LWJGL shader normal's alias

Question

I'm writing my app with LWJGL and on some graphic cards (AMD Radeon series) I can not change the normal's name in vertex shader because something goes wrong and only one big triangle appears on the screen. Here is my code:

#version 150

//our attributes
in vec3 a_position;
in vec2 a_textureCoords;
in vec3 a_normal; //Here is an error

//send the color out to the fragment shader
out vec2 vTextureCoords;

void main(void)
{
    a_normal;
    gl_Position = vec4(a_position, 1.0);
    vTextureCoords = a_textureCoords;
}

if I change shader to this:

#version 150

//our attributes
in vec3 a_position;
in vec2 a_textureCoords;
in vec3 normal;

//send the color out to the fragment shader
out vec2 vTextureCoords;

void main(void)
{
    normal;
    gl_Position = vec4(a_position, 1.0);
    vTextureCoords = a_textureCoords;
}

Everything works fine and mesh appear as it should be. Is it normal? And my bind attribute function:

//Before
GL20.glBindAttribLocation(s_programID, 2, "a_normal");

//After
GL20.glBindAttribLocation(s_programID, 2, "normal");

edit

Attributes locations in shader:

//Before
a_normal 0
a_position 1
a_textureCoords 2

//After
a_position 0
a_textureCoords 1
normal 2

Answer 1

I'd suggest you to write something like this:

#version 150

#define POSITION  0
#define TEX_COORD 1 
#define NORMAL    2 

//our attributes
layout (location = POSITION) in vec3 a_position;
layout (location = TEX_COORD) in vec2 a_textureCoords;
layout (location = NORMAL) in vec3 a_normal;

//send the color out to the fragment shader
out vec2 vTextureCoords;

void main(void)
{
    a_normal;
    gl_Position = vec4(a_position, 1.0);
    vTextureCoords = a_textureCoords;
}

And then on java you have something like:

interface Semantic {

   interface Attr {

      int POSITION = 0;
      int TEX_COORD = 1;
      int NORMAL = 2;
   }
}

that you will use in your glVertexAttribPointer and glEnableVertexAttribute functions

Otherwise, remember to glBindAttribLocation before or glGetAttribLocation after linking the program

Ps: remember to do something useful with that a_normal otherwise the glsl compiler will optimize it out by removing it completely