nir: Try to warn when C99 extensions are used in nir headers.

Ideally we'd have nir.h being included with -Wpedantic too, but it fails
with:

src/compiler/nir/nir.h:754:20: warning: ISO C++ forbids zero-size array ‘src’ [-Wpedantic]
    nir_alu_src src[];
                    ^
In file included from src/compiler/nir/glsl_to_nir.cpp:42:0:
src/compiler/nir/nir.h:919:16: warning: ISO C++ forbids zero-size array ‘src’ [-Wpedantic]
    nir_src src[];

Reviewed-by: Connor Abbott <[email protected]>

1 files changed, 22 insertions, 1 deletions

diff --git a/src/compiler/nir/glsl_to_nir.cpp b/src/compiler/nir/glsl_to_nir.cpp
index e3fa623ba04..c8954ceeeb1 100644
--- a/src/compiler/nir/glsl_to_nir.cpp
+++ b/src/compiler/nir/glsl_to_nir.cpp
@@ -25,9 +25,30 @@
  *
  */
 
-#include "glsl_to_nir.h"
+#include "nir.h"
+
+/*
+ * Have GCC/Clang warn when NIR headers use C99 extensions that are not
+ * supported in C++, as they are not portable.  In particular MSVC does not
+ * support C99 structure field initializers.
+ */
+#if defined(__GNUC__)
+#  pragma GCC diagnostic push
+#  if defined(__clang__)
+#    pragma GCC diagnostic warning "-Wc99-extensions"
+#  else
+#    pragma GCC diagnostic warning "-Wpedantic"
+#  endif
+#endif
+
 #include "nir_control_flow.h"
 #include "nir_builder.h"
+
+#if defined(__GNUC__)
+#  pragma GCC diagnostic pop
+#endif
+
+#include "glsl_to_nir.h"
 #include "compiler/glsl/ir_visitor.h"
 #include "compiler/glsl/ir_hierarchical_visitor.h"
 #include "compiler/glsl/ir.h"