize, Type.fromInterned(field_ty).abiSize(zcu)) orelse
return error.Overflow;
var tmp_list = try std.ArrayListUnmanaged(u8).initCapacity(gpa, field_size);
defer tmp_list.deinit(gpa);
try generateSymbol(bin_file, pt, src_loc, Value.fromInterned(field_val), &tmp_list, reloc_parent);
@memcpy(code.items[current_pos..][0..tmp_list.items.len], tmp_list.items);
const field_offset = std.math.divExact(u16, bits, 8) catch |err| switch (err) {
error.DivisionByZero => unreachable,
error.UnexpectedRemainder => return error.RelocationNotByteAligned,
};
code.items.len = current_pos + field_offset;
// TODO: code.lockPointers();
defer {
assert(code.items.len == current_pos + field_offset + @divExact(target.ptrBitWidth(), 8));
// TODO: code.unlockPointers();
code.items.len = current_pos + abi_size;
}
try generateSymbol(bin_file, pt, src_loc, Value.fromInterned(field_val), code, reloc_parent);
} else {
Value.fromInterned(field_val).writeToPackedMemory(Type.fromInterned(field_ty), pt, code.items[current_pos..], bits) catch unreachable;
}