blob: 32486a4e0d7765f5e4d6c1e18f0152aaecc63e7b [file] [log] [blame]
// 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.
#include "src/tint/lang/wgsl/resolver/dependency_graph.h"
#include <string>
#include <utility>
#include <variant>
#include <vector>
#include "src/tint/lang/core/builtin.h"
#include "src/tint/lang/core/builtin_value.h"
#include "src/tint/lang/wgsl/ast/alias.h"
#include "src/tint/lang/wgsl/ast/assignment_statement.h"
#include "src/tint/lang/wgsl/ast/block_statement.h"
#include "src/tint/lang/wgsl/ast/break_if_statement.h"
#include "src/tint/lang/wgsl/ast/break_statement.h"
#include "src/tint/lang/wgsl/ast/call_statement.h"
#include "src/tint/lang/wgsl/ast/compound_assignment_statement.h"
#include "src/tint/lang/wgsl/ast/const.h"
#include "src/tint/lang/wgsl/ast/continue_statement.h"
#include "src/tint/lang/wgsl/ast/diagnostic_attribute.h"
#include "src/tint/lang/wgsl/ast/discard_statement.h"
#include "src/tint/lang/wgsl/ast/for_loop_statement.h"
#include "src/tint/lang/wgsl/ast/id_attribute.h"
#include "src/tint/lang/wgsl/ast/identifier.h"
#include "src/tint/lang/wgsl/ast/if_statement.h"
#include "src/tint/lang/wgsl/ast/increment_decrement_statement.h"
#include "src/tint/lang/wgsl/ast/index_attribute.h"
#include "src/tint/lang/wgsl/ast/internal_attribute.h"
#include "src/tint/lang/wgsl/ast/interpolate_attribute.h"
#include "src/tint/lang/wgsl/ast/invariant_attribute.h"
#include "src/tint/lang/wgsl/ast/let.h"
#include "src/tint/lang/wgsl/ast/location_attribute.h"
#include "src/tint/lang/wgsl/ast/loop_statement.h"
#include "src/tint/lang/wgsl/ast/must_use_attribute.h"
#include "src/tint/lang/wgsl/ast/override.h"
#include "src/tint/lang/wgsl/ast/return_statement.h"
#include "src/tint/lang/wgsl/ast/stage_attribute.h"
#include "src/tint/lang/wgsl/ast/stride_attribute.h"
#include "src/tint/lang/wgsl/ast/struct.h"
#include "src/tint/lang/wgsl/ast/struct_member_align_attribute.h"
#include "src/tint/lang/wgsl/ast/struct_member_offset_attribute.h"
#include "src/tint/lang/wgsl/ast/struct_member_size_attribute.h"
#include "src/tint/lang/wgsl/ast/switch_statement.h"
#include "src/tint/lang/wgsl/ast/templated_identifier.h"
#include "src/tint/lang/wgsl/ast/traverse_expressions.h"
#include "src/tint/lang/wgsl/ast/var.h"
#include "src/tint/lang/wgsl/ast/variable_decl_statement.h"
#include "src/tint/lang/wgsl/ast/while_statement.h"
#include "src/tint/lang/wgsl/ast/workgroup_attribute.h"
#include "src/tint/lang/wgsl/sem/builtin_fn.h"
#include "src/tint/utils/containers/map.h"
#include "src/tint/utils/containers/scope_stack.h"
#include "src/tint/utils/containers/unique_vector.h"
#include "src/tint/utils/macros/compiler.h"
#include "src/tint/utils/macros/defer.h"
#include "src/tint/utils/macros/scoped_assignment.h"
#include "src/tint/utils/memory/block_allocator.h"
#include "src/tint/utils/rtti/switch.h"
#include "src/tint/utils/text/string.h"
#include "src/tint/utils/text/string_stream.h"
#define TINT_DUMP_DEPENDENCY_GRAPH 0
namespace tint::resolver {
namespace {
// Forward declaration
struct Global;
/// Dependency describes how one global depends on another global
struct DependencyInfo {
/// The source of the symbol that forms the dependency
Source source;
};
/// DependencyEdge describes the two Globals used to define a dependency
/// relationship.
struct DependencyEdge {
/// The Global that depends on #to
const Global* from;
/// The Global that is depended on by #from
const Global* to;
};
/// DependencyEdgeCmp implements the contracts of std::equal_to<DependencyEdge>
/// and std::hash<DependencyEdge>.
struct DependencyEdgeCmp {
/// Equality operator
bool operator()(const DependencyEdge& lhs, const DependencyEdge& rhs) const {
return lhs.from == rhs.from && lhs.to == rhs.to;
}
/// Hashing operator
inline std::size_t operator()(const DependencyEdge& d) const { return Hash(d.from, d.to); }
};
/// A map of DependencyEdge to DependencyInfo
using DependencyEdges =
Hashmap<DependencyEdge, DependencyInfo, 64, DependencyEdgeCmp, DependencyEdgeCmp>;
/// Global describes a module-scope variable, type or function.
struct Global {
explicit Global(const ast::Node* n) : node(n) {}
/// The declaration ast::Node
const ast::Node* node;
/// A list of dependencies that this global depends on
Vector<Global*, 8> deps;
};
/// A map of global name to Global
using GlobalMap = Hashmap<Symbol, Global*, 16>;
/// Raises an ICE that a global ast::Node type was not handled by this system.
void UnhandledNode(const ast::Node* node) {
TINT_ICE() << "unhandled node type: " << node->TypeInfo().name;
}
/// Raises an error diagnostic with the given message and source.
void AddError(diag::List& diagnostics, const std::string& msg, const Source& source) {
diagnostics.add_error(diag::System::Resolver, msg, source);
}
/// Raises a note diagnostic with the given message and source.
void AddNote(diag::List& diagnostics, const std::string& msg, const Source& source) {
diagnostics.add_note(diag::System::Resolver, msg, source);
}
/// DependencyScanner is used to traverse a module to build the list of
/// global-to-global dependencies.
class DependencyScanner {
public:
/// Constructor
/// @param globals_by_name map of global symbol to Global pointer
/// @param diagnostics diagnostic messages, appended with any errors found
/// @param graph the dependency graph to populate with resolved symbols
/// @param edges the map of globals-to-global dependency edges, which will
/// be populated by calls to Scan()
DependencyScanner(const GlobalMap& globals_by_name,
diag::List& diagnostics,
DependencyGraph& graph,
DependencyEdges& edges)
: globals_(globals_by_name),
diagnostics_(diagnostics),
graph_(graph),
dependency_edges_(edges) {
// Register all the globals at global-scope
for (auto it : globals_by_name) {
scope_stack_.Set(it.key, it.value->node);
}
}
/// Walks the global declarations, resolving symbols, and determining the
/// dependencies of each global.
void Scan(Global* global) {
TINT_SCOPED_ASSIGNMENT(current_global_, global);
Switch(
global->node,
[&](const ast::Struct* str) {
Declare(str->name->symbol, str);
for (auto* member : str->members) {
TraverseAttributes(member->attributes);
TraverseExpression(member->type);
}
},
[&](const ast::Alias* alias) {
Declare(alias->name->symbol, alias);
TraverseExpression(alias->type);
},
[&](const ast::Function* func) {
Declare(func->name->symbol, func);
TraverseFunction(func);
},
[&](const ast::Variable* v) {
Declare(v->name->symbol, v);
TraverseVariable(v);
},
[&](const ast::DiagnosticDirective*) {
// Diagnostic directives do not affect the dependency graph.
},
[&](const ast::Enable*) {
// Enable directives do not affect the dependency graph.
},
[&](const ast::ConstAssert* assertion) { TraverseExpression(assertion->condition); },
[&](Default) { UnhandledNode(global->node); });
}
private:
/// Traverses the variable, performing symbol resolution.
void TraverseVariable(const ast::Variable* v) {
if (auto* var = v->As<ast::Var>()) {
TraverseExpression(var->declared_address_space);
TraverseExpression(var->declared_access);
}
TraverseExpression(v->type);
TraverseAttributes(v->attributes);
TraverseExpression(v->initializer);
}
/// Traverses the function, performing symbol resolution and determining global dependencies.
void TraverseFunction(const ast::Function* func) {
TraverseAttributes(func->attributes);
TraverseAttributes(func->return_type_attributes);
// Perform symbol resolution on all the parameter types before registering
// the parameters themselves. This allows the case of declaring a parameter
// with the same identifier as its type.
for (auto* param : func->params) {
TraverseAttributes(param->attributes);
TraverseExpression(param->type);
}
// Resolve the return type
TraverseExpression(func->return_type);
// Push the scope stack for the parameters and function body.
scope_stack_.Push();
TINT_DEFER(scope_stack_.Pop());
for (auto* param : func->params) {
if (auto* shadows = scope_stack_.Get(param->name->symbol)) {
graph_.shadows.Add(param, shadows);
}
Declare(param->name->symbol, param);
}
if (func->body) {
TraverseStatements(func->body->statements);
}
}
/// Traverses the statements, performing symbol resolution and determining
/// global dependencies.
void TraverseStatements(VectorRef<const ast::Statement*> stmts) {
for (auto* s : stmts) {
TraverseStatement(s);
}
}
/// Traverses the statement, performing symbol resolution and determining
/// global dependencies.
void TraverseStatement(const ast::Statement* stmt) {
if (!stmt) {
return;
}
Switch(
stmt, //
[&](const ast::AssignmentStatement* a) {
TraverseExpression(a->lhs);
TraverseExpression(a->rhs);
},
[&](const ast::BlockStatement* b) {
scope_stack_.Push();
TINT_DEFER(scope_stack_.Pop());
TraverseStatements(b->statements);
},
[&](const ast::BreakIfStatement* b) { TraverseExpression(b->condition); },
[&](const ast::CallStatement* r) { TraverseExpression(r->expr); },
[&](const ast::CompoundAssignmentStatement* a) {
TraverseExpression(a->lhs);
TraverseExpression(a->rhs);
},
[&](const ast::ForLoopStatement* l) {
scope_stack_.Push();
TINT_DEFER(scope_stack_.Pop());
TraverseStatement(l->initializer);
TraverseExpression(l->condition);
TraverseStatement(l->continuing);
TraverseStatement(l->body);
},
[&](const ast::IncrementDecrementStatement* i) { TraverseExpression(i->lhs); },
[&](const ast::LoopStatement* l) {
scope_stack_.Push();
TINT_DEFER(scope_stack_.Pop());
TraverseStatements(l->body->statements);
TraverseStatement(l->continuing);
},
[&](const ast::IfStatement* i) {
TraverseExpression(i->condition);
TraverseStatement(i->body);
if (i->else_statement) {
TraverseStatement(i->else_statement);
}
},
[&](const ast::ReturnStatement* r) { TraverseExpression(r->value); },
[&](const ast::SwitchStatement* s) {
TraverseExpression(s->condition);
for (auto* c : s->body) {
for (auto* sel : c->selectors) {
TraverseExpression(sel->expr);
}
TraverseStatement(c->body);
}
},
[&](const ast::VariableDeclStatement* v) {
if (auto* shadows = scope_stack_.Get(v->variable->name->symbol)) {
graph_.shadows.Add(v->variable, shadows);
}
TraverseVariable(v->variable);
Declare(v->variable->name->symbol, v->variable);
},
[&](const ast::WhileStatement* w) {
scope_stack_.Push();
TINT_DEFER(scope_stack_.Pop());
TraverseExpression(w->condition);
TraverseStatement(w->body);
},
[&](const ast::ConstAssert* assertion) { TraverseExpression(assertion->condition); },
[&](Default) {
if (TINT_UNLIKELY((!stmt->IsAnyOf<ast::BreakStatement, ast::ContinueStatement,
ast::DiscardStatement>()))) {
UnhandledNode(stmt);
}
});
}
/// Adds the symbol definition to the current scope, raising an error if two
/// symbols collide within the same scope.
void Declare(Symbol symbol, const ast::Node* node) {
auto* old = scope_stack_.Set(symbol, node);
if (old != nullptr && node != old) {
auto name = symbol.Name();
AddError(diagnostics_, "redeclaration of '" + name + "'", node->source);
AddNote(diagnostics_, "'" + name + "' previously declared here", old->source);
}
}
/// Traverses the expression @p root_expr, performing symbol resolution and determining global
/// dependencies.
void TraverseExpression(const ast::Expression* root_expr) {
if (!root_expr) {
return;
}
Vector<const ast::Expression*, 8> pending{root_expr};
while (!pending.IsEmpty()) {
auto* next = pending.Pop();
bool ok = ast::TraverseExpressions(next, [&](const ast::Expression* expr) {
Switch(
expr,
[&](const ast::IdentifierExpression* e) {
AddDependency(e->identifier, e->identifier->symbol);
if (auto* tmpl_ident = e->identifier->As<ast::TemplatedIdentifier>()) {
for (auto* arg : tmpl_ident->arguments) {
pending.Push(arg);
}
}
},
[&](const ast::CallExpression* call) { TraverseExpression(call->target); },
[&](const ast::BitcastExpression* cast) { TraverseExpression(cast->type); });
return ast::TraverseAction::Descend;
});
if (!ok) {
AddError(diagnostics_, "TraverseExpressions failed", next->source);
return;
}
}
}
/// Traverses the attribute list, performing symbol resolution and
/// determining global dependencies.
void TraverseAttributes(VectorRef<const ast::Attribute*> attrs) {
for (auto* attr : attrs) {
TraverseAttribute(attr);
}
}
/// Traverses the attribute, performing symbol resolution and determining
/// global dependencies.
void TraverseAttribute(const ast::Attribute* attr) {
bool handled = Switch(
attr,
[&](const ast::BindingAttribute* binding) {
TraverseExpression(binding->expr);
return true;
},
[&](const ast::BuiltinAttribute* builtin) {
TraverseExpression(builtin->builtin);
return true;
},
[&](const ast::GroupAttribute* group) {
TraverseExpression(group->expr);
return true;
},
[&](const ast::IdAttribute* id) {
TraverseExpression(id->expr);
return true;
},
[&](const ast::IndexAttribute* index) {
TraverseExpression(index->expr);
return true;
},
[&](const ast::InterpolateAttribute* interpolate) {
TraverseExpression(interpolate->type);
TraverseExpression(interpolate->sampling);
return true;
},
[&](const ast::LocationAttribute* loc) {
TraverseExpression(loc->expr);
return true;
},
[&](const ast::StructMemberAlignAttribute* align) {
TraverseExpression(align->expr);
return true;
},
[&](const ast::StructMemberSizeAttribute* size) {
TraverseExpression(size->expr);
return true;
},
[&](const ast::WorkgroupAttribute* wg) {
TraverseExpression(wg->x);
TraverseExpression(wg->y);
TraverseExpression(wg->z);
return true;
},
[&](const ast::InternalAttribute* i) {
for (auto* dep : i->dependencies) {
TraverseExpression(dep);
}
return true;
});
if (handled) {
return;
}
if (attr->IsAnyOf<ast::BuiltinAttribute, ast::DiagnosticAttribute,
ast::InterpolateAttribute, ast::InvariantAttribute, ast::MustUseAttribute,
ast::StageAttribute, ast::StrideAttribute,
ast::StructMemberOffsetAttribute>()) {
return;
}
UnhandledNode(attr);
}
/// The type of builtin that a symbol could represent.
enum class BuiltinType {
/// No builtin matched
kNone = 0,
/// Builtin function
kFunction,
/// Builtin
kBuiltin,
/// Builtin value
kBuiltinValue,
/// Address space
kAddressSpace,
/// Texel format
kTexelFormat,
/// Access
kAccess,
/// Interpolation Type
kInterpolationType,
/// Interpolation Sampling
kInterpolationSampling,
};
/// BuiltinInfo stores information about the builtin that a symbol represents.
struct BuiltinInfo {
/// @returns the builtin value
template <typename T>
T Value() const {
return std::get<T>(value);
}
BuiltinType type = BuiltinType::kNone;
std::variant<std::monostate,
core::BuiltinFn,
core::Builtin,
core::BuiltinValue,
core::AddressSpace,
core::TexelFormat,
core::Access,
core::InterpolationType,
core::InterpolationSampling>
value = {};
};
/// Get the builtin info for a given symbol.
/// @param symbol the symbol
/// @returns the builtin info
DependencyScanner::BuiltinInfo GetBuiltinInfo(Symbol symbol) {
return builtin_info_map.GetOrCreate(symbol, [&] {
if (auto builtin_fn = core::ParseBuiltinFn(symbol.NameView());
builtin_fn != core::BuiltinFn::kNone) {
return BuiltinInfo{BuiltinType::kFunction, builtin_fn};
}
if (auto builtin_ty = core::ParseBuiltin(symbol.NameView());
builtin_ty != core::Builtin::kUndefined) {
return BuiltinInfo{BuiltinType::kBuiltin, builtin_ty};
}
if (auto builtin_val = core::ParseBuiltinValue(symbol.NameView());
builtin_val != core::BuiltinValue::kUndefined) {
return BuiltinInfo{BuiltinType::kBuiltinValue, builtin_val};
}
if (auto addr = core::ParseAddressSpace(symbol.NameView());
addr != core::AddressSpace::kUndefined) {
return BuiltinInfo{BuiltinType::kAddressSpace, addr};
}
if (auto fmt = core::ParseTexelFormat(symbol.NameView());
fmt != core::TexelFormat::kUndefined) {
return BuiltinInfo{BuiltinType::kTexelFormat, fmt};
}
if (auto access = core::ParseAccess(symbol.NameView());
access != core::Access::kUndefined) {
return BuiltinInfo{BuiltinType::kAccess, access};
}
if (auto i_type = core::ParseInterpolationType(symbol.NameView());
i_type != core::InterpolationType::kUndefined) {
return BuiltinInfo{BuiltinType::kInterpolationType, i_type};
}
if (auto i_smpl = core::ParseInterpolationSampling(symbol.NameView());
i_smpl != core::InterpolationSampling::kUndefined) {
return BuiltinInfo{BuiltinType::kInterpolationSampling, i_smpl};
}
return BuiltinInfo{};
});
}
/// Adds the dependency from @p from to @p to, erroring if @p to cannot be resolved.
void AddDependency(const ast::Identifier* from, Symbol to) {
auto* resolved = scope_stack_.Get(to);
if (!resolved) {
auto builtin_info = GetBuiltinInfo(to);
switch (builtin_info.type) {
case BuiltinType::kNone:
graph_.resolved_identifiers.Add(from, UnresolvedIdentifier{to.Name()});
break;
case BuiltinType::kFunction:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::BuiltinFn>()));
break;
case BuiltinType::kBuiltin:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::Builtin>()));
break;
case BuiltinType::kBuiltinValue:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::BuiltinValue>()));
break;
case BuiltinType::kAddressSpace:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::AddressSpace>()));
break;
case BuiltinType::kTexelFormat:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::TexelFormat>()));
break;
case BuiltinType::kAccess:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::Access>()));
break;
case BuiltinType::kInterpolationType:
graph_.resolved_identifiers.Add(
from, ResolvedIdentifier(builtin_info.Value<core::InterpolationType>()));
break;
case BuiltinType::kInterpolationSampling:
graph_.resolved_identifiers.Add(
from,
ResolvedIdentifier(builtin_info.Value<core::InterpolationSampling>()));
break;
}
return;
}
if (auto global = globals_.Find(to); global && (*global)->node == resolved) {
if (dependency_edges_.Add(DependencyEdge{current_global_, *global},
DependencyInfo{from->source})) {
current_global_->deps.Push(*global);
}
}
graph_.resolved_identifiers.Add(from, ResolvedIdentifier(resolved));
}
using VariableMap = Hashmap<Symbol, const ast::Variable*, 32>;
const GlobalMap& globals_;
diag::List& diagnostics_;
DependencyGraph& graph_;
DependencyEdges& dependency_edges_;
ScopeStack<Symbol, const ast::Node*> scope_stack_;
Global* current_global_ = nullptr;
Hashmap<Symbol, BuiltinInfo, 64> builtin_info_map;
};
/// The global dependency analysis system
struct DependencyAnalysis {
public:
/// Constructor
DependencyAnalysis(diag::List& diagnostics, DependencyGraph& graph)
: diagnostics_(diagnostics), graph_(graph) {}
/// Performs global dependency analysis on the module, emitting any errors to
/// #diagnostics.
/// @returns true if analysis found no errors, otherwise false.
bool Run(const ast::Module& module) {
// Reserve container memory
graph_.resolved_identifiers.Reserve(module.GlobalDeclarations().Length());
sorted_.Reserve(module.GlobalDeclarations().Length());
// Collect all the named globals from the AST module
GatherGlobals(module);
// Traverse the named globals to build the dependency graph
DetermineDependencies();
// Sort the globals into dependency order
SortGlobals();
// Dump the dependency graph if TINT_DUMP_DEPENDENCY_GRAPH is non-zero
DumpDependencyGraph();
graph_.ordered_globals = sorted_.Release();
return !diagnostics_.contains_errors();
}
private:
/// @param node the ast::Node of the global declaration
/// @returns the symbol of the global declaration node
/// @note will raise an ICE if the node is not a type, function or variable
/// declaration
Symbol SymbolOf(const ast::Node* node) const {
return Switch(
node, //
[&](const ast::TypeDecl* td) { return td->name->symbol; },
[&](const ast::Function* func) { return func->name->symbol; },
[&](const ast::Variable* var) { return var->name->symbol; },
[&](const ast::DiagnosticDirective*) { return Symbol(); },
[&](const ast::Enable*) { return Symbol(); },
[&](const ast::ConstAssert*) { return Symbol(); },
[&](Default) {
UnhandledNode(node);
return Symbol{};
});
}
/// @param node the ast::Node of the global declaration
/// @returns the name of the global declaration node
/// @note will raise an ICE if the node is not a type, function or variable
/// declaration
std::string NameOf(const ast::Node* node) const { return SymbolOf(node).Name(); }
/// @param node the ast::Node of the global declaration
/// @returns a string representation of the global declaration kind
/// @note will raise an ICE if the node is not a type, function or variable
/// declaration
std::string KindOf(const ast::Node* node) {
return Switch(
node, //
[&](const ast::Struct*) { return "struct"; }, //
[&](const ast::Alias*) { return "alias"; }, //
[&](const ast::Function*) { return "function"; }, //
[&](const ast::Variable* v) { return v->Kind(); }, //
[&](const ast::ConstAssert*) { return "const_assert"; }, //
[&](Default) {
UnhandledNode(node);
return "<unknown>";
});
}
/// Traverses `module`, collecting all the global declarations and populating
/// the #globals and #declaration_order fields.
void GatherGlobals(const ast::Module& module) {
for (auto* node : module.GlobalDeclarations()) {
auto* global = allocator_.Create(node);
if (auto symbol = SymbolOf(node); symbol.IsValid()) {
globals_.Add(symbol, global);
}
declaration_order_.Push(global);
}
}
/// Walks the global declarations, determining the dependencies of each global
/// and adding these to each global's Global::deps field.
void DetermineDependencies() {
DependencyScanner scanner(globals_, diagnostics_, graph_, dependency_edges_);
for (auto* global : declaration_order_) {
scanner.Scan(global);
}
}
/// Performs a depth-first traversal of `root`'s dependencies, calling `enter`
/// as the function decends into each dependency and `exit` when bubbling back
/// up towards the root.
/// @param enter is a function with the signature: `bool(Global*)`. The
/// `enter` function returns true if TraverseDependencies() should traverse
/// the dependency, otherwise it will be skipped.
/// @param exit is a function with the signature: `void(Global*)`. The `exit`
/// function is only called if the corresponding `enter` call returned true.
template <typename ENTER, typename EXIT>
void TraverseDependencies(const Global* root, ENTER&& enter, EXIT&& exit) {
// Entry is a single entry in the traversal stack. Entry points to a
// dep_idx'th dependency of Entry::global.
struct Entry {
const Global* global; // The parent global
size_t dep_idx; // The dependency index in `global->deps`
};
if (!enter(root)) {
return;
}
Vector<Entry, 16> stack{Entry{root, 0}};
while (true) {
auto& entry = stack.Back();
// Have we exhausted the dependencies of entry.global?
if (entry.dep_idx < entry.global->deps.Length()) {
// No, there's more dependencies to traverse.
auto& dep = entry.global->deps[entry.dep_idx];
// Does the caller want to enter this dependency?
if (enter(dep)) { // Yes.
stack.Push(Entry{dep, 0}); // Enter the dependency.
} else {
entry.dep_idx++; // No. Skip this node.
}
} else {
// Yes. Time to back up.
// Exit this global, pop the stack, and if there's another parent node,
// increment its dependency index, and loop again.
exit(entry.global);
stack.Pop();
if (stack.IsEmpty()) {
return; // All done.
}
stack.Back().dep_idx++;
}
}
}
/// SortGlobals sorts the globals into dependency order, erroring if cyclic
/// dependencies are found. The sorted dependencies are assigned to #sorted.
void SortGlobals() {
if (diagnostics_.contains_errors()) {
return; // This code assumes there are no undeclared identifiers.
}
// Make sure all directives go before any other global declarations.
for (auto* global : declaration_order_) {
if (global->node->IsAnyOf<ast::DiagnosticDirective, ast::Enable>()) {
sorted_.Add(global->node);
}
}
for (auto* global : declaration_order_) {
if (global->node->IsAnyOf<ast::DiagnosticDirective, ast::Enable>()) {
// Skip directives here, as they are already added.
continue;
}
UniqueVector<const Global*, 8> stack;
TraverseDependencies(
global,
[&](const Global* g) { // Enter
if (!stack.Add(g)) {
CyclicDependencyFound(g, stack.Release());
return false;
}
if (sorted_.Contains(g->node)) {
// Visited this global already.
// stack was pushed, but exit() will not be called when we return
// false, so pop here.
stack.Pop();
return false;
}
return true;
},
[&](const Global* g) { // Exit. Only called if Enter returned true.
sorted_.Add(g->node);
stack.Pop();
});
sorted_.Add(global->node);
if (TINT_UNLIKELY(!stack.IsEmpty())) {
// Each stack.push() must have a corresponding stack.pop_back().
TINT_ICE() << "stack not empty after returning from TraverseDependencies()";
}
}
}
/// DepInfoFor() looks up the global dependency information for the dependency
/// of global `from` depending on `to`.
/// @note will raise an ICE if the edge is not found.
DependencyInfo DepInfoFor(const Global* from, const Global* to) const {
auto info = dependency_edges_.Find(DependencyEdge{from, to});
if (TINT_LIKELY(info)) {
return *info;
}
TINT_ICE() << "failed to find dependency info for edge: '" << NameOf(from->node) << "' -> '"
<< NameOf(to->node) << "'";
return {};
}
/// CyclicDependencyFound() emits an error diagnostic for a cyclic dependency.
/// @param root is the global that starts the cyclic dependency, which must be
/// found in `stack`.
/// @param stack is the global dependency stack that contains a loop.
void CyclicDependencyFound(const Global* root, VectorRef<const Global*> stack) {
StringStream msg;
msg << "cyclic dependency found: ";
constexpr size_t kLoopNotStarted = ~0u;
size_t loop_start = kLoopNotStarted;
for (size_t i = 0; i < stack.Length(); i++) {
auto* e = stack[i];
if (loop_start == kLoopNotStarted && e == root) {
loop_start = i;
}
if (loop_start != kLoopNotStarted) {
msg << "'" << NameOf(e->node) << "' -> ";
}
}
msg << "'" << NameOf(root->node) << "'";
AddError(diagnostics_, msg.str(), root->node->source);
for (size_t i = loop_start; i < stack.Length(); i++) {
auto* from = stack[i];
auto* to = (i + 1 < stack.Length()) ? stack[i + 1] : stack[loop_start];
auto info = DepInfoFor(from, to);
AddNote(diagnostics_,
KindOf(from->node) + " '" + NameOf(from->node) + "' references " +
KindOf(to->node) + " '" + NameOf(to->node) + "' here",
info.source);
}
}
void DumpDependencyGraph() {
#if TINT_DUMP_DEPENDENCY_GRAPH == 0
if ((true)) {
return;
}
#endif // TINT_DUMP_DEPENDENCY_GRAPH
printf("=========================\n");
printf("------ declaration ------ \n");
for (auto* global : declaration_order_) {
printf("%s\n", NameOf(global->node).c_str());
}
printf("------ dependencies ------ \n");
for (auto* node : sorted_) {
auto symbol = SymbolOf(node);
auto* global = *globals_.Find(symbol);
printf("%s depends on:\n", symbol.Name().c_str());
for (auto* dep : global->deps) {
printf(" %s\n", NameOf(dep->node).c_str());
}
}
printf("=========================\n");
}
/// Program diagnostics
diag::List& diagnostics_;
/// The resulting dependency graph
DependencyGraph& graph_;
/// Allocator of Globals
BlockAllocator<Global> allocator_;
/// Global map, keyed by name. Populated by GatherGlobals().
GlobalMap globals_;
/// Map of DependencyEdge to DependencyInfo. Populated by DetermineDependencies().
DependencyEdges dependency_edges_;
/// Globals in declaration order. Populated by GatherGlobals().
Vector<Global*, 64> declaration_order_;
/// Globals in sorted dependency order. Populated by SortGlobals().
UniqueVector<const ast::Node*, 64> sorted_;
};
} // namespace
DependencyGraph::DependencyGraph() = default;
DependencyGraph::DependencyGraph(DependencyGraph&&) = default;
DependencyGraph::~DependencyGraph() = default;
bool DependencyGraph::Build(const ast::Module& module,
diag::List& diagnostics,
DependencyGraph& output) {
DependencyAnalysis da{diagnostics, output};
return da.Run(module);
}
std::string ResolvedIdentifier::String() const {
if (auto* node = Node()) {
return Switch(
node,
[&](const ast::TypeDecl* n) { //
return "type '" + n->name->symbol.Name() + "'";
},
[&](const ast::Var* n) { //
return "var '" + n->name->symbol.Name() + "'";
},
[&](const ast::Let* n) { //
return "let '" + n->name->symbol.Name() + "'";
},
[&](const ast::Const* n) { //
return "const '" + n->name->symbol.Name() + "'";
},
[&](const ast::Override* n) { //
return "override '" + n->name->symbol.Name() + "'";
},
[&](const ast::Function* n) { //
return "function '" + n->name->symbol.Name() + "'";
},
[&](const ast::Parameter* n) { //
return "parameter '" + n->name->symbol.Name() + "'";
},
[&](Default) {
TINT_UNREACHABLE() << "unhandled ast::Node: " << node->TypeInfo().name;
return "<unknown>";
});
}
if (auto builtin_fn = BuiltinFn(); builtin_fn != core::BuiltinFn::kNone) {
return "builtin function '" + tint::ToString(builtin_fn) + "'";
}
if (auto builtin_ty = BuiltinType(); builtin_ty != core::Builtin::kUndefined) {
return "builtin type '" + tint::ToString(builtin_ty) + "'";
}
if (auto builtin_val = BuiltinValue(); builtin_val != core::BuiltinValue::kUndefined) {
return "builtin value '" + tint::ToString(builtin_val) + "'";
}
if (auto access = Access(); access != core::Access::kUndefined) {
return "access '" + tint::ToString(access) + "'";
}
if (auto addr = AddressSpace(); addr != core::AddressSpace::kUndefined) {
return "address space '" + tint::ToString(addr) + "'";
}
if (auto type = InterpolationType(); type != core::InterpolationType::kUndefined) {
return "interpolation type '" + tint::ToString(type) + "'";
}
if (auto smpl = InterpolationSampling(); smpl != core::InterpolationSampling::kUndefined) {
return "interpolation sampling '" + tint::ToString(smpl) + "'";
}
if (auto fmt = TexelFormat(); fmt != core::TexelFormat::kUndefined) {
return "texel format '" + tint::ToString(fmt) + "'";
}
if (auto* unresolved = Unresolved()) {
return "unresolved identifier '" + unresolved->name + "'";
}
TINT_UNREACHABLE() << "unhandled ResolvedIdentifier";
return "<unknown>";
}
} // namespace tint::resolver