Hey all, I've noticed a bug in Mesa's treatment of the #line directive in GLSL 3.3+.

The 3.3 spec changed the line number set by #line to be the line number for the following line of source (pg 11 GLSL 3.3 spec):

    #line `line`
    #line `line` `source-string-number`

> After processing this directive (including its new-line), the implementation  
> will behave as if it is compiling at line number `line` and source string
> number `source-string-number`. Subsequent source strings will be numbered
> sequentially, until another #line directive overrides that numbering.

So for a shader with some silly error in it:

    #version 330 core
    #line 1 4
    not_valid vec4 thingy_error;
    #line 1 0
    layout(location = 0) in vec4 pos;
    void main(void){
        gl_Position = pos;
    }

We'd expect the error to specify something about the incorrect identifier/token w/e on line 1 of source string 4, however Mesa's compilation log contains the following:

> 0:2(1): error: syntax error, unexpected NEW_IDENTIFIER

From some other shader compilers it seems like the first number refers to the source string number, which should be 4 here. The compiler also seems to be using the GLSL 1.5 line directive where the following line is line number `line` + 1.

Nvidia's compiler gives the expected source string number and line number:

> 4(1) : warning C7022: unrecognized profile specifier "not_valid"
> 4(1) : error C0502: syntax error at token "not_valid"

Information about my Mesa & GL version:

> OpenGL Version: 3.3 (Core Profile) Mesa 10.1.3
> OpenGL Vendor: Intel Open Source Technology Center
> OpenGL Renderer: Mesa DRI Intel(R) Ivybridge Mobile 
> GLSL Version: 3.30

Thanks!