motiejus/zig
1
Fork 0
Code Releases Activity

stage2: improve orelse implementation

Browse Source 
* Now it supports being an lvalue (see additional lines in the test
   case).
 * Properly handles a pointer result location (see additional lines in
   the test case that assign the result of the orelse to a variable
   rather than a const).
 * Properly sets the result location type when possible, so that type
   inference of an `orelse` operand expression knows its result type.
This commit is contained in:
Andrew Kelley
2021-03-02 21:59:23 -07:00
parent 6aa1ea9c59
commit 713f113822
4 changed files with 55 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/astgen.zig
View File

@@ -1709,14 +1709,13 @@ fn orelseCatchExpr(
setBlockResultLoc(&block_scope, rl);
defer block_scope.instructions.deinit(mod.gpa);
// This could be a pointer or value depending on the `rl` parameter.
// This could be a pointer or value depending on the `operand_rl` parameter.
// We cannot use `block_scope.break_result_loc` because that has the bare
// type, whereas this expression has the optional type. Later we make
// up for this fact by calling rvalue on the else branch.
block_scope.break_count += 1;
const operand = try expr(
mod,
&block_scope.base,
if (block_scope.break_result_loc == .ref) .ref else .none,
lhs,
);
const operand_rl = try makeOptionalTypeResultLoc(mod, &block_scope.base, src, block_scope.break_result_loc);
const operand = try expr(mod, &block_scope.base, operand_rl, lhs);
const cond = try addZIRUnOp(mod, &block_scope.base, src, cond_op, operand);
const condbr = try addZIRInstSpecial(mod, &block_scope.base, src, zir.Inst.CondBr, .{
@@ -1768,6 +1767,10 @@ fn orelseCatchExpr(
// This could be a pointer or value depending on `unwrap_op`.
const unwrapped_payload = try addZIRUnOp(mod, &else_scope.base, src, unwrap_op, operand);
const else_result = switch (rl) {
.ref => unwrapped_payload,
else => try rvalue(mod, &else_scope.base, block_scope.break_result_loc, unwrapped_payload),
};
return finishThenElseBlock(
mod,
@@ -1781,7 +1784,7 @@ fn orelseCatchExpr(
src,
src,
then_result,
unwrapped_payload,
else_result,
block,
block,
);
@@ -3970,6 +3973,25 @@ fn rlStrategy(rl: ResultLoc, block_scope: *Scope.GenZIR) ResultLoc.Strategy {
}
}
/// If the input ResultLoc is ref, returns ResultLoc.ref. Otherwise:
/// Returns ResultLoc.ty, where the type is determined by the input
/// ResultLoc type, wrapped in an optional type. If the input ResultLoc
/// has no type, .none is returned.
fn makeOptionalTypeResultLoc(mod: *Module, scope: *Scope, src: usize, rl: ResultLoc) !ResultLoc {
switch (rl) {
.ref => return ResultLoc.ref,
.discard, .none, .block_ptr, .inferred_ptr, .bitcasted_ptr => return ResultLoc.none,
.ty => |elem_ty| {
const wrapped_ty = try addZIRUnOp(mod, scope, src, .optional_type, elem_ty);
return ResultLoc{ .ty = wrapped_ty };
},
.ptr => |ptr_ty| {
const wrapped_ty = try addZIRUnOp(mod, scope, src, .optional_type_from_ptr_elem, ptr_ty);
return ResultLoc{ .ty = wrapped_ty };
},
}
}
fn setBlockResultLoc(block_scope: *Scope.GenZIR, parent_rl: ResultLoc) void {
// Depending on whether the result location is a pointer or value, different
// ZIR needs to be generated. In the former case we rely on storing to the

5
src/zir.zig
View File

@@ -299,6 +299,9 @@ pub const Inst = struct {
xor,
/// Create an optional type '?T'
optional_type,
/// Create an optional type '?T'. The operand is a pointer value. The optional type will
/// be the type of the pointer element, wrapped in an optional.
optional_type_from_ptr_elem,
/// Create a union type.
union_type,
/// ?T => T with safety.
@@ -397,6 +400,7 @@ pub const Inst = struct {
.mut_slice_type,
.const_slice_type,
.optional_type,
.optional_type_from_ptr_elem,
.optional_payload_safe,
.optional_payload_unsafe,
.optional_payload_safe_ptr,
@@ -597,6 +601,7 @@ pub const Inst = struct {
.typeof,
.xor,
.optional_type,
.optional_type_from_ptr_elem,
.optional_payload_safe,
.optional_payload_unsafe,
.optional_payload_safe_ptr,

11
src/zir_sema.zig
View File

@@ -131,6 +131,7 @@ pub fn analyzeInst(mod: *Module, scope: *Scope, old_inst: *zir.Inst) InnerError!
.typeof => return zirTypeof(mod, scope, old_inst.castTag(.typeof).?),
.typeof_peer => return zirTypeofPeer(mod, scope, old_inst.castTag(.typeof_peer).?),
.optional_type => return zirOptionalType(mod, scope, old_inst.castTag(.optional_type).?),
.optional_type_from_ptr_elem => return zirOptionalTypeFromPtrElem(mod, scope, old_inst.castTag(.optional_type_from_ptr_elem).?),
.optional_payload_safe => return zirOptionalPayload(mod, scope, old_inst.castTag(.optional_payload_safe).?, true),
.optional_payload_unsafe => return zirOptionalPayload(mod, scope, old_inst.castTag(.optional_payload_unsafe).?, false),
.optional_payload_safe_ptr => return zirOptionalPayloadPtr(mod, scope, old_inst.castTag(.optional_payload_safe_ptr).?, true),
@@ -1093,6 +1094,16 @@ fn zirOptionalType(mod: *Module, scope: *Scope, optional: *zir.Inst.UnOp) InnerE
return mod.constType(scope, optional.base.src, try mod.optionalType(scope, child_type));
}
fn zirOptionalTypeFromPtrElem(mod: *Module, scope: *Scope, inst: *zir.Inst.UnOp) InnerError!*Inst {
const tracy = trace(@src());
defer tracy.end();
const ptr = try resolveInst(mod, scope, inst.positionals.operand);
const elem_ty = ptr.ty.elemType();
return mod.constType(scope, inst.base.src, try mod.optionalType(scope, elem_ty));
}
fn zirArrayType(mod: *Module, scope: *Scope, array: *zir.Inst.BinOp) InnerError!*Inst {
const tracy = trace(@src());
defer tracy.end();

9
test/stage2/llvm.zig
View File

@@ -157,6 +157,7 @@ pub fn addCases(ctx: *TestContext) !void {
\\ var ptr_val2 = &(null_val orelse value);
\\
\\ const val3 = opt_val orelse 30;
\\ var val3_var = opt_val orelse 30;
\\
\\ assert(val1 == 10);
\\ assert(val1_1 == 10);
@@ -168,6 +169,14 @@ pub fn addCases(ctx: *TestContext) !void {
\\ assert(ptr_val2.* == 20);
\\
\\ assert(val3 == 10);
\\ assert(val3_var == 10);
\\
\\ (null_val orelse val2) = 1234;
\\ assert(val2 == 1234);
\\
\\ (opt_val orelse val2) = 5678;
\\ assert(opt_val.? == 5678);
\\
\\ return 0;
\\}
, "");