Report unmet version requirement as error (#2372)

When restricting the allowed SPIR-V version using
`--spirv-max-version`, some constructs may not be translatable due to
being unavailable in older SPIR-V versions.  Instead of asserting,
report an error.

It would be nice to also report the construct leading to the version
conflict, but that information isn't readily available at this point.

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@cebf8ecc9ec099b

Author: svenvh

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

@@ -20,6 +20,7 @@ _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:")
+_SPIRV_OP(RequiresVersion, "Cannot fulfill SPIR-V version restriction:\n")
 _SPIRV_OP(RequiresExtension,
           "Feature requires the following SPIR-V extension:\n")
 _SPIRV_OP(InvalidMagicNumber,

llvm-spirv/lib/SPIRV/libSPIRV/SPIRVModule.cpp

@@ -58,6 +58,18 @@
 
 namespace SPIRV {
 
+namespace {
+std::string to_string(uint32_t Version) {
+  std::string Res(formatVersionNumber(Version));
+  Res += " (" + std::to_string(Version) + ")";
+  return Res;
+}
+
+std::string to_string(VersionNumber Version) {
+  return to_string(static_cast<uint32_t>(Version));
+}
+} // Anonymous namespace
+
 SPIRVModule::SPIRVModule()
     : AutoAddCapability(true), ValidateCapability(false), IsValid(true) {}
 
@@ -173,7 +185,16 @@ class SPIRVModuleImpl : public SPIRVModule {
   void insertEntryNoId(SPIRVEntry *Entry) override { EntryNoId.insert(Entry); }
 
   void setSPIRVVersion(SPIRVWord Ver) override {
-    assert(this->isAllowedToUseVersion(static_cast<VersionNumber>(Ver)));
+    if (!this->isAllowedToUseVersion(static_cast<VersionNumber>(Ver))) {
+      std::stringstream SS;
+      SS << "SPIR-V version was restricted to at most "
+         << to_string(getMaximumAllowedSPIRVVersion())
+         << " but a construct from the input requires SPIR-V version "
+         << to_string(Ver) << " or above\n";
+      getErrorLog().checkError(false, SPIRVEC_RequiresVersion, SS.str());
+      setInvalid();
+      return;
+    }
     SPIRVVersion = Ver;
   }
 
@@ -2098,16 +2119,6 @@ void SPIRVModuleImpl::addUnknownStructField(SPIRVTypeStruct *Struct, unsigned I,
   UnknownStructFieldMap[Struct].push_back(std::make_pair(I, ID));
 }
 
-static std::string to_string(uint32_t Version) {
-  std::string Res(formatVersionNumber(Version));
-  Res += " (" + std::to_string(Version) + ")";
-  return Res;
-}
-
-static std::string to_string(VersionNumber Version) {
-  return to_string(static_cast<uint32_t>(Version));
-}
-
 std::istream &operator>>(std::istream &I, SPIRVModule &M) {
   SPIRVDecoder Decoder(I, M);
   SPIRVModuleImpl &MI = *static_cast<SPIRVModuleImpl *>(&M);

llvm-spirv/test/negative/feature_requires_minversion.ll

@@ -0,0 +1,44 @@
+; Check whether the translator reports an error for a module that uses a
+; construct only available in a SPIR-V version that's higher than what was
+; requested using --spirv-max-version.
+
+; RUN: llvm-as < %s -o %t.bc
+; RUN: not llvm-spirv --spirv-max-version=1.0 %t.bc 2>&1 | FileCheck %s
+; RUN: not llvm-spirv --spirv-max-version=1.1 %t.bc 2>&1 | FileCheck %s
+; RUN: not llvm-spirv --spirv-max-version=1.2 %t.bc 2>&1 | FileCheck %s
+; RUN: llvm-spirv --spirv-max-version=1.3 %t.bc -o %t.spv
+; RUN: spirv-val %t.spv
+
+; CHECK: RequiresVersion: Cannot fulfill SPIR-V version restriction:
+; CHECK-NEXT: SPIR-V version was restricted to at most 1.{{[012]}} ([[#]]) but a construct from the input requires SPIR-V version 1.3 (66304) or above
+
+; ModuleID = 'foo.bc'
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64"
+
+; Function Attrs: convergent
+declare dso_local spir_func <4 x i32> @_Z16sub_group_balloti(i32) local_unnamed_addr #1
+
+; Function Attrs: nounwind
+define dso_local spir_kernel void @testVersionReq() local_unnamed_addr #0 !kernel_arg_addr_space !3 !kernel_arg_access_qual !3 !kernel_arg_type !3 !kernel_arg_base_type !3 !kernel_arg_type_qual !3 {
+entry:
+  %1 = tail call spir_func <4 x i32> @_Z16sub_group_balloti(i32 0) #1
+  ret void
+}
+
+attributes #0 = { nounwind }
+attributes #1 = { convergent }
+
+!spirv.MemoryModel = !{!0}
+!opencl.enable.FP_CONTRACT = !{}
+!spirv.Source = !{!1}
+!opencl.spir.version = !{!0}
+!opencl.ocl.version = !{!0}
+!opencl.used.extensions = !{!2}
+!opencl.used.optional.core.features = !{!2}
+!spirv.Generator = !{!2}
+
+!0 = !{i32 1, i32 2}
+!1 = !{i32 3, i32 102000}
+!2 = !{}
+!3 = !{}