[Bf-blender-cvs] [e9227c7] master: Fix T37706: avoid cycles crash when using a stack that exceeds SVM stack limits.

[Brecht Van Lommel]

Commit: e9227c76d480c5e7973b6bce03cce3ad414b0348
Author: Brecht Van Lommel
Date:   Thu Jan 16 22:36:30 2014 +0100
https://developer.blender.org/rBe9227c76d480c5e7973b6bce03cce3ad414b0348

Fix T37706: avoid cycles crash when using a stack that exceeds SVM stack limits.

This should be pretty rare, the shader in question had many parallel node links
because of copying the nodes many times, which is inefficient to run anyway.

===================================================================

M	intern/cycles/render/svm.cpp
M	intern/cycles/render/svm.h

===================================================================

diff --git a/intern/cycles/render/svm.cpp b/intern/cycles/render/svm.cpp
index e5140ea..538b1aa 100644
--- a/intern/cycles/render/svm.cpp
+++ b/intern/cycles/render/svm.cpp
@@ -115,6 +115,7 @@ SVMCompiler::SVMCompiler(ShaderManager *shader_manager_, ImageManager *image_man
 	background = false;
 	mix_weight_offset = SVM_STACK_INVALID;
 	use_multi_closure = use_multi_closure_;
+	compile_failed = false;
 }
 
 int SVMCompiler::stack_size(ShaderSocketType type)
@@ -164,10 +165,12 @@ int SVMCompiler::stack_find_offset(ShaderSocketType type)
 		}
 	}
 
-	fprintf(stderr, "Out of SVM stack space.\n");
-	assert(0);
+	if(!compile_failed) {
+		compile_failed = true;
+		fprintf(stderr, "Cycles: out of SVM stack space, shader \"%s\" too big.\n", current_shader->name.c_str());
+	}
 
-	return offset;
+	return 0;
 }
 
 void SVMCompiler::stack_clear_offset(ShaderSocketType type, int offset)
@@ -654,6 +657,12 @@ void SVMCompiler::compile_type(Shader *shader, ShaderGraph *graph, ShaderType ty
 		node->compile(*this);
 	}
 
+	/* if compile failed, generate empty shader */
+	if(compile_failed) {
+		svm_nodes.clear();
+		compile_failed = false;
+	}
+
 	add_node(NODE_END, 0, 0, 0);
 }
 
diff --git a/intern/cycles/render/svm.h b/intern/cycles/render/svm.h
index 9693e54..3d84a67 100644
--- a/intern/cycles/render/svm.h
+++ b/intern/cycles/render/svm.h
@@ -141,6 +141,7 @@ protected:
 	int max_stack_use;
 	uint mix_weight_offset;
 	bool use_multi_closure;
+	bool compile_failed;
 };
 
 CCL_NAMESPACE_END