mesa: implement glSpecializeShaderARB (WIP)

2 files changed, 95 insertions, 1 deletions

diff --git a/src/compiler/spirv/nir_spirv.h b/src/compiler/spirv/nir_spirv.h
index 7f16866b49..34658fbfff 100644
--- a/src/compiler/spirv/nir_spirv.h
+++ b/src/compiler/spirv/nir_spirv.h
@@ -28,7 +28,7 @@
 #ifndef _NIR_SPIRV_H_
 #define _NIR_SPIRV_H_
 
-#include "nir/nir.h"
+#include "compiler/nir/nir.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/src/mesa/main/glspirv.c b/src/mesa/main/glspirv.c
index e75286aeb7..a789a20335 100644
--- a/src/mesa/main/glspirv.c
+++ b/src/mesa/main/glspirv.c
@@ -24,6 +24,10 @@
 #include "glspirv.h"
 
 #include "errors.h"
+#include "shaderobj.h"
+
+#include "compiler/nir/nir.h"
+#include "compiler/spirv/nir_spirv.h"
 
 #include "util/u_atomic.h"
 
@@ -96,4 +100,94 @@ _mesa_SpecializeShaderARB(GLuint shader,
                           const GLuint *pConstantIndex,
                           const GLuint *pConstantValue)
 {
+   GET_CURRENT_CONTEXT(ctx);
+   struct gl_shader *sh;
+   nir_shader *nir;
+   nir_function *entry_point;
+
+   if (!ctx->Extensions.ARB_gl_spirv) {
+      _mesa_error(ctx, GL_INVALID_OPERATION, "glSpecializeShaderARB");
+      return;
+   }
+
+   sh = _mesa_lookup_shader_err(ctx, shader, "glSpecializeShaderARB");
+   if (!sh)
+      return;
+
+   if (!sh->SpirVBinary) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glSpecializeShaderARB(not SPIR-V)");
+      return;
+   }
+
+   if (sh->CompileStatus) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "glSpecializeShaderARB(already specialized)");
+      return;
+   }
+
+   /* From the GL_ARB_gl_spirv spec:
+    *
+    *    "The OpenGL API expects the SPIR-V module to have already been
+    *     validated, and can return an error if it discovers anything invalid
+    *     in the module. An invalid SPIR-V module is allowed to result in
+    *     undefined behavior."
+    *
+    * However, the following errors still need to be detected (from the same
+    * spec):
+    *
+    *    "INVALID_VALUE is generated if <pEntryPoint> does not name a valid
+    *     entry point for <shader>.
+    *
+    *     INVALID_VALUE is generated if any element of <pConstantIndex>
+    *     refers to a specialization constant that does not exist in the
+    *     shader module contained in <shader>."
+    *
+    * We cannot flag those errors a-priori because detecting them requires
+    * parsing the module. However, flagging them during specialization is okay,
+    * since it makes no difference in terms of application-visible state.
+    */
+   {
+      struct nir_spirv_specialization *spec_entries =
+         calloc(sizeof(*spec_entries), numSpecializationConstants);
+
+      for (unsigned i = 0; i < numSpecializationConstants; ++i) {
+         spec_entries[i].id = pConstantIndex[i];
+         spec_entries[i].data32 = pConstantValue[i];
+      }
+
+      entry_point = spirv_to_nir((uint32_t *)&sh->SpirVModule->Binary[0],
+                                 sh->SpirVModule->Length / 4,
+                                 spec_entries, numSpecializationConstants,
+                                 sh->Stage, pEntryPoint,
+                                 ctx->Const.SpirVExtensions,
+                                 ctx->Const.SpirVNIROptions);
+      nir = entry_point->shader;
+      assert(nir->stage == sh->Stage);
+
+      nir->info.stage = nir->stage;
+      nir->info.name = ralloc_asprintf(nir, "SPIRV:%s:%d",
+                                       _mesa_shader_stage_to_abbrev(nir->stage),
+                                       sh->Name);
+
+      nir_validate_shader(nir);
+
+      free(spec_entries);
+   }
+
+   /* TODO: Perform some common optimizations already here, to avoid re-doing
+    * them each time the shader is linked.
+    */
+
+   /* TODO: Clone to cleanup memory (can only be done after inlining). */
+   sh->nir = nir;
+   sh->nir_entry = entry_point;
+   ralloc_steal(sh, sh->nir);
+
+   sh->CompileStatus = compile_success;
+
+   /* Disable the shader disk cache for SPIR-V shaders for now. */
+   memset(sh->sha1, 0, sizeof(sh->sha1));
+
+   _mesa_spirv_module_reference(&sh->SpirVModule, NULL);
 }