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stage2: further cleanups regarding zir.Inst.Ref

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* Introduce helper functions on Module.WipZirCode and zir.Code
 * Move some logic around
 * re-introduce ref_start_index
 * prefer usize for local variables + `@intCast` at the end.
   Empirically this is easier to optimize.
 * Avoid using mem.{bytesAsSlice,sliceAsBytes} because it incurs an
   unnecessary multiplication/division which may cause problems for the
   optimizer.
 * Use a regular enum, not packed, for `Ref`. Memory layout is
   guaranteed for enums which specify their tag type. Packed enums have
   ABI alignment of 1 byte which is too small.
This commit is contained in:
Andrew Kelley
2021-03-24 15:24:18 -07:00
parent 0c601965ab
commit 180dae4196
5 changed files with 95 additions and 94 deletions
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65
src/Module.zig
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@@ -1013,7 +1013,7 @@ pub const Scope = struct {
.cc = args.cc,
.param_types_len = @intCast(u32, args.param_types.len),
});
gz.zir_code.extra.appendSliceAssumeCapacity(mem.bytesAsSlice(u32, mem.sliceAsBytes(args.param_types)));
gz.zir_code.appendRefsAssumeCapacity(args.param_types);
const new_index = @intCast(zir.Inst.Index, gz.zir_code.instructions.len);
gz.zir_code.instructions.appendAssumeCapacity(.{
@@ -1024,7 +1024,7 @@ pub const Scope = struct {
} },
});
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
pub fn addFnType(
@@ -1043,7 +1043,7 @@ pub const Scope = struct {
const payload_index = gz.zir_code.addExtraAssumeCapacity(zir.Inst.FnType{
.param_types_len = @intCast(u32, param_types.len),
});
gz.zir_code.extra.appendSliceAssumeCapacity(mem.bytesAsSlice(u32, mem.sliceAsBytes(param_types)));
gz.zir_code.appendRefsAssumeCapacity(param_types);
const new_index = @intCast(zir.Inst.Index, gz.zir_code.instructions.len);
gz.zir_code.instructions.appendAssumeCapacity(.{
@@ -1054,7 +1054,7 @@ pub const Scope = struct {
} },
});
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
pub fn addCall(
@@ -1077,7 +1077,7 @@ pub const Scope = struct {
.callee = callee,
.args_len = @intCast(u32, args.len),
});
gz.zir_code.extra.appendSliceAssumeCapacity(mem.bytesAsSlice(u32, mem.sliceAsBytes(args)));
gz.zir_code.appendRefsAssumeCapacity(args);
const new_index = @intCast(zir.Inst.Index, gz.zir_code.instructions.len);
gz.zir_code.instructions.appendAssumeCapacity(.{
@@ -1088,7 +1088,7 @@ pub const Scope = struct {
} },
});
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
/// Note that this returns a `zir.Inst.Index` not a ref.
@@ -1160,7 +1160,7 @@ pub const Scope = struct {
} },
});
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
pub fn addArrayTypeSentinel(
@@ -1186,7 +1186,7 @@ pub const Scope = struct {
} },
});
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
pub fn addUnTok(
@@ -1317,7 +1317,7 @@ pub const Scope = struct {
const new_index = @intCast(zir.Inst.Index, gz.zir_code.instructions.len);
gz.zir_code.instructions.appendAssumeCapacity(inst);
gz.instructions.appendAssumeCapacity(new_index);
return zir.Inst.Ref.fromIndex(new_index, gz.zir_code.param_count);
return gz.zir_code.indexToRef(new_index);
}
};
@@ -1366,9 +1366,9 @@ pub const WipZirCode = struct {
instructions: std.MultiArrayList(zir.Inst) = .{},
string_bytes: std.ArrayListUnmanaged(u8) = .{},
extra: std.ArrayListUnmanaged(u32) = .{},
/// We need to keep track of this count in order to convert between
/// `zir.Inst.Ref` and `zir.Inst.Index` types.
param_count: u32 = 0,
/// The end of special indexes. `zir.Inst.Ref` subtracts against this number to convert
/// to `zir.Inst.Index`. The default here is correct if there are 0 parameters.
ref_start_index: u32 = zir.Inst.Ref.typed_value_map.len,
decl: *Decl,
gpa: *Allocator,
arena: *Allocator,
@@ -1386,20 +1386,43 @@ pub const WipZirCode = struct {
wzc.extra.appendAssumeCapacity(switch (field.field_type) {
u32 => @field(extra, field.name),
zir.Inst.Ref => @enumToInt(@field(extra, field.name)),
else => unreachable,
else => @compileError("bad field type"),
});
}
return result;
}
pub fn refIsNoReturn(wzc: WipZirCode, zir_inst_ref: zir.Inst.Ref) bool {
if (zir_inst_ref == .unreachable_value) return true;
if (zir_inst_ref.toIndex(wzc.param_count)) |zir_inst| {
return wzc.instructions.items(.tag)[zir_inst].isNoReturn();
pub fn appendRefs(wzc: *WipZirCode, refs: []const zir.Inst.Ref) !void {
const coerced = @bitCast([]const u32, refs);
return wzc.extra.appendSlice(wzc.gpa, coerced);
}
pub fn appendRefsAssumeCapacity(wzc: *WipZirCode, refs: []const zir.Inst.Ref) void {
const coerced = @bitCast([]const u32, refs);
wzc.extra.appendSliceAssumeCapacity(coerced);
}
pub fn refIsNoReturn(wzc: WipZirCode, inst_ref: zir.Inst.Ref) bool {
if (inst_ref == .unreachable_value) return true;
if (wzc.refToIndex(inst_ref)) |inst_index| {
return wzc.instructions.items(.tag)[inst_index].isNoReturn();
}
return false;
}
pub fn indexToRef(wzc: WipZirCode, inst: zir.Inst.Index) zir.Inst.Ref {
return @intToEnum(zir.Inst.Ref, wzc.ref_start_index + inst);
}
pub fn refToIndex(wzc: WipZirCode, inst: zir.Inst.Ref) ?zir.Inst.Index {
const ref_int = @enumToInt(inst);
if (ref_int >= wzc.ref_start_index) {
return ref_int - wzc.ref_start_index;
} else {
return null;
}
}
pub fn deinit(wzc: *WipZirCode) void {
wzc.instructions.deinit(wzc.gpa);
wzc.extra.deinit(wzc.gpa);
@@ -2075,7 +2098,7 @@ fn astgenAndSemaFn(
// The AST params array does not contain anytype and ... parameters.
// We must iterate to count how many param types to allocate.
const param_count = blk: {
var count: u32 = 0;
var count: usize = 0;
var it = fn_proto.iterate(tree);
while (it.next()) |param| {
if (param.anytype_ellipsis3) |some| if (token_tags[some] == .ellipsis3) break;
@@ -2297,7 +2320,7 @@ fn astgenAndSemaFn(
.decl = decl,
.arena = &decl_arena.allocator,
.gpa = mod.gpa,
.param_count = param_count,
.ref_start_index = @intCast(u32, zir.Inst.Ref.typed_value_map.len + param_count),
};
defer wip_zir_code.deinit();
@@ -2314,7 +2337,7 @@ fn astgenAndSemaFn(
try wip_zir_code.extra.ensureCapacity(mod.gpa, param_count);
var params_scope = &gen_scope.base;
var i: u32 = 0;
var i: usize = 0;
var it = fn_proto.iterate(tree);
while (it.next()) |param| : (i += 1) {
const name_token = param.name_token.?;
@@ -2325,7 +2348,7 @@ fn astgenAndSemaFn(
.gen_zir = &gen_scope,
.name = param_name,
// Implicit const list first, then implicit arg list.
.inst = zir.Inst.Ref.fromParam(i),
.inst = @intToEnum(zir.Inst.Ref, @intCast(u32, zir.Inst.Ref.typed_value_map.len + i)),
.src = decl.tokSrcLoc(name_token),
};
params_scope = &sub_scope.base;