i965/fs: Add a very basic validation pass

Currently the validation pass only validates that regs_read and
regs_written are consistent with the sizes of VGRF's.  We can add more as
we find it to be useful.

Reviewed-by: Matt Turner <mattst88@gmail.com>

src/mesa/drivers/dri/i965/Makefile.sources

@@ -62,6 +62,7 @@ i965_FILES = \
 	brw_fs_sel_peephole.cpp \
 	brw_fs_surface_builder.cpp \
 	brw_fs_surface_builder.h \
+	brw_fs_validate.cpp \
 	brw_fs_vector_splitting.cpp \
 	brw_fs_visitor.cpp \
 	brw_gs.c \

src/mesa/drivers/dri/i965/brw_fs.cpp

@@ -4781,6 +4781,9 @@ fs_visitor::calculate_register_pressure()
 void
 fs_visitor::optimize()
 {
+   /* Start by validating the shader we currently have. */
+   validate();
+
    /* bld is the common builder object pointing at the end of the program we
     * used to translate it into i965 IR.  For the optimization and lowering
     * passes coming next, any code added after the end of the program without
@@ -4797,7 +4800,10 @@ fs_visitor::optimize()
    assign_constant_locations();
    demote_pull_constants();
 
+   validate();
+
    split_virtual_grfs();
+   validate();
 
 #define OPT(pass, args...) ({                                           \
       pass_num++;                                                       \
@@ -4811,6 +4817,8 @@ fs_visitor::optimize()
          backend_shader::dump_instructions(filename);                   \
       }                                                                 \
                                                                         \
+      validate();                                                       \
+                                                                        \
       progress = progress || this_progress;                             \
       this_progress;                                                    \
    })
@@ -4872,6 +4880,8 @@ fs_visitor::optimize()
    OPT(lower_integer_multiplication);
 
    lower_uniform_pull_constant_loads();
+
+   validate();
 }
 
 /**

src/mesa/drivers/dri/i965/brw_fs.h

@@ -151,6 +151,7 @@ public:
    void invalidate_live_intervals();
    void calculate_live_intervals();
    void calculate_register_pressure();
+   void validate();
    bool opt_algebraic();
    bool opt_redundant_discard_jumps();
    bool opt_cse();

src/mesa/drivers/dri/i965/brw_fs_validate.cpp

@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/** @file brw_fs_validate.cpp
+ *
+ * Implements a pass that validates various invariants of the IR.  The current
+ * pass only validates that GRF's uses are sane.  More can be added later.
+ */
+
+#include "brw_fs.h"
+#include "brw_cfg.h"
+
+#define fsv_assert(cond) \
+   if (!(cond)) { \
+      fprintf(stderr, "ASSERT: FS validation failed!\n"); \
+      dump_instruction(inst, stderr); \
+      fprintf(stderr, "%s:%d: %s\n", __FILE__, __LINE__, #cond); \
+      abort(); \
+   }
+
+void
+fs_visitor::validate()
+{
+   foreach_block_and_inst (block, fs_inst, inst, cfg) {
+      if (inst->dst.file == GRF) {
+         fsv_assert(inst->dst.reg_offset + inst->regs_written <=
+                    alloc.sizes[inst->dst.reg]);
+      }
+
+      for (unsigned i = 0; i < inst->sources; i++) {
+         if (inst->src[i].file == GRF) {
+            fsv_assert(inst->src[i].reg_offset + inst->regs_read(i) <=
+                       (int)alloc.sizes[inst->src[i].reg]);
+         }
+      }
+   }
+}