spirv: fixup infinite recursion with shader replacement

While trying to use that feature on RADV I ran into an infinite
recursion.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 97b4a6d0e3 ("compiler: SPIR-V shader replacement")
Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41751>

src/compiler/spirv/nir_spirv.h

@@ -145,6 +145,9 @@ struct spirv_to_nir_options {
 
    /* If GroupNonUniform capability is used, set this api subgroup size. */
    uint8_t group_non_uniform_subgroup_size;
+
+   /* Don't look at MESA_SPIRV_READ_PATH for replacements */
+   bool ignore_replacement;
 };
 
 enum spirv_verify_result {

src/compiler/spirv/spirv_to_nir.c

@@ -7622,7 +7622,10 @@ spirv_to_nir(const uint32_t *words, size_t word_count,
    }
 
    const char *read_path = os_get_option_secure("MESA_SPIRV_READ_PATH");
-   if (read_path) {
+   if (!options->ignore_replacement && read_path) {
+      struct spirv_to_nir_options replace_options = *options;
+      replace_options.ignore_replacement = true;
+
       char blake3_str[BLAKE3_HEX_LEN];
       _mesa_blake3_format(blake3_str, b->shader->info.source_blake3);
 
@@ -7675,7 +7678,7 @@ spirv_to_nir(const uint32_t *words, size_t word_count,
       ralloc_free(b->shader);
       ralloc_free(b);
       nir_shader* result = spirv_to_nir(replacement_words, replacement_size / sizeof(uint32_t),
-                                        spec, stage, entry_point_name, options,
+                                        spec, stage, entry_point_name, &replace_options,
                                         nir_options);
 
       free((void *)replacement_words);