CSE2410 Fall 2014 Bounce

// Copyright 2009 the V8 project authors. All rights reserved.

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

//       copyright notice, this list of conditions and the following

//       disclaimer in the documentation and/or other materials provided

//       with the distribution.

//     * Neither the name of Google Inc. nor the names of its

//       contributors may be used to endorse or promote products derived

//       from this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#include "bootstrapper.h"

#include "codegen-inl.h"

#include "compilation-cache.h"

#include "compiler.h"

#include "debug.h"

#include "oprofile-agent.h"

#include "rewriter.h"

#include "scopes.h"

#include "usage-analyzer.h"

namespace v8 { namespace internal {

static Handle<Code> MakeCode(FunctionLiteral* literal,

                             Handle<Script> script,

                             Handle<Context> context,

                             bool is_eval) {

  ASSERT(literal != NULL);

  // Rewrite the AST by introducing .result assignments where needed.

  if (!Rewriter::Process(literal) || !AnalyzeVariableUsage(literal)) {

    // Signal a stack overflow by returning a null handle.  The stack

    // overflow exception will be thrown by the caller.

    return Handle<Code>::null();

  }

  // Compute top scope and allocate variables. For lazy compilation

  // the top scope only contains the single lazily compiled function,

  // so this doesn't re-allocate variables repeatedly.

  Scope* top = literal->scope();

  while (top->outer_scope() != NULL) top = top->outer_scope();

  top->AllocateVariables(context);

#ifdef DEBUG

  if (Bootstrapper::IsActive() ?

      FLAG_print_builtin_scopes :

      FLAG_print_scopes) {

    literal->scope()->Print();

  }

#endif

  // Optimize the AST.

  if (!Rewriter::Optimize(literal)) {

    // Signal a stack overflow by returning a null handle.  The stack

    // overflow exception will be thrown by the caller.

    return Handle<Code>::null();

  }

  // Generate code and return it.

  Handle<Code> result = CodeGenerator::MakeCode(literal, script, is_eval);

  return result;

}

static Handle<JSFunction> MakeFunction(bool is_global,

                                       bool is_eval,

                                       Handle<Script> script,

                                       Handle<Context> context,

                                       v8::Extension* extension,

                                       ScriptDataImpl* pre_data) {

  ZoneScope zone_scope(DELETE_ON_EXIT);

  // Make sure we have an initial stack limit.

  StackGuard guard;

  PostponeInterruptsScope postpone;

  // Notify debugger

  Debugger::OnBeforeCompile(script);

  // Only allow non-global compiles for eval.

  ASSERT(is_eval || is_global);

  // Build AST.

  FunctionLiteral* lit = MakeAST(is_global, script, extension, pre_data);

  // Check for parse errors.

  if (lit == NULL) {

    ASSERT(Top::has_pending_exception());

    return Handle<JSFunction>::null();

  }

  // Measure how long it takes to do the compilation; only take the

  // rest of the function into account to avoid overlap with the

  // parsing statistics.

  HistogramTimer* rate = is_eval

      ? &Counters::compile_eval

      : &Counters::compile;

  HistogramTimerScope timer(rate);

  // Compile the code.

  Handle<Code> code = MakeCode(lit, script, context, is_eval);

  // Check for stack-overflow exceptions.

  if (code.is_null()) {

    Top::StackOverflow();

    return Handle<JSFunction>::null();

  }

#if defined ENABLE_LOGGING_AND_PROFILING || defined ENABLE_OPROFILE_AGENT

  // Log the code generation for the script. Check explicit whether logging is

  // to avoid allocating when not required.

  if (Logger::is_enabled() || OProfileAgent::is_enabled()) {

    if (script->name()->IsString()) {

      SmartPointer<char> data =

          String::cast(script->name())->ToCString(DISALLOW_NULLS);

      LOG(CodeCreateEvent(is_eval ? "Eval" : "Script", *code, *data));

      OProfileAgent::CreateNativeCodeRegion(*data, code->address(),

                                            code->ExecutableSize());

    } else {

      LOG(CodeCreateEvent(is_eval ? "Eval" : "Script", *code, ""));

      OProfileAgent::CreateNativeCodeRegion(is_eval ? "Eval" : "Script",

          code->address(), code->ExecutableSize());

    }

  }

#endif

  // Allocate function.

  Handle<JSFunction> fun =

      Factory::NewFunctionBoilerplate(lit->name(),

                                      lit->materialized_literal_count(),

                                      lit->contains_array_literal(),

                                      code);

  CodeGenerator::SetFunctionInfo(fun, lit->scope()->num_parameters(),

                                 RelocInfo::kNoPosition,

                                 lit->start_position(), lit->end_position(),

                                 lit->is_expression(), true, script,

                                 lit->inferred_name());

  // Hint to the runtime system used when allocating space for initial

  // property space by setting the expected number of properties for

  // the instances of the function.

  SetExpectedNofPropertiesFromEstimate(fun, lit->expected_property_count());

  // Notify debugger

  Debugger::OnAfterCompile(script, fun);

  return fun;

}

static StaticResource<SafeStringInputBuffer> safe_string_input_buffer;

Handle<JSFunction> Compiler::Compile(Handle<String> source,

                                     Handle<Object> script_name,

                                     int line_offset, int column_offset,

                                     v8::Extension* extension,

                                     ScriptDataImpl* input_pre_data) {

  int source_length = source->length();

  Counters::total_load_size.Increment(source_length);

  Counters::total_compile_size.Increment(source_length);

  // The VM is in the COMPILER state until exiting this function.

  VMState state(COMPILER);

  // Do a lookup in the compilation cache but not for extensions.

  Handle<JSFunction> result;

  if (extension == NULL) {

    result = CompilationCache::LookupScript(source,

                                            script_name,

                                            line_offset,

                                            column_offset);

  }

  if (result.is_null()) {

    // No cache entry found. Do pre-parsing and compile the script.

    ScriptDataImpl* pre_data = input_pre_data;

    if (pre_data == NULL && source_length >= FLAG_min_preparse_length) {

      Access<SafeStringInputBuffer> buf(&safe_string_input_buffer);

      buf->Reset(source.location());

      pre_data = PreParse(buf.value(), extension);

    }

    // Create a script object describing the script to be compiled.

    Handle<Script> script = Factory::NewScript(source);

    if (!script_name.is_null()) {

      script->set_name(*script_name);

      script->set_line_offset(Smi::FromInt(line_offset));

      script->set_column_offset(Smi::FromInt(column_offset));

    }

    // Compile the function and add it to the cache.

    result = MakeFunction(true,

                          false,

                          script,

                          Handle<Context>::null(),

                          extension,

                          pre_data);

    if (extension == NULL && !result.is_null()) {

      CompilationCache::PutScript(source, result);

    }

    // Get rid of the pre-parsing data (if necessary).

    if (input_pre_data == NULL && pre_data != NULL) {

      delete pre_data;

    }

  }

  if (result.is_null()) Top::ReportPendingMessages();

  return result;

}

Handle<JSFunction> Compiler::CompileEval(Handle<String> source,

                                         Handle<Context> context,

                                         int line_offset,

                                         bool is_global) {

  int source_length = source->length();

  Counters::total_eval_size.Increment(source_length);

  Counters::total_compile_size.Increment(source_length);

  // The VM is in the COMPILER state until exiting this function.

  VMState state(COMPILER);

  CompilationCache::Entry entry = is_global

      ? CompilationCache::EVAL_GLOBAL

      : CompilationCache::EVAL_CONTEXTUAL;

  // Do a lookup in the compilation cache; if the entry is not there,

  // invoke the compiler and add the result to the cache.

  Handle<JSFunction> result =

      CompilationCache::LookupEval(source, context, entry);

  if (result.is_null()) {

    // Create a script object describing the script to be compiled.

    Handle<Script> script = Factory::NewScript(source);

    script->set_line_offset(Smi::FromInt(line_offset));

    result = MakeFunction(is_global, true, script, context, NULL, NULL);

    if (!result.is_null()) {

      CompilationCache::PutEval(source, context, entry, result);

    }

  }

  return result;

}

bool Compiler::CompileLazy(Handle<SharedFunctionInfo> shared,

                           int loop_nesting) {

  ZoneScope zone_scope(DELETE_ON_EXIT);

  // The VM is in the COMPILER state until exiting this function.

  VMState state(COMPILER);

  // Make sure we have an initial stack limit.

  StackGuard guard;

  PostponeInterruptsScope postpone;

  // Compute name, source code and script data.

  Handle<String> name(String::cast(shared->name()));

  Handle<Script> script(Script::cast(shared->script()));

  int start_position = shared->start_position();

  int end_position = shared->end_position();

  bool is_expression = shared->is_expression();

  Counters::total_compile_size.Increment(end_position - start_position);

  // Generate the AST for the lazily compiled function. The AST may be

  // NULL in case of parser stack overflow.

  FunctionLiteral* lit = MakeLazyAST(script, name,

                                     start_position,

                                     end_position,

                                     is_expression);

  // Check for parse errors.

  if (lit == NULL) {

    ASSERT(Top::has_pending_exception());

    return false;

  }

  // Update the loop nesting in the function literal.

  lit->set_loop_nesting(loop_nesting);

  // Measure how long it takes to do the lazy compilation; only take

  // the rest of the function into account to avoid overlap with the

  // lazy parsing statistics.

  HistogramTimerScope timer(&Counters::compile_lazy);

  // Compile the code.

  Handle<Code> code = MakeCode(lit, script, Handle<Context>::null(), false);

  // Check for stack-overflow exception.

  if (code.is_null()) {

    Top::StackOverflow();

    return false;

  }

#if defined ENABLE_LOGGING_AND_PROFILING || defined ENABLE_OPROFILE_AGENT

  // Log the code generation. If source information is available include script

  // name and line number. Check explicit whether logging is enabled as finding

  // the line number is not for free.

  if (Logger::is_enabled() || OProfileAgent::is_enabled()) {

    Handle<String> func_name(lit->name()->length() > 0 ?

                             *lit->name() : shared->inferred_name());

    if (script->name()->IsString()) {

      int line_num = GetScriptLineNumber(script, start_position);

      if (line_num > 0) {

        line_num += script->line_offset()->value() + 1;

      }

      LOG(CodeCreateEvent("LazyCompile", *code, *func_name,

                          String::cast(script->name()), line_num));

      OProfileAgent::CreateNativeCodeRegion(*func_name,

                                            String::cast(script->name()),

                                            line_num, code->address(),

                                            code->ExecutableSize());

    } else {

      LOG(CodeCreateEvent("LazyCompile", *code, *func_name));

      OProfileAgent::CreateNativeCodeRegion(*func_name, code->address(),

                                            code->ExecutableSize());

    }

  }

#endif

  // Update the shared function info with the compiled code.

  shared->set_code(*code);

  // Set the expected number of properties for instances.

  SetExpectedNofPropertiesFromEstimate(shared, lit->expected_property_count());

  // Check the function has compiled code.

  ASSERT(shared->is_compiled());

  return true;

}

} }  // namespace v8::internal