[lldb-dev] Problems printing local variables with LLDB

[Christian Schafmeister]

Thank you, it is helpful to have it confirmed that at “-O0” I should have access to my variables.

Unfortunately, I’ve had this problem since I switched to LLDB two years ago and I only see it (always see it) when I’m debugging my full application (165 source files, about 150,000 lines of code).  So far, my several attempts at developing small test cases have been fruitless - small examples debug fine and all variables are visible.

Best,

.Chris.


On May 27, 2014, at 5:38 PM, Greg Clayton <gclayton at apple.com> wrote:

> File a compiler bug with your source file. At -O0 you should always have access to your variables. LLDB is just showing you what the compiler tells us.
> 
> Greg Clayton
> 
>> On May 27, 2014, at 2:11 PM, Christian Schafmeister <chris.schaf at verizon.net> wrote:
>> 
>> 
>> How do I ensure that I can print all local variables from within LLDB?
>> 
>> When I use LLDB, more than half the time when I try to print a local variable I get an error and “frame variable” shows the variable as being <variable not available>
>> 
>> I’m compiling all of my source with “-O0 -g”.   
>> 
>> I have not been able to create a small test case where this happens - all of my attempts at small test cases print local variables just fine.
>> 
>> Here is a typical compiler invocation for my debug build:
>> 
>> "clang++" -x c++ -O0 -g -Warray-bounds -Wgnu-array-member-paren-init -Wno-deprecated-register -mmacosx-version-min=10.7 -fvisibility=default -std=c++11 -stdlib=libc++ -DCONFIG_VAR_COOL -DDEBUG_ASSERTS -DDEBUG_MPS_AMS_POOL -DEXPAT -DINCLUDED_FROM_CLASP -DINHERITED_FROM_SRC -DREADLINE -DUSE_BOEHM -D_ADDRESS_MODEL_64 -D_DEBUG_BUILD -D_TARGET_OS_DARWIN -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I"../../src" -I"../../src/core" -I"../../src/core/bin/boehm/clang-darwin-4.2.1/debug/link-static" -I"/Library/Frameworks/EPD64.framework/Versions/7.2/include/python2.7" -I"/Users/meister/Development/cando/clasp/build/cando.app/Contents/Resources/externals/common/include" -I"/Users/meister/Development/cando/clasp/build/cando.app/Contents/Resources/externals/release/include" -c -o "../../src/core/bin/boehm/clang-darwin-4.2.1/debug/link-static/evaluator.o" "../../src/core/evaluator.cc"
>> 
>> 
>> Here’s an example of what I run into all the time with LLDB:
>> 
>> frame #12: 0x000000010119800e clasp_boehm_d`core::SpecialForm_O::evaluate(mem::smart_ptr<core::Cons_O>, mem::smart_ptr<core::Environment_O>) + 542 at /Users/meister/Development/cando/clasp/src/core/../../src/core/specialForm.cc:41
>>   38  	    T_mv SpecialForm_O::evaluate( Cons_sp args, Environment_sp environment )
>>   39  	    {_OF();
>>   40  		ASSERTP(this->_fptr!=NULL,"Functoid can not be NULL");
>> -> 41  		return (this->_fptr)(args,environment);
>>   42  	    }
>>   43  	
>>   44  	
>> (lldb) frame variable
>> frame variable
>> (core::SpecialForm_O *) this = 0x00000001067d4008
>> (core::Cons_sp) args = <variable not available>
>> 
>> (core::Environment_sp) environment = <variable not available>
>> 
>> (lldb) print args
>> print args
>> error: Couldn't materialize struct: size of variable args (8) disagrees with the ValueObject's size (0)
>> Errored out in Execute, couldn't PrepareToExecuteJITExpression
>> (lldb) 
>> 
>> 
>> 
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>