ATI bug with separable vertex shader

[l_belev]

Another separable shader-related bug;
A separable vertex shader (that is, a separable program object that only contains a vertex shader) does not recognize the build in variables gl_Position, gl_ClipDistance and gl_PointSize.
The compilation is successful but the link fails with the error:
ERROR: 0:4: error(#143) Undeclared identifier gl_Position

I tried declaring them explicitly. Then it compiles and links ok but gives warning about re-declaring of built-ins.
If gl_ClipDistances is declared too, the shader compiles and links ok but does not work.

here is simple win32-based code that reproduces the bug:

#include <string.h>
#include <windows.h>
#include <GL/gl.h>
#include "glext.h"
 
void separable_vertex_shader_test()
{
	static const char text[] =
		"#version 330\n"
		"#extension GL_ARB_separate_shader_objects : enable\n"
		"void main() {\n"
		"	gl_Position = vec4(0);\n"
		"}\n";
	const char *src = text;
	GLint len = sizeof(text);
	GLuint shader, prog;
	GLenum status;
 
	PFNGLCREATESHADERPROC _glCreateShader;
	PFNGLSHADERSOURCEPROC _glShaderSource;
	PFNGLCOMPILESHADERPROC _glCompileShader;
	PFNGLGETSHADERIVPROC _glGetShaderiv;
	PFNGLCREATEPROGRAMPROC _glCreateProgram;
	PFNGLPROGRAMPARAMETERIPROC _glProgramParameteri;
	PFNGLATTACHSHADERPROC _glAttachShader;
	PFNGLLINKPROGRAMPROC _glLinkProgram;
	PFNGLGETPROGRAMINFOLOGPROC _glGetProgramInfoLog;
	PFNGLGETPROGRAMIVPROC _glGetProgramiv;
 
	*(void **)&amp;_glCreateShader = (void *)wglGetProcAddress("glCreateShader");
	*(void **)&amp;_glShaderSource = (void *)wglGetProcAddress("glShaderSource");
	*(void **)&amp;_glCompileShader = (void *)wglGetProcAddress("glCompileShader");
	*(void **)&amp;_glGetShaderiv = (void *)wglGetProcAddress("glGetShaderiv");
	*(void **)&amp;_glCreateProgram = (void *)wglGetProcAddress("glCreateProgram");
	*(void **)&amp;_glProgramParameteri = (void *)wglGetProcAddress("glProgramParameteri");
	*(void **)&amp;_glAttachShader = (void *)wglGetProcAddress("glAttachShader");
	*(void **)&amp;_glLinkProgram = (void *)wglGetProcAddress("glLinkProgram");
	*(void **)&amp;_glGetProgramInfoLog = (void *)wglGetProcAddress("glGetProgramInfoLog");
	*(void **)&amp;_glGetProgramiv = (void *)wglGetProcAddress("glGetProgramiv");
 
	shader = _glCreateShader(GL_VERTEX_SHADER);
	_glShaderSource(shader, 1, &amp;src, &amp;len);
	_glCompileShader(shader);
	_glGetShaderiv(shader, GL_COMPILE_STATUS, &amp;status);
	if (status == GL_FALSE) _asm int 3
 
	prog = _glCreateProgram();
	_glProgramParameteri(prog, GL_PROGRAM_SEPARABLE, GL_TRUE);
	_glAttachShader(prog, shader);
	_glLinkProgram(prog);
	_glGetProgramiv(prog, GL_LINK_STATUS, &amp;status);
	if (status == GL_FALSE) {
		char log[65536];
		GLint log_size;
		_glGetProgramInfoLog(prog, sizeof(log), &amp;log_size, log);
		_asm int 3
	}
}
 
LRESULT CALLBACK wnd_proc(HWND wnd, UINT msg, WPARAM wp, LPARAM lp)
{
	switch (msg) {
	case WM_NCCREATE: return 1;
	case WM_PAINT: ValidateRect(wnd, NULL);
	default: return 0;
	}
}
 
int CALLBACK WinMain(HINSTANCE inst, HINSTANCE prev_inst, char *cl, int cs)
{
	WNDCLASSA wc;
	HWND wnd;
	HDC dc;
	PIXELFORMATDESCRIPTOR pfd;
	int pf;
	HGLRC rc;
 
	memset(&amp;wc, 0, sizeof(wc));
	wc.hInstance = inst;
	wc.lpfnWndProc = wnd_proc;
	wc.lpszClassName = "_test_class_name";
	RegisterClassA(&amp;wc);
	wnd = CreateWindowExA(0, wc.lpszClassName, NULL, WS_POPUP, 0, 0, 64, 32, NULL, NULL, NULL, NULL);
	dc = GetDC(wnd);
	memset(&amp;pfd, 0, sizeof(pfd));
	pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);
	pfd.nVersion = 1;
	pfd.dwFlags = PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL|PFD_DEPTH_DONTCARE;
	pf = ChoosePixelFormat(dc, &amp;pfd);
	SetPixelFormat(dc, pf, NULL);
	rc = wglCreateContext(dc);
	wglMakeCurrent(dc, rc);
 
	separable_vertex_shader_test();
 
	return 0;
}

[Alfonse Reinheart]

What driver version?