diff options
| author | Cody Tapscott <topolarity@tapscott.me> | 2022-03-22 23:32:57 -0700 |
|---|---|---|
| committer | Andrew Kelley <andrew@ziglang.org> | 2022-03-23 13:44:31 -0700 |
| commit | 5374e245c50fde8bbb133bbff2db15efa3604721 (patch) | |
| tree | f97abf82092e557f0e73a119fe7ac36506b9e8f4 /src/Sema.zig | |
| parent | 1c223819098e5621e2e5ad526879cd33852144e1 (diff) | |
| download | zig-5374e245c50fde8bbb133bbff2db15efa3604721.tar.gz zig-5374e245c50fde8bbb133bbff2db15efa3604721.zip | |
stage2: Remove premature elem_val index check
We were enforcing bounds on the index of an elem_ptr in pointerDeref,
but we want to support out-of-bounds accesses by reinterpreting memory.
This removes that check, so that the deref falls back to bitcasting, as
usual.
This was masked by another bug that was forcing bitcasts incorrectly,
which is why this wasn't noticed earlier.
Diffstat (limited to 'src/Sema.zig')
| -rw-r--r-- | src/Sema.zig | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/src/Sema.zig b/src/Sema.zig index 7b5296dd78..fe10810d57 100644 --- a/src/Sema.zig +++ b/src/Sema.zig @@ -18752,6 +18752,11 @@ fn beginComptimePtrLoad( const elem_ty = elem_ptr.elem_ty; var deref = try beginComptimePtrLoad(sema, block, src, elem_ptr.array_ptr, null); + // This code assumes that elem_ptrs have been "flattened" in order for direct dereference + // to succeed, meaning that elem ptrs of the same elem_ty are coalesced. Here we check that + // our parent is not an elem_ptr with the same elem_ty, since that would be "unflattened" + if (elem_ptr.array_ptr.castTag(.elem_ptr)) |parent_elem_ptr| assert(!(parent_elem_ptr.data.elem_ty.eql(elem_ty, target))); + if (elem_ptr.index != 0) { if (elem_ty.hasWellDefinedLayout()) { if (deref.parent) |*parent| { @@ -18780,13 +18785,6 @@ fn beginComptimePtrLoad( var array_tv = deref.pointee.?; const check_len = array_tv.ty.arrayLenIncludingSentinel(); - if (elem_ptr.index >= check_len) { - // TODO have the deref include the decl so we can say "declared here" - return sema.fail(block, src, "comptime load of index {d} out of bounds of array length {d}", .{ - elem_ptr.index, check_len, - }); - } - if (maybe_array_ty) |load_ty| { // It's possible that we're loading a [N]T, in which case we'd like to slice // the pointee array directly from our parent array. @@ -18800,10 +18798,10 @@ fn beginComptimePtrLoad( } } - deref.pointee = .{ + deref.pointee = if (elem_ptr.index < check_len) TypedValue{ .ty = elem_ty, .val = try array_tv.val.elemValue(sema.arena, elem_ptr.index), - }; + } else null; break :blk deref; }, |