fix: allow stack to stay ununified when block types are asserted for br,br_table,return

Signed-off-by: Cem Onem <cem.oenem@dlr.de>

Author: cemonem

src/core/reader/types/element.rs

@@ -132,7 +132,8 @@ impl ElemType {
                 //     },
                 // };
 
-                valid_stack.assert_val_types(&[super::ValType::NumType(super::NumType::I32)])?;
+                valid_stack
+                    .assert_val_types(&[super::ValType::NumType(super::NumType::I32)], true)?;
 
                 ElemMode::Active(ActiveElem {
                     table_idx,

src/validation/code.rs

@@ -168,10 +168,11 @@ fn validate_intrablock_jump_and_generate_sidetable_entry(
     label_idx: usize,
     stack: &mut ValidationStack,
     sidetable: &mut Sidetable,
+    unify_to_expected_types: bool,
 ) -> Result<()> {
     let ctrl_stack_len = stack.ctrl_stack.len();
 
-    stack.assert_val_types_of_label_jump_types_on_top(label_idx)?;
+    stack.assert_val_types_of_label_jump_types_on_top(label_idx, unify_to_expected_types)?;
 
     let targeted_ctrl_block_entry = stack
         .ctrl_stack
@@ -228,15 +229,15 @@ fn read_instructions(
                 let label_info = LabelInfo::Block {
                     stps_to_backpatch: Vec::new(),
                 };
-                stack.assert_push_ctrl(label_info, block_ty)?;
+                stack.assert_push_ctrl(label_info, block_ty, true)?;
             }
             LOOP => {
                 let block_ty = BlockType::read(wasm)?.as_func_type(fn_types)?;
                 let label_info = LabelInfo::Loop {
                     ip: wasm.pc,
                     stp: sidetable.len(),
                 };
-                stack.assert_push_ctrl(label_info, block_ty)?;
+                stack.assert_push_ctrl(label_info, block_ty, true)?;
             }
             IF => {
                 let block_ty = BlockType::read(wasm)?.as_func_type(fn_types)?;
@@ -255,10 +256,10 @@ fn read_instructions(
                     stp: stp_here,
                     stps_to_backpatch: Vec::new(),
                 };
-                stack.assert_push_ctrl(label_info, block_ty)?;
+                stack.assert_push_ctrl(label_info, block_ty, true)?;
             }
             ELSE => {
-                let (mut label_info, block_ty) = stack.assert_pop_ctrl()?;
+                let (mut label_info, block_ty) = stack.assert_pop_ctrl(true)?;
                 if let LabelInfo::If {
                     stp,
                     stps_to_backpatch,
@@ -291,23 +292,23 @@ fn read_instructions(
                         stack.push_valtype(*valtype);
                     }
 
-                    stack.assert_push_ctrl(label_info, block_ty)?;
+                    stack.assert_push_ctrl(label_info, block_ty, true)?;
                 } else {
                     return Err(Error::ElseWithoutMatchingIf);
                 }
             }
             BR => {
                 let label_idx = wasm.read_var_u32()? as LabelIdx;
                 validate_intrablock_jump_and_generate_sidetable_entry(
-                    wasm, label_idx, stack, sidetable,
+                    wasm, label_idx, stack, sidetable, false,
                 )?;
                 stack.make_unspecified()?;
             }
             BR_IF => {
                 let label_idx = wasm.read_var_u32()? as LabelIdx;
                 stack.assert_pop_val_type(ValType::NumType(NumType::I32))?;
                 validate_intrablock_jump_and_generate_sidetable_entry(
-                    wasm, label_idx, stack, sidetable,
+                    wasm, label_idx, stack, sidetable, true,
                 )?;
             }
             BR_TABLE => {
@@ -316,7 +317,7 @@ fn read_instructions(
                 stack.assert_pop_val_type(ValType::NumType(NumType::I32))?;
                 for label_idx in &label_vec {
                     validate_intrablock_jump_and_generate_sidetable_entry(
-                        wasm, *label_idx, stack, sidetable,
+                        wasm, *label_idx, stack, sidetable, false,
                     )?;
                 }
 
@@ -325,6 +326,7 @@ fn read_instructions(
                     max_label_idx,
                     stack,
                     sidetable,
+                    false,
                 )?;
 
                 // The label arity of the branches must be explicitly checked against each other further
@@ -354,7 +356,7 @@ fn read_instructions(
                 stack.make_unspecified()?;
             }
             END => {
-                let (label_info, block_ty) = stack.assert_pop_ctrl()?;
+                let (label_info, block_ty) = stack.assert_pop_ctrl(true)?;
                 let stp_here = sidetable.len();
 
                 match label_info {
@@ -408,7 +410,7 @@ fn read_instructions(
             RETURN => {
                 let label_idx = stack.ctrl_stack.len() - 1; // return behaves the same as br <most_outer>
                 validate_intrablock_jump_and_generate_sidetable_entry(
-                    wasm, label_idx, stack, sidetable,
+                    wasm, label_idx, stack, sidetable, false,
                 )?;
                 stack.make_unspecified()?;
             }
@@ -492,7 +494,7 @@ fn read_instructions(
             LOCAL_TEE => {
                 let local_idx = wasm.read_var_u32()? as LocalIdx;
                 let local_ty = locals.get(local_idx).ok_or(Error::InvalidLocalIdx)?;
-                stack.assert_val_types_on_top(&[*local_ty])?;
+                stack.assert_val_types_on_top(&[*local_ty], true)?;
             }
             // global.get [] -> [t]
             GLOBAL_GET => {

src/validation/data.rs

@@ -38,7 +38,7 @@ pub(super) fn validate_data_section(
                     read_constant_expression(wasm, &mut valid_stack, imported_global_types, None)?
                 };
 
-                valid_stack.assert_val_types(&[ValType::NumType(NumType::I32)])?;
+                valid_stack.assert_val_types(&[ValType::NumType(NumType::I32)], true)?;
 
                 let byte_vec = wasm.read_vec(|el| el.read_u8())?;
 
@@ -77,7 +77,7 @@ pub(super) fn validate_data_section(
                     read_constant_expression(wasm, &mut valid_stack, imported_global_types, None)?
                 };
 
-                valid_stack.assert_val_types(&[ValType::NumType(NumType::I32)])?;
+                valid_stack.assert_val_types(&[ValType::NumType(NumType::I32)], true)?;
 
                 let byte_vec = wasm.read_vec(|el| el.read_u8())?;
 

src/validation/globals.rs

@@ -25,7 +25,7 @@ pub(super) fn validate_global_section(
         let stack = &mut ValidationStack::new();
         let init_expr = read_constant_expression(wasm, stack, imported_global_types, None)?;
 
-        stack.assert_val_types(&[ty.ty])?;
+        stack.assert_val_types(&[ty.ty], true)?;
 
         Ok(Global { ty, init_expr })
     })