llvm dev - Dec 2010 - [LLVMdev] wxGTK sample app compiled by llvm crashes on arm

* *Hello,

I am using llvm-2.7 to run a native(executable) on a arm processor.

I have built my wxGtk sample app with llvm-gcc as frontend .

I am using llvm-2.7 and llvm-gcc-4.2.

I built llvm-2.7   with:

../llvm-2.7/configure --prefix=/home/install-llvm  --enable-optimized
--enable-assertions

and llvm gcc with:

../llvm-gcc-4.2-2.7.source/configure --prefix=/home//gcc-disable-shared
--enable-languages=c++,c --enable-checking --enable-llvm=/home/ llvm-objects
--disable-bootstrap --disable-multilib
Now from Samples, I am compiling minimal.cpp by llvm-gcc (binary for x86)
using the following commands:

*Step 1. llvm-gcc -O3 -emit-llvm minimal.cpp -c -o minimal.bc `wxconfig
–cxxflags`*

*Step 2. llc minimal.bc  –march=arm –o minimal.s   (*for generating arm
assembly code*)*

*Step 3 arm_v7_vfp_le-gcc minimal.s –o minimal.native `wxconfig –libs` (*arm
compiler to compile this assembly code into native executable*)*

Now when I am running this native executable on my target it is crashing in
g_object new(). However, if I build my application(wxGTK application) with a
memory allocation using new in the very start, the same exe now would run
successfully.

For your reference I am posting both the codes:

*Case 1: Crash* at a point when it tries to allocate memory in making an
object of MyFrame in the code below.
bool MyApp::OnInit()
{
        if ( !wxApp::OnInit() )
                return false;
                // create the main application window
        MyFrame *frame = new MyFrame(_T("Minimal wxWidgets App"));
        frame->Show(true);
         return true;
}

*Case 2*: The code below is same as above except the first line in the
function body and it *runs fine* .
bool MyApp::OnInit()
{
  *   char *ptr = new char[10000];*
     if ( !wxApp::OnInit() )
                return false;
                // create the main application window
        MyFrame *frame = new MyFrame(_T("Minimal wxWidgets App"));
        frame->Show(true);
         return true;
}

Can anybody give us an explanation for this??

How does using *new *in the start makes a difference??



Thanks & Regards,

Ankur Jain

Senior Software Engineer
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> I am using llvm-2.7 to run a native(executable) on a arm processor.
ARM was pretty much broken in 2.7. Consider using at least 2.8
> ../llvm-gcc-4.2-2.7.source/configure --prefix=/home//gcc-disable-shared
--enable-languages=c++,c --enable-checking --enable-llvm=/home/ llvm-objects
--disable-bootstrap --disable-multilib
You have to configure llvm-gcc as cross-arm compiler.
> Step 1. llvm-gcc -O3 -emit-llvm minimal.cpp -c -o minimal.bc `wxconfig
–cxxflags`
> Step 2. llc minimal.bc  –march=arm –o minimal.s   (for generating arm
assembly code)
This won't work. You're trying to codegen x86 IR for ARM.

--
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

Thanx for a prompt reply.

I will definitely try llvm 2.8 as per your suggestion.

However Step 1 and Step 2 are working for me in case of a simple hello world
program on arm processor . Similarly I am able to run a GTK application on
arm. However while running wxGTKwidget app it crashes while allocation of
memory. As  I mentioned earlier, If I explicitly allocate memory using new
operation then everything works fine. Please let me know why do we actually
fail without using new, that to a arbitrary pointer which is never used in
the program.

On Fri, Dec 3, 2010 at 6:31 PM, Anton Korobeynikov
<anton at korobeynikov.info>wrote:
> > I am using llvm-2.7 to run a native(executable) on a arm processor.
> ARM was pretty much broken in 2.7. Consider using at least 2.8
>
> > ../llvm-gcc-4.2-2.7.source/configure
--prefix=/home//gcc-disable-shared
> --enable-languages=c++,c --enable-checking --enable-llvm=/home/
llvm-objects
> --disable-bootstrap --disable-multilib
> You have to configure llvm-gcc as cross-arm compiler.
>
> > Step 1. llvm-gcc -O3 -emit-llvm minimal.cpp -c -o minimal.bc `wxconfig
> –cxxflags`
> > Step 2. llc minimal.bc  –march=arm –o minimal.s   (for generating arm
> assembly code)
> This won't work. You're trying to codegen x86 IR for ARM.
>
> --
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State University
>
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