[NVPTX] Keep metadata attached to module-scope variables

[ikudrin]

Summary

This helps to preserve the debug information of global variables.

[ikudrin]

Gentle ping.

[tra]

Good catch! Thank you for fixing this.

Sorry about the delay. I've apparently failed to click "Submit". :-/

llvm/lib/Target/NVPTX/NVPTXGenericToNVVM.cpp

for (GlobalVariable &GV : llvm::make_early_inc_range(M.globals())) {
     if (GV.getType()->getAddressSpace() == llvm::ADDRESS_SPACE_GENERIC &&
         !llvm::isTexture(GV) && !llvm::isSurface(GV) && !llvm::isSampler(GV) &&
         !GV.getName().startswith("llvm.")) {
       GlobalVariable *NewGV = new GlobalVariable(
           M, GV.getValueType(), GV.isConstant(), GV.getLinkage(),
           GV.hasInitializer() ? GV.getInitializer() : nullptr, "", &GV,
           GV.getThreadLocalMode(), llvm::ADDRESS_SPACE_GLOBAL);
       NewGV->copyAttributesFrom(&GV);
+      NewGV->copyMetadata(&GV, /*Offset=*/0);
       GVMap[&GV] = NewGV;
     }
   }
 
   // Return immediately, if every global variable has a specific address space
   // specifier.
   if (GVMap.empty()) {
     return false;

llvm/test/CodeGen/NVPTX/generic-to-nvvm-ir.ll

 ; Verify functionality of NVPTXGenericToNVVM.cpp pass.
 ;
 ; RUN: opt < %s -march nvptx64 -S -generic-to-nvvm | FileCheck %s
 
 target datalayout = "e-i64:64-v16:16-v32:32-n16:32:64"
 target triple = "nvptx64-nvidia-cuda"
 
 ; Generic space variables should be converted to global space AKA addrspace(1).
-; CHECK-DAG: @static_var = {{.*}}addrspace(1)
+; The debug info reference should be preserved.
+; CHECK-DAG: @static_var = {{.*}}addrspace(1) {{.*}} !dbg !{{[0-9]+}}
 @static_var = externally_initialized global i8 0, align 1, !dbg !4
 ; CHECK-DAG: @.str = {{.*}}addrspace(1)
 @.str = private unnamed_addr constant [4 x i8] c"XXX\00", align 1
 
 ; Function Attrs: convergent
 define void @func() !dbg !8 {
 ;CHECK-LABEL: @func()
 ;CHECK-SAME: !dbg [[FUNCNODE:![0-9]+]]

 
 !llvm.dbg.cu = !{!0}
 ; CHECK: !llvm.dbg.cu = !{[[CUNODE:![0-9]+]]}
 !llvm.module.flags = !{!6, !7}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1,
       producer: "clang version 4.0.0",
       isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
-; CHECK: [[CUNODE]] = distinct !DICompileUnit({{.*}} globals: [[GLOBALSNODE:![0-9]+]]
+; CHECK-DAG: [[CUNODE]] = distinct !DICompileUnit({{.*}} globals: [[GLOBALSNODE:![0-9]+]]
 !1 = !DIFile(filename: "foo.cu", directory: "/usr/local/google/home/tra/work/llvm/build/gpu/debug")
 !2 = !{}
 !3 = !{!4}
 ; Find list of global variables and make sure it's the one used by DICompileUnit
-; CHECK: [[GLOBALSNODE]] = !{[[GVNODE:![0-9]+]]}
+; CHECK-DAG: [[GLOBALSNODE]] = !{[[GVNODE:![0-9]+]]}
 !4 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "static_var", scope: !0, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true), expr: !DIExpression())
-; Debug info must also be updated to reflect new address space.
-; CHECK: [[GVNODE]] = !DIGlobalVariableExpression(var: [[GVVAR:.*]], expr: !DIExpression())
-; CHECK: [[GVVAR]] = !DIGlobalVariable(name: "static_var"
-; CHECK-SAME: scope: [[CUNODE]]
-; CHECK-SAME: type: [[TYPENODE:![0-9]+]]
+; Debug info must be updated to reflect new address space.
+; CHECK-DAG: [[GVNODE]] = !DIGlobalVariableExpression(var: [[GVVAR:.*]], expr: !DIExpression())
+; CHECK-DAG: [[GVVAR]] = !DIGlobalVariable(name: "static_var", scope: [[CUNODE]],{{.*}} type: [[TYPENODE:![0-9]+]]
 !5 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
 ; CHECK: [[TYPENODE]] = !DIBasicType(name: "char"
 !6 = !{i32 2, !"Dwarf Version", i32 4}
 !7 = !{i32 2, !"Debug Info Version", i32 3}
 !8 = distinct !DISubprogram(name: "foo", linkageName: "func",
       scope: !1, file: !1, line: 3, type: !9, isLocal: false, isDefinition: true, scopeLine: 3,
       flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 ; CHECK: [[FUNCNODE]] = distinct !DISubprogram(name: "foo",
 ; CHECK-SAME: type: [[STYPENODE:![0-9]+]]
 ; CHECK-SAME: unit: [[CUNODE]],
 !9 = !DISubroutineType(types: !10)
 ; CHECK: [[STYPENODE]] = !DISubroutineType
 !10 = !{null}