Created attachment 114347 [details]
Reproducer

glLinkProgram crashes if there are multiple shaders with used arrays of constants attached to the program, and the arrays have different numbers of elements. For example:

Vertex shader:
#version 330
in vec2 in_position;
void main()
{
	const float zs[4] = float[4](0, 0, 0, 0);
	gl_Position = vec4(in_position, zs[int(in_position.x) % 4], 1.0);
}


Fragment shader:
#version 330
void main()
{
	const vec4 colours[2] = vec4[2](vec4(1, 0, 0, 0), vec4(0, 1, 0, 0));
	gl_FragColor = colours[int(gl_FragCoord.x) % 2];
}

The attached program uses these shaders and reproduces the bug.

Backtrace from Mesa 10.5.1:
> #0 linker::copy_constant_to_storage(gl_constant_value*, ir_constant const*, glsl_base_type, unsigned int, unsigned int) glsl/link_uniform_initializers.cpp:66
> #1 linker::set_uniform_initializer(void*, gl_shader_program*, char const*, glsl_type const*, ir_constant*, unsigned int) glsl/link_uniform_initializers.cpp:210
> #2 link_set_uniform_initializers(gl_shader_program*, unsigned int) glsl/link_uniform_initializers.cpp:309
> #3 link_assign_uniform_locations(gl_shader_program*, unsigned int) glsl/link_uniforms.cpp:1034
> #4 link_shaders(gl_context*, gl_shader_program*) glsl/linker.cpp:2869
> #5 _mesa_glsl_link_shader mesa/program/ir_to_mesa.cpp:3031
> #6 link_program mesa/main/shaderapi.c:932

The second argument to linker::copy_constant_to_storage, val, appears bogus, as it points to something near 0x0.

The arrays of constants do not have to be declared const in the shader, as long as all the element's values are known at compile time.

I found this using an AMD PITCAIRN gpu on Fedora 21, x86_64 architecture.