initial checkin of SkSL compiler

src/sksl/ir/SkSLSymbolTable.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+ #include "SkSLSymbolTable.h"
+
+namespace SkSL {
+
+std::vector<std::shared_ptr<FunctionDeclaration>> SymbolTable::GetFunctions(
+                                                                 const std::shared_ptr<Symbol>& s) {
+    switch (s->fKind) {
+        case Symbol::kFunctionDeclaration_Kind:
+            return { std::static_pointer_cast<FunctionDeclaration>(s) };
+        case Symbol::kUnresolvedFunction_Kind:
+            return ((UnresolvedFunction&) *s).fFunctions;
+        default:
+            return { };
+    }
+}
+
+std::shared_ptr<Symbol> SymbolTable::operator[](const std::string& name) {
+    const auto& entry = fSymbols.find(name);
+    if (entry == fSymbols.end()) {
+        if (fParent) {
+            return (*fParent)[name];
+        }
+        return nullptr;
+    }
+    if (fParent) {
+        auto functions = GetFunctions(entry->second);
+        if (functions.size() > 0) {
+            bool modified = false;
+            std::shared_ptr<Symbol> previous = (*fParent)[name];
+            if (previous) {
+                auto previousFunctions = GetFunctions(previous);
+                for (const std::shared_ptr<FunctionDeclaration>& prev : previousFunctions) {
+                    bool found = false;
+                    for (const std::shared_ptr<FunctionDeclaration>& current : functions) {
+                        if (current->matches(*prev)) {
+                            found = true;
+                            break;
+                        }
+                    }
+                    if (!found) {
+                        functions.push_back(prev);
+                        modified = true;
+                    }
+                }
+                if (modified) {
+                    ASSERT(functions.size() > 1);
+                    return std::shared_ptr<Symbol>(new UnresolvedFunction(functions));
+                }
+            }
+        }
+    }
+    return entry->second;
+}
+
+void SymbolTable::add(const std::string& name, std::shared_ptr<Symbol> symbol) {
+        const auto& existing = fSymbols.find(name);
+        if (existing == fSymbols.end()) {
+            fSymbols[name] = symbol;
+        } else if (symbol->fKind == Symbol::kFunctionDeclaration_Kind) {
+            const std::shared_ptr<Symbol>& oldSymbol = existing->second;
+            if (oldSymbol->fKind == Symbol::kFunctionDeclaration_Kind) {
+                std::vector<std::shared_ptr<FunctionDeclaration>> functions;
+                functions.push_back(std::static_pointer_cast<FunctionDeclaration>(oldSymbol));
+                functions.push_back(std::static_pointer_cast<FunctionDeclaration>(symbol));
+                fSymbols[name].reset(new UnresolvedFunction(std::move(functions)));
+            } else if (oldSymbol->fKind == Symbol::kUnresolvedFunction_Kind) {
+                std::vector<std::shared_ptr<FunctionDeclaration>> functions;
+                for (const auto& f : ((UnresolvedFunction&) *oldSymbol).fFunctions) {
+                    functions.push_back(f);
+                }
+                functions.push_back(std::static_pointer_cast<FunctionDeclaration>(symbol));
+                fSymbols[name].reset(new UnresolvedFunction(std::move(functions)));
+            }
+        } else {
+            fErrorReporter.error(symbol->fPosition, "symbol '" + name + "' was already defined");
+        }
+    }
+} // namespace