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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gen
import (
"crypto/sha256"
"encoding/hex"
"fmt"
"strings"
"dawn.googlesource.com/dawn/tools/src/fileutils"
"dawn.googlesource.com/dawn/tools/src/tint/intrinsic/sem"
)
// Permuter generates permutations of intrinsic overloads
type Permuter struct {
sem *sem.Sem
allTypes []sem.FullyQualifiedName
}
// NewPermuter returns a new initialized Permuter
func NewPermuter(s *sem.Sem) (*Permuter, error) {
// allTypes are the list of FQNs that are used for unconstrained types
allTypes := []sem.FullyQualifiedName{}
for _, ty := range s.Types {
if len(ty.TemplateParams) > 0 {
// Ignore aggregate types for now.
// TODO(bclayton): Support a limited set of aggregate types
continue
}
allTypes = append(allTypes, sem.FullyQualifiedName{Target: ty})
}
return &Permuter{
sem: s,
allTypes: allTypes,
}, nil
}
// Permutation describes a single permutation of an overload
type Permutation struct {
sem.Overload // The permutated overload signature
Desc string // Description of the overload
Hash string // Hash of the overload
}
// Permute generates a set of permutations for the given intrinsic overload
func (p *Permuter) Permute(overload *sem.Overload) ([]Permutation, error) {
state := permutationState{
Permuter: p,
templateTypes: map[sem.TemplateParam]sem.FullyQualifiedName{},
templateNumbers: map[sem.TemplateParam]interface{}{},
parameters: map[int]sem.FullyQualifiedName{},
}
out := []Permutation{}
// Map of hash to permutation description. Used to detect collisions.
hashes := map[string]string{}
// permutate appends a permutation to out.
// permutate may be chained to generate N-dimensional permutations.
permutate := func() error {
o := sem.Overload{
Decl: overload.Decl,
Intrinsic: overload.Intrinsic,
CanBeUsedInStage: overload.CanBeUsedInStage,
}
for i, p := range overload.Parameters {
ty := state.parameters[i]
if !validate(ty, &o.CanBeUsedInStage) {
return nil
}
o.Parameters = append(o.Parameters, sem.Parameter{
Name: p.Name,
Type: ty,
IsConst: p.IsConst,
})
}
if overload.ReturnType != nil {
retTys, err := state.permutateFQN(*overload.ReturnType)
if err != nil {
return fmt.Errorf("while permutating return type: %w", err)
}
if len(retTys) != 1 {
return fmt.Errorf("result type not pinned")
}
o.ReturnType = &retTys[0]
}
desc := fmt.Sprint(o)
hash := sha256.Sum256([]byte(desc))
const hashLength = 6
shortHash := hex.EncodeToString(hash[:])[:hashLength]
out = append(out, Permutation{
Overload: o,
Desc: desc,
Hash: shortHash,
})
// Check for hash collisions
if existing, collision := hashes[shortHash]; collision {
return fmt.Errorf("hash '%v' collision between %v and %v\nIncrease hashLength in %v",
shortHash, existing, desc, fileutils.GoSourcePath())
}
hashes[shortHash] = desc
return nil
}
for i, param := range overload.Parameters {
i, param := i, param // Capture iterator values for anonymous function
next := permutate // Permutation chaining
permutate = func() error {
permutations, err := state.permutateFQN(param.Type)
if err != nil {
return fmt.Errorf("while processing parameter %v: %w", i, err)
}
if len(permutations) == 0 {
return fmt.Errorf("parameter %v has no permutations", i)
}
for _, fqn := range permutations {
state.parameters[i] = fqn
if err := next(); err != nil {
return err
}
}
return nil
}
}
for _, t := range overload.TemplateParams {
next := permutate // Permutation chaining
switch t := t.(type) {
case *sem.TemplateTypeParam:
types := p.allTypes
if t.Type != nil {
var err error
types, err = state.permutateFQN(sem.FullyQualifiedName{Target: t.Type})
if err != nil {
return nil, fmt.Errorf("while permutating template types: %w", err)
}
}
if len(types) == 0 {
return nil, fmt.Errorf("template type %v has no permutations", t.Name)
}
permutate = func() error {
for _, ty := range types {
state.templateTypes[t] = ty
if err := next(); err != nil {
return err
}
}
return nil
}
case *sem.TemplateEnumParam:
var permutations []sem.FullyQualifiedName
var err error
if t.Matcher != nil {
permutations, err = state.permutateFQN(sem.FullyQualifiedName{Target: t.Matcher})
} else {
permutations, err = state.permutateFQN(sem.FullyQualifiedName{Target: t.Enum})
}
if err != nil {
return nil, fmt.Errorf("while permutating template numbers: %w", err)
}
if len(permutations) == 0 {
return nil, fmt.Errorf("template type %v has no permutations", t.Name)
}
permutate = func() error {
for _, n := range permutations {
state.templateNumbers[t] = n
if err := next(); err != nil {
return err
}
}
return nil
}
case *sem.TemplateNumberParam:
// Currently all open numbers are used for vector / matrices
permutations := []int{2, 3, 4}
permutate = func() error {
for _, n := range permutations {
state.templateNumbers[t] = n
if err := next(); err != nil {
return err
}
}
return nil
}
}
}
if err := permutate(); err != nil {
return nil, fmt.Errorf("%v %v %w\nState: %v", overload.Decl.Source, overload.Decl, err, state)
}
return out, nil
}
type permutationState struct {
*Permuter
templateTypes map[sem.TemplateParam]sem.FullyQualifiedName
templateNumbers map[sem.TemplateParam]interface{}
parameters map[int]sem.FullyQualifiedName
}
func (s permutationState) String() string {
sb := &strings.Builder{}
sb.WriteString("Template types:\n")
for ct, ty := range s.templateTypes {
fmt.Fprintf(sb, " %v: %v\n", ct.GetName(), ty)
}
sb.WriteString("Template numbers:\n")
for cn, v := range s.templateNumbers {
fmt.Fprintf(sb, " %v: %v\n", cn.GetName(), v)
}
return sb.String()
}
func (s *permutationState) permutateFQN(in sem.FullyQualifiedName) ([]sem.FullyQualifiedName, error) {
args := append([]interface{}{}, in.TemplateArguments...)
out := []sem.FullyQualifiedName{}
// permutate appends a permutation to out.
// permutate may be chained to generate N-dimensional permutations.
var permutate func() error
switch target := in.Target.(type) {
case *sem.Type:
permutate = func() error {
out = append(out, sem.FullyQualifiedName{Target: in.Target, TemplateArguments: args})
args = append([]interface{}{}, in.TemplateArguments...)
return nil
}
case sem.TemplateParam:
if ty, ok := s.templateTypes[target]; ok {
permutate = func() error {
out = append(out, ty)
return nil
}
} else {
return nil, fmt.Errorf("'%v' was not found in templateTypes", target.GetName())
}
case *sem.TypeMatcher:
permutate = func() error {
for _, ty := range target.Types {
out = append(out, sem.FullyQualifiedName{Target: ty})
}
return nil
}
case *sem.EnumMatcher:
permutate = func() error {
for _, o := range target.Options {
if !o.IsInternal {
out = append(out, sem.FullyQualifiedName{Target: o})
}
}
return nil
}
case *sem.Enum:
permutate = func() error {
for _, e := range target.Entries {
if !e.IsInternal {
out = append(out, sem.FullyQualifiedName{Target: e})
}
}
return nil
}
default:
return nil, fmt.Errorf("unhandled target type: %T", in.Target)
}
for i, arg := range in.TemplateArguments {
i := i // Capture iterator value for anonymous functions
next := permutate // Permutation chaining
switch arg := arg.(type) {
case sem.FullyQualifiedName:
switch target := arg.Target.(type) {
case sem.TemplateParam:
if ty, ok := s.templateTypes[target]; ok {
args[i] = ty
} else if num, ok := s.templateNumbers[target]; ok {
args[i] = num
} else {
return nil, fmt.Errorf("'%v' was not found in templateTypes or templateNumbers", target.GetName())
}
default:
perms, err := s.permutateFQN(arg)
if err != nil {
return nil, fmt.Errorf("while processing template argument %v: %v", i, err)
}
if len(perms) == 0 {
return nil, fmt.Errorf("template argument %v has no permutations", i)
}
permutate = func() error {
for _, f := range perms {
args[i] = f
if err := next(); err != nil {
return err
}
}
return nil
}
}
default:
return nil, fmt.Errorf("permutateFQN() unhandled template argument type: %T", arg)
}
}
if err := permutate(); err != nil {
return nil, fmt.Errorf("while processing fully qualified name '%v': %w", in.Target.GetName(), err)
}
return out, nil
}
func validate(fqn sem.FullyQualifiedName, uses *sem.StageUses) bool {
if strings.HasPrefix(fqn.Target.GetName(), "_") {
return false // Builtin, untypeable return type
}
switch fqn.Target.GetName() {
case "array":
elTy := fqn.TemplateArguments[0].(sem.FullyQualifiedName)
elTyName := elTy.Target.GetName()
switch {
case elTyName == "bool" ||
strings.Contains(elTyName, "sampler"),
strings.Contains(elTyName, "texture"):
return false // Not storable
case IsAbstract(DeepestElementType(elTy)):
return false // Abstract types are not typeable
}
case "ptr":
// https://gpuweb.github.io/gpuweb/wgsl/#storage-class
access := fqn.TemplateArguments[2].(sem.FullyQualifiedName).Target.(*sem.EnumEntry).Name
storageClass := fqn.TemplateArguments[0].(sem.FullyQualifiedName).Target.(*sem.EnumEntry).Name
switch storageClass {
case "function", "private":
if access != "read_write" {
return false
}
case "workgroup":
uses.Vertex = false
uses.Fragment = false
if access != "read_write" {
return false
}
case "uniform":
if access != "read" {
return false
}
case "storage":
if access != "read_write" && access != "read" {
return false
}
case "handle":
if access != "read" {
return false
}
default:
return false
}
}
for _, arg := range fqn.TemplateArguments {
if argFQN, ok := arg.(sem.FullyQualifiedName); ok {
if !validate(argFQN, uses) {
return false
}
}
}
return true
}