| // 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/resolver/dependency_graph.h" |
| |
| #include <string> |
| #include <unordered_set> |
| #include <utility> |
| #include <vector> |
| |
| #include "src/tint/ast/alias.h" |
| #include "src/tint/ast/array.h" |
| #include "src/tint/ast/assignment_statement.h" |
| #include "src/tint/ast/atomic.h" |
| #include "src/tint/ast/block_statement.h" |
| #include "src/tint/ast/bool.h" |
| #include "src/tint/ast/break_statement.h" |
| #include "src/tint/ast/call_statement.h" |
| #include "src/tint/ast/compound_assignment_statement.h" |
| #include "src/tint/ast/continue_statement.h" |
| #include "src/tint/ast/depth_multisampled_texture.h" |
| #include "src/tint/ast/depth_texture.h" |
| #include "src/tint/ast/discard_statement.h" |
| #include "src/tint/ast/external_texture.h" |
| #include "src/tint/ast/f16.h" |
| #include "src/tint/ast/f32.h" |
| #include "src/tint/ast/fallthrough_statement.h" |
| #include "src/tint/ast/for_loop_statement.h" |
| #include "src/tint/ast/i32.h" |
| #include "src/tint/ast/id_attribute.h" |
| #include "src/tint/ast/if_statement.h" |
| #include "src/tint/ast/increment_decrement_statement.h" |
| #include "src/tint/ast/internal_attribute.h" |
| #include "src/tint/ast/interpolate_attribute.h" |
| #include "src/tint/ast/invariant_attribute.h" |
| #include "src/tint/ast/location_attribute.h" |
| #include "src/tint/ast/loop_statement.h" |
| #include "src/tint/ast/matrix.h" |
| #include "src/tint/ast/multisampled_texture.h" |
| #include "src/tint/ast/pointer.h" |
| #include "src/tint/ast/return_statement.h" |
| #include "src/tint/ast/sampled_texture.h" |
| #include "src/tint/ast/stage_attribute.h" |
| #include "src/tint/ast/storage_texture.h" |
| #include "src/tint/ast/stride_attribute.h" |
| #include "src/tint/ast/struct.h" |
| #include "src/tint/ast/struct_member_align_attribute.h" |
| #include "src/tint/ast/struct_member_offset_attribute.h" |
| #include "src/tint/ast/struct_member_size_attribute.h" |
| #include "src/tint/ast/switch_statement.h" |
| #include "src/tint/ast/traverse_expressions.h" |
| #include "src/tint/ast/type_name.h" |
| #include "src/tint/ast/u32.h" |
| #include "src/tint/ast/variable_decl_statement.h" |
| #include "src/tint/ast/vector.h" |
| #include "src/tint/ast/void.h" |
| #include "src/tint/ast/while_statement.h" |
| #include "src/tint/ast/workgroup_attribute.h" |
| #include "src/tint/scope_stack.h" |
| #include "src/tint/sem/builtin.h" |
| #include "src/tint/symbol_table.h" |
| #include "src/tint/utils/block_allocator.h" |
| #include "src/tint/utils/defer.h" |
| #include "src/tint/utils/map.h" |
| #include "src/tint/utils/scoped_assignment.h" |
| #include "src/tint/utils/unique_vector.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; |
| /// A string describing how the dependency is referenced. e.g. 'calls' |
| const char* action = nullptr; |
| }; |
| |
| /// 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 utils::Hash(d.from, d.to); |
| } |
| }; |
| |
| /// A map of DependencyEdge to DependencyInfo |
| using DependencyEdges = |
| std::unordered_map<DependencyEdge, DependencyInfo, 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 |
| std::vector<Global*> deps; |
| }; |
| |
| /// A map of global name to Global |
| using GlobalMap = std::unordered_map<Symbol, Global*>; |
| |
| /// Raises an ICE that a global ast::Node type was not handled by this system. |
| void UnhandledNode(diag::List& diagnostics, const ast::Node* node) { |
| TINT_ICE(Resolver, diagnostics) << "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 syms the program symbol table |
| /// @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 SymbolTable& syms, |
| const GlobalMap& globals_by_name, |
| diag::List& diagnostics, |
| DependencyGraph& graph, |
| DependencyEdges& edges) |
| : symbols_(syms), |
| 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.first, it.second->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, str); |
| for (auto* member : str->members) { |
| TraverseType(member->type); |
| } |
| }, |
| [&](const ast::Alias* alias) { |
| Declare(alias->name, alias); |
| TraverseType(alias->type); |
| }, |
| [&](const ast::Function* func) { |
| Declare(func->symbol, func); |
| TraverseAttributes(func->attributes); |
| TraverseFunction(func); |
| }, |
| [&](const ast::Variable* var) { |
| Declare(var->symbol, var); |
| TraverseType(var->type); |
| if (var->constructor) { |
| TraverseExpression(var->constructor); |
| } |
| }, |
| [&](const ast::Enable*) { |
| // Enable directives do not effect the dependency graph. |
| }, |
| [&](const ast::StaticAssert* assertion) { TraverseExpression(assertion->condition); }, |
| [&](Default) { UnhandledNode(diagnostics_, global->node); }); |
| } |
| |
| private: |
| /// Traverses the function, performing symbol resolution and determining |
| /// global dependencies. |
| void TraverseFunction(const ast::Function* func) { |
| // 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) { |
| TraverseType(param->type); |
| } |
| // Resolve the return type |
| TraverseType(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->symbol)) { |
| graph_.shadows.emplace(param, shadows); |
| } |
| Declare(param->symbol, param); |
| } |
| if (func->body) { |
| TraverseStatements(func->body->statements); |
| } |
| } |
| |
| /// Traverses the statements, performing symbol resolution and determining |
| /// global dependencies. |
| void TraverseStatements(utils::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::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); |
| } |
| TraverseStatement(c->body); |
| } |
| }, |
| [&](const ast::VariableDeclStatement* v) { |
| if (auto* shadows = scope_stack_.Get(v->variable->symbol)) { |
| graph_.shadows.emplace(v->variable, shadows); |
| } |
| TraverseType(v->variable->type); |
| TraverseExpression(v->variable->constructor); |
| Declare(v->variable->symbol, v->variable); |
| }, |
| [&](const ast::WhileStatement* w) { |
| scope_stack_.Push(); |
| TINT_DEFER(scope_stack_.Pop()); |
| TraverseExpression(w->condition); |
| TraverseStatement(w->body); |
| }, |
| [&](const ast::StaticAssert* assertion) { TraverseExpression(assertion->condition); }, |
| [&](Default) { |
| if (!stmt->IsAnyOf<ast::BreakStatement, ast::ContinueStatement, |
| ast::DiscardStatement, ast::FallthroughStatement>()) { |
| UnhandledNode(diagnostics_, 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 = symbols_.NameFor(symbol); |
| AddError(diagnostics_, "redeclaration of '" + name + "'", node->source); |
| AddNote(diagnostics_, "'" + name + "' previously declared here", old->source); |
| } |
| } |
| |
| /// Traverses the expression, performing symbol resolution and determining |
| /// global dependencies. |
| void TraverseExpression(const ast::Expression* root) { |
| if (!root) { |
| return; |
| } |
| ast::TraverseExpressions(root, diagnostics_, [&](const ast::Expression* expr) { |
| Switch( |
| expr, |
| [&](const ast::IdentifierExpression* ident) { |
| AddDependency(ident, ident->symbol, "identifier", "references"); |
| }, |
| [&](const ast::CallExpression* call) { |
| if (call->target.name) { |
| AddDependency(call->target.name, call->target.name->symbol, "function", |
| "calls"); |
| } |
| if (call->target.type) { |
| TraverseType(call->target.type); |
| } |
| }, |
| [&](const ast::BitcastExpression* cast) { TraverseType(cast->type); }); |
| return ast::TraverseAction::Descend; |
| }); |
| } |
| |
| /// Traverses the type node, performing symbol resolution and determining |
| /// global dependencies. |
| void TraverseType(const ast::Type* ty) { |
| if (!ty) { |
| return; |
| } |
| Switch( |
| ty, // |
| [&](const ast::Array* arr) { |
| TraverseType(arr->type); // |
| TraverseExpression(arr->count); |
| }, |
| [&](const ast::Atomic* atomic) { // |
| TraverseType(atomic->type); |
| }, |
| [&](const ast::Matrix* mat) { // |
| TraverseType(mat->type); |
| }, |
| [&](const ast::Pointer* ptr) { // |
| TraverseType(ptr->type); |
| }, |
| [&](const ast::TypeName* tn) { // |
| AddDependency(tn, tn->name, "type", "references"); |
| }, |
| [&](const ast::Vector* vec) { // |
| TraverseType(vec->type); |
| }, |
| [&](const ast::SampledTexture* tex) { // |
| TraverseType(tex->type); |
| }, |
| [&](const ast::MultisampledTexture* tex) { // |
| TraverseType(tex->type); |
| }, |
| [&](Default) { |
| if (!ty->IsAnyOf<ast::Void, ast::Bool, ast::I32, ast::U32, ast::F16, ast::F32, |
| ast::DepthTexture, ast::DepthMultisampledTexture, |
| ast::StorageTexture, ast::ExternalTexture, ast::Sampler>()) { |
| UnhandledNode(diagnostics_, ty); |
| } |
| }); |
| } |
| |
| /// Traverses the attribute list, performing symbol resolution and |
| /// determining global dependencies. |
| void TraverseAttributes(utils::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) { |
| if (auto* wg = attr->As<ast::WorkgroupAttribute>()) { |
| TraverseExpression(wg->x); |
| TraverseExpression(wg->y); |
| TraverseExpression(wg->z); |
| return; |
| } |
| if (attr->IsAnyOf<ast::BindingAttribute, ast::BuiltinAttribute, ast::GroupAttribute, |
| ast::IdAttribute, ast::InternalAttribute, ast::InterpolateAttribute, |
| ast::InvariantAttribute, ast::LocationAttribute, ast::StageAttribute, |
| ast::StrideAttribute, ast::StructMemberAlignAttribute, |
| ast::StructMemberOffsetAttribute, ast::StructMemberSizeAttribute>()) { |
| return; |
| } |
| |
| UnhandledNode(diagnostics_, attr); |
| } |
| |
| /// Adds the dependency from `from` to `to`, erroring if `to` cannot be |
| /// resolved. |
| void AddDependency(const ast::Node* from, Symbol to, const char* use, const char* action) { |
| auto* resolved = scope_stack_.Get(to); |
| if (!resolved) { |
| if (!IsBuiltin(to)) { |
| UnknownSymbol(to, from->source, use); |
| return; |
| } |
| } |
| |
| if (auto* global = utils::Lookup(globals_, to); global && global->node == resolved) { |
| if (dependency_edges_ |
| .emplace(DependencyEdge{current_global_, global}, |
| DependencyInfo{from->source, action}) |
| .second) { |
| current_global_->deps.emplace_back(global); |
| } |
| } |
| |
| graph_.resolved_symbols.emplace(from, resolved); |
| } |
| |
| /// @returns true if `name` is the name of a builtin function |
| bool IsBuiltin(Symbol name) const { |
| return sem::ParseBuiltinType(symbols_.NameFor(name)) != sem::BuiltinType::kNone; |
| } |
| |
| /// Appends an error to the diagnostics that the given symbol cannot be |
| /// resolved. |
| void UnknownSymbol(Symbol name, Source source, const char* use) { |
| AddError(diagnostics_, "unknown " + std::string(use) + ": '" + symbols_.NameFor(name) + "'", |
| source); |
| } |
| |
| using VariableMap = std::unordered_map<Symbol, const ast::Variable*>; |
| const SymbolTable& symbols_; |
| const GlobalMap& globals_; |
| diag::List& diagnostics_; |
| DependencyGraph& graph_; |
| DependencyEdges& dependency_edges_; |
| |
| ScopeStack<Symbol, const ast::Node*> scope_stack_; |
| Global* current_global_ = nullptr; |
| }; |
| |
| /// The global dependency analysis system |
| struct DependencyAnalysis { |
| public: |
| /// Constructor |
| DependencyAnalysis(const SymbolTable& symbols, diag::List& diagnostics, DependencyGraph& graph) |
| : symbols_(symbols), 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_symbols.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 = std::move(sorted_); |
| |
| 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; }, |
| [&](const ast::Function* func) { return func->symbol; }, |
| [&](const ast::Variable* var) { return var->symbol; }, |
| [&](const ast::Enable*) { return Symbol(); }, |
| [&](const ast::StaticAssert*) { return Symbol(); }, |
| [&](Default) { |
| UnhandledNode(diagnostics_, 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 symbols_.NameFor(SymbolOf(node)); } |
| |
| /// @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::StaticAssert*) { return "static_assert"; }, // |
| [&](Default) { |
| UnhandledNode(diagnostics_, node); |
| return "<error>"; |
| }); |
| } |
| |
| /// 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_.emplace(symbol, global); |
| } |
| declaration_order_.emplace_back(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(symbols_, 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; |
| } |
| |
| std::vector<Entry> 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.size()) { |
| // 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_back(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_back(); |
| if (stack.empty()) { |
| 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 'enable' directives go before any other global declarations. |
| for (auto* global : declaration_order_) { |
| if (auto* enable = global->node->As<ast::Enable>()) { |
| sorted_.add(enable); |
| } |
| } |
| |
| for (auto* global : declaration_order_) { |
| if (global->node->Is<ast::Enable>()) { |
| // Skip 'enable' directives here, as they are already added. |
| continue; |
| } |
| utils::UniqueVector<const Global*> stack; |
| TraverseDependencies( |
| global, |
| [&](const Global* g) { // Enter |
| if (!stack.add(g)) { |
| CyclicDependencyFound(g, stack); |
| 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_back(); |
| return false; |
| } |
| return true; |
| }, |
| [&](const Global* g) { // Exit. Only called if Enter returned true. |
| sorted_.add(g->node); |
| stack.pop_back(); |
| }); |
| |
| sorted_.add(global->node); |
| |
| if (!stack.empty()) { |
| // Each stack.push() must have a corresponding stack.pop_back(). |
| TINT_ICE(Resolver, diagnostics_) |
| << "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 it = dependency_edges_.find(DependencyEdge{from, to}); |
| if (it != dependency_edges_.end()) { |
| return it->second; |
| } |
| TINT_ICE(Resolver, diagnostics_) |
| << "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, const std::vector<const Global*>& stack) { |
| std::stringstream msg; |
| msg << "cyclic dependency found: "; |
| constexpr size_t kLoopNotStarted = ~0u; |
| size_t loop_start = kLoopNotStarted; |
| for (size_t i = 0; i < stack.size(); 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.size(); i++) { |
| auto* from = stack[i]; |
| auto* to = (i + 1 < stack.size()) ? stack[i + 1] : stack[loop_start]; |
| auto info = DepInfoFor(from, to); |
| AddNote(diagnostics_, |
| KindOf(from->node) + " '" + NameOf(from->node) + "' " + info.action + " " + |
| 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_.at(symbol); |
| printf("%s depends on:\n", symbols_.NameFor(symbol).c_str()); |
| for (auto* dep : global->deps) { |
| printf(" %s\n", NameOf(dep->node).c_str()); |
| } |
| } |
| printf("=========================\n"); |
| } |
| |
| /// Program symbols |
| const SymbolTable& symbols_; |
| |
| /// Program diagnostics |
| diag::List& diagnostics_; |
| |
| /// The resulting dependency graph |
| DependencyGraph& graph_; |
| |
| /// Allocator of Globals |
| utils::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(). |
| std::vector<Global*> declaration_order_; |
| |
| /// Globals in sorted dependency order. Populated by SortGlobals(). |
| utils::UniqueVector<const ast::Node*> sorted_; |
| }; |
| |
| } // namespace |
| |
| DependencyGraph::DependencyGraph() = default; |
| DependencyGraph::DependencyGraph(DependencyGraph&&) = default; |
| DependencyGraph::~DependencyGraph() = default; |
| |
| bool DependencyGraph::Build(const ast::Module& module, |
| const SymbolTable& symbols, |
| diag::List& diagnostics, |
| DependencyGraph& output) { |
| DependencyAnalysis da{symbols, diagnostics, output}; |
| return da.Run(module); |
| } |
| |
| } // namespace tint::resolver |