Use different limits for items in components (#1390)

Right now the validation limit for the number of memories or tables in a
component is quite small, only 100. This is the core wasm limit which is
intended to limit the number of definitions in core wasm, but in a
component items taking up the index space are just references, not
definitions. That means they don't need to have similarly small limits
and can instead be much larger.

Closes #1389

Author: alexcrichton

crates/wasm-compose/tests/compositions/not-instance-import/composed.wat

@@ -18,4 +18,4 @@
       (with "a" (func 0))
     )
   )
-)
+)

crates/wasmparser/src/limits.rs

@@ -57,3 +57,8 @@ pub const MAX_WASM_MODULES: usize = 1_000;
 pub const MAX_WASM_COMPONENTS: usize = 1_000;
 pub const MAX_WASM_INSTANCES: usize = 1_000;
 pub const MAX_WASM_VALUES: usize = 1_000;
+
+/// Core items in components such as globals/memories/tables don't actually
+/// create new definitions but are instead just aliases to preexisting items.
+/// This means they have a different limit than the core wasm based limits.
+pub const MAX_CORE_INDEX_SPACE_ITEMS: usize = 1_000_000;

crates/wasmparser/src/validator/component.rs

@@ -2303,14 +2303,20 @@ impl ComponentState {
                 push_module_export!(EntityType::Func, core_funcs, "function")
             }
             ExternalKind::Table => {
-                check_max(self.core_tables.len(), 1, MAX_WASM_TABLES, "tables", offset)?;
+                check_max(
+                    self.core_tables.len(),
+                    1,
+                    MAX_CORE_INDEX_SPACE_ITEMS,
+                    "tables",
+                    offset,
+                )?;
                 push_module_export!(EntityType::Table, core_tables, "table")
             }
             ExternalKind::Memory => {
                 check_max(
                     self.core_memories.len(),
                     1,
-                    MAX_WASM_MEMORIES,
+                    MAX_CORE_INDEX_SPACE_ITEMS,
                     "memories",
                     offset,
                 )?;
@@ -2320,14 +2326,20 @@ impl ComponentState {
                 check_max(
                     self.core_globals.len(),
                     1,
-                    MAX_WASM_GLOBALS,
+                    MAX_CORE_INDEX_SPACE_ITEMS,
                     "globals",
                     offset,
                 )?;
                 push_module_export!(EntityType::Global, core_globals, "global")
             }
             ExternalKind::Tag => {
-                check_max(self.core_tags.len(), 1, MAX_WASM_TAGS, "tags", offset)?;
+                check_max(
+                    self.core_tags.len(),
+                    1,
+                    MAX_CORE_INDEX_SPACE_ITEMS,
+                    "tags",
+                    offset,
+                )?;
                 push_module_export!(EntityType::Tag, core_tags, "tag")
             }
         }