[cfe-dev] Need Help in resolving exception while calling FunctionDecl Method

[Apoorva Paneliya via cfe-dev]

Hi Aleksei,

I had put break point on ASTContext Destructor but somehow, it was not
hitting.

After that, I looked at the clang-query code and got a clue. [*Just Build
AST*]

CommonOptionsParser OptionsParser(argc, argv, ToolingSampleCategory);
ClangTool tool(OptionsParser.getCompilations(),
OptionsParser.getSourcePathList());

std::vector<std::unique_ptr<ASTUnit>> ASTs;
* if (tool.buildASTs(ASTs) == 0)*
{
cout << "successfully generated AST " << std::endl;
}
else
{
cout << "Failed to Generate AST " << std::endl;
return -1;
}

Thank you very much for giving suggestion.


On Wed, Dec 28, 2016 at 2:57 PM, Aleksei Sidorin <a.sidorin at samsung.com>
wrote:

> Another suggestion is that ASTContext that is used for running your tool
> dies before Tool.run() is executed.
>
> In FrontendActionFactory::runInvocation a CompilerInstance is created. It
> has a smart pointer to the created ASTContext. But the CompilerInstance is
> a local variable and it is destroyed within all its data after invocation
> ends.
> You can try to set a breakpoint on the ASTContext destructor and see the
> moment where it is destructed and the stack trace.
>
>
>
> 27.12.2016 22:49, Apoorva Paneliya пишет:
>
> Hi Aleksei,
>
> I tried your below suggestion.
>
> std::unique_ptr<FrontendActionFactory> Factory =
>       newFrontendActionFactory(&funcHelper.MatchFinder);
> Tool.run(Factory.get());
>
> unfortunately, result is same (still, exception is generated).
>
> It is also a good idea to check that your vector is non-empty before
> getting an element. -> *Implemented.*
>
> Let me know if you have any other suggestion.
>
> thank you very much.!!
>
>
>
> On Wed, Dec 28, 2016 at 12:06 AM, Aleksei Sidorin <a.sidorin at samsung.com>
> wrote:
>
>> > Tool.run(newFrontendActionFactory(&(funcHelper.MatchFinder)).get());
>>
>> As I can guess, newFrontendActionFactory() returns std::unique_ptr which
>> is destructed immediately after this statement is executed. So, it seems
>> like you have a memory use-after-free. Try this instead:
>>
>> std::unique_ptr<FrontendActionFactory> Factory =
>>       newFrontendActionFactory(&funcHelper.MatchFinder);
>> Tool.run(Factory.get());
>>
>> Does it help?
>>
>> It is also a good idea to check that your vector is non-empty before
>> getting an element.
>>
>>
>>
>> 27.12.2016 17:57, Apoorva Paneliya via cfe-dev пишет:
>>
>> Hi there,
>>
>> Just now started with Clang. so, this might silly question.
>>
>> I am getting exception while calling *FunctionDecl->getNameAsString() or
>>  **FunctionDecl->**getName().str()*;
>>
>> Exception Details:-
>>
>> Type:-  "Exception thrown: read access violation."
>>
>> Points to:-
>>
>> File:- include\clang\AST\DeclarationNames.h
>>
>> *StoredNameKind getStoredNameKind() const {*
>> *    return static_cast<StoredNameKind>(Ptr & PtrMask);*
>> *  }*
>>
>> Actual Code
>>
>> *Main.cpp*
>>
>> static llvm::cl::OptionCategory ToolingSampleCategory("Tooling Sample");
>>
>> int main(int argc, const char **argv)
>> {
>>
>>         CommonOptionsParser OptionsParser(argc, argv,
>> ToolingSampleCategory);
>> ClangTool Tool(OptionsParser.getCompilations(),
>> OptionsParser.getSourcePathList());
>>
>>         DeclarationMatcher funcMatcher = functionDecl(
>> ).bind("functionMatcher");
>>
>>         *FunctionHelper funcHelper;*
>> funcHelper.setNodeBindName("functionMatcher");
>> funcHelper.MatchFinder.addMatcher(funcMatcher, &funcHelper);
>>
>> Tool.run(newFrontendActionFactory(&(funcHelper.MatchFinder)).get());
>>
>>
>> llvm::SmallVector<const clang::FunctionDecl*, 5U> allFuncDecl =
>> funcHelper.getAllFunctionDecl();
>> const FunctionDecl* fnDecl = allFuncDecl[0];
>> * cout << fnDecl->getName().str();  /* Exception Generated while calling
>> method.  If same method called from run method then it works. */*
>>
>>        return 0;
>> }
>>
>>
>> *FunctionalHelper.h*
>>
>>
>>                 typedef struct _FunctionInfo
>> {
>> std::string funcName;
>> std::string sourceFileName;
>> unsigned int paramCount;
>> }FunctionInfo;
>>
>>
>> *class FunctionHelper : public
>> clang::ast_matchers::MatchFinder::MatchCallback* {
>>
>> std::vector<FunctionInfo> m_vec_FunctionInfo;
>> std::string m_str_NodeBindName;
>> llvm::SmallVector<const clang::FunctionDecl*,5> m_vec_FunctionDecl;
>> private:
>> void run(const clang::ast_matchers::MatchFinder::MatchResult &Result)
>> override
>> {
>> const clang::FunctionDecl* tempFuncDecl = Result.Nodes.getNodeAs<clang::
>> FunctionDecl>(m_str_NodeBindName.c_str());
>>
>> *                                 // tempFuncDecl ->getName().str();
>>  //from here, it's works.*
>> if (tempFuncDecl)
>> {
>> FunctionInfo tempFuncInfo;
>> fillFunctionInfo(tempFuncDecl, tempFuncInfo);
>>
>> m_vec_FunctionInfo.push_back(tempFuncInfo);
>> m_vec_FunctionDecl.push_back(tempFuncDecl);
>> }
>> }
>>
>> public:
>> clang::ast_matchers::MatchFinder MatchFinder;
>> void setNodeBindName(std::string nodeBindName) { m_str_NodeBindName =
>> nodeBindName; };
>>
>> std::vector<FunctionInfo> getFuncInfoForAllMatchedNodes()
>> {
>> return m_vec_FunctionInfo;
>> }
>> llvm::SmallVector<const clang::FunctionDecl*,5> getAllFunctionDecl()
>> {
>> return m_vec_FunctionDecl;
>> }
>>
>> static std::string getFunctionName(const clang::FunctionDecl* funcDecl)
>> {
>> if (!funcDecl) { return ""; }
>> return funcDecl->getNameAsString();
>> }
>>
>> static std::string getSourceFileName(const clang::FunctionDecl* funcDecl)
>> {
>> if (!funcDecl) { return ""; }
>> return funcDecl->getASTContext().getSourceManager().getFilename(
>> funcDecl->getLocation()).str();
>> }
>>
>> static unsigned int getParamsCount(const clang::FunctionDecl* funcDecl)
>> {
>> if (!funcDecl) { return 0; }
>> return funcDecl->getNumParams();
>> }
>>
>> static void fillFunctionInfo(const clang::FunctionDecl* funcDecl,
>> FunctionInfo &funcInfo)
>> {
>> if (!funcDecl) { return; }
>> funcInfo.funcName = FunctionHelper::getFunctionName(funcDecl);
>> funcInfo.sourceFileName = FunctionHelper::getSourceFileName(funcDecl);
>> funcInfo.paramCount = FunctionHelper::getParamsCount(funcDecl);
>> }
>> };
>>
>>
>> Config:- 32bit, Debug
>> OS:- Windows
>> Compiled through VS2015.
>> Clang Version:- latest available. [ I guess 4.0]
>>
>> So, Need help in resolving issue.
>> Thanks In Advance.!!
>>
>> Regards,
>> Apoorva
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> cfe-dev mailing listcfe-dev at lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>> --
>> Best regards,
>> Aleksei Sidorin
>> Software Engineer,
>> IMSWL-IMCG, SRR, Samsung Electronics
>>
>> --
> Best regards,
> Aleksei Sidorin
> Software Engineer,
> IMSWL-IMCG, SRR, Samsung Electronics
>
>
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