initial checkin of SkSL compiler

src/sksl/SkSLIRGenerator.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+ 
+#ifndef SKSL_IRGENERATOR
+#define SKSL_IRGENERATOR
+
+#include "SkSLErrorReporter.h"
+#include "ast/SkSLASTBinaryExpression.h"
+#include "ast/SkSLASTBlock.h"
+#include "ast/SkSLASTBreakStatement.h"
+#include "ast/SkSLASTCallSuffix.h"
+#include "ast/SkSLASTContinueStatement.h"
+#include "ast/SkSLASTDiscardStatement.h"
+#include "ast/SkSLASTDoStatement.h"
+#include "ast/SkSLASTExpression.h"
+#include "ast/SkSLASTExpressionStatement.h"
+#include "ast/SkSLASTExtension.h"
+#include "ast/SkSLASTForStatement.h"
+#include "ast/SkSLASTFunction.h"
+#include "ast/SkSLASTIdentifier.h"
+#include "ast/SkSLASTIfStatement.h"
+#include "ast/SkSLASTInterfaceBlock.h"
+#include "ast/SkSLASTModifiers.h"
+#include "ast/SkSLASTPrefixExpression.h"
+#include "ast/SkSLASTReturnStatement.h"
+#include "ast/SkSLASTStatement.h"
+#include "ast/SkSLASTSuffixExpression.h"
+#include "ast/SkSLASTTernaryExpression.h"
+#include "ast/SkSLASTVarDeclaration.h"
+#include "ast/SkSLASTVarDeclarationStatement.h"
+#include "ast/SkSLASTWhileStatement.h"
+#include "ir/SkSLBlock.h"
+#include "ir/SkSLExpression.h"
+#include "ir/SkSLExtension.h"
+#include "ir/SkSLFunctionDefinition.h"
+#include "ir/SkSLInterfaceBlock.h"
+#include "ir/SkSLModifiers.h"
+#include "ir/SkSLSymbolTable.h"
+#include "ir/SkSLStatement.h"
+#include "ir/SkSLType.h"
+#include "ir/SkSLTypeReference.h"
+#include "ir/SkSLVarDeclaration.h"
+
+namespace SkSL {
+
+/**
+ * Performs semantic analysis on an abstract syntax tree (AST) and produces the corresponding 
+ * (unoptimized) intermediate representation (IR).
+ */
+class IRGenerator {
+public:
+    IRGenerator(std::shared_ptr<SymbolTable> root, ErrorReporter& errorReporter);

[dogben, 2016/06/23 15:25:12]

nit: if the caller will hang on to SymbolTable for the lifetime of IRGenerator,
it's probably better to use a raw pointer (or reference if you prefer) instead
of std::shared_ptr.

+
+    std::unique_ptr<VarDeclaration> convertVarDeclaration(ASTVarDeclaration& decl, 

[dogben, 2016/06/23 15:25:12]

nit: document how each method will modify the AST object passed in; or if it
doesn't, make it a const ref. Or maybe pass as std::unique_ptr if the AST object
will not be valid after this call (which would allow the callee to std::move
parts of it).

+                                                          Variable::Storage storage);
+    std::unique_ptr<FunctionDefinition> convertFunction(ASTFunction& f);
+    std::unique_ptr<Statement> convertStatement(ASTStatement& statement);
+    std::unique_ptr<Expression> convertExpression(ASTExpression& expression);
+
+private:
+    void pushSymbolTable();
+    void popSymbolTable();
+
+    std::shared_ptr<Type> convertType(ASTType& type);
+    std::unique_ptr<Expression> call(Position position, 
+                                     std::shared_ptr<FunctionDeclaration> function, 
+                                     std::vector<std::unique_ptr<Expression>> parameters);

[dogben, 2016/06/23 15:25:12]

nit: s/parameters/arguments/, several places in this file, in the context of
calls.

+    bool determineCallCost(std::shared_ptr<FunctionDeclaration> function, 
+                           std::vector<std::unique_ptr<Expression>>& parameters,
+                           int* outCost);
+    std::unique_ptr<Expression> call(Position position, std::unique_ptr<Expression> function, 
+                                     std::vector<std::unique_ptr<Expression>> parameters);
+    std::unique_ptr<Expression> coerce(std::unique_ptr<Expression> expr, 
+                                       std::shared_ptr<Type> type);
+    std::unique_ptr<Block> convertBlock(ASTBlock& block);
+    std::unique_ptr<Statement> convertBreak(ASTBreakStatement& b);
+    std::unique_ptr<Expression> convertConstructor(Position position, 
+                                                   std::shared_ptr<Type> type, 
+                                                   std::vector<std::unique_ptr<Expression>> params);
+    std::unique_ptr<Statement> convertContinue(ASTContinueStatement& c);
+    std::unique_ptr<Statement> convertDiscard(ASTDiscardStatement& d);
+    std::unique_ptr<Statement> convertDo(ASTDoStatement& d);
+    std::unique_ptr<Expression> convertBinaryExpression(ASTBinaryExpression& expression);
+    std::unique_ptr<Extension> convertExtension(ASTExtension& e);
+    std::unique_ptr<Statement> convertExpressionStatement(ASTExpressionStatement& s);
+    std::unique_ptr<Statement> convertFor(ASTForStatement& f);
+    std::unique_ptr<Expression> convertIdentifier(ASTIdentifier& identifier);
+    std::unique_ptr<Statement> convertIf(ASTIfStatement& s);
+    std::unique_ptr<Expression> convertIndex(std::unique_ptr<Expression> base,
+                                             ASTExpression& index);
+    std::unique_ptr<InterfaceBlock> convertInterfaceBlock(ASTInterfaceBlock& s);
+    Modifiers convertModifiers(const ASTModifiers& m);
+    std::unique_ptr<Expression> convertPrefixExpression(ASTPrefixExpression& expression);
+    std::unique_ptr<Statement> convertReturn(ASTReturnStatement& r);
+    std::unique_ptr<Expression> convertSuffixExpression(ASTSuffixExpression& expression);
+    std::unique_ptr<Expression> convertField(std::unique_ptr<Expression> base, std::string field);
+    std::unique_ptr<Expression> convertSwizzle(std::unique_ptr<Expression> base,
+                                               std::string fields);
+    std::unique_ptr<Expression> convertTernaryExpression(ASTTernaryExpression& expression);
+    std::unique_ptr<Statement> convertVarDeclarationStatement(ASTVarDeclarationStatement& s);
+    std::unique_ptr<Statement> convertWhile(ASTWhileStatement& w);
+
+    void markReadFrom(std::shared_ptr<Variable> var);
+    void markWrittenTo(Expression& expr);
+
+    std::shared_ptr<FunctionDeclaration> fCurrentFunction;
+    std::shared_ptr<SymbolTable> fSymbolTable;
+    ErrorReporter& fErrors;
+
+    friend class AutoSymbolTable;
+    friend class Compiler;
+};
+
+}
+
+#endif