Fix crash at translation of mangled functions

Author: AlexeySotkin

lib/SPIRV/OCLUtil.cpp

@@ -178,8 +178,8 @@ unsigned getExtOp(StringRef OrigName, const std::string &GivenDemangledName) {
     case ParamType::FLOAT:
       Prefix = "f";
       break;
-    default:
-      llvm_unreachable("unknown mangling!");
+    case ParamType::UNKNOWN:
+      break;
     }
     Found = OCLExtOpMap::rfind(Prefix + DemangledName, &EOC);
   }

test/mangled_function.ll

@@ -0,0 +1,48 @@
+; Make sure translator doesn't crash if the program contains
+; a mangled function which is not an OpenCL bultin.
+; Source:
+; void __attribute__((overloadable))
+; foo(image2d_t srcImage);
+;
+; void bar(image2d_t srcImage) {
+;   foo(srcImage);
+; }
+; clang -cc1 /work/tmp/tmp.cl -cl-std=CL2.0 -triple spir-unknown-unknown  -finclude-default-header -emit-llvm -o test/mangled_function.ll
+
+; RUN: llvm-as < %s | llvm-spirv -o %t.spv
+; RUN: llvm-spirv %t.spv -o - -to-text | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv %t.spv -o - -r | llvm-dis | FileCheck %s --check-prefix=CHECK-LLVM
+
+; CHECK-SPIRV: Name [[foo:[0-9]+]] "_Z3foo14ocl_image2d_ro"
+; CHECK-SPIRV: Function {{[0-9]+}} [[foo]]
+
+; ModuleID = '/work/tmp/tmp.cl'
+source_filename = "/work/tmp/tmp.cl"
+target datalayout = "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir-unknown-unknown"
+
+%opencl.image2d_ro_t = type opaque
+
+; Function Attrs: convergent nounwind
+define spir_func void @bar(%opencl.image2d_ro_t addrspace(1)* %srcImage) local_unnamed_addr #0 {
+entry:
+; CHECK-LLVM: call spir_func void @_Z3foo14ocl_image2d_ro(%opencl.image2d_ro_t addrspace(1)* %srcImage)
+  tail call spir_func void @_Z3foo14ocl_image2d_ro(%opencl.image2d_ro_t addrspace(1)* %srcImage) #2
+  ret void
+}
+
+; Function Attrs: convergent
+declare spir_func void @_Z3foo14ocl_image2d_ro(%opencl.image2d_ro_t addrspace(1)*) local_unnamed_addr #1
+
+attributes #0 = { convergent nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "denorms-are-zero"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { convergent "correctly-rounded-divide-sqrt-fp-math"="false" "denorms-are-zero"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { convergent nounwind }
+
+!llvm.module.flags = !{!0}
+!opencl.ocl.version = !{!1}
+!opencl.spir.version = !{!1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 2, i32 0}
+!2 = !{!"clang version 9.0.0 (https://llvm.org/git/clang d81772e8081d5af6925826ebf18ade9dd0323bb9) (https://llvm.org/git/llvm 5a295517ec57c58837c5fe5cf364c0f2e609865f)"}