Limit component model flags to 32 (#1635)

* Limit component model flags to 32 This commit is an attempt to explore the design space of WebAssembly/component-model#370. This limits, by default, the number of flags in a component model type to 32 by default. The hope of this issue is to be able to ratchet the maximum number of flags to make it easier on bindings generators to not need to work with arbitrary numbers of flags. The secondary hope is that we can ratchet flags straight to 32 instead of 64 due to it being unlikely that more than 32 flags are in use. Once this percolates there can then be a separate feature for enabling 33-64 flags. * Drop a link
bytecodealliance · Jun 25, 2024 · 2c6f127 · 2c6f127
1 parent 659f4a6
commit 2c6f127
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Showing 9 changed files with 130 additions and 174 deletions.
diff --git a/crates/wasmparser/src/features.rs b/crates/wasmparser/src/features.rs
@@ -146,6 +146,8 @@ define_wasm_features! {
  pub component_model_values: COMPONENT_MODEL_VALUES(1 << 21) = false;
  /// Support for the nested namespaces and projects in component model names.
  pub component_model_nested_names: COMPONENT_MODEL_NESTED_NAMES(1 << 22) = false;
+ /// Support for more than 32 flags per-type in the component model.
+ pub component_model_more_flags: COMPONENT_MODEL_MORE_FLAGS(1 << 23) = false;
  }
 }
 

diff --git a/crates/wasmparser/src/validator/component.rs b/crates/wasmparser/src/validator/component.rs
@@ -348,7 +348,7 @@ impl ComponentState {
 
  let id = match ty {
  crate::ComponentType::Defined(ty) => {
- let ty = current(components).create_defined_type(ty, types, offset)?;
+ let ty = current(components).create_defined_type(ty, types, features, offset)?;
  types.push(ty).into()
  }
  crate::ComponentType::Func(ty) => {
@@ -2512,6 +2512,7 @@ impl ComponentState {
  &self,
  ty: crate::ComponentDefinedType,
  types: &TypeList,
+ features: &WasmFeatures,
  offset: usize,
  ) -> Result<ComponentDefinedType> {
  match ty {
@@ -2529,7 +2530,7 @@ impl ComponentState {
  self.create_tuple_type(tys.as_ref(), types, offset)
  }
  crate::ComponentDefinedType::Flags(names) => {
- self.create_flags_type(names.as_ref(), offset)
+ self.create_flags_type(names.as_ref(), features, offset)
  }
  crate::ComponentDefinedType::Enum(cases) => {
  self.create_enum_type(cases.as_ref(), offset)
@@ -2681,14 +2682,29 @@ impl ComponentState {
  Ok(ComponentDefinedType::Tuple(TupleType { info, types }))
  }
 
- fn create_flags_type(&self, names: &[&str], offset: usize) -> Result<ComponentDefinedType> {
+ fn create_flags_type(
+ &self,
+ names: &[&str],
+ features: &WasmFeatures,
+ offset: usize,
+ ) -> Result<ComponentDefinedType> {
  let mut names_set = IndexSet::default();
  names_set.reserve(names.len());
 
  if names.is_empty() {
  bail!(offset, "flags must have at least one entry");
  }
 
+ if names.len() > 32 && !features.component_model_more_flags() {
+ bail!(
+ offset,
+ "cannot have more than 32 flags; this was previously \
+ accepted and if this is required for your project please \
+ leave a comment on \
+ https://github.com/WebAssembly/component-model/issues/370"
+ );
+ }
+
  for name in names {
  let name = to_kebab_str(name, "flag", offset)?;
  if !names_set.insert(name.to_owned()) {

diff --git a/crates/wit-component/tests/interfaces/flags.wat b/crates/wit-component/tests/interfaces/flags.wat
@@ -15,22 +15,18 @@
  (export (;9;) "flag16" (type (eq 8)))
  (type (;10;) (flags "b0" "b1" "b2" "b3" "b4" "b5" "b6" "b7" "b8" "b9" "b10" "b11" "b12" "b13" "b14" "b15" "b16" "b17" "b18" "b19" "b20" "b21" "b22" "b23" "b24" "b25" "b26" "b27" "b28" "b29" "b30" "b31"))
  (export (;11;) "flag32" (type (eq 10)))
- (type (;12;) (flags "b0" "b1" "b2" "b3" "b4" "b5" "b6" "b7" "b8" "b9" "b10" "b11" "b12" "b13" "b14" "b15" "b16" "b17" "b18" "b19" "b20" "b21" "b22" "b23" "b24" "b25" "b26" "b27" "b28" "b29" "b30" "b31" "b32" "b33" "b34" "b35" "b36" "b37" "b38" "b39" "b40" "b41" "b42" "b43" "b44" "b45" "b46" "b47" "b48" "b49" "b50" "b51" "b52" "b53" "b54" "b55" "b56" "b57" "b58" "b59" "b60" "b61" "b62" "b63"))
- (export (;13;) "flag64" (type (eq 12)))
- (type (;14;) (func (param "x" 1) (result 1)))
- (export (;0;) "roundtrip-flag1" (func (type 14)))
- (type (;15;) (func (param "x" 3) (result 3)))
- (export (;1;) "roundtrip-flag2" (func (type 15)))
- (type (;16;) (func (param "x" 5) (result 5)))
- (export (;2;) "roundtrip-flag4" (func (type 16)))
- (type (;17;) (func (param "x" 7) (result 7)))
- (export (;3;) "roundtrip-flag8" (func (type 17)))
- (type (;18;) (func (param "x" 9) (result 9)))
- (export (;4;) "roundtrip-flag16" (func (type 18)))
- (type (;19;) (func (param "x" 11) (result 11)))
- (export (;5;) "roundtrip-flag32" (func (type 19)))
- (type (;20;) (func (param "x" 13) (result 13)))
- (export (;6;) "roundtrip-flag64" (func (type 20)))
+ (type (;12;) (func (param "x" 1) (result 1)))
+ (export (;0;) "roundtrip-flag1" (func (type 12)))
+ (type (;13;) (func (param "x" 3) (result 3)))
+ (export (;1;) "roundtrip-flag2" (func (type 13)))
+ (type (;14;) (func (param "x" 5) (result 5)))
+ (export (;2;) "roundtrip-flag4" (func (type 14)))
+ (type (;15;) (func (param "x" 7) (result 7)))
+ (export (;3;) "roundtrip-flag8" (func (type 15)))
+ (type (;16;) (func (param "x" 9) (result 9)))
+ (export (;4;) "roundtrip-flag16" (func (type 16)))
+ (type (;17;) (func (param "x" 11) (result 11)))
+ (export (;5;) "roundtrip-flag32" (func (type 17)))
  )
  )
  (export (;0;) "foo:flags/imports" (instance (type 0)))
@@ -55,22 +51,18 @@
  (export (;9;) "flag16" (type (eq 8)))
  (type (;10;) (flags "b0" "b1" "b2" "b3" "b4" "b5" "b6" "b7" "b8" "b9" "b10" "b11" "b12" "b13" "b14" "b15" "b16" "b17" "b18" "b19" "b20" "b21" "b22" "b23" "b24" "b25" "b26" "b27" "b28" "b29" "b30" "b31"))
  (export (;11;) "flag32" (type (eq 10)))
- (type (;12;) (flags "b0" "b1" "b2" "b3" "b4" "b5" "b6" "b7" "b8" "b9" "b10" "b11" "b12" "b13" "b14" "b15" "b16" "b17" "b18" "b19" "b20" "b21" "b22" "b23" "b24" "b25" "b26" "b27" "b28" "b29" "b30" "b31" "b32" "b33" "b34" "b35" "b36" "b37" "b38" "b39" "b40" "b41" "b42" "b43" "b44" "b45" "b46" "b47" "b48" "b49" "b50" "b51" "b52" "b53" "b54" "b55" "b56" "b57" "b58" "b59" "b60" "b61" "b62" "b63"))
- (export (;13;) "flag64" (type (eq 12)))
- (type (;14;) (func (param "x" 1) (result 1)))
- (export (;0;) "roundtrip-flag1" (func (type 14)))
- (type (;15;) (func (param "x" 3) (result 3)))
- (export (;1;) "roundtrip-flag2" (func (type 15)))
- (type (;16;) (func (param "x" 5) (result 5)))
- (export (;2;) "roundtrip-flag4" (func (type 16)))
- (type (;17;) (func (param "x" 7) (result 7)))
- (export (;3;) "roundtrip-flag8" (func (type 17)))
- (type (;18;) (func (param "x" 9) (result 9)))
- (export (;4;) "roundtrip-flag16" (func (type 18)))
- (type (;19;) (func (param "x" 11) (result 11)))
- (export (;5;) "roundtrip-flag32" (func (type 19)))
- (type (;20;) (func (param "x" 13) (result 13)))
- (export (;6;) "roundtrip-flag64" (func (type 20)))
+ (type (;12;) (func (param "x" 1) (result 1)))
+ (export (;0;) "roundtrip-flag1" (func (type 12)))
+ (type (;13;) (func (param "x" 3) (result 3)))
+ (export (;1;) "roundtrip-flag2" (func (type 13)))
+ (type (;14;) (func (param "x" 5) (result 5)))
+ (export (;2;) "roundtrip-flag4" (func (type 14)))
+ (type (;15;) (func (param "x" 7) (result 7)))
+ (export (;3;) "roundtrip-flag8" (func (type 15)))
+ (type (;16;) (func (param "x" 9) (result 9)))
+ (export (;4;) "roundtrip-flag16" (func (type 16)))
+ (type (;17;) (func (param "x" 11) (result 11)))
+ (export (;5;) "roundtrip-flag32" (func (type 17)))
  )
  )
  (import "foo:flags/imports" (instance (;0;) (type 0)))

diff --git a/crates/wit-component/tests/interfaces/flags.wit b/crates/wit-component/tests/interfaces/flags.wit
@@ -82,73 +82,6 @@ interface imports {
  b31,
  }
 
- flags flag64 {
- b0,
- b1,
- b2,
- b3,
- b4,
- b5,
- b6,
- b7,
- b8,
- b9,
- b10,
- b11,
- b12,
- b13,
- b14,
- b15,
- b16,
- b17,
- b18,
- b19,
- b20,
- b21,
- b22,
- b23,
- b24,
- b25,
- b26,
- b27,
- b28,
- b29,
- b30,
- b31,
- b32,
- b33,
- b34,
- b35,
- b36,
- b37,
- b38,
- b39,
- b40,
- b41,
- b42,
- b43,
- b44,
- b45,
- b46,
- b47,
- b48,
- b49,
- b50,
- b51,
- b52,
- b53,
- b54,
- b55,
- b56,
- b57,
- b58,
- b59,
- b60,
- b61,
- b62,
- b63,
- }
-
  roundtrip-flag1: func(x: flag1) -> flag1;
 
  roundtrip-flag2: func(x: flag2) -> flag2;
@@ -160,8 +93,6 @@ interface imports {
  roundtrip-flag16: func(x: flag16) -> flag16;
 
  roundtrip-flag32: func(x: flag32) -> flag32;
-
- roundtrip-flag64: func(x: flag64) -> flag64;
 }
 
 world flags-world {

diff --git a/crates/wit-component/tests/interfaces/flags.wit.print b/crates/wit-component/tests/interfaces/flags.wit.print
@@ -82,73 +82,6 @@ interface imports {
  b31,
  }
 
- flags flag64 {
- b0,
- b1,
- b2,
- b3,
- b4,
- b5,
- b6,
- b7,
- b8,
- b9,
- b10,
- b11,
- b12,
- b13,
- b14,
- b15,
- b16,
- b17,
- b18,
- b19,
- b20,
- b21,
- b22,
- b23,
- b24,
- b25,
- b26,
- b27,
- b28,
- b29,
- b30,
- b31,
- b32,
- b33,
- b34,
- b35,
- b36,
- b37,
- b38,
- b39,
- b40,
- b41,
- b42,
- b43,
- b44,
- b45,
- b46,
- b47,
- b48,
- b49,
- b50,
- b51,
- b52,
- b53,
- b54,
- b55,
- b56,
- b57,
- b58,
- b59,
- b60,
- b61,
- b62,
- b63,
- }
-
  roundtrip-flag1: func(x: flag1) -> flag1;
 
  roundtrip-flag2: func(x: flag2) -> flag2;
@@ -160,8 +93,6 @@ interface imports {
  roundtrip-flag16: func(x: flag16) -> flag16;
 
  roundtrip-flag32: func(x: flag32) -> flag32;
-
- roundtrip-flag64: func(x: flag64) -> flag64;
 }
 
 world flags-world {

diff --git a/tests/local/component-model/more-flags.wast b/tests/local/component-model/more-flags.wast
@@ -0,0 +1,37 @@
+(component
+ (type (flags
+ "f1"
+ "f2"
+ "f3"
+ "f4"
+ "f5"
+ "f6"
+ "f7"
+ "f8"
+ "f9"
+ "f10"
+ "f11"
+ "f12"
+ "f13"
+ "f14"
+ "f15"
+ "f16"
+ "f17"
+ "f18"
+ "f19"
+ "f20"
+ "f21"
+ "f22"
+ "f23"
+ "f24"
+ "f25"
+ "f26"
+ "f27"
+ "f28"
+ "f29"
+ "f30"
+ "f31"
+ "f32"
+ "f33"
+ ))
+)
diff --git a/tests/local/component-model/types.wast b/tests/local/component-model/types.wast
@@ -323,3 +323,43 @@
  ))
  )
 )
+
+(assert_invalid
+ (component
+ (type (flags
+ "f1"
+ "f2"
+ "f3"
+ "f4"
+ "f5"
+ "f6"
+ "f7"
+ "f8"
+ "f9"
+ "f10"
+ "f11"
+ "f12"
+ "f13"
+ "f14"
+ "f15"
+ "f16"
+ "f17"
+ "f18"
+ "f19"
+ "f20"
+ "f21"
+ "f22"
+ "f23"
+ "f24"
+ "f25"
+ "f26"
+ "f27"
+ "f28"
+ "f29"
+ "f30"
+ "f31"
+ "f32"
+ "f33"
+ ))
+ )
+ "cannot have more than 32 flags")