mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-02-21 16:54:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

Sema: elide comptime-checked slice safety

Browse Source 
Before, Zig would emit a start<=end safety check for `foo[1..2]` even
though it was already checked at compile-time.
This commit is contained in:
Andrew Kelley 2023-05-31 13:38:25 -07:00
parent b2391a7d44
commit 870e3843c5
1 changed files with 20 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
src/Sema.zig
View File

@ -24146,20 +24146,6 @@ fn panicIndexOutOfBounds(
try sema.safetyCheckFormatted(parent_block, ok, "panicOutOfBounds", &.{ index, len });
}
fn panicStartGreaterThanEnd(
sema: *Sema,
parent_block: *Block,
start: Air.Inst.Ref,
end: Air.Inst.Ref,
) !void {
assert(!parent_block.is_comptime);
const ok = try parent_block.addBinOp(.cmp_lte, start, end);
if (!sema.mod.comp.formatted_panics) {
return sema.addSafetyCheck(parent_block, ok, .start_index_greater_than_end);
}
try sema.safetyCheckFormatted(parent_block, ok, "panicStartGreaterThanEnd", &.{ start, end });
}
fn panicInactiveUnionField(
sema: *Sema,
parent_block: *Block,
@ -30209,11 +30195,12 @@ fn analyzeSlice(
};
const slice_sentinel = if (sentinel_opt != .none) sentinel else null;
var checked_start_lte_end = by_length;
var runtime_src: ?LazySrcLoc = null;
// requirement: start <= end
var need_start_gt_end_check = true;
if (try sema.resolveDefinedValue(block, end_src, end)) |end_val| {
if (try sema.resolveDefinedValue(block, start_src, start)) |start_val| {
need_start_gt_end_check = false;
if (!by_length and !(try sema.compareAll(start_val, .lte, end_val, Type.usize))) {
return sema.fail(
block,
@ -30225,6 +30212,7 @@ fn analyzeSlice(
},
);
}
checked_start_lte_end = true;
if (try sema.resolveMaybeUndefVal(new_ptr)) |ptr_val| sentinel_check: {
const expected_sentinel = sentinel orelse break :sentinel_check;
const start_int = start_val.getUnsignedInt(mod).?;
@ -30266,13 +30254,26 @@ fn analyzeSlice(
};
return sema.failWithOwnedErrorMsg(msg);
}
} else {
runtime_src = ptr_src;
}
} else {
runtime_src = start_src;
}
} else {
runtime_src = end_src;
}
if (!by_length and block.wantSafety() and !block.is_comptime and need_start_gt_end_check) {
if (!checked_start_lte_end and block.wantSafety() and !block.is_comptime) {
// requirement: start <= end
try sema.panicStartGreaterThanEnd(block, start, end);
assert(!block.is_comptime);
try sema.requireRuntimeBlock(block, src, runtime_src.?);
const ok = try block.addBinOp(.cmp_lte, start, end);
if (!sema.mod.comp.formatted_panics) {
try sema.addSafetyCheck(block, ok, .start_index_greater_than_end);
} else {
try sema.safetyCheckFormatted(block, ok, "panicStartGreaterThanEnd", &.{ start, end });
}
}
const new_len = if (by_length)
try sema.coerce(block, Type.usize, uncasted_end_opt, end_src)
@ -30354,14 +30355,7 @@ fn analyzeSlice(
.size = .Slice,
});
const runtime_src = if ((try sema.resolveMaybeUndefVal(ptr_or_slice)) == null)
ptr_src
else if ((try sema.resolveMaybeUndefVal(start)) == null)
start_src
else
end_src;
try sema.requireRuntimeBlock(block, src, runtime_src);
try sema.requireRuntimeBlock(block, src, runtime_src.?);
if (block.wantSafety()) {
// requirement: slicing C ptr is non-null
if (ptr_ptr_child_ty.isCPtr(mod)) {