Seven-Streams commented on code in PR #685:
URL: https://github.com/apache/tvm-ffi/pull/685#discussion_r3652825800
##########
rust/tvm-ffi-macros/src/match_any.rs:
##########
@@ -24,6 +24,11 @@ use syn::{braced, parenthesized, Expr, Pat, Path, Result,
Token};
use crate::utils::get_tvm_ffi_crate;
+// Keep single-arm matches ordered. Release benchmarks of the standard
ObjectRef
+// conversion path show that lookup pays off from two arms when a later arm or
+// the fallback is reached.
+const MIN_LOOKUP_TABLE_ARMS: usize = 2;
Review Comment:
only 2?
##########
rust/tvm-ffi-macros/src/match_any.rs:
##########
@@ -105,41 +110,225 @@ pub fn expand(input: proc_macro::TokenStream) ->
proc_macro::TokenStream {
fn expand_match_any(input: MatchAnyInput) -> TokenStream {
let tvm_ffi = get_tvm_ffi_crate();
+ let scrutinee = input.scrutinee;
+ let fallback = input.fallback;
+ let arms = input.arms;
+ let can_attempt_leaf_lookup = arms.len() >= MIN_LOOKUP_TABLE_ARMS
+ && arms
+ .iter()
+ .all(|arm| arm.guard.is_none() && is_simple_binding(&arm.binding));
+
+ if can_attempt_leaf_lookup {
+ expand_leaf_lookup_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ } else {
+ expand_ordered_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ }
+}
+
+fn expand_ordered_match(
+ tvm_ffi: &TokenStream,
+ scrutinee: &Expr,
+ arms: &[TypedArm],
+ fallback: &Expr,
+) -> TokenStream {
let span = Span::mixed_site();
let source = Ident::new("__tvm_ffi_match_any_source", span);
let converted = Ident::new("__tvm_ffi_match_any_converted", span);
let view = Ident::new("__tvm_ffi_match_any_view", span);
let rejected = Ident::new("__tvm_ffi_match_any_rejected", span);
- let scrutinee = input.scrutinee;
- let fallback = input.fallback;
- let dispatch_fallback = fallback.clone();
- let arms = input.arms;
- let dispatch = arms
- .into_iter()
- .rev()
- .fold(quote!({ #dispatch_fallback }), |next, arm| {
- let matcher = arm.matcher;
- let binding = arm.binding;
- let body = arm.body;
- let matched = if let Some(guard) = arm.guard {
- quote!(::core::result::Result::Ok(#binding) if #guard)
- } else {
- quote!(::core::result::Result::Ok(#binding))
+ let dispatch = expand_ordered_dispatch(arms, fallback, &view, &rejected);
+
+ quote! {
+ {
+ let #source = &(#scrutinee);
+ let #converted: ::core::result::Result<
+ #tvm_ffi::AnyView<'_>,
+ ::core::convert::Infallible,
+ > =
::core::convert::TryInto::<#tvm_ffi::AnyView<'_>>::try_into(#source);
+ let #view = match #converted {
+ ::core::result::Result::Ok(view) => view,
+ ::core::result::Result::Err(error) => match error {},
};
+ if #view.type_index()
+ >= #tvm_ffi::TypeIndex::kTVMFFIStaticObjectBegin as i32
+ {
+ #dispatch
+ } else {
+ #fallback
+ }
+ }
+ }
+}
+
+fn expand_ordered_dispatch(
+ arms: &[TypedArm],
+ fallback: &Expr,
+ view: &Ident,
+ rejected: &Ident,
+) -> TokenStream {
+ arms.iter().rev().fold(quote!({ #fallback }), |next, arm| {
+ let matcher = &arm.matcher;
+ let binding = &arm.binding;
+ let body = &arm.body;
+ let matched = if let Some(guard) = &arm.guard {
+ quote!(::core::result::Result::Ok(#binding) if #guard)
+ } else {
+ quote!(::core::result::Result::Ok(#binding))
+ };
+
+ quote! {
+ match ::core::convert::TryInto::<#matcher>::try_into(#view) {
+ #matched => { #body },
+ #rejected => {
+ ::core::mem::drop(#rejected);
+ #next
+ }
+ }
+ }
+ })
+}
+
+fn expand_leaf_lookup_match(
+ tvm_ffi: &TokenStream,
+ scrutinee: &Expr,
+ arms: &[TypedArm],
+ fallback: &Expr,
+) -> TokenStream {
+ let span = Span::mixed_site();
+ let source = Ident::new("__tvm_ffi_match_any_source", span);
+ let converted = Ident::new("__tvm_ffi_match_any_converted", span);
+ let view = Ident::new("__tvm_ffi_match_any_view", span);
+ let rejected = Ident::new("__tvm_ffi_match_any_rejected", span);
+ let probe = Ident::new("__tvm_ffi_match_any_probe", span);
+ let pattern_list_id =
Ident::new("__tvm_ffi_match_any_leaf_pattern_list_id", span);
+ let type_indices = Ident::new("__tvm_ffi_match_any_type_indices", span);
+ let static_table = Ident::new("__TVM_FFI_MATCH_ANY_LEAF_TABLE", span);
+ let table = Ident::new("__tvm_ffi_match_any_leaf_table", span);
+ let arm_id = Ident::new("__tvm_ffi_match_any_arm_id", span);
+ let selected = Ident::new("__tvm_ffi_match_any_selected", span);
+ let selected_value = Ident::new("__tvm_ffi_match_any_selected_value",
span);
+ let selected_enum = Ident::new("__TvmFfiMatchAnyArm", span);
+ let fallback_variant = Ident::new("Fallback", span);
+ let arm_count = arms.len();
+ let matchers = arms.iter().map(|arm| &arm.matcher).collect::<Vec<_>>();
+ let arm_types = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("__TvmFfiMatchAnyType{arm_id}"),
span))
+ .collect::<Vec<_>>();
+ let arm_variants = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("Arm{arm_id}"), span))
+ .collect::<Vec<_>>();
+ let arm_constants = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("__TVM_FFI_MATCH_ANY_ARM_{arm_id}"),
span))
+ .collect::<Vec<_>>();
+ let arm_constant_definitions =
+ arm_constants
+ .iter()
+ .enumerate()
+ .map(|(arm_id, arm_constant)| {
+ quote! {
+ const #arm_constant: #tvm_ffi::match_any::ArmId =
+ #arm_id as #tvm_ffi::match_any::ArmId;
+ }
+ });
+ let lookup_entries = arm_constants
+ .iter()
+ .enumerate()
+ .map(|(arm_id, arm_constant)| quote!((#type_indices[#arm_id],
#arm_constant)));
+ let pattern_list = matchers
+ .iter()
+ .rev()
+ .fold(quote!(()), |tail, matcher| quote!((#matcher, #tail)));
+
+ let lookup_arm_id = quote! {
+ {
+ use #tvm_ffi::match_any::LeafPatternMetadata as _;
+
+ let #probe =
+ #tvm_ffi::match_any::LeafPatternProbe::<#pattern_list>::new();
+ match (&#probe).leaf_pattern_list_id() {
+ ::core::option::Option::Some(#pattern_list_id) => {
+ static #static_table: ::std::sync::OnceLock<
Review Comment:
one problem is that when the arm is something like `T()`, where `T` is
related to the external function, then the table may never be used
##########
rust/tvm-ffi-macros/src/match_any.rs:
##########
@@ -105,41 +110,225 @@ pub fn expand(input: proc_macro::TokenStream) ->
proc_macro::TokenStream {
fn expand_match_any(input: MatchAnyInput) -> TokenStream {
let tvm_ffi = get_tvm_ffi_crate();
+ let scrutinee = input.scrutinee;
+ let fallback = input.fallback;
+ let arms = input.arms;
+ let can_attempt_leaf_lookup = arms.len() >= MIN_LOOKUP_TABLE_ARMS
+ && arms
+ .iter()
+ .all(|arm| arm.guard.is_none() && is_simple_binding(&arm.binding));
+
+ if can_attempt_leaf_lookup {
+ expand_leaf_lookup_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ } else {
+ expand_ordered_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ }
+}
+
+fn expand_ordered_match(
+ tvm_ffi: &TokenStream,
+ scrutinee: &Expr,
+ arms: &[TypedArm],
+ fallback: &Expr,
+) -> TokenStream {
let span = Span::mixed_site();
let source = Ident::new("__tvm_ffi_match_any_source", span);
let converted = Ident::new("__tvm_ffi_match_any_converted", span);
let view = Ident::new("__tvm_ffi_match_any_view", span);
let rejected = Ident::new("__tvm_ffi_match_any_rejected", span);
- let scrutinee = input.scrutinee;
- let fallback = input.fallback;
- let dispatch_fallback = fallback.clone();
- let arms = input.arms;
- let dispatch = arms
- .into_iter()
- .rev()
- .fold(quote!({ #dispatch_fallback }), |next, arm| {
- let matcher = arm.matcher;
- let binding = arm.binding;
- let body = arm.body;
- let matched = if let Some(guard) = arm.guard {
- quote!(::core::result::Result::Ok(#binding) if #guard)
- } else {
- quote!(::core::result::Result::Ok(#binding))
+ let dispatch = expand_ordered_dispatch(arms, fallback, &view, &rejected);
+
+ quote! {
+ {
+ let #source = &(#scrutinee);
+ let #converted: ::core::result::Result<
+ #tvm_ffi::AnyView<'_>,
+ ::core::convert::Infallible,
+ > =
::core::convert::TryInto::<#tvm_ffi::AnyView<'_>>::try_into(#source);
+ let #view = match #converted {
+ ::core::result::Result::Ok(view) => view,
+ ::core::result::Result::Err(error) => match error {},
};
+ if #view.type_index()
+ >= #tvm_ffi::TypeIndex::kTVMFFIStaticObjectBegin as i32
+ {
+ #dispatch
+ } else {
+ #fallback
+ }
+ }
+ }
+}
+
+fn expand_ordered_dispatch(
+ arms: &[TypedArm],
+ fallback: &Expr,
+ view: &Ident,
+ rejected: &Ident,
+) -> TokenStream {
+ arms.iter().rev().fold(quote!({ #fallback }), |next, arm| {
+ let matcher = &arm.matcher;
+ let binding = &arm.binding;
+ let body = &arm.body;
+ let matched = if let Some(guard) = &arm.guard {
+ quote!(::core::result::Result::Ok(#binding) if #guard)
+ } else {
+ quote!(::core::result::Result::Ok(#binding))
+ };
+
+ quote! {
+ match ::core::convert::TryInto::<#matcher>::try_into(#view) {
+ #matched => { #body },
+ #rejected => {
+ ::core::mem::drop(#rejected);
+ #next
+ }
+ }
+ }
+ })
+}
+
+fn expand_leaf_lookup_match(
Review Comment:
breaking it into several parts may be better for understanding.
##########
rust/tvm-ffi-macros/src/match_any.rs:
##########
@@ -105,41 +110,225 @@ pub fn expand(input: proc_macro::TokenStream) ->
proc_macro::TokenStream {
fn expand_match_any(input: MatchAnyInput) -> TokenStream {
let tvm_ffi = get_tvm_ffi_crate();
+ let scrutinee = input.scrutinee;
+ let fallback = input.fallback;
+ let arms = input.arms;
+ let can_attempt_leaf_lookup = arms.len() >= MIN_LOOKUP_TABLE_ARMS
+ && arms
+ .iter()
+ .all(|arm| arm.guard.is_none() && is_simple_binding(&arm.binding));
+
+ if can_attempt_leaf_lookup {
+ expand_leaf_lookup_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ } else {
+ expand_ordered_match(&tvm_ffi, &scrutinee, &arms, &fallback)
+ }
+}
+
+fn expand_ordered_match(
+ tvm_ffi: &TokenStream,
+ scrutinee: &Expr,
+ arms: &[TypedArm],
+ fallback: &Expr,
+) -> TokenStream {
let span = Span::mixed_site();
let source = Ident::new("__tvm_ffi_match_any_source", span);
let converted = Ident::new("__tvm_ffi_match_any_converted", span);
let view = Ident::new("__tvm_ffi_match_any_view", span);
let rejected = Ident::new("__tvm_ffi_match_any_rejected", span);
- let scrutinee = input.scrutinee;
- let fallback = input.fallback;
- let dispatch_fallback = fallback.clone();
- let arms = input.arms;
- let dispatch = arms
- .into_iter()
- .rev()
- .fold(quote!({ #dispatch_fallback }), |next, arm| {
- let matcher = arm.matcher;
- let binding = arm.binding;
- let body = arm.body;
- let matched = if let Some(guard) = arm.guard {
- quote!(::core::result::Result::Ok(#binding) if #guard)
- } else {
- quote!(::core::result::Result::Ok(#binding))
+ let dispatch = expand_ordered_dispatch(arms, fallback, &view, &rejected);
+
+ quote! {
+ {
+ let #source = &(#scrutinee);
+ let #converted: ::core::result::Result<
+ #tvm_ffi::AnyView<'_>,
+ ::core::convert::Infallible,
+ > =
::core::convert::TryInto::<#tvm_ffi::AnyView<'_>>::try_into(#source);
+ let #view = match #converted {
+ ::core::result::Result::Ok(view) => view,
+ ::core::result::Result::Err(error) => match error {},
};
+ if #view.type_index()
+ >= #tvm_ffi::TypeIndex::kTVMFFIStaticObjectBegin as i32
+ {
+ #dispatch
+ } else {
+ #fallback
+ }
+ }
+ }
+}
+
+fn expand_ordered_dispatch(
+ arms: &[TypedArm],
+ fallback: &Expr,
+ view: &Ident,
+ rejected: &Ident,
+) -> TokenStream {
+ arms.iter().rev().fold(quote!({ #fallback }), |next, arm| {
+ let matcher = &arm.matcher;
+ let binding = &arm.binding;
+ let body = &arm.body;
+ let matched = if let Some(guard) = &arm.guard {
+ quote!(::core::result::Result::Ok(#binding) if #guard)
+ } else {
+ quote!(::core::result::Result::Ok(#binding))
+ };
+
+ quote! {
+ match ::core::convert::TryInto::<#matcher>::try_into(#view) {
+ #matched => { #body },
+ #rejected => {
+ ::core::mem::drop(#rejected);
+ #next
+ }
+ }
+ }
+ })
+}
+
+fn expand_leaf_lookup_match(
+ tvm_ffi: &TokenStream,
+ scrutinee: &Expr,
+ arms: &[TypedArm],
+ fallback: &Expr,
+) -> TokenStream {
+ let span = Span::mixed_site();
+ let source = Ident::new("__tvm_ffi_match_any_source", span);
+ let converted = Ident::new("__tvm_ffi_match_any_converted", span);
+ let view = Ident::new("__tvm_ffi_match_any_view", span);
+ let rejected = Ident::new("__tvm_ffi_match_any_rejected", span);
+ let probe = Ident::new("__tvm_ffi_match_any_probe", span);
+ let pattern_list_id =
Ident::new("__tvm_ffi_match_any_leaf_pattern_list_id", span);
+ let type_indices = Ident::new("__tvm_ffi_match_any_type_indices", span);
+ let static_table = Ident::new("__TVM_FFI_MATCH_ANY_LEAF_TABLE", span);
+ let table = Ident::new("__tvm_ffi_match_any_leaf_table", span);
+ let arm_id = Ident::new("__tvm_ffi_match_any_arm_id", span);
+ let selected = Ident::new("__tvm_ffi_match_any_selected", span);
+ let selected_value = Ident::new("__tvm_ffi_match_any_selected_value",
span);
+ let selected_enum = Ident::new("__TvmFfiMatchAnyArm", span);
+ let fallback_variant = Ident::new("Fallback", span);
+ let arm_count = arms.len();
+ let matchers = arms.iter().map(|arm| &arm.matcher).collect::<Vec<_>>();
+ let arm_types = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("__TvmFfiMatchAnyType{arm_id}"),
span))
+ .collect::<Vec<_>>();
+ let arm_variants = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("Arm{arm_id}"), span))
+ .collect::<Vec<_>>();
+ let arm_constants = (0..arm_count)
+ .map(|arm_id| Ident::new(&format!("__TVM_FFI_MATCH_ANY_ARM_{arm_id}"),
span))
+ .collect::<Vec<_>>();
+ let arm_constant_definitions =
+ arm_constants
+ .iter()
+ .enumerate()
+ .map(|(arm_id, arm_constant)| {
+ quote! {
+ const #arm_constant: #tvm_ffi::match_any::ArmId =
+ #arm_id as #tvm_ffi::match_any::ArmId;
+ }
+ });
+ let lookup_entries = arm_constants
+ .iter()
+ .enumerate()
+ .map(|(arm_id, arm_constant)| quote!((#type_indices[#arm_id],
#arm_constant)));
+ let pattern_list = matchers
+ .iter()
+ .rev()
+ .fold(quote!(()), |tail, matcher| quote!((#matcher, #tail)));
+
+ let lookup_arm_id = quote! {
+ {
+ use #tvm_ffi::match_any::LeafPatternMetadata as _;
+
+ let #probe =
+ #tvm_ffi::match_any::LeafPatternProbe::<#pattern_list>::new();
+ match (&#probe).leaf_pattern_list_id() {
+ ::core::option::Option::Some(#pattern_list_id) => {
+ static #static_table: ::std::sync::OnceLock<
+ #tvm_ffi::match_any::LeafLookupTable,
+ > = ::std::sync::OnceLock::new();
+ let #table = #static_table.get_or_init(|| {
+ let mut #type_indices = [0_i32; #arm_count];
+ (&#probe).fill_leaf_type_indices(&mut #type_indices);
+ #tvm_ffi::match_any::LeafLookupTable::build(
+ #pattern_list_id,
+ &[#(#lookup_entries),*],
+ )
+ });
+ #table.lookup(#pattern_list_id, #view.type_index())
+ }
+ ::core::option::Option::None => {
+ ::core::result::Result::Err(())
+ }
+ }
+ }
+ };
+
+ let ordered_selection = arms.iter().enumerate().rev().fold(
Review Comment:
can we reuse the previous logic
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