intel/compiler: Pass single backend_shader argument to the vec4_live_variables constructor

The IR analysis framework requires the analysis result to be
constructible with a single argument.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>

src/intel/compiler/brw_vec4_live_variables.cpp

@@ -215,9 +215,8 @@ vec4_live_variables::compute_start_end()
    }
 }
 
-vec4_live_variables::vec4_live_variables(const simple_allocator &alloc,
-                                         cfg_t *cfg)
-   : alloc(alloc), cfg(cfg)
+vec4_live_variables::vec4_live_variables(const backend_shader *s)
+   : alloc(s->alloc), cfg(s->cfg)
 {
    mem_ctx = ralloc_context(NULL);
 
@@ -282,7 +281,7 @@ vec4_visitor::calculate_live_intervals()
     * The control flow-aware analysis was done at a channel level, while at
     * this point we're distilling it down to vgrfs.
     */
-   this->live_intervals = new(mem_ctx) vec4_live_variables(alloc, cfg);
+   this->live_intervals = new(mem_ctx) vec4_live_variables(this);
 }
 
 void

src/intel/compiler/brw_vec4_live_variables.h

@@ -31,6 +31,8 @@
 #include "brw_ir_vec4.h"
 #include "util/bitset.h"
 
+struct backend_shader;
+
 namespace brw {
 
 class vec4_live_variables {
@@ -63,7 +65,7 @@ public:
 
    DECLARE_RALLOC_CXX_OPERATORS(vec4_live_variables)
 
-   vec4_live_variables(const simple_allocator &alloc, cfg_t *cfg);
+   vec4_live_variables(const backend_shader *s);
    ~vec4_live_variables();
 
    int num_vars;