/* vim: set ts=4 sw=4 tw=99 et:

  *

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of SourcePawn.

  *

  * SourcePawn is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY

  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * SourcePawn. If not, see http://www.gnu.org/licenses/.

  */

 #include <assert.h>

 #include "../Zone.h"

 #include "../Strings.h"

 #include "../NativeTable.h"

 #include "../TypeManager.h"

 #include "../Modules.h"

 #include "../Code.h"

 #include "SemanticAnalysis.h"

 #include "../Heap-inl.h"

 using namespace ke;

 #define __ emitter_.

 typedef BytecodeEmitter::Label Label;

 class AutoEnterScope

 {

   public:

     AutoEnterScope(Scope **prevp, Scope *scope)

       : prevp_(prevp),

         prev_(*prevp),

         scope_(scope)

     {

         if (!scope_)

             return;

         prev_ = *prevp_;

         *prevp_ = scope;

         assert(prev_ == scope->enclosing());

     }

     ~AutoEnterScope()

     {

         if (scope_)

             *prevp_ = prev_;

     }

   private:

     Scope **prevp_;

     Scope *prev_;

     Scope *scope_;

 };

 SemanticAnalysis::SemanticAnalysis(Zone *zone, CompileContext &cc, TranslationUnit *unit)

   : zone_(zone),

     pool_(zone->pool()),

     cc_(cc),

     unit_(unit),

     hir_(NULL),

     emitter_(pool_),

     module_(NULL),

     loop_(NULL)

 {

 }

 SemanticAnalysis::SemanticAnalysis(SemanticAnalysis *parent, Handle<FunctionType> fun)

   : zone_(parent->zone_),

     pool_(parent->pool_),

     cc_(parent->cc_),

     unit_(parent->unit_),

     hir_(NULL),

     scope_(parent->scope_),

     emitter_(pool_),

     module_(parent->module_),

     fun_(fun),

     loop_(NULL)

 {

 }

 void

 SemanticAnalysis::analyze()

 {

     scope_ = unit_->globalScope();

     module_ = Module::New(zone_);

     for (size_t i = 0; i < unit_->tree()->statements()->length(); i++) {

         Statement *stmt = unit_->tree()->statements()->at(i);

         stmt->accept(this);

     }

     Local<Struct> globals(zone_, unit_->globalScope()->build(zone_));

     if (!globals)

         return;

     module_->setGlobals(globals);

     Local<Code> code(zone_, __ finish());

     if (!code)

         return;

     code->setModule(module_);

     module_->setCode(code);

 #ifndef NDEBUG

 //    Disassemble(code, stdout);

 #endif

     unit_->module_ = module_;

 }

 void

 SemanticAnalysis::visitFunctionStatement(FunctionStatement *stmt)

 {

     FunctionSymbol *sym = stmt->sym();

     Local<FunctionType> type(zone_, sym->type());

     assert(scope_->kind() == Scope::GLOBAL);

     if (stmt->token() == TOK_NATIVE) {

         // Define the native now.

         size_t index;

         if (!zone_->nativeTable()->add(stmt->name(), &index))

             return;

         Local<Native> native(zone_, Native::New(zone_, type, index));

         if (!native)

             return;

         __ object(native);

         __ setglobal(sym);

         __ pop();

     }

     // If the function is a forward or native, we don't have to do anything.

     if (stmt->token() == TOK_NATIVE || stmt->token() == TOK_FORWARD)

         return;

     SemanticAnalysis child(this, type);

     Local<Function> funobj(zone_, child.compile(stmt));

     if (!funobj)

         return;

     __ object(funobj);

     __ setglobal(sym);

     __ public_();

 }

 Function *

 SemanticAnalysis::compile(FunctionStatement *stmt)

 {

     __ setFirstLine(stmt->pos().line);

     AutoEnterScope argScope(&scope_, stmt->argScope());

     AutoEnterScope varScope(&scope_, stmt->varScope());

     stmt->body()->accept(this);

     Local<Code> code(zone_, __ finish());

     if (!code)

         return NULL;

     code->setModule(module_);

     Local<Function> fun(zone_, Function::New(zone_, code, fun_, stmt->name(), stmt->pos()));

     if (!fun)

         return NULL;

 #ifndef NDEBUG

 //    Disassemble(code, stdout);

 #endif

     return fun;

 }

 void 

 SemanticAnalysis::visitBlockStatement(BlockStatement *node)

 {

     AutoEnterScope scope(&scope_, node->scope());

     for (size_t i = 0; i < node->statements()->length(); i++) {

         Statement *stmt = node->statements()->at(i);

         stmt->accept(this);

         assert(__ stackDepth() == 0);

     }

 }

 void

 SemanticAnalysis::visitExpressionStatement(ExpressionStatement *node)

 {

     // While building HIR, we enter new pool and root scopes, since HIR

     // creation is purely temporary.

     PoolScope poolScope(zone_->pool());

     RootScope rootScope(zone_);

     HIR *hir = eval(node->expression());

     if (!hir)

         return;

     discharge(hir);

     __ pop();

 }

 void

 SemanticAnalysis::visitForStatement(ForStatement *node)

 {

     AutoEnterScope scope(&scope_, node->scope());

     PoolScope poolScope(zone_->pool());

     RootScope rootScope(zone_);

     Label join, update;

     LoopScope loop(scope_, &join, &update, &loop_);

     if (node->initialization())

         node->initialization()->accept(this);

     Label header, test;

     if (node->condition())

         __ jump(&test);

     __ bind(&header);

     node->body()->accept(this);

     __ bind(&update);

     if (node->update())

         node->update()->accept(this);

     if (node->condition()) {

         __ bind(&test);

         visitForTest(node->condition(), &header, &join, &join);

     } else {

         __ jump(&header);

     }

     __ bind(&join);

     assert(__ stackDepth() == 0);

 }

 void

 SemanticAnalysis::visitWhileStatement(WhileStatement *node)

 {

     PoolScope poolScope(zone_->pool());

     RootScope rootScope(zone_);

     Label header, join;

     __ bind(&header);

     LoopScope loop(scope_, &join, &header, &loop_);

     if (node->token() == TOK_WHILE) {

         Label body;

         visitForTest(node->condition(), &body, &join, &body);

         node->body()->accept(this);

         __ jump(&header);

     } else {

         node->body()->accept(this);

         visitForTest(node->condition(), &header, &join, &join);

     }

     __ bind(&join);

     assert(__ stackDepth() == 0);

 }

 void

 SemanticAnalysis::visitVariableDeclaration(VariableDeclaration *node)

 {

     PoolScope poolScope(zone_->pool());

     RootScope rootScope(zone_);

     HIR *hir = NULL;

     if (node->initialization()) {

         if ((hir = eval(node->initialization())) == NULL)

             return;

         if ((hir = coerce(hir, node->sym()->type(), Coerce_Assign)) == NULL)

             return;

     } else {

         assert(false);

     }

     discharge(hir);

     if (!__ allocate(node->sym()))

         return;

     set(node->sym());

     __ pop();

 }

 void

 SemanticAnalysis::visitReturnStatement(ReturnStatement *node)

 {

     if (!node->expression()) {

         if (!fun_->returnType()->isVoid()) {

             cc_.reportError(node->pos(), Message_UsedVoidReturn);

             return;

         }

         __ returnvoid();

         return;

     }

     PoolScope poolScope(zone_->pool());

     RootScope rootScope(zone_);

     HIR *hir = eval(node->expression());

     if (!hir)

         return;

     Local<Type> returnType(zone_, fun_->returnType());

     if ((hir = coerce(hir, returnType, Coerce_Return)) == NULL)

         return;

     discharge(hir);

     __ return_();

 }

 void

 SemanticAnalysis::visitBinaryExpression(BinaryExpression *node)

 {

     HIR *left = eval(node->left());

     HIR *right = eval(node->right());

     if (!left || !right)

         return;

     hir_ = binary(node->token(), left, right);

 }

 bool

 SemanticAnalysis::checkArgumentCount(Handle<FunctionType> type, unsigned actual)

 {

     if (type->parameters()->length() == actual)

         return true;

     if (actual > type->parameters()->length()) {

         if (!type->isNative() || !type->isNativeVariadic())

             return false;

         return true;

     }

     if (!type->defaults())

         return false;

     // Missing arguments. See if there's a default argument for each missing

     // actual.

     for (unsigned i = actual; i < type->parameters()->length(); i++) {

         if (!type->defaults()->at(i))

             return false;

     }

     return true;

 }

 void

 SemanticAnalysis::visitNameProxy(NameProxy *proxy)

 {

     Symbol *sym = proxy->sym();

     VariableSymbol *var = sym->asVariable();

     Scope *in = sym->scope();

     switch (in->kind()) {

       case Scope::GLOBAL:

         hir_ = new (pool_) HGlobal(sym);

         return;

       default:

         assert(in->kind() == Scope::BLOCK);

         assert(var->storage() == VariableSymbol::Local);

         hir_ = new (pool_) HLocal(var);

         return;

     }

 }

 void

 SemanticAnalysis::visitIntegerLiteral(IntegerLiteral *lit)

 {

     Local<Type> type(zone_, zone_->types()->getPrimitive(PrimitiveType_Int32));

     hir_ = new (pool_) HInteger(type, lit->value());

 }

 void

 SemanticAnalysis::visitFloatLiteral(FloatLiteral *node)

 {

     Local<Type> type(zone_, zone_->types()->getPrimitive(PrimitiveType_Float));

     hir_ = new (pool_) HFloat(type, (float)node->value());

 }

 void

 SemanticAnalysis::visitCallExpression(CallExpression *node)

 {

     HIR *callee = eval(node->callee());

     if (!callee)

         return;

     if (!callee->type()->isFunction()) {

         cc_.reportError(node->pos(), Message_CalleeNotFunction);

         return;

     }

     Local<FunctionType> fun(zone_, FunctionType::cast(callee->type()));

     if (!checkArgumentCount(fun, node->arguments()->length())) {

         cc_.reportError(node->pos(), Message_ArgumentCountMismatch);

         return;

     }

     if (fun->isForward()) {

         cc_.reportError(node->pos(), Message_ForwardNotImplemented, fun->name()->chars());

         return;

     }

     HIRList *args = new (pool_) HIRList;

     for (unsigned i = 0; i < node->arguments()->length(); i++) {

         Expression *expression = node->arguments()->at(i);

         HIR *arg = eval(expression);

         if (!arg)

             return;

         Handle<Type> given = arg->type();

         bool mustComputeReference;

         if (i >= fun->parameters()->length()) {

             // Special handling for natives. Arguments past the formal must

             // always have references computed. However, arrays are already

             // references for natives.

             assert(fun->isNative() && fun->isNativeVariadic());

             mustComputeReference = !given->isReference() &&

                                    !given->isArray();

         } else {

             Local<Type> actual(zone_, fun->parameterAt(i));

             if (expression->isIndexExpression()) {

                 // Temporarily disabled.

                 assert(!actual->isArray());

                 if (actual->isReference()) {

                     cc_.reportError(expression->pos(), Message_CannotComputeIndexRef);

                     return;

                 }

             }

             // When we start overloading, coercion will have to happen later.

             arg = coerce(arg, actual, Coerce_Arg);

             if (!arg)

                 return;

             mustComputeReference = actual->isReference() && !given->isReference();

         }

         // :TODO: handle mustComputeReference

         assert(!mustComputeReference);

         if (!args->append(arg))

             return;

     }

     hir_ = new (pool_) HCall(fun->returnType(), callee, args);

 }

 void

 SemanticAnalysis::visitAssignment(Assignment *node)

 {

     HLValue *lval = lvalue(node->lvalue());

     if (!lval)

         return;

     HIR *hir = eval(node->expression());

     if ((hir = coerce(hir, lval->type(), Coerce_Assign)) == NULL)

         return;

     hir_ = new (pool_) HStore(lval, hir);

 }

 Type *

 SemanticAnalysis::coercionType(TokenKind token, HIR *left, HIR *right)

 {

     Handle<Type> l = left->type();

     Handle<Type> r = right->type();

     if (token >= TOK_PLUS && token <= TOK_SLASH) {

         // We allow: [float|int32] + [float|int32]

         if (l->isFloat() && r->isInt32())

             return l;

         if (l->isInt32() && r->isFloat())

             return r;

         if (l->isInt32() && r->isInt32())

             return l;

     }

     assert(l == r);

     return left->type();

 }

 HIR *

 SemanticAnalysis::coerce(HIR *hir, Handle<Type> to, CoercionKind kind)

 {

     Handle<Type> from = hir->type();

     if (from->isInt32() && to->isFloat())

         return new (pool_) HConvert(to, OP_CVT_I2F, hir);

     assert(from == to);

     return hir;

 }

 void

 SemanticAnalysis::set(VariableSymbol *sym)

 {

     if (sym->scope()->kind() == Scope::GLOBAL) {

         __ setglobal(sym);

     } else {

         assert(sym->storage() == VariableSymbol::Local);

         __ setlocal(sym);

     }

 }

 HIR *

 SemanticAnalysis::binary(TokenKind token, HIR *left, HIR *right)

 {

     Local<Type> coercion(zone_, coercionType(token, left, right));

     if (!coercion)

         return NULL;

     if ((left = coerce(left, coercion, Coerce_Arg)) == NULL)

         return NULL;

     if ((right = coerce(right, coercion, Coerce_Arg)) == NULL)

         return NULL;

     switch (token) {

      case TOK_PLUS:

       case TOK_MINUS:

       case TOK_STAR:

       case TOK_SLASH:

       case TOK_PERCENT:

       case TOK_AMPERSAND:

       case TOK_BITOR:

       case TOK_BITXOR:

       case TOK_SHR:

       case TOK_USHR:

       case TOK_SHL:

         return new (pool_) HBinary(left->type(), token, left, right);

       case TOK_EQUALS:

       case TOK_NOTEQUALS:

       case TOK_LT:

       case TOK_LE:

       case TOK_GT:

       case TOK_GE:

       case TOK_AND:

       case TOK_OR:

       {

         Local<Type> result(zone_, zone_->types()->getPrimitive(PrimitiveType_Bool));

         return new (pool_) HBinary(result, token, left, right);

       }

       default:

         assert(false);

         return NULL;

     }

 }

 static inline TokenKind

 ToCompare(Expression *expr)

 {

     if (expr->isBinaryExpression()) {

         BinaryExpression *b = expr->toBinaryExpression();

         if (b->token() >= TOK_EQUALS && b->token() <= TOK_OR)

             return b->token();

     } else if (expr->isUnaryExpression()) {

         UnaryExpression *u = expr->toUnaryExpression();

         if (u->token() == TOK_NOT)

             return TOK_NOT;

     }

     return TOK_EOF;

 }

 void

 SemanticAnalysis::visitForTest(Expression *expr,

                                Label *trueBranch,

                                Label *falseBranch,

                                Label *fallthrough)

 {

     TokenKind token = ToCompare(expr);

     if (token == TOK_EOF || token == TOK_NOT) {

         assert(false);

         //visitForUnaryTest(expr, trueBranch, falseBranch, fallthrough);

         return;

     }

     BinaryExpression *bin = expr->toBinaryExpression();

     if (token == TOK_AND || token == TOK_OR) {

         assert(false);

         //visitForLogicTest(expr, trueBranch, falseBranch, fallthrough);

         return;

     }

     HIR *left = eval(bin->left());

     HIR *right = eval(bin->right());

     if (!left || !right)

         return;

     HIR *hir = binary(bin->token(), left, right);

     if (!hir)

         return;

     discharge(hir);

     if (fallthrough == trueBranch)

         __ j(OP_JF, falseBranch);

     else

         __ j(OP_JT, trueBranch);

 }

 HLValue *

 SemanticAnalysis::lvalue(Expression *expr)

 {

     HIR *hir = eval(expr);

     if (!hir)

         return NULL;

     if (!hir->isLValue()) {

         cc_.reportError(expr->pos(), Message_ExpectedLValue);

         return NULL;

     }

     return static_cast<HLValue *>(hir);

 }

 HIR *

 SemanticAnalysis::eval(Expression *expr)

 {

     assert(!hir_);

     expr->accept(this);

     HIR *hir = hir_;

     hir_ = NULL;

     return hir;

 }

 void

 SemanticAnalysis::discharge(HIR *hir)

 {

     EmitHIR(zone_, emitter_, hir);

 }