Add asm.js typer / validator.

src/typing-asm.cc

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/typing-asm.h"
+
+#include "src/ast.h"
+#include "src/codegen.h"
+#include "src/scopes.h"
+#include "src/zone-type-cache.h"
+
+namespace v8 {
+namespace internal {
+namespace {
+
+base::LazyInstance<ZoneTypeCache>::type kCache = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+
+#define FAIL(node, msg)                                                \
+  do {                                                                 \
+    valid_ = false;                                                    \
+    int line = node->position() == RelocInfo::kNoPosition              \
+                   ? -1                                                \
+                   : info_->script()->GetLineNumber(node->position()); \
+    base::OS::SNPrintF(error_message_, sizeof(error_message_),         \
+                       "asm: line %d: %s\n", line + 1, msg);           \
+    return;                                                            \
+  } while (false)
+
+
+#define RECURSE(call)               \
+  do {                              \
+    DCHECK(!HasStackOverflow());    \
+    call;                           \
+    if (HasStackOverflow()) return; \
+    if (!valid_) return;            \
+  } while (false)
+
+
+AsmTyper::AsmTyper(CompilationInfo* info)
+    : info_(info),
+      valid_(true),
+      stdlib_types_(info->zone()),
+      stdlib_heap_types_(info->zone()),
+      stdlib_math_types_(info->zone()),
+      global_variable_type_(HashMap::PointersMatch,
+                            ZoneHashMap::kDefaultHashMapCapacity,
+                            ZoneAllocationPolicy(info->zone())),
+      local_variable_type_(HashMap::PointersMatch,
+                           ZoneHashMap::kDefaultHashMapCapacity,
+                           ZoneAllocationPolicy(info->zone())),
+      in_function_(false),
+      building_function_tables_(false),
+      cache_(kCache.Get()) {
+  InitializeAstVisitor(info->isolate(), info->zone());
+  InitializeStdlib();
+}
+
+
+bool AsmTyper::Validate() {
+  VisitAsmModule(info_->literal());
+  return valid_ && !HasStackOverflow();
+}
+
+
+void AsmTyper::VisitAsmModule(FunctionLiteral* fun) {
+  Scope* scope = fun->scope();
+  if (!scope->is_function_scope()) FAIL(fun, "not at function scope");
+
+  // Module parameters.
+  for (int i = 0; i < scope->num_parameters(); ++i) {
+    Variable* param = scope->parameter(i);
+    DCHECK(GetType(param) == NULL);
+    SetType(param, Type::None(zone()));
+  }
+
+  ZoneList<Declaration*>* decls = scope->declarations();
+
+  // Set all globals to type Any.
+  VariableDeclaration* decl = scope->function();
+  if (decl != NULL) SetType(decl->proxy()->var(), Type::None());
+  RECURSE(VisitDeclarations(scope->declarations()));
+
+  // Validate global variables.
+  RECURSE(VisitStatements(fun->body()));
+
+  // Validate function annotations.
+  for (int i = 0; i < decls->length(); ++i) {
+    FunctionDeclaration* decl = decls->at(i)->AsFunctionDeclaration();
+    if (decl != NULL) {
+      RECURSE(VisitFunctionAnnotation(decl->fun()));
+      Variable* var = decl->proxy()->var();
+      DCHECK(GetType(var) == NULL);
+      SetType(var, computed_type_);
+      DCHECK(GetType(var) != NULL);
+    }
+  }
+
+  // Build function tables.
+  building_function_tables_ = true;
+  RECURSE(VisitStatements(fun->body()));
+  building_function_tables_ = false;
+
+  // Validate function bodies.
+  for (int i = 0; i < decls->length(); ++i) {
+    FunctionDeclaration* decl = decls->at(i)->AsFunctionDeclaration();
+    if (decl != NULL) {
+      RECURSE(
+          VisitWithExpectation(decl->fun(), Type::Any(zone()), "UNREACHABLE"));
+      if (!computed_type_->IsFunction()) {
+        FAIL(decl->fun(), "function literal expected to be a function");
+      }
+    }
+  }
+
+  // Validate exports.
+  ReturnStatement* stmt = fun->body()->last()->AsReturnStatement();
+  RECURSE(VisitWithExpectation(stmt->expression(), Type::Object(),
+                               "expected object export"));
+}
+
+
+void AsmTyper::VisitVariableDeclaration(VariableDeclaration* decl) {
+  Variable* var = decl->proxy()->var();
+  if (var->location() != VariableLocation::PARAMETER) {
+    if (GetType(var) == NULL) {
+      SetType(var, Type::Any(zone()));
+    } else {
+      DCHECK(!GetType(var)->IsFunction());
+    }
+  }
+  DCHECK(GetType(var) != NULL);
+  intish_ = 0;
+}
+
+
+void AsmTyper::VisitFunctionDeclaration(FunctionDeclaration* decl) {
+  if (in_function_) {
+    FAIL(decl, "function declared inside another");
+  }
+}
+
+
+void AsmTyper::VisitFunctionAnnotation(FunctionLiteral* fun) {
+  // Extract result type.
+  ZoneList<Statement*>* body = fun->body();
+  Type* result_type = Type::Undefined(zone());
+  if (body->length() > 0) {
+    ReturnStatement* stmt = body->last()->AsReturnStatement();
+    if (stmt != NULL) {
+      RECURSE(VisitExpressionAnnotation(stmt->expression()));
+      result_type = computed_type_;
+    }
+  }
+  Type::FunctionType* type =
+      Type::Function(result_type, Type::Any(), fun->parameter_count(), zone())
+          ->AsFunction();
+
+  // Extract parameter types.
+  bool good = true;
+  for (int i = 0; i < fun->parameter_count(); ++i) {
+    good = false;
+    if (i >= body->length()) break;
+    ExpressionStatement* stmt = body->at(i)->AsExpressionStatement();
+    if (stmt == NULL) break;
+    Assignment* expr = stmt->expression()->AsAssignment();
+    if (expr == NULL || expr->is_compound()) break;
+    VariableProxy* proxy = expr->target()->AsVariableProxy();
+    if (proxy == NULL) break;
+    Variable* var = proxy->var();
+    if (var->location() != VariableLocation::PARAMETER || var->index() != i)
+      break;
+    RECURSE(VisitExpressionAnnotation(expr->value()));
+    SetType(var, computed_type_);
+    type->InitParameter(i, computed_type_);
+    good = true;
+  }
+  if (!good) FAIL(fun, "missing parameter type annotations");
+
+  SetResult(fun, type);
+}
+
+
+void AsmTyper::VisitExpressionAnnotation(Expression* expr) {
+  // Normal +x or x|0 annotations.
+  BinaryOperation* bin = expr->AsBinaryOperation();
+  if (bin != NULL) {
+    Literal* right = bin->right()->AsLiteral();
+    if (right != NULL) {
+      switch (bin->op()) {
+        case Token::MUL:  // We encode +x as 1*x
+          if (right->raw_value()->ContainsDot() &&
+              right->raw_value()->AsNumber() == 1.0) {
+            SetResult(expr, cache_.kFloat64);
+            return;
+          }
+          break;
+        case Token::BIT_OR:
+          if (!right->raw_value()->ContainsDot() &&
+              right->raw_value()->AsNumber() == 0.0) {
+            SetResult(expr, cache_.kInt32);
+            return;
+          }
+          break;
+        default:
+          break;
+      }
+    }
+    FAIL(expr, "invalid type annotation on binary op");
+  }
+
+  // Numbers or the undefined literal (for empty returns).
+  if (expr->IsLiteral()) {
+    RECURSE(VisitWithExpectation(expr, Type::Any(), "invalid literal"));
+    return;
+  }
+
+  Call* call = expr->AsCall();
+  if (call != NULL) {
+    if (call->expression()->IsVariableProxy()) {
+      RECURSE(VisitWithExpectation(
+          call->expression(), Type::Any(zone()),
+          "only fround allowed on expression annotations"));
+      if (!computed_type_->Is(
+              Type::Function(cache_.kFloat32, Type::Number(zone()), zone()))) {
+        FAIL(call->expression(),
+             "only fround allowed on expression annotations");
+      }
+      if (call->arguments()->length() != 1) {
+        FAIL(call, "invalid argument count calling fround");
+      }
+      SetResult(expr, cache_.kFloat32);
+      return;
+    }
+  }
+
+  FAIL(expr, "invalid type annotation");
+}
+
+
+void AsmTyper::VisitStatements(ZoneList<Statement*>* stmts) {
+  for (int i = 0; i < stmts->length(); ++i) {
+    Statement* stmt = stmts->at(i);
+    RECURSE(Visit(stmt));
+  }
+}
+
+
+void AsmTyper::VisitBlock(Block* stmt) {
+  RECURSE(VisitStatements(stmt->statements()));
+}
+
+
+void AsmTyper::VisitExpressionStatement(ExpressionStatement* stmt) {
+  RECURSE(VisitWithExpectation(stmt->expression(), Type::Any(),
+                               "expression statement expected to be any"));
+}
+
+
+void AsmTyper::VisitEmptyStatement(EmptyStatement* stmt) {}
+
+
+void AsmTyper::VisitEmptyParentheses(EmptyParentheses* expr) { UNREACHABLE(); }
+
+
+void AsmTyper::VisitIfStatement(IfStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "if statement inside module body");
+  }
+  RECURSE(VisitWithExpectation(stmt->condition(), cache_.kInt32,
+                               "if condition expected to be integer"));
+  RECURSE(Visit(stmt->then_statement()));
+  RECURSE(Visit(stmt->else_statement()));
+}
+
+
+void AsmTyper::VisitContinueStatement(ContinueStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "continue statement inside module body");
+  }
+}
+
+
+void AsmTyper::VisitBreakStatement(BreakStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "continue statement inside module body");
+  }
+}
+
+
+void AsmTyper::VisitReturnStatement(ReturnStatement* stmt) {
+  // Handle module return statement in VisitAsmModule.
+  if (!in_function_) {
+    return;
+  }
+  RECURSE(
+      VisitWithExpectation(stmt->expression(), return_type_,
+                           "return expression expected to have return type"));
+}
+
+
+void AsmTyper::VisitWithStatement(WithStatement* stmt) {
+  FAIL(stmt, "bad with statement");
+}
+
+
+void AsmTyper::VisitSwitchStatement(SwitchStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "switch statement inside module body");
+  }
+  RECURSE(VisitWithExpectation(stmt->tag(), cache_.kInt32,
+                               "switch expression non-integer"));
+  ZoneList<CaseClause*>* clauses = stmt->cases();
+  for (int i = 0; i < clauses->length(); ++i) {
+    CaseClause* clause = clauses->at(i);
+    if (clause->is_default()) continue;
+    Expression* label = clause->label();
+    RECURSE(
+        VisitWithExpectation(label, cache_.kInt32, "case label non-integer"));
+    if (!label->IsLiteral()) FAIL(label, "non-literal case label");
+    Handle<Object> value = label->AsLiteral()->value();
+    int32_t value32;
+    if (!value->ToInt32(&value32)) FAIL(label, "illegal case label value");
+    // TODO(bradnelson): Detect duplicates.
+    ZoneList<Statement*>* stmts = clause->statements();
+    RECURSE(VisitStatements(stmts));
+  }
+}
+
+
+void AsmTyper::VisitCaseClause(CaseClause* clause) { UNREACHABLE(); }
+
+
+void AsmTyper::VisitDoWhileStatement(DoWhileStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "do statement inside module body");
+  }
+  RECURSE(Visit(stmt->body()));
+  RECURSE(VisitWithExpectation(stmt->cond(), cache_.kInt32,

[titzer, 2015/08/31 19:16:11]

Is this also true? I thought asm allowed naked conditions like if(a < 3) and do
{x } while (a < 4). It certainly allows do .. while(false)

[bradn, 2015/08/31 19:40:13]

At least not in the text of the spec:

do stmt:Statement while ( expr:Expression ) ;
succeeds if ValidateStatement succeeds for stmt and ValidateExpression succeeds
for expr with a subtype of int.

Same with the others.

do..while(0) would be ok.

+                               "do condition expected to be integer"));
+}
+
+
+void AsmTyper::VisitWhileStatement(WhileStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "while statement inside module body");
+  }
+  RECURSE(VisitWithExpectation(stmt->cond(), cache_.kInt32,
+                               "while condition expected to be integer"));
+  RECURSE(Visit(stmt->body()));
+}
+
+
+void AsmTyper::VisitForStatement(ForStatement* stmt) {
+  if (!in_function_) {
+    FAIL(stmt, "for statement inside module body");
+  }
+  if (stmt->init() != NULL) {
+    RECURSE(Visit(stmt->init()));
+  }
+  if (stmt->cond() != NULL) {
+    RECURSE(VisitWithExpectation(stmt->cond(), cache_.kInt32,

[titzer, 2015/08/31 19:16:11]

Same.

[bradn, 2015/08/31 19:40:13]

See above.

+                                 "for condition expected to be integer"));
+  }
+  if (stmt->next() != NULL) {
+    RECURSE(Visit(stmt->next()));
+  }
+  RECURSE(Visit(stmt->body()));
+}
+
+
+void AsmTyper::VisitForInStatement(ForInStatement* stmt) {
+  FAIL(stmt, "for-in statement encountered");
+}
+
+
+void AsmTyper::VisitForOfStatement(ForOfStatement* stmt) {
+  FAIL(stmt, "for-of statement encountered");
+}
+
+
+void AsmTyper::VisitTryCatchStatement(TryCatchStatement* stmt) {
+  FAIL(stmt, "try statement encountered");
+}
+
+
+void AsmTyper::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
+  FAIL(stmt, "try statement encountered");
+}
+
+
+void AsmTyper::VisitDebuggerStatement(DebuggerStatement* stmt) {
+  FAIL(stmt, "debugger statement encountered");
+}
+
+
+void AsmTyper::VisitFunctionLiteral(FunctionLiteral* expr) {
+  Scope* scope = expr->scope();
+  DCHECK(scope->is_function_scope());
+  if (in_function_) {
+    FAIL(expr, "invalid nested function");
+  }
+
+  if (!expr->bounds().upper->IsFunction()) {
+    FAIL(expr, "invalid function literal");
+  }
+
+  Type::FunctionType* type = expr->bounds().upper->AsFunction();
+  Type* save_return_type = return_type_;
+  return_type_ = type->Result();
+  in_function_ = true;
+  local_variable_type_.Clear();
+  RECURSE(VisitDeclarations(scope->declarations()));
+  RECURSE(VisitStatements(expr->body()));
+  in_function_ = false;
+  return_type_ = save_return_type;
+  IntersectResult(expr, type);
+}
+
+
+void AsmTyper::VisitNativeFunctionLiteral(NativeFunctionLiteral* expr) {
+  FAIL(expr, "function info literal encountered");
+}
+
+
+void AsmTyper::VisitConditional(Conditional* expr) {
+  RECURSE(VisitWithExpectation(expr->condition(), cache_.kInt32,
+                               "condition expected to be integer"));
+  RECURSE(
+      VisitWithExpectation(expr->then_expression(), Type::Number(),
+                           "conditional then branch expected to be integer"));

[titzer, 2015/08/31 19:16:11]

You have number in the expectation and then number in the comment.

Shouldn't conditions use the expectation of the outer expression passed down?

[bradn, 2015/08/31 19:40:13]

The comment is wrong, fixed.
Also, good point about the expected type, using that and updating the message.

+  Type* then_type = computed_type_;
+  RECURSE(
+      VisitWithExpectation(expr->else_expression(), Type::Number(),
+                           "conditional else branch expected to be integer"));
+  Type* else_type = computed_type_;
+  Type* type = Type::Intersect(then_type, else_type, zone());
+  if (!(type->Is(cache_.kInt32) || type->Is(cache_.kFloat64))) {
+    FAIL(expr, "ill-typed conditional");
+  }
+  IntersectResult(expr, type);
+}
+
+
+void AsmTyper::VisitVariableProxy(VariableProxy* expr) {
+  Variable* var = expr->var();
+  if (GetType(var) == NULL) {
+    FAIL(expr, "unbound variable");
+  }
+  Type* type = Type::Intersect(GetType(var), expected_type_, zone());
+  if (type->Is(cache_.kInt32)) {
+    type = cache_.kInt32;
+  }
+  SetType(var, type);
+  intish_ = 0;
+  IntersectResult(expr, type);
+}
+
+
+void AsmTyper::VisitLiteral(Literal* expr) {
+  intish_ = 0;
+  Handle<Object> value = expr->value();
+  if (value->IsNumber()) {
+    int32_t i;
+    uint32_t u;
+    if (expr->raw_value()->ContainsDot()) {
+      IntersectResult(expr, cache_.kFloat64);
+    } else if (value->ToUint32(&u)) {
+      IntersectResult(expr, cache_.kInt32);
+    } else if (value->ToInt32(&i)) {
+      IntersectResult(expr, cache_.kInt32);
+    } else {
+      FAIL(expr, "illegal number");
+    }
+  } else if (value->IsString()) {
+    IntersectResult(expr, Type::String());
+  } else if (value->IsUndefined()) {
+    IntersectResult(expr, Type::Undefined());
+  } else {
+    FAIL(expr, "illegal literal");
+  }
+}
+
+
+void AsmTyper::VisitRegExpLiteral(RegExpLiteral* expr) {
+  FAIL(expr, "regular expression encountered");
+}
+
+
+void AsmTyper::VisitObjectLiteral(ObjectLiteral* expr) {
+  if (in_function_) {
+    FAIL(expr, "object literal in function");
+  }
+  // Allowed for asm module's export declaration.
+  ZoneList<ObjectLiteralProperty*>* props = expr->properties();
+  for (int i = 0; i < props->length(); ++i) {
+    ObjectLiteralProperty* prop = props->at(i);
+    RECURSE(VisitWithExpectation(prop->value(), Type::Any(zone()),
+                                 "object property expected to be a function"));
+    if (!computed_type_->IsFunction()) {
+      FAIL(prop->value(), "non-function in function table");
+    }
+  }
+  IntersectResult(expr, Type::Object(zone()));
+}
+
+
+void AsmTyper::VisitArrayLiteral(ArrayLiteral* expr) {
+  if (in_function_) {
+    FAIL(expr, "array literal inside a function");
+  }
+  // Allowed for function tables.
+  ZoneList<Expression*>* values = expr->values();
+  Type* elem_type = Type::None(zone());
+  for (int i = 0; i < values->length(); ++i) {
+    Expression* value = values->at(i);
+    RECURSE(VisitWithExpectation(value, Type::Any(), "UNREACHABLE"));
+    if (!computed_type_->IsFunction()) {
+      FAIL(value, "array component expected to be a function");
+    }
+    elem_type = Type::Union(elem_type, computed_type_, zone());
+  }
+  array_size_ = values->length();
+  IntersectResult(expr, Type::Array(elem_type, zone()));
+}
+
+
+void AsmTyper::VisitAssignment(Assignment* expr) {
+  // Handle function tables and everything else in different passes.
+  if (!in_function_) {
+    if (expr->value()->IsArrayLiteral()) {
+      if (!building_function_tables_) {
+        return;
+      }
+    } else {
+      if (building_function_tables_) {
+        return;
+      }
+    }
+  }
+  if (expr->is_compound()) FAIL(expr, "compound assignment encountered");
+  Type* type = expected_type_;
+  RECURSE(VisitWithExpectation(
+      expr->value(), type, "assignment value expected to match surrounding"));
+  if (intish_ != 0) {
+    FAIL(expr, "value still an intish");
+  }
+  RECURSE(VisitWithExpectation(expr->target(), computed_type_,
+                               "assignment target expected to match value"));
+  if (intish_ != 0) {
+    FAIL(expr, "value still an intish");
+  }
+  IntersectResult(expr, computed_type_);
+}
+
+
+void AsmTyper::VisitYield(Yield* expr) {
+  FAIL(expr, "yield expression encountered");
+}
+
+
+void AsmTyper::VisitThrow(Throw* expr) {
+  FAIL(expr, "throw statement encountered");
+}
+
+
+int AsmTyper::ElementShiftSize(Type* type) {
+  if (type->Is(cache_.kInt8) || type->Is(cache_.kUint8)) return 0;
+  if (type->Is(cache_.kInt16) || type->Is(cache_.kUint16)) return 1;
+  if (type->Is(cache_.kInt32) || type->Is(cache_.kUint32) ||
+      type->Is(cache_.kFloat32))
+    return 2;
+  if (type->Is(cache_.kFloat64)) return 3;
+  return -1;
+}
+
+
+void AsmTyper::VisitHeapAccess(Property* expr) {
+  Type::ArrayType* array_type = computed_type_->AsArray();
+  size_t size = array_size_;
+  Type* type = array_type->AsArray()->Element();
+  if (type->IsFunction()) {
+    BinaryOperation* bin = expr->key()->AsBinaryOperation();
+    if (bin == NULL || bin->op() != Token::BIT_AND) {
+      FAIL(expr->key(), "expected & in call");
+    }
+    RECURSE(VisitWithExpectation(bin->left(), cache_.kInt32,
+                                 "array index expected to be integer"));
+    Literal* right = bin->right()->AsLiteral();
+    if (right == NULL || right->raw_value()->ContainsDot()) {
+      FAIL(right, "call mask must be integer");
+    }
+    RECURSE(VisitWithExpectation(bin->right(), cache_.kInt32,
+                                 "call mask expected to be integer"));
+    if (static_cast<size_t>(right->raw_value()->AsNumber()) != size - 1) {
+      FAIL(right, "call mask must match function table");
+    }
+    bin->set_bounds(Bounds(cache_.kInt32));
+  } else {
+    BinaryOperation* bin = expr->key()->AsBinaryOperation();
+    if (bin == NULL || bin->op() != Token::SAR) {
+      FAIL(expr->key(), "expected >> in heap access");
+    }
+    RECURSE(VisitWithExpectation(bin->left(), cache_.kInt32,
+                                 "array index expected to be integer"));
+    Literal* right = bin->right()->AsLiteral();
+    if (right == NULL || right->raw_value()->ContainsDot()) {
+      FAIL(right, "heap access shift must be integer");
+    }
+    RECURSE(VisitWithExpectation(bin->right(), cache_.kInt32,
+                                 "array shift expected to be integer"));
+    int n = static_cast<int>(right->raw_value()->AsNumber());
+    int expected_shift = ElementShiftSize(type);
+    if (expected_shift < 0 || n != expected_shift) {
+      FAIL(right, "heap access shift must match element size");
+    }
+    bin->set_bounds(Bounds(cache_.kInt32));
+  }
+  IntersectResult(expr, type);
+}
+
+
+void AsmTyper::VisitProperty(Property* expr) {
+  // stdlib.Math.x
+  Property* inner_prop = expr->obj()->AsProperty();
+  if (inner_prop != NULL) {
+    // Get property name.
+    Literal* key = expr->key()->AsLiteral();
+    if (key == NULL || !key->IsPropertyName())
+      FAIL(expr, "invalid type annotation on property 2");
+    Handle<String> name = key->AsPropertyName();
+
+    // Check that inner property name is "Math".
+    Literal* math_key = inner_prop->key()->AsLiteral();
+    if (math_key == NULL || !math_key->IsPropertyName() ||
+        !math_key->AsPropertyName()->IsUtf8EqualTo(CStrVector("Math")))
+      FAIL(expr, "invalid type annotation on stdlib (a1)");
+
+    // Check that object is stdlib.
+    VariableProxy* proxy = inner_prop->obj()->AsVariableProxy();
+    if (proxy == NULL) FAIL(expr, "invalid type annotation on stdlib (a2)");
+    Variable* var = proxy->var();
+    if (var->location() != VariableLocation::PARAMETER || var->index() != 0)
+      FAIL(expr, "invalid type annotation on stdlib (a3)");
+
+    // Look up library type.
+    Type* type = LibType(stdlib_math_types_, name);
+    if (type == NULL) FAIL(expr, "unknown standard function 3 ");
+    SetResult(expr, type);
+    return;
+  }
+
+  // Only recurse at this point so that we avoid needing
+  // stdlib.Math to have a real type.
+  RECURSE(VisitWithExpectation(expr->obj(), Type::Any(),
+                               "property holder expected to be object"));
+
+  // For heap view or function table access.
+  if (computed_type_->IsArray()) {
+    VisitHeapAccess(expr);
+    return;
+  }
+
+  // Get property name.
+  Literal* key = expr->key()->AsLiteral();
+  if (key == NULL || !key->IsPropertyName())
+    FAIL(expr, "invalid type annotation on property 3");
+  Handle<String> name = key->AsPropertyName();
+
+  // stdlib.x or foreign.x
+  VariableProxy* proxy = expr->obj()->AsVariableProxy();
+  if (proxy != NULL) {
+    Variable* var = proxy->var();
+    if (var->location() != VariableLocation::PARAMETER) {
+      FAIL(expr, "invalid type annotation on variable");
+    }
+    switch (var->index()) {
+      case 0: {
+        // Object is stdlib, look up library type.
+        Type* type = LibType(stdlib_types_, name);
+        if (type == NULL) {
+          FAIL(expr, "unknown standard function 4");
+        }
+        SetResult(expr, type);
+        return;
+      }
+      case 1:
+        // Object is foreign lib.
+        SetResult(expr, expected_type_);
+        return;
+      default:
+        FAIL(expr, "invalid type annotation on parameter");
+    }
+  }
+
+  FAIL(expr, "invalid property access");
+}
+
+
+void AsmTyper::VisitCall(Call* expr) {
+  RECURSE(VisitWithExpectation(expr->expression(), Type::Any(),
+                               "callee expected to be any"));
+  if (computed_type_->IsFunction()) {
+    Type::FunctionType* fun_type = computed_type_->AsFunction();
+    ZoneList<Expression*>* args = expr->arguments();
+    if (fun_type->Arity() != args->length()) {
+      FAIL(expr, "call with wrong arity");
+    }
+    for (int i = 0; i < args->length(); ++i) {
+      Expression* arg = args->at(i);
+      RECURSE(VisitWithExpectation(
+          arg, fun_type->Parameter(i),
+          "call argument expected to match callee parameter"));
+    }
+    IntersectResult(expr, fun_type->Result());
+  } else if (computed_type_->Is(Type::Any())) {
+    // For foreign calls.
+    ZoneList<Expression*>* args = expr->arguments();
+    for (int i = 0; i < args->length(); ++i) {
+      Expression* arg = args->at(i);
+      RECURSE(VisitWithExpectation(arg, Type::Any(),
+                                   "foreign call argument expected to be any"));
+    }
+    IntersectResult(expr, Type::Number());
+  } else {
+    FAIL(expr, "invalid callee");
+  }
+}
+
+
+void AsmTyper::VisitCallNew(CallNew* expr) {
+  if (in_function_) {
+    FAIL(expr, "new not allowed in module function");
+  }
+  RECURSE(VisitWithExpectation(expr->expression(), Type::Any(),
+                               "expected stdlib function"));
+  if (computed_type_->IsFunction()) {
+    Type::FunctionType* fun_type = computed_type_->AsFunction();
+    ZoneList<Expression*>* args = expr->arguments();
+    if (fun_type->Arity() != args->length())
+      FAIL(expr, "call with wrong arity");
+    for (int i = 0; i < args->length(); ++i) {
+      Expression* arg = args->at(i);
+      RECURSE(VisitWithExpectation(
+          arg, fun_type->Parameter(i),
+          "constructor argument expected to match callee parameter"));
+    }
+    IntersectResult(expr, fun_type->Result());
+    return;
+  }
+
+  FAIL(expr, "ill-typed new operator");
+}
+
+
+void AsmTyper::VisitCallRuntime(CallRuntime* expr) {
+  // Allow runtime calls for now.
+}
+
+
+void AsmTyper::VisitUnaryOperation(UnaryOperation* expr) {
+  switch (expr->op()) {
+    case Token::NOT:  // Used to encode != and !==
+      RECURSE(VisitWithExpectation(expr->expression(), cache_.kInt32,
+                                   "operand expected to be integer"));
+      IntersectResult(expr, cache_.kInt32);
+      return;
+    case Token::DELETE:
+      FAIL(expr, "delete operator encountered");
+    case Token::VOID:
+      FAIL(expr, "void operator encountered");
+    case Token::TYPEOF:
+      FAIL(expr, "typeof operator encountered");
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void AsmTyper::VisitCountOperation(CountOperation* expr) {
+  FAIL(expr, "increment or decrement operator encountered");
+}
+
+
+void AsmTyper::VisitBinaryOperation(BinaryOperation* expr) {
+  switch (expr->op()) {
+    case Token::COMMA: {
+      RECURSE(VisitWithExpectation(expr->left(), Type::Any(),
+                                   "left comma operand expected to be any"));
+      RECURSE(VisitWithExpectation(expr->right(), Type::Any(),
+                                   "right comma operand expected to be any"));
+      IntersectResult(expr, computed_type_);
+      return;
+    }
+    case Token::OR:
+    case Token::AND:
+      FAIL(expr, "logical operator encountered");
+    case Token::BIT_OR:
+    case Token::BIT_AND:
+    case Token::BIT_XOR:
+    case Token::SHL:
+    case Token::SHR:
+    case Token::SAR: {
+      // BIT_OR allows Any since it is used as a type coercion.
+      // BIT_XOR allows Number since it is used as a type coercion (encoding ~).
+      Type* expectation =
+          expr->op() == Token::BIT_OR
+              ? Type::Any()
+              : expr->op() == Token::BIT_XOR ? Type::Number() : cache_.kInt32;
+      Type* result =
+          expr->op() == Token::SHR ? Type::Unsigned32() : cache_.kInt32;
+      RECURSE(VisitWithExpectation(expr->left(), expectation,
+                                   "left bit operand expected to be integer"));
+      int left_intish = intish_;
+      RECURSE(VisitWithExpectation(expr->right(), expectation,
+                                   "right bit operand expected to be integer"));
+      int right_intish = intish_;
+      if (left_intish > kMaxUncombinedAdditiveSteps) {
+        FAIL(expr, "too many consecutive additive ops");
+      }
+      if (right_intish > kMaxUncombinedAdditiveSteps) {
+        FAIL(expr, "too many consecutive additive ops");
+      }
+      intish_ = 0;
+      IntersectResult(expr, result);
+      return;
+    }
+    case Token::ADD:
+    case Token::SUB:
+    case Token::MUL:
+    case Token::DIV:
+    case Token::MOD: {
+      RECURSE(VisitWithExpectation(
+          expr->left(), Type::Number(),
+          "left arithmetic operand expected to be number"));
+      Type* left_type = computed_type_;
+      int left_intish = intish_;
+      RECURSE(VisitWithExpectation(
+          expr->right(), Type::Number(),
+          "right arithmetic operand expected to be number"));
+      Type* right_type = computed_type_;
+      int right_intish = intish_;
+      Type* type = Type::Union(left_type, right_type, zone());
+      if (type->Is(cache_.kInt32)) {
+        if (expr->op() == Token::MUL) {
+          if (!expr->left()->IsLiteral() && !expr->right()->IsLiteral()) {
+            FAIL(expr, "direct integer multiply forbidden");
+          }
+          intish_ = 0;
+          IntersectResult(expr, cache_.kInt32);
+          return;
+        } else {
+          intish_ = left_intish + right_intish + 1;
+          if (expr->op() == Token::ADD || expr->op() == Token::SUB) {
+            if (intish_ > kMaxUncombinedAdditiveSteps) {
+              FAIL(expr, "too many consecutive additive ops");
+            }
+          } else {
+            if (intish_ > kMaxUncombinedMultiplicativeSteps) {
+              FAIL(expr, "too many consecutive multiplicative ops");
+            }
+          }
+          IntersectResult(expr, cache_.kInt32);
+          return;
+        }
+      } else if (type->Is(Type::Number())) {
+        IntersectResult(expr, cache_.kFloat64);
+        return;
+      } else {
+        FAIL(expr, "ill-typed arithmetic operation");
+      }
+    }
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void AsmTyper::VisitCompareOperation(CompareOperation* expr) {
+  RECURSE(
+      VisitWithExpectation(expr->left(), Type::Number(),
+                           "left comparison operand expected to be number"));
+  Type* left_type = computed_type_;
+  RECURSE(
+      VisitWithExpectation(expr->right(), Type::Number(),
+                           "right comparison operand expected to be number"));
+  Type* right_type = computed_type_;
+  Type* type = Type::Union(left_type, right_type, zone());
+  expr->set_combined_type(type);
+  if (type->Is(Type::Integral32()) || type->Is(Type::UntaggedFloat64())) {
+    IntersectResult(expr, cache_.kInt32);
+  } else {
+    FAIL(expr, "ill-typed comparison operation");
+  }
+}
+
+
+void AsmTyper::VisitThisFunction(ThisFunction* expr) {
+  FAIL(expr, "this function not allowed");
+}
+
+
+void AsmTyper::VisitDeclarations(ZoneList<Declaration*>* decls) {
+  for (int i = 0; i < decls->length(); ++i) {
+    Declaration* decl = decls->at(i);
+    RECURSE(Visit(decl));
+  }
+}
+
+
+void AsmTyper::VisitImportDeclaration(ImportDeclaration* decl) {
+  FAIL(decl, "import declaration encountered");
+}
+
+
+void AsmTyper::VisitExportDeclaration(ExportDeclaration* decl) {
+  FAIL(decl, "export declaration encountered");
+}
+
+
+void AsmTyper::VisitClassLiteral(ClassLiteral* expr) {
+  FAIL(expr, "class literal not allowed");
+}
+
+
+void AsmTyper::VisitSpread(Spread* expr) { FAIL(expr, "spread not allowed"); }
+
+
+void AsmTyper::VisitSuperPropertyReference(SuperPropertyReference* expr) {
+  FAIL(expr, "super property reference not allowed");
+}
+
+
+void AsmTyper::VisitSuperCallReference(SuperCallReference* expr) {
+  FAIL(expr, "call reference not allowed");
+}
+
+
+void AsmTyper::InitializeStdlib() {
+  Type* number_type = Type::Number(zone());
+  Type* double_type = cache_.kFloat64;
+  Type* double_fn1_type = Type::Function(double_type, double_type, zone());
+  Type* double_fn2_type =
+      Type::Function(double_type, double_type, double_type, zone());
+
+  Type* fround_type = Type::Function(cache_.kFloat32, number_type, zone());
+  Type* imul_type =
+      Type::Function(cache_.kInt32, cache_.kInt32, cache_.kInt32, zone());
+  // TODO(bradnelson): currently only approximating the proper intersection type
+  // (which we cannot currently represent).
+  Type* abs_type = Type::Function(number_type, number_type, zone());
+
+  struct Assignment {
+    const char* name;
+    Type* type;
+  };
+
+  const Assignment math[] = {
+      {"PI", double_type},       {"E", double_type},
+      {"LN2", double_type},      {"LN10", double_type},
+      {"LOG2E", double_type},    {"LOG10E", double_type},
+      {"SQRT2", double_type},    {"SQRT1_2", double_type},
+      {"imul", imul_type},       {"abs", abs_type},
+      {"ceil", double_fn1_type}, {"floor", double_fn1_type},
+      {"fround", fround_type},   {"pow", double_fn2_type},
+      {"exp", double_fn1_type},  {"log", double_fn1_type},
+      {"min", double_fn2_type},  {"max", double_fn2_type},
+      {"sqrt", double_fn1_type}, {"cos", double_fn1_type},
+      {"sin", double_fn1_type},  {"tan", double_fn1_type},
+      {"acos", double_fn1_type}, {"asin", double_fn1_type},
+      {"atan", double_fn1_type}, {"atan2", double_fn2_type}};
+  for (unsigned i = 0; i < arraysize(math); ++i) {
+    stdlib_math_types_[math[i].name] = math[i].type;
+  }
+
+  stdlib_types_["Infinity"] = double_type;
+  stdlib_types_["NaN"] = double_type;
+  Type* buffer_type = Type::Any(zone());
+#define TYPED_ARRAY(TypeName, type_name, TYPE_NAME, ctype, size) \
+  stdlib_types_[#TypeName "Array"] =                             \
+      Type::Function(cache_.k##TypeName##Array, buffer_type, zone());
+  TYPED_ARRAYS(TYPED_ARRAY)
+#undef TYPED_ARRAY
+
+#define TYPED_ARRAY(TypeName, type_name, TYPE_NAME, ctype, size) \
+  stdlib_heap_types_[#TypeName "Array"] =                        \
+      Type::Function(cache_.k##TypeName##Array, buffer_type, zone());
+  TYPED_ARRAYS(TYPED_ARRAY)
+#undef TYPED_ARRAY
+}
+
+
+Type* AsmTyper::LibType(ObjectTypeMap map, Handle<String> name) {
+  base::SmartArrayPointer<char> aname = name->ToCString();
+  ObjectTypeMap::iterator i = map.find(std::string(aname.get()));
+  if (i == map.end()) {
+    return NULL;
+  }
+  return i->second;
+}
+
+
+void AsmTyper::SetType(Variable* variable, Type* type) {
+  ZoneHashMap::Entry* entry;
+  if (in_function_) {
+    entry = local_variable_type_.LookupOrInsert(
+        variable, ComputePointerHash(variable), ZoneAllocationPolicy(zone_));
+  } else {
+    entry = global_variable_type_.LookupOrInsert(
+        variable, ComputePointerHash(variable), ZoneAllocationPolicy(zone_));
+  }
+  entry->value = reinterpret_cast<void*>(type);
+}
+
+
+Type* AsmTyper::GetType(Variable* variable) {
+  i::ZoneHashMap::Entry* entry = NULL;
+  if (in_function_) {
+    entry = local_variable_type_.Lookup(variable, ComputePointerHash(variable));
+  }
+  if (entry == NULL) {
+    entry =
+        global_variable_type_.Lookup(variable, ComputePointerHash(variable));
+  }
+  if (entry == NULL) {
+    return NULL;
+  } else {
+    return reinterpret_cast<Type*>(entry->value);
+  }
+}
+
+
+void AsmTyper::SetResult(Expression* expr, Type* type) {
+  computed_type_ = type;
+  expr->set_bounds(Bounds(computed_type_));
+}
+
+
+void AsmTyper::IntersectResult(Expression* expr, Type* type) {
+  computed_type_ = type;
+  Type* bounded_type = Type::Intersect(computed_type_, expected_type_, zone());
+  expr->set_bounds(Bounds(bounded_type));
+}
+
+
+void AsmTyper::VisitWithExpectation(Expression* expr, Type* expected_type,
+                                    const char* msg) {
+  Type* save = expected_type_;
+  expected_type_ = expected_type;
+  RECURSE(Visit(expr));
+  Type* bounded_type = Type::Intersect(computed_type_, expected_type_, zone());
+  if (bounded_type->Is(Type::None(zone()))) {
+#ifdef DEBUG
+    PrintF("Computed type: ");
+    computed_type_->Print();
+    PrintF("Expected type: ");
+    expected_type_->Print();
+#endif
+    FAIL(expr, msg);
+  }
+  expected_type_ = save;
+}
+}
+}  // namespace v8::internal