One more observation, if I do not keep any argument in my javascript then I
do not see conditional jump. I changed my first javascript to as given
below, with this the conditional jump is not shown in valgrind report.
js1.js
function js_add_elements() { return 10; }
On Thu, Jun 27, 2019 at 6:11 PM Jakob Kummerow <jkumme...@chromium.org>
wrote:
> Could be a bug in valgrind, or a bug in V8. Getting a line number would be
> helpful, along with the exact version of V8. At a quick glance, I don't see
> any uninitialized variables
> in DeclarationScope::CheckConflictingVarDeclarations.
>
> On Thu, Jun 27, 2019 at 2:27 PM Austin Einter <austin.ein...@gmail.com>
> wrote:
>
>> I changed the line to
>> v8::Local<v8::Context> context(instance->context->Get(instance->isolate));
>>
>> It is compiling also working fine.
>>
>> However when I execute this executable with valgrind, I get lot of
>> "*Conditional
>> jump or move depends on uninitialised value(s)*"
>>
>> One such conditional jump is given below.
>>
>> ==5158== Conditional jump or move depends on uninitialised value(s)
>> ==5158== at 0x8F0868:
>> v8::internal::DeclarationScope::CheckConflictingVarDeclarations() (in
>> /home/user/mjse)
>> ==5158== by 0x4D8F68:
>> v8::internal::PreParser::PreParseFunction(v8::internal::AstRawString
>> const*, v8::internal::FunctionKind,
>> v8::internal::FunctionLiteral::FunctionType,
>> v8::internal::DeclarationScope*, int*,
>> v8::internal::ProducedPreparseData**, int) (in /home/user/mjse)
>> ==5158== by 0x4B7935:
>> v8::internal::Parser::SkipFunction(v8::internal::AstRawString const*,
>> v8::internal::FunctionKind, v8::internal::FunctionLiteral::FunctionType,
>> v8::internal::DeclarationScope*, int*, int*,
>> v8::internal::ProducedPreparseData**) (in /home/user/mjse)
>> ==5158== by 0x4AB715:
>> v8::internal::Parser::ParseFunctionLiteral(v8::internal::AstRawString
>> const*, v8::internal::Scanner::Location,
>> v8::internal::FunctionNameValidity, v8::internal::FunctionKind, int,
>> v8::internal::FunctionLiteral::FunctionType, v8::internal::LanguageMode,
>> v8::internal::ZoneList<v8::internal::AstRawString const*>*) (in
>> /home/user/mjse)
>> ==5158== by 0x4D1EFA:
>> v8::internal::ParserBase<v8::internal::Parser>::ParseHoistableDeclaration(int,
>> v8::base::Flags<v8::internal::ParseFunctionFlag, int>,
>> v8::internal::ZoneList<v8::internal::AstRawString const*>*, bool) (in
>> /home/user/mjse)
>> ==5158== by 0x4AA266:
>> v8::internal::Parser::DoParseProgram(v8::internal::Isolate*,
>> v8::internal::ParseInfo*) (in /home/user/mjse)
>> ==5158== by 0x4A9958:
>> v8::internal::Parser::ParseProgram(v8::internal::Isolate*,
>> v8::internal::ParseInfo*) (in /home/user/mjse)
>> ==5158== by 0x4D5759:
>> v8::internal::parsing::ParseProgram(v8::internal::ParseInfo*,
>> v8::internal::Isolate*) (in /home/user/mjse)
>> ==5158== by 0x22A835: v8::internal::(anonymous
>> namespace)::CompileToplevel(v8::internal::ParseInfo*,
>> v8::internal::Isolate*, v8::internal::IsCompiledScope*) (in /home/user/mjse)
>> ==5158== by 0x22C128:
>> v8::internal::Compiler::GetSharedFunctionInfoForScript(v8::internal::Isolate*,
>> v8::internal::Handle<v8::internal::String>,
>> v8::internal::Compiler::ScriptDetails const&, v8::ScriptOriginOptions,
>> v8::Extension*, v8::internal::ScriptData*,
>> v8::ScriptCompiler::CompileOptions, v8::ScriptCompiler::NoCacheReason,
>> v8::internal::NativesFlag) (in /home/user/mjse)
>> ==5158== by 0x1F0EE4:
>> v8::ScriptCompiler::CompileUnboundInternal(v8::Isolate*,
>> v8::ScriptCompiler::Source*, v8::ScriptCompiler::CompileOptions,
>> v8::ScriptCompiler::NoCacheReason) (in /home/user/mjse)
>> ==5158== by 0x1F15D6:
>> v8::ScriptCompiler::Compile(v8::Local<v8::Context>,
>> v8::ScriptCompiler::Source*, v8::ScriptCompiler::CompileOptions,
>> v8::ScriptCompiler::NoCacheReason) (in /home/user/mjse)
>> ==5158==
>>
>>
>> What could be the issue?
>>
>> Thanks
>> Austin
>>
>>
>>
>>
>> On Thu, Jun 27, 2019 at 5:34 PM Austin Einter <austin.ein...@gmail.com>
>> wrote:
>>
>>> Thanks Ben. I followed your suggestion.
>>> I added *v8::Global<v8::Context> *context; *member in instance
>>> structure.
>>>
>>> I put the code as below.
>>>
>>>
>>>
>>>
>>>
>>>
>>> * if(instance->context == nullptr) { v8::Local<v8::Context>
>>> context = v8::Context::New(instance->isolate); instance->context =
>>> new v8::Global<v8::Context>(instance->isolate, context); }*
>>>
>>> * v8::Local<v8::Context> context(instance->isolate,
>>> instance->context);*
>>>
>>> * For last line (in red) I am getting below compilation error.*
>>>
>>> error: no matching function for call to
>>> ‘v8::Local<v8::Context>::Local(v8::Isolate*&, v8::Global<v8::Context>*&)’
>>>
>>> Please let me know what I need to do to avoid this error.
>>>
>>> Thanks
>>> Austin
>>>
>>>
>>> On Thu, Jun 27, 2019 at 2:09 PM Ben Noordhuis <i...@bnoordhuis.nl>
>>> wrote:
>>>
>>>> On Thu, Jun 27, 2019 at 5:05 AM Austin Einter <austin.ein...@gmail.com>
>>>> wrote:
>>>> >
>>>> > Dear All
>>>> > I am quite new to v8. I am a c developer, with limited c++ knowledge.
>>>> Sorry if I ask very basic questions.
>>>> >
>>>> > I have a C application, that interacts with web servers. Gets
>>>> javascript. Need to execute javascript.
>>>> > Imagine a situation, where I get total 2 javascript files from server.
>>>> >
>>>> > js1.js
>>>> >
>>>> > function js_add_elements(var1, var2)
>>>> > {
>>>> > var var3 = parseInt(var1) + parseInt(var2);
>>>> > var result = 'Addition of ' + var1 + ' and ' + var2 + ' results '
>>>> + var3;
>>>> > return result;
>>>> > }
>>>> >
>>>> >
>>>> > js2.js
>>>> >
>>>> > js_add_elements(2, 3);
>>>> >
>>>> >
>>>> >
>>>> > I have my c code as below.
>>>> >
>>>> > Header file
>>>> > typedef struct
>>>> > {
>>>> > std::unique_ptr<v8::Platform> platform;
>>>> > v8::Isolate::CreateParams create_params;
>>>> > v8::Isolate *isolate;
>>>> > v8::Isolate::Scope *isolate_scope;
>>>> > }MJSEInstance;
>>>> >
>>>> > #ifdef __cplusplus
>>>> > extern "C" {
>>>> > #endif
>>>> >
>>>> > /**
>>>> > * @brief Create MJSE instance
>>>> > */
>>>> > void *mjse_create_instance(char **argv);
>>>> >
>>>> > /**
>>>> > * @brief Destroy MJSE instance
>>>> > * @param instance -> MJSE instance
>>>> > */
>>>> > void mjse_destroy_instance(void *instance);
>>>> >
>>>> > /**
>>>> > * @brief Executes a script
>>>> > * @param minstance - MJSE instance
>>>> > * @param jscript - the javascript
>>>> > * @param scriptlen - Length of script
>>>> > */
>>>> > void mjse_execute_script(void *instance, char *jscript);
>>>> >
>>>> > #ifdef __cplusplus
>>>> > }
>>>> > #endif
>>>> >
>>>> > CPP File
>>>> > #include <stdio.h>
>>>> > #include <stdlib.h>
>>>> > #include <string.h>
>>>> > #include "include/libplatform/libplatform.h"
>>>> > #include "include/v8.h"
>>>> > #include "mjse.h"
>>>> > #include "mjse_int.h"
>>>> > #include <new>
>>>> >
>>>> > extern "C" {
>>>> > using namespace v8;
>>>> >
>>>> > void *mjse_create_instance(char **argv)
>>>> > {
>>>> > MJSEInstance *instance = (MJSEInstance *)calloc(1,
>>>> sizeof(MJSEInstance));
>>>> >
>>>> > v8::V8::InitializeICUDefaultLocation(argv[0]);
>>>> > v8::V8::InitializeExternalStartupData(argv[0]);
>>>> > instance->platform = v8::platform::NewDefaultPlatform();
>>>> >
>>>> > v8::V8::InitializePlatform(instance->platform.get());
>>>> > v8::V8::Initialize();
>>>> >
>>>> > instance->create_params.array_buffer_allocator =
>>>> v8::ArrayBuffer::Allocator::NewDefaultAllocator();
>>>> > instance->isolate = v8::Isolate::New(instance->create_params);
>>>> > instance->isolate_scope = new
>>>> v8::Isolate::Scope(instance->isolate);
>>>> >
>>>> > return instance;
>>>> > }
>>>> >
>>>> > void mjse_destroy_instance(void *minstance)
>>>> > {
>>>> > MJSEInstance *instance = (MJSEInstance *)minstance;
>>>> >
>>>> > if(instance == NULL)
>>>> > return;
>>>> >
>>>> > if(instance->isolate_scope)
>>>> > {
>>>> > delete instance->isolate_scope;
>>>> > }
>>>> >
>>>> > if(instance->isolate)
>>>> > {
>>>> > instance->isolate->Dispose();
>>>> > }
>>>> >
>>>> > v8::V8::Dispose();
>>>> > v8::V8::ShutdownPlatform();
>>>> >
>>>> > if(instance->create_params.array_buffer_allocator)
>>>> > {
>>>> > delete instance->create_params.array_buffer_allocator;
>>>> > }
>>>> >
>>>> > instance->~MJSEInstance();
>>>> > free(instance);
>>>> > }
>>>> >
>>>> >
>>>> > void mjse_execute_script(void *minstance, char *jscript)
>>>> > {
>>>> > MJSEInstance *instance = (MJSEInstance *)minstance;
>>>> >
>>>> > // Create a stack-allocated handle scope.
>>>> > v8::HandleScope handle_scope(instance->isolate);
>>>> >
>>>> > // Create a new context.
>>>> > v8::Local<v8::Context> context =
>>>> v8::Context::New(instance->isolate);
>>>> >
>>>> > // Enter the context for compiling and running the hello world
>>>> script.
>>>> > v8::Context::Scope context_scope(context);
>>>> >
>>>> > {
>>>> >
>>>> > // Create a string containing the JavaScript source code.
>>>> > v8::Local<v8::String> source =
>>>> > v8::String::NewFromUtf8(instance->isolate, jscript,
>>>> > v8::NewStringType::kNormal).ToLocalChecked();
>>>> >
>>>> > // Compile the source code.
>>>> > v8::Local<v8::Script> script =
>>>> > v8::Script::Compile(context, source).ToLocalChecked();
>>>> >
>>>> > // Run the script to get the result.
>>>> > v8::Local<v8::Value> result =
>>>> script->Run(context).ToLocalChecked();
>>>> >
>>>> > // Convert the result to an UTF8 string and print it.
>>>> > v8::String::Utf8Value utf8(instance->isolate, result);
>>>> > printf("%s\n", *utf8);
>>>> > }
>>>> > }
>>>> > }
>>>> >
>>>> > Main File
>>>> > int main(int argc, char **argv)
>>>> > {
>>>> > char *script;
>>>> > void *instance;
>>>> >
>>>> > instance = mjse_create_instance(argv);
>>>> >
>>>> > script = "function js_add_elements(var1, var2) \
>>>> > { \
>>>> > var var3 = parseInt(var1) + parseInt(var2); \
>>>> > var result = 'Addition of ' + var1 + ' and ' +
>>>> var2 + ' results ' + var3; \
>>>> > return result; \
>>>> > };";
>>>> > mjse_execute_script(instance, script);
>>>> >
>>>> > script = "js_add_elements(2, 3);";
>>>> > mjse_execute_script(instance, script);
>>>> >
>>>> > mjse_destroy_instance(instance);
>>>> > return 0;
>>>> > }
>>>> >
>>>> > Now whats happening, while executing javascript first time it
>>>> executes fine. But while trying to execute second time (letter in red), it
>>>> gets exception.
>>>> >
>>>> > I understand, it is creating new v8 Local context each time, and does
>>>> not have js1.js details, hence getting exception. I also found in web we
>>>> can have v8 Global context and refer the context while executing for second
>>>> time.
>>>> >
>>>> > However I have not been able to find, how to declare v8 global
>>>> context and store / move v8 local context there and refer it during second
>>>> time execution. Please let me know with a sample/example code.
>>>> >
>>>> > Thanks
>>>> > Austin
>>>>
>>>> You can make the context persistent like this:
>>>>
>>>> if (instance->context == nullptr) {
>>>> v8::Local<v8::Context> context =
>>>> v8::Context::New(instance->isolate);
>>>> instance->context = new v8::Global<v8::Context>(instance->isolate,
>>>> context);
>>>> }
>>>>
>>>> v8::Local<v8::Context> context(instance->isolate, instance->context);
>>>> v8::Context::Scope context_scope(context);
>>>>
>>>> --
>>>> --
>>>> v8-users mailing list
>>>> v8-users@googlegroups.com
>>>> http://groups.google.com/group/v8-users
>>>> ---
>>>> You received this message because you are subscribed to the Google
>>>> Groups "v8-users" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to v8-users+unsubscr...@googlegroups.com.
>>>> To view this discussion on the web visit
>>>> https://groups.google.com/d/msgid/v8-users/CAHQurc8H1d8Stfhw7rAGac9ZSL3pS5mOmrR-9%3DjGLtW2ZtMunQ%40mail.gmail.com
>>>> .
>>>> For more options, visit https://groups.google.com/d/optout.
>>>>
>>> --
>> --
>> v8-users mailing list
>> v8-users@googlegroups.com
>> http://groups.google.com/group/v8-users
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "v8-users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to v8-users+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/v8-users/CANXt1k_oVrTPsa6US7Ux6Q25ut%2B-jiF5XD9swpgQKHJPcVG21Q%40mail.gmail.com
>> <https://groups.google.com/d/msgid/v8-users/CANXt1k_oVrTPsa6US7Ux6Q25ut%2B-jiF5XD9swpgQKHJPcVG21Q%40mail.gmail.com?utm_medium=email&utm_source=footer>
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
> --
> --
> v8-users mailing list
> v8-users@googlegroups.com
> http://groups.google.com/group/v8-users
> ---
> You received this message because you are subscribed to the Google Groups
> "v8-users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to v8-users+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/v8-users/CAKSzg3SmJ0xBcw_dy2Ec3VDRhv%3DeoYM%3D6rN8uhAKqCfO5Y-A_A%40mail.gmail.com
> <https://groups.google.com/d/msgid/v8-users/CAKSzg3SmJ0xBcw_dy2Ec3VDRhv%3DeoYM%3D6rN8uhAKqCfO5Y-A_A%40mail.gmail.com?utm_medium=email&utm_source=footer>
> .
> For more options, visit https://groups.google.com/d/optout.
>
--
--
v8-users mailing list
v8-users@googlegroups.com
http://groups.google.com/group/v8-users
---
You received this message because you are subscribed to the Google Groups
"v8-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to v8-users+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/v8-users/CANXt1k8xm4VXArgBic2hybgAE%3DHGumaSLwODfT%2B_kKMBFkDKyQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
