Fix crash caused by missing shader function definition and report the error.

BUG=17956386

Change-Id: I89f243b557b70401052b1f7db237fbc410386f64
Reviewed-on: https://swiftshader-review.googlesource.com/1190
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: <nicolascapens@google.com>
Reviewed-by: <nicolascapens@google.com>
diff --git a/src/GLES2/compiler/OutputASM.h b/src/GLES2/compiler/OutputASM.h
index f47f4ba..082816f 100644
--- a/src/GLES2/compiler/OutputASM.h
+++ b/src/GLES2/compiler/OutputASM.h
@@ -121,7 +121,7 @@
 		int readSwizzle(TIntermTyped *argument, int size);

 		bool trivial(TIntermTyped *expression, int budget);   // Fast to compute and no side effects

 		int cost(TIntermNode *expression, int budget);

-		const Function &findFunction(const TString &name);

+		const Function *findFunction(const TString &name);

 

 		int temporaryRegister(TIntermTyped *temporary);

 		int varyingRegister(TIntermTyped *varying);