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LLVM: fix tripping assertions

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Packed structs were tripping an LLVM assertion due to calling
`LLVMConstZExt` from i16 to i16. Solved by using instead
`LLVMConstZExtOrBitCast`.

Unions were tripping an LLVM assertion due to a typo using the union
llvm type to construct an integer value rather than the tag type.
This commit is contained in:
Andrew Kelley
2022-03-01 14:56:43 -07:00
parent 1b194931b0
commit f6aaab9406
3 changed files with 12 additions and 7 deletions
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12
src/codegen/llvm.zig
View File

@@ -1464,9 +1464,8 @@ pub const DeclGen = struct {
if (struct_obj.layout == .Packed) {
const target = dg.module.getTarget();
var int_ty_buf: Type.Payload.Bits = undefined;
const int_ty = struct_obj.packedIntegerType(target, &int_ty_buf);
const int_llvm_ty = try dg.llvmType(int_ty);
const big_bits = struct_obj.packedIntegerBits(target);
const int_llvm_ty = dg.context.intType(big_bits);
const fields = struct_obj.fields.values();
comptime assert(Type.packed_struct_layout_version == 2);
var running_int: *const llvm.Value = int_llvm_ty.constNull();
@@ -1483,7 +1482,10 @@ pub const DeclGen = struct {
const small_int_ty = dg.context.intType(ty_bit_size);
const small_int_val = non_int_val.constBitCast(small_int_ty);
const shift_rhs = int_llvm_ty.constInt(running_bits, .False);
const extended_int_val = small_int_val.constZExt(int_llvm_ty);
// If the field is as large as the entire packed struct, this
// zext would go from, e.g. i16 to i16. This is legal with
// constZExtOrBitCast but not legal with constZExt.
const extended_int_val = small_int_val.constZExtOrBitCast(int_llvm_ty);
const shifted = extended_int_val.constShl(shift_rhs);
running_int = running_int.constOr(shifted);
running_bits += ty_bit_size;
@@ -4830,7 +4832,7 @@ pub const FuncGen = struct {
index_type.constInt(@boolToInt(layout.tag_align < layout.payload_align), .False),
};
const field_ptr = self.builder.buildInBoundsGEP(casted_ptr, &indices, indices.len, "");
const llvm_tag = union_llvm_ty.constInt(extra.field_index, .False);
const llvm_tag = tag_llvm_ty.constInt(extra.field_index, .False);
const store_inst = self.builder.buildStore(llvm_tag, field_ptr);
store_inst.setAlignment(union_obj.tag_ty.abiAlignment(target));
}

3
src/codegen/llvm/bindings.zig
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@@ -157,6 +157,9 @@ pub const Value = opaque {
pub const constZExt = LLVMConstZExt;
extern fn LLVMConstZExt(ConstantVal: *const Value, ToType: *const Type) *const Value;
pub const constZExtOrBitCast = LLVMConstZExtOrBitCast;
extern fn LLVMConstZExtOrBitCast(ConstantVal: *const Value, ToType: *const Type) *const Value;
pub const constNot = LLVMConstNot;
extern fn LLVMConstNot(ConstantVal: *const Value) *const Value;

4
test/behavior/struct.zig
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@@ -871,10 +871,10 @@ test "non-packed struct with u128 entry in union" {
var sx: S = undefined;
var s = &sx;
try std.testing.expect(@ptrToInt(&s.f2) - @ptrToInt(&s.f1) == @offsetOf(S, "f2"));
try expect(@ptrToInt(&s.f2) - @ptrToInt(&s.f1) == @offsetOf(S, "f2"));
var v2 = U{ .Num = 123 };
s.f2 = v2;
try std.testing.expect(s.f2.Num == 123);
try expect(s.f2.Num == 123);
}
test "packed struct field passed to generic function" {