Only emit Initializer and Finalizer from SPIR-V 1.1

The Initializer and Finalizer Execution Modes were missing before
SPIR-V 1.1.

Author: svenvh

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -3028,11 +3028,20 @@ bool LLVMToSPIRV::transExecutionMode() {
 
       switch (EMode) {
       case spv::ExecutionModeContractionOff:
-      case spv::ExecutionModeInitializer:
-      case spv::ExecutionModeFinalizer:
         BF->addExecutionMode(BM->add(
             new SPIRVExecutionMode(BF, static_cast<ExecutionMode>(EMode))));
         break;
+      case spv::ExecutionModeInitializer:
+      case spv::ExecutionModeFinalizer:
+        if (BM->isAllowedToUseVersion(VersionNumber::SPIRV_1_1)) {
+          BF->addExecutionMode(BM->add(
+              new SPIRVExecutionMode(BF, static_cast<ExecutionMode>(EMode))));
+        } else {
+          getErrorLog().checkError(false, SPIRVEC_Requires1_1,
+                                   "Initializer/Finalizer Execution Mode");
+          return false;
+        }
+        break;
       case spv::ExecutionModeLocalSize:
       case spv::ExecutionModeLocalSizeHint: {
         unsigned X, Y, Z;

llvm-spirv/lib/SPIRV/libSPIRV/SPIRVErrorEnum.h

@@ -16,3 +16,4 @@ _SPIRV_OP(FunctionPointers, "Can't translate function pointer:\n")
 _SPIRV_OP(InvalidInstruction, "Can't translate llvm instruction:\n")
 _SPIRV_OP(InvalidWordCount,
           "Can't encode instruction with word count greater than 65535:\n")
+_SPIRV_OP(Requires1_1, "Feature requires SPIR-V 1.1 or greater:")

llvm-spirv/test/CXX/global-ctor.cl

@@ -3,6 +3,7 @@
 // RUN: spirv-val %t.spv
 // RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefix=CHECK-SPIRV
 // RUN: llvm-spirv -r %t.spv -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK-LLVM
+// RUN: not llvm-spirv %t.bc --spirv-max-version=1.0 2>&1 | FileCheck %s --check-prefix=CHECK-SPV10
 
 class Something {
   public:
@@ -23,3 +24,5 @@ void kernel work(global int *out) {
 
 // CHECK-LLVM: llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @[[CTORNAME:_GLOBAL__sub_I[^ ]+]], i8* null }
 // CHECK-LLVM: define spir_kernel void @[[CTORNAME]]
+
+// CHECK-SPV10: Feature requires SPIR-V 1.1 or greater: Initializer/Finalizer Execution Mode