Fix Cycles error with runtime compilation when there is no path to OptiX SDK

If no OPTIX_ROOT is set, nvcc fails to compile because there is a stray "-I"
in the arguments. Detect if the include path is empty and act accordingly.

Differential Revision: https://developer.blender.org/D16308

5 files changed, 43 insertions, 29 deletions

diff --git a/intern/cycles/device/cuda/device_impl.cpp b/intern/cycles/device/cuda/device_impl.cpp
index 01c021551f3..b56765208ee 100644
--- a/intern/cycles/device/cuda/device_impl.cpp
+++ b/intern/cycles/device/cuda/device_impl.cpp
@@ -232,7 +232,7 @@ string CUDADevice::compile_kernel_get_common_cflags(const uint kernel_features)
   return cflags;
 }
 
-string CUDADevice::compile_kernel(const uint kernel_features,
+string CUDADevice::compile_kernel(const string& common_cflags,
                                   const char *name,
                                   const char *base,
                                   bool force_ptx)
@@ -281,7 +281,6 @@ string CUDADevice::compile_kernel(const uint kernel_features,
   /* We include cflags into md5 so changing cuda toolkit or changing other
    * compiler command line arguments makes sure cubin gets re-built.
    */
-  string common_cflags = compile_kernel_get_common_cflags(kernel_features);
   const string kernel_md5 = util_md5_string(source_md5 + common_cflags);
 
   const char *const kernel_ext = force_ptx ? "ptx" : "cubin";
@@ -417,7 +416,8 @@ bool CUDADevice::load_kernels(const uint kernel_features)
 
   /* get kernel */
   const char *kernel_name = "kernel";
-  string cubin = compile_kernel(kernel_features, kernel_name);
+  string cflags = compile_kernel_get_common_cflags(kernel_features);
+  string cubin = compile_kernel(cflags, kernel_name);
   if (cubin.empty())
     return false;
 
diff --git a/intern/cycles/device/cuda/device_impl.h b/intern/cycles/device/cuda/device_impl.h
index a754c33f79d..bd6d806561b 100644
--- a/intern/cycles/device/cuda/device_impl.h
+++ b/intern/cycles/device/cuda/device_impl.h
@@ -77,9 +77,9 @@ class CUDADevice : public Device {
 
   bool use_adaptive_compilation();
 
-  virtual string compile_kernel_get_common_cflags(const uint kernel_features);
+  string compile_kernel_get_common_cflags(const uint kernel_features);
 
-  string compile_kernel(const uint kernel_features,
+  string compile_kernel(const string& cflags,
                         const char *name,
                         const char *base = "cuda",
                         bool force_ptx = false);
diff --git a/intern/cycles/device/hip/device_impl.h b/intern/cycles/device/hip/device_impl.h
index 9afef3789af..efdc15dca79 100644
--- a/intern/cycles/device/hip/device_impl.h
+++ b/intern/cycles/device/hip/device_impl.h
@@ -74,7 +74,7 @@ class HIPDevice : public Device {
 
   bool use_adaptive_compilation();
 
-  virtual string compile_kernel_get_common_cflags(const uint kernel_features);
+  string compile_kernel_get_common_cflags(const uint kernel_features);
 
   string compile_kernel(const uint kernel_features, const char *name, const char *base = "hip");
 
diff --git a/intern/cycles/device/optix/device_impl.cpp b/intern/cycles/device/optix/device_impl.cpp
index 6c64e7106d5..fabf4d7b69d 100644
--- a/intern/cycles/device/optix/device_impl.cpp
+++ b/intern/cycles/device/optix/device_impl.cpp
@@ -381,13 +381,44 @@ bool OptiXDevice::load_kernels(const uint kernel_features)
     return false;
   }
 
+  /* Skip creating OptiX module if only doing denoising. */
+  const bool need_optix_kernels = (kernel_features &
+                                   (KERNEL_FEATURE_PATH_TRACING | KERNEL_FEATURE_BAKING));
+
+  /* Detect existence of OptiX kernel and SDK here early. So we can error out
+   * before compiling the CUDA kernels, to avoid failing right after when
+   * compiling the OptiX kernel. */
+  string ptx_filename;
+  if (need_optix_kernels) {
+    ptx_filename = path_get(
+        (kernel_features & (KERNEL_FEATURE_NODE_RAYTRACE | KERNEL_FEATURE_MNEE)) ?
+            "lib/kernel_optix_shader_raytrace.ptx" :
+            "lib/kernel_optix.ptx");
+    if (use_adaptive_compilation() || path_file_size(ptx_filename) == -1) {
+      std::string optix_include_dir = get_optix_include_dir();
+      if (optix_include_dir.empty()) {
+        set_error(
+            "Unable to compile OptiX kernels at runtime. Set OPTIX_ROOT_DIR environment variable "
+            "to a directory containing the OptiX SDK.");
+        return false;
+      }
+      else if (!path_is_directory(optix_include_dir)) {
+        set_error(string_printf(
+            "OptiX headers not found at %s, unable to compile OptiX kernels at runtime. Install "
+            "OptiX SDK in the specified location, or set OPTIX_ROOT_DIR environment variable to a "
+            "directory containing the OptiX SDK.",
+            optix_include_dir.c_str()));
+        return false;
+      }
+    }
+  }
+
   /* Load CUDA modules because we need some of the utility kernels. */
   if (!CUDADevice::load_kernels(kernel_features)) {
     return false;
   }
 
-  /* Skip creating OptiX module if only doing denoising. */
-  if (!(kernel_features & (KERNEL_FEATURE_PATH_TRACING | KERNEL_FEATURE_BAKING))) {
+  if (!need_optix_kernels) {
     return true;
   }
 
@@ -469,28 +500,11 @@ bool OptiXDevice::load_kernels(const uint kernel_features)
   }
 
   { /* Load and compile PTX module with OptiX kernels. */
-    string ptx_data, ptx_filename = path_get(
-                         (kernel_features & (KERNEL_FEATURE_NODE_RAYTRACE | KERNEL_FEATURE_MNEE)) ?
-                             "lib/kernel_optix_shader_raytrace.ptx" :
-                             "lib/kernel_optix.ptx");
+    string ptx_data;
     if (use_adaptive_compilation() || path_file_size(ptx_filename) == -1) {
-      std::string optix_include_dir = get_optix_include_dir();
-      if (optix_include_dir.empty()) {
-        set_error(
-            "Unable to compile OptiX kernels at runtime. Set OPTIX_ROOT_DIR environment variable "
-            "to a directory containing the OptiX SDK.");
-        return false;
-      }
-      else if (!path_is_directory(optix_include_dir)) {
-        set_error(string_printf(
-            "OptiX headers not found at %s, unable to compile OptiX kernels at runtime. Install "
-            "OptiX SDK in the specified location, or set OPTIX_ROOT_DIR environment variable to a "
-            "directory containing the OptiX SDK.",
-            optix_include_dir.c_str()));
-        return false;
-      }
+      string cflags = compile_kernel_get_common_cflags(kernel_features);
       ptx_filename = compile_kernel(
-          kernel_features,
+          cflags,
           (kernel_features & (KERNEL_FEATURE_NODE_RAYTRACE | KERNEL_FEATURE_MNEE)) ?
               "kernel_shader_raytrace" :
               "kernel",
diff --git a/intern/cycles/device/optix/device_impl.h b/intern/cycles/device/optix/device_impl.h
index 817afdc8384..76c8af9bc3f 100644
--- a/intern/cycles/device/optix/device_impl.h
+++ b/intern/cycles/device/optix/device_impl.h
@@ -103,7 +103,7 @@ class OptiXDevice : public CUDADevice {
  private:
   BVHLayoutMask get_bvh_layout_mask() const override;
 
-  string compile_kernel_get_common_cflags(const uint kernel_features) override;
+  string compile_kernel_get_common_cflags(const uint kernel_features);
 
   bool load_kernels(const uint kernel_features) override;