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Sema: detect comptime values in zirMakePtrConst

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This commit is contained in:
Veikka Tuominen 2022-06-01 00:08:29 +03:00
parent d09d61be97
commit e49fd39463
1 changed files with 61 additions and 6 deletions
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67
src/Sema.zig
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@ -2711,17 +2711,72 @@ fn zirAllocComptime(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileErr
fn zirMakePtrConst(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
const inst_data = sema.code.instructions.items(.data)[inst].un_node;
const ptr = try sema.resolveInst(inst_data.operand);
const ptr_ty = sema.typeOf(ptr);
var ptr_info = ptr_ty.ptrInfo().data;
const src = inst_data.src();
const alloc = try sema.resolveInst(inst_data.operand);
const alloc_ty = sema.typeOf(alloc);
var ptr_info = alloc_ty.ptrInfo().data;
const elem_ty = ptr_info.pointee_type;
// Detect if all stores to an `.alloc` were comptime known.
ct: {
var search_index: usize = block.instructions.items.len;
const air_tags = sema.air_instructions.items(.tag);
const air_datas = sema.air_instructions.items(.data);
const store_inst = while (true) {
if (search_index == 0) break :ct;
search_index -= 1;
const candidate = block.instructions.items[search_index];
switch (air_tags[candidate]) {
.dbg_stmt => continue,
.store => break candidate,
else => break :ct,
}
} else unreachable; // TODO shouldn't need this
while (true) {
if (search_index == 0) break :ct;
search_index -= 1;
const candidate = block.instructions.items[search_index];
switch (air_tags[candidate]) {
.dbg_stmt => continue,
.alloc => {
if (Air.indexToRef(candidate) != alloc) break :ct;
break;
},
else => break :ct,
}
}
const store_op = air_datas[store_inst].bin_op;
const store_val = (try sema.resolveMaybeUndefVal(block, src, store_op.rhs)) orelse break :ct;
if (store_op.lhs != alloc) break :ct;
// Remove all the unnecessary runtime instructions.
block.instructions.shrinkRetainingCapacity(search_index);
var anon_decl = try block.startAnonDecl(src);
defer anon_decl.deinit();
return sema.analyzeDeclRef(try anon_decl.finish(
try elem_ty.copy(anon_decl.arena()),
try store_val.copy(anon_decl.arena()),
ptr_info.@"align",
));
}
ptr_info.mutable = false;
const const_ptr_ty = try Type.ptr(sema.arena, sema.mod, ptr_info);
if (try sema.resolveMaybeUndefVal(block, inst_data.src(), ptr)) |val| {
// Detect if a comptime value simply needs to have its type changed.
if (try sema.resolveMaybeUndefVal(block, inst_data.src(), alloc)) |val| {
return sema.addConstant(const_ptr_ty, val);
}
try sema.requireRuntimeBlock(block, inst_data.src());
return block.addBitCast(const_ptr_ty, ptr);
try sema.requireRuntimeBlock(block, src);
return block.addBitCast(const_ptr_ty, alloc);
}
fn zirAllocInferredComptime(