nv50: be more cautious about using reg_instance

Trying to free part of nv50_pc->reg_instances[] for an
nv50_reg representing an indirect constant resulted in
a segmentation fault.

diff --git a/src/gallium/drivers/nv50/nv50_program.c b/src/gallium/drivers/nv50/nv50_program.c
index fe8ccd034943b33c129c5a0915965ad68c0631a0..e496cf4cad84ef0774fad5d14efe7af2057dd693 100644 (file)
--- a/src/gallium/drivers/nv50/nv50_program.c
+++ b/src/gallium/drivers/nv50/nv50_program.c
@@ -156,14 +156,15 @@ struct nv50_pc {
 static INLINE struct nv50_reg *
 reg_instance(struct nv50_pc *pc, struct nv50_reg *reg)
 {
-       struct nv50_reg *dup = NULL;
+       struct nv50_reg *ri;
+
+       assert(pc->reg_instance_nr < 16);
+       ri = &pc->reg_instances[pc->reg_instance_nr++];
        if (reg) {
-               assert(pc->reg_instance_nr < 16);
-               dup = &pc->reg_instances[pc->reg_instance_nr++];
-               *dup = *reg;
+               *ri = *reg;
                reg->mod = 0;
        }
-       return dup;
+       return ri;
 }
 
 static INLINE void
@@ -1886,7 +1887,7 @@ tgsi_src(struct nv50_pc *pc, int chan, const struct tgsi_full_src_register *src,
                        /* Indicate indirection by setting r->acc < 0 and
                         * use the index field to select the address reg.
                         */
-                       r = MALLOC_STRUCT(nv50_reg);
+                       r = reg_instance(pc, NULL);
                        swz = tgsi_util_get_src_register_swizzle(
                                                 &src->Indirect, 0);
                        ctor_reg(r, P_CONST,
@@ -1940,6 +1941,8 @@ tgsi_src(struct nv50_pc *pc, int chan, const struct tgsi_full_src_register *src,
                break;
        }
 
+       if (r && r->acc >= 0 && r != temp)
+               return reg_instance(pc, r);
        return r;
 }
 
@@ -2094,8 +2097,7 @@ nv50_program_tx_insn(struct nv50_pc *pc,
 
                for (c = 0; c < 4; c++)
                        if (src_mask & (1 << c))
-                               src[i][c] = reg_instance(pc,
-                                       tgsi_src(pc, c, fs, neg_supp));
+                               src[i][c] = tgsi_src(pc, c, fs, neg_supp);
        }
 
        brdc = temp = pc->r_brdc;
@@ -2466,15 +2468,6 @@ nv50_program_tx_insn(struct nv50_pc *pc,
                }
        }
 
-       for (i = 0; i < inst->Instruction.NumSrcRegs; i++) {
-               for (c = 0; c < 4; c++) {
-                       if (!src[i][c])
-                               continue;
-                       if (src[i][c]->acc < 0 && src[i][c]->type == P_CONST)
-                               FREE(src[i][c]); /* indirect constant */
-               }
-       }
-
        kill_temp_temp(pc);
        pc->reg_instance_nr = 0;