fix bug in use of alignment in free for tag unions

roc-lang · Sep 28, 2023 · 35e56c3 · 35e56c3
1 parent b6218a1
commit 35e56c3
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Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/crates/compiler/builtins/bitcode/src/utils.zig b/crates/compiler/builtins/bitcode/src/utils.zig
@@ -267,8 +267,9 @@ pub fn freeDataPtrC(
     const masked_ptr = ptr & ~tag_mask;
 
     const isizes: [*]isize = @as([*]isize, @ptrFromInt(masked_ptr));
+    const offset = @max(1, @divFloor(alignment, @sizeOf(usize)));
 
-    return freeRcPtrC(isizes - 1, alignment);
+    return freeRcPtrC(isizes - offset, alignment);
 }
 
 pub fn freeRcPtrC(

diff --git a/crates/compiler/gen_llvm/src/llvm/build.rs b/crates/compiler/gen_llvm/src/llvm/build.rs
@@ -3465,7 +3465,7 @@ pub(crate) fn build_exp_stmt<'a, 'ctx>(
                 Free(symbol) => {
                     // unconditionally deallocate the symbol
                     let (value, layout) = scope.load_symbol_and_layout(symbol);
-                    let alignment = layout_interner.alignment_bytes(layout);
+                    let alignment = layout_interner.allocation_alignment_bytes(layout);
 
                     debug_assert!(value.is_pointer_value());
                     let value = value.into_pointer_value();