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Add floating-point internal bit representation to TypeInfo #1139

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Add floating-point internal bit representation to TypeInfo #1139

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2 changes: 2 additions & 0 deletions src/codegen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6550,6 +6550,8 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
"\n"
" pub const Float = struct {\n"
" bits: u8,\n"
" exponent_bits: u8,\n"
" mantissa_bits: u8,\n"
" };\n"
"\n"
" pub const Pointer = struct {\n"
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50 changes: 48 additions & 2 deletions src/ir.cpp
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Expand Up @@ -16658,14 +16658,60 @@ static ConstExprValue *ir_make_type_info_value(IrAnalyze *ira, TypeTableEntry *t
result->special = ConstValSpecialStatic;
result->type = ir_type_info_get_type(ira, "Float");

ConstExprValue *fields = create_const_vals(1);
ConstExprValue *fields = create_const_vals(3);
result->data.x_struct.fields = fields;

uint8_t exponent_bits;
uint8_t mantissa_bits;
switch (type_entry->data.floating.bit_count) {
case 16:
exponent_bits = 5;
mantissa_bits = 10;
break;

case 32:
exponent_bits = 8;
mantissa_bits = 23;
break;

case 64:
exponent_bits = 11;
mantissa_bits = 52;
break;

// extended precision. This may have an explicit integer
// bit instead of a hidden bit as in standard IEEE variants.
case 80:
exponent_bits = 15;
mantissa_bits = 64;
break;

case 128:
exponent_bits = 15;
mantissa_bits = 112;
break;

default:
zig_unreachable();
}

assert(exponent_bits + mantissa_bits + 1 == type_entry->data.floating.bit_count);

// bits: u8
ensure_field_index(result->type, "bits", 0);
fields[0].special = ConstValSpecialStatic;
fields[0].type = ira->codegen->builtin_types.entry_u8;
bigint_init_unsigned(&fields->data.x_bigint, type_entry->data.floating.bit_count);
bigint_init_unsigned(&fields[0].data.x_bigint, type_entry->data.floating.bit_count);
// exponent_bits: u8
ensure_field_index(result->type, "exponent_bits", 1);
fields[1].special = ConstValSpecialStatic;
fields[1].type = ira->codegen->builtin_types.entry_u8;
bigint_init_unsigned(&fields[1].data.x_bigint, exponent_bits);
// mantissa_bits: u8
ensure_field_index(result->type, "mantissa_bits", 2);
fields[2].special = ConstValSpecialStatic;
fields[2].type = ira->codegen->builtin_types.entry_u8;
bigint_init_unsigned(&fields[2].data.x_bigint, mantissa_bits);

break;
}
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14 changes: 14 additions & 0 deletions test/cases/type_info.zig
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Expand Up @@ -26,9 +26,23 @@ fn testIntFloat() void {
assert(!u8_info.Int.is_signed);
assert(u8_info.Int.bits == 8);

const f32_info = @typeInfo(f32);
assert(TypeId(f32_info) == TypeId.Float);
assert(f32_info.Float.bits == 32);
assert(f32_info.Float.exponent_bits == 8);
assert(f32_info.Float.mantissa_bits == 23);

const f64_info = @typeInfo(f64);
assert(TypeId(f64_info) == TypeId.Float);
assert(f64_info.Float.bits == 64);
assert(f64_info.Float.exponent_bits == 11);
assert(f64_info.Float.mantissa_bits == 52);

const f128_info = @typeInfo(f128);
assert(TypeId(f128_info) == TypeId.Float);
assert(f128_info.Float.bits == 128);
assert(f128_info.Float.exponent_bits == 15);
assert(f128_info.Float.mantissa_bits == 112);
}

test "type info: pointer type info" {
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