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Allow negative values

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This commit is contained in:
Luuk de Gram 2021-07-23 22:31:45 +02:00
parent cb41f0e58d
commit 72149ae7e4
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GPG Key ID: A8CFE58E4DC7D664
1 changed files with 20 additions and 7 deletions
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27
src/codegen/wasm.zig
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@ -1281,15 +1281,15 @@ pub const Context = struct {
var case_i: u32 = 0;
// a map that maps each value with its index and body
var map = std.AutoArrayHashMap(u32, struct {
var map = std.AutoArrayHashMap(i32, struct {
index: u32,
body: []const Air.Inst.Index,
value: Value,
}).init(self.gpa);
defer map.deinit();
var lowest: u32 = 0;
var highest: u32 = 0;
var lowest: i32 = 0;
var highest: i32 = 0;
while (case_i < switch_br.data.cases_len) : (case_i += 1) {
const case = self.air.extraData(Air.SwitchBr.Case, extra_index);
const items = @bitCast([]const Air.Inst.Ref, self.air.extra[case.end..][0..case.data.items_len]);
@ -1298,9 +1298,15 @@ pub const Context = struct {
for (items) |ref| {
const item_val = self.air.value(ref).?;
// safe to truncate the values as we only use them when
// the target's bits is 32 or lower.
const int_val = @truncate(u32, item_val.toUnsignedInt());
const int_val: i32 = blk: {
if (target_ty.intInfo(self.target).signedness == .signed) {
// safe to truncate the values as we only use them when
// the target's bits is 32 or lower.
break :blk @truncate(i32, item_val.toSignedInt());
}
break :blk @intCast(i32, @truncate(u31, item_val.toUnsignedInt()) - 1);
};
if (int_val < lowest) {
lowest = int_val;
}
@ -1333,9 +1339,16 @@ pub const Context = struct {
// to jump to.
try self.startBlock(.block, blocktype, null);
try self.emitWValue(target);
if (lowest < 0) {
// since br_table works using indexes, starting from '0', we must ensure all values
// we put inside, are atleast 0.
try self.code.append(wasm.opcode(.i32_const));
try leb.writeILEB128(self.code.writer(), lowest * -1);
try self.code.append(wasm.opcode(.i32_add));
}
try self.code.append(wasm.opcode(.br_table));
const depth = highest - lowest + @boolToInt(has_else_body);
try leb.writeULEB128(self.code.writer(), depth);
try leb.writeILEB128(self.code.writer(), depth);
while (lowest <= highest) : (lowest += 1) {
const idx = if (map.get(lowest)) |value| blk: {
break :blk value.index;