nir: add NIR_PASS_ASSERT_NO_PROGRESS

This aborts if a pass would make any progress. It can be used to assert that:
- our minimalist pass invocation loops in drivers are sufficient and don't
  leave any unoptimized code in the shader
- our lowering is sufficient and other passes don't add instructions that
  would cause lowering having to be repeated

Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@intel.com>
Acked-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38406>

src/compiler/nir/nir.h

@@ -4916,6 +4916,30 @@ do {                                                                 \
 
 #define NIR_SKIP(name) should_skip_nir(#name)
 
+#ifndef NDEBUG
+
+void _nir_assert_no_progress(bool progress, const char *when);
+
+/* Abort if the pass has made any progress. This can be used to assert that:
+ * - our minimalist pass invocation loops in drivers are sufficient and don't
+ *   leave any unoptimized code in the shader
+ * - our lowering is sufficient and other passes don't add instructions that
+ *   would cause lowering having to be repeated
+ */
+#define NIR_PASS_ASSERT_NO_PROGRESS(nir, pass, ...) \
+   do { \
+      if (!NIR_DEBUG(NOVALIDATE)) { \
+         static const char *when = #pass " in " __FILE__ ":" NIR_STRINGIZE(__LINE__); \
+         bool _progress = false; \
+         NIR_PASS(_progress, nir, pass, ##__VA_ARGS__); \
+         _nir_assert_no_progress(_progress, when); \
+      } \
+   } while (0)
+
+#else
+#define NIR_ASSERT_PASS_NO_PROGRESS(nir, pass, ...)
+#endif
+
 /** An instruction filtering callback with writemask
  *
  * Returns true if the instruction should be processed with the associated

src/compiler/nir/nir_validate.c

@@ -2355,4 +2355,23 @@ nir_validate_ssa_dominance(nir_shader *shader, const char *when)
    destroy_validate_state(&state);
 }
 
+void
+_nir_assert_no_progress(bool progress, const char *when)
+{
+   if (!progress)
+      return;
+
+   /* Lock around dumping so that we get clean dumps in a multi-threaded
+    * scenario.
+    */
+   simple_mtx_lock(&fail_dump_mutex);
+
+   fprintf(stderr, "NIR assertion failed: Expected no progress from %s.\n",
+           when);
+   fflush(stderr);
+
+   simple_mtx_unlock(&fail_dump_mutex);
+   abort();
+}
+
 #endif /* NDEBUG */