Fix debug info of work-item builtin translation (#745)

debug info of work-item builtins are lost in both llvm IR -> spirv and
spirv -> llvm IR translations. See #744

Author: wenju-he

llvm-spirv/lib/SPIRV/OCL20ToSPIRV.cpp

@@ -1257,11 +1257,16 @@ void OCL20ToSPIRV::transWorkItemBuiltinsToVariables() {
     for (auto UI = I.user_begin(), UE = I.user_end(); UI != UE; ++UI) {
       auto CI = dyn_cast<CallInst>(*UI);
       assert(CI && "invalid instruction");
-      Value *NewValue = new LoadInst(GVType, BV, "", CI);
+      const DebugLoc &DLoc = CI->getDebugLoc();
+      Instruction *NewValue = new LoadInst(GVType, BV, "", CI);
+      if (DLoc)
+        NewValue->setDebugLoc(DLoc);
       LLVM_DEBUG(dbgs() << "Transform: " << *CI << " => " << *NewValue << '\n');
       if (IsVec) {
         NewValue =
             ExtractElementInst::Create(NewValue, CI->getArgOperand(0), "", CI);
+        if (DLoc)
+          NewValue->setDebugLoc(DLoc);
         LLVM_DEBUG(dbgs() << *NewValue << '\n');
       }
       NewValue->takeName(CI);

llvm-spirv/lib/SPIRV/SPIRVReader.cpp

@@ -340,11 +340,16 @@ bool SPIRVToLLVM::transOCLBuiltinFromVariable(GlobalVariable *GV,
           LD->getPointerOperandType()->getPointerElementType());
       Value *EmptyVec = UndefValue::get(VecTy);
       Vectors.push_back(EmptyVec);
+      const DebugLoc &DLoc = LD->getDebugLoc();
       for (unsigned I = 0; I < VecTy->getNumElements(); ++I) {
         auto *Idx = ConstantInt::get(Type::getInt32Ty(*Context), I);
         auto *Call = CallInst::Create(Func, {Idx}, "", LD);
+        if (DLoc)
+          Call->setDebugLoc(DLoc);
         setAttrByCalledFunc(Call);
         auto *Insert = InsertElementInst::Create(Vectors.back(), Call, Idx);
+        if (DLoc)
+          Insert->setDebugLoc(DLoc);
         Insert->insertAfter(Call);
         Vectors.push_back(Insert);
       }

llvm-spirv/test/DebugInfo/builtin-get-global-id.ll

@@ -0,0 +1,66 @@
+; Check debug info of builtin get_global_id is preserved from LLVM IR to spirv
+; and spirv to LLVM IR translation.
+
+; Original .cl source:
+; kernel void test() {
+;   size_t gid = get_global_id(0);
+; }
+
+; Command line:
+; ./clang -cc1 1.cl -triple spir64 -cl-std=cl2.0 -emit-llvm -finclude-default-header -debug-info-kind=line-tables-only -O0
+
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -spirv-text -o - | FileCheck %s --check-prefix CHECK-SPIRV
+; RUN: llvm-spirv %t.bc -o %t.spv
+; RUN: llvm-spirv -r %t.spv -o - | llvm-dis -o - | FileCheck %s
+
+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"
+
+; CHECK-SPIRV: ExtInst {{.*}} DebugScope
+; CHECK-SPIRV-NEXT: Line {{[0-9]+}} 2 16
+; CHECK-SPIRV-NEXT: Load {{[0-9]+}} [[LoadRes:[0-9]+]]
+; CHECK-SPIRV-NEXT: CompositeExtract {{[0-9]+}} {{[0-9]+}} [[LoadRes]] 0
+
+; Function Attrs: convergent noinline norecurse nounwind optnone
+define spir_kernel void @test() #0 !dbg !7 !kernel_arg_addr_space !2 !kernel_arg_access_qual !2 !kernel_arg_type !2 !kernel_arg_base_type !2 !kernel_arg_type_qual !2 {
+entry:
+  %gid = alloca i64, align 8
+  %call = call spir_func i64 @_Z13get_global_idj(i32 0) #2, !dbg !10
+; CHECK: [[I0:%[0-9]]] = call spir_func i64 @_Z13get_global_idj(i32 0) #1, !dbg [[DBG:![0-9]+]]
+; CHECK-NEXT: [[I1:%[0-9]]] = insertelement <3 x i64> undef, i64 [[I0]], i32 0, !dbg [[DBG]]
+; CHECK-NEXT: [[I2:%[0-9]]] = call spir_func i64 @_Z13get_global_idj(i32 1) #1, !dbg [[DBG]]
+; CHECK-NEXT: [[I3:%[0-9]]] = insertelement <3 x i64> [[I1]], i64 [[I2]], i32 1, !dbg [[DBG]]
+; CHECK-NEXT: [[I4:%[0-9]]] = call spir_func i64 @_Z13get_global_idj(i32 2) #1, !dbg [[DBG]]
+; CHECK-NEXT: [[I5:%[0-9]]] = insertelement <3 x i64> [[I3]], i64 [[I4]], i32 2, !dbg [[DBG]]
+; CHECK-NEXT: %call = extractelement <3 x i64> [[I5]], i32 0, !dbg [[DBG]]
+  store i64 %call, i64* %gid, align 8, !dbg !11
+  ret void, !dbg !12
+}
+
+; Function Attrs: convergent nounwind readnone
+declare spir_func i64 @_Z13get_global_idj(i32) #1
+
+attributes #0 = { convergent noinline norecurse nounwind optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "uniform-work-group-size"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { convergent nounwind readnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { convergent nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!opencl.ocl.version = !{!5}
+!opencl.spir.version = !{!5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 12.0.0 (https://github.com/llvm/llvm-project.git b5bc56da8aa23dc57db9d286b0591dbcf9b1bdd3)", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "<stdin>", directory: "")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 2, i32 0}
+!6 = !{!"clang version 12.0.0 (https://github.com/llvm/llvm-project.git b5bc56da8aa23dc57db9d286b0591dbcf9b1bdd3)"}
+!7 = distinct !DISubprogram(name: "test", scope: !8, file: !8, line: 1, type: !9, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DIFile(filename: "1.cl", directory: "")
+!9 = !DISubroutineType(types: !2)
+!10 = !DILocation(line: 2, column: 16, scope: !7)
+!11 = !DILocation(line: 2, column: 10, scope: !7)
+!12 = !DILocation(line: 3, column: 1, scope: !7)