[validation] make validator directory

Change-Id: Ia5caea84b48b37f0bee9582ee4c8514da4ee3978
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/31981
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: David Neto <dneto@google.com>

src/validator/validator_impl.h

@@ -0,0 +1,126 @@
+// Copyright 2020 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.
+
+#ifndef SRC_VALIDATOR_VALIDATOR_IMPL_H_
+#define SRC_VALIDATOR_VALIDATOR_IMPL_H_
+
+#include <string>
+#include <unordered_map>
+
+#include "src/ast/assignment_statement.h"
+#include "src/ast/call_expression.h"
+#include "src/ast/expression.h"
+#include "src/ast/identifier_expression.h"
+#include "src/ast/module.h"
+#include "src/ast/return_statement.h"
+#include "src/ast/statement.h"
+#include "src/ast/variable.h"
+#include "src/scope_stack.h"
+
+namespace tint {
+
+/// Determines if the module is complete and valid
+class ValidatorImpl {
+ public:
+  /// Constructor
+  ValidatorImpl();
+  ~ValidatorImpl();
+
+  /// Runs the validator
+  /// @param module the module to validate
+  /// @returns true if the validation was successful
+  bool Validate(const ast::Module* module);
+
+  /// @returns error messages from the validator
+  const std::string& error() { return error_; }
+
+  /// @returns true if an error was encountered
+  bool has_error() const { return error_.size() > 0; }
+
+  /// Sets the error string
+  /// @param src the source causing the error
+  /// @param msg the error message
+  void set_error(const Source& src, const std::string& msg);
+  /// Validate global variables
+  /// @param global_vars list of global variables to check
+  /// @returns true if the validation was successful
+  bool ValidateGlobalVariables(const ast::VariableList& global_vars);
+  /// Validates Functions
+  /// @param funcs the functions to check
+  /// @returns true if the validation was successful
+  bool ValidateFunctions(const ast::FunctionList& funcs);
+  /// Validates a function
+  /// @param func the function to check
+  /// @returns true if the validation was successful
+  bool ValidateFunction(const ast::Function* func);
+  /// Validates a block of statements
+  /// @param block the statements to check
+  /// @returns true if the validation was successful
+  bool ValidateStatements(const ast::BlockStatement* block);
+  /// Validates a statement
+  /// @param stmt the statement to check
+  /// @returns true if the validation was successful
+  bool ValidateStatement(const ast::Statement* stmt);
+  /// Validates an assignment
+  /// @param assign the assignment to check
+  /// @returns true if the validation was successful
+  bool ValidateAssign(const ast::AssignmentStatement* assign);
+  /// Validates an expression
+  /// @param expr the expression to check
+  /// @return true if the expression is valid
+  bool ValidateExpression(const ast::Expression* expr);
+  /// Validates v-0006:Variables must be defined before use
+  /// @param ident the identifer to check if its in the scope
+  /// @return true if idnet was defined
+  bool ValidateIdentifier(const ast::IdentifierExpression* ident);
+  /// Validates if the input follows type checking rules
+  /// @param assign the assignment to check
+  /// @returns ture if successful
+  bool ValidateResultTypes(const ast::AssignmentStatement* assign);
+  /// Validate v-0021: Cannot re-assign a constant
+  /// @param assign is the assigment to check if its lhs is a const
+  /// @returns false if lhs of assign is a constant identifier
+  bool ValidateConstant(const ast::AssignmentStatement* assign);
+  /// Validates declaration name uniquness
+  /// @param decl is the new declartion to be added
+  /// @returns true if no previous decleration with the |decl|'s name
+  /// exist in the variable stack
+  bool ValidateDeclStatement(const ast::VariableDeclStatement* decl);
+  /// Validates return statement
+  /// @param ret the return statement to check
+  /// @returns true if function return type matches the return statement type
+  bool ValidateReturnStatement(const ast::ReturnStatement* ret);
+  /// Validates function calls
+  /// @param expr the call to validate
+  /// @returns true if successful
+  bool ValidateCallExpr(const ast::CallExpression* expr);
+  /// Validates switch statements
+  /// @param s the switch statement to check
+  /// @returns true if the valdiation was successful
+  bool ValidateSwitch(const ast::SwitchStatement* s);
+  /// Validates case statements
+  /// @param c the case statement to check
+  /// @returns true if the valdiation was successful
+  bool ValidateCase(const ast::CaseStatement* c);
+
+ private:
+  std::string error_;
+  ScopeStack<ast::Variable*> variable_stack_;
+  ScopeStack<ast::Function*> function_stack_;
+  ast::Function* current_function_ = nullptr;
+};
+
+}  // namespace tint
+
+#endif  // SRC_VALIDATOR_VALIDATOR_IMPL_H_