[lldb-dev] lldb crash

[Enrico Granata]

Andrey,
You might be pleased to know that this bug is fixed in the latest LLDB.

What follows is an LLDB session printout, with the interesting lines bolded

da0603a-dhcp151:Debug egranata$ ./lldb andrey
Current executable set to 'andrey' (x86_64).
(lldb) b main
runbreakpoint set --name 'main'
Breakpoint created: 1: name = 'main', locations = 1
(lldb) run
Process 71825 launched: '/Volumes/work/egranata/lldb/build/Debug/andrey' (x86_64)
Process 71825 stopped
* thread #1: tid = 0x2e03, 0x0000000100000d94 andrey`main + 4 at andrey.m:18, stop reason = breakpoint 1.1
  frame #0: 0x0000000100000d94 andrey`main + 4 at andrey.m:18
   15  	
   16  	int main()
   17  	{
-> 18  	    Item *itm = [[Item alloc] init];
   19  	    
   20  	    itm.title = @"Hello world";
   21  	    
(lldb) n
Process 71825 stopped
* thread #1: tid = 0x2e03, 0x0000000100000ddb andrey`main + 75 at andrey.m:20, stop reason = step over
  frame #0: 0x0000000100000ddb andrey`main + 75 at andrey.m:20
   17  	{
   18  	    Item *itm = [[Item alloc] init];
   19  	    
-> 20  	    itm.title = @"Hello world";
   21  	    
   22  	    itm.title = @"Try again";
   23  	    
(lldb) n
Process 71825 stopped
* thread #1: tid = 0x2e03, 0x0000000100000e00 andrey`main + 112 at andrey.m:22, stop reason = step over
  frame #0: 0x0000000100000e00 andrey`main + 112 at andrey.m:22
   19  	    
   20  	    itm.title = @"Hello world";
   21  	    
-> 22  	    itm.title = @"Try again";
   23  	    
   24  	    return 0;
   25
(lldb) expr (char*)[[itm title] UTF8String]
(char *) $0 = 0x000000010010cdc0 "Hello world"

You can get the latest LLDB source from the project website and build it yourself. This should be enough to solve your crash

Thanks for your interest in LLDB :-)

On Jul 14, 2011, at 5:32 AM, Andrey Zaytsev wrote:

> I've got crash when was trying to call GetNumChildren of value which I got from EvaluateExpression method.
> 
> We have class:
> 
> @interface Item : NSObject {
> @private
>    NSString *title;
>    NSString *type;
> }
> 
> @property(retain)NSString* title;
> //... and some other stupid stuff
> @end
> 
> I'm trying to evaluate expression "[item title]"
> Value is ok. But when GetNumChildren is invoked i've got crash: 
> ClangASTContext.cpp:
> 
> static bool
> GetCompleteQualType (clang::ASTContext *ast, clang::QualType qual_type) {
> //......
> 
> case clang::Type::ObjCInterface:
>        {
>            const clang::ObjCObjectType *objc_class_type = dyn_cast<clang::ObjCObjectType>(qual_type);
>            if (objc_class_type)
>            {
>                clang::ObjCInterfaceDecl *class_interface_decl = objc_class_type->getInterface();
>                // We currently can't complete objective C types through the newly added ASTContext
>                // because it only supports TagDecl objects right now...
>                bool is_forward_decl = class_interface_decl->isForwardDecl();  // !! <----- crashed here. class_interface_decl == NULL
> 
> Sorry for screenshot instead of normal crash dump. =( I just was not able to get it.
> 
> <Screen shot 2011-07-14 at 15.55.09.png>
> 
> CFBundleVersion of LLDB is 63.
> 
> I couldn't reproduce it with Xcode (just because of "Evaluate expression" doesn't work at all with message "Invalid expression")
> 
> Please please please fix it! 
> Thank you._______________________________________________
> lldb-dev mailing list
> lldb-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev

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